An Experimental Study of the Influence of Imperfections on the Buckling of Compressed Thin Films

M.-W. Moon, J.-W. Chung, K.-R. Lee, K. H. Oh, R. Wang, and A. G. Evans

The role of imperfections on the initiation and propagation of buckle drivendelaminations in compressed thin films has been demonstrated using experimentsperformed with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The wavelengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection wavelength. The findings have been rationalized in terms of theoretical results for the effect of imperfections on the energy release rate.