Processing of PZT piezoelectric thin films for microelectromechanical systems

Piezoelectric Pb(Zr/sub 0.52/Ti/sub 0.48/)O/sub 3/ (PZT) thin films for microelectromechanical systems (MEMS) were deposited on platinum coated silicon substrates by sol-gel processing using lead acetate trihydrate as the lead source. A thickness uniformity of better than 1% variation over 4" wafers was achieved. Auger depth profiling showed good compositional homogeneity through the film thickness, with some lead loss at the film surface. A PbO top layer on the top of PZT thin films gave improved properties. Grazing angle scanning XRD confirmed that the PbO top layer helped prevent the formation of a pyrochlore surface layer during crystallization. Work on reactive ion etching of the PZT thin films was also initiated. It was found that Cl/sub 2//CCl/sub 4/ mixtures could be used to etch PZT with an etching rate of 100/spl sim/150 /spl Aring//min, and HCFC-124 with a rate of 320 /spl Aring//min.