TCAD Based Reliability Assessment of Recess Gate AlGaN/GaN HEMT with Negative Gate Bias Induced Stress

In the present work, the effect of negative gate bias induced stress on the performance of conventional and Recess Gate AlGaN/GaN HEMT has been presented using ATLAS TCAD simulation. Different device parameters have been used to investigate the influence of device parameters on the threshold voltage of the devices after applying negative gate bias induced stress. Results show that the recess gate architecture reduces the effect of negative gate bias stress due to the lower 2DEG density. Also, it is observed that, scaling down the gate length results in a significant degradation in the device pinch off voltage on subjecting it to a negative stress which is expected to be due to the presence of interface traps present in the device. The increase in gate leakage current in case of Recess gate HEMT has been lowered by using nitride layer at the drain end which also shows approximately the same device behavior after applying negative gate bias stress.