Power Loss Limit in Unipolar Switching Devices: Comparison Between Si Superjunction Devices and Wide-Bandgap Devices

Power loss limits in unipolar switching devices are theoretically evaluated with both conventional (CO) and superjunction (SJ) structures. Si-based SJ devices and wide-bandgap semiconductor (SiC and GaN)-based CO devices are compared under the minimum loss conditions with respect to power losses, device areas, and heat generation densities. For the wide-bandgap devices, the losses are several times smaller, and the areas are less than one tenth of the Si devices for the same rating. On the other hand, the heat densities of the wide-bandgap devices were approximately one order of magnitude larger than those of the Si devices.