Photovoltaic Manufacturing Cost and Throughput Improvements for Thin-Film CIGS-Based Modules: Phase I Technical Report, July 1998 - July 1999

The primary objectives of the Global Solar Energy (GSE) Photovoltaic Manufacturing Technology (PVMaT) subcontract are directed toward reducing cost and expanding the production rate of thin-film CuInGaSe2 (CIGS)-based PV modules on flexible substrates. Improvements will be implemented in monolithic integration, CIGS deposition, contact deposition, and in-situ CIGS control and monitoring. In Phase1, GSE has successfully attacked many of the highest risk aspects of each task. All-laser, selective scribing processes for CIGS have been developed, and many end-of-contract goals for scribing speed have been exceeded in the first year. High-speed ink-jet deposition of insulating material in the scribes now appears to be a viable technique, again exceeding some end-of-contract goals in thefirst year. Absorber deposition of CIGS was reduced corresponding to throughput speeds of up to 24-in./min, also exceeding an end-of-contract goal. Alternate back-contact materials have been identified that show potential as candidates for replacement of higher-cost molybdenum, and a novel, real-time monitoring technique (parallel-detector spectroscopic ellipsometry) has shown remarkablesensitivity to relevant properties of the CIGS absorber layer for use as a diagnostic tool. Currently, one of the bilayers has been baselined by GSE for flexible CIGS on polymeric substrates. Resultant back-contacts meet sheet-resistance goals and exhibit much less intrinsic stress than Mo. CIGS has been deposited, and resultant devices are comparable in performance to pure Mo back-contacts.Debris in the chamber has been substantially reduced, allowing longer roll-length between system cleaning.