Invited talk by R.L. Puurunen "Recent Progress in Analysis of the Conformality of Films by Atomic Layer Deposition" at AVS69, Portland, Oregon, Nov 5-10, 2023, https://avs69.avs.org/.
ABSTRACT. Conformality is a fundamental characteristic of atomic layer deposition (ALD) thin film growth technique. “Conformal” film refers to a film that covers all surfaces of a complex three-dimensional substrate with everywhere the same thickness and properties. ALD - invented independently by two groups in 1960s and 1970s - has since late 1990s been transformational in semiconductor technology. Apart from semiconductors, conformal ALD films find applications and interest in widely varied fields such as microelectromechanical systems, pharmaceutical powder processing, optical coatings, battery technologies and heterogeneous catalysts.
Conformality follows directly from the “ideal ALD” principles: growth of material through the use of repeated separate self-terminating (i.e., saturating and irreversible) gas-solid reactions of at least two compatible reactants on a solid surface. Obtaining conformality in practice is not self-evident, however. Reasons for deviation from conformality are multiple, ranging from mass transport limitations to slow reaction kinetics and various deviations from ideal ALD (e.g., by-product reactivity or a continuous chemical vapor deposition (CVD) component through reactant decomposition or insufficient purging). Incomplete conformality can also be intentional: a saturation profile inside a feature can be exposed, to enable an analysis of kinetic parameters of the reactions.
This invited talk will explore recent progress especially by the author and collaborators in understanding ALD conformality and kinetics, obtained via experiments and simulations. Experiments have been made with the recently commercialized (chipmetrics.com) silicon-based PillarHallTM lateral HAR test chips (channel height ~500 nm) and spherical mesoporous high-surface-area materials (average pore diameter ~10 nm, sphere diameter ~1 mm). Simulations are presented for 1d feature-scale models and optionally a recently developed 3d code for spheres. Two codes are available on GitHub: DReaM-ALD (diffusion-reaction model, DRM) and Machball (ballistic transport-reaction model, BTRM). Often it is assumed that diffusion during an ALD process in HAR features is by Knudsen diffusion and free molecular flow conditions prevail (Kn >>1). If so, a characteristic “fingerprint saturation profile” can be obtained, and the slope method (derived for DRM-ALD-Arts, GitHub) can be used to back-extract the lumped sticking coefficient. When diffusion is in the transition flow (Kn ~1) or continuum flow (Kn<<1), the shape of the saturation profile depends on process conditions and the slope method is not applicable.
Slides of invited "ALD 101" tutorial by Puurunen at ALD 2021 Riikka Puurunen
(INVITED) Fundamentals of atomic layer deposition: an introduction (“ALD 101”)
Riikka L. Puurunen, Aalto University School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, AVS 21st International Conference on Atomic Layer Deposition (ALD 2021), Virtual Meeting 27.6.-30.6.2021. Tutorial Session 27.6.2021
ABSTRACT: Atomic layer deposition (ALD) has become of global importance as a processing technology for example in semiconductor device fabrication, and its application areas are continuously expanding. The significance of ALD was highlighted e.g. by the recent (2018) Millennium Technology Prize. Tens of companies are offering ALD tools, and thousands of people are involved in ALD R&D globally. A continuous need exists to educate new people on the fundamentals of ALD.
While ALD for manufacturing may be regarded mature, as a scientific field, ALD—in the author’s view—is developing. For example, understanding of the early history of ALD is evolving, related to the two independent inventions of ALD under the names Atomic Layer Epitaxy in the 1970s and Molecular Layering in the 1960s [1-4]. Also, significantly varying views exist in the field related to the description and meaningfulness of even some core ALD concepts [5].
The purpose of this invited “ALD 101” tutorial is to familiarize a newcomer with fundamentals of ALD. The presentation largely follows the organization of a recent encyclopedia chapter on ALD [6]. Surface chemistry concepts will be introduced, such as ideal ALD from repeated, separate self-terminating (saturating and irreversible) reactions; growth per cycle in ALD; various monolayer concepts relevant to ALD; typical classes of surface reaction mechanisms and saturation-determining factors; growth modes; and ways to describe growth kinetics. Concepts, where differing views exist in the field and which thus need special attention, are pointed out. Typical deviations from the presented ideality are discussed.
For continuous education, a collaborative OpenLearning website on ALD is under construction [7]. Many of the images used in this tutorial—and in Refs. 6 and 7—are available in Wikimedia Commons [8] for easy and free reuse. To contribute to collective learning of the early history of ALD, the open-science effort Virtual Project on the History of ALD [4] still welcomes new volunteer participants.
[1] E. Ahvenniemi et al., J. Vac. Sci. Technol. A 35 (2017) 010801 (2017).[2] R.L. Puurunen, ECS Transactions 86 (6) (2018) 3-17; OA: DOI:10.1149/osf.io/exyv3[3] G.N. Parsons et al., J. Vac. Sci. Technol. A 38 (2020) 037001.[4] http://vph-ald.com[5] J.R. van Ommen, R.L. Puurunen, ALD 2020, https://youtu.be/jqm_wf49WwM[6] J.R. van Ommen, A. Goulas, R.L. Puurunen, Kirk-Othmer Encyclopedia on Chemical Technology, submitted. [7] http://openlearning.aalto.fi, ALD [8] https://commons.wikimedia.org/wiki/Category:Atomic_layer_deposition
Introduction to atomic layer deposition (ALD): principles, applications, futureRiikka Puurunen
<erratum at the bottom / update 3.5.2019> Introductory lecture on Atomic Layer Deposition (ALD) by Prof. Riikka Puurunen, given at Aalto University School of Chemical Engineering on November 8, 2018. Lecture contents: Principles and concepts of ALD; Some history; Applications of ALD; Words on future. In addition to the core lecture contents, discusses where we have ALD layers in our smart mobile phones; mentions (some) faces of ALD in Finland; STG podcasts; Virtual Project on the History of ALD.
Corresponding lecture capture by Panopto available at: https://aalto.cloud.panopto.eu/Panopto/Pages/Viewer.aspx?id=bd0aee67-7ca5-4973-8216-a99200e888b1
Erratum! Small errors spotted in the slides are described below. Updated 3.5.2019.
* slide 44 Luminescent: ZnS:Mg —> not Mg but Mn! --> ZnS:Mn
* slide 54 high-k solution: article not from 2017 but 2007
Adsorption-controlled catalyst preparation by ALDRiikka Puurunen
Lecture slides of Prof. Riikka Puurunen at Aalto University School of Chemical Engineering, CHEM-E1130 Catalysis, 25.2.2019, on the preparation of catalysts by atomic layer deposition.
Graphene is one the wonder materials in modern world,I Shaunak Bhattacharya with help of my group mates has made this presentation. Since I referred to slideshare.net for my presentation it was my duty to give it something back. I would be really happy if my presentation comes handy to anyone.
Battery Show Europe 2022
Presented by D.Sc. Andrew Cook
ALD is an enabling technology for future batteries. ALD technology introduction has been hindered by lack of production scale equipment, but now Beneq R2R ALD technology offers a straightforward scale-up path to mass-production. Beneq has a long experience with R2R ALD on other application areas, and is now applying that know-how to offer R2R ALD solutions for battery manufacturing.
Slides of invited "ALD 101" tutorial by Puurunen at ALD 2021 Riikka Puurunen
(INVITED) Fundamentals of atomic layer deposition: an introduction (“ALD 101”)
Riikka L. Puurunen, Aalto University School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, AVS 21st International Conference on Atomic Layer Deposition (ALD 2021), Virtual Meeting 27.6.-30.6.2021. Tutorial Session 27.6.2021
ABSTRACT: Atomic layer deposition (ALD) has become of global importance as a processing technology for example in semiconductor device fabrication, and its application areas are continuously expanding. The significance of ALD was highlighted e.g. by the recent (2018) Millennium Technology Prize. Tens of companies are offering ALD tools, and thousands of people are involved in ALD R&D globally. A continuous need exists to educate new people on the fundamentals of ALD.
While ALD for manufacturing may be regarded mature, as a scientific field, ALD—in the author’s view—is developing. For example, understanding of the early history of ALD is evolving, related to the two independent inventions of ALD under the names Atomic Layer Epitaxy in the 1970s and Molecular Layering in the 1960s [1-4]. Also, significantly varying views exist in the field related to the description and meaningfulness of even some core ALD concepts [5].
The purpose of this invited “ALD 101” tutorial is to familiarize a newcomer with fundamentals of ALD. The presentation largely follows the organization of a recent encyclopedia chapter on ALD [6]. Surface chemistry concepts will be introduced, such as ideal ALD from repeated, separate self-terminating (saturating and irreversible) reactions; growth per cycle in ALD; various monolayer concepts relevant to ALD; typical classes of surface reaction mechanisms and saturation-determining factors; growth modes; and ways to describe growth kinetics. Concepts, where differing views exist in the field and which thus need special attention, are pointed out. Typical deviations from the presented ideality are discussed.
For continuous education, a collaborative OpenLearning website on ALD is under construction [7]. Many of the images used in this tutorial—and in Refs. 6 and 7—are available in Wikimedia Commons [8] for easy and free reuse. To contribute to collective learning of the early history of ALD, the open-science effort Virtual Project on the History of ALD [4] still welcomes new volunteer participants.
[1] E. Ahvenniemi et al., J. Vac. Sci. Technol. A 35 (2017) 010801 (2017).[2] R.L. Puurunen, ECS Transactions 86 (6) (2018) 3-17; OA: DOI:10.1149/osf.io/exyv3[3] G.N. Parsons et al., J. Vac. Sci. Technol. A 38 (2020) 037001.[4] http://vph-ald.com[5] J.R. van Ommen, R.L. Puurunen, ALD 2020, https://youtu.be/jqm_wf49WwM[6] J.R. van Ommen, A. Goulas, R.L. Puurunen, Kirk-Othmer Encyclopedia on Chemical Technology, submitted. [7] http://openlearning.aalto.fi, ALD [8] https://commons.wikimedia.org/wiki/Category:Atomic_layer_deposition
Introduction to atomic layer deposition (ALD): principles, applications, futureRiikka Puurunen
<erratum at the bottom / update 3.5.2019> Introductory lecture on Atomic Layer Deposition (ALD) by Prof. Riikka Puurunen, given at Aalto University School of Chemical Engineering on November 8, 2018. Lecture contents: Principles and concepts of ALD; Some history; Applications of ALD; Words on future. In addition to the core lecture contents, discusses where we have ALD layers in our smart mobile phones; mentions (some) faces of ALD in Finland; STG podcasts; Virtual Project on the History of ALD.
