Atomic Layer DepositionAtomic Layer Deposition …

1 Atomic Layer DepositionAtomic Layer Deposition (ALD)Erwin Kessels phase Deposition technologiesPhysical Vapor Deposition (PVD) sputtering Chemical Vapor Deposition (CVD) Energetic ions!Heat!/Applied Physics - Erwin KesselsgMore applications have stricter requirements growth and thickness control 2Hi hflit / conformality/step uniformity on large substrate temperatures/Applied Physics - Erwin KesselsVery demanding applicationsNanoelectronicsPhotovoltaics fProtective thin filmsFlexible electronics/Applied Physics - Erwin KesselsCMOS scaling in nanoelectronics??????graphenegrapheneAct ive AreaGateFi el dSpacersActive AreaGateFi el dSpacersActive AreaGateFi el dSpacers????????????

2 Active AreaGateFi el dSpacersActive AreaGateFi el dSpacersActive AreaGateFi el dSpacersGe/IIIVGe/IIIV nanowiresnanowiresgpgpHfOmetal gatemetal gateFinFETFinFETL=35nmSiGeL=35nmL=35nmSi GestrainstrainHfO2high high -- timesilicidesilicideUSJUSJT imeeCourtesy of Marc Heyns, IMEC/Applied Physics - Erwin KesselsField-effect transistor: replacing SiO2by HfO232 nmThermally grown SiO2 Thermally grown SiO2/Applied Physics - Erwin KesselsPrecise Deposition of nanometer-thick Hf-based .comField-effect transistor: going from 2D to 3D gates22 nmPrecise Deposition of nanometer-thick Hf-based oxides with excellent conformality/Applied Physics - Erwin Kesselswith excellent . Layer Deposition (ALD): basics and key & ALD surface applications of developments in high-throughput ALD/Applied Physics - Erwin KesselsAtomic Layer Deposition (ALD) Reactants (precursors) are pulsed into reactoralternatelyandcycle-wise( ) Precursors react throughsaturative(self-limiting) surface reactions Asub-monolayerof material depositedper cycle/Applied Physics - Erwin KesselsALD of Al2O3films: Al(CH3)3-H2O process/Applied Physics - Erwin KesselsThickness vs.

3 Number of cyclesFilm thicknessis ruledby the number of cycleschosen30 1. Al(CH3)32 SiH{N(CH)}H3 CAlCH3CH3N(C2H5) )2. SiH2{N(C2H5)}23 T{N(CH)}N(CH3)2 SiHHN(C2H5) (nm3. Ta{N(CH3)2}5(H3C)2 NTaN(CH3)2N(CH3)2(3)2N(CH3)210 Thickn4. Zn(CH2CH3)2H3CH2 CZnH2 CCH30501001502002500 ALD C l5. Ti(Cp*)(OCH3)3 TiH3 COOCOCH3H3 CCH3CH3H3 CCH3+ /Applied Physics - Erwin KesselsPotts et al., J. Electrochem. Soc., 157, P66 ( 2010).Dingemans et al., J. Electrochem. Soc. 159, H277 (2012)ALD CyclesH3 COOCH3+ H2O, O3, or O2 plasmaKey features of of film growth and thickness Digital thickness conformality/step coverageSelf-limiting surface reactions3 Gdifitlb t uniformity on large substrates300 mm and even substrate temperaturespBetween 25 - 400 structures and nanolaminatesEasy to alternate between set of materials and processesManydifferent materials demonstratedMany different materials demonstrated/Applied Physics - Erwin KesselsLine-of-sight vs.

4 Conformal growth/Applied Physics - Erwin KesselsMaterials deposited ALD/Applied Physics - Erwin KesselsPuurunen, J. Appl. Phys. 97, 121301 (2005)Miikkulainen et al., J. Appl. Phys. 113, 021301 (2013). Layer Deposition (ALD): basics and key & ALD surface applications of developments in high-throughput ALD/Applied Physics - Erwin KesselsSingle wafer ALD reactorShower head reactor(warm or hot wall reactor)Flow-typereactor(hot wall reactor) TemporalALDPlti f Pulse-train of precursors Reactor pressure 1-10 Torr Applications: semiconductor (logic)/Applied Physics - Erwin Kesselspp(g)Batch ALD reactorTemporalALDB atchreactor TemporalALD Typically50-500 substrates in a single Deposition run Single-side Deposition can be challenginggpgg Applications.

