Integrated Electrical and Optical Characterization of Large Area Thin Film Photovoltaic Materials

In thin film photovoltaic manufacturing, a number of different technologies are now used on an industrial scale: silicon-based thin films, CIS/CIGS-based thin films, CdTe-based films and other, more exotic materials and structures. Both during research and production control, there is a need for suitable characterization methods which can be applied directly to the panels in production. In this paper we present a range of advanced electrical and optical metrology techniques suitable for such thin film characterization. These measurements utilize a number of non-contact, non-destructive probes to determine material properties, and can be configured in a single flexible platform, to handle the large area substrates used in thin film production. We also present significant improvements achieved in the spectrally resolved haze and transmission measurements, where the improvement is the creation of an optical setup with a suitable integration sphere that enables these measurements without the usual need to measure a reference sample before the actual sample qualification, thus maintaining the advantages of an integrating sphere but reducing usual measurement time.