NiGa$_{2}$O$_{4}$ interfacial layers in NiO/Ga$_{2}$O$_{3}$ heterojunction diodes at high temperature

Kingsley Egbo; Emily M. Garrity; William A. Callahan; Chris Chae; Cheng-Wei Lee; Brooks Tellekamp; Jinwoo Hwang; Vladan Stevanovic; Andriy Zakutayev

paper

NiGa $_{2}$ O $_{4}$ interfacial layers in NiO/Ga $_{2}$ O $_{3}$ heterojunction diodes at high temperature

arXiv:2401.06924

Abstract

NiO/Ga $_{2}$ O $_{3}$ heterojunction diodes have attracted attention for high-power applications, but their high-temperature performance and reliability remain underexplored. Here we report on the time evolution of the static electrical properties in the widely studied p-NiO/n-Ga $_{2}$ O $_{3}$ heterojunction diodes and the formation of NiGa $_{2}$ O $_{4}$ interfacial layers when operated at $55 0^{\circ}$ C. Results of our thermal cycling experiment show an initial leakage current increase which stabilizes after sustained thermal load, due to reactions at the NiO-Ga $_{2}$ O $_{3}$ interface. High-resolution TEM microstructure analysis of the devices after thermal cycling indicates that the NiO-Ga $_{2}$ O $_{3}$ interface forms ternary compounds at high temperatures, and thermodynamic calculations suggest the formation of the spinel NiGa $_{2}$ O $_{4}$ layer between NiO and Ga $_{2}$ O $_{3}$ . First-principles defect calculations find that NiGa $_{2}$ O $_{4}$ shows low p-type intrinsic doping, and hence can also serve to limit electric field crowding at the interface. Vertical NiO/Ga $_{2}$ O $_{3}$ diodes with intentionally grown 5 nm thin spinel-type NiGa $_{2}$ O $_{4}$ interfacial layers show excellent device ON/OFF ratio of > 10 $^{10}$ ( $\pm$ 3 V), V $_{O N}$ of ~1.9 V, and breakdown voltage of ~ 1.2 kV for an initial unoptimized 300-micron diameter device. These p-n heterojunction diodes are promising for high-voltage, high-temperature applications.

16 pages, 5 figures

NiGa2​O4​ interfacial layers in NiO/Ga2​O3​ heterojunction diodes at high temperature

Abstract

NiGa $_{2}$ O $_{4}$ interfacial layers in NiO/Ga $_{2}$ O $_{3}$ heterojunction diodes at high temperature