【Device Papers】Reproducibility of 10 kV-class NiO/Ga₂O₃ heterojunction rectifiers

      Researchers from the University of Florida have published a dissertation titled " Reproducibility of 10 kV-class NiO/Ga₂O₃ heterojunction rectifiers " in Applied Physics A.

Abstract

      We summarize NiO/Ga₂O₃ vertical heterojunction rectifier results from two separate 2-inch diameter wafers with drift layer nominal thickness of 15 µm. For optimized edge termination dimensions, the breakdown voltages (V_B) in the regions of the wafers with the highest drift layer thickness (16.7–18.2 µm) and lowest background doping density (8 × 10¹⁵ cm⁻³) are consistently in the range 10-13 kV. Without edge termination, devices fabricated in the same areas show V_B of 8.3–8.8 kV. Over the entire wafer areas, the breakdown voltage can vary from 7.5-13 kV for the same optimized edge termination scheme. With a larger edge termination distance, the V_B is slightly improved. With a larger final metal extended distance, the V_B is significantly improved. With the radius of the final metal smaller than the extent of the NiO, the V_B is smaller or equal to the diodes without edge termination. There are two types of breakdown characteristic observed-in devices with abrupt increase in current near V_B, there is catastrophic breakdown at the edge of the final metal, whereas devices with gradual increases in current above 4–5 kV show no visible damage. The NiO/Ga₂O₃ rectifiers show negative coefficients of V_B of -12.9 V.K⁻¹, superior to that for Schottky barrier rectifiers fabricated on the same wafers, which exhibit values of -54.3 V.K⁻¹.

DOI：

https://doi.org/10.1007/s00339-025-08527-6