Chemical deposition of silica-based thin films under supercritical carbon dioxide atmosphere using tetraethylorthosilicate precursor with oxidizing agents

摘要

Supercritical fluid deposition (SCFD) of SiO₂-based films was proposed using TEOS precursor with oxidizing agents, for the purpose of low-temperature film deposition. The film deposition was performed in a batch-type closed chamber filled with supercritical carbon dioxide (CO₂) fluid. The SiO₂-based films were deposited on aluminum electrodes coated on silicon wafers (Al/Si) at the substrate temperature above 150°C. Oxidizing agents such as O₂ gas and aqueous H₂O₂ solution promoted the removal of C₂H₅OH byproduct and the formation of strong Si–O network, whereas it also promoted the homogeneous nucleation of granular precipitation and the H₂O adsorption in/on the resulting films. The processing temperature of the SCFD was significantly lower than those by thermal CVD and comparable or higher than those by plasma-enhanced CVD, although the resulting films obtained exhibited relatively large dielectric loss which depends on the presence of C₂H₅OH and H₂O byproducts.