Simulation study of silicon carbide Clustered Insulated Gate Bipolar Transistor (CIGBT)

Power semiconductor devices are inevitable parts of a power electronic converter system, with nearly 50% of electricity used in the world controlled by them. Silicon power devices have been used in power systems ever since the vacuum tubes were replaced by them in the 1950s. The performance of devices in a circuit is decided by the switching strategies and the inherent device performance like its on-state voltage, turn-on and turn-off times and hence their losses. Due to their inherent material properties, the growing interest in wide band gap devices is in applications beyond the limits of Si or GaAs. SiC is a wide bandgap material with properties that make it an attractive alternative to Silicon for high power applications.
Silicon Insulated Gate Bipolar Transistor (IGBT) is the most favourable device in the industry today for medium/high power applications. Silicon Clustered Insulated Gate Bipolar Transistor (CIGBT) is experimentally proven to demonstrate better performance as compared to their IGBT counterparts. In this work, the theoretical limit of silicon CIGBT is studied in great detail and compared to previously predicted IGBT limit. Later part of this thesis would explain the design and optimization of CIGBT in 4H- SiC. An in-depth simulation study of the same device is performed for both static and dynamic characteristics. Both planar and trench gate CIGBT devices are discussed here along with possible fabrication process. Along with this, a comparison study between CIGBT with its equivalent IGBT in SiC is also performed through extensive 2D simulations in MEDICITM in terms of their static and dynamic characteristics. Finally, a comparative study of P channel and N channel SiC CIGBT devices is evaluated through simulations.