Polysilicon for Solar Wafers - Markit · POLYSILICON FOR SOLAR WAFERS Report No. 272 by Anthony Pavone December 2009 Menlo Park, California 94025 Process Economics Program A private

© SRI Consulting PEP Report 272

Abstract Process Economics Program Report 272

POLYSILICON FOR SOLAR WAFERS (December 2009)

Silicon wafer based photovoltaic cells that absorb light photons and convert them to electricity (electrons) appear to be at the edge of commercial cost competitiveness (grid parity). The purity of silicon used to make solar wafers can be considerably lower than electronic grade silicon used to make semiconductors for micro processors, allowing for the use of lower manufacturing cost technologies such as Siemens reactors, fluidized bed reactors, and directional solidification furnaces. Solar cells are made from feedstocks such as upgraded metallurgical grade silicon, polysilicon, thin film amorphous silicon, thin film non-silicon metal complexes (cadmium telluride, cadmium indium gemanium selenide, etc.), and organo-metallics,

Two kinds of companies currently market commercial quantities of polysilicon used to produce solar wafers: 1) on-purpose producers starting with high purity quartz, trichlorosilane (or similar silicon containing gases) that produce polysilicon in high temperature furnaces, and 2) recyclers of electronic grade silicon that has been scrapped from discarded electronic products, or recovered as by-product waste from silicon production. We examine the purity requirements and processing schemes for producing solar grade polysilicon, and report on the corresponding economics.

Until year 2000, photovoltaic cells were produced primarily from electronic grade silicon. More recently, silicon based photovoltaic cells producers have learned how to produce the photovoltaic cells directly from polysilicon, thereby eliminating the costly last step of converting polysilicon first to higher purity single crystal silicon. Also commercialized recently is technology for producing ‘upgraded’ metallurgical silicon that can be blended into higher purity solar grade polysilicon and used to produce photovoltaic cells. There are claims that upgraded metallurgical silicon can be used directly (not blended) to form solar wafers. Directional solidification furnaces operating at high vacuum accomplish this objective.

We present in this report the process engineering technology and corresponding production economics for making at commercial scale ‘solar grade’ polysilicon via: 1) Siemens furnace technology (the market leader), and 2) fluidized bed reactor technology. We also present 3) the process design and corresponding techno-economics for producing upgraded metallurgical silicon ingots in a rotational solidification dimensional electric induction furnace operating at high vacuum.

SRIC agrees to assign professionally qualified personnel to the preparation of theProcess Economics Program’s reports and will perform the work in conformance with generallyaccepted professional standards. No other warranties expressed or implied are made. Becausethe reports are of an advisory nature, neither SRIC nor its employees will assume any liability forthe special or consequential damages arising from the Client’s use of the results contained in thereports. The Client agrees to indemnify, defend, and hold SRIC, its officers, and employeesharmless from any liability to any third party resulting directly or indirectly from the Client’s use ofthe reports or other deliverables produced by SRIC pursuant to this agreement

For detailed marketing data and information, the reader is referred to one of the SRIConsulting programs specializing in marketing research. THE CHEMICAL ECONOMICSHANDBOOK Program covers most major chemicals and chemical products produced in theUnited States and the WORLD PETROCHEMICALS PROGRAM covers major hydrocarbons andtheir derivatives on a worldwide basis. In addition the SRIC DIRECTORY OF CHEMICALPRODUCERS services provide detailed lists of chemical producers by company, product, andplant for the United States, Western Europe, Canada, and East Asia, South America and Mexico.

© SRI Consulting iii PEP Report 272

CONTENTS

1 INTRODUCTION ........................................................................................................ 1-1

GLOBAL ENERGY DEMAND .................................................................................... 1-1

WHAT IS POLYSILICON?.......................................................................................... 1-2

WHAT IS POLYSILICON USED FOR?...................................................................... 1-3

MAKING ELECTRICITY USING SOLAR WAFERS................................................... 1-3

POLYSILICON MANUFACTURING TECHNOLOGIES............................................. 1-4

POLYSILICON PURITY REQUIREMENTS ............................................................... 1-7

SCOPE OF THIS REPORT........................................................................................ 1-7

HISTORICAL BACKGROUND ................................................................................... 1-7

PHOTOVOLTAIC INTEGRATED PRODUCT CHAIN................................................ 1-8

FORMS OF SILICON BASED SOLAR WAFERS ...................................................... 1-11

ENERGY CONVERSION EFFICIENCY..................................................................... 1-13

MAJOR PV INDUSTRY PRODUCERS...................................................................... 1-14

POLYSILICON PRODUCER CAPACITY................................................................... 1-16

2 SUMMARY ................................................................................................................. 2-1

3 PROCESS SAFETY................................................................................................... 3-1

DESIGN AND ENGINEERING STANDARDS............................................................ 3-1

PROCESS SAFETY METHODOLOGY ..................................................................... 3-4

INCIDENT ANALYSIS ................................................................................................ 3-5

POLYSILICON INCIDENT RECORD......................................................................... 3-5

PROCESS SAFETY ANALYSIS ................................................................................ 3-7

HAZARDOUS OPERATIONS ANALYSIS (HAZOP).................................................. 3-9

METHODOLOGY FOR CONDUCTING HAZOP REVIEW AND ANALYSIS............. 3-15

PERSONAL PROTECTIVE EQUIPMENT (PPE)....................................................... 3-16

© SRI Consulting iv PEP Report 272

CONTENTS (Continued)

