High-Quality Polycrystalline Silicon Film Crystallized from Amorphous Silicon Film using NiCl2 Vapor

Abstract

The development of high-quality polycrystalline silicon film is of interest for active-matrix organic light-emitting displays. Here, NiCl2 vapor was applied for the first time to enhance the crystallization of amorphous silicon film. The crystallization of amorphous Si showed that round-shaped Si grains grow and become impinged to form polyhedral-shaped grains with diameters of 10 to 25 μm. It was found that the growth of large grains was possible via the merging of fine needle grains with the same directional growth. The crystallized film showed a high degree of crystallinity and a very smooth surface with a roughness of 0.53 nm. The field-effect hole mobility and subthreshold swing of the p-channel thin-film transistor fabricated using the poly-Si film were 113 cm2/ and 0.4 V/decade, respectively. The high performance of the thin-film transistor is attributed to the large grain size, the high crystallinity, the low Ni contamination and the smooth surface of the poly-Si film crystallized in NiCl2 vapor.