Thickness determination of thin polycrystalline film by grazing incidence X-ray diffraction

Thickness measurement based on the absorption of X-rays in thin films has been tested on polycrystalline titanium nitride film deposited on a tungsten carbide substrate. The intensity of three reflections from each material was 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 intensity was 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 high sensitivity of the measurements to disturbing instrumental and sample effects at small angles.