Nanoindentation measurement of Young’s modulus for compliant layers on stiffer substratesincluding the effect of Poisson’s ratios

Abstract

Finite element analysis (FEA) is used to investigate the effect of the Poisson’s ratios ofboth the overlayer and the substrate on the nanoindentation of an elastic two-phase systemwhere the elastic overlayer is more compliant than the underlying elastic substrate. A rigidspherical indenter is used as a probe. It is found that nanoindentation results maybe expressed analytically using a simple extension of the previously describedequation (Clifford and Seah 2006 Nanotechnology 17 5283). This simple functiondescribes the reduced modulus value measured using Oliver and Pharr’s method(1992 J. Mater. Res. 7 1564) for any modulus values or Poisson’s ratio values of the overlayerand substrate, overlayer thickness or indenter tip radius. This equation and the FEAbehind it are tested using experimental published data for the nanoindentation of asilicon dioxide layer on silicon.