Substitutional phosphorus doping of diamond by ion implantation

We have studied the lattice sites of ion-implanted radioactive 33P in natural IIa diamond using the emission channeling technique. 33P ions were implanted at room temperature with 30 keV and a rather low dose of 1011 cm−2 and the implanted samples were annealed in vacuum to 1200 °C. From the channeling effects of the emitted β− particles measured for all principal axial directions we obtain a fraction of 70±10% of substitutional P, a vanishing fraction on tetrahedral interstitial sites and a 30% random fraction. Possible displacements of the P atoms from ideal substitutional sites must be below 0.2 A. This demonstrates that P is a substitutional impurity in diamond and efficient substitutional P doping of diamond can be accomplished by a conventional implantation and annealing procedure if low implantation doses are chosen.