Lateral Growth of Poly-Si Film by Excimer Laser and Its Thin Film Transistor Application

Abstract

Thin Si film on a SiO 2 membrane has been recrystallized by single-shot excimer laser. Since there is no substrate acting as a heat sink to the latent heat in the molten Si film, the heat flow can be reduced immensely and also controlled well to form a temperature gradient along the membrane, resulting in the lateral growth of large grains, more than 70 µ m in length and a few µ m in width. Two thin film transistors (TFTs) with the channels parallel and perpendicular to the grain boundary, were fabricated using the laterally grown poly-Si film. The parallel TFT showed the maximum field-effect mobilities of more than 600 cm 2 /Vs for electrons and about 300 cm 2 /Vs for holes.