Puurunen, Aalto University CHEM-E5205, November 8, 2018
Introduction to atomic layer
deposition (ALD)
principles, applications, future
Prof. Riikka Puurunen
CHEM-E5205 Advanced Functional Materials 8.11.2018
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Lecture contents
1. Principles and concepts of ALD
2. Some history
3. Applications of ALD
4. Words on future
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Before we start, discussion:
• What do you already know of Atomic Layer Deposition (ALD)?
• Where can one find ALD films in practice?
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Connections between lectures
Where ALD?
?
?
? ?
?
yes
Puurunen, Aalto University CHEM-E5205, November 8, 2018
2018 Millennium Technology Prize
(MTP) to Dr. Tuomo Suntola for ALD
• MTP is Finland's tribute to
innovations for a better life.
• The Prize is worth one million
euros and it is awarded every
second year.
• Dr. Suntola thanks the
community for support and
shares honor for the prize.
Photo: Technology Academy Finland 2018
President Sauli Niinistö, Dr. Tuomo Suntola
More: www.taf.fi
http://aldhistory.blogspot.com/search/label/MTP2018
https://issuu.com/aaltouniversity/docs/aum_23_en_pdf-150dpi/24
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Expected learning outcomes
After this lecture, you should…
1. be able to describe the principles of ALD
2. be aware of the history of ALD including the two independent
discoveries
3. be able to name some applications where ALD is used
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD: Principles and concepts
Puurunen, Aalto University CHEM-E5205, November 8, 2018
The 2005 review by Puurunen
J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727
• Times cited: 1327 (as of 8.11.2018, WoS)
• Section III written to explain the surface chemistry concepts
• Section V written to discuss problematic assumptions
• Review used for teaching ALD
Puurunen, Aalto University CHEM-E5205, November 8, 2018
How is ALD defined?
” ALD can be defined as a film
deposition technique that is based
on the sequential use of self-
terminating gas–solid reactions”
Review: Puurunen JAP 97 (2005) 121301
ALD cycle
Reactant A
Reactant B
By-product
Substrate
before ALD
Step 2 /4
purge
Step 4 /4
purge
Step 1 /4
Reactant A
Step 3 /4
Reactant B
Reactant A
Reactant B
By-product
Puurunen, J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727
Open Access: https://www.vtt.fi/inf/julkaisut/muut/2010/Puurunen.pdf
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Self-terminating
 Saturating & irreversible
desorptionnon-saturation unsaturation
amount adsorbed saturates
amount adsorbed stays
NO:
pulse purge
Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
sequential use of self-terminating
gas–solid reactions
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Gas-solid reactions
 Chemical adsorption
Physisorption
• non-specific
• minimal electronic interaction
• chemical nature of the adsorbate
not altered
• adsorption energy similar to the
energy of condensation
(exothermic)
• non-activated
• equilibrium is established
• multilayers may form
Chemisorption
• chemical specificity
• changes in electronic state
• reversible/irreversible
• chemisorption energy as for a chemical
reaction (exothermic/endothermic)
• often involves an activation energy
• for “large” activation energies (“activated
adsorption”), true equilibrium may be
achieved slowly
• monolayer adsorption
http://old.iupac.org/reports/2001/colloid_2001/manual_of_s_and_t/node16.html
sequential use of self-terminating
gas–solid reactions
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Chemisorption
mechanisms
typical in ALD
Puurunen, J. Appl. Phys. 97 (2005) 121301.
https://doi.org/10.1063/1.1940727 open access pdf
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Growth per cycle (GPC)
• ALD is characterized by
a GPC, which depends
typically on:
• reactants
• temperature
• substrate
• In ALD, there is no
”growth rate” in the
sense as e.g. in
chemical vapor
deposition
Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
sequential use of self-terminating
gas–solid reactions
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Note: typically less than
monolayer growth per cycle
• ”Monolayer” has many definitions and can be confucing
Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
(a) a chemisorbed monolayer (the substrate before
chemisorption indicated above, with reactive sites
shown), (b) a physisorbed monolayer, and (c) a
monolayer of the ALD-grown material.
GPC rarely >50%
of a monolayer
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Concept of ”ALD window”
(original by Suntola)
Suntola 1981, re-shared in:
http://aldhistory.blogspot.com/2016/01/ald-terminology-discussion-ald-
window-2.html
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Concept of ”ALD window”
(original by Suntola)
Suntola, ”Atomic layer epitaxy” Mater. Sci. Rep. 4 (1989) 261-312.
DOI: 10.1016/S0920-2307(89)80006-4
Explanations (shortened by RLP)
L1: condensation to be prevented
L2: activation energy to exceed
H1: decomposition
H2: re-evaporation
How GPC can vary within an ALD window?
Puurunen, J. Appl. Phys. 97 (2005) 121301.
https://doi.org/10.1063/1.1940727 open access pdf
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Typical reactant/precursor classes
H2O
NH3
H2S
Non-metal precursors, “thermal” ALD
plasma-enhanced ALD (not for catalysts)
O2 N2
H2
Metal precursor type
Elements
Halides
Alkyls
Cyclopentadienyls
Alkoxides
b-diketonates
Alkylamides and
silylamides
Amidinates
InorganicMetal-organic
Organo-
metallic
Class
N
NM
N
M
O
M
O
O
M
M
M
M
Cl
M
etc
etc
Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Status of two-reactant ALD
process research >700 processes tested
Miikkulainen, Leskelä, Ritala, Puurunen (review), J. Appl. Phys. 113 (2013) 021301.
http://dx.doi.org/10.1063/1.4757907. open access pdf. >2000 references
Would be good
to update info
Puurunen, Aalto University CHEM-E5205, November 8, 2018
”Model ALD process”:
trimethylaluminium/water  Al2O3
Model status acknowledged/agreed e.g. in:
• Puurunen 2005, review on the TMA/water
process, DOI: 10.1063/1.1940727
• George 2010, DOI: 10.1021/cr900056b
• Miikkulainen et al. 2013, DOI:
10.1063/1.4757907
• Knapas & Ritala 2013, DOI:
10.1080/10408436.2012.693460
• Weckman & Laasonen 2018, DOI:
10.1039/C5CP01912E
• Van Bui et al. 2017, DOI:
10.1039/c6cc05568k
Van Bui, Grillo, Van Ommen, Chem. Commun. 53 (2017) 45. DOI: 10.1039/c6cc05568k
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Conformality: ALD’s core benefit
Sneh et al., Thin Solid
Films 402 (2002) 248.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Why use ALD?
ALD is not perfect!
• ALD overall slow (reactions
non-continuous)
• Special equipment and
chemicals needed  can be
expensive
• Sometimes, toxic chemicals
• ”Research grade” layers
often have impurities and
other non-idealities
ALD has many benefits
• Scalable to large substrates
& batch processing
• Reproducible, even from
equipment to equipment
( nature controlled)
• Excellent nucleation control
(first few monolayers of
growth)
• High (optimized) layer quality
• Unmatched conformality
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Where ALD?
