Patent ID: 7195992
Filing Date: 2007-03-27
Classification: H01L

Abstract:
1. A method for crystallizing a polysilicon layer on a wafer, the method comprising: forming a first amorphous silicon layer; selectively introducing a crystallizing agent on the amorphous layer in a substantially symmetric pattern in two dimensions; and annealing the wafer to form the crystallized polysilicon layer, wherein substantially no amorphous silicon remains between silicon grains in the polysilicon layers, wherein the crystallizing agent is silicon nuclei, wherein the step of selectively introducing a crystallizing agent in a substantially symmetric pattern comprises: forming a mask layer on the first amorphous silicon layer; etching holes in the mask layer, the holes distributed in a substantially symmetric pattern and exposing portions of the first amorphous layer; and depositing silicon nuclei on the mask layer and the exposed portions of the first amorphous layer.