Numerical simulation and mechanical properties of free-standing silver thin films

Abstract

Membrane deflection test is well studied to investigate the mechanical properties for polycrystalline metal thin films. Numerical simulations by ANSYS software of membranes with different bottom window sizes show the overestimation of elastic modulus while using the gauge width to calculate the elastic modulus. The second part of the work includes the fabrication and membrane deflection test of 0.5 µm and 1µm silver free standing thin films. Two methods to etch silicon nitride to release the silver membranes are performed by using inductively coupled plasma (ICP) etcher STS AOE (Advance oxide etcher) and by hot phosphoric acid etching. The mechanical behavior of silver free-standing thin films released by AOE and hot acid etching show a discrepancy. It may be contributed to the texture change due to heat treatment of silver thin film during hot phosphoric acid etching. Also shear localization is observed in the deformation process of silver thin film with hot phosphoric acid etching.