Corresponding lecture capture by Panopto available at: https://aalto.cloud.panopto.eu/Panopto/Pages/Viewer.aspx?id=bd0aee67-7ca5-4973-8216-a99200e888b1
Erratum! Small errors spotted in the slides are described below. Updated 3.5.2019.
* slide 44 Luminescent: ZnS:Mg —> not Mg but Mn! --> ZnS:Mn
* slide 54 high-k solution: article not from 2017 but 2007
Adsorption-controlled catalyst preparation by ALDRiikka Puurunen
Lecture slides of Prof. Riikka Puurunen at Aalto University School of Chemical Engineering, CHEM-E1130 Catalysis, 25.2.2019, on the preparation of catalysts by atomic layer deposition.
Graphene is one the wonder materials in modern world,I Shaunak Bhattacharya with help of my group mates has made this presentation. Since I referred to slideshare.net for my presentation it was my duty to give it something back. I would be really happy if my presentation comes handy to anyone.
Battery Show Europe 2022
Presented by D.Sc. Andrew Cook
ALD is an enabling technology for future batteries. ALD technology introduction has been hindered by lack of production scale equipment, but now Beneq R2R ALD technology offers a straightforward scale-up path to mass-production. Beneq has a long experience with R2R ALD on other application areas, and is now applying that know-how to offer R2R ALD solutions for battery manufacturing.
The driving engine for the exponential growth of digital information processing systems is scaling down the transistor dimensions. For decades, this has enhanced the device performance and density. However, the International Technology Roadmap for Semiconductors (ITRS) states the end of Moore’s law in the next decade due to the scaling challenges of silicon-based CMOS electronics, e.g. extremely high power density. The forward-looking solutions are the utilization of emerging materials and devices for integrated circuits, e.g. carbon-based materials. The presentation of my Ph.D. work focuses on graphene, one atomic layer of carbon sheet, experimentally discovered in 2004. Since fabrication technology of emerging materials is still in early stages, transistor modeling has been playing an important role for evaluating futuristic graphene-based devices and circuits. The device has been simulated by solving a quantum transport model based on non-equilibrium Green’s function (NEGF) approach, which fully treats short channel-length electrostatic effects and the quantum tunneling effects, leading to the technology exploration of graphene nanoribbon field effect transistors (GNR FETs) for the future. This research presents a comprehensive study of the width-dependence performance of the GNR FETs and the scaling of its channel length down to 2.5 nanometer, investigating its potential use beyond-CMOS emerging technology.
ALD for Industry 2019: Slides of invited tutorial by Prof. Riikka PuurunenRiikka Puurunen
Invited tutorial given by Prof. Riikka Puurunen at the ALD for Industry event, Berlin, 19.3.2019.
Video record taken with Panopto, (to be) shared in Youtube, you find the links e.g. through the blog post: https://blogs.aalto.fi/catprofopen/2019/03/19/prof-puurunen-invited-tutorial-at-ald-for-industry-berlin/
Title: ALD Technology – Introduction, History & Principles
Abstract: This tutorial keynote will introduce atomic layer deposition (ALD) – a variant of chemical vapor deposition - and fundamental principles and concepts related it from a generic viewpoint applicable to any ALD process and reactor. The early history and current usage of ALD are briefly overviewed: who made the first experiments, when, and why? How has the view on the history of ALD evolved? Where is ALD now used, by whom, and why? ALD relies on repeated chemical adsorption steps from gas phase to surface. The status of understanding the adsorption steps of ALD films will be presented and discussed using mainly the archetype trimethylaluminium-water ALD process as example and 3D conformality modelling as additional vehicle. Plenty of links to further sources of information will be included in this keynote presentation.
A related SlideShare: placeholder, where I meant to update the slides afterwards, but this did not succeed as the reupload function has been removed: https://www.slideshare.net/RiikkaPuurunen/ald-for-industry-2019-invited-tutorial-by-prof-riikka-puurunen/RiikkaPuurunen/ald-for-industry-2019-invited-tutorial-by-prof-riikka-puurunen. The update was waiting for the publication of the following review article, which was still in press when giving the presentation: Cremers, Puurunen, Dendooven, Appl. Phys. Rev. (2019), https://doi.org/10.1063/1.5060967. Article published 4.4.2019: Applied Physics Reviews 6, 021302 (2019)
AEROGEL MATERIAL (Aerogel is a material of future. )SONAM PALJOR
An aerogel is solid with air pockets dispersed throughout. Aerogels are essentially the solid framework of a gel.A class of porous, solid materials that exhibit extreme material properties.
Here, include contents are introduction, what is an aerogel?, types, synthesis, properties, advantages , disadvantage and application etc. this presentation paper is very simple and easy to understand about the aerogel material.
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene Presentation
GRAPHENE SYNTHESIS AND ITS APPLICATIONS TERM PAPER PRESENTATIONAman Gupta
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene synthesis process and its current and future applications explained in brief
Feasibility Of Graphene Inks In Printed Electronics V5Vishnu Chundi
Presentation delivered at the International Conference on Nanoscience and Technology,India, January,2012. Evaluating the technical and commercial aspects of using graphene inks for printed electronics applications. Suggested a road-map for the future applications. Touches upon the competing technologies for ITO replacement. Performed SWOT analysis of graphene inks
Atomic Layer Deposition solutions for SiC Power ElectronicsBeneq
Power Electronics International
Brussels, Belgium
19.04.2023
Atomic Layer Deposition solutions for SiC Power Electronics
Integrated ALD passivation/gate dielectric stack for SiC MOSFET
Presented by Mikko Söderlund from Beneq Oy
Graphene, the amazing two-dimensional carbon nanomaterial, has attracted extensive interest in recent years and emerged as the most intensively studied material [1]. In 2004, Geim and Nosovelov at Manchester University successfully isolated single layer graphene by the mechanical cleavage of graphite crystal [2]. This ‘‘thinnest’’ known material exhibits extraordinary electronic, chemical, mechanical, thermal and optical properties which bestowed graphene as a miracle material of the 21st Century. From applicative perspectives, graphene holds a great promise with the potential to be used as energy-storage materials, in nanoelectronics, in catalysis, biomedical, in polymer composites and many more.
RECENT PROGRESS IN THE DEVELOPMENT OF AEROSPACE MATERIALS.pdfharshangak
This presentation covers the design criteria, different types of alloys, composites used in the aerospace industry over the decades , the problems that need to be overcome especially at the high temperature and stress and description of the future aerospace materials are discussed.
This presentation from JEC World 2019 composites trade show and conference highlights different forms of graphene that are used in composites applications with examples of actual products.
Puurunen (on behalf of Järvilehto) oral presentation at ALD 2023 conferenceRiikka Puurunen
ALD 2023, Bellevue, Washington, July 2023
AUDIO: (see 1st page)
Title: Simulated Conformality of ALD Growth Inside Lateral HAR Channels: Comparison Between a Diffusion–Reaction Model and a Ballistic Transport–Reaction Model
Authors: Jänis Järvilehto,1 Jorge A. Velasco,1 Jihong Yim,1 Christine Gonsalves1 and Riikka L. Puurunen1
1Aalto University, School of Chemical Engineering, Department of Chemical and Metallurgical Engineering
Atomic layer deposition (ALD) is known for its ability to produce films of controllable thickness, even in narrow, high-aspect-ratio (HAR) structures [1]. These films can be highly conformal, meaning that the structure is covered by a film of uniform thickness [1,2]. However, when the structure’s aspect ratio is increased sufficiently, deposition becomes limited by the diffusion of the reactants into the deep end of the structure, potentially resulting in the formation of an adsorption front, followed by a region of lower coverage [3]. Theoretical models have been developed to predict film conformality in HAR structures, as reviewed in [2].
This work presents a comparison of a diffusion–reaction model (DRM) developed by Ylilammi et al. [4,5] (Model A) and a ballistic transport–reaction model (BTRM) by Yanguas-Gil and Elam [6,7] (Model B). For the comparison, saturation profiles were generated using both models with similar simulation parameters (Knudsen number Kn >> 1).
Qualitatively, both models produced similar trends in terms of half-coverage penetration depth and slope at half-coverage penetration depth. The saturation profiles were similar in shape, except for the film growth observed at the channel end in Model B. Quantitative examination yielded consistently higher half-coverage penetration depths in Model B. Model A produced steeper slopes at half-coverage penetration depth. In Model B, the discretization resolution was found to affect the penetration depth.
While the models gave qualitatively similar results, quantitatively extracted parameters differed. This finding is consistent with a previous comparison of a DRM and BTRM in the context of low pressure chemical vapor deposition [8]. The quantitative differences are relevant, for example, when the models are fitted to experimental data for the extraction of kinetic parameters, such as the sticking coefficient.
[1] J.R. van Ommen, A. Goulas, and R.L. Puurunen, “Atomic layer deposition,” in Kirk Othmer Encyclopedia of
Chemical Technology, John Wiley & Sons, Inc., 42 p, (2021).
[2] V. Cremers et al., Appl. Phys. Rev. 6 (2019) 021302.
[3] J. Yim and O.M.E. Ylivaara et al., Phys. Chem. Chem. Phys. 22 (2020) 23107-23120.
[4] M. Ylilammi et al., J. Appl. Phys. 123 (2018) 205301.
[5] J. Yim and E. Verkama et al., Phys. Chem. Chem. Phys. 24 (2022) 8645–8660.
[6] A. Yanguas-Gil and J.W. Elam, Theor. Chem. Acc. 133 (2014) 1465.
[7] A. Yanguas-Gil and J.W. Elam, (2013) ...
