Performance enhancement of offset gated polysilicon thin-film transistors

Simple offset gated n-channel polysilicon thin film transistors (TFTs) of channel length L=10 μm were investigated in relation to the intrinsic offset length /spl Delta/L and the polysilicon quality. For /spl Delta/L/spl les/1 μm, the device parameters such as threshold voltage, subthreshold slope and field effect mobility are improved, while the leakage current remains unchanged. In TFTs with /spl Delta/L>1 μm, the leakage current decreases with increasing the offset length. When the polysilicon layer is of high quality (large grain size and low intra-grain defect density), the leakage current is completely suppressed without sacrificing the on-current in TFT´s with offset length of 2 μm.