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 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
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.
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
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)
"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.
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.
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.
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 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
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.
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
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)
"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.
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.
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.
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
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.
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.
TRANSPARENT ELECTRONICS
Abstract: Transparent electronics is an emerging science and technology field focused on producing ‘invisible’ electronic circuitry and opto-electronic devices.
Applications include consumer electronics, new energy sources, and transportation; for example, automobilewindshields could transmit visual information to the driver. Glass in almost any setting could also double as an electronic device, possibly improving security systems or offering transparent displays. In a similar vein, windows could be used to produce electrical power. Other civilian and military applications in this research field include realtime wearable displays.
As for conventional Si/III–V-based electronics, the basic device structure is based on semiconductor junctions and transistors. However, the device building block materials, the semiconductor, the electric contacts, and the ielectric/passivation layers, must now be transparent in the visible –a true challenge! Therefore, the first scientific goal of this technology must be to discover,understand, and implement transparent high-performance electronic materials. The second goal is their implementation and evaluation in transistor and circuit structures.
The electronics during the past 10 years, the classes of materials available for transparent electronics applications have grown dramatically. Historically, this area was dominated by transparent conducting oxides (oxide materials that are both electrically conductive and optically transparent) because of their wide use in antistatic coatings, touch display panels, solar cells, flat panel displays, heaters, defrosters, ‘smart windows’ and optical coatings. All these applications use transparent conductive oxides as passive electrical or optical coatings. The field of transparent conducting oxide (TCO) materials has been reviewed and many treatises on the topic are available. However, more recently there have been tremendous efforts to develop new active materials for functional transparent electronics. These new technologies will require new materials sets, in addition to the TCO component, including conducting, dielectric and semiconducting materials, as well as passive components for full device fabrication.
COMBINING OPTICAL TRANSPARENCY WITH ELECTRICAL CONDUCTIVITY
Transparent conductors are neither 100% optically transparent nor metallically conductive. From the band structure point of view, the combination of the two properties in the same material is contradictory: a transparent material is an insulator which possesses completely filled valence and empty conduction bands; whereas metallic conductivity appears when the Fermi level lies within a band with a large density of states to provide high carrier concentration. Efficient transparent conductors find their niche in a compromise between a sufficient transmission within the visible spectral range and a moderate but useful in practice electrical conductivity.
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
Light-emitting diodes (LEDs) are solid-state light sources increasingly used in general illumination. Advanced properties, such as energy efficiency and long lifetime, are promoting LED replacement over traditional lamp-based solutions. Features like small size and ease of control are also appreciated among the lighting community. Smart lighting with advanced control has attracted particular attention recently due to the increased energy savings via added intelligence. Besides the environmental reasons, the economic impact of LED lighting technology development is significant, with solid growth predicted for the energy-efficient lighting market.
This thesis addresses high-power LED lighting technology development at four different levels. At the component, module and luminaire levels, the research concentrates on thermal management, which is considered one of the main factors for reliability and performance. The research focus is on reducing the thermal resistance of the high-power LED structure. This is achieved with thermal vias through the insulation layer of the substrate under the heat source. As a result, a total thermal resistance reduction of 10–55% is shown in comparison with commercial substrate technologies.
Energy efficiency is considered the measure of the achievements at the luminaire and system levels. The topic is studied with a pedestrian street lighting installation in a real use environment. Case examples of dimming the street lighting according to natural light levels and pedestrian presence revealed power savings of more than 40% with smart control.
Can we just imagine of having a TV which can be rolled up? Wouldn’t you like to be able to read off the screen of your laptop in direct sunlight? Your mobile phone battery to last much, much longer? Or your next flat screen TV to be less expensive, much flatter, and even flexible? Well, now it is possible by an emerging technology based on the revolutionary discovery that, light emitting, fast switching diode could be made from polymers as well as semiconductors.OLED
Thermatic simulation platform for nano materials design in kistKIST
This slides introduce the web based thematic materials design platform developed in the Computational Science Center at KIST. This platform is to provide an easy-to-use materials simulation environment where people can perform various advanced simulations using the workflows very similar to those of the real experiment. These platforms were designed to reduce the entrance barrier to the complicated materials simulation using the high performance cluster computer. We are anticipating that these platforms will become robust R&D tool to design novel (nano) materials.
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
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.
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.