Catalysis Connected, Utrecht - slides of invited talk by Prof. Riikka PuurunenRiikka Puurunen
Talk given in Utrecht, The Netherlands, August 24, 2019
Title: Atomic layer deposition: Bridging semiconductors to catalysis and beyond
Abstract: This talk will briefly explain the fundamentals of atomic layer deposition (ALD), view key historical turning points of the technique, and attempt to look into the future of ALD in the field of catalysis. ALD, a thin film growth method based on repeated self-terminating gas-solid reactions of compatible compounds, has become known as an enabler of Moore’s law and is today commonplace in the manufacturing of semiconductor devices. Currently, ALD is seen as highly promising for the controlled preparation of heterogeneous catalysts, testified e.g. from the number of reviews that appear on the topic. ALD can be used to grow films or nanoparticles and even single sites, and it can be similarly applied on powders, engineered 3D structures, and flat model catalysts.
The driving engine for the exponential growth of digital information processing systems is scaling down the transistor dimensions. For decades, this has enhanced the device performance and density. However, the International Technology Roadmap for Semiconductors (ITRS) states the end of Moore’s law in the next decade due to the scaling challenges of silicon-based CMOS electronics, e.g. extremely high power density. The forward-looking solutions are the utilization of emerging materials and devices for integrated circuits, e.g. carbon-based materials. The presentation of my Ph.D. work focuses on graphene, one atomic layer of carbon sheet, experimentally discovered in 2004. Since fabrication technology of emerging materials is still in early stages, transistor modeling has been playing an important role for evaluating futuristic graphene-based devices and circuits. The device has been simulated by solving a quantum transport model based on non-equilibrium Green’s function (NEGF) approach, which fully treats short channel-length electrostatic effects and the quantum tunneling effects, leading to the technology exploration of graphene nanoribbon field effect transistors (GNR FETs) for the future. This research presents a comprehensive study of the width-dependence performance of the GNR FETs and the scaling of its channel length down to 2.5 nanometer, investigating its potential use beyond-CMOS emerging technology.
ALD for Industry 2019: Slides of invited tutorial by Prof. Riikka PuurunenRiikka Puurunen
Invited tutorial given by Prof. Riikka Puurunen at the ALD for Industry event, Berlin, 19.3.2019.
Video record taken with Panopto, (to be) shared in Youtube, you find the links e.g. through the blog post: https://blogs.aalto.fi/catprofopen/2019/03/19/prof-puurunen-invited-tutorial-at-ald-for-industry-berlin/
Title: ALD Technology – Introduction, History & Principles
Abstract: This tutorial keynote will introduce atomic layer deposition (ALD) – a variant of chemical vapor deposition - and fundamental principles and concepts related it from a generic viewpoint applicable to any ALD process and reactor. The early history and current usage of ALD are briefly overviewed: who made the first experiments, when, and why? How has the view on the history of ALD evolved? Where is ALD now used, by whom, and why? ALD relies on repeated chemical adsorption steps from gas phase to surface. The status of understanding the adsorption steps of ALD films will be presented and discussed using mainly the archetype trimethylaluminium-water ALD process as example and 3D conformality modelling as additional vehicle. Plenty of links to further sources of information will be included in this keynote presentation.
A related SlideShare: placeholder, where I meant to update the slides afterwards, but this did not succeed as the reupload function has been removed: https://www.slideshare.net/RiikkaPuurunen/ald-for-industry-2019-invited-tutorial-by-prof-riikka-puurunen/RiikkaPuurunen/ald-for-industry-2019-invited-tutorial-by-prof-riikka-puurunen. The update was waiting for the publication of the following review article, which was still in press when giving the presentation: Cremers, Puurunen, Dendooven, Appl. Phys. Rev. (2019), https://doi.org/10.1063/1.5060967. Article published 4.4.2019: Applied Physics Reviews 6, 021302 (2019)
AEROGEL MATERIAL (Aerogel is a material of future. )SONAM PALJOR
An aerogel is solid with air pockets dispersed throughout. Aerogels are essentially the solid framework of a gel.A class of porous, solid materials that exhibit extreme material properties.
Here, include contents are introduction, what is an aerogel?, types, synthesis, properties, advantages , disadvantage and application etc. this presentation paper is very simple and easy to understand about the aerogel material.
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene Presentation
GRAPHENE SYNTHESIS AND ITS APPLICATIONS TERM PAPER PRESENTATIONAman Gupta
For free download Subscribe to https://www.youtube.com/channel/UCTfiZ8qwZ_8_vTjxeCB037w and Follow https://www.instagram.com/fitrit_2405/ then please contact +91-9045839849 over WhatsApp.
Graphene synthesis process and its current and future applications explained in brief
Feasibility Of Graphene Inks In Printed Electronics V5Vishnu Chundi
Presentation delivered at the International Conference on Nanoscience and Technology,India, January,2012. Evaluating the technical and commercial aspects of using graphene inks for printed electronics applications. Suggested a road-map for the future applications. Touches upon the competing technologies for ITO replacement. Performed SWOT analysis of graphene inks
Atomic Layer Deposition solutions for SiC Power ElectronicsBeneq
Power Electronics International
Brussels, Belgium
19.04.2023
Atomic Layer Deposition solutions for SiC Power Electronics
Integrated ALD passivation/gate dielectric stack for SiC MOSFET
Presented by Mikko Söderlund from Beneq Oy
Graphene, the amazing two-dimensional carbon nanomaterial, has attracted extensive interest in recent years and emerged as the most intensively studied material [1]. In 2004, Geim and Nosovelov at Manchester University successfully isolated single layer graphene by the mechanical cleavage of graphite crystal [2]. This ‘‘thinnest’’ known material exhibits extraordinary electronic, chemical, mechanical, thermal and optical properties which bestowed graphene as a miracle material of the 21st Century. From applicative perspectives, graphene holds a great promise with the potential to be used as energy-storage materials, in nanoelectronics, in catalysis, biomedical, in polymer composites and many more.
RECENT PROGRESS IN THE DEVELOPMENT OF AEROSPACE MATERIALS.pdfharshangak
This presentation covers the design criteria, different types of alloys, composites used in the aerospace industry over the decades , the problems that need to be overcome especially at the high temperature and stress and description of the future aerospace materials are discussed.
This presentation from JEC World 2019 composites trade show and conference highlights different forms of graphene that are used in composites applications with examples of actual products.
Puurunen (on behalf of Järvilehto) oral presentation at ALD 2023 conferenceRiikka Puurunen
ALD 2023, Bellevue, Washington, July 2023
AUDIO: (see 1st page)
Title: Simulated Conformality of ALD Growth Inside Lateral HAR Channels: Comparison Between a Diffusion–Reaction Model and a Ballistic Transport–Reaction Model
Authors: Jänis Järvilehto,1 Jorge A. Velasco,1 Jihong Yim,1 Christine Gonsalves1 and Riikka L. Puurunen1
1Aalto University, School of Chemical Engineering, Department of Chemical and Metallurgical Engineering
Atomic layer deposition (ALD) is known for its ability to produce films of controllable thickness, even in narrow, high-aspect-ratio (HAR) structures [1]. These films can be highly conformal, meaning that the structure is covered by a film of uniform thickness [1,2]. However, when the structure’s aspect ratio is increased sufficiently, deposition becomes limited by the diffusion of the reactants into the deep end of the structure, potentially resulting in the formation of an adsorption front, followed by a region of lower coverage [3]. Theoretical models have been developed to predict film conformality in HAR structures, as reviewed in [2].
This work presents a comparison of a diffusion–reaction model (DRM) developed by Ylilammi et al. [4,5] (Model A) and a ballistic transport–reaction model (BTRM) by Yanguas-Gil and Elam [6,7] (Model B). For the comparison, saturation profiles were generated using both models with similar simulation parameters (Knudsen number Kn >> 1).
Qualitatively, both models produced similar trends in terms of half-coverage penetration depth and slope at half-coverage penetration depth. The saturation profiles were similar in shape, except for the film growth observed at the channel end in Model B. Quantitative examination yielded consistently higher half-coverage penetration depths in Model B. Model A produced steeper slopes at half-coverage penetration depth. In Model B, the discretization resolution was found to affect the penetration depth.
While the models gave qualitatively similar results, quantitatively extracted parameters differed. This finding is consistent with a previous comparison of a DRM and BTRM in the context of low pressure chemical vapor deposition [8]. The quantitative differences are relevant, for example, when the models are fitted to experimental data for the extraction of kinetic parameters, such as the sticking coefficient.
[1] J.R. van Ommen, A. Goulas, and R.L. Puurunen, “Atomic layer deposition,” in Kirk Othmer Encyclopedia of
Chemical Technology, John Wiley & Sons, Inc., 42 p, (2021).
[2] V. Cremers et al., Appl. Phys. Rev. 6 (2019) 021302.
[3] J. Yim and O.M.E. Ylivaara et al., Phys. Chem. Chem. Phys. 22 (2020) 23107-23120.
[4] M. Ylilammi et al., J. Appl. Phys. 123 (2018) 205301.
[5] J. Yim and E. Verkama et al., Phys. Chem. Chem. Phys. 24 (2022) 8645–8660.
[6] A. Yanguas-Gil and J.W. Elam, Theor. Chem. Acc. 133 (2014) 1465.
[7] A. Yanguas-Gil and J.W. Elam, (2013) ...
Catalysis Connected, Utrecht - slides of invited talk by Prof. Riikka PuurunenRiikka Puurunen
Talk given in Utrecht, The Netherlands, August 24, 2019
Title: Atomic layer deposition: Bridging semiconductors to catalysis and beyond
Abstract: This talk will briefly explain the fundamentals of atomic layer deposition (ALD), view key historical turning points of the technique, and attempt to look into the future of ALD in the field of catalysis. ALD, a thin film growth method based on repeated self-terminating gas-solid reactions of compatible compounds, has become known as an enabler of Moore’s law and is today commonplace in the manufacturing of semiconductor devices. Currently, ALD is seen as highly promising for the controlled preparation of heterogeneous catalysts, testified e.g. from the number of reviews that appear on the topic. ALD can be used to grow films or nanoparticles and even single sites, and it can be similarly applied on powders, engineered 3D structures, and flat model catalysts.
