Design Strategy and Numerical Investigation of Vertical β-Ga₂O₃ Schottky Barrier Diodes With Compound Termination Extension

We report vertical
$\boldsymbol {\beta }$
-gallium oxide (
$\boldsymbol {\beta }$
-Ga2O3) Schottky barrier diodes with compound termination extension (CTE-SBDs) structures combining dielectric-filled groove termination extension (GTE) and multiple floating metal rings (FMRs). The proposed CTE structures can effectively suppress premature breakdown and enhance the reverse blocking capability of unipolar vertical Ga2O3 devices by homogenizing the electric field distribution at the edge of the Schottky anodes. The CTE design can be simply accomplished by a dry-etching and dielectric-filling process, which eliminates the requirements of the immature and challengeable implantation process to realize the junction termination extension (JTE) structures. We systematically investigated the impact of the key design parameters on the performance of devices by numerical simulation and found that the spacing, width, and number of the FMRs, as well as the thickness of the dielectric layer, are intimately associated with the electric field distribution and reverse performance of the vertical Ga2O3 CTE-SBDs. With optimum parameters, the breakdown voltage (BV) of the multi-ring CTE-SBDs features a tremendous improvement from 909 V in the conventional Schottky barrier diode (SBD) to 3357 V, with a minor increase in the specific on-resistance from 5.63 to 6.10 m
$\boldsymbol {\Omega }\cdot $
cm2, leading to a Baliga’s figure of merit (BFoM) of 1.847 GW/cm2. These results provide a practicable scheme and design guidelines for vertical Ga2O3 power electronic devices toward high-voltage, high-speed, and high-power applications.