Strong Polarization AlN/GaN/Si Heterojunction MIS-HEMT for Mm-Wave Low-Voltage Terminal Applications

In this paper, we present an AIN/GaN metal-insulator-semiconductor high electron mobility transistor (MISHEMT) on a Si substrate, utilizing in-situ SiN as the gate dielectric, demonstrating exceptional mm-wave performance at low supply voltages. Facilitated by the thin in-situ SiN layer, a low ohmic contact resistance$(R\mathrm{c})$of 0.2$\Omega$.mm was achieved. The device, featuring a T-shape gate with a 104 nm gate foot length$(L\mathrm{G})$and a total gate metal thickness of 620 nm, exhibited a maximum drain current$(I_{\mathrm{D}})$of 1.44 A/mm, a peak transconductance$(g_{\mathrm{m}\max})$of 449 mS/mm, and a cut-off frequency/maximum oscillation frequency$(f_{\mathrm{T}}/f\max)$of 130/210 GHz. Under 28 GHz load-pull conditions and with a drain voltage of 5/10 V, the device delivered maximum output power densities$(P_{\text{out}\max})$of 0.66/2.10 W/mm, and a peak power-added efficiencies (PAE) of 39%/35%. These outstanding results underscore the vast potential of A1N/GaN HEMTs on Si for power amplifiers (PAs) in mobile mm-wave front-end applications.