Study of MIS silicon solar cells by ESCA and AES

ESCA and AES were combined with ion sputtering to study the compositional structure of MIS polycrystalline silicon solar cells. Oxygen was introduced into the metallic chromium layer of the cell to redduce the work function of the chromium and thus to increase the open-circuit voltage of the cell. A Cr₂O₃ layer formed during deposition of the metallic Cr layer was observed by studying the ESCA-sputtering profiles. Chromium carbide was detected as contamination in the Cr layer. This probably would cause an increase in series resistance. Samples with different oxide thickness (20 and 200 Å of SiO₂ layers) were studied. Pure metallic Cr was found to diffuse through the SiO₂ layer and about 30 Å into the Si film. These results are useful in suggesting a design to increase the stability of Cr-MIS solar cells.