Residual stress gradient analysis with GIXRD on ZrO2 thin films deposited by MOCVD

Zirconia (ZrO2) films were deposited by metal-organic chemical vapour deposition (MOCVD) on (1 0 0) Si single crystals using Zr(thd)4 precursor. The crystalline structure determined by X-ray diffraction (XRD) spectrum showed that the films exhibit the metastable tetragonal phase at room temperature. A method based on the pseudo-grazing incident X-ray diffraction (GIXRD) geometry was applied to study the residual stress gradient on the zirconia (ZrO2) films. By varying the X-ray beam penetration depth and the associated geometry angles, the residual stress profile can be described in detail. The residual stress profile revealed that tensile residual stress was present in the near-surface region and then it decreased rapidly as a function of depth; whereas, in the deeper regions, the films were under compressive stress. The origin of the residual stresses, which are assumed to consist of the film growth stress during the MOCVD process and film thermal stress during film cooling after deposition, is discussed.