Design and modeling of a novel 4H-SiC normally-off BMFET transistor for power applications

Abstract

First numerical simulation results targeted to the design of a novel 4H-SiC normally-off Bipolar Mode Field Effect Transistor (BMFET) are presented. Starting from a commonly available 4H-SiC epitaxial wafer, with an epitaxial layer with a thickness of a few tens of microns, and considering a completely planar device structure where the highly doped source and gate regions are defined by means of implant technology, the developed analysis predicts the feasibility of a transistor well suitable for high power applications, with a very high current gain, a forward current density up to 1 kA/cm2, an on-state output resistance in the order of few mΩ×cm2 and a blocking voltage in the range of 1–2 kV. The 4H-SiC fundamental physical models, such as the doping incomplete ionization and the carrier recombination processes, were carefully taken into account during the simulations. Modeling the device output characteristics in the various operation conditions (off-state, active region, saturation), the role of different design parameters was investigated.