Vertical GaN Junction Barrier Schottky Diode with p-NiO/n-GaN Hetero-Junction

Selective-area p-type doping in GaN has been regarded as one of the key challenges for vertical junction-based GaN devices. Nickel oxide (NiO) has been demonstrated as a p-type semiconductor and has shown great potential in GaN power electronic devices. In this work, a vertical GaN-on-GaN junction barrier Schottky (JBS) diode featuring p-NiO/n-GaN hetero-junction and p-NiO junction termination extension structure has been demonstrated. Owing to the modulated hole concentration by post-deposition annealing in the p-NiO layer, the fabricated JBS diode exhibits an improved breakdown voltage of ~620 V. Meanwhile, a relatively low turn-on voltage of ~0.64 V and a differential RON of ~1.85 mΩ \(\cdot\) cm2 have been achieved by the hybrid anode combining Schottky junction and p-NiO/n-GaN hetero-junction. Furthermore, the influence of hole concentration in p-NiO on reverse leakage characteristics has also been discussed. This work shows the potential of p-NiO/n-GaN hetero-junction in building up junction-based vertical GaN power devices.