Deep level effects in silicon and germanium after plasma hydrogenation
Deep level electron and hole trapping states are observed in n-and p-type silicon after plasma hydrogenation at 250 - 300°C. These defect states are not observed after exposure to a helium plasma. In contrast to these results, no hydrogen or helium plasma-induced levels are seen in n-or p-type germanium after similar heat treatment of up to 600°C. However, hydrogenation of p-type germanium at 600°C significantly enhances the solubility of the rapidly diffusing impurity copper, compared to untreated material. Reproducing the experiments using a helium plasma does not affect the copper solubility. A simple model which accounts for the experimental results is proposed.