Properties and decomposition behaviors of reactively sputtered Pt(O) electrode materials

Abstract

The possibility that oxygen-containing Pt might be superior to conventional Pt as an electrode for high-epsilon (HE) and ferroelectric (FE) perovskites has led to renewed interest in the family of Pt(O) materials. Here we report on the properties and decomposition behaviors of reactively sputtered Pt(O)-PtOx electrode materials having x in the range 0 to approx. 1.4. Phases of Pt(O) identified included 〈111〉-textured cubic Pt (x < 0.2), tetragonal PtO (x approx. 1), and amorphous platinum oxide a-PtOx (x approx. 1.4). Film texture, morphology, resistivity, adhesion, and oxygen content were examined before and after annealing in O2 and N2 at temperatures approximating those of HE/FE deposition and processing (400 - 650°C). After annealing at 650°C for 5 min, all Pt(O) films lost oxygen and showed growth in metallic Pt phases whose orientations were often 〈200〉 or 〈220〉 rather than the 〈111〉 orientation typically produced by physical vapor deposition of the pure metal. Pt(O) films having a PtO-like structure typically showed only surface oxygen loss, with close to original oxygen levels left in the film bulk, suggesting that the oxygen in these films may be retained long enough to have a beneficial effect on HE/FE layers at later stages in processing.