Doping of diamond by coimplantation of carbon and boron

Abstract

We have implanted boron ions into insulating natural diamonds which were predamaged by carbon ion implantation in order to enhance the doping efficiency. All implantations were performed at liquid-nitrogen temperature. Subsequent rapid thermal annealing at 1100 °C produced strong new optical absorption bands near 1060 cm−1, and a sharp absorption at 2962 cm−1 (0.37 eV) which is close to that attributed to substitutional boron in type IIB diamond. We obtained resistivity of the order of 100 Ω cm and carrier activation energy of 0.1 eV for a sample implanted with 2×1015 C and 3×1014 B per cm2, indicating a high substitutional fraction of boron atoms.