Reduction of photo leakage current of hydrogenated amorphous silicon thin film transistors

The amorphous silicon thin film transistors (a-Si TFT) is particularly advantageous to the production of large screen displays and facilitates mass production. When applying an a-Si:H layer, the main objectives are enhancing the field effect mobility and reducing the off-state photo leakage current under backlight illumination. The increasing of the field effect mobility results in wide application of a-Si:H TFTs in high resolution of Liquid crystal displays (LCD). On the other hand, a-Si:H has high photoconductivity that results in high photo leakage current of a-Si:H TFT under light illumination. The objective of this study focused on applying experimentation and simulation to obtain optimal parameters for the amorphous hydrogenated silicon thin film of AM-LCDs. A short description is provided for the relationship of processing-structure-property. Based on the experimentation, we have found that the photo-leakage current of a a-Si-H thin film could be reduced by about 65% on the basis of low RF power and precise control of pressure and substrate temperature for the processing.