He+ ions were used to create layers containing a very low density of vacancies in diamonds. After this step, B+, P+ or C+ ions were implanted at a shallower depth under conditions where some of the implanted atoms were forced to diffuse into the first layer. By etching off the shallower layers, the initial, deeper layers were exposed. The electrical conduction in these layers was then studied. The C+-ions were used as a control. After this low-damage drive-in process, the C+ low-damage drive-in layer had the highest resistance and conducted by means of variable range hopping. In contrast. B+ low-damage drive-in and P+ low-damage drive-in layers could be prepared which conducted by means of the thermal activation of holes and electrons, respectively.

Doping of Diamond by the Diffusion of Interstitial Atoms into Layers Containing a Low Density of Vacancies. Prins, J.F.: Diamond and Related Materials, 1998, 7[2-5], 545-9