(Invited) High-Performance Top-Gate and Double-Gate Low-Temperature Polycrystalline-Silicon Thin-Film Transistors Fabricated Using Continuous-Wave-Laser Lateral Crystallization on a Glass Substrate

A high-quality polycrystalline silicon (poly-Si) film is a technology for improving the performance of low-temperature (LT) poly-Si thin-film transistors (TFTs). We have already developed continuous-wave-laser lateral crystallization (CLC) using a diode-pumped solid-state laser to improve the crystalline quality of the thin poly-Si film. In this paper, we report on two approaches for improving the performance of LT poly-Si TFTs, which are based on a thin CLC poly-Si film and are fabricated at 550 oC on a glass substrate. The first approach is a combination of a CLC poly-Si film and sputtered HfO2 as the gate dielectric. The other approach is a combination of a CLC poly-Si film and a double-gate structure for realizing four-terminal LT poly-Si TFTs. The former exhibited an enhancement in the on-current that was four times greater than a device with a silicon dioxide gate stack. In the latter, high controllability of the threshold voltage was confirmed.