Reproducible and High-Temperature Performance of NiO/ $\beta$-Ga2O3 Vertical Rectifiers in Achieving 8.9 kV Breakdown

The increasing electrification of automobiles and the need to switch renewable energy sources in the existing power grid has increased the demand for energy-efficient power electronics capable of higher voltage and currents than existing Si devices. This has focused attention on the wide and ultra-wide bandgap semiconductors, with the latter including diamond, AlN and Ga 2 O 3 . The ability to grow large-diameter, high-quality crystals and the attendant low cost of production has spurred interest in $\beta$ -Ga 2 O 3 . [1] The lack of p-type doping options for Ga 2 O 3 has led to the use of p-type oxides to form p-n heterojunctions with the n-type Ga 2 O 3 . The most successful has been NiO, deposited by sputtering.[2]–[4] Optimizing the heterojunction rectifier device structure is crucial to achieve a high-power figure of merit (FOM) for power electronic devices, defined as (V B ) ² /R ON where V B is the reverse breakdown voltage and R ON -is the on-state resistance. A less studied aspect has been the elevated temperature performance of such devices. We report an investigation of the uniformity of achieving high V B and low R ON , as well as the temperature dependent performance of NiO/Ga 2 O 3 vertical rectifiers. A new highest V B and highest-temperature voltage blocking capability for these devices are achieved.