MOCVD mass production for cost efficient solar cell Dr. Frank Schulte AIXTRON AG
Outline AIXTRON: Company, Business and Products The Solar Cell Market Cost Reduction in MOCVD production Conclusion 29.10.2008 2 confidential
AIXTRON: Company, Business and Products The Solar Cell Market Cost Reduction in MOCVD production Conclusion 29.10.2008 3 confidential
Global Presence Global Customers Global Growth Markets AIXTRON Inc. Sunnyvale, CA, USA AIXTRON Ltd. Cambridge, UK AIXTRON AG Aachen, Germany Headquarters AIXTRON Europe Epigress AB Lund, Sweden AIXTRON Korea Co. Ltd. Seoul, South Korea AIXTRON AG Shanghai, P.R.China AIXTRON KK Tokyo, Japan AIXTRON Taiwan Co. Ltd.; Hsinchu Representation 29.10.2008 4 confidential
One Technology Multiple Solutions Business Technology Applications 29.10.2008 5 confidential Gas Phase Deposition Nano Scale Material Engineering Compound Semiconductors MOCVD, OVPD LEDs/OLEDs for displays LEDs/OLEDs for lighting III-V Compound and Organic solar cells Optoelectronics for telecom/datacom Organic Electronics for flexible displays and RFID CD-, DVD-lasers High frequency for wireless High power SiC Carbon Nanotube Structures Silicon Semiconductors AVD, ALD, CVD Metal and oxide films for CMOS transistors Traditional NAND-Flash Memory Traditional, next generation DRAM Memory TFH Thin Film Heads for data storage hard disk drives
Global MOCVD Market Shares 2005 Total: $156m 6% 13% 17% 64% AIXTRON Veeco Nippon Sanso Others 2006 Total: $202m 20% 14% 4% 62% 18% 2007 Total: $289m 10% 2% 70% Source: VLSI RESEARCH Inc. 2008 29.10.2008 6 confidential
AIXTRON: Company, Business and Products The Solar Cell Market Design, Growth and Cost Reduction in MOCVD production Conclusion 29.10.2008 7 confidential
AIXTRON s Mission to Mars Space Application 29.10.2008 8 confidential
Roadmap for Development of Solar Cells for Space Applications Source: Man Tech for Multi-Junction Solar Cells (http://www.afrlhorizons.com) Fraunhofer ISE/ RWE Solar (27.1%) Spectrolab (29%) 29.10.2008 9 confidential
165.000 Terra Watt free Solar Energy per Day arriving the earth catch something from this.. 29.10.2008 10 confidential
Future Energy Supply - Photovoltaic Electricity Possible Scenario for Europe in 2050 Primary energy use EJ/a solar cells on every roof Key-Technology: III-V Concentrator Multi Junction Photovoltaic Devices solar power plants 29.10.2008 11 confidential
Solar cell development 1-junction 6-junction GaAs GaAs η ~ 24.2 % AM1.5g GaInP GaInAs GaAs η ~ 31.1 % 300xAM1.5d GaInP GaInAs active Ge η ~ 27.1 % AM0 RWE/ISE AlGaInP GaInP AlGaInAs GaInAs active Ge AlGaInP GaInP AlGaInAs GaInAs GaInNAs active Ge half current double voltage 29.10.2008 12 confidential
Requirements for MOCVD of PV Devices High Efficiency & Long Lifetime; FF Determined by Device design & material quality: Minimized Energy Losses Suppress Thermal Losses : band gap design Suppress Recombination Losses: Layer Quality, Device Design Minimized mechanical stress for device on thin Ge (plastic phase): No strong mechanical forces Curvature control for metamorphic growth Multi Junction Cells need good junction between cells: Tunnel Diodes Tunneling requires sharp interfaces for doping, composition, thickness, low series resistance FF= blue/yellow area optimum = 1; realistic = 0.8 29.10.2008 13 confidential
Requirements for MOCVD of PV Devices Multi-Junction Solar Cell Structure MOCVD requirements: Crystalline quality Material purity interface quality Uniformity Film thickness Film composition Doping 29.10.2008 14 confidential
High Efficiency SC - Lowest Oxygen &Carbon Al.85Ga.15As SIMS Results AlAs/Al 0.12 Ga 0.88 As DBR grown at IQE with EpiPure TM TMA Oxygen concentration as low as detection limit Suppression of nonradiative recombination for highest Device Efficiency 29.10.2008 15 confidential
