Transverse probe optical lifetime measurement as a tool for in-line characterization of the fabrication process of a silicon solar cell

In this paper an all-optical measurement procedure for the characterization of minority carrier recombination lifetime and surface recombination velocity is presented as a reliable tool to monitor the fabrication process of a standard crystalline silicon solar cell. In the methodology presented here, there are no stringent requirements concerning the state of wafer surface. The IMEC (Interuniversity Microelectronics Centre, Leuven, Belgium) fabrication process is taken as an example of the capability of this method to monitor the whole process from the silicon wafer to the finished cell. It is shown that the cell process does not degrade the bulk recombination lifetime and that the effect of the external surfaces is effectively screened.