HelioVolt Corporation: The Future of Photovoltaic Power

1. HelioVolt Corporation:The Future of Photovoltaic Power B.J. StanberyHelioVolt Corporation 8201 E. Riverside Dr., Suite 600Austin, TX 78744 Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

2. Cost Durability Efficiency HelioVolt Mission • To develop and commercialize a new generation of efficient, safe, reliable, and attractive thin-film photovoltaic solar power products that are the first to enable energy production at cost parity with conventional sources of electricity. • Lowest cost thin film circuits, less than one fourth that of silicon PV and one tenth that of current Building Integrated PV (“BIPV”) products • Warranted Lifetime of at least 20 years for first products • Comparable conversion efficiencies to multicrystalline silicon Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

3. Solar Power Learning Curve • Plateau in direct manufacturing costs • Data source Luuk Beurskens, ECN Policy Studies, PHOTEX’03 Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

4. Lifetime Required for 10¢/kW·h Energy at Various Module Costs Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

5. Solar Power Yesterday • Silicon Photovoltaic (PV) modules for retrofit • PV module sales $5.5B (2005) • PV market 30+% CAGR since ‘97, +40% 2005 • Sales <½% total annual global CapEx for electrical power generation • Current market limited by supply, even at price of • $4/Wp modules + $3 installation = $7/Wp Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

6. Over $1 in silicon materials cost dominates COGS Data source Prog.Photovolt.Res.Appl. 5, 309-315(1997) Silicon Module Limitations $1.78/Wp projected lowest costfor crystalline Si PV modules Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

7. Semiconductor Cost Reduction Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

8. Solar Power Tomorrow • Power Buildings will become multi-$T market • PV as an integrated electronic component • Efficient, durable thin-film solar cells incorporated into traditional building materials • Current products unsuitable for this market Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

9. Electrical Demand met by PV Power Buildings Market • Huge latent demand • USA potential:$150B/yr • 60% share • Multiple segments • Architectural glass • Windows & skylights • Roofing Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

10. Precursor 1 Reactive Transfer Printing Printing Plate Precursor 2 Stage 1: Precursors’ Deposition Substrate Printing Plate Mechanical (& Electrostatic) Pressure Heat Stage 2: Rapid Thermal Processing and Separation Product Layer Substrate Micro-Reactor Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

11. CIGS PV Device Semiconductor: Copper Indium Gallium Diselenide • Highest efficiency single-junction thin-film PV semiconductor material • 19.5% conversion efficiency (NREL) • Unique material properties derive from spontaneous nanostructuring • Inherently stable under normal operating conditions • Second generation photovoltaic semiconductor material Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

12. RTP Implementation: FASST ™ CIGS Semiconductor Synthesis • Field-Assisted Simultaneous Synthesis and Transfer • Second generation CIGS manufacturing technology • Advantages • Rapid processing • Vastly reduced thermal budget • Confinement of volatile selenium • Electrostatic field effects on ionic constituent transport during synthesis Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

13. Rapid Thermal Processor Electrostatic Chuck Printing Plate Printing Plate Release Layer Printing Plate Precursor 2 Release Layer Precursor 2 Release Layer Precursor 1 Metal Contact Layer Precursor 1 Substrate Metal Contact Layer Substrate emitter CIGS CIGS Metal Contact Layer Metal Contact Layer Substrate Substrate Completed Device FASST ™ Process Sequence Flash Heating Recoat Printing Plate Device Processing Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

14. First Factory Production Flow Metal Pattern (P1) Glass Clean 1. Front End Metal Deposition PrecursorDeposition 3. Buffer BufferDeposition FASST ™ Synthesis 2. CIGS Synthesis Absorber Pattern (P2) TCODeposition TCO Pattern (P3) 4. Device Processing Product Packaging Test & Ship 5. Back End Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

15. CIGS Thin-Film Products • CIGS is an alloy of Copper, Indium, Gallium and Selenium • Monolithic integration forms circuits without high wafer assembly costs • CIGS is one of three known intrinsically stable PV materials (with Silicon and Gallium Arsenide) • Instrinsic stability required for long lived robust products • More efficient absorber of light than any other known semiconductor • Requires 1/100th of the material compared to silicon for comparable light absorption Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