Isabelle Diacaire - From Ariadnas to Industry R&D in optics and photonicsAdvanced-Concepts-Team
Presentation in the Science Coffee of the Advanced Concepts Team of the European Space Agency.
Date: 28.02.2024
Speaker: Isabelle Dicaire (CCTT Optech)
Topic: From Ariadnas to Industry R&D in optics and photonics
47 Results from polarized experiments at LEGS and GRAAL - AIP Conference Proc...Cristian Randieri PhD
Results from polarized experiments at LEGS and GRAAL - The 8th International Workshop on the Physics of Excited Nucleons, NSTAR 2011, Newport News, VA, (USA) 17-20 May 2011. AIP Conference Proceedings, April 2012, Vol. 1432, pp. 56-61, ISSN: 0094-243X, doi: 10.1063/1.3701189
di A. D'Angelo, K. Ardashev, C. Bade, O. Bartalini, V. Bellini, M. Blecher, J. P. Bocquet, M. Capogni, A. Caracappa, L. E. Casano, M. Castoldi, R. Di Salvo, A. Fantini, D. Franco, G. Gervino, F. Ghio, G. Giardina, C. Gibson, B. Girolami, A. Giusa, H. Glükler, K. Hicks, S. Hoblit, A. Honig, T. Kageya, M. Khandaker, O. C. Kistner, S. Kizilgul, S. Kucuker, A. Lapik, A. Lehmann, P. Levi Sandri, A. Lleres, M. Lowry, M. Lucas, J. Mahon, F. Mammoliti, G. Mandaglio, M. Manganaro, L. Miceli, D. Moricciani, A. Mushkarenkov, V. Nedorezov, B. Norum, M. Pap, B. Preedom, H. Seyfarth, C. Randieri, D. Rebreyend, N. Rudnev, G. Russo, A. Sandorfi, C. Schaerf, M. L. Sperduto, H. Ströher, M. C. Sutera, C. E. Thorn, A. Turinge, V. Vegna, C. S. Whisnant, K. Wang, X. Wei (2012)
Abstract
Compton backscattering gamma ray beams are characterized by a high degree of linear and circular polarization with low unpolarized backgrounds and have proven to provide very precise measurements of polarization observables. Latest results from LEGS and GRAAL experiments on proton and deuteron targets are presented. The Σ beam asymmetry for ω photoproduction has been measured by the GRAAL collaboration for both the ω→π0γ and the ω→π+π-π0 decay channels on the proton target; single and double polarization asymmetries have been provided also for the K photoproduction channel. E and G double polarization asymmetries for single pion photoproduction on the proton and deuteron have been measured at LEGS using a frozen spin HD target.
Computations of Acoustic Wave Propagation in II-VI Hexagonal Semiconductor Compounds
Original Research Article
Journal of Chemistry and Materials Research Vol. 1 (3), 2014, 65–70
Pramod Kumar Yadawa *
Hole transport materials (HTMs) have a significant impact on the effectiveness of organic electronic devices; therefore, we present a molecular architecture of pyrazino[2,3-g]quinoxaline (PQ10)-based room-temperature organic liquid crystalline semiconductor (OLCS) as an alternative HTM. The PQ10 compound exhibits three different rectangular columnar (Colr) phases offering an impressive hole mobility of 8.8 × 10−3 cm2V−1s−1 which is found to be dexterous than most of existing polymeric hole transport materials. The charge transport mechanism is governed by the hole polarons hopping through H-aggregates of the PQ10 molecules and the hole mobility remains nearly constant throughout the mesophase range, but it decreases with increasing applied electric field. The current-voltage characteristics of the PQ10 have also been investigated in all three Colr phases and explained via the Poole-Frenkel conduction mechanism. The dielectric spectroscopy has been eventually carried out to understand the nature of dielectric permittivity and conductivity as a function of temperature and a correlation is established between the molecular architecture of the Colr phases and aforementioned physical properties. Solar cell simulation has been additionally performed to demonstrate that the PQ10 material can be a better choice as HTM for organic electronics and photovoltaic applications.
Puurunen invited talk at IUPAC|Chains2023, The Hague, Netherlands, Aug 20-25,...Riikka Puurunen
Title: Atomic layer deposition: Introduction and progress examples
RECORDED AUDIO: https://aalto.cloud.panopto.eu/Panopto/Pages/Viewer.aspx?id=835b50be-f687-463a-b0dc-b06900e0b47b
IUPAC|CHAINS2023 August 20-25, 2023. ‘Connecting Chemical Worlds’
Invited talk in parallel session 62: Advanced Thin Film Technology of Energy and Smart Materials
ABSTRACT
Atomic layer deposition (ALD), a thin film growth method based on self-terminating gas-solid reactions, has enabled the miniaturization of semiconductor devices in 2000s and finds commercial and emerging applications in varied other fields [1]. ALD has been invented independently twice [2,3]; in 1998, the Finnish inventor of ALD Tuomo Suntola received the Millennium Technology Prize for his pioneering work. This invited talk will first introduce the chemical principles of ALD. The ideally self-terminating (saturating, irreversible) reactions lead to almost unparalleled uniformity and conformality of the films, and to expanding interest in the ALD technique. Second, case examples will be shared of recent research in Puurunen’s group at Aalto University related to preparation of heterogeneous catalysts by ALD and conformality investigations by experiments and modelling. As the speaker is interested in bringing more openness to science and education in a sustainable way, recent progress in Open Science in the field of ALD will be also briefly touched upon.
References:
[1] J.R. van Ommen, A. Goulas, R.L. Puurunen, “Atomic layer deposition”, in Kirk-Othmer Encyclopedia of Chemical Technology, 2021, https://doi.org/10.1002/0471238961.koe00059.
[2] R.L. Puurunen, “A Short History of Atomic Layer Deposition: Tuomo Suntola's Atomic Layer Epitaxy”, Chem. Vap. Deposition 20 (2014) 332-344. https://doi.org/10.1002/cvde.201402012
[3] A.A. Malygin, V.E. Drozd, A.A. Malkov, V.M. Smirnov, “From V. B. Aleskovskii's “Framework” Hypothesis to the Method of Molecular Layering/Atomic Layer Deposition”, Chem. Vap. Deposition 21 (2015) 216-240. https://doi.org/10.1002/cvde.201502013
Surface coverage in atomic layer deposition - slides related to invited talk ...Riikka Puurunen
Invited talk given at the Workshop on Fundamentals of Atomic Layer Deposition (ALD): Modelling and ValidationTU Delft, The Netherlands, July 3, 2019. Talk was recorded by TU Delft staff and is to be shared later. Website: https://www.tudelft.nl/en/faculty-of-applied-sciences/about-faculty/departments/chemical-engineering/scientific-staff/van-ommen-group/workshop-fundamentals-of-ald/. Twitter hashtag: #ALDfun
Under a Compulsory Course of "Materials Physics and Technology for Nanoelectronics" a team of BE Students of Nanotechnology, Nanoelectronics and Bionnotechnology prepared this seminar for Prof. Marc Heyns, marc.heyns@imec.be Kapeldreef 75, B-3001 Heverlee IMEC Building IV, room 2.33
Tel: 016 281 348
● Control of the Dust Vertical Distribution Over Western Africa by Conversion and SCavenginging
● SOME FEATURS of Black Carbon Aerosols Connect with Regional Climate Over Pristine Environment
● Evaluation of the Mechanisms Acting on the Atlantic Meridional Overturning Circulation in Cesm2 for the 1pCTCO2 Experiment
● Analysis of Extreme Temperature Variability in RWANDA
● Seasonal Variability of Rainfall and Thunders Pattern in Kenya
● Multi-DECADAL Changes of the IMPACT of El Niño Events on Tibetan Plateau Summer Precipity
● Assessment of the Intertropical Convergence Zone Over The Atlantic Ocean Throughmmm Based on Precipity
Invited talk at 98th CSC: Surface chemistry of ALD: mechanisms and conformality Riikka Puurunen
Abstract of the presentation:
Atomic layer deposition (ALD) is a thin film growth method generally applicable for the growth of conformal, highquality
inorganic material layers down to the nanometer thickness range. ALD is indifferent to the morphology of the
underlying substrate and covers even most complex 3-D shapes with a uniform film; as a consequence, ALD is used
in an ever-increasing field of applications from catalysts to photovoltaics to microelectronics and beyond. ALD
belongs to the general class of chemical vapour deposition (CVD) techniques. The speciality of ALD is the use of
repeated self-terminating (saturating, irreversible) gassolid reactions of at least two reactants for the film growth; ALD
is therefore non-continuous in nature, as opposed to the continuous CVD processes. In this presentation, I will
discuss some challenges related to understanding the surface chemistry of ALD. The commonly-used
trimethylaluminium-water ALD process to deposit Al2O3 is used as case example, as it is often presented as model
case for ALD. I will also discuss the characteristics of ALD film conformality, as detected by using microscopic lateral
high-aspect-ratio structures ("VTT μLHAR") [J. Vac. Sci. Technol. A 33, 010601 (2015)]. Here, the gap height is in
the range of 100 nm's and the aspect ratio (AR) can be extremely challenging, e.g. up to 25 000:1. Finally, I will
briefly introduce the on-going international volunteer-based Virtual Project on the History of ALD (http://vph-ald.com),
where new participants are still welcome.
Acknowledgement: The author thanks Finnish Centre of Excellence in Atomic Layer Deposition for funding.
"On the fundamentals of ALD: the importance of getting the picture right" by ...Riikka Puurunen
Presentation at the AVS 20th International Conference on Atomic Layer Deposition (ALD 2020) featuring the 7th International Atomic Layer Etching Workshop (ALE 2020), online, 29.6.-1.7.2020.
Authors: Riikka L. Puurunen and J. Ruud van Ommen
Abstract text:
Atomic layer deposition (ALD) has become of global importance as a fundamental building block for example in semiconductor device fabrication, and also gained more visibility (e.g., the Millennium Technology Prize 2018). In recent years, the number of ALD processes has increased, new groups have entered the field, and fundamental insights have been gained. At the same time, significantly varying views exist in the field related to the description and meaningfulness of some core ALD concepts. Open, respectful but critical scientific discussion would be needed around these concepts - for example at this AVS ALD/ALE conference, the world’s largest conference on ALD.
