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(ZrₓTi₿₋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 (d₃₃,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 d₃₃,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.