Stress analysis of elastically anisotropic bilayer structures

Abstract

In this paper, a newly developed model for analyzing stresses and curvatures in elastically anisotropic bilayer structures is presented. This model can be applied to bilayer structures composed of a single thin film that is deposited or grows on an elastically anisotropic substrate. The thin-film materials considered can be either elastically isotropic or anisotropic. According to this model, the Young’s modulus, Poisson’s ratio, and thermal-expansion coefficient of any given thin film cannot be determined independently by simply using a single elastically anisotropic substrate in a stress measurement without making additional assumptions. By using our model and with reasonable assumptions, more reasonable values of the mechanical constants and thermal-expansion coefficient of the aluminum thin film have been recalculated from the results of Janda [Thin Solid Films 112, 219 (1984)].