Planetary Reactor sharpest interfaces 29.10.2008 16 confidential X-ray measurement (straight line) and fit (dotted line) of two InGaAs QWs followed by a GaAsP strain compensating layer. Planetary Reactor enables sharpest interfaces Source: Feedback controlled growth of strain-balanced InGaAs multiple quantum wells in metal-organic vapour phase epitaxy using an in situ curvature sensor MZorn1, F Bugge1, T Schenk2, U Zeimer1, M Weyers1 and J-T Zettler2 1 Ferdinand-Braun-Institut f ur H ochstfrequenztechnik (FBH), Gustav- Kirchhoff-Str. 4, D-12489 Berlin, Germany 2 LayTec GmbH, Helmholtzstr. 13-14, D- 10587 Berlin, Germany
p++ - Al 0.185 Ga 0.815 As Carbon-Auto doping Res. Uniformity (Lehighton) < 3 % 2,10E+20 p++ AlGaAs (intrinsic) n [cm-³] 1,90E+20 1,70E+20 1,50E+20 1,30E+20 1,10E+20 9,00E+19 7,00E+19 5,00E+19 y = 2E+20x -1,1575 Very sensitive to T-Uniformity 1 1,2 1,4 1,6 1,8 2 2,2 2,4 2,6 V/III - ratio p++ doping calibration for Tunnnel Diode ( measured by XRD) 29.10.2008 17 confidential Planetary Reactor enables precise control of doping
P: 18 confidential jh1 AlGaInP: PL Wavelength Distribution - no edge exclusion - Std Dev: 0.06% (0.37 nm) Unmatched uniformity Date: 29.10.2008 Planetary Reactor
Folie 18 jh1 jhofeldt 18.10.2006 Ergebnis aus Labordemo 248G: Run G1384_7 jhofeldt; 19.10.2006
Requirements for PV Mass Production Highest process performance 29.10.2008 19 confidential Wide process window, excellent process stability Unmatched uniformities (Yield) and material quality Metamorphic growth on Ge Lowest Cost of Ownership (CoO) Highest throughput Highest material efficiency Low maintenance
AIXTRON: Company, Business and Products The Solar Cell Market Cost Reduction in MOCVD production Conclusion 29.10.2008 20 confidential
Cost reduction in MOCVD production Cost of Ownership Throughput Substrate area per Run Cycle time Uptime Yield Uniformity Defects Reliability Running costs per wafer area Consumables Precursor, gases Parts Design!! 29.10.2008 21 confidential
For design optimization modelling and simulation Guidance for reactor and process development Reduced risk in prototyping and design Speed-up of time to market Need for modelling in the industry is clearly driven by Reduction of Cost of Ownership (CoO) (e. g. by larger wafer load capacity, lower gas consumption, increased through-put, expanded usable wafer area) Enhancement of process performance (e. g. enable challenging process regimes) Improvement of process robustness (e. g. run-to-run uniformity, sensitivity to process variations) 29.10.2008 22 confidential
Scope of modelling and simulation Analysis of transport and reaction phenomena: Flow dynamics laminar and mixed convective flow Heat transfer & thermal management conduction / convection thermal radiation inductive, resistive, and lamp heating Used also in the Apollon Grant Agreement no. 213514 Growth chemistry multicomponent diffusion (e. g. H 2, N 2, NH 3, group-iii alkyls) reaction kinetics nucleation dynamics thin film deposition Computed flow field at inlet zone of the Planetary Reactor 29.10.2008 23 confidential
AIXTRON s New GaAs Mass Production Reactor Planetary Reactor 29.10.2008 24 confidential AIX2800G4-R providing Highest throughput Best Production Stability & Performance Best Cost of Ownership Dedicated to Highest Commercial Benefit
Cost reduction in MOCVD production Cost of Ownership Throughput Substrate area per Run Cycle time Uptime 29.10.2008 25 confidential
Planetary Reactor principle AsH 3 TMGa = Ga(CH 3 ) 3 carrier + group V elements wafer injector rotating infrared/inductive heated wafer carrier carrier + group III elements + dopants quartz glass ceiling Radial flow Rotating substrates Separate inlets 29.10.2008 26 confidential
18x3 11x2 12x4 5x6 35x2 24x2 8x4 7x6 49x2 8x4 29.10.2008 27 confidential
Cost reduction in MOCVD production Cost of Ownership Throughput Substrate area per Run Cycle time Uptime 29.10.2008 28 confidential
