Peculiarities of damage in diamond irradiated by high energy ions

Abstract

High energy copper (63 MeV, 5 × 10 14 cm −2) and neon (26.7 MeV, 5 × 10 14 cm −2) implantation of diamond crystals results in a single EPR line similar to that of paramagnetic centers (PC) of amorphous regions (AR) produced by low energy implantation but having marked anisotropy and asymmetry. The PC symmetry is axial with the axis coinciding with the ion beam direction. It has been shown that the damage regions produced in diamond by high energy ion irradiation are tracklike regions, stretched along the irradiation direction. It has been established that the cross-section geometry of these regions depends on the primary ion beam orientation relative to the crystal axes: the tracklike regions have the C ∞-symmetry axis for the irradiation along the 〈111〉 direction and they have the C 4-symmetry axis for the irradiation along the 〈100〉 direction. It has been proposed that within the tracklike regions the tetrahedral atom coordination is being lost and some sort of quasi-one-dimensional long-range ordering appears. A weak magnetic ordering is also proposed to be characteristic of these regions.