Photo-learkage-current distribution in a-Si and poly-Si TFTs

摘要

A rear irradiation OBIC (Opetical Beam Induced Current) measurement system has been developed to tinvestigate photo-leakage-current distribution of a-Si and poly-Si thin film transistors (TFTs). By using the system, a-Si property dependence of the photo-leakage-current distribution was analyzed. The photo-leakage-current is generated at the drain electrode side where the positive voltage is applied because a photo-generated hole passed throgh the channel region of the TFT. The photoleakage-current decreases with decreases in the hole transportation in a-Si. In the case of poly-Si TFT investigation, the photo-leakage-current of offset gate structure was analyzed. It is clearly observed that the photo-leakage-current is observed in tne offset region of the TFTs. The photo-leakeage-current can be decreased bylightly doping the offset region with phosphorus which reduces the hole mbility in this reigon.