Pyramid formation on a high index copper bicrystal during bombardment with10 keV argon and krypton ions

Pyramid formation on high index Cu (7 5 5) and Cu (13 3 2) crystal planes h as been studied during ion beam sputtering with 10 keV argon and krypton io ns, Thin sputter-deposited layers of Ti and redeposited layers of Cu-Ti-C o n the crystal planes were used to generate dense pyramid arrangements. Ion bombardment at normal incidence leads to a microtopography depending on the crystal orientation. Changing the ion beam direction, it is shown that the high index surface orientations and/or special angles of ion incidence are not decisive for pyramids to arise. Experimental evidence is provided that surfaces covered by pyramids result from simultaneous action of both ion b eam direction relative to the target lattice and surface covering with fore ign atoms. The formation of the observed microtopography shapes is related to anisotropic sputtering of the crystalline copper target. (C) 2000 Elsevi er Science B.V. All rights reserved.