Iterative Numerical Method of Gate Turn-Off Thyristor: Comparative Study Between Si and SiC

Problem statement: Silicon (Si) has long been the dominant semiconductor of choice for high-power, high-temperature and high-frequency device applications. However, recently, wide bandgap semiconductors, particularly Silicon Carbide (SiC) has attracted because it offers tremendous benefits over other semiconductor materials in a large number of industrial and military. A change of technology from Si to SiC will revolutionize the power electronics and simulation is needed to predict their characteristics. Approach: The system of partial differential equations which forms the Poisson's and continuity equations together with appropriate boundary conditions cannot be solved explicitly in general. Therefore, the solution must be calculated by means of numerical approaches. Application of Finite Element Method (FEM) for semiconductor device simulation is described. It was shown that this method guarantees exact conservation of current both locally and at the device terminals. Finite element forms of Poisson's equation and the electron and hole current continuity equations were derived. Results: This study described the implementation of FEM in order to get the doping profile of the semiconductor devices. The switching simulation, 4H-SiC GTO thyristor was presented and tested numerically by predicting its performance using the 2-D simulator developed in this project. Conclusion: We calculated turn-off time and loss of SiC-GTO and compared with Si-GTO thyristor using 2-dimensional device simulation. Results showed that turn-off time and loss are smaller in SiC-GTO thyristor rather than Si-GTO thyristor.