Stress Factors and Absolute Residual Stresses in Thin Films Determined by the Combination of Curvature and sin²ψ Methods

Abstract

A new method is presented which allows the determination of experimental stress factors in anisotropic thin films on the basis of static diffraction measurement. The method is based on the simultaneous characterization of macroscopic stress and elastic strain in thin film using substrate curvature and sin2ψ methods, respectively. The curvature of monocrystalline substrate with known mechanical properties is determined using rocking curve measurements on substrate symmetrical reflections. The experimental stress and strain values are used to calculate stress factors for the specific film as a function sample tilt angle and reflection measured. The approach represents a relatively simple recipe to determine residual stress magnitude in thin films on the absolute scale. The procedure is demonstrated on polycrystalline Cu thin film deposited on Si(100).