A Study Of The Doping Process In Diamond By Boron Implantation

Abstract

Type IIa diamond crystals were implanted with boron ions with or without prior carbon ion implantation. The samples were kept at liquid nitrogen temperature during both implantation steps. A strong near-edge optical absorption band appeared after implantation, and partially recovered during annealing at 800 °C. For the highest B implantation fluence, optical absorption peaks at 2800 to 3000 cm-1 were observed that were in the same vicinity as the absorption peaks attributed to substitutional boron atoms in natural p-type diamond. Electrical measurements for three of the samples demonstrated well-defined activation energies that could be associated with hopping conduction and/or activation of B dopant atoms. This work shows that p-type doping in diamond by boron ion implantation is feasible, using a suitable combination of low temperature implantation and subsequent annealing.