Oxygen plasma enhanced crystallization of a-Si for low thermal budget poly-Si TFTs on Corning 7059 glass

Abstract

A new fabrication process for advanced polycrystalline silicon thin film transistors on 7059 glass substrates has been developed. This unique fabrication process has the advantage of short processing time at low processing temperatures (/spl les/600/spl deg/C). The processing is based on the key step of an oxygen plasma treatment of precursor amorphous silicon (a-Si) films prior to crystallization. This plasma treatment enhances the thermal crystallization process and reduces the crystallization thermal budget substantially. The viability of this new crystallization process is demonstrated with n-channel thin film transistors with mobility values of 35 cm/sup 2V s, on/off current ratios 4/spl times/10/sup 6/ and threshold voltages of 0.5 V.<>