Aalto University Magazine October 2018,
https://issuu.com/aaltouniversity/docs/aum_23_en_pdf-150dpi/24
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Some history
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Discovered independently twice
• Atomic layer epitaxy (ALE)
• 1974 
Molecular Layering (ML)
? 1965 
Dr. Tuomo S. Suntola
Photo:RiikkaPuurunen,Wikimedia
Prof. Valentin B. Aleskovskii
Prof. Stanislav I. Koltsov
Suntola T, Antson J (1974). Patent FIN 52359 (29 November 1974); corresponds to U.S.
patent 4 058 430 (25 November 1975).
Aleskovskii VB, Koltsov SI (1965). Some characteristics of molecular layering reactions.
In Abstract of Scientific and Technical Conference of the Leningrad Technological Institute
by Lensovet (Goskhimizdat, Leningrad, 1965), pp. 67–67 (in Russian).
Puurunen, J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727
Puurunen, Aalto University CHEM-E5205, November 8, 2018
• Launched in 2013 to make the
early days of ALD more
transparent
• Volunteer based
• Currently, >70 contributors
from >20 countries
• Voluntary coordinator:
Puurunen
• Colours: shades of gray
• In atmosphere of openness,
respect, and trust
http://vph-ald.com, http://aldhistory.blogspot.fi
Puurunen, Aalto University CHEM-E5205, November 8, 2018
VPHA started from a question
9.11.2018
26
May 6, 2013, Riikka Puurunen
LinkedIn ”ALD - Atomic Layer Deposition” group
https://www.linkedin.com/groups/1885076/1885076-238399494
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Atomic layer epitaxy (ALE)
Puurunen, Chem. Vap.
Deposition 20 (2014) 332-344.
DOI: 10.1002/cvde.201402012
• “A Short History of Atomic Layer
Deposition: Tuomo Suntola's
Atomic Layer Epitaxy”
• ALE-ALD in 1974, patent,
ZnS
FinALD40 exhibition – 40 years from filing the first patent in Nov 1974
ImagebyRiikkaPuurunen
VPHA article 1
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Learnings on the history of ALD,
atomic layer epitaxy (1/2)
• Spatial ALD concepts already
in the early ALE patents
• 1st conference presentation in
1980 with ALE-EL demo:
1000s of product inquiries
• 2nd conference presentation
by Suntola in 1981 laid seeds
for ALE development in Japan
9.11.2018
28
R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst
R. L. Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012
Sven Lindfors and the flow ALE-ALD
reactor in 1978
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Learnings on the history of ALD,
atomic layer epitaxy (2/2)
• ALE-EL airport display
demonstrator 15 years in
continuous use
• ALE-EL licensed to France to CGE
( Alcatel) in early 1980s
• Early ALD research in Finland was
fully related to EL displays
• ALD was used for CdTe
photovoltaic applications in 1990s
9.11.2018
29
R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst
R. L. Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012
Ralf Graeffe in 1983
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Molecular layering (ML)
9.11.2018
30
Malygin, Drozd, Malkov,
Smirnov, Chem. Vap.
Deposition 21 (2015) 216-240.
DOI: 10.1002/cvde.201502013
• From V. B. Aleskovskii's
“Framework” Hypothesis to the
Method of Molecular
Layering/Atomic Layer
Deposition
VPHA article 2
Aleskovskii, 1952, matrix hypothesis
Puurunen, Aalto University CHEM-E5205, November 8, 2018
PhotobyRiikkaPuurunen
Learnings on the history of ALD,
molecular layering side (1/2)
• Oldest confirmed written ML-ALD
record: abstract from 1965
• Atmospheric pressure used in
many early ML studies
• The first USSR patents on ALD
for catalysis date from 1972
• ML thin film growth in mid-1970s
• Early catalysis ALD works in
Bulgaria
9.11.2018
31
Drozd’s thin film reactor, 1977
Drozd
Baltic
ALD
2014
R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst
A. Malygin, V. E. Drozd, A. A. Malkov, V. M. Smirnov, Chem. Vap. Deposition 21 (2015) 216-240.
DOI: 10.1002/cvde.201502013
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Learnings on the history of ALD,
molecular layering side (2/2)
• Amine-catalysed SiO2 process
• In situ gravimetry during ML
• Small-scale production by ML-ALD
• Fluidized bed for particle coating
• Massive list of PhD theses
• Aleskovskii’s central academic role
• Central role of Koltsov’s ML thesis
9.11.2018
32
Malygin & particle ML-ALD reactor
1982
R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst
A. Malygin, V. E. Drozd, A. A. Malkov, V. M. Smirnov, Chem. Vap. Deposition 21 (2015) 216-240.
DOI: 10.1002/cvde.201502013
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Full slide set shared openly through ECSarXiv, DOI: 10.1149/osf.io/u6vw7
Related article, Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst, open access
preprint https://ecsarxiv.org/exyv3/
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Scientific articles on the
history of ALD
Puurunen, J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727
1. Puurunen, ”A Short History of Atomic Layer Deposition: Tuomo Suntola's Atomic Layer
Epitaxy,” Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012
2. Malygin, Drozd, Malkov, Smirnov, ”From V. B. Aleskovskii's “Framework” Hypothesis to
the Method of Molecular Layering/Atomic Layer Deposition,” Chem. Vap. Deposition 21
(2015) 216-240. DOI: 10.1002/cvde.201502013
3. Ahvenniemi et al. (62 coauthors), ”Review Article: Recommended reading list of early
publications on atomic layer deposition—Outcome of the “Virtual Project on the History
of ALD”,” J. Vac. Sci. Technol. A 31 (2017) 010801. DOI: 10.1116/1.4971389
4. 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: https://ecsarxiv.org/exyv3/)
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD theses
(VPHA)
• VPHA-generated
formally unpublished
summary of ALD
theses worldwide
• Image status: 07/2017
• Access and propose
to add info through:
http://vph-
ald.com/VPHAopenfile
s.html
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD timeline – RLP’s initial draft,
to be improved (in VPHA)
1965, 1st
record of
ML
1980s 1990s1970s1960s 2000s 2010s
1974, 1979,
Patents, ALE
1971,
Koltsov
thesis
1972
Catalysis
authors’s
inventions
ALE-EL display
factory
Fluidized
bed activity
1987
Microchemistry
Ltd, Finland
1st
catalysis
thesis,
Finland
DRAM
production
ALD high-k
in CMOS
Photovoltaics
2005 review
TMA-water
2013 VPHA
started
2018
Millennium
Technology Prize
Formally unpublished ALD timeline draft presented in Puurunen’s invited presentations
in 2018 at EMRS fall meeting Warsaw and ECS-AiMES symposium in Cancun Mexico
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD in industrial applications
Puurunen, Aalto University CHEM-E5205, November 8, 2018
”Strategic decisions to keep the
use of ALD as a trade secret …
concerns on patent issues ... ”
• Ritala, Niinistö, “Industrial Applications
of Atomic Layer Deposition”, ECS
Transactions 25 (2009) 641-652,
http://dx.doi.org/10.1149/1.3207651
” jos joku puolijohdevalmistaja
ottaisi tällaisen
passivointimenetelmän
