Processing and Characterization of PZT and PLZT Thick Films

Abstract

Ferroelectric thin and thick films are being considered for numerous applications including micro-electromechanical systems (MEMS), transducers and actuators. Processing of ferroelectric films in the thickness range of 1 to 100 microns have already been attempted by various research groups, but failed in most of the cases due to extensive cracking problems during firing. For the past two years, we have worked on this problem and developed a process to fabricate thick films of lead zirconate titanate (PZT) and lead lanthanum zirconate titanate (PLZT) ceramics that were crack free, low in porosity with good ferroelectric properties. In our approach, sub-micron size powders of PZT and PLZT were synthesized via gelation of the precursor solutions. PZT and PLZT powders were then mixed with the same precursor solutions and ball-milled. Thick films of PZT and PLZT in the range of 5 to 20 μm were deposited via spin-coating technique on platinized Si substrates. The films were sintered at temperatures between 775 to 800 °C. Film thickness and surface roughness were characterized using SEM and profilometer. The surface and cross-sectional areas of the films appear to be crack free and homogeneous. Ferroelectric properties of some of these films are reported here.