Authors: Y. Li and B-S Lee
Affilation: National Chiao Tung University, Taiwan
Pages: 86 - 89
Keywords: polysilicon TFT, single-gate, double-gate, surrounding-gate, 3d simulation
Thin-film-transistors (TFTs) with high mobility and low leakage current are desirable in many applications especially in liquid crystal display (LCD).We have computationally analyzed electrical properties of thin film transistors using three-dimensional (3D) simulation. It is known that the performance of TFTs is limited by the large amount of randomly oriented grain boundaries (GBs) existing in the channel. Furthermore, the random grain orientation leads to significant device-to-device variation and poor circuit yield. To improve the performance of TFT, we for the first time explore and compare the electrical characteristics of the polysilicon TFT with different gate structures. By evaluating the transfer and output characteristics, the surrounding-gate polysilicon TFTs demonstrate better driving capability than that of single-gate and double-gate. It mainly results from that the surrounding-gate TFTs with a sufficiently large coverage ratio, and can improve short channel effects [1-3]. If we have better driving capability of polysilicon TFT transistors, we can increase the performance of pixel as well as possible. So the plate size will become large and brightly colored.