THE NFPA DIAMOND................................................................................................ 3-16

SILANE GAS EXPLOSION SAFETY ......................................................................... 3-17

STRONG ACIDS AND ALKALIES.............................................................................. 3-19

CHLORINATED SILICON GASES............................................................................. 3-19

PROCESS EQUIPMENT LAYOUT AND STARTL-UP .............................................. 3-19

MATERIALS OF CONSTRUCTION ........................................................................... 3-19

SAFE CONTAINMENT............................................................................................... 3-20

FALL PROTECTION .................................................................................................. 3-20

SILICON DUST EXPLOSION POTENTIAL ............................................................... 3-20

ASPHYXIATION CONCERNS ................................................................................... 3-21

HYDROGEN GAS SAFETY ....................................................................................... 3-22

ELECTRIC FURNACE OPERATIONS....................................................................... 3-23

COLLISION HAZARDS .............................................................................................. 3-23

4 VALUE PROPOSITION FOR POLYSILICON ........................................................... 4-1

VALUE PROPOSITION COMPONENTS................................................................... 4-1

ADDRESSING PHOTOVOLTAIC COST COMPETITIVENESS ISSUES.................. 4-2

Feed-In Tariffs ............................................................................................................ 4-3

ACHIEVING 'GRID PARTIY' ...................................................................................... 4-5

IMPACT OF ECONOMIC INCENTIVES .................................................................... 4-6

WHERE PHOTOVOLTAICS ARE COMMERCIALLY COST COMPETITIVE ........... 4-8

TECHNOLOGY DRIVE PRODUCTION COST REDUCTIONS................................. 4-8

Quantum Dots............................................................................................................. 4-12

Building Integrated Photovoltaics (BIPV) ................................................................... 4-12

Aggregate Effect of Technology Improvements ......................................................... 4-12

INSTITUTIONAL BARRIERS TO COMMERCIALIZATION ....................................... 4-13

© SRI Consulting v PEP Report 272


Misrepresentation of Claims....................................................................................... 4-13

Technical Performance ........................................................................................ 4-14

Cost Competitiveness........................................................................................... 4-14

Durability............................................................................................................... 4-17

System Degradation Over Time ........................................................................... 4-17

Macro Economic Impacts ..................................................................................... 4-18

Benign Environmental Impact .............................................................................. 4-18

Energy Independence .......................................................................................... 4-19

Job Creation ......................................................................................................... 4-19

Overcoming Ancillary Facilities Liabilities................................................................... 4-20

Rooftop Fire Problems in Los Angeles....................................................................... 4-21

Certifying PV Performance (Industry Standards) ....................................................... 4-22

Providing Adequate Grid Transmission Capacity....................................................... 4-23

Financing Renewable Energy That Depends Upon Subsidies .................................. 4-24

Overcoming Local Environmental Opposition to Specific Project Plans .................... 4-24

Overcoming Stagnant Electrical Demand Markets .................................................... 4-25

ENVIRONMENT, HEALTH AND SAFETY (EHS) CONSIDERATIONS .................... 4-25

COMPETING AGAINST NON-SILICON PHOTOVOLTAIC TECHNOLOGIES......... 4-26

Cost Comparison of Polysilicon versus Thin Film PV Cells ....................................... 4-29

Organic PV Systems .................................................................................................. 4-30

SOLAR AMERICA BOARD FOR CODES AND STANDARDS.................................. 4-31

References ................................................................................................................. 4-31

IEC Standards ...................................................................................................... 4-31

EN Standards ....................................................................................................... 4-31

SEMI Standards ................................................................................................... 4-31

DIN/VDE Standards.............................................................................................. 4-32

5 INDUSTRY STATUS.................................................................................................. 5-1

FORMS OF COMMERCIAL POLYSILICON PRODUCED ........................................ 5-1

© SRI Consulting vi PEP Report 272


PROCESS EQUIPMENT PRODUCING ON-PURPOSE POLYSILICON.................. 5-1

Siemens Reactors ...................................................................................................... 5-1

Fluidized Bed Reactor ................................................................................................ 5-2

Directional Solidification Furnaces ............................................................................. 5-2

RECLAIM AND SCRAP SILICON MARKET.............................................................. 5-3

Size of Reclaim Silicon Market ................................................................................... 5-3

INTEGRATED PRODUCT CHAIN FOR POLYSILICON ........................................... 5-6

POLYSILICON PURITY ............................................................................................. 5-8

FORMS OF POLYSILICON SOLD............................................................................. 5-9

GROWTH OF THE ELECTRONIC CHEMICALS BUSINESS ................................... 5-9

MACROECONOMIC ENVIRONMENT....................................................................... 5-11

REGULATORY ENVIRONMENT ............................................................................... 5-12

PV MARKET REBOUND FROM 2008 GLOBAL RECESSION ................................. 5-13

SILICON VERSUS THIN-FILM COMPETITION ........................................................ 5-21

PHOTOVOLTAIC INDUSTRY MARKET LESSONS LEARNED................................ 5-21

MAJOR SOLAR PHOTOVOLTAIC COMPETITORS................................................. 5-22

Regional Distribution of Solar Wafer/Cell Capacity.................................................... 5-25

