Role of Incident Angle and Geometry on XRD of Thin Films: Evaluation with Parallel Beam Configuration

Bayazıt T.

7th International Harran Congress on Innovative Approaches in Scientific Research, Şanlıurfa, Türkiye, 19 - 21 Ekim 2025, ss.1-3, (Tam Metin Bildiri)

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Basıldığı Şehir: Şanlıurfa
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.1-3
  • Recep Tayyip Erdoğan Üniversitesi Adresli: Evet

Özet

In this study, the effect of incident angle on the X-ray diffraction (XRD) characterization of thin films was systematically investigated using parallel beam (PB) geometry. This configuration was chosen to minimize errors from surface roughness, transparency, and specimen height misalignment, which often compromise the accuracy of thin film measurements. Various films prepared on different substrates under different processing conditions were examined separately. For each, XRD measurements were performed at incident angles ranging from 5° to 0.3°, allowing for an assessment of how the grating and PB geometries affect the diffraction signal.

The diffraction patterns were analyzed with respect to intensity, peak profile, and background. Particular attention was given to peak positions, full width at half maximum (FWHM), and relative intensities, which are key indicators of crystalline and microstructure. In addition, crystallite size (D), lattice strain (ε), and dislocation density (δ) were extracted from the data, providing further insight into structural quality.

The results showed that incident angle strongly affects measurement reliability: at higher angles, diffraction patterns were dominated by reflections from the substrate, reducing accuracy. At lower angles, the detected signal arose mainly from the film itself, allowing more precise determination of crystal structure and microstructural parameters.

This systematic evaluation of films confirms that optimizing incident angle is essential for obtaining consistent and reproducible XRD data in PB geometry. Overall, the findings highlight the critical role of measurement geometry in thin film diffraction and provide practical guidance for researchers seeking accurate structural and microstructural characterization of complex thin film systems.

Keywords: XRD, PB geometry, incident angle, thin film, microstructural analysis