A Kink-Effect-Free Poly-Si Thin-Film Transistor With Current and Electric Field Split Structure Design

In this paper, we propose a high-performance kink-effect-free bottom-gated polycrystalline (poly-Si) thin-film transistor with a drain-extended field plate (FP) structure. The extended-drain FP can distribute the electric field to the channel near the drain area and, particularly, can change the electron current path. The altered current path leads to a high current density and high electric field split structure that reduces the impact ionization at the drain area. Our experimental results show that the on-current of the proposed device is higher than that of the conventional structure, and the kink effect as well as the leakage current is simultaneously improved. Moreover, the device stability, such as threshold voltage shift and transconductance degradation under a high gate bias, is enhanced by the proposed drain-extended FP design. The current and electric field split structure is also beneficial in scaling down the device size for a better performance.