New technologies for CIGS photovoltaics

This paper describes a new process for forming Cu(In,Ga)Se 2 (CIGS) by vacuum processing. It is termed the hybrid process, and it involves thermal delivery of In, Ga, and Se and sputtering 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, and interconnect resistance. The paper also describes the application of a new sputtering process for compound film formation to the area of CIGS processing. This process is termed reactive environment sputtering, and is based on a hollow cathode discharge. The process is applied to the formation of transparent conducting oxides (TCO) such as ZnO:Al, ZnO:B, In 2O 3:Mo (IMO) and In 2O 3:Ti (ITiO), and to their use as window layers for CIGS devices.