Thin/thick piezoelectric films by electrophoretic deposition

Abstract

Electrophoretic deposition (EPD) is a simple, rapid, and low cost method for producing conformal films on patterned electrodes. This paper covers the use of EPD for forming fully dense Lead Zirconate Titanate (PZT) films of twenty microns and less. The three main steps of this process as applied to PZT are covered: (1) formation of a charged suspension of the starting sub-micron PZT powder, (2) deposition of the powder particles on an electrode under the influence of a DC electric field, and (3) fluxing and constrained sintering of the resulting particulate deposit to form a dense continuous film. Using this process we have formed six to ten micron PZT films on an alumina substrate, sintered to fully density at 900°C. In a fourteen micron film we have achieved a piezoelectric d₃₃ coefficient of 140 picoCoulombs/Newton, and a dielectric constant of 1,000 with a loss tan δ of 0.045.