Formation of a conducting layer by high energy metal ion implantation into diamond

Abstract

A conducting layer of Al or Cu was formed under the surface of synthetic Ib diamond (100) by high-energy metal ion implantation of 1×10 15–2.8×10 17 ions cm −2 with ion energies of 3 MeV (Al) and 8 MeV (Cu). The distribution peaks of heavily implanted Al and Cu, investigated by secondary ion mass spectroscopy (SIMS), were approximately 1.3 and 2.2-μm deep from the diamond surfaces, respectively. The results agreed with simulation results of TRIM. The Raman line of implanted diamond surfaces was observed at approximately 1333 cm −1, though they were broad and slightly shifted from the diamond Raman peak. The diamond structure was clearly observed at the implanted surfaces by reflection high energy electron diffraction (RHEED) measurements. From these results, it was concluded that the surfaces of the implanted diamond were not totally damaged. The sheet resistance of the metal implanted layers measured by a four-probe method decreased with increasing the ion dose and reached a minimum value of approximately 170 Ω/□. By comparing this resistance value with that of a similarly implanted layer in a SiO 2 glass substrate, it was concluded that electrons were transported mainly through the implanted metal layer for high dose specimens, while electron transport via defects was dominant for low dose specimens.