High-performance E-mode GaN MIS-HEMT for Power Switching Applications

GaN-based wide-bandgap semiconductor devices are promising for future high power and high frequency applications. In particular, the GaN high electron mobility transistor (HEMT) grown on large-size Si substrate is ideal for high power switching device applications with low cost potential. The GaN HEMT based convertors and inverters have been demonstrated for electric vehicle (EV) applications. To achieve high switching efficiency and low current collapse GaN devices, there are many device/process issues have to be solved. These include the careful design of epitaxial structure and the suitable gate insulator for MIS (metal-insulator-gate)-HEMT device structure. Furthermore, surface passivation technique is crucial to achieve low dynamic on-resistance (Ron) and good reliability. Moreover, for safety consideration, a normally-off device is a must. Several approaches to achieve normally-off device will be presented in this talk, including gate recess, F⁻ ion implantation, high-k interlayer MOS-HEMT and novel hybrid ferroelectric charge-trapping gate stack approaches. Finally, power modules with high-performance GaN-on-Si HEMT are demonstrated for power switching device applications.