Temperature Dependences of $I$ – $V$ Characteristics of SD and LDD Poly-Si TFTs

We have compared the temperature dependences of the current-voltage 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 (PAT), whereas that for the SD TFT shifts from PAT to band-to-band tunneling.