GaN and SiC devices' input capacitance: an experimental characterization

Gallium Nitride High Electron Mobility Transistors (HEMTs) and Silicon Carbide power MOSFET devices represent enabling technologies whose characteristics can overcome conventional Silicon theoretical limits and make power electronics systems more compact, efficient, and cost-effective. In order to fully exploit the high-frequency performance of these devices, an accurate input capacitance model, either physical or experimental, has to be developed to describe the device's dynamic behavior. Among the different figures of merit which characterize the performance of the device, such as threshold voltage variation, on-resistance, and input capacitance, the latter can have a significant role in determining the transient response of the device, and so its switching speed. In this work, an experimental characterization of GaN HEMT and SiC input capacitance is proposed, where the on transition is kept as a reference to derive the behavior of the capacitance as a function of switching frequency.