The influence of oxygen partial pressure on the properties of sputtered vertical NiO/β-Ga2O3 heterojunction diodes

In this work we present studies on the influence of oxygen partial pressure on the properties of sputtered vertical NiO/β-Ga 2 O 3 heterojunction diodes. Obtained results shows substantial effect of oxygen partial pressure on the electrical properties of NiO/β-Ga 2 O 3 heterojunction diodes. The diodes with NiO layers deposited in pure Ar shows Schottky-like I-V characteristics with low ideality factor of 1.05 and barrier height of 1.27 eV as well as low turn-on voltage close to 1V. On the other hand, diodes with NiO layer deposited in oxygen containing atmosphere shows typical p-n diode characteristics. The best electrical characteristics i.e. low on-state resistance of 2.85 mΩcm 2 , lack of defects and low ideality factor down to 1.07 at RT along with high breakdown voltage close to 900V without any junction termination, were obtained for diodes with NiO layers deposited at 50 % oxygen content. We have demonstrated that by optimization of oxygen partial pressure, the properties of NiO/β-Ga 2 O 3 heterojunction diodes can be tuned and excellent electrical performance in terms of low-on state resistance, high breakdown voltage, low-leakage current and low ideality factor, can be obtained.