Silicon carbide in power electronics: Overcoming the obstacle of bipolar degradation

Silicon Carbide (4H-SiC) is an ideal semiconductor for energy efficient power conversion modules. In recent years, unipolar SiC devices have been conquering the power electronics market. Contrarily, the commercialization of bipolar SiC devices has been hindered by the so-called bipolar degradation, which is closely related to the existence of certain structural defects within the active device volume. It will be shown how these critical defects can be avoided by optimizing the epitaxial growth of the active device volume. Furthermore, it will be proven that the absence of critical defects in the device prevents bipolar degradation. As the root cause of bipolar degradation is solved now, we also present remaining challenges for the commercialization of bipolar devices such as the cost reduction by enhancing the epitaxial growth rate and the improvement of device characteristics by increasing the minority carrier lifetime.