Process and RTP equipment design for Cu(In,Ga)Se2 layer formation using in-situ XRD techniques

Summary form only given. Centrotherm photovoltaics AG is one of the first turn-key supplier of fabrication lines for the production of whole Cu(In,Ga)Se<;sub>2<;/sub> (CIGS)-based thin-film modules of a size of ~1.5m². The core-technologies for CIGS-absorber layer formation were developed in centrotherms research & development center in Blaubeuren (Germany) and represent a completely new approach, not reported in literature before. While the utilized sputter deposition of the Molybdenum back-contact and the Cu(Ga,In) metallic precursor stack is a well-proved and easy scalable deposition technique, the newly introduced techniques of an atmospheric Selenium-deposition and subsequent repid thermal processing in an atmospheric through-type furnace offer new perspectives for the economical success of CIGS-thin-film photovoltaics, since they overcome the scaling problems and long process times commonly associated with conventional PVD and vacuum-based techniques. Since these long process times are not compatible with the growing demand for cheaper photovoltaics, centrotherms CIGS-formation process was designed with a 60s cycle-time using rapid thermal processing techniques. For these unrivalled short process times, it is crucial to generate a profound knowledge about the phase formation and interdiffusion processes going on and, even more important, about the essential parameters determining the solid state reactions to ensure a complete process control. Against this background, centrotherm photovoltaics AG has set up, an unique laboratory-scale in-situ X-Ray diffraction (XRD) system allowing for the real-time investigation of phase formation processes. This device is build around a small rapid thermal processing (RTP) furnace, mapping centrotherms atmospheric ClGS-formation process to a laboratory scale. The contribution will report the systematic progress made in CIGSe RTP process design using this unique tool. The profound understanding - - gained trough such experimentation techniques flows directly into the design in state of the art high throughput manufacturing equipment.