Deposition of Yb2O3 buffer films using H2O vapor by MOCVD method

Yb2O3 films were successfully deposited on (1 0 0) SrTiO3 (STO) single crystal substrates and on a cube-textured Ni–5at%W by MOCVD (metal organic chemical vapor deposition) method. H2O vapor was used as an oxidant in order to avoid the oxidation of Ni substrate. The working pressure, Ar flow rate and H2O vapor flow rate were 10 Torr, 600 sccm and 700 sccm, respectively. Epitaxial Yb2O3 (4 0 0) films were deposited on STO substrates at high temperatures above 950 °C, while small Yb2O3 (2 2 2) peak from XRD was detected below 920 °C. The AFM surface roughness of Yb2O3 film grown on STO was in the range of 10 nm for the film deposited at 950 °C with a H2O vapor partial pressure of 5.5 Torr and deposition time of 5 min. For cube-textured Ni–5at%W substrate, both Yb2O3 (2 2 2) and Yb2O3 (4 0 0) textures were grown at deposition temperatures above 850 °C. The Δϕ values of Yb2O3/STO were in the range of 2–3°, while Yb2O3/Ni–5at%W were in the range of 8–10.5.