Stability Studies on A-Si:H Films

Abstract

ABSTRACTWe report on kinetics of photo-induced degradation in a-Si:H films and devices. We find that in device-quality films, the degradation kinetics do not follow either the time or the intensity behavior predicted by the bondbreaking model. Instead, there is a strong tendency towards saturation, as predicted by Redfield's equilibration model. We also find that increased SiH2 bonding in the film leads to increased degradation. The initial degradation kinetics follow the intensity behavior predicted by the trap-todangling bond conversion model of Adler. Trace levels of impurities such as O and P significantly increase the initial degradation, also in accord with the predictions of the trap conversion model.