It is characterized and discussed about hydrogenated amorphous silicon thin film transistors (a-Si:H TFTs) fabricated by photo-CVD method. Amorphous silicon TFTs which are used to drive the flat panel displays have been studied heavily and great improvement has been achived, but there were still remained some issues such as low mobility and stability problems. Flat panel Displays drived by a-Si TFTs fabricated by PECVD method has been commercialized. But PECVD method has fundamental problem. That is, there are defects in thin films induced by plasma. To eliminate this problem, it is proposed and characterized about a-Si TFTs fabricated by photo-CVD method.
The structure of devices is Top-Gate, and subthreshold slope of it is 0.2 V/dec, switching ratio ($I_{on}/I_{off}$)is $10^5$, and threshold voltage is 1.5 V.
