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 degrees C and 370 degrees C reduced the density of near-interface traps from 5.6 x 10(11) to similar to 2.8 x 10(11) 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 degrees 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.