käyttöönsä, ei se siitä kertoisi”
• https://lehti.tek.fi/bosund, accessed
31.10.2018
Photo by Riikka Puurunen / Taneli Ras
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD in numbers
• The yearly size of the ALD equipment market is estimated as
USD 1.4-1.5 Billion
• source: Gartner 2016 Wafer Equipment report, VLSI Research (CMC 2017)
and Sundqvist / BALD Engineering
• Forecast: ” Atomic Layer Deposition (ALD) Market Size
Worth $3.01 Billion By 2025”
• https://www.grandviewresearch.com/press-release/global-atomic-layer-deposition-market
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Companies selling ALD reactors
(RLP’s incomplete list from July 2018)
1. Aixtron (www.aixtron.com, USA),
2. ALD Nanosolutions (www.aldnanosolutions.com, USA),
3. Applied Materials (www.appliedmaterials.com, USA),
4. Arradiance (www.arradiance.com, USA),
5. ASM (www.asm.com, Netherlands),
6. Beneq (www.beneq.com, Finland),
7. CN1 (www.cn-1.co.kr/about-us/news, Korea),
8. Delft IMP (http://delft-imp.nl/, The Netherlands),
9. Encapsulix (www.encapsulix.com, France),
10. Eugene Technology (www.eugenetechnology.com, Korea),
11. Ferri Watt (www.magnetron.ru, Russia),
12. Holst Centre (www.holstcentre.com, The Netherlands),
13. Forge Nano (www.forgenano.com, USA),
14. Jusung Engineering (http://www.jseng.com/eng/, Korea),
15. Kobus (http://kobus-tech.com/, France)
16. Kurt J. Lesker (http://www.lesker.com/, USA),
17. LAM Research Corporation (www.lamresearch.com, USA),
18. Levitech (www.levitech.nl, The Netherlands),
19. Modularflow (www.modularflow.com, Germany),
20. Nano-Master (http://www.nanomaster.com/ald.html, USA),
21. NCD (http://www.ncdtech.co.kr/, Korea),
22. Oxford Instruments Plasma Technology (www.oxford-
instruments.com/plasma, UK),
23. Picosun (www.picosun.com, Finland),
24. Samco (www.samcointl.com, Japan),
25. Sentech (www.sentech.com, Germany),
26. SolayTech (http://www.solaytec.com/, The Netherlands),
27. Suga (http://www.suga.ne.jp/, Japan),
28. Sundew (http://www.sundewtech.com/, USA),
29. SVT Associates (www.svta.com, USA),
30. Tokyo Electron (www.tel.com, Japan),
31. Veeco CNT (www.veeco.com, http://www.cambridgenanotechald.com/, USA),
32. Wonik IPS (http://www.ips.co.kr/eng_main/sub1_1.php, Korea).
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Blog post: https://beneq.com/en/beneq/blog/playing-with-the-big-guys
Also: http://fortune.com/global500/
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Achievable functional properties,
for example
• Electrical: isolation, controlled leakage, conduction; high
dielectric constant
• Optical: transparency, high refractive index, low refractive
index, luminescence, …
• Chemical: resistance to given surrounding; controlled release;
hard mask in lithographic etching
• Morphological: controlled surface roughness
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Conformality as core benefit
Gutsche, Future Fab Intl. Issue 14; George, plenary talk, AVS-ALD 2013
Ni/zirconia, submitted, preprint DOI: 10.26434/chemrxiv.7204847.v1
Source: Applied Materials post
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Electroluminescent (EL) flat panel
displays 1985  (Espoo, Finland)
Ritala, Niinistö, ECS Transactions 25 (2009) 641-652. http://dx.doi.org/10.1149/1.3207651
Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012
Beneq blog 12.10.2018, accessed 31.10.2018 https://beneq.com/en/displays/blog/transparent-lumineq-matrix-
displays-just-got-lot-bigger
Luminescent:
ZnS:Mg
Insulating:
~200 nm
Al2O3, AlxTiyO
Puurunen, Aalto University CHEM-E5205, November 8, 2018
EL display in harsh environments
e.g. in Airbus A350
• Lumineq 5.7” TFEL display
• Service control display for water
management
Blog links:
• https://beneq.com/en/displays/applications/airbus-water-management-system
• https://beneq.com/displays/blog/lumineq-flying-high
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Newer: transparent TFEL displays
• Thanks to Beneq Oy for TASEL
the demo for teaching!
• https://beneq.com/en/displays/pr
oducts/tasel/elt-15s
• E.g., in 2019: Valtra tractors
• https://beneq.com/en/displays/bl
og/proven-in-field
• https://beneq.com/en/videos/lumi
neq-tour-in-agritechnica-valtra-
smartglass-windshield
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Thin film structure of TASEL
display
* A low atomic number capping layer has been used to protect the upper surface of the
sample during the ion beam thinning preparation of the section
Electron microscopy image courtesy of Beneq Oy
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Scheme courtesy of Beneq Oy
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Where ALD?
https://issuu.com/aaltouniversity/docs/aum_23_en_pdf-150dpi/24
Where is ALD in the smartphone?
• Memory chip, logics chip, sacrificial layer in lithography steps
• Where else?
• (One would need to know the technology used in smart phones to
be able to tell in detail)
• A bit related: ”Puhelin palasina” (in Finnish),
https://www.hs.fi/teknologia/art-2000005867359.html, accessed
31.10.2018
My solution  Ask Twitter!
Puurunen, Aalto University CHEM-E5205, November 8, 2018
”Twitter
knows first”
• https://twitter.com/rlpuu/status/1057620486136442880
Puurunen, Aalto University CHEM-E5205, November 8, 2018
CMOS transistors:
• ”High-k metal
gate technology”
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Multiple patterning
in lithography
” ALD for Self-Aligned
Multiple Patterning (SAxP)
– How litho has become
patterning and requires
ALD”, March 13, 2017, link
• In ”Atomic limits” blog by
Prof Kessels & coworkers,
TU Eindhoven
https://www.atomiclimits.com/2017/03/13/ald-for-self-aligned-
multiple-patterning-saxp-how-litho-has-become-patterning-and-
requires-ald/
http://www.blog.baldengineering.com/2014/04/video
-understanding-new-finfet.html
Puurunen, Aalto University CHEM-E5205, November 8, 2018
http://www.eenewsanalog.com//news/iedm-samsung-makes-3nm-gate-all-around-cmos
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD keep the Moore’s
law going
• IEEE Spectrum,
Oct 1, 2017
• https://spectrum.ie
ee.org/semiconduc
tors/design/the-
highk-solution
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Logic chips: 2007 
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Memory chips: 2004 
Sundqvist, Story of ZyALD, http://www.aldcoe.fi/events/finald40.pdf, accessed 31.10.2018
Shim et al., J. Mater. Chem. C, 2017, 5, 8000-
8013, DOI: 10.1039/C6TC05158H
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Microelectromechanical systems
(MEMS)
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Still from Twitter…
Answer to
https://twitter.com
/rlpuu/status/1057
620486136442880
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Protection against dark(ening)
forces, 2006 
M. Ritala, J. Niinistö, “Industrial Applications of Atomic Layer Deposition”, ECS
Transactions 25 (2009) 641-652, http://dx.doi.org/10.1149/1.3207651.
