SiN-passivated Γ-gate Al0.27Ga0.73N/GaN high electron mobility transistors by using a shifted exposure method

Effective gate-length reduction, surface passivation, and a field-plate structure upon the gate-drain region of a Γ-gate Al0.27Ga0.73N/GaN high electron mobility transistor (HEMT) have been achieved at the same time. The present SiN-passivated device with a 0.6 μm gate length and a 0.6 μm long field plate has demonstrated superior dc and rf characteristics as compared to a conventional-gated structure. Physical insights of device performance with respect to different SiN layer thicknesses are also investigated.