Power high-voltage and fast response Schottky barrier diamond diodes

Abstract

We developed and investigated a set of packaged vertical diamond Schottky barrier diodes (SBDs) with a large crystal area of up to 25mm2. All devices show forward current above 5 A and the blocking voltage over 1000V 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 4V forward voltage drop, 35mΩ×cm2 specific on-resistance and 100nA/cm2 leakage current for the diode case at room temperature. At a case temperature of 250°C the forward voltage drop was less than 2.5V, the specific on-resistance about 40mΩ×cm2 and the leakage current about 100μA/cm2. The Baliga's figure of merit was 25–30MW/cm2 in the temperature range of 20-250°C. The typical value of the reverse recovery time less than 10ns while switching from 2A forward current to 100V blocking voltage meets the requirements for practical use of diamond SBDs in effective switch-mode power converters operating at frequencies higher than 1MHz. 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.