High Power Linearity and Low Leakage Current of AlN/GaN/InGaN Coupling Channel HEMTs With N₂O Oxidation Treatment

This letter reports on a high-linearity and low-leakage current AlN/GaN/InGaN coupling-channel HEMT (CC-HEMT) utilizing the
$\text{N}_{{2}}\text{O}$
oxidation treatment process. Attributed to the channel coupling effect and the gate oxidation process, there is a significant improvement in both the leakage current and linearity figure of merit. The fabricated HEMT exhibited a low off-state leakage of 1.6 nA/mm, which achieves a high on/off current ratio of 109 for AlN-based transistors. The extrinsic
${f}_{\text {T}}$
and
${f}_{\text {max}}$
of the proposed CC-HEMT are 53 and 118 GHz, respectively. The two-tone power level linearity of the proposed CC-HEMT was characterized. The Ka-band output third-order intermodulation point (OIP3) and linearity figure of merit (LFoM) of OIP3/
${P}_{\text {DC}}$
are 36.4 dBm and 12.9 dB, respectively. These results highlight the application prospects of the AlN/GaN/InGaN CC-HEMT system for high-linearity and low-power consumption power amplifiers.