5 Semiconductor (memory),displays,solar cells, Physics - Erwin KesselsPlasma ALD reactorsPlasma-assisted ALD can yield additional benefits for specific materialproperties at lower temperatures (also room temperature)DirectplasmaRemoteplasmapp(p ) growth rates/cycle and shorter cycle versatility/freedom in process and materials plasmaSubstrate part of plasma creation zoneRemote plasmaSubstrate downstream of plasma creation zone/Applied Physics - Erwin KesselsHeil et al., J. Vac. Sci. Technol. A 25, 1357 (2007).Profijt et al., J. Vac. Sci. Technol. A 29050801 (2011)Plasma-based chemistry (metal oxides) (CH3) (C2H5)220Al2O3 TiO2- Ti(OiPr)4 e)SiH2{N(C2H5)} { N(CH3)2}5(H3C)2 NTa(C)N(CH3)2N(CH3)2 SiHHN(C2H5) ()4 SiO2 TiO2 - Ti(CpMe)(OiPr)3Ta2O5 TiO2 - Ti(Cp*)(OMe)3e ( /cycle(3) (OiPr)4N(CH3)2N(CH3) (CpMe)(OiPr) (Cp*)(OCH) Temperature ( C)/Applied Physics - Erwin KesselsTi(Cp*)(OCH3)3 TiH3 COOCH3 OCH3H3 CCH3 Potts et al.

6 , J. Electrochem. Soc., 157, P66 ( 2010).Dingemans et al., J. Electrochem. Soc. 159, H277 (2012)Oxford Instruments OpAL reactor Plasma ALD/Applied Physics - Erwin KesselsALD equipment suppliers (incomplete list)SemiconductorSolar / R2RR&D / Pilot/Applied Physics - Erwin Layer Deposition (ALD): basics and key & ALD surface applications of developments in high-throughput ALD/Applied Physics - Erwin KesselsMetalorganic and H2O: ligand exchange (Al2O3) Al(CH3)3exposurePurge10-8 HOry signal (A)Al(CH3)3Al(CH3)3Al(CH3)3Al(CH3)3H2OH2 OH2OH2O10-8 HOry signal (A)10-8 HOry signal (A)Al(CH3)3Al(CH3)3Al(CH3)3Al(CH3)3H2OH2 OH2OH2O10-1010-9H2O spectrometrCH410-1010-9H2O spectrometrCH410-1010-9H2O spectrometrCH4 AlOH*+Al(CH3)3 AlOAl(CH3)2*+CH4 Cycle025507510010-11 Mass Time (s)4025507510010-11 Mass Time (s)4025507510010-11 Mass Time (s)4 AlOH Al(CH3)3 AlOAl(CH3)2 CH4 Surface chemistryrules ALD process.

7 Ligandexchange between Al(CH)andAlOH* + CH4 AlCH3* + H2O ligand exchange between Al(CH3)3and OH surface groups and H2O and CH3surface groups leads to CH4reaction products* are surface speciesH2O exposurePurge/Applied Physics - Erwin KesselsMetalorganic and H2O: ligand exchange (Al2O3) Al(CH3)3exposurePurge10-8 HOry signal (A)Al(CH3)3Al(CH3)3Al(CH3)3Al(CH3)3H2OH2 OH2OH2O10-8 HOry signal (A)10-8 HOry signal (A)Al(CH3)3Al(CH3)3Al(CH3)3Al(CH3)3H2OH2 OH2OH2O10-1010-9H2O spectrometrCH410-1010-9H2O spectrometrCH410-1010-9H2O spectrometrCH4 Cycle025507510010-11 Mass Time (s)4025507510010-11 Mass Time (s)4025507510010-11 Mass Time (s)4 Surface chemistryrules ALD process: ligandexchange between Al(CH)andligand exchange between Al(CH3)3and OH surface groups and H2O and CH3surface groups leads to CH4reaction productsH2O exposurePurge/Applied Physics - Erwin KesselsMetalorganic and H2O: ligand exchange (Al2O3) 4x10-5rbance2940 cm-11207 cm-1Al(CH3)3chemisorptionAl(CH3)3exposur ePurge frared absoOH stretchingCHxstretchingCHxdeformation294 0 cm11207 cm1HO4000 3500 3000 2500 2000 1500 1000 InWavenumber (cm-1)H2 OexposureCycleSurface chemistryrules ALD process: Surfacealternately covered by OHSurface alternately covered by OH surface groups and CH3surface groups/Applied Physics - Erwin KesselsH2O exposurePurgeMetalorganic and H2O.

