N-shot SLS-processed polycrystalline silicon TFTs

Abstract

In this paper, we focus on a variation of the 2-shot sequential lateral solidification (SLS) process for crystallization of thin Si films for TFT applications. The resulting microstructure is engineered to reduce the large discrepancy in directionality of the TFTs with respect to the lateral growth direction. Through this method, we are able to improve the mobility directionality ratio between devices with majority carrier flow parallel and perpendicular to the lateral growth direction, respectively, from 0.3 to over 0.7. Further post-SLS process thinning and planarization of the Si surface is used to improve the uniformity of device characteristics.