Scavenging of oxygen from SrTiO$_3$ by metals and its implications for oxide thin film deposition

SrTiO$_3$ is a widely used substrate for the growth of other functional oxide thin films. However, SrTiO$_3$ loses oxygen very easily during oxide thin film deposition even under relatively high oxygen pressures. In some cases, there will be an interfacial layer of oxygen-deficient SrTiO$_3$ formed at the interface with the deposited oxide film, depending on the metals present in the film. By depositing a variety of metals layer by layer and measuring the evolution of the core level spectra of both the deposited metal and SrTiO$_3$ using x-ray photoelectron spectroscopy, we show that there are three distinct types of behavior that occur for thin metal films on SrTiO$_3$. We discuss the implications of these types of behavior for the growth of complex oxide thin films on SrTiO$_3$, and which oxide thin films are expected to produce an interfacial oxygen-deficient layer depending on their elemental constituents.