TCAD Analysis on Suppression of Hot-Carrier Degradation of the Four-terminal Poly-Si TFTs

Four-terminal poly-Si TFTs with a counter-doped body terminal connected to the floating channel have superior immunity to both DC and dynamic hot-carrier (HC) degradation. With three-dimensional TCAD simulation, the underlying suppression mechanisms are clarified to be respectively the weakened parasitic BJT effect and lowering of the drain electric field by carrier injection from the body terminal for the DC and AC cases. Dependence of the degradation suppression on the position and width of the terminal is analyzed. A wider body terminal or that closer to the drain has better suppression effect.