374GHz cut-off frequency of ultra thin InAlN/AlN/GaN MIS HEMT

We report ultra thin InAlN/GaN Metal-Insulator-Semiconductor High Electron Mobility Transistor (HEMT) with AlN spacer layer by achieving 374GHz current gain cut-off frequency. The lattice matched InAlN/AlN/GaN HEMT with a 0.17 fraction of Indium content was enhanced the high frequency characteristics with a 30nm gate length by prevent the dissemination of short channel effects. A thin oxide layer is used above the InAlN barrier layer to reduce the gate leakage current in the two orders of magnitude. The HEMT shows an RF extrinsic Transconductance (g_m) is 835 mS/mm, gate-to-source capacitance (C_gs) is 264fF/mm and gate-to-drain capacitance (C_gd) is 33fF/mm. A maximum drain current density (I_d) of 1.9 A/mm is acquired. The electron mobility of 1256 cm²/V-s, two-dimensional electron gas (2DEG) concentration is 2 × 10¹⁹ cm^-3 and the electron velocity of 1.91 × 10⁷ cm/s has achieved. These results are in well correspondence with the fabricated device available in the literature.