The present status of the silicon carbide and gallium nitride bipolar power semiconductor devices is reviewed. Several unipolar and bipolar figures of merit have been examined to demonstrate the potential performance gain to be obtained from silicon carbide and gallium nitride based power devices. Several conventional as well as novel device structures have been examined, some of which have already been demonstrated and others are in their early stages of development. Conventional silicon theory has often been found to be inadequate to explain the characteristics of silicon carbide. Appropriate modifications have been applied to investigate more complicated characteristics of silicon carbide devices.