Preparation of BaTiO₃ thin films of micrometer range thickness by pulsed laser deposition on (001)LaAlO₃ substrates

Thick BaTiO3 (BTO) films of up to 2.5 μm thickness have been deposited on (001)LaAlO3 (LAO) substrates using pulsed laser deposition (PLD). The evolution of structural properties with film thickness was investigated by X-ray diffraction (XRD) analysis, Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). XRD and Raman analyses show that BTO films, with a thickness of up to 2.5 μm, are all c-oriented and epitaxially grown on LAO. No impurity (non-BTO) phase in the films has been detected. It is noted that the crystalline quality of the BTO films, as revealed by the narrowing of the full width at half maximum (FWHM) of the rocking curves, increases with film thickness. Moreover, SEM and AFM results demonstrate that large grain size and a rough surface are observed in thick films. On the basis of these results, it can be concluded that growing thick BTO films by PLD can produce improved crystalline qualities but decreased surface smoothness due to enhanced columnar grain growth.