Preparation and Characterization of Thick Piezoelectric Films on Alumina Substrates

Abstract

In the near future piezoelectric appplications in micro-devices or in high frequency sensors will require piezoceramic films with thickness up to 100 µm [1–2]. Most piezoelectric film research has been on thin film technologies but more recently studies on thick films have been increasing [3–4]. A typical piezoelectric thick film is a structure with an alumina substrate (or metallic one), a screen printed Pt bottom electrode, a screen-printed piezoelectric film and a top Ag or Pt electrode. Pt ink is inert during PZT sintering but is much more expensive than the Ag/Pd ink which was used in the present work. The high porosity of the PZT layers can be decreased by additions of glass phases in the inks but the piezoelectric and electrical properties are often degraded [5]. VECHEMBRE et al. [4] has obtained well densified PZT layers (14 µm), prepared by a double print method, with a piezoelectric constant d₃₃ = 80 pC/N and a dielectric constant ε_r = 1040.