Sputtered lead scandium tantalate thin films for dielectric bolometer modethermal detector arrays

This paper describes the deposition of thin film lead scandium tantalate (P b2ScTaO6) using a novel two target sputtering technique and reports on the effect of post-deposition annealing. The films are deposited on platinum-co ated silicon wafers at 300 degreesC and are annealed at a range of temperat ures up to 800 degreesC. Vacuum furnace and rapid thermal annealing (RTA) m ethods are compared. Materials are characterised by X-ray diffraction and s how that the as-deposited films form a weak pyrochlore phase which is trans formed to perovskite PST by annealing. At anneal temperatures of 750 degree sC and above superlattice ordering is observed. Compositional measurements using Energy Dispersive Spectroscopy show that Lead loss is more severe usi ng furnace annealing than RTA, and a combined RTA/furnace anneal method is proposed. The films demonstrate relaxer dielectric characteristics. Induced pyroelectric measurements have been made to assess the potential of this m aterial for ferroelectric microbridge thermal detectors.