https://beneq.com/en/thin-films/blog/may-coating-be-you, accessed 31.10.2018
Barrier against
sulfur from air:
~10 nm Al2O3
protects Ag
(alloys) from
tarnishing
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD in the watchmaking industry
• Picosun press
release
• Probably reliable
• No application
details
http://www.watchpro.com/picosun-group-solidifies-position-watchmaking-market/
accessed 31.10.2018
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD in space
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Words on the future
• ”Playing the Wizard”…
• https://en.wikipedia.org/wiki/The_Wonderful_Wizard_of_Oz
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Microelectronics scaling continues
• Microelectronics will remain the driving force for ALD
development
• Counterpart developing rapidly, too:
atomic layer etching
• Kanarik et al., Journal of Vacuum Science &
Technology A 33, 020802
(2015); https://doi.org/10.1116/1.4913379
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Catalysis
• Third forthcoming, now worldwide
• Earlier: Soviet Union & Bulgaria; Finland
• Separate lecture, CHEM-E1130 Catalysis course
• Next course, MyCourses site:
https://mycourses.aalto.fi/course/view.php?id=20383
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Pharmaceuticals &
medical applications
• Controlled release of medicine
• Affecting the flow of powders
• Protective biocompatible layers
• Startups in Sweden, Finland/USA
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Saturation profile as
”the ALD observable”? name by Yanguas-Gil, 2017
Distance l (µm, mm, …)
Relative dimensionless distance l / g [r.d.u.]
Amount
grown
(nm,
# of atoms,
…)
(per cycle)
50%-thickness-
penetration-depth (PD50%)
Slope at PD50%
GPC just
inside + initial slope
Knee
GPC just
outside
x1. 2.
3.
4.
5. 6.
Gap entrance
(relative distance units)
Ylilammi, Ylivaara, Puurunen, J. Appl. Phys. 2018, DOI: 10.1063/1.5028178
Watch out for conformality review to be published, Cremers, Puurunen, Dendooven
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Debate on the surface chemistry
details of the ”model ALD process”?
• Slides by Puurunen at the Ireland ALD 2016 conference, oral presentation slides in SlideShare
• See also: Vandalon & Kessels 2017, DOI https://doi.org/10.1116/1.4993597; Winter 2018, DOI: 10.1149/osf.io/b6kzv
Puurunen, Aalto University CHEM-E5205, November 8, 2018
More / better citing of original
references?
• E.g., Suntola review from
1989 surprisingly little
cited
• DOI: 10.1016/S0920-
2307(89)80006-4
• Times cited: 426
(Elsevier statistics)
From: 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:
https://ecsarxiv.org/exyv3/ )
Puurunen, Aalto University CHEM-E5205, November 8, 2018
To conclude
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD: growing & transitioning field
• ALD: a multitool of nanotechnology
• ”The latest major breakthrough in the field of CVD”
Pedersen & Elliott 2014, DOI: 10.1007/s00214-014-1476-7
• 2018 Millennium Technology Prize
• https://finland.fi/business-innovation/finnish-physicist-tuomo-suntola-wins-
millennium-technology-prize/
• ALD invented independently twice
• 1st industrial application: flat panel displays 1980s ,
enabler of Moore’s law 2000s 
• Yearly ALD equipment market size >USD 1B
Puurunen, Aalto University CHEM-E5205, November 8, 2018
(Some) faces of ALD of Finland
Mr. Sven Lindfors
Dr. Tuomo Suntola
Prof. Markku Leskelä
University of Helsinki
Prof. Hele Savin
Aalto University
Prof. Maarit Karppinen
Aalto University
Prof. Riikka Puurunen
Aalto University
Prof. Mikko Ritala
University of Helsinki
+ Dr. Jonas
Sundqvist
BALD Engineering
+ Prof. Sean Barry
Carleton University
Companies: ASM, Beneq, Picosun, + 100’s of other faces
Photo: TAF Source: DOI: 10.1002/cvde.201402012
Photo:Puurunen,2014
Photo:Puurunen,2015
Photo:Puurunen,2014
Photo:HY,link
Photo:AaltoUniversity
Photo:AaltoUniversity
Photo:AaltoUniversity
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Additional information
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Aalto University
Magazine October
2018
https://issuu.com/aal
touniversity/docs/au
m_23_en_pdf-
150dpi/24
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Puurunen’s
latest
Publication
(submitted)
Puurunen, Riikka; Voigt, Pauline; Haimi, Eero;
Lahtinen, Jouko; Cheah, You Wayne; Mäkelä,
Eveliina; et al. (2018): Nickel Supported on
Mesoporous Zirconium Oxide by Atomic Layer
Deposition: Initial Fixed-Bed Reactor Study.
ChemRxiv. Preprint. Doi:
10.26434/chemrxiv.7204847.v1
Puurunen, Aalto University CHEM-E5205, November 8, 2018
STG podcasts – Aalto students, with ALD
Puurunen, Aalto University CHEM-E5205, November 8, 2018
More info on the VPHA
Virtual Project on the History of ALD
Puurunen, Aalto University CHEM-E5205, November 8, 2018
VPHA started from a question
9.11.2018
77
May 6, 2013, Riikka Puurunen
LinkedIn ”ALD - Atomic Layer Deposition” group
https://www.linkedin.com/groups/1885076/1885076-238399494
Puurunen, Aalto University CHEM-E5205, November 8, 2018
How does VPHA work?
*Voluntary *Open Science
• We collect together info on early ALD publications up to 1986
• We collect individual summaries (”comments”) on those
publications (goal: ≥3 comments/publication) in
the ALD-history-evolving-file, openly shared (Google Docs)
• Everyone who shares at least one comment, becomes
contributor (now: 76, from >20 countries in 4 continents)
 coauthor
• Website: http://vph-ald.com
• http://vph-ald.com/Publication%20Plan.html
• Blog: http://aldhistory.blogspot.fi
9.11.2018
78
Puurunen, Aalto University CHEM-E5205, November 8, 2018
9.11.2018
79
• Openness,
• Respect, and
• Trust
Colours: shades of gray
Puurunen, Aalto University CHEM-E5205, November 8, 2018
VPHA outcomes
• 4 scientific articles (reviews):
2 CVD, 1 JVSTA, 1 ECST
• Conference presentations:
~4 ALD, ~2 BALD
• Exhibition: 40 Years of ALD in
Finland – Photos, Stories
• Wikipedia updates
• Contributing to 2018 Millennium
Technolology Prize nomination
9.11.2018
80
2013
Malygin laboratory, 2013
https://twitter.com/rlpuu/status/509792544373620736
ALD 2014
2014
Puurunen, Aalto University CHEM-E5205, November 8, 2018
VPHA article 3
JVSTA 2017, DOI: 10.1116/1.4971389
Joint article, 62 co-authors
Review Article: Recommended reading list
of early publications on atomic layer
deposition—Outcome of the “Virtual
Project on the History of ALD”
• List of 22 significant publications
• Created by voting among VPHA
contributors
9.11.2018
81
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Ib
9.11.2018
82
DOI:
10.1149/08606.0003
ecst
ECSarXiv,
open acecss:
10.1149/osf.io/exyv3
ECST
#Aimes2018
VPHA article 4
Puurunen, Aalto University CHEM-E5205, November 8, 2018
VPHA continues,
final review to be written
• More contributors  co-authors welcome! Tentative contents:
• ALD history timeline – make by voting within VPHA?
