Microstructure and electrical conductivity of CaRuO3 thin films prepared by laser ablation

Abstract

CaRuO3 (CRO) thin films were prepared by laser ablation at substrate temperatures (Tsub) ranging from room temperature to 1073 K in a high vacuum (10-6 Pa) atmosphere and at oxygen pressures (Po2) of 0.013 to 130Pa. The effects of deposition conditions on the microstructure and electrical conductivity (σ) were investigated. Rectangular-shaped CRO island grains grew at 0.013Pa < Po2 < 130Pa and Tsub > 873 K. At Po2 = 0.13Pa and T sub = 973 K, as well as at Po2 = 13Pa and Tsub = 873 K, well-connected island grains were observed. While the composition of island grains was nearly stoichiometric independently of Tsub, the Ca fraction of film matrix increased with increasing Tsub. CRO thin films with σ less than 104 S.m-1 showed semiconducting behavior. At Tsub = 973 K and Po2 = 0.13 Pa, CRO thin films exhibited metallic conduction with the highest σ of 1.5 × 105 S.m-1 at room temperature. © 2008 The Japan Institute of Metals.