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This paper systematically studies high-current-induced effects, hot-carrier effects, and self-heating effects in flexible low-temperature polycrystalline-silicon thin-film transistors fabricated on polyimide. By utilizing I – V and various-frequency C – V measurements, the exact location of defects generated by the self-heating effects can be clarified. The degradation mechanism is found to originate from asymmetric negative-bias temperature instability. After clarifying this mechanism, the self-heating effects were shown to be alleviated by manipulating the fabrication of the buffer layer, thereby improving heat dissipation capabilities. [ABSTRACT FROM PUBLISHER]

Thickness of buffer layers affects performance of flexible polycrystalline silicon thin film transistors (TFT). A thicker buffer SiO2 film demonstrates better endurance to thermal expansion stress from the polyimide substrate. However, the thickness of buffer SiO2 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). [ABSTRACT FROM AUTHOR]

This letter investigates flexible polycrystalline silicon thin film transistor performance variation due to different buffer layer thicknesses. In flexible electronics, thermal expansion stress during device fabrication is inevitable. A thicker SiO2 buffer demonstrates better endurance to thermal expansion stress from the polyimide substrate during device annealing. However, if the SiO2 buffer thickness is above a critical point, its weak heat dissipation capability causes the optimal ELA crystallization condition to shift. A thermal expansion stress simulation and TEM photos were utilized to verify performance variation. Furthermore, a similar trend was observed in electrical characteristics after negative bias temperature instability. [ABSTRACT FROM PUBLISHER]