Thickness Dependence of Piezoelectric Properties for PZT Thin Films with Regard to MEMS Applications

Abstract

In this work we report on the investigation of the piezoelectric and ferroelectric properties of Pb(Zr,Ti)O3 (PZT) thin films with a composition of 45% zirconium and 55% titanium prepared by chemical solution deposition (CSD) regarding the major properties required in MEMS applications. Therefore we have measured the polarization and the piezoelectric coefficient d 33 and strain using a high-resolution double beam laser interferometer. We found that d 33 alike the strain is nearly independent of the sample thickness. To estimate the lifetime of MEMS we stressed the samples by applying switching and non-switching voltage pulses. In the non-switching case, no change of the material properties was observed whereas the use of switching voltage pulses resulted in a strong decrease of the piezoelectric properties and the polarization. Here we found a linear behavior between the material properties in the fatigued state and the sample thickness.