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

Ferroelectric Ba0.75Sr0.25TiO3 (BST) thin film has been prepared for the de velopment of a new-type dielectric bolometer using its temperature dependen ce of dielectric constant around the Curie temperature (T-c). Pulsed laser deposition method has been employed to deposit BST films on a Pt/Ti/NSG(non doped silicon glass)/SiN/SiO/Si(100) substrate. For a better understanding of how to obtain BST thin films with a high-and-sharp dielectric peak aroun d the T-c, X-ray diffraction, atomic force microscopy, D-E hysteresis and C -T characteristics were measured. It was found that the primary factors det ermining the dielectric behaviors of BST films are grain size and film thic kness. BST films with thickness down to 0.6 mum prepared at a substrate tem perature of more than 550 degreesC showed some potential, and the crack-fre e I mum-thick highly oriented BST films with some degree of epitaxy can be a good candidate for such ferroelectric microbolometer application. (C) 200 0 Elsevier Science Ltd. All rights reserved.