Electrical performance of triple implanted vertical silicon carbide MOSFETs with low on-resistance

This paper describes results of 6H silicon carbide vertical power MOSFETs designed for different blocking capabilities: 600V and 1600V. The fabrication is based on a triple implantation technique with a lateral inversion channel. The MOSFETs are normally off and exhibit specific on-resistances of 22 and 40 mΩcm2, resp. A chip area of 1 mm2 has emerged as a suitable value in order to achieve an acceptable yield with respect to the blocking capability. A SiC MOSFET of this size can be driven up to 1 A in continuous operation. As expected for a unipolar device short turn-on and turn-off delay times have been measured. In particular, due to a very small accumulation zone the Miller capacitance is small in comparison to Si MOSFETs. The switching speed can be influenced by the gate driving circuit in a wide range. The SiC MOSFET is controllable in all switching states and stable up to 125°C case temperature. The switching behavior tested under conditions typical for motor drives is robust against short cuts and short time overloading.