Compositional Dependence of the Young’s Modulus and Piezoelectric Coefficient of (110)-Oriented Pulsed Laser Deposited PZT Thin Films

In this contribution, we report on the compositional dependence of the mechanical and piezoelectric properties of Pb(Zr_xTi_1-x)O₃ (PZT) thin films fabricated by pulsed laser deposition (PLD). These films grow epitaxially on silicon with a (110) preferred orientation and have excellent piezoelectric properties, which make them outstanding candidates for application in microelectromechanical system devices. Vibrometric measurements on capacitors showed that the effective longitudinal piezoelectric coefficient (d_33,f) of 100-nm thick PZT films has a maximum value of 72 pm/V for a composition of x = 0.52. The Young´s modulus was determined by measuring the difference in the flexural resonance frequencies of cantilevers before and after the deposition of the PZT thin films. The compositional dependence of the Young´s modulus shows an increase in value for the Zr-rich compositions, which is in agreement with the trend observed in their bulk ceramic counterparts. From the obtained dielectric constant and d_33,f, we show that the calculated coupling coefficients of the PLD-PZT thin films have higher values for most of the compositions than their ceramic counterparts.