• Cite each early ALD publication (confirm first they are ALD)
• List of doctoral theses on ALD, up to end of 2018
• List of ALD conferences, up to end of 2018?
• List of ALD reviews, up to end of 2018?
• Other contents?
• Interested? Contact Riikka Puurunen or: info @ vph-ald.com
9.11.2018
83
Puurunen, Aalto University CHEM-E5205, November 8, 2018
aalto.fi
Contact:
firstname.lastname@aalto.fi
Twitter: @rlpuu
Aalto: aalto.fi/cmet/catalysis Prof. Riikka Puurunen
Aalto University
Photo:AaltoUniversity

Introduction to atomic layer deposition (ALD): principles, applications, future

  • 1.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Introduction to atomic layer deposition (ALD) principles, applications, future Prof. Riikka Puurunen CHEM-E5205 Advanced Functional Materials 8.11.2018
  • 2.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Lecture contents 1. Principles and concepts of ALD 2. Some history 3. Applications of ALD 4. Words on future
  • 3.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Before we start, discussion: • What do you already know of Atomic Layer Deposition (ALD)? • Where can one find ALD films in practice?
  • 4.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Connections between lectures Where ALD? ? ? ? ? ? yes
  • 5.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 2018 Millennium Technology Prize (MTP) to Dr. Tuomo Suntola for ALD • MTP is Finland's tribute to innovations for a better life. • The Prize is worth one million euros and it is awarded every second year. • Dr. Suntola thanks the community for support and shares honor for the prize. Photo: Technology Academy Finland 2018 President Sauli Niinistö, Dr. Tuomo Suntola More: www.taf.fi http://aldhistory.blogspot.com/search/label/MTP2018 https://issuu.com/aaltouniversity/docs/aum_23_en_pdf-150dpi/24
  • 6.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Expected learning outcomes After this lecture, you should… 1. be able to describe the principles of ALD 2. be aware of the history of ALD including the two independent discoveries 3. be able to name some applications where ALD is used
  • 7.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD: Principles and concepts
  • 8.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 The 2005 review by Puurunen J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727 • Times cited: 1327 (as of 8.11.2018, WoS) • Section III written to explain the surface chemistry concepts • Section V written to discuss problematic assumptions • Review used for teaching ALD
  • 9.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 How is ALD defined? ” ALD can be defined as a film deposition technique that is based on the sequential use of self- terminating gas–solid reactions” Review: Puurunen JAP 97 (2005) 121301 ALD cycle Reactant A Reactant B By-product Substrate before ALD Step 2 /4 purge Step 4 /4 purge Step 1 /4 Reactant A Step 3 /4 Reactant B Reactant A Reactant B By-product Puurunen, J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727 Open Access: https://www.vtt.fi/inf/julkaisut/muut/2010/Puurunen.pdf
  • 10.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Self-terminating  Saturating & irreversible desorptionnon-saturation unsaturation amount adsorbed saturates amount adsorbed stays NO: pulse purge Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf sequential use of self-terminating gas–solid reactions
  • 11.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Gas-solid reactions  Chemical adsorption Physisorption • non-specific • minimal electronic interaction • chemical nature of the adsorbate not altered • adsorption energy similar to the energy of condensation (exothermic) • non-activated • equilibrium is established • multilayers may form Chemisorption • chemical specificity • changes in electronic state • reversible/irreversible • chemisorption energy as for a chemical reaction (exothermic/endothermic) • often involves an activation energy • for “large” activation energies (“activated adsorption”), true equilibrium may be achieved slowly • monolayer adsorption http://old.iupac.org/reports/2001/colloid_2001/manual_of_s_and_t/node16.html sequential use of self-terminating gas–solid reactions
  • 12.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Chemisorption mechanisms typical in ALD Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
  • 13.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Growth per cycle (GPC) • ALD is characterized by a GPC, which depends typically on: • reactants • temperature • substrate • In ALD, there is no ”growth rate” in the sense as e.g. in chemical vapor deposition Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf sequential use of self-terminating gas–solid reactions
  • 14.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Note: typically less than monolayer growth per cycle • ”Monolayer” has many definitions and can be confucing Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf (a) a chemisorbed monolayer (the substrate before chemisorption indicated above, with reactive sites shown), (b) a physisorbed monolayer, and (c) a monolayer of the ALD-grown material. GPC rarely >50% of a monolayer
  • 15.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Concept of ”ALD window” (original by Suntola) Suntola 1981, re-shared in: http://aldhistory.blogspot.com/2016/01/ald-terminology-discussion-ald- window-2.html
  • 16.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Concept of ”ALD window” (original by Suntola) Suntola, ”Atomic layer epitaxy” Mater. Sci. Rep. 4 (1989) 261-312. DOI: 10.1016/S0920-2307(89)80006-4 Explanations (shortened by RLP) L1: condensation to be prevented L2: activation energy to exceed H1: decomposition H2: re-evaporation How GPC can vary within an ALD window? Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
  • 17.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Typical reactant/precursor classes H2O NH3 H2S Non-metal precursors, “thermal” ALD plasma-enhanced ALD (not for catalysts) O2 N2 H2 Metal precursor type Elements Halides Alkyls Cyclopentadienyls Alkoxides b-diketonates Alkylamides and silylamides Amidinates InorganicMetal-organic Organo- metallic Class N NM N M O M O O M M M M Cl M etc etc Puurunen, J. Appl. Phys. 97 (2005) 121301. https://doi.org/10.1063/1.1940727 open access pdf
  • 18.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Status of two-reactant ALD process research >700 processes tested Miikkulainen, Leskelä, Ritala, Puurunen (review), J. Appl. Phys. 113 (2013) 021301. http://dx.doi.org/10.1063/1.4757907. open access pdf. >2000 references Would be good to update info
  • 19.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ”Model ALD process”: trimethylaluminium/water  Al2O3 Model status acknowledged/agreed e.g. in: • Puurunen 2005, review on the TMA/water process, DOI: 10.1063/1.1940727 • George 2010, DOI: 10.1021/cr900056b • Miikkulainen et al. 2013, DOI: 10.1063/1.4757907 • Knapas & Ritala 2013, DOI: 10.1080/10408436.2012.693460 • Weckman & Laasonen 2018, DOI: 10.1039/C5CP01912E • Van Bui et al. 2017, DOI: 10.1039/c6cc05568k Van Bui, Grillo, Van Ommen, Chem. Commun. 53 (2017) 45. DOI: 10.1039/c6cc05568k
  • 20.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Conformality: ALD’s core benefit Sneh et al., Thin Solid Films 402 (2002) 248.