EQUIPMENT AND SERVICE SUPPLIERS (TOOL MAKERS).................................. 5-26

GLOBAL POLYSILICON SUPPLIERS....................................................................... 5-26

POLYSILICON PRODUCER DISCUSSION .............................................................. 5-28

ANNOUNCED POLYSILICON CAPACITY ................................................................ 5-29

POLYSILICON DEMAND........................................................................................... 5-33

POLYSILICON INDUSTRY CAPACITY UTILIZATION.............................................. 5-37

POLYSILICON PRICES ............................................................................................. 5-38

6 CHEMISTRY & PROCESS TECHNOLOGY FOR POLYSILICON PRODUCTION.. 6-1

© SRI Consulting vii PEP Report 272


SILICON PHYSICAL PROPERTIES .......................................................................... 6-1

SILICON PURITY OBJECTIVES................................................................................ 6-2

CRYSTALLINE STRUCTION OF SILICON ............................................................... 6-4

INTEGRATED PRODUCT CHAIN FOR POLYSILICON ........................................... 6-4

PRODUCING METALLURGICAL GRADE SILICON ................................................. 6-6

CARBON IMPURITIES............................................................................................... 6-7

DUPONT ZINC PROCESS ........................................................................................ 6-7

GAS PLANT CHEMISTRY ......................................................................................... 6-8

PRODUCTION OF TRICHLOROSILANE .................................................................. 6-8

Silane Production Chemistry for Fluidized Bed Reactors .......................................... 6-10

GAS PLANT PROCESS CONFIGURATIONS........................................................... 6-11

Hemlock Dichlorosilane Process................................................................................ 6-14

Union Carbide Silane Process ................................................................................... 6-15

SRIC Generic Gas Plant Process Configuration........................................................ 6-16

Anhydrous HCI Recovery ........................................................................................... 6-17

Proprietary Chemistry................................................................................................. 6-18

CLOSED LOOP GAS PROCESSING ........................................................................ 6-19

COMMERCIAL GAS PLANT OPERATIONS ............................................................. 6-19

Hydro-Chlorination Reactor ........................................................................................ 6-19

TCS Purification.......................................................................................................... 6-19

Vent Gas Recovery .................................................................................................... 6-19

Silicon Tetrachloride Converters ................................................................................ 6-20

SIEMENS PROCESS DEPOSITION CHEMISTRY ................................................... 6-20

FLUIDIZED BED REACTOR PROCESS ................................................................... 6-21

DIRECTIONAL SOLIDIFICATION FURNACE TECHNOLOGY................................. 6-22

PRODUCING SEMICONDUCTOR GRADE SILICON FROM POLYSILICON.......... 6-22

© SRI Consulting viii PEP Report 272



7 DESIGN BASIS FOR COMMERCIAL POLYSILICON PRODUCTION .................... 7-1

DESIGN PHILOSOPHY ............................................................................................. 7-1

DESIGN PRIORITIES ................................................................................................ 7-1

Safety.......................................................................................................................... 7-2

Reliability .................................................................................................................... 7-2

Environmental Conformance...................................................................................... 7-2

Flexibility for Economic Optimization.......................................................................... 7-3

Ease of Operations & Maintenance............................................................................ 7-3

Buildings ..................................................................................................................... 7-4

Security and Vulnerability Analysis ............................................................................ 7-4

PROJECT DESIGN CAPACITY................................................................................. 7-5

POLYSILICON DESIGN PURITY............................................................................... 7-5

LOCATION ................................................................................................................. 7-5

CONSTRUCTION METHODOLOGY......................................................................... 7-7

OFFSITE FACILITIES ................................................................................................ 7-7

Black Start Capability ................................................................................................. 7-9

Environmental Design Standards & Facilities ...................................................... 7-9

Reactor/Furnace Off-Gases ....................................................................................... 7-9

Miscellaneous Wastes................................................................................................ 7-10

Incineration ................................................................................................................. 7-10

Capacity Utilization Factor.......................................................................................... 7-10

Turndown Ratio .......................................................................................................... 7-10

Turnaround Frequency and Duration ......................................................................... 7-11

ENIGNEERING AND DESIGN STANDARDS............................................................ 7-11

Provide Machine Condition Monitoring Instrumentation............................................. 7-13

© SRI Consulting ix PEP Report 272


SITE SPECIFIC DESIGN CONDITIONS ................................................................... 7-13

Site Location ............................................................................................................... 7-14

CAPITAL AND OPERATING COST BASES.............................................................. 7-14

Capital Investment...................................................................................................... 7-14

CONSTRUCTION CAPITAL COST INDEX ............................................................... 7-16

PROJECT CONSTRUCTION TIMING....................................................................... 7-18

AVAILABLE UTILITIES .............................................................................................. 7-18

Production Cost Factors ............................................................................................. 7-18

FEEDSTOCK, PRODUCT AND ENERGY PRICING................................................. 7-19

Effect of Operating Level on Production Costs .......................................................... 7-19

PLANT LAYOUT AND REAL ESTATE REQUIREMENTS ........................................ 7-20

8 POLYSILICON RODS FROM TRICHLOROSILANE VIA SIEMENS CLOSED LOOP PROCESS .................................................................................................................. 8-1

HISTORICAL BACKGROUND ................................................................................... 8-1

SIEMENS REACTOR CONFIGURATION ................................................................. 8-1

FILAMENT ROD CONFIGURATION ......................................................................... 8-3

HAIRPIN FILAMENT RODS FOR SIEMENS FURNACES........................................ 8-4

CHARACTERISTICS OF SIEMENS REACTOR OPERATIONS............................... 8-5

OPEN LOOP VS CLOSED LOOP PROCESS........................................................... 8-6

SIEMENS REACTOR PROCESS CONDITIONS ...................................................... 8-7

SIEMENS REACTOR USERS ................................................................................... 8-8

SIEMENS REACTOR VENDORS.............................................................................. 8-9

SIEMENS REACTOR CAPACITY.............................................................................. 8-9

ELECTRICITY CONSUMPTION IN SIEMENS REACTORS..................................... 8-10

REACTOR CYCLE TIME ........................................................................................... 8-10

REACTOR INTERNALS............................................................................................. 8-10

© SRI Consulting x PEP Report 272


SIEMENS REACTOR DIMENSIONS......................................................................... 8-12

PROJECT DESIGN SCOPE OF WORK.................................................................... 8-12

PRODUCTION PLANT AND INDIVIDUAL REACTOR CAPACITY........................... 8-14

SIEMENS REACTOR PROCESS DESIGN BASIS.................................................... 8-14

Feed Gas Conditions.................................................................................................. 8-14

