Thermal and Elastic Properties of Thin Films

Francisco C. Marques

Coefficient of thermal expansion, Young´s modulus, Poisson´s ratio, stress, hardness.

Optical, electronical and structural properties of thin films have been largely reported on literature. On the other hand, thermal properties have received little attention. Here we adopted two different techniques to determine thermal and elastic constants of thin films. The first was the bending beam technique, based on a deflection of a laser beam, used to determine the radius of curvature of the film/substrate composite, allowing extracting the stress of thin films. By making these measurements in substrates with different coefficient of thermal expansion we can also obtain a mixed elastic constant (biaxial modulus) involving a combination of the Young´s modulus and the Poisson´s ratio. Combining these results with a second technique, i.e., nanoindentationmeasurements, we demonstrate that one can obtaina total of 5 different thermal and elastic properties of thin films: stress, hardness, coefficient of thermal expansion, Young´s modulus and Poisson´s ratio. The procedure was used to obtain these parameters of hydrogenated diamond-like carbon (DLC) thin films.

10.22161/ijaers/3.11.15