Effect of Buffer Layers on Performance and Reliability of Polycrystalline Silicon TFTs Fabricated on Polyimide

摘要

Thickness of buffer layers affects performance of flexible polycrystalline silicon thin film transistors (TFT). A thicker buffer SiO_2 film demonstrates better endurance to thermal expansion stress from the polyimide substrate. However, the thickness of buffer SiO_2 film would causes the variation of optimal excimer laser annealing (ELA) crystallization condition. In addition, the simulation results shows that the non-uniform stress in the gate insulator is more pronounced near the poly-silicon/gate insulator edge and at the two sides of the poly-silicon protrusion. It would affect the stability results and device performance. By optimization the process condition, the device would still have good device performance after operating under high temperature (60 □) and long period of time (500hrs).