Exceptionally high voltage Schottky diamond diodes and low boron doping

Abstract

Exceptionally pure epitaxial diamond layers have been grown by microwave plasma chemical vapour deposition, which have low boron doping, from 5 × 1014 to 1 × 1016 cm−3, and the compensating n-type impurities are the lowest reported for any semiconducting diamond, <3 × 1013 cm−3. The hydrogen impurities that bind with the boron making them electrically inactive can be significantly reduced by baking the diamond to >700 °C for ∼1 s in air. Schottky diodes made on these epitaxial diamond films have breakdown voltages >6 kV, twelve times the highest breakdown voltage reported for any diamond diode and higher than any other semiconductor Schottky diode.