Determination of residual stress in PZT films produced by laser ablation with X-ray diffraction and Raman spectroscopy

The stresses in lead zirconate titanate (PZT) films, produced by pulsed laser deposition with different ratios Zr/Ti, 92/8, 65/35 and 55/45, was studied using Raman spectra and X-ray diffraction techniques. Based on lattice parameters and the elastic constants of PZT the films stresses were estimated from XRD measurements using the calculated d-spacing in the stressed and unstressed states. The results revealed the presence of compressive stress in PZT with composition 55/45 and tensile stress in the others. On the other hand, analysing the Raman phonon frequency in the A1(TO3) and E(LO3) vibration modes and taking into account the phonon frequency under zero stress and the stress under which the phonon frequency becomes zero the stress in these films was estimated. The residual stresses extracted from the A1(TO3) mode are consistent with those extracted from the E(LO3) mode and with those measured by X-ray diffraction technique.