TRANSPARENT ELECTRONICS
Abstract: Transparent electronics is an emerging science and technology field focused on producing ‘invisible’ electronic circuitry and opto-electronic devices.
Applications include consumer electronics, new energy sources, and transportation; for example, automobilewindshields could transmit visual information to the driver. Glass in almost any setting could also double as an electronic device, possibly improving security systems or offering transparent displays. In a similar vein, windows could be used to produce electrical power. Other civilian and military applications in this research field include realtime wearable displays.
As for conventional Si/III–V-based electronics, the basic device structure is based on semiconductor junctions and transistors. However, the device building block materials, the semiconductor, the electric contacts, and the ielectric/passivation layers, must now be transparent in the visible –a true challenge! Therefore, the first scientific goal of this technology must be to discover,understand, and implement transparent high-performance electronic materials. The second goal is their implementation and evaluation in transistor and circuit structures.
The electronics during the past 10 years, the classes of materials available for transparent electronics applications have grown dramatically. Historically, this area was dominated by transparent conducting oxides (oxide materials that are both electrically conductive and optically transparent) because of their wide use in antistatic coatings, touch display panels, solar cells, flat panel displays, heaters, defrosters, ‘smart windows’ and optical coatings. All these applications use transparent conductive oxides as passive electrical or optical coatings. The field of transparent conducting oxide (TCO) materials has been reviewed and many treatises on the topic are available. However, more recently there have been tremendous efforts to develop new active materials for functional transparent electronics. These new technologies will require new materials sets, in addition to the TCO component, including conducting, dielectric and semiconducting materials, as well as passive components for full device fabrication.
COMBINING OPTICAL TRANSPARENCY WITH ELECTRICAL CONDUCTIVITY
Transparent conductors are neither 100% optically transparent nor metallically conductive. From the band structure point of view, the combination of the two properties in the same material is contradictory: a transparent material is an insulator which possesses completely filled valence and empty conduction bands; whereas metallic conductivity appears when the Fermi level lies within a band with a large density of states to provide high carrier concentration. Efficient transparent conductors find their niche in a compromise between a sufficient transmission within the visible spectral range and a moderate but useful in practice electrical conductivity.
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
Light-emitting diodes (LEDs) are solid-state light sources increasingly used in general illumination. Advanced properties, such as energy efficiency and long lifetime, are promoting LED replacement over traditional lamp-based solutions. Features like small size and ease of control are also appreciated among the lighting community. Smart lighting with advanced control has attracted particular attention recently due to the increased energy savings via added intelligence. Besides the environmental reasons, the economic impact of LED lighting technology development is significant, with solid growth predicted for the energy-efficient lighting market.
This thesis addresses high-power LED lighting technology development at four different levels. At the component, module and luminaire levels, the research concentrates on thermal management, which is considered one of the main factors for reliability and performance. The research focus is on reducing the thermal resistance of the high-power LED structure. This is achieved with thermal vias through the insulation layer of the substrate under the heat source. As a result, a total thermal resistance reduction of 10–55% is shown in comparison with commercial substrate technologies.
Energy efficiency is considered the measure of the achievements at the luminaire and system levels. The topic is studied with a pedestrian street lighting installation in a real use environment. Case examples of dimming the street lighting according to natural light levels and pedestrian presence revealed power savings of more than 40% with smart control.
Can we just imagine of having a TV which can be rolled up? Wouldn’t you like to be able to read off the screen of your laptop in direct sunlight? Your mobile phone battery to last much, much longer? Or your next flat screen TV to be less expensive, much flatter, and even flexible? Well, now it is possible by an emerging technology based on the revolutionary discovery that, light emitting, fast switching diode could be made from polymers as well as semiconductors.OLED
Thermatic simulation platform for nano materials design in kistKIST
This slides introduce the web based thematic materials design platform developed in the Computational Science Center at KIST. This platform is to provide an easy-to-use materials simulation environment where people can perform various advanced simulations using the workflows very similar to those of the real experiment. These platforms were designed to reduce the entrance barrier to the complicated materials simulation using the high performance cluster computer. We are anticipating that these platforms will become robust R&D tool to design novel (nano) materials.
