Layer Deposition CVD ALD CVD and Nanomaterials applications Nigel Matthews Agenda Who we are Brief overview ALD materials amp applications A CVD application and comparison with ALD ID: 816671
Download The PPT/PDF document "Precursors used in Atomic" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Precursors used in
Atomic Layer Deposition /CVD ALD, CVD and Nanomaterials applications
Nigel Matthews
Slide2Agenda
Who we areBrief overview ALD, materials & applicationsA CVD application and comparison with ALD
A few Nanomaterials & applications
Slide3Product &Markets Served
Key Product Lines
Metal Catalysts
Ligands
CVD/ALD Precursors
Nanomaterials
Pharmaceutical
Chemical/Petrochemical
Micro
Electronics
Many
Academic /
Industrial
Research
Centers
Slide4Strem Product Line History:
1965 – Metal carbonyls, initially for chemical synthesis1984 – Electronic chemicals (MOCVD)
2004- Nanomaterials2012- Metal Organic Frameworks (MOFs)
Slide5ALD precursors come in many forms
Mainly a combination of metallic and organic elements
Metal alkyls
Metal alkylamides
Volatile metal carbonyls
Metal alkoxides
Metal betadiketonates (and ligands)
Volatile organometallics
Slide6Metal Alkyls
Slide7Alkyl Amides
Slide8Volatile
Metal Carbonyls
Slide9Metal Alkoxides
Slide10Metal Beta-Diketonates
Slide11Volatile Organometallics
Slide12Metal Halides
Cl
Cl
Cl
Cl
Ti
Slide13ALD Materials by Type
From Introduction to the Chemistry of ALD, 2011 Prof. Roy Gordon
Slide14ALD Reaction Sequence
14
Adapted from
CambridgeNanotech (
now part of Ultratech)
Slide15time
TMA = (
CH3)3Al Precursor A
H2O Precursor B
Pump
away Purge
Pump
away Purge
Example – Al2O3 Deposition Cycle
Single Cycle
Slide16Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
In air H
2
O vapour is absorbed on most surfaces, forming a hydroxyle group
With Silicon this forms Si-O-H
After placing the substrate in the reactor Trimethyl Alumina (TMA) is pulsed into reaction chamber.
Slide17Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
Slide18Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
Slide19Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
Slide20Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
Slide21Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
Slide22Example – Al2O3 Deposition Cycle
Adapted from CambridgeNanotech
Slide23ALD cycle of Al
2O3 plasma enhanced
Slide24ALD system Components
rapidplasmastrikingfast ALD
valves
turbo
pump
APC
Remote plasma
High radical density at low ion bombardment
Fast saturation
Fast pressure control
Efficient use of precursor and fast saturation
Quick removal of reaction products
Slide25Dip tube
Liquid or solid precursors e
xample: MoCl
5
,
Mo(CO)
6
, W(CO)
6
, DTBSe etc
Can be heated increase vapour pressure.
Vapour draw, carrier gas assist or bubbling modes
Precursor Delivery Options, Bubblers
Vapour draw
(high vapour pressure liquids)
Bubbling
(low vapour pressure liquids)
Carrier gas assist
(solids)
Slide26ALD Reaction Temperatures
Adapted from CambridgeNanotech
(now part of Ultratech)
Slide27Benefits of ALD
Adapted from
CambridgeNanotech (
now part of Ultratech)
Perfect films
Digital control of film thickness
Excellent repeatability
100% film density
Amorphous or crystalline films
Conformal Coating
Excellent 3D conformity
Ultra high aspect ratio (> 2,000:1)
Large area thickness uniformity
Atomically flat and smooth coating
Challenging Substrates
Gentle deposition process for sensitive substrates
Low temperature and low stressExcellent adhesion
Coats challenging substrates – even teflon
Slide28ALD Applications
Adapted from CambridgeNanotech
(now part of Ultratech)
Slide29Al
2O3 as a dielectric for high-density trench capacitors
Data courtesy of Eindhoven University of Technology & Philips Research.
Dielectric constant: 8.5
Breakdown: 9.5 MV/cm
Slide30Tyndall Super Capacitor
Slide31Tyndall Super Capacitor
Slide322D transition metal dichalcogenides(e.g. MoS
2 and WSe2(Tungsten diselenide)) promising for future transistors.FlexAL ALD Al2O3 on both sides was used to make WSe2 field effect transistors with high mobility.Al2O3 as high-k dielectric for 2D transistors
Liu et al.,
Nano Lett.
13
, 1983 (2013)
Mobility improvement with Al
2
O
3
on top
(deposited on 1 nm PVD Ti seed layer at 120 °C)
Exfoliated monolayer WSe
2
http://nrl.ece.ucsb.edu/
Slide33Remote plasma ALD: Al
2O3 barrier deposition at room temperature Excellent single layer barrier (20-40 nm Al2O3) Water Vapour Transmission Rate Test (WVTR) = ≤ 2·10-6 g·m
-2·day-1Development towards flexible electronics such as OLEDs
Moisture barrier results
Keuning et al.,
J. Vac. Sci. Technol. A
30
, 01A131 (2012)
Slide34Hoex et al.,
Appl.Phys.Lett. 89, 042112 (2006)Dingemans et al., Phys.Status Solidi RRL 4, 10 (2010)Van Delft et al., Semicon.Sci.Technol. 27, 074002 (2012)
Richter et al., Phys. Rev
. B
86
, 165202 (2012)
Solar cells: c-Si passivation
ALD layers for passivation at the interface with c-Si.
