Preparation of BST ferroelectric thin film by pulsed laser ablation for dielectric bolometers

摘要

Ferroelectric Ba{sub}0.75Sr{sub}0.25TiO{sub}3 (BST) thin film has been prepared for the development of a new-type dielectric bolometer using its temperature dependence of dielectric constant around the Curie temperature (T{sub}c). Pulsed laser deposition method has been employed to deposit BST films on a Pt/Ti/NSG(nondoped silicon glass)/SiN/SiO/Si(1 0 0) substrate. For a better understanding of how to obtain BST thin films with a high-and-sharp dielectric peak around the T{sub}c, X-ray diffraction, atomic force microscopy, D-E hysteresis and C-T characteristics were measured. It was found that the primary factors determining the dielectric behaviors of BST films are grain size and film thickness. BST films with thickness down to 0.6μm prepared at a substrate temperature of more than 550℃ showed some potential, and the crack-free 1μ m-thick highly oriented BST films with some degree of epitaxy can be a good candidate for such ferroelectric microbolometer application.