Slot waveguide is a specific light-guiding structure with a property to enhance the optical field in a nanometer scale void of low refractive index (RI) material embedded between higher RI material rails. Typically, slot waveguides have been fabricated from high refractive index inorganic dielectrics or semiconductors, such as silicon or silicon nitride, and they operate in the near infrared (NIR) wavelength region. The slot waveguide structure enables strong light–ambient interaction, a property that is preferred, for instance, in integrated optical sensors utilizing the change of the refractive index as the sensing transduction signal. In this thesis; the characteristic properties of slot waveguides were studied as regards their usage in polymer platforms.
The polymers are transparent in the visible and NIR wavelength region. In this work, the operation of the polymer slot waveguide was demonstrated for both visible and NIR wavelengths by using Young interferometer devices. For the device fabrication, the ultraviolet (UV) assisted nanoimprint moulding method was utilized. The emphasis was to demonstrate that the high performance slot waveguide sensor configuration is attainable with a simple low-cost fabrication method, enabling usage as disposable sensors.
The bulk refractive index (RI) response of the slot waveguide-based Young interferometer was characterized with glucose – deionized water solutions. With this arrangement, an ambient RI change of 6.4×10-6 was measured. In the slot Young interferometer structure, both waveguide arms of the interferometer detect the bulk RI changes of the ambient material. This novel structure was proved to effectively compensate for thermo-optic originated response drift while maintaining high sensitivity against bulk RI change.
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.
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) ...
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
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/
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.
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
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
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.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptxRASHMI M G
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
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
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
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/
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
1. History of
Atomic Layer Deposition
Tutorial at 14th International Conference on
Atomic Layer Deposition (AVS-ALD 2014, Kyoto, Japan)
Dr. Riikka Puurunen
VTT Technical Research Centre of Finland
2. 2Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Two historical routes to film growth in
alternating, saturating gas-solid reactions
Atomic Layer Epitaxy
Molecular Layering
3. 3Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Atomic Layer Epitaxy
Finland
4. 4Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Background of the invention of
Atomic Layer Epitaxy (ALE)
Humidity sensor by
Suntola/VTT to Vaisala
Demonstrator 1973
40 years HUMICAP® in
2013
Company Instrumentarium looking for new products
Suntola invited to ”suggest and find out something”
Suntola with small humidity team moved to Instrumentarium 1974
Suntola on Vaisala’s Youtube video
5. 5Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Early 1974: market need/technology mapping
study
Sensor technologies diversified into small
unities, difficult to build a technology platform
on such basis
However: a display, preferably small, is
needed in most instruments
Suntola’s proposed to work on:
ion-selective sensors
flat panel displays
“I am still
confusedbut at
a higher level.”
Let’s go ahead!
Let’s develop
an electroluminescent
flat panel display
…nobody has done it
yet
6. 6Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
ZnS: quality of existing thin films insufficient
Electroluminescence requires controlled crystallinity
Deposition () not sufficient
Growth () needed
Atomic Layer Epitaxy
Epitaxy from Greek:
Epi taxis,
on-arrangement
7. 7Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
First ALE experiments with elemental Zn and S
First ALE patent applied November 29, 1974
Images by Suntola
8. 8Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
ALE patent granted
in 26 countries
In prior art study, closest found
a German patent from mid-50s
saturation was missing from
this patent
Hearings related to the patent
were organized in several
countries, including The United
States, Japan, and The Soviet
Union
9. 9Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Switch to flow reactor & compound reactants,
EL demo
High-vacuum-system would not be
production worthy towards flow
apparatus and exchange reactions
Zn + Sx
Successful
ZnCl2 + Sx
No success
ZnCl2 + Sx + H2
No success
ZnCl2 + H2S
”That’s it”! (by Pakkala)
ALE-EL development
sold to Lohja Oy
in 1978
2nd ALE patent,
Feb 28, 1979Sven Lindfors and a flow-reactor
10. 10Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
SID conference 1980: first publication & demo
Society for Information Display (SID), San Diego, California, April 29 to May 1, 1980
Revolutionary EL display
3000-4000 product requests
Suntola, 2014:
“we had neither the
production line constructed
nor the product developed”
“What a tragedy, wasted
marketing”
demand for flat panel
displays confirmed
1980 SID Outstanding Paper Award for
the EL work – Suntola, Antson, Lindfors,
Pakkala, given in SID 1981.
