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 AlON layer in the $\mathrm{Al}\mathrm{Ga}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ heterostructure field-effect transistors (HFET). The AlON layer was deposited on the HFET structure by magnetron sputtering, followed by rapid thermal annealing at $850°\mathrm{C}$ for $45\mathrm{s}$ . 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 $1\text{‐}\mu \mathrm{m}$ -long gate, the current gain cutoff frequency, $f_t$ and the power gain cutoff frequency, $f_{\max }$ are measured to be 13 and $37\mathrm{GHz}$ , respectively.