c-Si surface passivation for photovoltaic applications by means of antireflective amorphous silicon carbide layers

Surface passivation of p-type silicon wafers was performed by amorphous silicon carbide films (SiC_x) deposited by plasma enhanced chemical vapor deposition (PECVD). Stacks of two different SiC_x layers were applied. The inner layer was rich in silicon and offered good passivation properties. The outer layer was a carbon rich, antireflective coating. Anneals in forming gas were performed to improve surface passivation. Simulation of lifetime measurements indicated the nature of the passivating mechanism. Finally, optical constants were determined by ellipsometry measurements.