16. Product Value Proposition Revolutionary FASSTTM Manufacturing Process CIGS Thin-Film Technology HelioVolt Thin-Film PVICs • Highest performance; most versatile & durable • PVIC platform avoids costly inter-cell wiring & bypass components • Proven semiconductor CIGS (Copper Indium Gallium Selenide) • Lowest Cost Thin Film Devices • Less than 1/4th the cost of silicon PV module • Integrated systems for Power Buildings less than1/10th cost of current technologies • Lower cost electricity than effective current retail electricity prices in five years • Wide Range of Applications for both rigid and flexible PVIC platform products • Traditional PV modules • Building Integrated PV (BIPV) Systems Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

17. Reactive Transfer Printing (RTP) • Combines features of • Rapid Thermal Annealing, and (optionally) • Anodic Wafer Bonding • electrostatic fields effects • Advantages • Rapid processing • Eliminates pre-reaction • Independent pre-heating of precursors • Confinement of volatile species • Independent precursor deposition optimization Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

18. Rapid Thermal Annealing (RTA) • RTA is a non-equilibrium thermal processing method widely used in semiconductor device manufacturing • Often used to provide activation energy whilst minimizing concomitant diffusion • Employed for formation and annealing of gate dielectric layers in FET’s • Used for reactive formation of electrical contacts by thermal silicidation of silicon/metal interfaces Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

19. Metal Selenization Coevaporation HelioVoltFASST™ CIGS Film Process Time • Rapid processing delivers high capital efficiency Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

20. Thermal Budget Comparison • One to three orders of magnitude reduction in thermal budget Figure of Merit (FOM) • Highest average processing temperature Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

21. Anodic Wafer Bonding (AWB) • AWB is widely used for MEMS manufacture • Employs electrostatic fields to bond alkali glass to semiconductors or metals with lower temperature and pressure than fusion bonding • High voltage across the wafer/glass stack repels mobile ions in the glass, inducing a space-charge and creating strong electrostatic compression, pulling them into intimate contact on an atomic scale. Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

22. Electrostatic Compression • HelioVolt’s FASST™ CIGS process utilizes both mechanical and electrostatic compression • Length scale is much smaller than conventional AWB Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

23. CIGS Precursor Deposition Methods • Low-temperature vacuum deposition • Provides increased throughput compared to conventional high-temperature CIGS synthesis by co-deposition or selenization • Non-vacuum liquid precursor deposition • HelioVolt/NREL Cooperative Research & Development Agreement (CRADA) • Goal: development of non-vacuum nanomaterial-based precursor deposition processes • Synthesis of CIGS demonstrated using FASST™ processing • Details to be presented by Jennifer Nekuda at the Fall 2007 MRS meeting in Boston later this month Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

24. Recrystallization of Nanoscale Granular Precursor Films • FASST™ CIGS cross-section Precursor Film Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

25. Composition Fluctuations and Carrier Transport in CIGS PV Absorbers • Peculiar semiconductor behavior: Copper Indium Gallium Selenide (CIGS) PV devices insensitive to extended defects and ±5% atomic composition variations of its metallic constituents • Selenium deficiency results in poor devices • Observations • CIGS PV devices are always copper deficient compared to a-CuInSe2 • Compositions lie in the equilibrium a+b 2-phase domain Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

26. Composition Fluctuations and Carrier Transport in CIGS PV Absorbers • Experimental results* HAADF-TEM & nano-EDS • 5-10 nm characteristic domain size (2-D) • Pearson product-moment statistical correlation between the two variables Cu/(In+Ga) and Ga/(In+Ga) is 0.72 (null P=0.3% ) *Applied Physics Letters, 87, 2005, 121904 Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

27. Reactive Transfer Printing for Film Synthesis • RTP is an advanced printing method for making films and coatings. It offers • Low thermal budget • Confinement of volatile reaction components • Electrostatic modification of ionic transport • FASST™ implementation of RTP is a processing method with demonstrated capabilities to • Utilize nano-particle based precursors for high-quality CIGS synthesis • Modify nanodomain formation during CIGS synthesis Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation

28. HelioVolt Corporation:The Future of Photovoltaic Power B.J. StanberyHelioVolt Corporation 8201 E. Riverside Dr., Suite 600Austin, TX 78744 Energy Technology & Policy B.J. Stanbery, HelioVolt Corporation