Long-Term Recovery Behavior in InSnZnO Thin-Film Transistors after Negative Bias Stress

In this work, long-term recovery behavior in InSnZnO thin-film transistors (TFTs) after negative bias stress (NBS) is systematically investigated for the first time. The on-state current (I on ) increases rapidly within 10 s NBS and then recovers after the removal of the NBS. However, the threshold voltage continuously negatively shifts with time. After NBS within four days, InSnZnO TFTs with shorter channel length (L) exhibit a larger I on degradation rate under NBS and a larger I on recovery rate, whereas the I on recovery rate is almost the same irrespective of L after the four days of recovery. Incorporating TCAD simulations, a degradation and recovery model, considering defect trap and detrap process, is tentatively proposed. The test results and the proposed model would be advantageous in the practical application of InSnZnO TFTs for high-quality active matrix displays.