Abstract: The Pb_0.4Sr_0.6TiO₃ (PST) thin films with the perovskite phase were fabricated successfully on ITO/glass substrates by the sol-gel method
with rapid thermal processing (RTP) above 500℃. The crystalline phase structures and the surface morphologies of the thin films were measured through XRD, SEM and AFM respectively. Results show that both the formation of the perovskite and
contents of the crystalline phase in this PST thin film are dependent on the preparing process and the activity of ions in the formation of the crystalline
phase. By RTP, high active ions obtained in the gel decomposition directly form the crystalline phase, and consequently, much more contents of the crystalline
phase can be obtained even at a relatively lower temperature. 14% more contents of crystalline phase appear in PST thin film at 600℃ by RTP than
by heat treatment at 600℃ for a long time. The lowest temperature of forming of the proveskite phase in sol-gel derived PST thin
film is approximately 500℃ by RTP, which is 50℃ lower than that by heat treatment for a long time. The surface morphology
of the thin film is related to the heat treatment processing. By RTP the surface morphology of the thin film keeps the original state, where the
actual smooth exhibits the noncrystalline thin film and the hill-like protuberance shows the well crystalline one. Due to etching under the
oxygen atmosphere at high temperature, the thin film calcined for a long time contributes the morphology with uniformly dispersed micro conical
cylinders all over the surface on the basis of the original smooth or hill-like surface state.

Key words: sol-gel, heat treatment, PST thin films, crystalline formation