Diamond p-Type Lateral Schottky Barrier Diodes With High Breakdown Voltage (4612 V at 0.01 mA/Mm)

Diamond p-type lateral Schottky barrier diodes (SBDs) with a 2-μm-thick drift layer are fabricated with and without Al2O3 field plates. Schottky contacts composed of Mo (50 nm) / Pt (50 nm) / Au (100 nm) showed a barrier height of 1.02 ± 0.01 eV and ohmic contacts of Ti (30 nm) / Pt (30 nm) / Au (100 nm) achieved a specific ohmic contact resistance of 1.25 ± 0.98 × 10-4 Ω-cm2. Their forward and reverse bias characteristics are studied in detail. Both SBDs, with and without Al2O3 field plates, exhibit rectifying ratios larger than 107 at room temperature, and a peak current density of 5.39 mA/mm under 40 V forward bias at 200 °C. The leakage current density at room temperature is stable at approximately 0.01 mA/mm for both diodes. The SBD without the Al2O3 field plate exhibited a breakdown voltage of 1159 V, while the SBD with the Al2O3 field plate is stable under a reverse voltage of 4612 V, which is higher than many diamond SBDs previously reported.