Improved Electrical Performance of MILC Poly-Si TFTs Using CF4 Plasma by Etching Surface of Channel

Abstract

In this letter, a new manufacturing method for metal-induced lateral crystallization (MILC) polycrystalline silicon thin-film transistors (poly-Si TFTs) using CF4 plasma was proposed. It was found that CF4 plasma effectively minimizes the trap-state density by etching away the top surface of MILC and passivating the trap states, leading to superior electrical characteristics such as high field-effect mobility, low threshold voltage, low subthreshold slope, low leakage current, and high ON-/OFF-current ratio. CF4-Plasma MILC TFTs also possess high immunity against the hot-carrier stress and thereby exhibit better reliability than that of conventional MILC TFTs. Moreover, the manufacturing processes are simple (without any additional thermal annealing step) and compatible with MILC TFT processes.