Study of GaN HEMTs degradation by numerical simulations of scattering parameters

Gallium Nitride has proved by now to be one of the most interesting compound semiconductors for high-speed and high-power technological applications. Its wide bandgap makes it a suitable solution for sustaining high voltages, and its ability to form heterojunctions, together with its high saturation velocity, makes it an exceptional candidate for the fabrication of High-Electron Mobility Transistors (HEMTs). However, the most critical issue of GaN-based devices is reliability: a number of technological solutions like surface passivation, field-plate structures, and gate recessing have been developed in the last years in order to overcome reliability problems both in dc and RF operation.