POISSONS RATIO MEASUREMENT IN TUNGSTEN THIN-FILMS COMBINING AN X-RAY DIFFRACTOMETER WITH IN-SITU TENSILE TESTER

A direct determination of the Poisson's ratio in 150 nm polycrystallin e tungsten thin films deposited by ion-beam sputtering on Duralumin su bstrates has been performed by combining x-ray diffraction measurement s with in situ traction on the sample. X-ray diffraction experiments u sing the sin (2) psi method have been done at LURE, the French synchro tron facility (Orsay, France) on a four-circle diffractometer. The met hod described in this letter allows us to extract in a simple way and with a good precision the Poisson's ratio of thin films on substrates from the evolution of the sin(2) psi curves as a function of applied s trains. In the case of tungsten thin film, the value obtained is close to the bulk material one. (C) 1998 American Institute of Physics. [S0 003-6951(98)00240-X].