Polymer-based route to ferroelectric lead strontium titanate thin films



Ceramic films with high values of ferroelectricity, piezoelectricity, and dielectricity with perovskite structure, like lead zirconate titanate (PZT, PbZrxTi1-xO3), lead strontium titanate (PST, PbxSr1-xTiO3), and barium strontium titanate (BST, BaxSr1−xTiO3), are subjects of intensive research due to their use in sensors, energy harvesters, capacitors, and FeRAMs. Here a novel, simple way to produce micropatterned perovskite PST thin films on silicon substrates by a polymer-based direct UV-lithography process is presented. By acrylic acid modification of PST precursor sols it is possible to generate photosensitive metal organic PST precursor xerogel films by spin-coating and subsequently drying on silicon wafers. These films can be patterned by UV-lithography and developed with organic solvents. The resulting patterned gel films can be crystallized in air via rapid thermal annealing. The obtained perovskite thin ceramic films are polycrystalline and fine grained. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40901.