Excimer Laser Annealing of Diamonds Implanted with Light Ions

In this paper the results of studies on annealing/graphitization/ablation processes induced in ion-implanted diamond layers by nanosecond pulse irradiation with KrF excimer laser (lambda=248 nm, tau=15 ns) are reported. The deeply buried damaged layers in diamond single crystals are produced by implantation with hydrogen, deuterium, and helium ions of 350 keV energy. It is shown that the non-linear depth distribution of radiation defects is a factor which strongly influences the character of laser-induced processes in the ion-implanted layers. Particularly, the annealing/graphitization behavior is found to be very different for irradiation conditions when a laser beam is incident on the ion-implanted surface with low defect density or, passing through diamond, onto the buried layer with high defect density. In the latter case, the annealing of radiation damage is much more efficient and graphitization in the deeply buried layers is inhibited. Based on white-light-interferometry examination of laserirradiated surface (with sub-nanometer resolution) and optical transmission in laser spots, peculiarities of laser annealing and graphitization in diamonds implanted to different doses are demonstrated and discussed.