Virgin (110) single crystals were implanted with 30keV 3He+ ions, to a dose of 5 x 1015/cm2, and were then annealed under air for 0.5h in a tube oven. The annealing behaviour was monitored by using positron-beam Doppler broadening, neutron depth-profiling and optical absorption techniques. It was concluded that, below 1000C, vacancy-like defects were stabilized by the implanted He atoms. Above this temperature, He could dissociate from these small defects and permit the formation of larger vacancy clusters.

Annealing Behaviour of Defects in Helium Implanted MgO. H.Schut, A. Van Veen, F.Labohm, A.V.Fedorov, E.A.C.Neeft, R.J.M.Konings: Nuclear Instruments and Methods in Physics Research B, 1999, 147[1-4], 212-5