Impacts of Asymmetry Double Gate Structure on Reliability Degradation of Thin-Film Transistor With Nanosheet Channel

This work investigates the characteristics and reliability of double-gate (DG) and single-gate (SG) mode operations in polycrystalline-silicon nanosheet transistors (TFTs). It is observed that the threshold voltage and subthreshold swing in the DG mode are lower than those in the SG mode, while the on-state current is much higher. The DG mode provides better control over the channel potential, resulting in higher electron density and field-effect mobility. Moreover, the back-gate voltage can be used to adjust the threshold voltage of the TFT in SG mode. The impact of the back-gate voltage on the reliability of the device is also studied. The results indicate that the DG mode is more reliable than the SG mode under positive gate bias stress, as the DG mode has a stronger channel potential control ability. In contrast, the back-gate voltage has little effect on the reliability of the TFT in SG mode.