Low-resistivity SrRuO3 thin films formed on SiO2 substrates without buffer layer by RF magnetron sputtering

Abstract

Thin films of SrRuO3, which is a conductive oxide, have the potential for use as electrode layers in versatile electronic applications, particularly with perovskite structured dielectric and ferroelectric oxide thin films. Moreover, for practical device applications, it is important to develop the deposition process of low-resistivity SrRuO3 thin films on SiO2 substrates. Therefore, in this study, the growth and characteristics of SrRuO3 thin films deposited by radiofrequency magnetron sputtering on SiO2 substrates without a buffer layer were investigated. It was found that the oxygen flow ratio in the growth ambient, post-deposition annealing temperature, and post-deposition annealing time are key parameters in realizing high-quality SrRuO3 thin films. When SrRuO3 thin films were deposited with a gas flow ratio of Ar:O2 = 1:1.5 and subjected to post-deposition annealing in an oxygen ambient at 750 °C for 3 min, they exhibited an excellent resistivity of 148 μΩ-cm. This value is comparable to that of SrRuO3 thin films epitaxially grown on single-crystal SrTiO3 or LaAlO3 substrates.