Preoxidation cleaning optimization for crystalline silicon [solar cell manufacture]

A series of controlled experiments has been performed to evaluate the effect of various chemical surface treatments on the recombination lifetime of crystalline silicon solar cell wafers subjected to high temperature dry oxidation. From this series of experiments, a relatively simple, yet effective, cleaning sequence is deduced. Also evaluated is the effect of different chemical damage-removal etches for improving the recombination lifetime and surface smoothness of mechanically lapped wafers. The methodology used, the experimental results obtained, and the authors´ experience using this process on a continuing basis over a period of many months are presented