Influence of the Beam Irradiation Conditions on an Si Film Melting-Crystallized by a Nd:YAG Pulse Laser Beam with Linear Polarization

Abstract

We investigated the influence of the irradiation conditions of the coherent length and the polarization of the laser beam, the incident angle θi, the pulse number, the fluence, the substrate temperature and the a-Si film thickness on the melting-crystallization of an a-Si film and the controllability of the periodic grain boundary location by using a linearly polarized laser beam. For formation of periodic grain boundary in the crystallized Si film, the linear polarization is key factor rather than the coherent length. Also, the a-Si film thickness should be around 60 nm for large optical absorption, and the high substrate temperature and the large pulse number are preferable. By using a p-polarized beam, the grain boundary width can be expanded proportional to 1/(1-sin θi) roughly. In order to suppress the ablation of the film and to increase the productivity, the fluence should be adjusted precisely.