Charge-sensitive deep level transient spectroscopy of boron-doped and gamma-irradiated mono- and polycrystalline diamond

Abstract

Electrically active defects in the boron-doped chemical-vapor deposited polycrystalline diamond films and single-crystal diamonds synthesized by high-pressure high-temperature technique were investigated. Isothermal charge-sensitive deep level transient spectroscopy was applied to study the density, activation energy and capture cross-section of native and boron-induced defects in diamond samples. It was shown that defects in the boron-doped polycrystalline diamond samples have a continuous energy spectrum with two peaks that correspond to discrete energy levels in the forbidden band of diamond, while in boron-doped homoepitaxial diamond films and single-crystal diamonds only one boron-induced deep level was displayed. The activation energy of the boron-induced levels decreases and the defect density increases with increasing boron concentration. It was found that gamma irradiation changes the parameters of boron-induced levels and increases the density of point defects with a continuous energy spectrum. The difference in activation energy of the boron-induced level into (1 1 1) and (1 0 0) faces of single-crystal diamond was observed as well.