III-nitride metal-insulator-semiconductor heterojunction field-effect transistors using sputtered AlON thin films

Abstract

In this letter, a III-nitride metal-insulator-semiconductor heterostructure field-effect transistors (MISHFET) was demonstrated by incorporating a sputtered AlON layer in the AlGaN∕GaN heterostructure field-effect transistors (HFET). The AlON layer was deposited on the HFET structure by magnetron sputtering, followed by rapid thermal annealing at 850°C for 45s. A reverse gate leakage current that is four orders of magnitude lower was obtained in the MISHFET, compared to that in HFET. The MISHFET also shows 20% increase in the drain saturation current. For a MISHFET with 1-μm-long gate, the current gain cutoff frequency, ft and the power gain cutoff frequency, fmax are measured to be 13 and 37GHz, respectively.