Characterization of alkaline earth metals ruthenate thin films

SrRuO3 (SRO), BaRuO3 (BRO) and CaRuO3 (CRO) thin films prepared by laser ablation in a wide range of deposition conditions were investigated on the relationship between deposition conditions, phase formation, microstructure and electrical conductivity. The optimum conditions for preparing highly conductive thin films were investigated. SRO, CRO and BRO thin films were crystallized with pseudo-cubic SRO and CRO, and a 9R-type hexagonal BRO structure, respectively. SRO and BRO thin films were crystallized with fine grains, whereas rectangular-shaped island grains tended to grow on the CRO thin films. The electrical conductivity of SRO and BRO thin films increased with an increase in deposition temperature of substrate and an increase in oxygen pressure, meanwhile, in CRO thin films, only the CRO thin film with a continuous surface of connected grains exhibited metallic conduction. However, the electron conduction transition from semi-conducting behavior to metallic conduction occurred when σ of 104 S m−1 was reached independent of alkaline earth metal and microstructure. The optimum conditions were Tsub = 773 to 973 K and PO2=0.13PO2=0.13 to 13 Pa.