Insulating gate III-N heterostructure field-effect transistors for high-power microwave and switching applications

We describe the properties of novel III-N-based insulating gate heterostructure field-effect transistors (HFETs). For the gate isolation, these devices use either SiO2 layer (in metal-oxide-semiconductor HFET (MOSHFET) structures) or Si3N4 layer (in metal-insulator-semiconductor HFET structures). These insulating gate HFETs have the gate-leakage currents 4-6 orders of magnitude lower than HFETs, even at elevated temperatures up to 300 degreesC. A double-heterostructure MOSHFET with SiO2 gate isolation exhibits current collapse-free performance with extremely low gate-leakage current. Insulating gate devices, including large periphery multigate structures, demonstrate high-power stable operation and might find applications in high-performance power amplifiers and microwave and high-power switches with operating temperatures up to 300 degreesC or even higher.