Optimisation of a power 4H–SiC SIT device for RF heating applications

In this paper, the optimisation procedure for a static induction transistor (SIT) in silicon carbide is described and its application in a typical RF heating circuit is presented. A field plate edge termination is optimised for a 10 μm thick epitaxial layer with doping in the range 1015 cm−3 to 1016 cm−3. Results show a breakdown voltage of 1280 V, corresponding to 68% of the theoretical value. For the chosen application an epitaxial layer doping level of 5×1015 cm−3 is revealed to offer the best compromise. This allows pinch off of drain voltages exceeding 600 V from a 20 V gate drive whilst achieving a current density of 250 A cm−2 at an on-state voltage of less than 1 V. Transient simulations are performed for a series load resonant converter with a switching frequency of 27.12 MHz. The results emphasise the suitability of the device for RF heating applications.