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

In this letter, an AlGaN/GaN MOS-HEMT was demonstrated using a 5-nm-thick SiOxdielectric layer deposited by plasma enhanced chemical vapor deposition (PECVD) as a gate insulator. The fabricated device exhibits a maximum IDScurrent of 570 mA/mm at VGS=+ 3 V, an ON-state resistance (Rbioscon) of 7.3 · 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 (Vp) shift was observed during the IDS-VGShysteresismeasurements giving an estimated interface state density (Dit) as low as 3.9 × 1011cm-2eV-1. These results demonstrate the high quality of the SiOx/AlGaN interface and the efficiency of the passivation process. To the best of our knowledge, this is the lowest reported Diton an AlGaN/GaN MOS-HEMT device using a PECVD deposition technique.