Thickness Determination of Thin Polycrystalline Films by Grazing Incidence X-Ray Diffraction

The thickness measurement based on absorption of X-rays in thin films has been tested on a polycrystalline titanium nitride films deposited on a tungsten carbide substrate. Intensities of three reflections from each material were measured for incidence angles of the primary beam ranging from 0.5° to 35°. After experimental correction for texture effects, data from the TiN film and the WC substrate were fitted by known functions using least squares routines. The substrate reflection intensities were found to be more suitable for determining the thickness of the overlaying thin film. The average thickness of TiN film (2.00± 0.17 µm) determined from the substrate reflections was in fair agreement with the average value obtained from optical microscopy (2.2± 0.8 µm). The thickness values determined from the TiN thin film reflections are very unreliable due to a high sensitivity of measurements to disturbing instrumental and sample effects at small angles.