Annealing Induced Ordering of SrTiO₃ Thin Films Deposited by Laser Ablation Over Si Substrates

Abstract

Strontium titanate thin films have been prepared at different oxygen pressures and with different post deposition annealing treatments. The films were deposited by laser ablation at room temperature on Si(001) substrates with a silica buffer layer. The as-deposited films are amorphous with smooth and uniform surface. As the annealing temperature increase they become more crystalline, presenting a cubic SrTiO₃ phase. The infrared characterization show that the silica layer also grows due to the annealing. The characteristics of this SrTiO₃ crystalline depend on the oxygen partial pressure. At low oxygen pressures the annealed films are polycrystalline. As the oxygen pressure increase the films become more textured so that at longer enough annealing times the films become (200) oriented. The results are discussed in terms of atomic diffusion in the films.

Keywords:

• SrTiO₃
• annealing
• infrared spectroscopy
• modeling