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)Se2 (CIGS)-based thin-film modules of a size of ~1.5m 2 . 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.