A simple deflection-testing method to determine Poisson s ratio for MEMS applications

Abstract

A method to determine Poisson's ratio of thin films employing a simple experimental deflection test and a simulation program has been developed. According to the method, knowing Young's modulus and measuring the deflection at an arbitrary point on the thin film, the Poisson's ratio can be determined using any mechanical finite element analysis (FEA) program. Two examples are considered to test the method, with both yielding the same results. Due to the relative simplicity involved with this procedure, it is believed that the method can be used by MEMS researchers to determine Poisson's ratios of their own thin films of interest. In addition, in the case that Poisson's ratio is known and Young's modulus is unknown, the method may be applied to find the Young's modulus.