Reactor Operating Basis ............................................................................................ 8-14

Product Gas Filtration................................................................................................. 8-14

BLOCK FLOW DIAGRAM .......................................................................................... 8-16

PROCESS FLOW DIAGRAM AND DESCRIPTION .................................................. 8-17

STREAM-BYSTREAM MATERIAL BALANCE........................................................... 8-18

EQUIPMENT LIST...................................................................................................... 8-19

CAPITAL COST ESTIMATE....................................................................................... 8-19

MANUFACTURING COST ESTIMATE...................................................................... 8-22

Production Cost Elements .......................................................................................... 8-22

Variable Cost Analysis................................................................................................ 8-23

Total Production Cost Analysis .................................................................................. 8-24

Cash Cost Analysis .................................................................................................... 8-25

ECONOMIC ASSESSMENT ...................................................................................... 8-25

9 POLYSILICON BEADS FROM SILANE VIA FLUIDIZED BED REACTOR TECHNOLOGY .......................................................................................................... 9-1

PROCESS HISTORY ................................................................................................. 9-1

FLUIDIZED BED REACTOR DIMENSIONS.............................................................. 9-4

CLOSED LOOP PROCESS ....................................................................................... 9-5

BENEFIT OF PRODUCING BEAD AND/OR GRANULAR POLYSILICON............... 9-6

FLUIDIZED BED REACTOR OPERATION................................................................ 9-6

REACTOR DESIGN ZONES WITHIN FLUIDIZED BED............................................ 9-7

© SRI Consulting xi PEP Report 272


INTEGRATED SILANE AND FLUIDIZED BED REACTOR POLYSILICON PLANTS 9-8

REC Silicon Commercial Plants ................................................................................. 9-8

AE POLYSILICON FLUIDIZED BED REACTOR PROCESS .................................... 9-9


COMPARISON WITH SIEMENS REACTOR PERFORMANCE................................ 9-9

DESIRABLE DESIGN CHARACTERISTICS ............................................................. 9-10

PROCESS DESIGN GUIDANCE ............................................................................... 9-11

Feed Gas Composition............................................................................................... 9-13

Fluidized Bed Reactor Design Basis .......................................................................... 9-14

Unit Electricity Consumption....................................................................................... 9-14

Product Gas Filtration................................................................................................. 9-14

Start-Up and Purge Vacuum Pump............................................................................ 9-14

SEED PARTICLE PREPARATION ............................................................................ 9-15

ZONE HEATING OF THE FLUIDIZED BED .............................................................. 9-16

SILANE VERSUS TRICHLOROSILANE FEEDSTOCK............................................. 9-17

RECOVERING AND RE-USING SILANE DUST ....................................................... 9-17

WACKER'S FLUDIZDED BED REACTOR DESIGN ................................................. 9-17

USE OF COMBINED SIEMENS AND FLUIDIZED BED REACTORS ...................... 9-20

3-ZONE FLUIZIDE BED REACTOR .......................................................................... 9-21

PROPOSED PROCESS CONFIGURATION ............................................................. 9-21

NUMBER OF PARALLEL PROCESS TRAINS.......................................................... 9-22

CLEAN ROOM BUILDINGS....................................................................................... 9-22

PROCESS FLOW DIAGRAM AND PROCESS DESCRIPTION................................ 9-23

Fluidized Bed Reactor Section ................................................................................... 9-23

Cleaning and Packaging Section ............................................................................... 9-24

MATERIAL BALANCE................................................................................................ 9-25

© SRI Consulting xii PEP Report 272


PROCESS EQUIPMENT LIST................................................................................... 9-27




Variable Cost Analysis................................................................................................ 9-32



ECONOMIC ASSESSMENT ...................................................................................... 9-35

10 UPGRADED METALLURIGCAL GRADE SILICON VIA DIMENSIONAL SOLIDIFICATION HIGH VACUUM ELECTRIC INDUCTION FURNACE TECHNOLOGY .......................................................................................................... 10-1

INTRODUCTION ........................................................................................................ 10-1

PERFORMANCE OF SOLAR CELLS USING UMG-SI ............................................. 10-2

Calisolar / Timminco Relationship fro UMP-Si Supply ............................................... 10-2

VALUE PROPOSITION FOR UMG-SI ....................................................................... 10-4

COMPETING AGAINST UPGRADED METALLURGICAL GRADE SILICON........... 10-5

UMG-SI PRODUCT PURITY...................................................................................... 10-5

INTEGRATED PRODUCT CHAIN FOR UMG-SI ...................................................... 10-5

UMG-SI SUPPLIERS AND FURANCE VENDORS ................................................... 10-6

GT Solar ..................................................................................................................... 10-7

Timminco .................................................................................................................... 10-7

ALD DSS Vacuum Furnaces...................................................................................... 10-9

Centrotherm Multi-Crystalline Ingot Furnace ............................................................. 10-10

DESIGN CHARACTERISTICS OF UMG-SI FURNACES.......................................... 10-10

Crucible Loading......................................................................................................... 10-10

Crucible Design .......................................................................................................... 10-10

FURNACE PROCESSING STEPS ............................................................................ 10-11

© SRI Consulting xiii PEP Report 272


SLAGGIN AGENT ADDITION.................................................................................... 10-12

CONTINUOUS BLOWDOWN OF CRUCIBLE MELT ................................................ 10-12

PARTIAL SOLIDIFICATION OF SILICON MELT....................................................... 10-13

OTHER APPROACHES TO INCREASING PURITY USING INDUCTION FURNACES................................................................................................................ 10-13

