Simulation and analysis of low-resistance AlGaN/GaN HFET power switches

AlGaN/GaN HFETs yield excellent properties for highly-efficient power-switching devices. A key parameter of highly-efficient switches is the static on-state resistance of the transistor. This paper discusses the main parameters affecting the on-state resistance and in particular the influence of resistive metallization in lateral finger structures and large-area comb structures. Current crowding effects for finger structures are analytically analyzed and compared. Equations are developed and applied in practical examples and verified by two-dimensional finite element simulations. For lateral large-area comb structures different bond configurations are investigated. Furthermore, the two-dimensional simulations method has been applied on real structure layouts of a large-area power switch and the result of this simulation is compared to measurement results.