Nanoindentation load-displacement behavior of pure face centered cubic metal thin films on a hard substrate

Nanoindentaion tests have been performed on 0.1-3 mum pure aluminum, gold and platinum thin films deposited on sapphire single crystals. The load P-penetration depth h curves have been analyzed by three different kinds of equipment in order to investigate the deformation behavior. The plastic deformation of films is constrained by the hard substrate in the penetration depth range deeper than approximately 1/5 of film thickness for the case of using Berkovich indenter. The pop-in phenomenon often found for the case of aluminum films is considered to be caused by the natural oxide laver on the film surface, since decohesion of such thick films might not occur during the indentation testing. Equipment dependence of the derived results is found to be allowed within the limit of experimental error. (C) 2001 Elsevier Science B.V. All rights reserved.