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 (~1 cm²/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 (~400 °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 Ion/Ioff ratio (>106, 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.
ABSTRACT
In the past few years, thin film transistors have a wide range of applications on display technology, material selection and quality for its active layer is critical for device performance. 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 (~1 cm²/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 (~400 °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, due to its good properties of simultaneously high/low conductivity with high visual transparency via doping level. Oxide-based semiconductors, such as ZnO (G. Adamopoulos, et al., Appl. Phys. Lett. 95, 133507-3 (2009); H.-C. Cheng, et al., Appl. Phys. Lett. 90, 012113-3 (2007)) and IGZO (C. J. Chiu, et al., Electron Device Letters, IEEE 31, 1245 (2010); L. Linfeng and P. Junbiao, IEEE Transactions on Electron Devices 58, 1452 (2011)) have been reported for the active channel layer. These oxide-based materials offer good electrical properties and high transparency for thin film transistors, its high transmittance can be applied to fabricate the full transparent TFT on flexible substrate. With In-Situ hydrogen plasma treatment on a-IGZO produced by atmospheric pressure-plasma enhanced chemical vapor deposition (AP-PECVD), the material characteristics of a-IGZO is studied.
