The continuous advance of silicon power electronics has been made possible due to a well established materials foundation that has allowed power switching transistors to incorporate sophisticated device concepts, e.g. superjunction, junction termination extension, etc. The push to very high voltage silicon devices is primarily limited by its modest critical electric field when compared to materials such as silicon carbide and gallium nitride which have ~10x better theoretical breakdown performance. Si may still benefit from exploratory technologies to achieve higher voltage operation. However, the trade-off between switching speed, blocking voltage, and forward voltage drop cannot be fundamentally overcome for bipolar devices as it has been for unipolar devices with the superjunction, which has pushed DMOSFETs to surprisingly new performance levels. Silicon carbide, an indirect semiconductor, is an excellent candidate for wide bandgap minority carrier device technologies with high blocking voltages and low forward voltage drop. Some limitations to ultimate performance are high quality thick epitaxial layers and surface electric field termination. These two issues have been the focus of intense research recently and progress has been steady. Stable 10kV P-i-N diodes have been evaluated in our lab at temperatures above 200°C, however more work is needed to see sufficiently long working lifetimes in both forward and reverse operation. Specific challenges lie in reducing the basal plane dislocation density within the thick epitaxial layers, which lead to stacking fault generation and reduced current flow, and finding alternative surface passivation layers to handle the high surface electric fields and high temperatures typical of SiC devices. For many power electronics applications in the 10kV or less regime, SiC unipolar devices are preferred over bipolar minority carrier devices primarily due to improved switching speed. Unipolar devices have recently demonstrated extraordinary switching performance and lower voltage (1.2kV) SiC Schottky barrier diodes are now commercial products. SiC DMOSFETs with blocking voltages over 10kV have been demonstrated with a specific on-resistance ~0.2 ohm-cm@super 2@. Common material challenges exist with bipolar devices in the area of electric field termination and high temperature, high electric field surface passivation. Additionally, reliable MOSFETs demand extremely high quality gate dielectrics with very low interface state density and low fixed charge. The wide bandgap of SiC places additional burden on the gate and passivation dielectrics against charge injection from the semiconductor. Material challenges in Si and SiC power devices will be reviewed with emphasis on the most recent results that show a trend of performance to much higher voltage operation. Beyond high voltage devices, characteristics necessary for reliable large area, high current power devices will be discussed.