Abstract
Precursor a-Si films are deposited by RF planar magnetron sputtering in argon gas at 200 °C substrate temperature. Properties of the a-Si films have large dependences on sputtering gas pressure. Sheet resistance of polycrystalline Si films which are phosphorus-ion-implanted and crystallized with Ar-laser- irradiation shows low for sputtering gas pressures of from 1.0 to 1.5 Pa. Moreover, the Si films have smaller concentrations of argon and oxygen impurities in film. Polycrystalline Si thin film transistors (poly-Si TFTs) are fabricated using Si films which are sputtered at 1.0 Pa gas pressure and crystallized by Ar-laser irradiation. The polycrystalline Si films feature column structure with near 200 nm grain size. Gate SiO2 films in the poly-Si TFTs are also deposited through sputtering in oxygen and argon mixed gas. The poly-Si TFTs annealed in hydrogen atmosphere shows excellent characteristics of very high mobility.
