A Novel Blocking Technology for Improving the Short-Channel Effects in Polycrystalline Silicon TFT Devices

An original blocking technology is proposed for improving the short-channel characteristics of polycrystalline silicon thin-film transistors (poly-Si TFTs). In particular, two types of modified devices called poly-Si TFT with block oxide and poly-Si on partial insulator (POPI)-TFT are designed for the first time in this field to enhance device performance. The proposed TFT structures can significantly reduce short-channel effects when compared with a thick source/drain (S/D) poly-Si TFT (i.e., the fully depleted TFT). In addition, an ultrathin (UT) S/D structure (UT-TFT) is designed to verify that the block oxide TFT devices do achieve improved performance without needing the thin active layers and ultrashallow junction depth. Also, the POPI-TFT is found to reduce the thermal instability through its natural body-tied scheme.