Microstructure of erbium oxide thin film on SUS316 substrate with Y₂O₃ or CeO₂ buffer layers formed by MOCVD method

Er₂O₃ has been known the best candidate material for insulating coating for liquid metal breeding blanket system. The formation of Er₂O₃ layer by MOCVD method can be succeeded on SUS316 substrate with CeO₂ and Y₂O₃ buffer layers (100 nm and 500 nm) fabricated by RF sputtering, and their microstructures have been confirmed by SEM, TEM and STEM. The surface morphology of their layers was smaller granular structure than the previous study without buffer layer. According to cross sectional TEM (X-TEM) observation, Er₂O₃, CeO₂/Y₂O₃ buffer, unknown layers and SUS substrate can be confirmed. CeO₂ buffer layer has a granular structure, while Y₂O₃ has a columnar structure. Er₂O₃ layer formed on each buffer layer had finer structure without buffer layer. It has been also detected that each element does not exist so much in each layer by diffusion during fabrication according to STEM-EDS and HAADF imaging.