8 Ligand exchange (Al2O3) Cycle ( )Al(CH3) owth per (CH3)3 dose (ms)CycleConditions such that precursors react throughsaturative surface reactions:Al(CH3)3does not react with CH3surface groups/Applied Physics - Erwin KesselsH2O exposurePurgeMetalorganic and H2O: ligand exchange (Al2O3) ycle ( )Al(CH3) wth per dose (ms)CycleConditions such that precursors react throughsaturative surface reactions:H2O does not react with OH surface groups/Applied Physics - Erwin KesselsH2O exposurePurgeMetalorganic and H2O: ligand exchange (Al2O3) cle ( )Al(CH3) wth per CycCVD+ after Al(CH3)3 dose (s)CyclePrecursors and reactants should be very well evacuated/separated from reactor before pulsing the next precursor/reaction:Otherwise parasitic CVD/Applied Physics - Erwin KesselsH2O exposurePurgeALD process: saturation curves (Al2O3)(a) (nm/cycle)Thermal ALD -Al(CH3)3& wth per Cycle ( CVDS ubsaturationCVD 020le)(b) time (ms)012345 Purge time (s)0 20406080H2O dose (ms)0123 Purge time (s)Plasma ALD -Al(CH3)3& Cycle (nm/cycl Subsaturation0 per C0123450123450123 CVD/Applied Physics - Erwin KesselsDose time (ms)Purge time (s)Plasma time (s)Purge time (s)ALD process.)

9 Substrate temperature (Al2O3)e) Plasma ALD Thermal ALDe (nm/cycle(a) Growth rate3456(b) per cycle cm-2)0123 # Al atoms (1015 c01002003004000 Substrate temperature (oC)AlOH* + Al(CH3)3 AlOAl(CH3)2* + CH4/Applied Physics - Erwin Kessels(3)3(3)24 AlOH* + CH4 AlCH3* + H2O Van Hemmen et al., J. Electrochem. Soc. 154, G165 (2007)Potts et al., J. Electrochem. Soc., 157, P66 ( 2010).ALD process: substrate temperature (ideal case)ALD Temperature Window thermal per TSubstrate Temperature Substrate/film surface/Applied Physics - Erwin KesselsMetal halide: ligand exchange (HfO2and TiN)HfOH*+HfClHfOHfCl*+HClMetal oxides: ligand exchangeHfOH* + HfCl4 HfOHfCl3* + HClHfOH* + HClHfCl* + H2O TiNH*+TiClTiNTiCl*+HClMetals nitrides: ligand exchangeTiNH + TiCl4 TiNTiCl3 + HClTiNH2* + HClTiCl* + NH3/Applied Physics - Erwin Kessels* are surface speciesMetals: combustion (Pt) and reduction (W)Noble metals: combustion by chemisorbed O23 O* + 2 (MeCp)PtMe32 (MeCp)PtMe2* + CH4 + CO2 + H2O 2 Pt* + 3 O* + 16 CO2 + 13 H2O2 (MeCp)PtMe2* + 24 O2 PtMetals.

10 Fluorosilane elimination reactionsWSiFH*+WFWWF*+SiFHWSiF2H + WF6 WWF5 + SiF3 HWSiF2H* + SiF3H + 2H2 WWF5* + Si2H6/Applied Physics - Erwin Kessels* are surface speciesPlasma-based chemistry (Al2O3and TiN)Metal oxides: combustionAlOH*+ Al(CH3)3 AlOAl(CH3)2* + CH4 AlOH* + CO2 + H2 OAlCH3* + 4O Metal nitrides: ligand exchange and reductionTiNH*+TiClTiNTiCl*+HClTiNH + TiCl4 TiNTiCl3 + HClTiNH2* + HClTiCl* + 3H + N/Applied Physics - Erwin Kessels* are surface speciesALD of doped films, ternary compounds, Physics - Erwin KesselsALD of Al-doped ZnO films Zn(C2H5)2+ H2 OZnO + 2 C2H6 ZnOZnO:Alncycles ZnO + mcycles Al2O3101 150 CAl2O3 TMA or DMAI + H2O 100 TMA cm)210-1 sistivity ( 05101520253010-310-2 ResDMAI/Applied Physics - Erwin KesselsWu et al.