H. Aülich PV Silicon AG Erfurt, Germany

Workshop on "Physics for Renewable Energy" October 17-29, 2005 301/1679-28 "Technology of Solar-grade Silicon" H. Aülich PV Silicon AG Erfurt, Germany

Silicon for the PV Industry Hubert A. Aulich PV Crystalox Solar AG F.-W. Schulze PV Silicon AG Workshop on Physics for Renewable Energy, Trieste October 24, 2005 Page 1

OVERVIEW PRESENTATION INTRODUCTION LONG-TERM SCENARIO REQUIREMENTS FOR DYNAMIC GROWTH - TECHNOLOGY - MARKETS CONCLUSIONS Workshop on Physics for Renewable Energy Page 2

Long-term Scenario Page 3

Solar power (PV and Thermal) will become the dominating energy source within this century energy demand per year [EJ/a] geothermal other renewables solar thermal (heat only) solar power (PV and solar thermal generation) 1400 1000 wind biomasse (advanced) biomasse (traditional) hydroelectricity nuclear power gas coal oil 600 200 Source: German Advisory Council on Global Change, 2003 2000 2020 2040 2100 www.wbgu.de year Market and Application Sustainable energy path Page 4

Time period considered 2000 2040 Wafer-based technology No quantum leaps, steady progress, known physics Growth rate world-wide module shipment according EPIA-study Price-learning curve for competitiveness Basic Assumptions Long-term Scenario Page 5 Page 5

TWh World electricity production from 2000 to 2040 100000 10000 World Electricity from PV in TWh 1000 World Electricity Generation in TWh 100 10 1 2000 2002 Market and Applications 27% 34% 15% Growth 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 2032 2034 2036 2038 2040 2020: PV 1% world electricity 2040: PV 26% world electricity Source :Solar Generation and IEA-PVPS Page 6

10.000,0 GWp/a 1.000,0 100,0 10,0 34% 15% 15% 1,0 0,1 27% Solar-Grade Silicon 2000 2010 2020 2030 2040 to/a 4.500 29.500 300.000 1.200.00 5.250.000 to/mwp 17,5 10,0 5,2 3,5 2,5 Installed Module Capacity and Silicon Consumption Page 7 Page 7

MWp 1200 1000 1000 800 600 523 680 400 200 135 176 253 344 0 1998 1999 2000 2001 2002 2003 2004 est. Source: Strategies Unlimited, PVCS World-Wide Cell & Module Shipments 1998-2004 Page 8

No bottlenecks seen for long-term, large scale PV Solar Electricity generation using crystalline Si-wafer technology Major thrust high efficiency at low cost Page 9 Page 9

Technology Page 10

To reduce cost in the long-term scenario technology advancements in all areas are necessary: Solar-grade silicon Crystallization Wafering Solar cells Modules Technology Advancements Page 11 Page 11

Production Capacity appr. 31,000 t/ p.a. IC s Off-spec poly-si 2,000 t (2004) Solar-gradeo Si 9,000 t (2004) Standard Silicon Production - Supply for PV Industry Page 12

SOLAR-GRADE SILICON Gas phase deposition Purify MG-Silicon Page 13

SOLAR-GRADE SILICON No clear definition exists as to the purity level of solar-grade silicon Most frequent usage: p-type 0.5 10 Ω cm slight compensation acceptable carbon concentration < 5 x 10 16 (Cz mc EFG) metal impurities < 1ppm SOLAR GRADE SILICON Page 14 Page 14

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Physicochemical Purification Process Quarzite Coke MG-Si Chemical Reaction HCI SiCl 4 SiHCl 3 SiH 2 Cl 2 Purification Conversion SiHCl 3 SiH 4 Thermal Decomposition CVD Solar Grade Silicon Mod. EG- Silicon Major new investment into conventional Siemens-type deposition, modified EG-Si. Capable semiconductor usage. Fluidized bed reactor appears to offer little price advantage Purified MG-Si usage not yet clear. From Quartz to Solar-Grade Silicon Page 16

CONVENTIONAL BELL JAR GROWING OF POLYSILICON THE CONTINUOUS IMPROVEMENT GOES ON. Silicon chips Silicon rod Silicon (slim) rod Solar-grade silicon CRUSHING 1000 C CRUSHING HF/HNO 3 ETCHING TCS + H 2 Prime polysilicon Exhaust Gas Electrical Power Feedstock for the PV Industry Karl Hesse, Ewald Schindlbeck, April 11 2005

