Experimental study of Ni/TiO2/β-Ga2O3 metal–dielectric–semiconductor diodes using p-NiO junction termination extension.

This work demonstrates TiO₂/β-Ga₂O₃ metal–dielectric–semiconductor (MDS) diodes with an average breakdown field beyond the material limits of SiC and GaN. These MDS diodes have lower conduction losses and higher breakdown voltage (V_bk) than the cofabricated Schottky barrier diodes (SBDs), simultaneously improving both on- and off-state parameters that are typically in competition with each other. With further optimized field management using p-NiO guard rings (GRs), the Ni/TiO₂/β-Ga₂O₃ MDS diodes present a path to realistically utilize the high critical field of Ga₂O₃ without large forward conduction losses from a high-barrier junction. MDS diodes showed a lower V_on (0.8 V) than the SBDs (1.1 V) from linear extrapolation of the current density-voltage (J-V) curve. The MDS diode had higher V_bk of 1190 V (3.0 MV/cm) compared to 685 V (2.3 MV/cm) for the SBD, and the MDS diode with the p-NiO guard ring saw further improvement with V_bk of 1776 V (3.7 MV/cm) compared to 826 V (2.5 MV/cm) for GR SBD. The BFOM (V_bk²/R_on,sp) of 518 MW/cm² for the GR HJD is competitive with other literature results. A new figure of merit that includes the impact of turn on voltage is also proposed and demonstrated in this paper, which highlights how diodes perform in a practical high-power operation. This full paper is derived from the proceeding abstract of Willams et al. [IEEE Device Research Conference, Santa Barbara, CA, 25-28 June 2023 (IEEE, New York, 2023)]. [ABSTRACT FROM AUTHOR]