Electrical properties of epitaxial SrTiO3 tunnel barriers on (001) Pt/SrTiO3 substrates

Abstract

Coherent, epitaxial Pt films with root-mean-square surface roughness values of less than one unit cell were grown on (001) SrTiO3 substrates by dc sputtering. These Pt films served as bottom electrodes for epitaxial SrTiO3 tunnel barriers grown by rf magnetron sputtering. The SrTiO3 barriers were free of pinholes and showed mean surface roughness values of less than one unit cell. Barriers with a thickness of 4.5 nm showed excellent insulating properties and nonlinear current-voltage characteristics. At high bias fields, a reproducible hysteresis and deviation from the ideal tunneling behavior were observed.