Simulation, characterization and design of epitaxial emitter NPN 4H-SiC BJTs for amplifier applications

We have analyzed the implementation of a 4H-SiC NPN high voltage BJT as a small signal amplifier transistor. From experimental characterization and intrinsic device modeling, we determined that the factors limiting performance are base transport considerations and an inefficient layout for high frequency applications. Approaches such as improving base transport and base series resistance are suggested in order to achieve 4H-SiC BJTs with UHF and lower microwave frequency capabilities. Using two-dimensional numerical simulations, we present an improvement on the existing design wherein the intrinsic device modeling suggests a unity gain frequency f_T of approximately 5 GHz.