Fast switching 4H-SiC V-groove trench MOSFETs with buried P+ structure

4H-SiC trench MOSFETs with novel V-groove structures have been investigated. We have fabricated trench MOSFETs with the inclined 4H-SiC{0-33-8} face [1, 2] as trench sidewalls for the channel region, resulting in a low specific on-resistance owing to the superior MOS interface properties. In addition, by using buried p⁺ regions inside the drift layer, a high voltage avalanche breakdown without oxide break was realized as well. The specific on-resistance and breakdown voltage were 3.5 mΩ cm² (V_GS = 18 V, V_DS = 1 V) and 1700 V, respectively. The switching capability of the trench MOSFET demonstrated fast dynamic characteristics without adverse effects in comparison to the trench MOSFET without buried p⁺ regions. Typical turn-on and turn-off time for the switching were estimated to be 92 ns and 27 ns, respectively from the resistive load switching measurements at a drain voltage of 600V.