Investigation of plasma-oxidized aluminium as a gate dielectric for AlGaN/GaN MISHFETs

摘要

Nitride-based metal insulator semiconductor heterostructure field effect transistors (MISHFETs) have shown great potential, recently. An elegant technological approach is presented to fabricate MISHFETs with the gate dielectric formed only in the gate region. Aluminium is deposited in the gate region, oxidized by an inductively coupled oxygen plasma, subsequently covered by the evaporated gate contact metal and finally lifted off, all using a single patterning step. The electrical properties of the dielectric fabricated in this manner can be enhanced by annealing. Leakage currents comparable to those of other dielectric deposition methods are achieved. A subthreshold swing below 80 mV dec~(-1) indicates a high-quality interface.