The discussion on terminology of ALD that started in the 2005 surface chemistry review [1] is continued in this contribution, taking into account recent progress reported in leading reviews such as Ref. 2. We start by considering the concept of “ideal ALD”. How should it be defined so that the well-recognized practical benefits of ALD are maintained, while no unnecessary utopian requirements are created? We propose that the repetition of well-separated saturating, irreversible chemisorption reactions (which by definition saturate at a monolayer of the chemisorbed species) is sufficient to reproduce the benefits of ALD. A requirement of “full monolayer growth” (of the ALD-grown material), progressed e.g. in numerous cartoons of ALD, is not needed. There should also be no reason to expect a constant growth per cycle (GPC) within the ALD window (the saturating chemistry is typically weakly temperature dependent), although such a scheme is repeatedly reproduced in the literature.
Other fundamental concepts will be pointed out, where mix-ups have been created. For example, although the GPC (or etch per cycle in Atomic Layer Etching) is a saturation-related concept and not a time-related kinetic parameter, Arrhenius plots have been sometimes created to extract “activation energies” of some process from these “growth/etch rates (per cycle)”. Also, “Langmuir adsorption” has been adopted as a way to model ALD in a simplified, lumped way. Notably, Langmuir adsorption assumes no interaction between adsorbed species, contrasting some recent discussions of “cooperative effects” in ALD. Also, concepts of “adsorption isotherm” and amount adsorbed vs. time (“saturation curve”), although fundamentally different, have been mixed.
We hope that the discussion on the fundamentals of ALD will be intensified, and that the discussion will help the field progress and flourish in the future.
[1] Puurunen, J. Appl. Phys. 97 (2005) 121301.
[2] Richey, de Paula, Bent, J. Chem. Phys. 152 (2020) 040902.
ALD for Industry 2019: Invited tutorial by Prof. Riikka Puurunen Riikka Puurunen
Oops! Could not update this placeholder with the final presentation as planned: The reupload function that I planned to use, has been removed from SlideShare, see: https://www.slideshare.net/dolaneconslide/bring-back-reupload
Slides uploaded separately: https://www.slideshare.net/RiikkaPuurunen/ald-for-industry-2019-slides-of-invited-tutorial-by-prof-riikka-puurunen
Originally, this update was waiting for the publication of a review article to be published on ALD conformality: Cremers, Puurunen, Dendooven, Appl. Phys. Rev. (2019), https://doi.org/10.1063/1.5060967. Article published 4.4.2019: Applied Physics Reviews 6, 021302 (2019)
Related post in Catalysis Professor's Open: https://blogs.aalto.fi/catprofopen/2019/03/19/prof-puurunen-invited-tutorial-at-ald-for-industry-berlin/
On the history and future of ALD: VPHA, conformality analysis, mechanismsRiikka Puurunen
Invited presentation at the HERALD COST MP1402 event in Riga (Riika), Latvia, May 22-23, 2017.
Topics:
1) History of atomic layer deposition (ALD)
2) Conformality analysis of ALD and other thin films
3) Surface chemistry questions in ALD
Presentation dedicated to the memory of Mr. Sven Lindfors, pioneer in building ALD reactors, close collaborator of Dr. Tuomo Suntola from 1975.
Slides of my first invited talk at a conference, the ALD 2005 conference in San Jose 2005, about ALD modelling. ALD is fantastic, but fantastic is not perfect :)
---
R. L. Puurunen, Atomic-scale modelling of atomic layer deposition processes, American Vacuum Society Topical Conference on Atomic Layer Deposition (ALD 2005), San Jose, California, August 8-10, 2005. Invited talk.
Slides of invited talk on ALD for MEMS at the AVS-ALD conference ALD 2009 Monterey, California, USA
---
Full reference:
R. L. Puurunen, M. Blomberg, H. Kattelus, ALD layer in MEMS fabrication, 9th International Conference on Atomic Layer Deposition “ALD 2009”, Monterey, California, July 19-22, 2009. Invited talk.
Slides of an invited talk, given at EuroCVD in 2007
R. L. Puurunen, Understanding the surface chemistry of atomic layer deposition: achievements and challenges, Sixteenth European Conference on Chemical Vapor Deposition, EuroCVD-16. Den Haag, The Netherlands, 16 - 21 Sept. 2007. Book of Extended Abstracts. Klein, C.R. (Ed.). Delft University of Technology (2007), 11. Invited talk.
History of ald riikka puurunen 15.11.2013 finalRiikka Puurunen
Invited seminar talk by R. L. Puurunen, November 15, 2013, Beneq and ETU (LETI) joint ALD laboratory opening seminar, St. Petersburg, Russia, title: History of ALD: from lab research to industrial applications
ALD ATO nanolaminates with adjustable electrical properties, poster published...Riikka Puurunen
R. L. Puurunen, H. Kattelus, ALD ATO nanolaminates with adjustable electrical properties, 9th International Conference on Atomic Layer Deposition “ALD 2009”, Monterey, California, July 19-22, 2009. Poster presentation.
Acknowledgement (from the Abstract):
Acknowledgements: The authors are grateful to Ari Häärä for making the electrical measurements and to Sari Sirviö for supervising part of the sample fabrication and for initial interpretations of the results of the electrical measurements. This work was performed within the “ALDKOMP” project funded by Tekes (Finnish Funding Agency for Technology and Innovation).
Poster presented at the AVS ALD 2005 conference. This contains Al2O3 solubility data in deionized water and a report on the "bubbles" which form on ALD Al2O3 when heated. This work has been cited sometimes especially for the bubble formation, and now I want to make it easily accessible for all.
---
Controlling the Solubility of ALD Aluminium Oxide in Deionised Water
Riikka L. Puurunen, Jyrki Kiihamäki and Hannu Kattelus
VTT Technical Research Centre of Finland
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Nutraceutical market, scope and growth: Herbal drug technology
Puurunen invited AVS69 ALD-conformality.pptx
1. Puurunen and coworkers, ALD 2023, Jul 23-26, 2023, Bellevue, Washington
Riikka L. Puurunen
Aalto University, School of Chemical Engineering,
Department of Chemical and Metallurgical Engineering
Recent Progress in
Analysis of the
Conformality of Films
by Atomic Layer
Deposition
AVS 69, Nov 5-10, 2023
Portland, Oregon, USA
From
pillarhall.com,
accessed
5.11.2023.
Photo credit:
Riikka Puurunen
& Mari
Laamanen;
edited by VTT
rA
rI
Open Science
2. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Why conformality studies?
Semiconductor devices need (new) thin films
of ever better conformality
● Initial process development
● Compare processes & choose best
● Compare tools & vendors
● Understand processes (kinetics!)
→ model & simulate processes &
tools
● …
Ovanesyan et al., J. Vac. Sci. Technol. A 37 (2019)
060904; DOI:10.1116/1.5113631 (CC BY)
1.
3. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Brief historical perspective: ALD conformality studies
Suntola, MRS fall
meeting 1994, Boston, MA,
USA. Figure in:
DOI:10.1002/cvde.201402012
Ritala et al., Chem. Vap.
Deposition 5 (1999) 7-9;
DOI:10.1002/(SICI)1521-
3862(199901)5:1<7::AID-
CVDE7>3.0.CO;2-J
Gordon et al., Chem. Vap.
Deposition 9 (2003) 73-78;
DOI:10.1002/cvde.200390005
Dendooven et al.,
J. Electrochem. Soc. 156
(2009) P64-P67;
DOI:10.1149/1.3072694
Also: porous high-surface-area materials
AR
~5:1
AR
43:1
Gao et al., J. Vac. Sci.
Technol. A. 33 (2015)
010601;
DOI:10.1116/1.4903941
AR
100:1
AR
25,000:1
step
Haukka, Lakomaa, Suntola, Stud. Surf.
Chem. Catal. 120 Part A (1999) 715–750;
DOI:10.1016/S0167-2991(99)80570-9
Gayle et al., Chem. Mater. 33 (2021) 5572–5583;
DOI:10.1021/acs.chemmater.1c00770
AR
>60,000:1
1.
4. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Brief historical perspective: ALD conformality studies
Suntola, MRS fall
meeting 1994, Boston, MA,
USA. Figure in:
DOI:10.1002/cvde.201402012
Ritala et al., Chem. Vap.
Deposition 5 (1999) 7-9;
DOI:10.1002/(SICI)1521-
3862(199901)5:1<7::AID-
CVDE7>3.0.CO;2-J
Gordon et al., Chem. Vap.
Deposition 9 (2003) 73-78;
DOI:10.1002/cvde.200390005
Dendooven et al.,
J. Electrochem. Soc. 156
(2009) P64-P67;
DOI:10.1149/1.3072694
Also: porous high-surface-area materials
Gao et al., J. Vac. Sci.
Technol. A. 33 (2015)
010601;
DOI:10.1116/1.4903941
step
Haukka, Lakomaa, Suntola, Stud. Surf.
Chem. Catal. 120 Part A (1999) 715–750;
DOI:10.1016/S0167-2991(99)80570-9
Gayle et al., Chem. Mater. 33 (2021) 5572–5583;
DOI:10.1021/acs.chemmater.1c00770
1.
Review, new term
proposed: Hole-
equivalent aspect
ratio (EAR)
Cremers, Puurunen,
Dendooven, Appl. Phys.
Rev. 6 (2019) 021302;
DOI:10.1063/1.5060967
AR
~5:1
EAR
~2.5:1
AR
43:1
EAR
43:1
AR
100:1
EAR
50:1
AR
25,000:1
EAR
12,500:1
AR
>60,000:1
EAR
>60,000:1
5. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Brief historical perspective: kinetic/conformality modelling
1.
There are many more papers, see review:
Cremers, Puurunen, Dendooven, Appl. Phys. Rev. 6 (2019)
021302; DOI:10.1063/1.5060967
Macball
April 2020
6. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
New terminology for ALD saturation (/thickness) profiles
Yim, Ylivaara et al., Phys. Chem. Chem. Phys. 22
(2020) 23107-23120; DOI:10.1039/D0CP03358H
1.
