It is known that the direct contact between Al and a-Si enhances the crystallization of a-Si film. But the poly-Si films crystallized by the direct contact of Al metal film suffer the problems of rough surface and voids. In our study, we utilized for the first time the AlCl3 vapor instead of Al metal film to enhance crystallization. The AlCl3 vapor successfully enhanced the crystallization of a-Si films so that the crystallization was completed in 5 h at 540degreesC. Moreover, the surface of the crystallized film was as smooth as that of the a-Si film and no voids were found. The Al incorporation into the poly-Si film was confirmed using secondary ion mass spectroscopy. (C) 2002 Elsevier Science B.V. All rights reserved.