Microwave Hydrothermal Growth of Thick Epitaxial Lead Zirconate Titanate Films

Epitaxial thin and thick lead zirconate titanate (PZT) films with the composition of PbZr0.7Ti0.3O3 were grown onto single-crystal SrTiO3 (100), (111), and (110) substrates using both microwave and conventional hydrothermal methods at 90–180°C from amorphous Zr-Ti hydrous oxide and lead acetate precursors. Different bases, such as KOH, NaOH, and tetramethylammonium hydroxide pentahydrate (TMAH) were used to study the effect of mineralizer type on the film quality and morphology. The impact of substrate surface modification on PZT nucleation and film growth was examined through chemical etching or pre-coating the substrate with a RF-sputtered thin PZT layer. Thick PZT film (~27 µm in thickness) was successfully synthesized by periodic replenishment of the reaction nutrient. Moreover, according to the collected kinetic data for microwave hydrothermal reactions, a microwave continuous-flow reactor operating at ≈ 300°C may be used to grow PZT films with the thickness of the order of 1 mm.