Abstract
In this study, the effective X-ray elastic constant (EXEC) can be obtained by combining two nondestructive methods: laser curvature and cos2αsin2ψ grazing incident X-ray diffraction (cos2αsin2ψXRD) techniques, which was used for the calculation of stress gradient in the thin films. TiN and ZrN thin films were selected as the model systems for the measurement of EXECs and stress gradients. Using cos2αsin2ψXRD at different incident angles on the same specimen, the average strains in the different diffraction volumes were obtained. Under the assumption that EXEC did not change significantly with different penetration depth, the average residual stress in different diffraction volume could be calculated. Then, the a layer-by-layer method was used to reduce the attenuation effect on X-ray stress information, and thus the more specific depth profile of the residual stress in the thin films could be established. The results of residual stress gradient are verified by comparing the average stress of the thin film determined by laser curvature method and the total stress from summarizing the layer stresses measured by XRD. The proposed method can reduce the uncertainties of individually measuring elastic constants and residual stress gradient by different methods, and enhance the efficiency of measuring the in-depth residual stress distribution in the thin films.