Preparation of BST ferroelectric thin films by pulsed laser deposition for infrared sensor

Abstract

Barium strontium titanate (Ba1-xSrxTiO3) shows great potential in optical device applications, especially in infrared uncooled focal plane arrays (UFPAs) fabrication. In this paper, Ba0.5Sr0.5TiO3 ferroelectric thin films were successfully deposited on different substrates by pulsed laser deposition (PLD) with an aim to fabricate dielectric bolometer type infrared (IR) sensor. The microstructure, crystalline characterization and surface morphology of the film were studied by XRD pattern and Atomic Force Microscope (AFM). The fabricated thin films show a similar perovskite structure, have evenly distributed grains and dense, crack-free surface. The dielectric properties and ferroelectric properties of the films are also studied after deposition of the top Pt electrodes. Results show that the film has fine dielectric and ferroelectric properties and could be used for infrared sensor fabrication. Buffer layer effect on film properties is also discussed. The use of different buffer layers could strongly influence the film performance. As in optical device applications, the buffer layer effect should be considered in film fabrication.