Ultrascaled 10 nm T‐gate E‐mode <scp>InAlN</scp> / <scp>AlN HEMT</scp> with polarized doped buffer for high power microwave applications

Abstract

The DC and RF performance of ultra-scaled 10 nm E mode InAlN/AlN HEMT with polarized doped buffer has been investigated. The proposed device has the feature of polarized doped buffer, heavily doped source/drain region, and recessed T-gate structure. The polarization-induced doping in the buffer layer bent the conduction band upwardly convex, which enhanced the 2DEG confinement, reduced the buffer leakage current, and significantly uplifted the breakdown voltage (33 V), which is 5 times higher than the conventional InAlN/AlN GaN buffer HEMT (8 V). The short channel effect was further reduced by the recessed gate engineering (high on/off ratio 109, subthreshold swing 78 mV/dec, and DIBL 100 mV/V), and smaller 10 nm foot length of T-gate reduced the parasitic capacitance, which uplifts the RF parameters of the proposed device. The proposed device exhibits a high current density of 2.8 A/mm, transconductance 1.55 S/mm, cutoff frequency fT (583 GHz), and maximum oscillation frequency fmax (840 GHz). At room temperature, the calculated carrier density and mobility are 2.8 × 1013 cm−2 and 1250 cm2/Vs. The large Jhonson figure of merit (fT. VBR) 19.23 THz and (fT. fmax)1/2 699 GHz shows the potential of the proposed device for high-power millimeter-wave applications.