A Comparative study on Total Ionizing Dose Effects of 100-V Split-gate Trench VDMOS and Conventional Trench VDMOS

In this paper, we present a comparative study on the effects of Total Ionizing Dose (TID) radiation on the Split-Gate Trench VDMOS (SGT-MOS) and the conventional Trench VDMOS (T-MOS), both with equal rated breakdown voltages of 100 V, using experimental methods. The experimental findings reveal that the same degradation trends in the threshold voltage (V th ) were found for both types of devices. However, the breakdown voltage (BV) of SGT-MOS exhibits greater sensitivity to TID radiation compared to the T-MOS. Utilizing Sentaurus TCAD, we analyze and discuss the variances in BV shifting behavior between the SGT-MOS and T-MOS. The differences in BV shifting behavior between SGT-MOS and T-MOS can be attributed to the positive oxide trapped charges induced by TID, which could significantly affect the electric field distribution for SGT-MOS, but not for T-MOS. To address this issue, three methods are proposed to enhance the TID tolerance for the SGT-MOS and T-MOS. These methods include avoiding high-temperature processes, reducing the thickness of the oxide layer, and decreasing the doping in the drift layer.