Microstructure and Optical Features of Nano-crystalline Si Films Prepared by PECVD Techniques as a Function of Reaction Gas and Substrate Temperature

초록

Nanocrystalline Si films were prepared by PECVD. We investigated the crystallinity, nanostructure and optical characteristics of the nc-Si films as a function of deposition parameters such as reaction gas and substrate temperature, and discussed the relations of the optical and nanostructural features of the films with process variables. The nc-Si films prepared at R.T. in a reaction gas of 10<S<30% exhibited an optical band gap of about 3 eV; the band gap varies depending on the process variable sensitively. The films with nano-crystallites as well as amorphous grain boundaries, which were prepared at R.T. in S=30%, exhibited significant PL phenomena. On the contrary, the films which were prepared at 500oC in S=30%, did not exhibit any such PL.