The influence of plasma annealing on electrical properties of polycrystalline Si

Polycrystalline silicon doped with phosphorus and boron was prepared by low-temperature CVD and was annealed in a hydrogen/nitrogen plasma at 300 °C. The dopants were introduced by ion implantation and the concentration ranged from 2×1016 to 2×1019 cm−3. Plasma annealing decreased the poly-Si resistivity, which is significant at particular doping concentrations depending on density of localized states. The effect is due to reduction of deep localized states through hydrogenation and is canceled by additional annealing in nitrogen at 600 °C.