This document discusses HelioVolt Corporation's proprietary reactive transfer process for manufacturing copper indium gallium selenide (CIGS) photovoltaic modules. The process combines rapid thermal processing and anodic wafer bonding to synthesize high-quality CIGS films from precursor layers in only 6 minutes. CIGS cells fabricated with this process have achieved 14% efficiency. HelioVolt has scaled this process to produce CIGS modules on a 20 MW pilot line, with 12% module efficiency demonstrated. The company aims to further scale production to multi-100MW factories to commercially produce CIGS modules using this low-cost, scalable reactive transfer method.

1. © 2010 HelioVolt Corporation
Copper Indium Gallium Selenide Photovoltaic
Modules Manufactured by Reactive Transfer
Dingyuan Lu, Baosheng Sang, Yuepeng Deng,
Billy J. Stanbery, and Louay Eldada
HelioVolt Corporation
© 2010 HelioVolt Corporation

2. © 2010 HelioVolt Corporation
CIGS Photovoltaic & HelioVolt
CIGS is among the most promising PV technologies for
Cost-effective power generation resulting from low material consumption
and large truly monolithically integrated modules at any size
Highest efficiency capability of non-concentrated single-junction TF PV
technologies (a-Si, CdTe, CIGS, DSSC, OPV)
HelioVolt Corporation:
Developed a cost effective CIGS process – Field-Assisted Simultaneous
Synthesis and Transfer (FASST®)
Scaled up initially on a 20 MW production line using six sigma
methodology
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3. © 2010 HelioVolt Corporation
CIGS by FASST® Reactive Transfer Process
Combines features of:
 Rapid Thermal Processing
 Anodic Wafer Bonding
Advantages:
 Rapid processing
 Low thermal budget
 Confinement of volatile Se
 High material utilization
 Electrostatic field effects on ionic
constituent transport during
synthesis
 Having two precursors allows
independent optimization of:
 Composition
 Structure
 Deposition method
 Processing conditions
Constantly evolving as
process is scaled up
Two Stages
 Precursor deposition of multinary Selenides
 Rapid thermal processing & separation
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4. © 2010 HelioVolt Corporation
CIGS Film by Reactive Transfer in 6 minutes
with PVD-based Precursors
CIGS
Mo
XRD
 Chalcopyrite CIGS (& Mo)
 (220/204) preferred orientation,
helps junction formation,
improves cell performance
SIMS Depth Profile
 Uniform elemental distribution
complete reaction of precursors
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5. © 2010 HelioVolt Corporation
SEM Images for CIGS by Reactive Transfer
Large grains
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Faceted CIGS
surface

6. © 2010 HelioVolt Corporation
Uniform High-Quality CIGS Polycrystalline Films
Deliver 14% Cell Efficiency
Area = 0.66 cm2
Voc = 630.5 mV
Jsc = 30.9 mA/cm2
FF = 71.8 %
Eff = 14.0 %
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7. © 2010 HelioVolt Corporation
HelioVolt’s CIGS Module Process Flow & Technology
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Glass In Module Out
= 2.5 hrs
PVIC
Sputtered Mo
Cu-In-Ga-Se precursor films
CIGS by reactive transfer
Buffer layers
Sputtered TCO
Bus bars and tabs
Edge sealant application
Lamination
Quality control testing
Laser patterning 1
Mechanical patterning 2
Mechanical patterning 3

8. © 2010 HelioVolt Corporation
Modeling for Device/Module Design
 HelioVolt CIGS device/module design further improved by various
modeling methods, e.g. 2-D circuit design, device physics modeling,
and thermodynamics modeling
• Circuit model
Module
Sub-cell
Segment Sub-cells network
TCO network
Mo network
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63.5
64
64.5
65
65.5
66
75
76
77
78
79
80
8 10 12 14 16 18 20 22
ModuleFF(%)
ModulePowerOutput(W) TCO Sheet Resistance (Ω/□)
Power
FF (%)

9. © 2010 HelioVolt Corporation
Uniform High-Quality CIGS Polycrystalline Films
Deliver 12% Module Efficiency
Voc = 35.85 V
Isc = 0.36 A
Fill Factor = 64.0%
Efficiency = 12.03%
Spire 4600SLP Sun Simulator
Device ID: #051509G1-4 Irradiance: 1000.0 W/m2
Vmax = 27.30 V
Imax = 0.30 A
Pmax = 8.19 W
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Analysis performed on early module prototype

10. © 2010 HelioVolt Corporation
Scale-up Evolution
Cell: 1x0.66 = 0.66 cm2
G1 Module: 30x30 = 900 cm2
G2 Module: 120x60 = 7200cm2
Critical uniformity control in Gen 2
• Precursor composition and thickness
• Thermal uniformity, especially at peak
reaction temperature
Going from cell to Gen 1 module
Scalability Proof
DONE Going from Gen 1 to Gen 2 Module
Commercial Production Size
NOW
8x scale-up1364x scale-up
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11. © 2010 HelioVolt Corporation
CIGS Module Product Specifications
• HelioVolt CIGS Photovoltaic Module
– Commercial, residential, utility applications
– BIPV products in development
• Construction: Glass-glass laminate
• Dimensions: 600 mm x 1210 mm x 7 mm
• Weight: 12 kg
• Power: 75 – 85 W
• Voltage at Max Power: 48 – 67 V
• Certifications: UL, IEC
• Warranty: 25 years
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12. © 2010 HelioVolt Corporation
HelioVolt PV Module Production Line
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Moly Deposition Precursor Deposition Load CIGS Processor Load
CIGS Processor Unload Buffer Load
PVIC Lamination Junction Box Attach Final Eff. Test
Final PVIC Pattern Step

13. © 2010 HelioVolt Corporation
HelioVolt Modules Installed for
Rooftop Test
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14. © 2010 HelioVolt Corporation
Summary
 CIGS films printed with HelioVolt’s proprietary reactive
transfer process have high quality grain structure and
produce high performance devices
 CIGS modules were fabricated with reactive transfer and
achieved 12% module efficiency
 The HelioVolt reactive transfer process has been scaled
up on a 20MW pilot production line, with multi-100MW
factory in planning
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15. © 2010 HelioVolt Corporation
Thank You!
www.heliovolt.com
© 2010 HelioVolt Corporation