Effects of silicon-hydrogen bond characteristics on the crystallization of hydrogenated amorphous silicon films prepared by plasma enhanced chemical vapor deposition

The crystallization behavior of hydrogenated amorphous silicon (a-Si:H) films prepared by plasma enhanced chemical vapor deposition is investigated in view of the silicon-hydrogen (Si-Hn) bond characteristics. A-Si:H films deposited at various pressures (0.1-1.0 Torr) are annealed to polycrystalline silicon (poly-Si) films in a conventional vacuum furnace at 600 °C. The final grain size in the poly-Si films increases with the deposition pressure, up to 1.6 μm in the case of the films deposited at 1.0 Torr. The Si-Hn bond characteristics are analyzed by Fourier transform infrared spectroscopy and modified gas chromatography for hydrogen thermal evolution experiment. Finally, the Si-Hn bond characteristics are suggested to be an important factor affecting the crystallization behavior of a-Si:H films, which is also related to the film stress as well as the structural disorder in a-Si network.