Dimensionless distance x̃ = x/H
(a) as-measured:
Ylilammi et al., 2018
(b) scaled:
Yim et al., 2020
(c) Type 1 normalized:
e.g. Arts et al., 2019
(d) Type 2 normalized:
Many earlier publications
Speaker’s
favourite
7. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Contents
1. Introduction to conformality studies (done already)
2. Some modelling fundamentals
○ Atomic layer deposition, mean free path & Knudsen
number (diffusion regimes), Langmuir adsorption,
modelling of reactant transport
3. PillarHallTM LHAR conformality analysis concept
4. Recent progress - experiments, results
5. Outlook
+ Plenty of extra materials
8. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Atomic
layer
deposition
(ALD)
Van Ommen,
Goulas, Puurunen,
“Atomic layer
deposition” in
Kirk-Othmer
Encyclopedia of
Chemical
Technology, 2021,
https://doi.org/10.10
02/0471238961.koe
00059
Images in
Wikimedia
Commons
Repeated
self-
terminating
gas-solid
reactions
2.
9. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Knudsen number reveals the diffusion regime
Mean free path (λ)
From kinetic theory of gases
2.
Collision cross section
σi,j = π ( ri + rj )2 *
Knudsen number
Kn = λ / h
* Mistake in this formula (Eq. 4) of DOI:10.1063/1.5060967 , correction in
footnote (**) of Yim, Verkama et al., Phys. Chem. Chem. Phys. 24 (2022)
8645-8660; DOI:10.1039/D1CP04758B .
Kn >>1
Free molecular flow
(Knudsen diffusion)
Kn ~1
Transition regime
Kn <<1
Continuum
(molecular diffusion)
rA
rI
By A. Greg (Greg L at English Wikipedia) -
Own work, Public Domain,
https://commons.wikimedia.org/w/index.php?c
urid=1325234
A = Reactant A
I = Inert
10. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Langmuir
adsorption
2.
Van Ommen, Goulas, Puurunen,“Atomic layer deposition” in Kirk-Othmer Encyclopedia of Chemical
Technology, 2021, https://doi.org/10.1002/0471238961.koe00059. Images courtesy of Arts and co-workers.
A + * ⇌ A*
Reaction rate equation
Järvilehto et al. Phys. Chem.
Chem. Phys. 25 (2023) 22952-
22964;
DOI:10.1039/D3CP01829F
Diffusion-limited hT > 1 Reaction-limited hT << 1
Thiele modulus hT =
adsorption rate
diffusion rate
11. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Reactant transport in HAR features
Fick’s law of diffusion Ballistic transport
Monte Carlo
2.
Poodt et al., J. Vac. Sci. Technol. A 35 (2017)
021502; DOI:10.1116/1.4973350
Järvilehto et al. Phys. Chem. Chem. Phys. 25 (2023) 22952-22964; DOI:10.1039/D3CP01829F
Original papers:
Ylilammi et al., J. Appl. Phys. 123 (2018) 205301; DOI:10.1063/1.5028178
Yanguas-Gil and J. W. Elam, Theor. Chem. Acc. 133 (2014) 1465; DOI:10.1007/s00214-014-1465-x
Kn >>1
Kn: any
Kn: any
12. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
~Ten years of PillarHallTM LHAR
www.pillarhall.com
1st gen prototype [ 2nd gen ] 3rd gen, LHAR3 4th gen, LHAR4
Tekes (Business Finland) proj. PillarHall
Academy of Finland (now Research Council of Finland) proj. ALDCoE
Trademark ~2015
PillarHallTM
Customers, investors etc. → →
www.chipmetrics.com
Dr. Mikko Utriainen
Puurunen
Professor
2017 →
Aalto
Univ.
2 scientific articles
1st: Gao et al. 2015
DOI:10.1116/1.4903941
[ 0 articles ]
>20 scientific articles for LHAR3+LHAR4
“LHAR3 core paper”: Yim, Ylivaara et al., 2020
DOI:10.1039/D0CP03358H
ALD Stories
Podcast Ep. 14
3.
13. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
PillarHallTM LHAR conformality analysis concept
1 Optical analysis
through membrane
2 Membrane removed,
surface exposed for analysis
Kia et al.,
Nanomaterials,
2019,
DOI:10.3390/nan
o9071035
Reflectometer line scans
Yim, Ylivaara et al.,
PCCP, 2020,
DOI:10.1039/D0CP03358H
3.
14. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
PillarHallTM LHAR: measurement vs. simulation
Yim, Ylivaara, Ylilammi, Korpelainen, Haimi, Verkama, Utriainen, Puurunen, Saturation profile based conformality analysis
for atomic layer deposition: aluminum oxide in lateral high-aspect-ratio channels,
Phys. Chem. Chem. Phys. 22 (2020) 23107-23120; DOI:10.1039/D0CP03358H
Measurement Simulation (Ylilammi model)
TMA + water
300°C
3.
as-measured Type 1 norm.
scaled as-measured Type 1 norm.
scaled
16. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Effect of varied parameters on thickness profile (1/2)
E.g.: Penetration depth ~∝ (GPC)-1
Yim, Ylivaara et al.,
TMA-water,
Phys. Chem. Chem.
Phys., 22 (2020)
23107-23120;
DOI:10.1039/D0CP0
3358H
● Observed experimentally
○ Mattinen et al., Ir processes
Langmuir 32 (2016) 10559–10569;
DOI:10.1021/acs.langmuir.6b03007
Yim, Verkama, Velasco, Arts, Puurunen, Phys. Chem. Chem. Phys. 24
(2022) 8645-8660; DOI https://doi.org/10.1039/D1CP04758B
4.
17. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Effect of varied parameters on thickness profile (2/2)
Comparison of diffusion regimes
Kn >> 1
Free molecular flow
Kn ~ 1
Transition regime
Yim, Verkama et al.,
Phys. Chem. Chem. Phys. 24
(2022) 8645-8660; DOI
https://doi.org/1
0.1039/D1CP04758B
DReaM-ALD
4.
18. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Saturation profile contains
kinetic information
Ylilammi, Ylivaara, Puurunen, J. Appl. Phys. 123 (2018) 205301; DOI:10.1063/1.5028178
4.
19. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Arts et al. slope method* to back-extract sticking coefficient
Arts, Vandalon, Puurunen, Utriainen, Gao, Kessels,
Knoops, J. Vac. Sci. Technol. A (2019) 37;
DOI: 10.1116/1.5093620
*Name “slope method” in use since Yim et al., Phys. Chem. Chem. Phys., 24 (2022) 8645-8660: DOI:10.1039/D1CP04758B
● Slope method based on Yanguas-Gil & Elam DR
model, implemented by Arts (drm-ald-arts)
● Requires Kn >>1
● Other works show similar trends
4.
Yim, Verkama, Velasco, Arts,
Puurunen, Phys. Chem.
Chem. Phys. 24 (2022) 8645-
8660;
DOI:10.1039/D1CP04758B
20. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
For PEALD, penetration depth → info on plasma
Arts et al. “penetration depth method” Kn >>1
Arts, Utriainen, Puurunen, Kessels, Knoops, J. Phys. Chem. C,
123 (2019) 27030-27035; DOI:10.1021/acs.jpcc.9b08176
Van de Poll et al., Appl. Phys. Lett. 123 (2023) 182902;
DOI:10.1063/5.0168768
“Recombination probabilities of oxygen radicals at
atmospheric pressure are extracted to be
4×10−4 for SiO2 and 6×10−5 for TiO2.”
Just out! Published Online: 31 October 2023
Kn ~ 1
4.
21. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Open-science-enabled quantitative comparison of
diffusion–reaction and ballistic transport–reaction models
Järvilehto, Velasco, Yim, Gonsalves,
Puurunen, Phys. Chem. Chem. Phys.
25 (2023) 22952-22964;
DOI:10.1039/D3CP01829F 1. Penetration depth: DR < BTR model
2. Slope: DR > BTR model
: DReaM-ALD, Machball
3.
Kn >>1
4.
DR BTR
22. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
More of Open Science? ALD saturation profile database?
https://zenodo.org/communities/ald-saturation-profile-open-data
Open Data makes the reuse of data easier
– and more reliable
● Example: Aguinsky et al., Solid State Electronics 201
(2023) 108584;
https://doi.org/10.1016/j.sse.2022.108584
4.
?
3
23. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Investigation of unwanted CVD component in ALD
Monte Carlo simulations
Cremers, Puurunen, Dendooven, Conformality in atomic layer
deposition: Current status overview of analysis and modelling, Appl.
Phys. Rev. 6 (2019) 021302; DOI:10.1063/1.5060967
1. Reactant decomposition (non-
saturating reaction with self)
modelled
2. Mixing of reactants in gas
phase?
No systematic experimental
investigations published (?)
time
4.
24. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
● Pristine territory for scientific
advances
● Measurement of experimental
saturation profiles
● Modelling of saturation profiles
○ Model development
○ Kinetic parameter extraction
● Open Science
→ global collaboration
○ Zenodo.org saturation profile community
co-curator? (academic?)
Outlook – what’s next?
5.
Open Science
25. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Acknowledgements
All collaborators throughout the years
5.
