Effects of self-aligned field induced drain with double spacer on the characteristics of poly-Si TFT

摘要

The electric characteristics of Field Induced Drain (FID) poly-Si thin film transistors (poly-Si TFF's) with an independently biased self-aligned sub gate using a double space process are investigated. The FID poly-Si TFT reduced the off-state leakage and enlarged the on/off current ratio compared with conventional and LDD(Lightly Doped Drain) TFTs. The self-aligned double spacer process removed the sub gate misalignment error and the length of the sub gate can be easily controlled by poly-Si thickness and hard mask. As the effective sub gate length is increased, the drive current is decreased. However, the optimum sub gate length and voltage are investigated with the on/off state currents and the hot carrier degradation effects.