Effect of Cu⁺ion implantation on crystalline orientation in polycrystalline Cu investigated by Kr penetration measurements

A series of 7 polycrystalline Cu targets was bombarded with successively increased doses of 40 keV Cu+ ions. Afterwards a trace amount of 40 keV radioactive 85Kr+ was injected into each target. The penetration of the Kr in the targets was then investigated by sequential 5 keV Ar+ ion sputtering and radioactivity counting. The results reveal that the penetration of the Kr increases systematically with dose of Cu prebombardment. This implies an enhanced probability of channelling due to a crystallographic reorientation of material in the surface layers. This finding corroborates X-ray diffractometer measurements which show an increase with dose of material with a <110> orientation perpendicular to the surface.