Improved operation stability of in situ AlSiO dielectric grown on (000–1) N-polar GaN by MOCVD

The impact of post-metallization annealing of N-polar AlSiO metal-oxide semiconductor (MOS) capacitors was investigated. Annealing in air at 320 °C and 370 °C reduced the density of near-interface traps from 5.6 × 1011 to ~2.8 × 1011 cm−2 and extended the region of flat-band voltage stability and low-leakage operation from 0–2.6 to 0–4 MV cm−1 in the forward bias accumulation region. Moreover, annealing at 370 °C fully suppressed the instabilities in the flat-band voltage within the test voltage range (−10 to −25 V) of depletion operation. The robust dielectric results demonstrated in this letter are promising for further enhancements of gate-robustness in N-polar GaN-based MOS-based transistors.