Papers by Keyword: Laser Crystallization

Abstract: Pulsed laser was demonstrated to be effective for the crystallization of amorphous hydrogenated silicon (a-Si:H) films deposited on Si wafer. The amorphous films were deposited on (111) Si wafers by plasma enhanced chemical vapor deposition (PECVD). The crystallization treatment was carried out by a low frequency Nd:YAG laser. The crystallinity modifications induced by the laser treatment were evidenced by X-ray diffraction and atomic force microscope (AFM). The influence of laser frequency on the crystallization degree was analyzed in detail. The better crystallinity was obtained at the laser frequency of 10Hz.

Abstract: In this work, the crystallization of different silicon based thin films as the precursor of crystallization was investigated by femto-second laser with 800 nm wavelength. The linear absorption coefficient of a-Si films at that wavelength is quit lower than the other structures of Si-based thin film, which has no related with the incident light energy. However, we found that the crystallization of a-Si films was better than μc-Si films as the precursor. We use Z-scan techniques to prove that the two-photon absorption effect would be responsible for the crystallization. And unlike the linear absorption, the two-photon absorption effect is correlated with the incident light energy, as well as the micro-structure of the silicon based film. At the end of the paper, the crystallization by laser with wavelength longer than the absorption limit was discussed.