Composition dependence of mechanical and piezoelectric properties of pulsed laser deposited Pb(Zr,Ti)O₃ thin films

In this contribution we present the compositional dependence of the longitudinal piezoelectric coefficient (d33,f), residual stress and Young's modulus of Pb(Zrx,Ti1-x)O3 (PZT) thin films. Pulsed laser deposition (PLD) was used to deposit epitaxial PZT thin films with a < 110 > preferred orientation on silicon cantilevers. By using PLD, excellent piezoelectric properties of the PZT were observed which makes it an exciting piezoelectric material for the development of actuators and highly sensitive sensors. Our investigation of the compositional distribution of the piezoelectric coefficient (d33,f) for 250 nm thick films shows a maximum value of 93 pm/V for x=0.52. The static deflection of the cantilevers, measured after the deposition of PZT thin films was used to determine the residual stress for various compositions. The observed trend in the residual stress of PZT thin films is attributed to the varying coefficient of thermal expansion for different compositions. The Young's modulus of the PZT thin films was determined by measuring the flexural resonance frequency of the cantilevers both before and after the deposition. The Young's modulus increases for the zirconium rich PZT compositions, which is in agreement with the trend observed in their bulk ceramic counterparts.