Measurement of Poisson's Ratio of a Thin Film on a Substrate by Combining X-Ray Diffraction with in situ Substrate Bending

A method to determine Poisson's ratio of a crystalline thin film on a substrate without sophisticated equipment and/or specimens is presented. The method is based on the combining x-ray diffraction and in situ substrate bending and the three components of the induced strains were measured by x-ray diffraction experiments using the well-known sin(2) psi method. The method allows one to extract the Poisson's ratio of the unpatterned thin films on substrates in a simple way and with a good precision. As an example, Poisson's ratio of a sputter-deposited copper film on a low-carbon steel substrate was measured.