Mechanical wafer stability enhancements and texturing effects of remote downstream plasma etching

The mechanical stability of wafer material strongly depends on the solar cell processing steps. In our previous investigations, the largest improvement in wafer stability was achieved by appropriate saw damage removal. The work presented in this paper is concerned with investigations of different saw damage removal techniques that can improve the mechanical wafer stability at the beginning of the solar cell process. We investigated two different stress reducing plasma etching recipes that turned out to provide the same stability improvements as achieved with alkaline etching. Additionally, the plasma etching technique gives a random surface texturing, which results in a lower cell reflectivity, increasing the short circuit current. Experiments were done to find an optimum parameter set of this plasma texturing process to that maintained the open circuit voltages and fill factors achieved with standard alkaline etching.