Formation of Erbia-Yttria double layer fabricated by metal organic chemical vapor deposition process with changing oxygen flow rates

Er₂O₃ and Y₂O₃ are promising materials for advanced breeding blanket system of nuclear fusion reactor because they have high electrical resistivity and effective tritium permeation suppression. In this report, Er₂O₃ thin films were fabricated by metal organic chemical vapor deposition (MO-CVD) process with changing oxygen flow rates on the stainless steel 316 (SUS316) substrate with Y₂O₃ layer fabricated via radio frequency (RF)-sputtering. Samples were prepared with four conditions of oxygen rate, 0.08, 0.13, 0.25, 0.42 Pa∙m³/s (50, 75, 150 and 250 sccm, respectively) and only on Er₂O₃ / Y₂O₃–0.42 Pa∙m³/s sample was added thermal cycles. Four samples were observed with using X-ray diffraction (XRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Increasing oxygen flow rate during MO-CVD process increased the thickness of Er₂O₃ thin film and decreased columnar width and succeeded in fabricating Er₂O₃ thin film and dense microstructure on the SUS 316 substrate with Y₂O₃ layer.