Enhanced performance and reliability for solid-phase crystallized poly-Si TFTs with argon ion implantation

Abstract

High-performance solid-phase crystallized (SPC) polycrystalline silicon thin-film transistors (TFTs) with argon ion implantation (argon-implanted poly-Si TFTs) are proposed in this study. Compared to the control poly-Si TFT, the argon-implanted poly-Si TFT has superior electrical characteristics, including lower threshold voltage, higher field-effect mobility, steeper subthreshold swing, lower trap state density, etc. These electrical performance improvements could be attributed to the fine microstructure of the SPC poly-Si film improved by deep argon ion implantation beyond the interface of amorphous Si and underlying oxide. Therefore, a high-quality poly-Si channel accompanied with larger grain size and lower grain boundary trap states could be obtained. Moreover, the argon-implanted poly-Si TFT also exhibits an improved hot-carrier stress immunity owing to reduced weak Si-Si or Si-H bonds from fewer grain boundaries in the poly-Si channel. (c) 2007 The Electrochemical Society.