Oxygen stoichiometry in PdOx and PdOxPt electrode layers during processing of ferroelectric and high-epsilon perovskites
Abstract
High-epsilon (HE) and ferroelectric (FE) perovskites such as (Ba,Sr)TiO3 and SrBi2Ta2O9 are attracting substantial interest for use in dynamic random-access memory and nonvolatile memory. In this paper, we describe how an easily decomposable PdO bottom electrode layer may be used as a marker for possible HE/FE damage induced by exposure to reducing environments. Oxygen loss from PdO films with and without a HE/FE overlayer was monitored by in situ x-ray diffraction during heating in an inert ambient. Additional measurements were performed on PdO films in contact with Pt underlayers. A Pt underlayer was found to reduce the temperature of oxygen release from PdO, suggesting that it may be possible to custom-design PdO-based oxygen sources with specific oxygen release characteristics to resupply the HE/FE with oxygen lost during processing.