Low-Temperature Polysilicon Thin Film Transistors by Non-Mass-Separated Ion Flux Doping Technique

A low-temperature, high-throughput self-aligned poly-Si TFT fabrication process has been developed. The process includes two key techniques. The first one is a laser-induced crystallization of a-Si occurring in the solid phase using a CW Ar+ laser beam with high scanning speed, which was previously reported. The second is large-diameter ion flux doping without mass separation. The maximum processing temperature is 450°C, which is sufficiently low for use of inexpensive glass substrates. With this process, excellent poly-Si TFT characteristics of Ion/Ioff>106 and µFE=40 cm2/(V s) were obtained.