Vertical NiO/β-Ga2O3 rectifiers grown by metalorganic chemical vapor deposition

Abstract

The performance of vertical Schottky and NiO/β-Ga2O3 p-n heterojunction rectifiers in which the Ga2O3 was grown by metalorganic chemical vapor deposition (MOCVD) is reported. The Si-doped Ga2O3 drift layers employed in the study had a doping concentration of 7.6 × 1015 cm−3 with a thickness of approximately 6 μm. High-angle annular dark-field scanning transmission electron microscopy imaging revealed an absence of interfacial features or extended defects around the drift layer region, indicating that MOCVD provides high-quality β-Ga2O3 epitaxial films for fabrication of vertical rectifiers. Both Schottky and NiO/Ga2O3 p-n heterojunction rectifiers attained the highest reported breakdown voltage of 486 and 836 V, respectively, for this growth technique. The heterojunction rectifiers showed an on/off ratio surpassing 109 within the voltage range of 0 to −100 V. Additionally, the Schottky barrier diodes demonstrate an on/off ratio of up to 2.3 × 106 over the same voltage range. These findings highlight the promise of MOCVD as a growth method for the type of rectifiers needed in power converters associated with an electric vehicle charging infrastructure.