Realization of P-Type Conductive Layer on Type Iia CVD Diamond by B^+ Ion Implantation at Room Temperature Followed by 1150 and 1300℃ Annealing

We have investigated the electrical properties of heavily B-doped type IIa diamond introduced by ion implantation at room temperature with a flat impurity concentration of ～200 ppm, followed by thermal annealing at 1150 and 1300℃. We confirmed p-type conductivity and typical activation energy of acceptor B in diamond at wide temperatures range from 173 to 1073 K. The doping efficiency for the sample after the 1150℃ annealing was realized to be 78%, which is the best value ever reported. The Hall mobility around room temperature was realized to be higher than 100 cm^2/Vs. It is consequently revealed that at least room temperature B-implantation followed by above 1150℃ annealing is sufficiently effective for the electrical activation of B doped in high quality diamond.