AlGaN/GaN MOS-HEMT Device Fabricated Using a High Quality PECVD Passivation Process

Abstract

In this letter, an AlGaN/GaN MOS-HEMT was demonstrated using a 5-nm-thick SiOx dielectric layer deposited by plasma enhanced chemical vapor deposition (PECVD) as a gate insulator. The fabricated device exhibits a maximum ${I}_{{\text {DS}}}$ current of 570 mA/mm at ${V}_{{\text {GS}}} =+ {3}$ V, an ON-state resistance ( ${R}_{\mathrm {biosc{on}}}$ ) of $7.3~\Omega \cdot $ mm, a maximum transconductance peak of 180 mS/mm, and a gate leakage current below 1 nA/mm at a gate voltage of +/−3 V. Moreover, a very low pinchoff voltage ( ${V}_{p})$ shift was observed during the ${I}_{{\text {DS}}}$ – ${V}_{\text {GS}}$ hysteresis measurements giving an estimated interface state density ( ${D}_{\text {it}})$ as low as $3.9\times 10^{ {11}}$ cm $^{-2}$ eV $^{-1}$ . These results demonstrate the high quality of the SiO x /AlGaN interface and the efficiency of the passivation process. To the best of our knowledge, this is the lowest reported ${D}_{\text {it}}$ on an AlGaN/GaN MOS-HEMT device using a PECVD deposition technique.