Method of optimizing channel characteristics using multiple masks to form laterally crystallized ELA poly-Si films

摘要

A method is provided to optimize the channel characteristics of thin film transistors (TFTs) on polysilicon films. The method is well suited to the production of TFTs for use as drivers on liquid crystal display devices. The method is also well suited to the production of other devices using polysilicon films. Regions of polycrystalline silicon can be formed with different predominant crystal orientations. These crystal orientations can be selected to match the desired TFT channel orientations for different areas of the device. The crystal orientations are selected by selecting different mask patterns for each of the desired crystal orientation. The mask patterns are used in connection with lateral crystallization ELA processes to crystallize deposited amorphous silicon films.