The effects of vacuum annealing and H-plasma exposure upon ion-implantation induced defects were investigated in high-quality chemical-vapor deposited material by means of cathodoluminescence measurements. Well-focussed 30keV Ga ions were implanted to doses ranging from 1 x 1012 to 1 x 1015/cm2. Free-exciton emission and N-V centers were observed at 235 and 575nm, respectively, in the room-temperature cathodoluminescence spectra of as-grown homoepitaxial chemical-vapor deposited samples. The former vanished completely after any implantation, while the latter were destroyed more extensively with increasing dose. Band-edge emissions at 235nm hardly recovered after any treatment. The cathodoluminescence peak at 575nm reappeared after 0.5h vacuum annealing at 900C, following a Ga dose of 1 x 1012/cm2, or after suitable H-plasma treatment at any Ga-ion dose. It was found that the band-edge emission signal was required in order to investigate beam damage to so-called high crystalline quality diamond. Removal of the damaged surface layer by plasma-etching was also considered with regard to recovery process, especially the 575nm peak at heavier ion doses.

Recovery Treatments for Ion-Induced Defects in High-Quality Homoepitaxial CVD Diamond. S.Endo, K.Kimura, M.Irie, C.L.Wang, T.Ito: Diamond and Related Materials, 2001, 10[3-7], 322-6