Structural properties of sulfur-implanted diamond single crystals

The lattice location of sulfur implanted into diamond single crystals has been investigated using particle induced X-ray emission and ion channeling. Sulfur atoms were implanted into high-quality undoped homoepitaxial diamond (100) film grown by microwave plasma assisted chemical vapor deposition onto high-temperature and high-pressure synthetic Ib diamond (100) substrates, as well as into Ib diamond substrates directly, at 400°C up to the concentration of 1×10 ²⁰/cm³. They were annealed at 800°C in vacuum for 100 min after the implantation. Sulfur dopant was found to occupy preferentially substitutional sites in the host lattice. The possible maximum displacement of sulfur dopant was 0.14 A from ⟨001⟩ axis, and 0.07 A from ⟨011⟩ axis. The substitutional fraction of sulfur was 0.5 and 0.7 along ⟨001⟩ and along ⟨011⟩ direction, respectively. The depth profile of sulfur distribution measured by SIMS coincides with that of simulated vacancy depth profile associated with the sulfur implantation, rather than expected dopant distribution. These results suggest the redistribution of sulfur, and possible sulfur-residual damage (vacancy) coupling in the diamond crystal after the implantation