Oxidation study of Co/Cu multilayers by resonant X-ray reflectivity

The outer oxide layer of magnetron-sputtered Co/Cu multilayers has been stu died by means of resonant and classical X-ray reflectometry. The variation of the oxide layer thickness has been monitored versus the upper-Co layer t hickness. The surface oxidation seems to stop at the Co/Cu interface and he nce no Cu oxide is produced. The contact potential at the Co/Cu interface m ay be at the basis of this effect. In addition, the dependence of the oxide layer roughness with its thickness has been studied, varying the roughness inversely to the oxide layer thickness, something which results comprehens ible on the basis of the low temperature oxidation process, (C) 1998 Elsevi er Science Ltd. All rights reserved.