High-Voltage Schottky Diodes on Boron-Doped Diamond Epitaxial Films

Abstract
High-voltage Schottky diodes have been fabricated on diamond epitaxial films with the structure: metal/undoped diamond/p+-type diamond. The films were epitaxially grown on synthesized single-crystal diamonds (100) by microwave plasma-assisted chemical vapor deposition (CVD) using H2 and CH4. B2H6 was used at B2H6/CH4=167 ppm for p+ diamond. Al Schottky electrodes and Ti ohmic electrodes were formed by an e-beam evaporation method and a thermal evaporation method, respectively. The forward current was independent of temperature because of the Fermi degeneracy in p+-type diamond. These diodes had a breakdown voltage of 520 V.