New technologies for CIGS photovoltaics

This paper describes a new process for forming Cu(In,Ga)Se2 (CIGS) by vacuum processing. It is termedthe hybrid process, andit involves thermal delivery of In, Ga, and Se andsputtering of Cu. The optimization of the process is described, followed by its successful application to large area processing of CIGS devices and modules. Other processing issues in module formation are also discussed and analyzed, including deposition of the buffer and window layers, andinterconnect resistance. The paper also describes the application of a new sputtering process for compoundfilm formation to the area of CIGS processing. This process is termedreactive environment sputtering, and is basedon a hollow cathode discharge. The process is applied to the formation of transparent conducting oxides (TCO) such as ZnO:Al, ZnO:B, In2O3:Mo (IMO) andIn 2O3:Ti (ITiO), and to their use as window layers for CIGS devices. 2004 Elsevier Ltd. All rights reserved