Effect of probe geometry during measurement of >100 A Ga2O3 vertical rectifiers.

The high breakdown voltage and low on-state resistance of Schottky rectifiers fabricated on β-Ga₂O₃ leads to low switching losses, making them attractive for power inverters. One of the main goals is to achieve high forward currents, requiring the fabrication of large area (>1 cm²) devices in order to keep the current density below the threshold for thermally driven failure. A problem encountered during the measurement of these larger area devices is the dependence of current spreading on the probe size, resistance, number, and geometry, which leads to lower currents than expected. We demonstrate how a multiprobe array (6 × 8 mm²) provides a means of mitigating this effect and measure a single sweep forward current up to 135 A on a 1.15 cm² rectifier fabricated on a vertical Ga₂O₃ structure. Technology computer-aided design simulations using the floods code, a self-consistent partial differential equation solver, provide a systematic insight into the role of probe placement, size (40–4120 μm), number (1–5), and the sheet resistance of the metal contact on the resultant current-voltage characteristics of the rectifiers. [ABSTRACT FROM AUTHOR]