Modeling of the Steady State and Switching Characteristics of a Normally Off 4H-SiC Trench Bipolar-Mode FET

The electrical characteristics of a normally off 4H-silicon carbide (SiC) bipolar-mode FET are investigated by means of a careful design activity and an intensive simulation study useful for a first-time-ever realization of this device in SiC. Specific physical models and parameters strictly related to the presently available 4H-SiC technology are taken into account. The device basically consists of a trench vertical JFET operating in the bipolar mode that takes full advantage of the superior material properties. A drain-current density up to 500 A/cm², a forced current gain on the order of 50, and a specific on-resistance as low as 1.3 mΩ·cm² are calculated for a 1.3-kV blocking voltage device. The turn-off delay is on the order of a few nanoseconds. The presented analysis is supported by experimental results on the p-i-n diodes embedded in the device structure.