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

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-H-2 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. (C) 1998 American Institute of Physics. [S0003-6951(98)00419-7].