PROCESS TECHNOLOGY FOR DSS FURNACE SYSTEM DESIGN ..................... 10-13

CRUCIBLE BINDING AND RELEASE AGENTS ....................................................... 10-17

REUSABLE CRUCIBLES........................................................................................... 10-18

POWER CONSUMPTION.......................................................................................... 10-18

PRODUCT SELECTIVITY.......................................................................................... 10-18

PROPOSED DESIGN PROCEDURE FOR MAKING UMG-SI .................................. 10-19

PROPOSED DESIGN DETAILS FOR DSS FURNACE PROCESS.......................... 10-20

Feedstock Supply ....................................................................................................... 10-20

Buildings ..................................................................................................................... 10-20

SCOPE OF PLANT OPERATION (BATTERY LIMITS) ............................................. 10-20

NUMBER OF ELECTRIC INDUCTION FURNACES................................................. 10-21

FURNACE SYSTEM OPERATING UNIT CONDITIONS........................................... 10-21

OPTIONS NOT INCORPORATED IN PROJECT DESIGN ....................................... 10-22

Continuous Melting Furnace ...................................................................................... 10-22

Pressurized Gas Melting and Crystalline ................................................................... 10-24

Rotational Solidification .............................................................................................. 10-24

Electromagnetic Stirring ............................................................................................. 10-25

PROCESS FLOW DIAGRAM & DESCRIPTION........................................................ 10-25

MATERIAL BALANCE................................................................................................ 10-26

EQUIPMENT LIST...................................................................................................... 10-27


© SRI Consulting xiv PEP Report 272




Variable cost Analysis ................................................................................................ 10-31



EQUIPMENT ASSESSMENT..................................................................................... 10-34

INDUSTRY REPORTED PRODUCTION ECONOMICS ........................................... 10-35

11 COMPETING TECHNOLOGIES TO PRODUCE SOLAR CELLS ............................ 11-1

THIN-FILM INORGANIC MATERIALS....................................................................... 11-1

THIN-FILM CELL CONVERSION EFFICIENCIES .................................................... 11-3

CONDUCTIVE ORGANIC POLYMERS..................................................................... 11-4

RECLAIMED SILICON ............................................................................................... 11-4

UPGRADED METALLURGICAL GRADE SILICON................................................... 11-5

COMPONENTS OF COST EFFECTIVENESS.......................................................... 11-5

12 RECENT TECHNOLOGY DEVELOPMENTS ........................................................... 12-1

ARISE TECHNOLOGY............................................................................................... 12-1

SOLAR GRADE POLYSILICON INGOT.................................................................... 12-1

ZINC REDUCTION IN FLUIDIZED BED REACTORS............................................... 12-1

NANOPILLAR SOLAR ARRAYS................................................................................ 12-2

MULTI JUNCTION (TANDEM JUNCTION) SOLAR CELLS (TRANSFER JUNCTION 12-2

SUBSTITUTING H2CL2SI FOR HCL3SI ..................................................................... 12-3

CARBON REPLACING SILICON............................................................................... 12-3

IMPROVING SIEMENS REACTOR PERFORMANCE.............................................. 12-3

STRING RIBBON SILICON........................................................................................ 12-4

RSI SILICON PROCESS............................................................................................ 12-5

© SRI Consulting xv PEP Report 272

CONTENTS (Concluded)

IMPROVING FLUIDIZED BED REACTOR PERFORMANCE................................... 12-5

FULL-SQUARE SOLAR WAFERS............................................................................. 12-5

ORGANIC PV CELLS AND SYSTEMS...................................................................... 12-5

MUTO SILICON CORP - SRI INTERNATIONAL PROCESS .................................... 12-6

APPENDIX A: PATENT SUMMARY TABLES.................................................................. A-1

APPENDIX B: CITED REFERENCES............................................................................... B-1

APPENDIX C: PROCESS FLOW DIAGRAMS ................................................................. C-1

© SRI Consulting xvi PEP Report 272

ILLUSTRATIONS

1.1 Historical Cost of PV Generation Systems............................................................ 1-2

1.2 Basic Photovoltaic Cell .......................................................................................... 1-3

1.3 Connecting the PV System to the Power Grid ...................................................... 1-4

1.4 Electron Source and Sink on a Solar Wafer.......................................................... 1-4

1.5 Silicon Gas Plant Manufacturing ........................................................................... 1-5

1.6 Polysilicon Manufacturing Share ........................................................................... 1-5

1.7 Polysilicon Processing Scheme ............................................................................ 1-6

1.8 Photovoltaic Product Chain ................................................................................... 1-8

1.9 Hemlock's Polysilicon Product Chain .................................................................... 1-9

1.10 Silicon Processing ................................................................................................. 1-10

1.11 Demand for PV Systems by Technology............................................................... 1-12

1.12 PV Market Share for Crystalline and Thin Films in the US ................................... 1-12

1.13 PV Technology Conversion Efficiencies ............................................................... 1-13

1.14 SRIC Forecast Market Share for PV Technologies............................................... 1-14

1.15 Major Polysilicon Producer Capacity..................................................................... 1-16

3.1 NFPA Diamond...................................................................................................... 3-17

4.1 Hemlock's Polysilicon Integrated Product Chain................................................... 4-1

4.2 Average US Residential Power Prices.................................................................. 4-5

4.3 Historical Cost of Photovoltaic Power ................................................................... 4-6

4.4 2008 Installed US PV Power by State................................................................... 4-7

