Selective deposition of cobalt oxide thin films via H₂O-vapor-catalyzed reaction

In this study, we developed a method for realizing the selective deposition of CoO thin films using Co(hfac)₂ as a cobalt precursor and H₂O vapor as a catalyst gas. Deposition on an insulator substrate can be controlled by varying the H₂O flow rate. In order to study the gas-phase reaction, the concentration of generated particle was investigated as a function of the deposition temperature using an in-situ particle measurement system such as fourier transform infrared spectroscopy (FT-IR) to analyze the decomposition behavior of precursor and particle beam mass spectrometry (PBMS) to analyze the relationship between the precursor decomposition and the particle nucleation. Process temperature was controlled from 573 to 723 K with 50 K intervals. A gas cell was designed to analyze the decomposed precursor by FT-IR system, and its exhaust was connected with PBMS inlet to collect particles. Field-effect scanning electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS) measurements were carried out to determine the film properties and its effects of H₂O on catalytic reactions.