Abstract
Tantalum thin films have been preferred in case of corrosion protection in the chemical industry of high temperature applications because of its long lifetime and low service costs. Residual stress could be generated during thin film elaboration and they influence the film use properties. So, the residual stress level should be correctly determined especially in the case of stress gradient. X-ray diffraction (XRD) stress analysis is a local, non-destructive, quantitative method to study thin films. In the case of stress gradient, pseudo-grazing incidence X-ray diffraction (GIXRD) should be used in order to evaluate the residual stress distribution. Based on bibliographic works, a modified method has been developed for GIXRD stress analysis with the calculation of geometric adapted real angles ?'. This method allows more practically the determination of near surface stress gradient in specific direction and we name it sin^2? ' method. The developed new technique was applied on three Tantalum thin film specimens with different thickness (from 0.55 to 2.55μm) obtained with CVD process. The technological limits have been studied with different crystalline families, different incident radiations (Cu and Cr) and different GIXRD conditions (variable incidences). Then, GIXRD has been carried out both in a and β phases and residual stress distribution has been obtained for each of phase with selected family plan. The obtained residual stress level and their distribution were quite comparable with those determined by other GIXRD methods.
