Deep reactive ion etching (Deep-RIE) process for fabrication of ordered structural metal oxide thin films by the liquid phase infiltration method

Deep reactive ion etching (Deep-RIE) process was established for fabrication of highly nano-ordered metal oxide thin films such as TiO2, ZrO2, SnO2 etc, by the liquid phase infiltration (LPI) method. Electron beam lithography (EBL) technique and Deep-RIE were adapted to fabricate the Si wafer coated with a positive resist ZEP520A. Etching gas of SF6 and C4F8 was used for Deep-RIE process. The flow rate and repeating time were optimized in order to obtain the straight shape on the sidewalls of the trench or pillar structure. We used polymethylmethacrylate (PMMA) and acetylcellulose as a replica films. The transcribed replica films are applied to the liquid phase deposition reaction. The film structure was completely reproduced from the original shape of the designed Si wafer. The optical interference on the fabricated metal oxide thin films was also observed using absolute reflective visible spectroscopy.