Solution Deposition of Ferroelectric Thin Films

Abstract

Solution deposition has been used by almost every electroceramic research-and-development organization throughout the world to evaluate thin films. Ferrite, high-temperature-superconductor, dielectric, and antireflection coatings are among the electroceramics for which solution deposition has had a significant impact. Lithium niobate, lithium tantalate, potassium niobate, lead scandium tantalate, lead magnesium niobate, and bismuth strontium tantalate are among the ferroelectric thin films processed by solution deposition. However, lead zir-conate titanate (PZT) thin films have received the most intensive study and will be emphasized in this article. Solution deposition facilitates stoichiometric control of complex mixed oxides better than other techniques such as sputter deposition and metalorganic chemical vapor deposition (MOCVD). Solution deposition is a fast, cost-efficient method to survey extensive ranges of film composition. Further it is a process compatible with many semiconductor-fabrication technologies, and it may be the deposition method of choice for applications that do not require conformal depositions and that have device dimensions of 2 μm or greater. Specific applications for which solution deposition is commercially viable include decoupling capacitors, uncooled pyroelectric infrared detectors, piezoelectric micromotors, and chemical microsensors based on surface-acoustic-wave technology. Reviews of some of the more fundamental aspects of solution-deposition processing may be found in the scientific literature.