High-temperature Schottky diodes with thin-film diamond base

Abstract

High-temperature (500-580 degrees C) current-voltage (I-V) characteristics of gold contacts to boron-doped homoepitaxial diamond films prepared using a plasma-enhanced chemical vapor deposition (CVD) method are described. Schottky diodes were formed using gold contacts to chemically cleaned boron-doped homoepitaxial diamond films. These devices incorporate ohmic contacts formed by annealing Au(70 nm)/Ti(10 nm) layers in air at 580 degrees C. The experiments with homoepitaxial diamond films show that the leakage current density increases with the contact area. This implies that a nonuniform current distribution exists across the diode, presumably due to crystallographic defects in the diamond film. As a result, Au contacts with an area >1 mm/sup 2/ are essentially ohmic and can be used to form back contacts to Schottky diodes. Schottky diodes fabricated in this matter also show rectifying I-V characteristics in the 25-580 degrees C temperature range.