FLUIDIZED BED GRANULAR DEPOSITION: A CONTINUOS PROCESS Exhaust gas Milling system Seed particles 700 µm Particle growth Quartz tube H 2 Reaction zone Heating zone Resistive heater Packaging Granular silicon TCS + H 2 H 2 Feedstock for the PV Industry Karl Hesse, Ewald Schindlbeck, April 11 2005

The Si Liquid runs from Reactor Tube just like a Tap Water TCS / H2 Graphite Tube [ Vapor to Liquid Deposition ] Induction Heating Coil Deposition Temperature is Higher than Si Melting Point Continuous Production of Granular Si Exhaust Gas Molten Silicon

Physicochemical Purification Process Quarzite Coke MG-Si Chemical Reaction HCI SiCl 4 SiHCl 3 SiH 2 Cl 2 Purification Conversion SiHCl 3 SiH 4 Thermal Decomposition CVD Solar Grade Silicon Mod. EG- Silicon Major new investment into conventional Siemens-type deposition, modified EG-Si. Capable semiconductor usage. Fluidized bed reactor appears to offer little price advantage Purified MG-Si usage not yet clear. From Quartz to Solar-Grade Silicon Page 20

Arc furnace metallurgical grade silicon chemical/physical treatment directional solidification solar grade silicon feedstock Solar grade silicon from metallurgical grade Page 21

DECREASE SILICON CONSUMPTION Crystallization Wafering Solar Cell Page 22

Total Silicon Yield From Feedstock To Wafer 32-54% SINGLE-CRYSTAL INGOT CZ-Pulling Cutting MULTI-CRYSTALLINE Solar-Si Blocks Wire sawing Directional Solidification Cropping Blocking Silicon Yield: Si-Recycle: 90%-95% Pot Scrap 80%-95% Cropped Section (Tops and tails,slabs) 45%-60% Broken Wafer Silicon Yield Page 23

Cz Multiple ingots from one crucible Mc Taller and larger ingots EMC Continuos casting Low cost / Wp Reduction of Silicon Consumption Page 24

Decrease spec. Silicon consumption from ca. 13 g/wp to < 5 g/wp Increase solar cell efficiency from av. 14.5 % up to 22 % and beyond Reduction of silicon consumption Page 25

Page 26 100 µm Thin and Flexible Wafer as Cut Page 26

100 X 100 mm 312 X 312 mm Development Wafer Format Page 27

Module efficiency up to 21 % Lifetime expectancy 35 years Building integrated Advancements in Module Technology Page 28 Page 28

100% Price-Experience Curve For PV Modules 10% 330 µm Waferthickness 70 µm 20 % 15 % 20 % 15 % Efficiency 22 % 1% 1 10 100 1.000 10.000 100.000 Cumulative installed GWp today PV Contribution Total Electricity 2020 1 % 2040 26 % Long Term Development PV Solar Electricity Page 29 Page 29

THIN FILM TECHNOLOGY Page 30

100 % 100 % 100 % Market Share 50 % 50 % 50 % YEAR 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Total 43 MWp Thin Film C-Si 680 MWp 1200 MWp (est.) Source: Strategies Unlimited Development Market Share C-Si vs. Thin Film Page 31

Markets Production Site PV Crystalox Solar Page 32

Off-Grid / remote industrial On-Grid Off-Grid / rural electrification Consumer Market and Applications Page 33

Solar cell producers worldwide Market Share in Solar Cells in 2004 (1200 [MWp]) Suntech 3% Motech 3% Isofoton 4% RWE Schott Solar ROW 22% 5% Sanyo 5% Shell Solar 6% Q-Cells 6% Sharp 25% Mitsubishi 6% Kyocer 8% BP Solar 7% Some of the large cell producers have wafering capacities but are increasingly outsourcing wafer production Some cell producers entirely outsource wafer production New solar cell producers mainly purchase wafers Source: Photon International, 2005, own estimates Market and Applications Page 34

According to our estimate silicon production might grow by ca. 30 % p.a. Demand by our customers much higher 44,000 40,000 Solar grade poly-si off-spec 36,000 32,000 28,000 24,000 20,000 16,000 12,000 8,000 4,000 Source: PV Silicon 0 0 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Silicon Supply Page 35

CONCLUSIONS Crystalline silicon wafer technology to dominate solar electricity for power applications in the foreseeable future Silicon likely to remain the fuel of the future Page 36