X-ray diffraction measurement of residual stress in PZT thin films prepared by pulsed laser deposition

Abstract

Based on piezoelectric constitutive equations and Bragg law, we proposed an extended model, in which the piezoelectric coupling factor determined by the elastic, dielectric and piezoelectric constants is introduced, to evaluate the residual stress in ferroelectric thin film with X-ray diffraction (XRD). Pb(Zr 0.52Ti 0.48)O 3 thin films with thickness 0.05, 0.5, and 1.0 μm were grown on Pt/Ti/Si(0 0 1) by pulsed laser deposition (PLD) at the substrate temperature 650 °C and oxygen pressure 40 Pa. D500 goniometer and sin 2 ψ method were used to measure the residual stress in PZT thin films. The origin of residual stress was theoretically discussed from the epitaxial stress, intrinsic stress, thermal stress, and transformation stress. The results show that the theoretical results are closer to the experimental results evaluated by the extended model, and the residual compressive stress evaluated by the extended model is larger than that evaluated by the conventional model due to the consideration of the piezoelectric coupling effects.