  • 21.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Why use ALD? ALD is not perfect! • ALD overall slow (reactions non-continuous) • Special equipment and chemicals needed  can be expensive • Sometimes, toxic chemicals • ”Research grade” layers often have impurities and other non-idealities ALD has many benefits • Scalable to large substrates & batch processing • Reproducible, even from equipment to equipment ( nature controlled) • Excellent nucleation control (first few monolayers of growth) • High (optimized) layer quality • Unmatched conformality
  • 22.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Where ALD? Aalto University Magazine October 2018, https://issuu.com/aaltouniversity/docs/aum_23_en_pdf-150dpi/24
  • 23.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Some history
  • 24.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Discovered independently twice • Atomic layer epitaxy (ALE) • 1974  Molecular Layering (ML) ? 1965  Dr. Tuomo S. Suntola Photo:RiikkaPuurunen,Wikimedia Prof. Valentin B. Aleskovskii Prof. Stanislav I. Koltsov Suntola T, Antson J (1974). Patent FIN 52359 (29 November 1974); corresponds to U.S. patent 4 058 430 (25 November 1975). Aleskovskii VB, Koltsov SI (1965). Some characteristics of molecular layering reactions. In Abstract of Scientific and Technical Conference of the Leningrad Technological Institute by Lensovet (Goskhimizdat, Leningrad, 1965), pp. 67–67 (in Russian). Puurunen, J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727
  • 25.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 • Launched in 2013 to make the early days of ALD more transparent • Volunteer based • Currently, >70 contributors from >20 countries • Voluntary coordinator: Puurunen • Colours: shades of gray • In atmosphere of openness, respect, and trust http://vph-ald.com, http://aldhistory.blogspot.fi
  • 26.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 VPHA started from a question 9.11.2018 26 May 6, 2013, Riikka Puurunen LinkedIn ”ALD - Atomic Layer Deposition” group https://www.linkedin.com/groups/1885076/1885076-238399494
  • 27.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Atomic layer epitaxy (ALE) Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012 • “A Short History of Atomic Layer Deposition: Tuomo Suntola's Atomic Layer Epitaxy” • ALE-ALD in 1974, patent, ZnS FinALD40 exhibition – 40 years from filing the first patent in Nov 1974 ImagebyRiikkaPuurunen VPHA article 1
  • 28.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Learnings on the history of ALD, atomic layer epitaxy (1/2) • Spatial ALD concepts already in the early ALE patents • 1st conference presentation in 1980 with ALE-EL demo: 1000s of product inquiries • 2nd conference presentation by Suntola in 1981 laid seeds for ALE development in Japan 9.11.2018 28 R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst R. L. Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012 Sven Lindfors and the flow ALE-ALD reactor in 1978
  • 29.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Learnings on the history of ALD, atomic layer epitaxy (2/2) • ALE-EL airport display demonstrator 15 years in continuous use • ALE-EL licensed to France to CGE ( Alcatel) in early 1980s • Early ALD research in Finland was fully related to EL displays • ALD was used for CdTe photovoltaic applications in 1990s 9.11.2018 29 R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst R. L. Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012 Ralf Graeffe in 1983
  • 30.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Molecular layering (ML) 9.11.2018 30 Malygin, Drozd, Malkov, Smirnov, Chem. Vap. Deposition 21 (2015) 216-240. DOI: 10.1002/cvde.201502013 • From V. B. Aleskovskii's “Framework” Hypothesis to the Method of Molecular Layering/Atomic Layer Deposition VPHA article 2 Aleskovskii, 1952, matrix hypothesis
  • 31.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 PhotobyRiikkaPuurunen Learnings on the history of ALD, molecular layering side (1/2) • Oldest confirmed written ML-ALD record: abstract from 1965 • Atmospheric pressure used in many early ML studies • The first USSR patents on ALD for catalysis date from 1972 • ML thin film growth in mid-1970s • Early catalysis ALD works in Bulgaria 9.11.2018 31 Drozd’s thin film reactor, 1977 Drozd Baltic ALD 2014 R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst A. Malygin, V. E. Drozd, A. A. Malkov, V. M. Smirnov, Chem. Vap. Deposition 21 (2015) 216-240. DOI: 10.1002/cvde.201502013
  • 32.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Learnings on the history of ALD, molecular layering side (2/2) • Amine-catalysed SiO2 process • In situ gravimetry during ML • Small-scale production by ML-ALD • Fluidized bed for particle coating • Massive list of PhD theses • Aleskovskii’s central academic role • Central role of Koltsov’s ML thesis 9.11.2018 32 Malygin & particle ML-ALD reactor 1982 R. L. Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst A. Malygin, V. E. Drozd, A. A. Malkov, V. M. Smirnov, Chem. Vap. Deposition 21 (2015) 216-240. DOI: 10.1002/cvde.201502013
  • 33.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Full slide set shared openly through ECSarXiv, DOI: 10.1149/osf.io/u6vw7 Related article, Puurunen, ECS Transactions 86 (6) (2018) 3-17. DOI: 10.1149/08606.0003ecst, open access preprint https://ecsarxiv.org/exyv3/
  • 34.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Scientific articles on the history of ALD Puurunen, J. Appl. Phys. 97 (2005) 121301. DOI: 10.1063/1.1940727 1. Puurunen, ”A Short History of Atomic Layer Deposition: Tuomo Suntola's Atomic Layer Epitaxy,” Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012 2. Malygin, Drozd, Malkov, Smirnov, ”From V. B. Aleskovskii's “Framework” Hypothesis to the Method of Molecular Layering/Atomic Layer Deposition,” Chem. Vap. Deposition 21 (2015) 216-240. DOI: 10.1002/cvde.201502013 3. Ahvenniemi et al. (62 coauthors), ”Review Article: Recommended reading list of early publications on atomic layer deposition—Outcome of the “Virtual Project on the History of ALD”,” J. Vac. Sci. Technol. A 31 (2017) 010801. DOI: 10.1116/1.4971389 4. 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: https://ecsarxiv.org/exyv3/)
