Correlation between electron mobility and silicon-hydrogen bonding configurations in plasma-hydrogenated polycrystalline silicon thin films

Abstract

This letter describes the relationship between electron mobility and Si-hydrogen bonding configurations in poly-Si thin films after plasma-hydrogenation treatment. A 50-nm-thick amorphous-Si film was crystallized by excimer laser irradiation followed by plasma hydrogenation. Measurements of the Hall effect and Raman scattering demonstrated that mobility increased under the Si-H dominant state and decreased under the Si-H2 dominant state, which were respectively caused by adjusted and excessive hydrogenation times. Mobility degradation was recovered by dissociation of excess H atoms by annealing. The origin of the correlation is discussed in terms of imperfections such as grain boundaries and in-grain defects.