Influence of post-deposition thermal annealing on the properties of pulsed laser deposited tungsten layers

Abstract

Crystalline tungsten oxide thin films are obtained by thermal oxidation of metallic W films, deposited on quartz substrates under vacuum conditions by the pulsed laser deposition (PLD) technique. The as-deposited tungsten films are annealed in air at various temperatures, viz. 673, 873 and 1073 K. X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and micro-Raman techniques are employed for the investigation of microstructural characterization of both as-deposited and annealed films. The influence of laser energy and duration of deposition on the microstructural, optical and electrical properties of the films are studied in detail. Among the films investigated, thicker tungsten films (having a thickness of ∼500 nm), deposited with laser fluence 4 J cm−2 for 45 min duration and annealed at 873 K, exhibit better physical properties and microstructural features compared to other films.