Hot Carrier Effects in Low-Temperature Polysilicon Thin-Film Transistors

We have studied the reliability of a low-temperature polysilicon (poly-Si) thin-film transistor (TFT). The drain avalanche hot electron effect was characterized by changing the stress gate and drain voltage dependence. Generation of hot carriers was confirmed using an emission microscope. It was found that the degradation was improved by the lightly doped drain (LDD) structure. A degradation model was proposed and analyzed along with a two-dimensional device simulator. Reasonable agreement with the experimental results was successfully obtained. It was found that the density of state (DOS) of poly-Si was increased by the hot carrier effect locally around the drain region.