The compact microcrystalline Si thin film with structure uniformity in the growth direction by hydrogen dilution profile
The hydrogen dilution profiling (HDP) technique has been developed to improve the quality and the crystalline uniformity in the growth direction of μc-Si:H thin films prepared by hot-wire chemical-vapor deposition. The high H dilution in the initial growth stage reduces the amorphous transition layer from 30-50 to less than 10 nm. The uniformity of crystalline content Xc in the growth direction was much improved by the proper design of hydrogen dilution profiling which effectively controls the nonuniform transition region of Xc from 300 to less than 30 nm. Furthermore, the HDP approach restrains the formation of microvoids in μc-Si:H thin films with a high Xc and enhances the compactness of the film. As a result the stability of μc-Si:H thin films by HDP against the oxygen diffusion, as well as the electrical property, is much improved.