High Growth Rate GaInAs (In=1%) Growth Growth Rate Rate [µm/h] [µm/h] 16 14 14 12 12 10 10 8 6 4 2 0 Comparison 15x4 to 12x4inch: with same molar flow similar growth rates 29.10.2008 29 confidential 0 500 1000 1000 1500 1500 2000 2500 3000 3000 3500 3500 Molar Flow [µmol/min]
AIX 2800G4-R including Automated Satellite Handler: Gate Mechanism 29.10.2008 30 confidential
AIX 2800G4-R including Automated Satellite Handler: Satellite Exchange 29.10.2008 31 confidential
Planetary Reactor AIXTRON s New GaAs System Dedicated to Highest Commercial Benefit Higher Throughput shorter cycle time: Automated Satellite Loader Increased wafer capacity: 60x2/15x4inch Less Maintenance Downtime Increase hardware uptime: Graphite Ceiling no calibration/conditioning runs: Graphite Cover Star Enhanced Uniformity / Efficiency Improved process performance and stability: Triple Gas Injector 29.10.2008 32 confidential AIX2800G4 R dedicated to Highest Commercial Benefit
Cost reduction in MOCVD production Cost of Ownership Throughput Substrate area per Run Cycle time Uptime Yield Uniformity Defects Reliability Running costs per wafer area Consumables Precursor, gases Parts Design 29.10.2008 33 confidential
Al 0.14 GaInP Bulk material PL Uniformity Scan 2inch 0mm edge exclusion 60x2inch 29.10.2008 34 confidential Av. Wavelength 605.6nm stdev. 0.444nm Av. Wavelength 605.6nm stdev. 0.671nm Av. Wavelength 605.4nm stdev. 0.743nm Av. Wavelength 605.4nm stdev. 0. 467nm Wafer to wafer uniformity: no detectable difference 2.4µm/h growth rate
Low Particle Density after Device growth Total number of particle: Ø(17-200µm) = 21 29.10.2008 35 confidential Enhanced by Wafer Handler Wafer ID
Solar Cell In-Situ Monitoring: EpiCurve TT LASER X D ( z ) substrate wafer (bent due to strain) 29.10.2008 36 confidential parallel laser beam susceptor T Method: distance variation of parallel laser beams Control of Strain during growth on Ge 2D CCD camera z
Strain Design by EpiCurve TT 29.10.2008 37 confidential Courtesy: M. Zorn, FBH Berlin, AIX 200/4 Strain Design layer by layer MQW 5.0nm InGaAs / 50nm GaAs
Cost reduction in MOCVD production Cost of Ownership Throughput Substrate area per Run Cycle time Uptime Yield Uniformity Defects Reliability Running costs per wafer area Consumables Precursor, gases Parts Design 29.10.2008 38 confidential
Stability after Reactor-Maintenance: AlGaInP-DH + exchange graphite star and ceiling AGIP-DH: PL wavelength NO edge exclusion PL lambda avg. [nm] 605 604,5 604 603,5 603 602,5 602 601,5 601 600,5 600 29.10.2008 39 confidential Ref. DH MQW Cover star exchange Ceiling exchange 128 129 130 131 132 133 134 135 136 137 138 run no. Pl avg. Lid open in GB PL max-min < 1nm Change of Wavelength after Maintenance NO CALIBRATION RUNS REQUIRED 7 6,5 6 5,5 5 4,5 4 3,5 3 2,5 2
Cost reduction in MOCVD production Cost of Ownership Throughput Substrate area per Run Cycle time Uptime Yield Uniformity Defects Reliability Running costs per wafer area Consumables Precursor, gases Parts Design 29.10.2008 40 confidential
Efficiency Data Efficiency Comparison precusor *all values calculated acc. to O. Kayser, Chemtronics 1988, Vol. 3, June, pp 90ff 29.10.2008 41 confidential 15x4inch 8x6inch 12x4inch AlAs/GaAs DBR GaInP AIX2800G4-R AlAs/GaAs DBR GaInP AlAs/GaAs DBR High Material Utilization in AIX2800G4-R AIX2600G3 GaInP TMGa 42.7% 39.9% 65.7% 60.9% 36.0% 38.0% TMAl 37.8% 52.8% 36.0% n.a. TMIn 34.2% 42.2% n.a. 33.0%
Conclusion Reliable mass production system fulfilling the CoO request is developed and in qualification for LED production Further qualification and optimization of design will be done adapted to the solar cell demand Like in the Appollon project with - Modelling - Hardware and insitu optimization - Solar Cell design 29.10.2008 42 confidential