11. 11Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
International Conference on Vapor Growth and
Epitaxy, 5 in San Diego, California
Suntola invited talk on Atomic Layer Epitaxy
Little scientific information available on the ALE grown material
Use of the term “epitaxy” for non-single-crystal thin films was
criticized
Prof Jun-ichi Nishizawa from Japan was among the participants,
realized the significance of ALE initiation of GaAs research in
Japan (“Molecular Layer Epitaxy”)
Nishizawa, MLE-GaAs in the 16th, (1984 International) Conference
on Solid State Devices and Materials, in Kobe, Japan, 1984
12. 12Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
ALE-EL pilot production in Lohja, Kunnarla
First real test: Helsinki-
Vantaa airport information
flight display boards, 1983
Al2O3-TiO2 nanolaminate
(”ATO”) chosen as the
dielectric
15 years in continuous
use, without a single
character module replaced
Dr. Ralf Graeffe & display board test
assembly, Helsinki-Vantaa airport
underground cave, 1983.
13. 13Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Production facilities built in Espoo 1983-1984
Production started gradually in 1985. Bought by Planar in 1990.
EL-production continues, operated by Beneq Oy since 2012
Photo: Tuomo Suntola
ALE-EL licenced to
France, in 1983,
500 x 500 mm2
substrates
14. 14Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Microchemistry Ltd. in 1987
Founded by Suntola as a
subsidiary of Neste Corporation
ALE-based solar panels
ALE to heterogeneous catalyst
• F-120 reactor developed for own
use became the 1st commercial
ALD reactor
• “Catalyst work brought highly
desired chemistry expertise into
Microchemistry”
15. 15Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
ALE-1 conference, Prof. Niinistö, Espoo/Helsinki
The first International Symposium on Atomic Layer Epitaxy, June 11-13, 1990
Ms. Erja Nykänen, Helsinki University of Technology
(HUT); Prof. Konagai, Tokyo Institute of Technology;
Dr. Tuomo Suntola, Microchemistry Ltd.; Prof. Niinistö,
HUT; Prof. Nishizawa, Semiconductor Laboratory,
Sendai; Prof. Bedair, North Carolina University.
16. 16Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
MRS 1994 Annual Meeting in Boston
First-ever exhibition booth of ALE
Suntola invited talk:
ALE for Semiconductor
Applications
interest in ALE from
semiconductor industry
and equipment
manufacturers
17. 17Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
1998, Suntola left behind the active role in ALE (ALD)
2004 The European SEMI Award
“Honoring the Pioneer in
Atomic Layer Deposition Techniques ...
that paved the way for the development
of nanoscale semiconductor devices“
2014: Suntola continues as a board member of Picosun Oy, the
chairman of the Physics Foundations Society and a board
member and a frequent lecturer in the Finnish Society for Natural
Philosophy.
18. 18Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Molecular Layering
Mолекулярное Hаслаивание
USSR/Russia Professor
Valentin Borisovich
Aleskovskii
∗ 03.06.1912
† 29.01.2006
Professor
Stanislav Ivanovich
Koltsov
∗ 30.08.1931
† 26.05.2003
Rector x 2
Corresponding member of the
USSR Academy of Sciences
(now the Russian Academy of Sciences)
19. 19Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Aleskovskii 1952:
Thesis for habilitation degree (doktor nauk, ”2nd thesis”)
”Matrix hypothesis and way of synthesis of some active
solid compounds”,
Leningrad Lensoviet Institute of Technology
The matrix hypothesis (or skeleton hypothesis) enabled
two basic ways of transforming a solid to another:
(1) substituting atoms in the skeleton and (2) reactions of
functional groups.
Later, further work on (1) led to Destruction-Epitaxial
Transformations method (A.P. Dushina) and on (2) to
Molecular Layering (S. I. Koltsov, 1971)
20. 20Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Scientific and Technical Conference, Leningrad
abstract books available, Publisher: Gozkhimiizdat
1963: Koltsov:
Synthesis of multilayered
inorganic polymers
April 1965: Aleskovskii, Koltsov:
Some characteristics of
molecular layering reactions
21. 21Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
2nd USSR conference on high temperature chemistry of
oxides, November 26-29, 1965, Leningrad, USSR
Shevjakov, A. M.; Kuznetsova,
G. N. and Aleskovskii, V. B.:
Interaction of titanium and
germanium tetrachlorides with
hydrated silica.
10 cycles TiCl4/H2O
Later, Koltsov: Preparation and
investigation of the products of
interaction between titanium
tetrachloride and silica gel. J.
