Demonstration of Ni/NiOx/β-Ga2O3 heterojunction diode with F plasma pre-treatment for reducing on-resistance and reverse leakage current

In this work, we demonstrated the NiOx/beta-Ga2O3 heterojunction with reduced reverse current and on-resistance via F plasma pre-treatment. The band offsets and the elemental composition of the heterojunction are investigated by X-ray photoelectron spectroscopy. It shows that the valence and conduction band offsets of the NiOx/p-Ga2O3 heterojunction decrease with F plasma pre-treatment. The on-current of Ni/NiOx/beta-Ga2O3 heterojunction diodes increases from 10(-3) to 11.82 A/cm(2), which corresponds to the on-resistance of 100 to 0.2 Omega cm(2) , and the ideality factor decreases from 2.42 to 1.06. For less than 40 V reverse bias, the leakage current of the heterojunction can be suppressed with F pre-treatment. It is reduced from 10(-5) to 10(-6) A/cm(2) under -20 V bias. In addition, the electrical properties of the heterojunction are restored after thermal cycling. The n-type NiOx and interface F plasma pre-treatment processes exhibit good temperature stability. These observations in the Ni/ NiOx/p-Ga2O3 heterojunction with the F plasma pre-treatment show a great potential in improving the performance of gallium oxide-based heterojunctions.