Plasma ALD of Al
2
O
3
recognized as best surface passivation
FlexALs and OpALs
used in fundamental studies to cancel surface recombination.ALD SiO2/Al2O3 stacks for passivation of n-doped surfaces.
Slide35Si nanograting to filter out EUV.Coating with ALD Pt and Al
2O3.Best EUV blocking using 20 nm Pt layer.Nanogratings for solar wind sensorsKaplan et al., ACS Photonics 1, 554 (2014)
Conformal coating of 20 nm Pt in 75 nm by 2.5 m
m trench
(AR 33 to 71 after coating)
Pt on FlexAL
Al
2
O
3
on OpAL
Slide36Slide37Slide38Slide39Slide40Slide41Chemical Vapour Deposition
Slide42MoS2 grown on sapphire
CVD processNo pre-treatment requiredGrowth on dielectrics does not require catalystOther precursors, e.g. metal organics can be usedEDS shows low chlorine impuritiesCVD MoS2 Process Details Substrate
Sapphire, Alumina, SiO2
Temperature
600-900 ºC
Precursors
H
2
S, MoCl
5
(in FVD bubbled with
Ar
flow),
H
2
MoS2 film on SapphireScratch
EDS: Presence of Mo, S and very low/no ClProcess flow diagram
Slide43Preferential growth of ZnO film by ALD
XRD patterns for
ZnO
film prepared by
ALD, at different temperature.
Precursors:
DEZn
+ H
2
O
SEM for ZnO film deposited
by ALD at
145
o
C
ZnO layer (CVD) (polycrystals)
ZnO layer (ALD) (polycrystals)
Si substrate
ZnO NWs (CVD) (single crystal)
Nanotechnology 19 (2008) 435609
Slide44Preferential Growth of
ZnO
NWs by CVD
On ALD deposited
ZnO
seed layer
silicon
silicon
silicon
c-axis direction for (00.2)
c-axis direction for (10.0)
155
o
C
175
o
C
280
o
C
ZnO NW
SEM for CVD grown
ZnO
nanowire
silicon
silicon
silicon
ALD film
(seed layer)
CVD grown
nanowire
Nanotechnology 19 (2008) 435609
Slide45Comparison of ALD and CVD
Slide46Nanomaterials
Slide47Gold nanoparticles. Cancer treatment
According to the World Health Organisation (WHO), 7.6 million people died from cancer in 2008, despite advances in diagnosis and treatment. Nanotechnology research is developing more efficient and accurate methods of delivering drugs and other cancer treatments.The drug is bound to gold particles, which are injected into the bloodstream and travel to the site of the tumour, treating it while leaving surrounding tissue largely unaffected. The technology has gone through its Phase I clinical trials and is undergoing further testing in collaboration with the pharmaceutical company AstraZeneca.
Use of “nanoshells”, consisting of a gold-coated core of silica, which heat up when a laser light of a specific frequency is directed at them. These particles are injected into the tumour, which is then illuminated with a near-infrared laser, destroying the cancer cells with heat.
Web Site: Source World gold Council
Slide48Gold nanoparticles. Cancer Identification
Web Site: Source World gold Council
Slide49Graphene/ Graphene oxide
Some claims for Graphene:
Increase
thermal conductivity and stability
Increase
electrical conductivity
Improve
barrier properties
Reduce
component mass while maintaining or improving properties
Increase
stiffness
Increase
toughness (impact strength)
Improve
appearance, including scratch and mar resistance
Increase flame retardance
Slide50Graphene/ Graphene oxide
Application RequestsEnergy StorageImproved strength concrete, stopping crack propagation.Modifying properties of polymeric coatings, oxide might have better bonding due to presence of OH, COOH and COCH3 groups.
Gaskets, improving thermal and electrical properties.
Request for Transparent Conductors / Inks
Slide51Large-pore Iron(III) carboxylate
Porous metal-organic frameworks (MOFs) have interesting coordination structures and topologies, with notable features including well-defined crystalline structures, regular pore structures, and very high porosities and surface areas.Consequently, these advanced functional materials have potential use in gas/liquid storage, gas separation, adsorption chiller, dehumidification, catalysis, drug delivery, magnetic and optical devices, and many other applications.
Slide52Quantum
Dots :Emitter in Back Light Unit (BLU)
Alreaday established technology (Sony (2013), TCL (2014), Samsung (2015), a.o.Based
on
conventional
flatscreen-technology
, BLU can
be
integrated
easily
by manufactorPrinciple:
LEDs in BLU create blue light (450 nm)light radiates through layer with green (530 nm) and red (620 nm) emitting
QDs combination of blue LED light and particles emitting at 530 and 620 nm lead to white lightPixel circuit via established LCD-technologyRequirement to NP: high efficiency, stable
over several years52
Slide53Acknowledgements
CAN GmbH- Katharina PoulsenNottingham Uni - Fang XuOxford Instruments – Ravi Sundaram Harm KnoopsPicosun / SisTEM Technology – Malcolm RowntreeStrem Inc/Ultra Tech – Ephraim HonigTyndall - Alan Blake Michael Burke