Catalysis group at Aalto University (May 2023)
26. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Extra materials in this slideset, with links
1. Publications from http://pillarhall.com/references.htm, accessed 7.11.2023
2. Fundamentals of atomic layer deposition: an introduction (“ALD 101”) presentation at ALD
2021
3. ALD Stories Episode 14: Understanding Conformality with Riikka Puurunen
4. Introductory ALD chapter in Kirk-Othmer Encyclopedia of Chemical Technology (many
creative commons images)
5. On the fundamentals of ALD: the importance of getting the picture right, by Riikka L.
Puurunen and J. Ruud van Ommen
6. Video derivation of the well-known Langmuir equation
7. Järvilehto et al. presentation at ALD 2023
8. Records on how research code was published to GitHub and linked to Zenodo.org
9. ALD contents at openlearning.aalto.fi
10. Virtual Project on the History of ALD (VPHA)
11. Abstract of this invited talk
extras
27. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Scientific articles created with PillarHall®
microscopic lateral high-aspect-ratio (LHAR)
test structures
From http://pillarhall.com/references.htm, accessed 7.11.2023
Simulation of conformality of ALD growth inside lateral channels: comparison
between a diffusion–reaction model and a ballistic transport–reaction model,
Jänis Järvilehto, Jorge A. Velasco, Jihong Yim, Christine Gonsalves and Riikka
L. Puurunen, ChemRxiv. Cambridge: Cambridge Open Engage, 2023,
https://doi.org/10.26434/chemrxiv-2023-bnzgr
3D Thin Film Metrology without Cross-Sectional Sampling (2023), Anish Philip,
Mikko Utriainen, Thomas Werner, Pasi Hyttinen, Jaakko Saarilahti, Jussi
Kinnunen, Feng Gao, IEEE International Interconnect Technology Conference
(IITC) and IEEE Materials for Advanced Metallization Conference
(MAM)(IITC/MAM), https://doi.org/10.1109/IITC/MAM57687.2023.10154886
Characterization of PillarHall test chip structures using a reflectometry
technique, Aleksandr Danilenko et al 2023 Meas. Sci. Technol. 34 094006,
http://urn.fi/URN:ISBN:978-952-64-1265-8
Atomic/molecular layer deposited crystalline metal-organic thin films based on
low-valent metals, Jenna Multia, Aalto University publication series Doctoral
Theses 69/2023, http://urn.fi/URN:ISBN:978-952-64-1265-8
Molecular layer deposition of alucone in high aspect ratio trenches: The effect of
TMA outgassing on step-coverage, H. Jain, M. Creatore and P. Poodt, J. Vac.
Sci. Technol.A 41 (2023), 012401, https://doi.org/10.1116/6.0002249
Conformality of atomic layer deposition in microchannels: impact of process
parameters on the simulated thickness profile, J. Yim, E. Verkama, J. Velasco,
K. Arts and R.L. Puurunen, Phys. Chem. Chem. Phys. (2022),
https://doi.org/10.1039/D1CP04758B
Optical metrology of 3D thin film conformality by LHAR chip assisted method M.
Utriainen, K. Saastamoinen, H. Rekola, O.M.E. Ylivaara, R.L. Puurunen and
P.Hyttinen, Proceedings Volume 12008, Photonic Instrumentation Engineering
IX; 120080D (2022), Event: SPIE OPTO, 2022, San Francisco, California,
United States, https://doi.org/10.1117/12.2609643
Conformality and the role of ions during plasma-assisted atomic layer
deposition, K. Arts (2021), PhD thesis 1 (Research TU/e/ Graduation TU/e),
Applied Physics and Science Education, Eindhoven University of Technology,
20210915_CO_Arts_hf.pdf (tue.nl)
Impact of Ions on Film Conformality and Crystallinity during Plasma-Assisted
Atomic Layer Deposition of TiO2, K. Arts, H. Thepass, M.A. Verheijen, R.L.
Puurunen, W.M.M. Kessels and H.C.M. Knoops, Chem. Mater. (2021),
https://doi.org/10.1021/acs.chemmater.1c00781
Saturation profile measurement of atomic layer deposited film by X-ray
microanalysis on lateral high-aspect-ratio structure, E. Haimi, O.M.E. Ylivaara,
J. Yim and R.L. Puurunen, Appl. Surf. Sci. Advances 5 (2021), 100102,
https://doi.org/10.1016/j.apsadv.2021.100102
Oxygen Recombination Probability Data for Plasma-Assisted Atomic Layer
Deposition of SiO2 and TiO2, K. Arts, S. Deijkers, R.L. Puurunen, W.M.M.
Kessels and H.C.M. Knoops, J. Phys. Chem. C 2021, 125, 15, 8244–8252,
https://doi.org/10.1021/acs.jpcc.1c01505
Saturation Profile Based Conformality Analysis for Atomic Layer Deposition:
Aluminum Oxide in Lateral High-Aspect-Ratio Channels, J. Yim, O.M.E.
Ylivaara, M. Ylilammi, V. Korpelainen, E. Haimi, E. Verkama, M. Utriainen and
R. L. Puurunen, Phys. Chem. Chem. Phys. 22 (2020), 23107,
https://doi.org/10.1039/D0CP03358H
Two-Step Approach for Conformal Chemical Vapor-Phase Deposition of Ultra-
Thin Conductive Silver Films, S. Wack, P.L. Popa, N. Adjeroud, C. Vergne and
R. Leturcq, ACS Appl. Mater. Interfaces 12 (2020), 32, 36329–36338,
https://doi.org/10.1021/acsami.0c08606
Evidence for low-energy ions influencing plasma-assisted atomic layer
deposition of SiO2: impact on the growth per cycle and wet etch rate, K. Arts,
J.H. Deijkers, T. Faraz, R.L. Puurunen, W.M.M. (Erwin) Kessels and H.C.M.
Knoops, Appl. Phys. Lett. 117 (2020), 031602,
https://doi.org/10.1063/5.0015379
Film Conformality and Extracted Recombination Probabilities of O Atoms during
Plasma-Assisted Atomic Layer Deposition of SiO2, TiO2, Al2O3, and HfO2, K.
Arts, M. Utriainen, R. L. Puurunen, W. M. M. Kessels, H. C. M. Knoops, J. Phys.
Chem. C 123 (2019), 44, 27030-27035,
https://pubs.acs.org/doi/10.1021/acs.jpcc.9b08176
ToF-SIMS 3D Analysis of Thin Films Deposited in High Aspect Ratio Structures
via Atomic Layer Deposition and Chemical Vapor Deposition, A. M. Kia, N.
Haufe, S. Esmaeili, C. Mart, M. Utriainen, R. L. Puurunen, W. Weinreich,
Nanomaterials 9 (2019) art. 1035; https://doi.org/10.3390/nano9071035
Surface-Inhibiting Effect in Chemical Vapor Deposition of Boron–Carbon Thin
Films from Trimethylboron, L. Souqui, H. Högberg and H. Pedersen, Chem.
Mater. 31 (2019) 5408-5412; https://doi.org/10.1021/acs.chemmater.9b0049
Sticking probabilities of H2O and Al(CH3)3 during atomic layer deposition of
Al2O3 extracted from their impact on film conformality, K. Arts, V. Vandalon,
R.L. Puurunen, M. Utriainen, F. Gao, W.M.M. Kessels, H.C. Knoops, J. Vac. Sci.
Technol. A 37 (2019) art. 030908; https://doi.org/10.1116/1.5093620
Conformality in atomic layer deposition: current status overview of analysis and
modelling, V. Cremers, R.L. Puurunen, J. Dendooven, Appl. Phys. Rev. 6
(2019) art. 021302; https://doi.org/10.1063/1.5060967
Modeling growth kinetics of thin films made by atomic layer deposition in lateral
high-aspect-ratio structures, M. Ylilammi, O. M. E. Ylivaara, R. L. Puurunen, J.
Appl. Phys. 123 (2018) art. 205301 (8 pages).
https://doi.org/10.1063/1.5028178
Influence of ALD temperature on thin film conformality: Investigation with
microscopic lateral high-aspect-ratio structures, R. L. Puurunen, F. Gao,
Proceedings of the International Baltic Conference on Atomic Layer Deposition,
2-4 Oct 2016, St. Petersburg, Russia. Electronically published in IEEE Xplore,
http://ieeexplore.ieee.org/document/7886526/
Nucleation and Conformality of Iridium and Iridium Oxide Thin Films Grown by
Atomic Layer Deposition, M. Mattinen, J. Hämäläinen, F. Gao, P. Jalkanen, K.
Mizohata, J. Räisänen, R. L. Puurunen, M. Ritala, M. Leskelä, Langmuir 32
(2016) 10559, http://dx.doi.org/10.1021/acs.langmuir.6b03007
Microscopic silicon-based lateral high-aspect-ratio structures for thin film
conformality analysis, F. Gao, S. Arpiainen, R. L. Puurunen, J. Vac. Sci.
Technol. A 33 (2015) 010601, http://dx.doi.org/10.1116/1.4903941
extras
28. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
https://youtu.be/xOYrCjcVTzA?si=1djvKC
Gx4AkFfzoU
(INVITED) Fundamentals of atomic layer
deposition: an introduction (“ALD 101”)
ABSTRACT:
Atomic layer deposition (ALD) has become of global importance
as a processing technology for example in semiconductor device
fabrication, and its application areas are continuously expanding.
The significance of ALD was highlighted e.g. by the recent
(2018) Millennium Technology Prize. Tens of companies are
offering ALD tools, and thousands of people are involved in ALD
R&D globally. A continuous need exists to educate new people
on the fundamentals of ALD.
While ALD for manufacturing may be regarded mature, as a
scientific field, ALD—in the author’s view—is developing. For
example, understanding of the early history of ALD is evolving,
related to the two independent inventions of ALD under the
names Atomic Layer Epitaxy in the 1970s and Molecular
Layering in the 1960s [1-4]. Also, significantly varying views exist
in the field related to the description and meaningfulness of even
some core ALD concepts [5].
<continues…>
extras
29. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Back to Basics: Understanding Conformality with Riikka Puurunen – ALD Stories Ep. 14
https://beneq.com/en/podcasts/
https://youtu.be/icb1xEf4eCQ?si=KshALwIrCDAk-vxL
extras
30. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Abstract: Atomic layer deposition (ALD) is a gas-phase method to grow layers of
solid materials with subnanometer precision. It has been invented independently in
the Soviet Union in the 1960s under the name molecular layering, and in the
1970s in Finland under the name atomic layer epitaxy. ALD relies on alternatingly
exposing a surface to gaseous reactants—separated by a purge step—that react
in a self-terminating manner. This article introduces the fundamentals of the
surface chemistry of ideal ALD, including saturating and irreversible reactions,
growth per cycle, monolayer concepts relevant to ALD, typical surface reaction
mechanisms, saturation-limiting factors, growth modes, area-selective ALD,
growth kinetics, and conformality. It also discusses typical deviations from ideal
ALD. Over the years, many different ALD process chemistries have been
developed. A range of reactor systems is available, depending on the type of
substrate and required productivity. ALD is broadly applicable in practice since it
couples nanoscale precision with a good scalability and can be used to deposit a
large variety of materials. In recent years, the interest in ALD has been growing
strongly. The most important sector regarding commercial applications of ALD is
currently the semiconductor industry.
