| This research focuses on the modeling, design, optimization and characterization of Silicon Carbide bipolar junction transistor (SiC BJT). A two-dimensional numerical device simulator ISETCAD is used to model, design and optimize the SiC BJT's cell structure. A base resistance model has been developed for the SiC BJT and the model is used to evaluate the layout of the real SiC BJTs. A number of important SiC BJT characteristics that are different from Si BJT, such as the current gain, conductivity modulation, emitter size effect and the difference between BVceo, and BV cbo are investigated theoretically and experimentally. The dynamic characteristics section mainly focuses on the comparison of SiC BJT power loss versus popular Si power devices like Si IGBT. The small energy loss and a square reverse biased safe operation area (RBSOA) of the SiC BJT are theoretically and experimentally demonstrated, along with an analysis of SiC switching characteristics. Short-circuit capability has been investigated for the SiC BJT. The unique SiC BJT operational degradation issue is investigated through a series of experiments and possible degradation mechanisms are identified. The Ph.D research also includes the design and fabrication of a monolithic solution of SiC BJT and SiC rectifier for the first time. The characterization of the BJT/rectifier device is given in this dissertation. This novel device will help the system to reduce the size, cost and increase the reliability. Based on the BJT structure, some novel device structures are also proposed in this work. Simulation study results have shown that these devices are very promising to further improve the performance of SiC BJTs. |
