First Demonstration of CuCrO2/β-Ga2O3 p-n Heterojunction Diode With High Breakdown Voltage and Low Leakage Current

We demonstrate for the first time a high-performance CuCrO₂/β-gallium oxide (β-Ga₂O₃) p-n heterojunction diode (HJD) with high breakdown voltage and low leakage current. Without any composite termination structure, the CuCrO₂/β-Ga₂O₃ HJD reached a high breakdown voltage of 1.46 kV with low leakage current of 10 μA/cm², which is almost four times improvement over the traditional β-Ga₂O₃ Schottky barrier diodes (SBDs). Simultaneously, the HJD exhibited a turn-on voltage of 1.62 V and a relatively low specific on-resistance of 5.36 mΩ⋅cm², yielding a power figure of merit (PFOM) of 0.4 GW/cm². The measurements of temperature-dependent current density–voltage (J–V) showed that the HJD exhibited good thermal reliability and carrier transport got increasingly dominated by interface recombination at higher temperatures. Furthermore, a type-II band alignment was identified in the CuCrO₂/ β-Ga₂O₃ heterojunction with a valence band offset of 2.22 eV and a conduction band offset of 0.45 eV, respectively, as determined by the X-ray photoelectron spectroscopy (XPS) characterizations. Technology computer aided design (TCAD) simulations indicated that the depletion region primarily extended into the Ga₂O₃ epitaxial region due to the full depletion of the p-CuCrO₂ layer, which contributes to a more uniform distribution of electric field and higher breakdown voltages. Evidently, these results indicate that the formation of heterojunction by introducing a p-CuCrO₂ layer is feasible and effective for achieving high-performance and improving manufacturing of β-Ga₂O₃ bipolar power diodes.