The Effect of Oxide Fixed Charge on the Breakdown Characteristics of SiC Lateral Super Junction Devices

In this paper, the positive and negative effects of oxide fixed charge on the breakdown characteristic of lateral SiC super junction devices are studied. Simulation results show that in the super junction devices with oxide layer, the negative (or positive) fixed charge on the SiO2/SiC interface act as a like p-pillar (or n-pillar) and enhance the depletion of n-pillar (or p-pillar), which result in a charge compensation and improvement of the breakdown characteristics of the devices. At the same time, a phenomenon of electric field crowding can be caused by the fixed charge and result in a decreasing of the breakdown voltage, this negative effect can be suppressed sufficiently by a field plate.