Processing and properties of screen-printed lead zirconate titanate piezoelectric thick films on electroded silicon

The printing of lead zirconate titanate (PZT, Pb(Zr,Ti)O-3) piezoelectric thick films on silicon substrates is being studied for potential use as microactuators, microsensors, and micro.. transducers. A fundamental challenge in the fabrication of useful PZT thick-film devices on silicon is to sinter the PZT to high density at sufficiently low temperature to avoid mechanical or chemical degradation of the silicon substrate. The goal of the present study is to develop and implement suitable electrodes and PZT sintering aids that yield attractive piezoelectric properties for devices while minimizing reactions between the silicon, the bottom electrode, and the PZT thick film. A B2O3-Bi2O3-CdO sintering aid has been found to be superior to borosilicate glass, and the use of a gold/platinum bilayer bottom electrode has resulted in better thermal stability of the electrode/film structure. Films sintered at 900 degreesC for 1 h have relative permittivity of 970 (at 1 kHz), remnant polarization of 20 muC/cm(2), coercive field of 30 kV/cm, and weak-field piezoelectric coefficient d(33) of 110 pm/V.