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

In this letter, a III-nitride metal-insulator-semiconductor heterostructure field-effect transistors (MISHFET) was demonstrated by incorporating a sputtered AION layer in the AIGaN/GaN heterostructure field-effect transistors (HFET). The AION layer was deposited on the HFET structure by magnetron sputtering, followed by rapid thermal annealing at 850degreesC for 45 s. 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-mum-long gate, the current gain cutoff frequency, f(t) and the power gain cutoff frequency, f(max) are measured to be 13 and 37 GHz, respectively. (C) 2005 American Institute of Physics.