This paper presents the results of nanoindentation experimental studies of the contact-induced deformation in Au and Ag thin films. The paper
examines the effects of film thickness and substrate deformation restraint on the mechanical properties of electron beam (e-beam) deposited Au
and Ag films. Following a brief description of film microstructure, surface topography, and contact-induced pile-up deformation, film mechanical
properties (hardness and Young’s modulus) were determined using nanoindentation techniques. The indentation size effects (ISE) observed in
films with different thicknesses were explained using a mechanism-based strain gradient (MSG) theory. The intrinsic film yield strengths and
hardnesses extracted from the MSG theory are shown to exhibit classical Hall–Petch dependence on the inverse square root of the average film
grain size. Displacement bursts were also found to occur in Ag films at indentation load levels of 100 N. These were attributed to the initial onset
of dislocation slip activity, when the shear stress exceeds the estimated theoretical shear strengths of the materials.