Conductivity of boron-doped diamond at high electrical field

Abstract

Electrical properties of epitaxial boron-doped diamond layers are studied at high electric fields in a wide range of boron concentration. Current-voltage characteristics co-planar concentric disk ring electrodes devices were measured using transmission line pulsed (TLP) characterization technique. Finite element method shows the electric field between test structures with co-planar plane parallel electrodes, used in previous studies, and concentric disk ring electrodes are comparable for inner ring electrode with a large diameter. The threshold electric field for the observed sudden increase of current, attributed to impurity impact ionization and/or self-heating, decreases from 130 kV·cm−1 to 70 kV·cm−1 with the increasing boron concentration in the epitaxial diamond layer. The measured quasi-static current grows exponentially with the electric field for energy dissipated in the devices limited below 2 μJ.