Reducing the Gold Film Residual Stress by Using the Crystalline Piezoelectric Property in Piezoelectric/Au Thin Films

This work proposes a successful and novel method to significantly reduce the residual stresses of a 40 nanometer gold film in piezoelectric/Au thin films to improve the quality and mechanical properties of Au film. The gold film with 40 nm thickness is deposited on piezoelectric by means of diode sputtering system. Sample phases were examined using (XRD) analysis and the film residual stress is measured by the X-ray diffraction method. The numerical value of residual stress, has been obtained as 4.88±4.54 (MPa). Afterward, the 10 (kHz) frequencies with 12 volt amplitude were applied to the piezoelectric as substrate during 20 minutes. Subsequently, the residual stress values, was reduced to 2.68±1.63 (MPa). As a consequence, we were able to reduce the gold film residual stress through a new method, using the crystalline piezoelectric property. To obtain any information about structural changes in the film, X-ray diffraction measurements were performed. At the end of this article, the reasons for stress reduction that is related to the changes in full width-half maximum (FWHM), crystal aggregation, d-spacing and grain sizes factors of thin films has been investigated.