  • 35.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD theses (VPHA) • VPHA-generated formally unpublished summary of ALD theses worldwide • Image status: 07/2017 • Access and propose to add info through: http://vph- ald.com/VPHAopenfile s.html
  • 36.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD timeline – RLP’s initial draft, to be improved (in VPHA) 1965, 1st record of ML 1980s 1990s1970s1960s 2000s 2010s 1974, 1979, Patents, ALE 1971, Koltsov thesis 1972 Catalysis authors’s inventions ALE-EL display factory Fluidized bed activity 1987 Microchemistry Ltd, Finland 1st catalysis thesis, Finland DRAM production ALD high-k in CMOS Photovoltaics 2005 review TMA-water 2013 VPHA started 2018 Millennium Technology Prize Formally unpublished ALD timeline draft presented in Puurunen’s invited presentations in 2018 at EMRS fall meeting Warsaw and ECS-AiMES symposium in Cancun Mexico
  • 37.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD in industrial applications
  • 38.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ”Strategic decisions to keep the use of ALD as a trade secret … concerns on patent issues ... ” • Ritala, Niinistö, “Industrial Applications of Atomic Layer Deposition”, ECS Transactions 25 (2009) 641-652, http://dx.doi.org/10.1149/1.3207651 ” jos joku puolijohdevalmistaja ottaisi tällaisen passivointimenetelmän käyttöönsä, ei se siitä kertoisi” • https://lehti.tek.fi/bosund, accessed 31.10.2018 Photo by Riikka Puurunen / Taneli Ras
  • 39.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD in numbers • The yearly size of the ALD equipment market is estimated as USD 1.4-1.5 Billion • source: Gartner 2016 Wafer Equipment report, VLSI Research (CMC 2017) and Sundqvist / BALD Engineering • Forecast: ” Atomic Layer Deposition (ALD) Market Size Worth $3.01 Billion By 2025” • https://www.grandviewresearch.com/press-release/global-atomic-layer-deposition-market
  • 40.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Companies selling ALD reactors (RLP’s incomplete list from July 2018) 1. Aixtron (www.aixtron.com, USA), 2. ALD Nanosolutions (www.aldnanosolutions.com, USA), 3. Applied Materials (www.appliedmaterials.com, USA), 4. Arradiance (www.arradiance.com, USA), 5. ASM (www.asm.com, Netherlands), 6. Beneq (www.beneq.com, Finland), 7. CN1 (www.cn-1.co.kr/about-us/news, Korea), 8. Delft IMP (http://delft-imp.nl/, The Netherlands), 9. Encapsulix (www.encapsulix.com, France), 10. Eugene Technology (www.eugenetechnology.com, Korea), 11. Ferri Watt (www.magnetron.ru, Russia), 12. Holst Centre (www.holstcentre.com, The Netherlands), 13. Forge Nano (www.forgenano.com, USA), 14. Jusung Engineering (http://www.jseng.com/eng/, Korea), 15. Kobus (http://kobus-tech.com/, France) 16. Kurt J. Lesker (http://www.lesker.com/, USA), 17. LAM Research Corporation (www.lamresearch.com, USA), 18. Levitech (www.levitech.nl, The Netherlands), 19. Modularflow (www.modularflow.com, Germany), 20. Nano-Master (http://www.nanomaster.com/ald.html, USA), 21. NCD (http://www.ncdtech.co.kr/, Korea), 22. Oxford Instruments Plasma Technology (www.oxford- instruments.com/plasma, UK), 23. Picosun (www.picosun.com, Finland), 24. Samco (www.samcointl.com, Japan), 25. Sentech (www.sentech.com, Germany), 26. SolayTech (http://www.solaytec.com/, The Netherlands), 27. Suga (http://www.suga.ne.jp/, Japan), 28. Sundew (http://www.sundewtech.com/, USA), 29. SVT Associates (www.svta.com, USA), 30. Tokyo Electron (www.tel.com, Japan), 31. Veeco CNT (www.veeco.com, http://www.cambridgenanotechald.com/, USA), 32. Wonik IPS (http://www.ips.co.kr/eng_main/sub1_1.php, Korea).
  • 41.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Blog post: https://beneq.com/en/beneq/blog/playing-with-the-big-guys Also: http://fortune.com/global500/
  • 42.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Achievable functional properties, for example • Electrical: isolation, controlled leakage, conduction; high dielectric constant • Optical: transparency, high refractive index, low refractive index, luminescence, … • Chemical: resistance to given surrounding; controlled release; hard mask in lithographic etching • Morphological: controlled surface roughness
  • 43.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Conformality as core benefit Gutsche, Future Fab Intl. Issue 14; George, plenary talk, AVS-ALD 2013 Ni/zirconia, submitted, preprint DOI: 10.26434/chemrxiv.7204847.v1 Source: Applied Materials post
  • 44.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Electroluminescent (EL) flat panel displays 1985  (Espoo, Finland) Ritala, Niinistö, ECS Transactions 25 (2009) 641-652. http://dx.doi.org/10.1149/1.3207651 Puurunen, Chem. Vap. Deposition 20 (2014) 332-344. DOI: 10.1002/cvde.201402012 Beneq blog 12.10.2018, accessed 31.10.2018 https://beneq.com/en/displays/blog/transparent-lumineq-matrix- displays-just-got-lot-bigger Luminescent: ZnS:Mg Insulating: ~200 nm Al2O3, AlxTiyO
  • 45.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 EL display in harsh environments e.g. in Airbus A350 • Lumineq 5.7” TFEL display • Service control display for water management Blog links: • https://beneq.com/en/displays/applications/airbus-water-management-system • https://beneq.com/displays/blog/lumineq-flying-high
  • 46.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Newer: transparent TFEL displays • Thanks to Beneq Oy for TASEL the demo for teaching! • https://beneq.com/en/displays/pr oducts/tasel/elt-15s • E.g., in 2019: Valtra tractors • https://beneq.com/en/displays/bl og/proven-in-field • https://beneq.com/en/videos/lumi neq-tour-in-agritechnica-valtra- smartglass-windshield
  • 47.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Thin film structure of TASEL display * A low atomic number capping layer has been used to protect the upper surface of the sample during the ion beam thinning preparation of the section Electron microscopy image courtesy of Beneq Oy
  • 48.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Scheme courtesy of Beneq Oy
  • 49.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Where ALD? https://issuu.com/aaltouniversity/docs/aum_23_en_pdf-150dpi/24 Where is ALD in the smartphone? • Memory chip, logics chip, sacrificial layer in lithography steps • Where else? • (One would need to know the technology used in smart phones to be able to tell in detail) • A bit related: ”Puhelin palasina” (in Finnish), https://www.hs.fi/teknologia/art-2000005867359.html, accessed 31.10.2018 My solution  Ask Twitter!
