Temperature Dependences of Transistor Characteristics of Single-Drain and Lightly-Doped-Drain Poly-Si TFTs

Abstract

We have compared temperature dependences of transistor characteristics between single-drain (SD) and lightly-doped-drain (LDD) poly-Si thin-film transistors (TFTs). It is found that the temperature dependence of the off-leakage current for the LDD TFT is larger because the electric field at the drain junction is weaker. Moreover, the change of the temperature dependence from low drain voltage (V ds) to high V ds for the LDD TFT is smaller because the main mechanism of the off-leakage current is always phonon-assisted tunneling, whereas that for the SD TFT shifts from the phonon-assisted tunneling to the band-to-band tunneling.