Ultrascaled 10 nm T‐gate E‐mode InAlN / AlN HEMT 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 10 9 , subthreshold swing 78 mV/dec, and DIBL 100 mV/V), and smaller 10 nm foot length of Tgate 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 f T (583 GHz), and maximum oscillation frequency f max (840 GHz). At room temperature, the calculated carrier density and mobility are 2.8 Â 10 13 cm À2 and 1250 cm 2 /Vs. The large Jhonson figure of merit (f T . V BR ) 19.23 THz and (f T . f max ) 1/2 699 GHz shows the potential of the proposed device for high-power millimeter-wave applications.

Numerical study of T-Gate AlGaN/AlInGaN/GaN MOSHEMT with Single and Double Barrier for THz Frequency Applications

“…Thus, the gate voltage at the maximum Gm should be used as the gate polarization to approximate ft and fmax. Equation (13) demonstrates that fmax is influenced by ft and other factors (where GDS represents drain-to-source conductance and RS, RG stand for source and gate resistance, respectively).The cutoff frequency and the maximum oscillation frequency referred to the frequencies when the curves of the current gain H21 and the power gain Ug are unity [38]. Their expressions in relation to S-parameters is described in equations ( 14) and ( 15): The measurements were conducted at a drain-to-source voltage (VDS) of 8 V and a gate-to-source voltage (VGS) of 4 V, corresponding to the peak transconductance (Gm).…”