  • 50.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ”Twitter knows first” • https://twitter.com/rlpuu/status/1057620486136442880
  • 51.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 CMOS transistors: • ”High-k metal gate technology”
  • 52.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Multiple patterning in lithography ” ALD for Self-Aligned Multiple Patterning (SAxP) – How litho has become patterning and requires ALD”, March 13, 2017, link • In ”Atomic limits” blog by Prof Kessels & coworkers, TU Eindhoven https://www.atomiclimits.com/2017/03/13/ald-for-self-aligned- multiple-patterning-saxp-how-litho-has-become-patterning-and- requires-ald/ http://www.blog.baldengineering.com/2014/04/video -understanding-new-finfet.html
  • 53.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 http://www.eenewsanalog.com//news/iedm-samsung-makes-3nm-gate-all-around-cmos
  • 54.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD keep the Moore’s law going • IEEE Spectrum, Oct 1, 2017 • https://spectrum.ie ee.org/semiconduc tors/design/the- highk-solution
  • 55.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Logic chips: 2007 
  • 56.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Memory chips: 2004  Sundqvist, Story of ZyALD, http://www.aldcoe.fi/events/finald40.pdf, accessed 31.10.2018 Shim et al., J. Mater. Chem. C, 2017, 5, 8000- 8013, DOI: 10.1039/C6TC05158H
  • 57.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Microelectromechanical systems (MEMS)
  • 58.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Still from Twitter… Answer to https://twitter.com /rlpuu/status/1057 620486136442880
  • 59.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Protection against dark(ening) forces, 2006  M. Ritala, J. Niinistö, “Industrial Applications of Atomic Layer Deposition”, ECS Transactions 25 (2009) 641-652, http://dx.doi.org/10.1149/1.3207651. https://beneq.com/en/thin-films/blog/may-coating-be-you, accessed 31.10.2018 Barrier against sulfur from air: ~10 nm Al2O3 protects Ag (alloys) from tarnishing
  • 60.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD in the watchmaking industry • Picosun press release • Probably reliable • No application details http://www.watchpro.com/picosun-group-solidifies-position-watchmaking-market/ accessed 31.10.2018
  • 61.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD in space
  • 62.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Words on the future • ”Playing the Wizard”… • https://en.wikipedia.org/wiki/The_Wonderful_Wizard_of_Oz
  • 63.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Microelectronics scaling continues • Microelectronics will remain the driving force for ALD development • Counterpart developing rapidly, too: atomic layer etching • Kanarik et al., Journal of Vacuum Science & Technology A 33, 020802 (2015); https://doi.org/10.1116/1.4913379
  • 64.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Catalysis • Third forthcoming, now worldwide • Earlier: Soviet Union & Bulgaria; Finland • Separate lecture, CHEM-E1130 Catalysis course • Next course, MyCourses site: https://mycourses.aalto.fi/course/view.php?id=20383
  • 65.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Pharmaceuticals & medical applications • Controlled release of medicine • Affecting the flow of powders • Protective biocompatible layers • Startups in Sweden, Finland/USA
  • 66.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Saturation profile as ”the ALD observable”? name by Yanguas-Gil, 2017 Distance l (µm, mm, …) Relative dimensionless distance l / g [r.d.u.] Amount grown (nm, # of atoms, …) (per cycle) 50%-thickness- penetration-depth (PD50%) Slope at PD50% GPC just inside + initial slope Knee GPC just outside x1. 2. 3. 4. 5. 6. Gap entrance (relative distance units) Ylilammi, Ylivaara, Puurunen, J. Appl. Phys. 2018, DOI: 10.1063/1.5028178 Watch out for conformality review to be published, Cremers, Puurunen, Dendooven
  • 67.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Debate on the surface chemistry details of the ”model ALD process”? • Slides by Puurunen at the Ireland ALD 2016 conference, oral presentation slides in SlideShare • See also: Vandalon & Kessels 2017, DOI https://doi.org/10.1116/1.4993597; Winter 2018, DOI: 10.1149/osf.io/b6kzv
  • 68.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 More / better citing of original references? • E.g., Suntola review from 1989 surprisingly little cited • DOI: 10.1016/S0920- 2307(89)80006-4 • Times cited: 426 (Elsevier statistics) From: 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: https://ecsarxiv.org/exyv3/ )
  • 69.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 To conclude
  • 70.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 ALD: growing & transitioning field • ALD: a multitool of nanotechnology • ”The latest major breakthrough in the field of CVD” Pedersen & Elliott 2014, DOI: 10.1007/s00214-014-1476-7 • 2018 Millennium Technology Prize • https://finland.fi/business-innovation/finnish-physicist-tuomo-suntola-wins- millennium-technology-prize/ • ALD invented independently twice • 1st industrial application: flat panel displays 1980s , enabler of Moore’s law 2000s  • Yearly ALD equipment market size >USD 1B
  • 71.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 (Some) faces of ALD of Finland Mr. Sven Lindfors Dr. Tuomo Suntola Prof. Markku Leskelä University of Helsinki Prof. Hele Savin Aalto University Prof. Maarit Karppinen Aalto University Prof. Riikka Puurunen Aalto University Prof. Mikko Ritala University of Helsinki + Dr. Jonas Sundqvist BALD Engineering + Prof. Sean Barry Carleton University Companies: ASM, Beneq, Picosun, + 100’s of other faces Photo: TAF Source: DOI: 10.1002/cvde.201402012 Photo:Puurunen,2014 Photo:Puurunen,2015 Photo:Puurunen,2014 Photo:HY,link Photo:AaltoUniversity Photo:AaltoUniversity Photo:AaltoUniversity
  • 72.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Additional information
  • 73.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Aalto University Magazine October 2018 https://issuu.com/aal touniversity/docs/au m_23_en_pdf- 150dpi/24
  • 74.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Puurunen’s latest Publication (submitted) Puurunen, Riikka; Voigt, Pauline; Haimi, Eero; Lahtinen, Jouko; Cheah, You Wayne; Mäkelä, Eveliina; et al. (2018): Nickel Supported on Mesoporous Zirconium Oxide by Atomic Layer Deposition: Initial Fixed-Bed Reactor Study. ChemRxiv. Preprint. Doi: 10.26434/chemrxiv.7204847.v1
  • 75.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 STG podcasts – Aalto students, with ALD
  • 76.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 More info on the VPHA Virtual Project on the History of ALD
  • 77.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 VPHA started from a question 9.11.2018 77 May 6, 2013, Riikka Puurunen LinkedIn ”ALD - Atomic Layer Deposition” group https://www.linkedin.com/groups/1885076/1885076-238399494
  • 78.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 How does VPHA work? *Voluntary *Open Science • We collect together info on early ALD publications up to 1986 • We collect individual summaries (”comments”) on those publications (goal: ≥3 comments/publication) in the ALD-history-evolving-file, openly shared (Google Docs) • Everyone who shares at least one comment, becomes contributor (now: 76, from >20 countries in 4 continents)  coauthor • Website: http://vph-ald.com • http://vph-ald.com/Publication%20Plan.html • Blog: http://aldhistory.blogspot.fi 9.11.2018 78
  • 79.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 9.11.2018 79 • Openness, • Respect, and • Trust Colours: shades of gray
  • 80.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 VPHA outcomes • 4 scientific articles (reviews): 2 CVD, 1 JVSTA, 1 ECST • Conference presentations: ~4 ALD, ~2 BALD • Exhibition: 40 Years of ALD in Finland – Photos, Stories • Wikipedia updates • Contributing to 2018 Millennium Technolology Prize nomination 9.11.2018 80 2013 Malygin laboratory, 2013 https://twitter.com/rlpuu/status/509792544373620736 ALD 2014 2014
  • 81.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 VPHA article 3 JVSTA 2017, DOI: 10.1116/1.4971389 Joint article, 62 co-authors Review Article: Recommended reading list of early publications on atomic layer deposition—Outcome of the “Virtual Project on the History of ALD” • List of 22 significant publications • Created by voting among VPHA contributors 9.11.2018 81
  • 82.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 Ib 9.11.2018 82 DOI: 10.1149/08606.0003 ecst ECSarXiv, open acecss: 10.1149/osf.io/exyv3 ECST #Aimes2018 VPHA article 4
  • 83.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 VPHA continues, final review to be written • More contributors  co-authors welcome! Tentative contents: • ALD history timeline – make by voting within VPHA? • Cite each early ALD publication (confirm first they are ALD) • List of doctoral theses on ALD, up to end of 2018 • List of ALD conferences, up to end of 2018? • List of ALD reviews, up to end of 2018? • Other contents? • Interested? Contact Riikka Puurunen or: info @ vph-ald.com 9.11.2018 83
  • 84.
    Puurunen, Aalto UniversityCHEM-E5205, November 8, 2018 aalto.fi Contact: firstname.lastname@aalto.fi Twitter: @rlpuu Aalto: aalto.fi/cmet/catalysis Prof. Riikka Puurunen Aalto University Photo:AaltoUniversity