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

Abstract

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.