Power high-voltage and fast response Schottky barrier diamond diodes

• We developed and fabricated power high-voltage and fast response packaged vertical Schottky barrier diamond diodes.
• Diodes demonstrated 5 A forward current and more than 1000 V blocking voltage in the temperature range from 20 °C to 250 °C.
• Packaged diamond diodes provided the lowest reported on-resistance of 0.2 Ω for diode case at room temperature.
• Low specific on-state resistance of 35 mΩ × cm2 was achieved at 4 V due to forward current self-heating effect.
• The drift layer resistance minimum provides feedback for the diamond diode crystal self-stabilization at optimal temperature.

We developed and investigated a set of packaged vertical diamond Schottky barrier diodes (SBDs) with a large crystal area of up to 25 mm2. All devices show forward current above 5 A and the blocking voltage over 1000 V in the temperature range from 20 °C to 250 °C. Due to the large crystal area and finite thermal resistance of the crystal-case interface the forward current self-heating effect results in a good diamond SBDs performance not only at elevated temperatures but also at normal conditions. As a result we measured about 4 V forward voltage drop, 35 mΩ × cm2 specific on-resistance and 100 nA/cm2 leakage current for the diode case at room temperature. At a case temperature of 250 °C the forward voltage drop was less than 2.5 V, the specific on-resistance about 40 mΩ × cm2 and the leakage current about 100 μA/cm2. The Baliga's figure of merit was 25–30 MW/cm2 in the temperature range of 20-250 °C. The typical value of the reverse recovery time less than 10 ns while switching from 2 A forward current to 100 V blocking voltage meets the requirements for practical use of diamond SBDs in effective switch-mode power converters operating at frequencies higher than 1 MHz. Further device design optimization and the diamond epitaxial layer quality improvement will help to reduce the power losses in on-state and make diamond SBDs competitive with SiC diodes even at room temperature.