The Quality Improvement of Yttrium Oxide Thin Films Grown at Low Temperature via the Third‐Generation Mist Chemical Vapor Deposition Using Oxygen‐Supporting Sources

Abstract

Yttrium oxide (Y2O3) thin films are deposited by the third‐generation mist chemical vapor deposition (CVD) system. To avoid high growth temperature, H2O and O2, as oxygen sources, are selected to support the fabrication process. The Y2O3 films are prepared under different oxygen‐source supporting conditions to obtain high‐quality thin films; the effects of H2O and O2 on the film properties are also investigated to confirm the formation processes of Y2O3 films fabricated by mist CVD. Y2O3 films with a deposition rate of 9.0 nm min−1, refractive index of 1.76, and dielectric constant ranging from 15 to 20 are obtained at 400 °C when H2O is used to support the fabrication. Thermogravimetry–differential thermal analysis of the yttrium precursor Y(C5H7O2)3·nH2O is conducted using air and air+H2O mist as carrier gas. The analysis confirms that H2O supporting can lower the growth temperature and improve the film quality by reducing the formation temperature of main products in the process of obtaining Y2O3. Moreover, the H2O and O2 used in the fabrication are in liquid and gas phases, respectively. Consequently, the supporting processes of H2O and O2 occur at different time and space inside the reactor, which results in different supporting effects.