Effect of ion fluence on the surface morphology of single crystal magnesium oxide implanted with xenon

Abstract

The surface morphology (001)-oriented single-crystal magnesium oxide (MgO) implanted with xenon ions has been examined using atomic force microscopy. It was found that at the lowest fluence used in this study (1.0 × 1014/cm2), a slight roughening of the (001) surface occurred. The magnitude of this roughening remained fairly constant with increases in fluence in the range 1.0 × 1014/cm2 to 3.0 × 1016/cm2. Implantation at fluences of ≥ 1.0 × 1017/cm2 caused significant surface roughening with the concomitant formation of micron-sized blisters. The appearance of some of these blisters resembles the rosette pattern that is also observed when the cleaved surfaces of MgO crystals are etched following indentation using a spherical indenter. This observation suggests that these blisters are formed by the growth of xenon inclusions, during implantation, by a dislocation loop punching mechanism.