Van Ommen, Goulas,
Puurunen,
“Atomic layer
deposition” in
Kirk-Othmer
Encyclopedia of
Chemical Technology,
2021,
https://doi.org/10.1002/0
471238961.koe00059
Many images in Wikimedia Commons
extras
31. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
extras
● https://www.slideshare.net/RiikkaPuurunen/on-the-fundamentals-
of-ald-the-importance-of-getting-the-picture-right-by-puurunen-
and-van-ommen
● https://youtu.be/jqm_wf49WwM
● https://aalto.cloud.panopto.eu/Panopto/Pages/Viewer.aspx?id=13
ed854b-5df8-4d37-8ff1-ac0d00dde319
Title: On the fundamentals of ALD: the
importance of getting the picture right
Authors: Riikka L. Puurunen and J. Ruud
van Ommen
Session: Precursors and Chemistry:
Simulation, Modeling, and Theory of ALD
33. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
● https://aalto.cloud.panopto.
eu/Panopto/Pages/Viewer.a
spx?id=0fec7dbe-fedf-
41de-a576-b06901010532
Article since then published:
Järvilehto, Velasco, Yim, Gonsalves, Puurunen,
Simulation of conformality of ALD growth inside
lateral channels: comparison between a diffusion–
reaction model and a ballistic transport–reaction
model, Phys. Chem. Chem. Phys. 25 (2023) 22952-
22964; DOI:10.1039/D3CP01829F
extras
34. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Records on how research code was published to GitHub
and linked to Zenodo.org
The Catalysis research group has published its first-ever open code! Coined DReaM-ALD, the recently
published Matlab script provides an implementation of a diffusion–reaction model developed by Ylilammi et al.
(J. Appl. Phys. 123, 205301 (2018), DOI: 10.1063/1.5028178). The model simulates atomic layer deposition in
high-aspect-ratio structures and generates saturation profiles, which show how the film thickness evolves with
penetration into the structure. This Matlab implementation was originally written by Emma Verkama in 2019 by
request of Prof. Riikka Puurunen, and the code was later published by Jänis Järvilehto. In addition to Github,
the code was also made available on Zenodo.
There was a significant delay (~3 years) between the creation and publication of the code. As there was no
prior history of open code in the group, the barrier to publication was relatively high. Questions, such as…
Where should we publish the code? What kind of information would be useful for a potential user? How does
the process work in general? Where do I click???
…may arise. While the best practices may seem obvious to a software engineer, generating research code
can be a messy affair in other fields. …
https://blogs.aalto.fi/catprofopen/2023/04/12/catalysis-
research-group-publishes-diffusion-reaction-model-code/
12.04.2023 Written by Jänis Järvilehto
https://youtu.be/ksxAIaytv68?si=qw
Edi47Vr6BAFhti
extras
35. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
ALD contents at openlearning.aalto.fi
https://openlearni
ng.aalto.fi/course/
view.php?id=100
extras
36. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Scientific journal articles from VPHA:
1. Essay: R. L. Puurunen, "A Short History of Atomic Layer Deposition: Tuomo Suntola's Atomic Layer Epitaxy", Chemical
Vapor Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012. Open Access.
2. Essay: A. A. Malygin, V. E. Drozd, A. A. Malkov, V. M. Smirnov: "From V. B. Aleskovskii’s "Framework" Hypothesis to
the Method of Molecular Layering/Atomic Layer Deposition", Chemical Vapor Deposition 21 (2015) 216-240. DOI:
10.1002/cvde.201502013.
3. Review article: “Recommended reading list of early publications on atomic layer deposition—Outcome of the “Virtual
Project on the History of ALD””, Esko Ahvenniemi, Andrew R. Akbashev, Saima Ali, Mikhael Bechelany, Maria
Berdova, Stefan Boyadjiev, David C. Cameron, Rong Chen, Mikhail Chubarov, Veronique Cremers, Anjana Devi,
Viktor Drozd, Liliya Elnikova, Gloria Gottardi, Kestutis Grigoras, Dennis M. Hausmann, Cheol Seong Hwang, Shih-Hui
Jen, Tanja Kallio, Jaana Kanervo, Ivan Khmelnitskiy, Do Han Kim, Lev Klibanov, Yury Koshtyal, A. Outi I. Krause,
Jakob Kuhs, Irina Kärkkänen, Marja-Leena Kääriäinen, Tommi Kääriäinen, Luca Lamagna, Adam A. Łapicki, Markku
Leskelä, Harri Lipsanen, Jussi Lyytinen, Anatoly Malkov, Anatoly Malygin, Abdelkader Mennad, Christian Militzer, Jyrki
Molarius, Małgorzata Norek, Çağla Özgit-Akgün, Mikhail Panov, Henrik Pedersen, Fabien Piallat, Georgi Popov, Riikka
L. Puurunen, Geert Rampelberg, Robin H. A. Ras, Erwan Rauwel, Fred Roozeboom, Timo Sajavaara, Hossein Salami,
Hele Savin, Nathanaelle Schneider, Thomas E. Seidel, Jonas Sundqvist, Dmitry B. Suyatin, Tobias Törndahl, J. Ruud
van Ommen, Claudia Wiemer, Oili M. E. Ylivaara, Oksana Yurkevich, Journal of Vacuum Science and Technology A
35 (2017) 010801 (13 pages). DOI: 10.1116/1.4971389. Open access.
4. Proceedings article: R. L. Puurunen, "Learnings from an Open Science Effort: Virtual Project on the History of ALD",
ECS Transactions 86(6) (2018) 3-17; doi:10.1149/08606.0003ecst. Open access preprint, DOI: 10.1149/osf.io/exyv3.
https://vph-ald.com/ (materials available as of November 2023, no new activities to come)
extras
37. Puurunen - invited, AVS 69, Nov 5-10, 2023, Portland, Oregon
Recent Progress in Analysis of the Conformality of Films
by Atomic Layer Deposition
Author: Prof. Riikka Puurunen, Aalto University, Finland
Topic: Atomic Scale Processing Mini-Symposium, Session: AP7+TF: Novel ALD/CVD Precursors and Processes for High Aspect Ratio Architectures
Invited Paper: Yes
ABSTRACT. Conformality is a fundamental characteristic of atomic layer deposition (ALD) thin film growth technique. “Conformal” film refers to a film that covers all
surfaces of a complex three-dimensional substrate with everywhere the same thickness and properties. ALD - invented independently by two groups in 1960s and
1970s - has since late 1990s been transformational in semiconductor technology. Apart from semiconductors, conformal ALD films find applications and interest in
widely varied fields such as microelectromechanical systems, pharmaceutical powder processing, optical coatings, battery technologies and heterogeneous
catalysts.
Conformality follows directly from the “ideal ALD” principles: growth of material through the use of repeated separate self-terminating (i.e., saturating and irreversible)
gas-solid reactions of at least two compatible reactants on a solid surface. Obtaining conformality in practice is not self-evident, however. Reasons for deviation from
conformality are multiple, ranging from mass transport limitations to slow reaction kinetics and various deviations from ideal ALD (e.g., by-product reactivity or a
continuous chemical vapor deposition (CVD) component through reactant decomposition or insufficient purging). Incomplete conformality can also be intentional: a
saturation profile inside a feature can be exposed, to enable an analysis of kinetic parameters of the reactions.
This invited talk will explore recent progress especially by the author and collaborators in understanding ALD conformality and kinetics, obtained via experiments and
simulations. Experiments have been made with the recently commercialized (chipmetrics.com) silicon-based PillarHallTM lateral HAR test chips (channel height ~500
nm) and spherical mesoporous high-surface-area materials (average pore diameter ~10 nm, sphere diameter ~1 mm). Simulations are presented for 1d feature-
scale models and optionally a recently developed 3d code for spheres. Two codes are available on GitHub: DReaM-ALD (diffusion-reaction model, DRM) and
Machball (ballistic transport-reaction model, BTRM). Often it is assumed that diffusion during an ALD process in HAR features is by Knudsen diffusion and free
molecular flow conditions prevail (Kn >>1). If so, a characteristic “fingerprint saturation profile” can be obtained, and the slope method (derived for DRM-ALD-Arts,
GitHub) can be used to back-extract the lumped sticking coefficient. When diffusion is in the transition flow (Kn ~1) or continuum flow (Kn<<1), the shape of the
saturation profile depends on process conditions and the slope method is not applicable.
extras
Arts: t is the dose time of co-reactant, seconds
푡푡
t50% Dose time for 50%-saturation at entrance of high-aspect -ratio structure (s)
Cremers et al. Fig. 24: Simulated thickness profile of a hole structure with EAR of 50:1, in the case of an ALD process with a CVD contribution, based on irreversible reactions. The schematic s-plots represent the sticking probability s as a function of the surface coverage θ assuming the irreversible Langmuir-type adsorption with varying initial sticking coefficients s0 = 0.1 (a) and 0.01 (b) and reaction probability of the CVD contribution preaction = 0.0002. For each case, the deposition profiles are shown for a hole structure without (middle) or with (right) a terminating bottom surface. The normalized exposure required to obtain the different thickness profiles is given by black line: 700, blue line: 1400, red line: 2100, and green line: 2800.
Atomic Scale Processing Mini-Symposium Room A107-109 - Session AP+PS+TF-WeM Plasma Deposition and ALD Processes for Coatings and Thin Films Moderators: Silvia Armini, IMEC, Belgium, Jessica Kachian, Intel Corporation
8:00-8:40
Atomic Scale Processing Mini-Symposium Room A107-109 - Session AP+PS+TF-WeM Plasma Deposition and ALD Processes for Coatings and Thin Films Moderators: Silvia Armini, IMEC, Belgium, Jessica Kachian, Intel Corporation
8:00-8:40