Oxygen-related vibrational modes produced in Czochralski silicon by hydrogen plasma exposure

Abstract

Plasma hydrogenation of Czochralski Si has been performed to investigate the introduction of Si–O stretch modes and their correlation with thermal donor formation. Plasma hydrogenation at 275 °C introduces a well-resolved vibrational absorption band at 1005 cm−1, while absorption due to electronic excitations for thermal donors remains weak. We attribute this band to a Si–O precursor center for thermal donor formation, and suggest it is the oxygen dimer center discussed in other studies of oxygen in Si. Vibrational modes introduced at 990 and 1000 cm−1 during post-hydrogenation furnace annealing at 400 °C correlate with thermal donors TD2 and TD3, respectively. Stretch frequencies for Si–O in thermal donor centers are compared to those for oxygen aggregates in oxygen-implanted and electron-irradiated Si.