Hydrogenation and direct-substitutional doping of evaporated amorphous silicon films

The addition of hydrogen during the evaporation of silicon has been shown to improve the electrical properties of the resulting a-Si film considerably by saturation of dangling bonds, if molecular dissociation takes place. Evaporation onto a substrate at room temperature and subsequent annealing has been shown to yield a film with a high resistance. It has been found that preparation at elevated substrate temperatures improves the photoconductivity further, and that adding phosphine to the hydrogen atmosphere during the evaporation produces efficient phosphorus doping.