Process optimization and properties of lead zirconate titanate (PZT) films for piezoelectric micromachined ultrasonic transducers (pMUTs) for scanning probe devices will be presented. The goal of the work was a replacement of the tetragenic and mutagenic solvent and a decrease of time-consuming PZT 2-methoxy ethanol (2MOE) route. An alternative diol-based solution synthesis process was developed and "Design Of Experiment" (DOE) was used to achieve processing optimization for thick and crack free films. Tight parameter control allowed to develop a highly reproducible PZT diol process. The crystallization behaviour of crack-free PbZr0.53Ti0.47O3 films (1-5 mu m) with oriented perovskite structure was examined by X-ray diffraction and surface analysis using scanning electron microscopy. Piezoelectric and dielectric properties were examined. The effective transverse piezoelectric coefficient e(31,f) of sol-gel processed films was investigated for 4 mu m thick layers. Best properties were achieved with {1 0 0}-textured films, where a remanent e(31,f) value of -7.3 C/m(2) was measured for 4.1 mu m thick films.
Duncan Thomas Lindsay Alexander, Chih-Ying Hsu, Bernat Mundet, Jean-Marc Triscone