A novel laser-processed self-aligned gate-overlapped LDD poly-Si TFT

A novel process for fabricating self-aligned gate-overlapped LDD (SAGOLDD) poly-Si thin film transistors (TFTs) was demonstrated. Laser irradiation for dopant activation was performed from the backside of the quartz wafer. The graded LDD structure was naturally formed under the gate edges due to the lateral diffusion of the dopants during the laser activation. In comparison with the conventional laser-processed self-aligned poly-Si TFTs, the SAGOLDD poly-Si TFTs exhibited lower leakage current, suppressed kink effect, and higher reliability. Moreover, the proposed process was simple and very suitable for low-temperature processing.