1.
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

2.
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

3.
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?

4.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Connections between lectures
Where ALD?
?
?
? ?
?
yes

5.
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

6.
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

7.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD: Principles and concepts

8.
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

9.
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

10.
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

11.
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

12.
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

13.
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

14.
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

15.
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

16.
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

17.
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

18.
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

19.
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

20.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Conformality: ALD’s core benefit
Sneh et al., Thin Solid
Films 402 (2002) 248.

21.
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

22.
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

23.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Some history

24.
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

25.
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

26.
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

27.
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

28.
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

29.
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

30.
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

31.
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

32.
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

33.
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/

34.
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/)

35.
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

36.
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

37.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD in industrial applications

38.
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

39.
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

40.
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).

41.
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/

42.
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

43.
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

44.
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

45.
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

46.
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

47.
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

48.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Scheme courtesy of Beneq Oy

49.
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!

50.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
”Twitter
knows first”
• https://twitter.com/rlpuu/status/1057620486136442880

51.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
CMOS transistors:
• ”High-k metal
gate technology”

52.
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

53.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
http://www.eenewsanalog.com//news/iedm-samsung-makes-3nm-gate-all-around-cmos

54.
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

55.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Logic chips: 2007 

56.
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

57.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Microelectromechanical systems
(MEMS)

58.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Still from Twitter…
Answer to
https://twitter.com
/rlpuu/status/1057
620486136442880

59.
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

60.
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

61.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
ALD in space

62.
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

63.
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

64.
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

65.
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

66.
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

67.
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

68.
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/ )

69.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
To conclude

70.
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

71.
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

72.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
Additional information

73.
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

74.
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

75.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
STG podcasts – Aalto students, with ALD

76.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
More info on the VPHA
Virtual Project on the History of ALD

77.
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

78.
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

79.
Puurunen, Aalto University CHEM-E5205, November 8, 2018
9.11.2018
79
• Openness,
• Respect, and
• Trust
Colours: shades of gray

80.
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

81.
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

82.
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

83.
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

84.
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