Appl. Chem. USSR. 42, 975-979
1969
22. 22Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
ML thin films on planar substrates:
TiO2 and SiO2 on Si published in 1970
Sveshnikova, G. S., Kol'tsov, S.
I. & Aleskovskii, V. B.
Interaction of titanium
tetrachloride with hydroxylated
silicon surfaces
J. Appl. Chem. USSR., 43, 432-
434, 1970
[in English and in Russian]
Sveshnikova, G. V.; Kol'tsov, S. I. & Aleskovskii, V. B.
Formation of a silicon oxide layer of predetermined
thickness on silicon by the molecular layering method.
J. Appl. Chem. USSR, 43, 1155-1157, 1970
[in English and Russian]
23. 23Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Koltsov 1971: ”The ML Thesis”
Kol’tsov, S. I. Synthesis of solids by the Molecular Layering
Method, Doktor nauk thesis, Lensovet Leningrad
Technological Institute, 1971, 383 p. [In Russian]
Secrecy requirements relaxed in 2013
24. 24Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Author’s certificates in 1972, catalyst
preparation
A.N. Volkova, A.A. Malygin, S.I.
Kol’tsov, V.B. Aleskovskii: The
method of synthesis of Cr(III) and
P(V) oxide layers on the silicagel
surface (for catalytic
dehydrogenation,
dehydrocyclization and other
reactions)
http://patentdb.su/2-422446-
sposob-polucheniya-okisnogo-crill-
i-pv-sloya-na-poverkhnosti-
kremnezela.html
25. 25Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Drozd thesis 1978 – ”kandidat nauk” / PhD
Vacuum thin film reactor
with programmable unit
Diodes with ML dielectrics,
electrical characterization
Cr2O3
V2O5
TiO2
HfO2
ZrO2
Ta2O5
WO3
Nb2O5
MoO2
Oxide layer
composition
Layer
thickness
Barrier
height
Barrier
height Si-Me
26. 26Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Some other ML papers
(there are many, many more see the Kyoto VPHA posters #3, #4)
Aleskovskii, V. B., Chemistry and technology of solids. J. Appl. Chem.
USSR., 47, 2207-2217, 1974. [in English and in Russian] (review)
Yakovlev, S. V.; Malygin, A. A.; Kol'tsov, S. I.; Aleskovskii, V. B.;
Chesnokov, Yu. G. & Protod'yakonov, I. O. Mathematical model of
molecular layering with the aid of a fluidizided bed, J. Appl. Chem.
USSR, 52, 959-963, 1979. [in English and in Russian]
Tolmachev, V. A. Possibility of the use of a gravimetric method for
studying the process of molecular layering in disperse silica samples.
J. Appl. Chem. USSR., 55(6), 1298-1299, 1982. [in English and in
Russian] (in situ)
V. D. Ivin, R. M. Levit, A. A. Malkov, E. P. Smirnov. Interaction of
methane with the chlorinated surface of carbon fibers. J. Appl. Chem.
USSR. 1985, V. 58, № 3, P. 592-595. [in English and in Russian]
(growth of carbon)
27. 27Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Examples of applications using ML
(more info poster #3)
Adsorbents to stabilize
the device’s internal
environment during
storage and operation
Ceramics for X-ray tubes, ML to
decrease sintering temperature
Source: Prof Malygin’s
Aleskovskii 100-year presentation
28. 28Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
ALE-1 conference, June 11-13, 1990
The first International Symposium on Atomic Layer Epitaxy, Espoo/Helsinki
Dr. Drozd attended
Proceedings: Aleskovskii, V. B. & Drozd, V. E.
Acta Polytech. Scand., Chem. Technol. Ser., 1990, 195, 155-161
29. 29Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Ritala, M.,
Leskelä, M.
Nalwa, H. S. (Ed.)
Atomic Layer
Deposition
Handbook of Thin
Film Materials,
Academic Press,
2002, 1, 103-159
30. 30Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Puurunen, J. Appl. Phys 97(2005) 121301
Riikka’s ALD history activities as postdoc at IMEC
”.. Most of the publications
referred to in Table I have
been published in Soviet–
Russian journals, which
have been translated into
English. The overview of
Table I is meant to be
introductory, and it can by
no means be expected to be
complete.”
