Investigation of Electrical Characteristics on AP-PECVD Fabricated Amorphous IGZO TFTs with Hydrogen Plasma Treatment

Abstract

TFT panel production process can be divided into three kinds of technology. There have amorphous silicon (a-Si), low-temperature polysilicon (LTPS) and amorphous IGZO (a-IGZO) oxide. Traditional amorphous silicon (a-Si) silicon has a lot of advantages such as good productivity, short process and low-cost. It also has a lot of shortcomings on these applications on TFTs such as photosensitivity, light degradation, and opacity, etc. The dispute of the material based on a-Si: H as an active layer in TFT is low field effect mobility (similar to 1 cm(2)/V.S) (M. Shur and M. Hack, J. Appl. Phys. 55, 3831 (1984)), photo sensitivity (low band gap about 1.7 V) and high deposition temperature (similar to 400 degrees C) (M. Shur, et al., J. Appl. Phys. 66, 3371 (1989); K. khakzar and E. H. Lueder, IEEE Trans. Electron Devices 39, 1438 (1992)). Amorphous In-Ga-Zn-O (IGZO) had attracted attention that compared with the conventional a-Si: H, in the past three years, a-IGZO thin film transistors is more popular which compared with the other oxide semiconductors, because of its larger I-on/I-off ratio (> 10(6)), smaller subthreshold swing (SS), better field-effect mobility and better stability against electrical stress. Hydrogen plasma treatment is applied in improving a-IGZO TFTs active layer, which is fabricated by atmospheric pressure-plasma enhanced chemical vapor deposition (AP-PECVD), the electrical characteristics of a-IGZO TFTs is investigated.