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/ $\beta $ -gallium oxide ( $\beta $ -Ga2O3) p-n heterojunction diode (HJD) with high breakdown voltage and low leakage current. Without any composite termination structure, the CuCrO2/ $\beta $ -Ga2O3 HJD reached a high breakdown voltage of 1.46 kV with low leakage current of $10~\mu $ A/cm2, which is almost four times improvement over the traditional $\beta $ -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 m $\Omega \cdot $ 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/ $\beta $ -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 $\beta $ -Ga2O3 bipolar power diodes.