Evaluating diffusion barriers of defects in boron ion implanted diamond

Abstract

The potential of diamond for electronic materials can be realized by creating well-controlled p- or n-type doping profiles. p-type doping is achieved by ion implantation of boron followed by high temperature annealing to relax the lattice, reduce the defects and create active dopant sites by allowing diffusion of defects in the diamond crystal. It has been found that even after this diffusion the percentage of active dopant sites after high temperature annealing are only a small fraction of the total doping. We perform first principles density functional theory calculations and estimate the migration barrier energy (MBE) for diffusion of carbon vacancies, hydrogen, boron and their complexes in diamond including the boron‑carbon vacancy complex which was recently observed and predicted as a color center for qubit realization. These defects are commonly found after ion implantation of boron in diamond. Here, we use nudged elastic band (NEB) technique to estimate the MBE for these defects and use it to predict the corresponding annealing temperature. Our calculations correctly predict the MBE for carbon vacancy as compared to the available references in literature and extend the calculation to other defects predicted in ion implanted diamond. Our objective of evaluating the MBE is to predict the diffusion processes occurring during post-implantation annealing of diamond.