Purification of silicon thin films containing nitrogen and oxygen impurities using aluminum-induced crystallization

We have presented a method for eliminating impurities in low-purity Si films using aluminum-induced crystallization (AIC). When AIC is applied to a silicon (Si) film containing oxygen (O) and nitrogen (N) atoms, polycrystalline Si grains are grown and they are covered with an Al layer. By Auger electron spectroscopy (AES) measurement, we found that both concentrations of N and O atoms were lower than the AES detection limit (1 at%) in the polycrystalline Si grains, and N and O atoms were condensed in the surface Al layer. These results indicate that AIC can be one of the methods for obtaining high-purity Si grains from low-purity Si films at relatively low temperature.