4.5 2008 Installed Global PV Power............................................................................ 4-7

4.6 Nitol Solar Expectation of Average Wafer Thickness............................................ 4-11

4.7 Kerf Associated with Saw Blade Design ............................................................... 4-11

4.8 Production Cost of Electricity Generating Technologies....................................... 4-15

4.9 Residential PV Capacity Utilization Experience at PG&E..................................... 4-17

4.10 PV Group Assessment of Power Source Labor Intensity ..................................... 4-19

4.11 Cost Components of Silicon Based PV Modules .................................................. 4-27

© SRI Consulting xvii PEP Report 272

ILLUSTRATIONS (Continued)

4.12 Estelux Estimate of PV Technology Market Share ............................................... 4-27

4.13 Nitol Solar's Forecast of PV Technology Capacity................................................ 4-28

4.14 GTM Research PV Business Model Components ................................................ 4-29

5.1 2007 Worldwide Silicon Wafer Reclaim Market Distribution by Region................ 5-4

5.2 Reclaim Silicon Market by Company Headquarters.............................................. 5-4

5.3 Silicon Integrated Product Chain........................................................................... 5-7

5.4 Solar Wafer Polysilicon Purity Evolution ............................................................... 5-9

5.5 SRIC's Segmentation of Electronic Chemicals Business...................................... 5-10

5.6 SRIC's Forecast Growth for Specialty Chemicals................................................. 5-11

5.7 ChemicalWeek Magazine Estimate of 2008 PV Sales.......................................... 5-14

5.8 PV-Tech's Forecast of Industry Capital Investment .............................................. 5-15

5.9 iSupply Global PV Demand Forecast Before and After Reduction in Spanish Subsides................................................................................................................ 5-16

5.10 GTM Research Estimate of Global Capacity and Unit Capital Cost ..................... 5-17

5.11 GTM Research Forecast of Photovoltaic Capacity Growth .................................. 5-18

5.12 EPIA Forecast of Photovoltaic Capacity Growth................................................... 5-18

5.13 EPIA Forecast of Photovoltaic Product Chain Components ................................. 5-19

5.14 iSupply Forecast of Photovoltaic Demand Growth................................................ 5-20

5.15 Greentech Media Estimate of Thin-Film Market Share ......................................... 5-21

5.16 2008 Production of Photovoltaic Competitors ....................................................... 5-23

5.17 Installed 2008 Capacity of Photovoltaic Competitors............................................ 5-24

5.18 2007 Distribution of Solar Cell Capacity................................................................ 5-26

5.19 2008 Polysilicon Producer Market Shares ............................................................ 5-27

5.20 2008 Hemlock Estimate of Polysilicon Producer Market Shares .......................... 5-28

5.21 Hemlock Semiconductor Ownership ..................................................................... 5-29

5.22 2008 Hemlock Estimate of 2014 Polysilicon Producer Capacity .......................... 5-31

5.23 Hemlock Forecast of Solar Polysilicon Demand ................................................... 5-34

5.24 Log Scale Hemlock Forecast of Solar Polysilicon Demand .................................. 5-35

© SRI Consulting xviii PEP Report 272


5.25 Hemlock Forecast of Solar Polysilicon Demand ................................................... 5-35

5.26 Hemlock Forecast of Discounted Polysilicon Demand ......................................... 5-36

5.27 Centrotherm Forecast of Discounted Polysilicon Demand ................................... 5-37

5.28 Calisolar Polysilicon Supply/Demand Forecast..................................................... 5-38

5.29 iSupply Polysilicon Price Forecast ........................................................................ 5-39

5.30 Polysilicon Price Assessment................................................................................ 5-40

5.31 Solar vs. Semiconductor Grade Polysilicon Prices ............................................... 5-40

6.1 Silicon Vapor Pressure.......................................................................................... 6-2

6.2 Monocrystalline Silicon.......................................................................................... 6-4

6.3 Polysilicon Processing........................................................................................... 6-5

6.4 Overall Gas Plant Process Schematic .................................................................. 6-11

6.5 Gas Plant Block Flow Diagram.............................................................................. 6-12

6.6 Hemlock Polysilicon Production from Metallurgical Grade Silicon........................ 6-14

6.7 Union Carbide Polysilicon Production from Metallurgical Grade Silicon............... 6-15

6.8 SRIC Generic Polysilicon Production from Metallurgical Grade Silicon ............... 6-17

6.9 Czochralski Schematic for Monocrystalline Silicon............................................... 6-22

6.10 Float Zone Method Schematic .............................................................................. 6-23

7.1 US PEP Cost Index ............................................................................................... 7-16

8.1 Siemens Reactor Schematic Drawing................................................................... 8-2

8.2 Filament Rods in a Siemens Reactor.................................................................... 8-3

8.3 Closed Loop Siemens Reactor Process ............................................................... 8-6

8.4 Deposition Rate as a Function of Temperature and Pressure.............................. 8-7

8.5 Deposition Rate as Function of Energy Consumption .......................................... 8-8

8.6 Representative Siemens Reactor Internals........................................................... 8-11

8.7 Siemens Reactor Block Flow Diagram.................................................................. 8-16

8.8 Polysilicon via Siemens Reactor Process Flow Diagram .......................................................................................... C-3