31. 31Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Virtual Project on the History of ALD
(VPHA)
VPHA set up to clarify open questions on the history of ALD
Carried out in atmosphere of Openness, Respect, Trust
Collect & read ALD literature until 1986.
Common literature list collected in the publicly accessible ALD-
history-evolving-file
VPHA open since: July 25, 2013, announced at ALD 2013
First publication: poster at Baltic ALD, May 12-13, Helsinki
At this AVS-ALD 2014 conference in Kyoto: two posters (#3, #4)
Work on-going
Everyone welcome to join!
32. 32Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Conclusion: two independent roots of ALD
(Riikka’s own current personal view)
Atomic Layer Epitaxy (ALE)
Initiated in industry,
originally for EL displays,
by people with semiconductor
physics background
Directed to industrial use of the
ALD
Very secret in the beginning,
only patent publications
Commercial reactors triggered
worldwide ALD activity in 1990s
Molecular Layering (ML)
Initiated in academia,
for broad goals,
by people with chemistry
background
Key: understanding ways of
modifying solids
Partly secret in the beginning,
broad variety of publications
Rich history in ALD, details
being unraveled in VPHA
33. 33Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Acknowledgements
Finnish history: Dr. Tuomo Suntola
USSR/Russian history: Prof. Anatoly Malygin & Prof. Victor Drozd
VPHA co-leadership: Dr. Jonas Sundqvist
VPHA: Jaan Aarik, Andrew R. Akbashev, Mikhael Bechelany, Maria Berdova,
David Cameron, Nikolai Chekurov, Victor E. Drozd, Simon D. Elliott, Gloria
Gottardi, Kestutis Grigoras, Marcel Junige, Tanja Kallio, Jaana Kanervo, Yury
Koshtyal, Marja-Leena Kääriäinen, Tommi Kääriäinen, Luca Lamagna, Anatoly
Malkov, Anatoly Malygin, Jyrki Molarius, Cagla Ozgit-Akgun, Henrik Pedersen,
Alexander Pyymäki Perros, Robin H. A. Ras, Fred Roozeboom, Timo Sajavaara,
Hele Savin, Thomas E. Seidel, Pia Sundberg, Jonas Sundqvist, Massimo
Tallarida, J. Ruud van Ommen, Thomas Wächtler, Claudia Wiemer, Oili M. E.
Ylivaara. Aziz Abdulagatov, Annina Titoff
Partly funded by the Academy of Finland’s
Finnish Centre of Excellence in Atomic Layer Deposition
34. 34Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Links and sources
Website of Virtual Project on the History of ALD (VPHA)
Being built at http://baldengineering.com/vpha.html
Contains (/will contain) links to all relevant VPHA material
2005 review with notions on ALD history:
J. Appl. Phys 97(2005) 121301
http://www.vtt.fi/inf/julkaisut/muut/2010/Puurunen.pdf
Suntola ALD webpage: http://www.sci.fi/~suntola/ald.html
Contains e.g. links to presentations
LinkedIn ALD History group:
https://www.linkedin.com/groups/ALD-History-5072051/about
Exhibition: 40 Years of ALD in Finland – Photos, Stories
In Espoo/Helsinki, traveled to ALD 2014 in Kyoto
“Tuomo Suntola’s Atomic Layer Epitaxy in Short” by Riikka Puurunen,
submitted (May 12, 2014) to Chem. Vap. Deposition
35. 35Puurunen, ALD 2014 Kyoto, June 15, 2014, tutorial session
Thank You!
Atomikerroskasvatus
השקעת אטומיות שכבות
εναπόθεση ατομικού στρώματος
Atomlagenabscheidung
Parmanu Parat Nishepan
परमाणु परत निक्षेपण
Deposizione a Strati Atomici
原子層堆積
원자층증착
आण्विक थर लेप
Atomlagsdeponering
атомно-слоевое осаждение
Dépôt de Couches Atomiques
Dépôt Chimique en Phase Vapeur à Flux Alternés
Atomlagerdeponering
Atomik Katman Biriktirme
Oсадження атомних шарів
Aatomkihtsadestus
Depositación de Capas Atómicas
Atomic Layer Deposition Atoomlaagdepositie
原子层沉积
Deposição por Camadas Atômicas
ALD name collection in LinkedIn ALD – Atomic Layer Deposition
Mолекулярное Hаслаивание