Remarkable p-type activation of heavily doped diamond accomplished by boron ion implantation at room temperature and subsequent annealing at relatively low temperatures of 1150 and 1300 °C

Abstract

Highly efficient impurity doping in diamond by ion implantation has been a crucial issue in the field of semiconductor fabrication for several decades. We investigated the electrical properties of heavily B-doped type IIa diamond introduced by ion implantation at room temperature with a shallow and flat impurity concentration of 3.6 × 1019 cm−3 (∼200 ppm) from the surface to ∼130 nm depth, followed by thermal annealing at 1150 and 1300 °C. The activation of the implanted acceptor B was a maximum of 80% for the sample into which B ions were implanted at room temperature followed by 1150 °C annealing. The hole concentration and Hall mobility at room temperature were realized to be higher than 1 × 1014 cm−3 and 110 cm2 V−1 s−1, respectively. We confirmed p-type conductivity and typical activation energy of acceptor B at wide temperatures from −100 to 800 °C for the prepared samples. It was consequently revealed from this study that at least room temperature B-implantation followed by above 1150 °C annealing is sufficiently effective for the electrical activation of B doped in high quality diamond.