9.1 DuPont US Patent 3012861 for Fluidized Bed Reactor ........................................ 9-1

© SRI Consulting xix PEP Report 272


9.2 Basic DuPont US Patent 3012862 for Fluidized Bed Reactor .............................. 9-2

9.3 Closed Loop Fluidized Bed Reactor Schematic.................................................... 9-6

9.4 Solid Grain Flow in Fluidized Bed Reactor............................................................ 9-7

9.5 Zones within Fluidized Bed Reactor...................................................................... 9-8

9.6 Power Consumption in Silicon Deposition Reactors............................................. 9-10

9.7 Fluidized Bed Reactor Process Schematic From USP 5139762.......................... 9-12

9.8 Fluidized Bed Reactor Internals from USP 5139762 ............................................ 9-13

9.9 Liquid Ring Vacuum Ring...................................................................................... 9-14

9.10 Polysilicon Seed Particle Production..................................................................... 9-15

9.11 Temperature Profile in Fluidized Bed Reactor ...................................................... 9-16

9.12 Wacker's Microwave Fluidized Bed Reactor ......................................................... 9-18

9.13 Improved Wacker Fluidized Bed Reactor.............................................................. 9-19

9.14 Series Siemens/Fluidized Bed Reactor Configuration .......................................... 9-21

9.15 Fluidized Bed Reactor Block Flow Diagram.......................................................... 9-22

9.16 Polysilicon via Fluidized Bed Reactors Process Flow Diagram .......................................................................................... C-5

9.17 Polysilicon via Fluidized Bed Reactors Process Flow Diagram .......................................................................................... C-7

9.18 Dry Screw Vacuum Pumps ................................................................................... 9-28

10.1 Silicon Purification Processes ............................................................................... 10-6

10.2 Contaminant Concentration from Silicon Melt Phase............................................ 10-12

10.3 Calisolar Patent Application for Crucible Directional Crystallization ..................... 10-15

10.4 Calisolar Patent Application for Wafer Heat Treatment & Gettering ..................... 10-16

10.5 Calisolar Patent Application for Oval Crucible and Directional Solidification........ 10-16

10.6 Impurity Build-up in Crucible Melt.......................................................................... 10-19

10.7 Patent for Continuous Silicon Furnace Processing............................................... 10-23

10.8 Sumitomo / Mitsubishi Patent for Continuous Silicon Furnace Processing .......... 10-24

10.9 Upgraded Metallurgical Grade Silicon Brick Process Flow Diagram .......................................................................................... C-9

© SRI Consulting xx PEP Report 272

ILLUSTRATIONS (Concluded)

11.1 Linx Consulting Forecast of Thin-Film Market Share ............................................ 11-1

11.2 'Solar Stocks Commentary' Thin Film PV Market Shares 2005............................ 11-2

12.1 Multi-Junction Solar Cell........................................................................................ 12-2

12.2 String Ribbon Puller Schematic............................................................................. 12-4

12.3 Solarfun Full Square Solar Wafer.......................................................................... 12-5

12.4 Fullerene Based Organic Solar Cell ...................................................................... 12-6

© SRI Consulting xxi PEP Report 272

TABLES

1.1 Silicon Purity Requirements for the PV Industry ................................................... 1-7

1.2 Market Share for Silicon Products......................................................................... 1-9

1.3 Value of Properties made from Silicon .................................................................. 1-10

1.4 Forms of Silicon Based Solar Wafers.................................................................... 1-11

1.5 Major Public Photovoltaic Companies Listed on US Stock Exchanges................ 1-15

1.6 Major German (DAX) Listed Public Companies in Photovoltaic Business ........... 1-16

3.1 Industry Design and Engineering Safety Standards ............................................. 3-2

3.2 SEMI Design and Engineering Safety Standards ................................................. 3-3

3.3 Factory Mutual Design and Engineering Safety Standards .................................. 3-4

3.4 Process Safety References................................................................................... 3-4

3.5 PV Industry Significant Safety Incidents................................................................ 3-6

3.6 Company (Syncrude) Published 2006 Safety Performance ................................. 3-9

3.7 Information Inputs Necessary to Conduct a HAZOP Review................................ 3-10

3.8 Combustion Potential of Dust Materials ................................................................ 3-21

3.9 Compressed Gas Association Safety Standards for Hydrogen ............................ 3-22

3.10 Preliminary HAZOP Issue Summary ..................................................................... 3-23

4.1 Photovoltaic Industry Associations........................................................................ 4-23

4.2 Hazardous Chemicals Used in PV Product Chain ................................................ 4-25

4.3 US DOE Cell and Module Shipments by Type...................................................... 4-28

4.4 PV Technology Comparison.................................................................................. 4-30

5.1 US DOE Major Contracts to Fluidized Bed Reactor Development ....................... 5-2

5.2 Principal Metallurgical Grade Silicon Purity .......................................................... 5-7

5.3 IMF Historic and Projected GDP Growth .............................................................. 5-12

5.4 Photovoltaic Industry Global Capacity................................................................... 5-14

5.5 Photovoltaic Industry Targets of Chinese Government......................................... 5-16

5.6 China Ordos Photovoltaic Project ......................................................................... 5-17

5.7 EPIA Forecast of 2020 Photovoltaic Installed Capacity ........................................ 5-19

© SRI Consulting xxii PEP Report 272

TABLES (Continued)

5.8 SRIC Segmentation of Regional Photovoltaic Capacity........................................ 5-20

5.9 Frost & Sullivan Listing of Major Photovoltaic Competitors................................... 5-23

5.10 Capacity Announcements of Major Photovoltaic Competitors .............................. 5-24

5.11 Major Photovoltaic Cost Components ................................................................... 5-25

5.12 Major Photovoltaic Toolmakers ............................................................................. 5-26

5.13 Major Polysilicon Producers .................................................................................. 5-27

5.14 Polysilicon Capacity Announcements ................................................................... 5-30

5.15 Merrill-Lynch Assessment of Polysilicon Producer Capacity ................................ 5-32

5.16 SRIC Assessment of Polysilicon Producer Capacity ............................................ 5-33

5.17 Hemlock Assessment of Polysilicon Demand Growth .......................................... 5-33

5.18 Semi Quarterly 2008 Polysilicon Shipment Data .................................................. 5-34

5.19 SRIC Forecast of Polysilicon Demand .................................................................. 5-37

5.20 2009 Spot Polysilicon Prices in China................................................................... 5-41

