RF magnetron sputter deposition and electrical properties of La and Y doped SrTiO3 epitaxial films

Abstract

La and Y doped SrTiO3 (STO) thin films were grown on (100) oriented pure STO single crystal substrates by the RF magnetron sputter technique. The La/Y doped layer is intended for use as bottom electrode for epitaxial growth of various functional oxide films. The results showed that one of the crucial deposition parameters to achieve the epitaxial growth of La/Y doped STO films with a pure phase and good electrical conductivity was sputter power, which must exceed 120 W. The conductivity of the grown films increased with the increase in sputter power and the La0.1Sr0.9TiO3 (LSTO) films deposited at 200 W had the highest conductivity of 292 S/cm. This was ascribed to the increased percentage of Ti3+ ions in the sputtered films, which was confirmed by the X-ray photoelectron spectroscopy. LSTO films deposited at 130 W were (100) oriented but the increased sputter power promoted the growth of a second texture, i.e. (110). On the other hand, Y0.08Sr0.92TiO3 (YSTO) films were able to keep the unique (100) texture in the films deposited over a range of sputter powers up to 200 W, although the conductivity of YSTO was lower, which was 98.0 S/cm for the films sputtered at 200 W.