Measurement of elastic modulus and residual stress of individual layers for composite films by resonant frequency of MEMS structures

This paper presents a direct and simple method to characterize the elastic modulus and residual stress of individual layers for composite films by measuring the resonant frequency. The structure is composed of the composite fixed-fixed beam. A model is developed to describe analytically elastic modulus and residual stress as a function of the resonant frequency of multi-layered fixed-fixed beams with different lengths and widths. FEM simulations are firstly implemented to validate the accuracy of the relationship between resonant frequency and mechanical properties. Experiments are then carried out by measuring the fundamental frequencies of the bilayer fixed-fixed beams with different lengths to extract the materials´ properties.