6.1 Silicon Physical Properties .................................................................................... 6-1

6.2 Silicon Product Specifications ............................................................................... 6-3

6.3 Physical Properties of Silicon Containing Gases .................................................. 6-8

6.4 Silicon Hydrochlorination Reaction Selectivity ...................................................... 6-9

6.5 Gas Plant Generic Process Parameters ............................................................... 6-13

7.1 Polysilicon Contaminant Specifications................................................................. 7-5

7.2 2008 Retail Power Costs....................................................................................... 7-6

7.3 Low Electricity Cost Regions................................................................................. 7-7

7.4 Normal SRIC Offsite Cost Components ................................................................ 7-8

7.5 Relevant Standards Setting Organizations ........................................................... 7-11

7.6 SEMI Standards Committees ................................................................................ 7-12

7.7 Relevant SEMI Polysilicon Grouping Standards ................................................... 7-12

7.8 Temperature Design Conditions............................................................................ 7-13

7.9 Construction Cost Location Factors ...................................................................... 7-14

© SRI Consulting xxiii PEP Report 272

TABLES (Continued)

7.10 US PEP Cost Index ............................................................................................... 7-17

7.11 Project Cost Factors .............................................................................................. 7-19

8.1 Standardized Solar Wafer Sizes ........................................................................... 8-3

8.2 Hairpin Filament Dimensions Offered by Kayex Filaments................................... 8-4

8.3 Established Companies using Siemens Reactors ................................................ 8-9

8.4 Commercial Vendors of Siemens Reactors .......................................................... 8-9

8.5 Commercial Vendor Siemens Reactors ................................................................ 8-10

8.6 Clean Room Standards ......................................................................................... 8-13

8.7 Siemens Reactor Project Design Basis ................................................................ 8-15

8.8 Siemens Reactor Material Balance....................................................................... 8-18

8.9 Siemens Process Equipment List.......................................................................... 8-19

8.10 Siemens Process Itemized Capital Cost ............................................................... 8-20

8.11 Siemens Process Total Capital Investment .......................................................... 8-21

8.12 Siemens Process Production Cost Elements........................................................ 8-22

8.13 Siemens Process Variable Cost Assessment ....................................................... 8-23

8.14 Siemens Process Total Cost Assessment ............................................................ 8-24

8.15 Siemens Process Cash Cost Profitability.............................................................. 8-25

8.16 Thomas Weisel Partners Estimate of Polysilicon Costs ....................................... 8-26

9.1 Union Carbide Fluidized Bed Reactor Conditions................................................. 9-3

9.2 Representative US Patents for Fluidized Bed Deposition of Polysilicon .............. 9-5

9.3 Project Process Design Conditions....................................................................... 9-23

9.4 Fluidized Bed Reaction Material Balance ............................................................. 9-26

9.5 Fluidized Bed Reaction Equipment List................................................................. 9-29

9.6 Fluidized Bed Reaction Itemized Capital Cost ...................................................... 9-30

9.7 Fluidized Bed Reactor Cost Estimate.................................................................... 9-31

9.8 Fluidized Bed Production Cost Elements.............................................................. 9-32

9.9 Fluidized Bed Process Variable Cost Assessment ............................................... 9-33

© SRI Consulting xxiv PEP Report 272

TABLES (Concluded)

9.10 Fluidized Bed Process Total Cost Assessment .................................................... 9-34

9.11 Fluidized Bed Cash Cost Profitability .................................................................... 9-35

9.12 Production Cost Comparison (Siemens vs. Fluidized Bed) .................................. 9-35

10.1 Performance Comparison of Solar Cells Made from UMG-Si............................... 10-3

10.2 Solar Cell Efficiency as Function of Feedstock ..................................................... 10-4

10.3 Economics Benefits of UMG-Si Technology ......................................................... 10-4

10.4 Silicon Metal Grade Purity ..................................................................................... 10-5

10.5 Companies Involved in UMG-Si ............................................................................ 10-6

10.6 Major DSS Furnace Vendors ................................................................................ 10-7

10.7 Timminco Major US Patent Applications ............................................................... 10-8

10.8 Features of ALD DSS Furnaces............................................................................ 10-9

10.9 Calisolar Patents for Upgrade Metallurgical Grade Silicon ................................... 10-14

10.10 UMG-Si Material Balance...................................................................................... 10-27

10.11 UMG-Si Equipment List ......................................................................................... 10-28

10.12 UMG-Si Itemized Capital Cost .............................................................................. 10-29

10.13 UMG-Si Cost Estimate .......................................................................................... 10-30

10.14 Upgraded Metallurgical Grade Silicon Production Cost Elements........................ 10-31

10.15 Upgraded Metallurgical Grade Silicon Variable Cost Assessment ....................... 10-32

10.16 Upgrade Metallurgical Silicon Total Cost Assessment ......................................... 10-33

10.17 Upgraded Metallurgical Grade Silicon Cash Cost Profitability .............................. 10-34

10.18 Production Cost Comparison ................................................................................ 10-34

Documents

Polysilicon for Solar Wafers - Markit · POLYSILICON FOR SOLAR WAFERS Report No. 272 by Anthony Pavone December 2009 Menlo Park, California 94025 Process Economics Program A private