Effect of Rising Time on AC Stress-Induced Performance Degradation in a-ITGZO Thin-Film Transistors

In this study, we investigate the impact of rising time on alternating current (AC) stress-induced degradation in amorphous indium-tin-gallium-zinc oxide (a-ITGZO) TFTs through both experiments and simulations. When AC bias stresses with rising and falling times (t_r-f) of 400 ns, 200 ns, and 100 ns were applied to the a-ITGZO TFTs, the threshold voltage (V_TH) shifted positively by 0.97 V, 2.68 V, and 2.83 V, respectively. These experimental results align with a stretched exponential model, which attributes the V_TH to electron trapping in bulk dielectric states or at interface traps. The simulation results further validate the stretched exponential model by illustrating the potential distribution across the dielectric and channel layers as a function of t_r-f and the density of states in the a-ITGZO TFT.