High-voltage diamond Schottky rectifiers

In this paper, we simulate and fabricate diamond Schottky rectifiers. The growth rate of pure diamond single crystal epitaxial is from 0.5 up to 100μm/hr with boron doping concentration around 1×1014 cm^-3 to 1×10¹⁶ cm^-3. A "liftoff" technology is used to provide the wafer. Theoretical calculation indicates that the diamond Schottky rectifier has a significant lower voltage drop than SiC Schottky rectifier and comparable with SiC PiN diode with the blocking voltage higher than 10 kV. A maximum 50 kHz operating frequency at switching voltage 25 kV is shown based on thermal limit. Vertical structure devices with 70μm epi layer achieve 18 A/cm² at 250°C at 7 V forward drop as shown with a breakdown voltage of only 600 V. A breakdown voltage of 8 kV at 100μm distance is recorded for lateral structure devices without ohmic contact (back to back Schottky diodes), 12.4 kV at 300μm distance.