Kinetic analysis of face-centered-cubic Ti1− x Al x N film deposition by chemical vapor deposition

Highlights: • We deposited metastable fcc-Ti_0.25Al_0.75N polycrystal using low-pressure CVD. • The film had a single phase oriented in the deposition direction. • Activation energy of fcc-TiAlN deposition was less than 10 kJ/mol around 800 °C. • TiAlN was formed by the combined deposition of TiN and AlN. • The deposition of fcc-TiAlN was limited by diffusion of precursors in the reactor. Metastable Al-rich face-centered-cubic (fcc) TiAlN polycrystals have attracted attention as coating materials. However, the mechanism of chemical vapor deposition (CVD) of TiAlN has yet to be clarified. In this study, we performed a kinetic analysis of fcc-TiAlN deposition by investigating its dependence on deposition temperature and the partial pressures of metal sources. We deposited metastable fcc-Ti_0.25Al_0.75N polycrystals of a single phase that oriented in the deposition direction from TiCl₄/AlCl₃/NH₃. The activation energy of TiAlN formation around 800 °C was less than 10 kJ/mol. TiAlN was deposited by a first-order reaction with different partial pressures of metal sources. TiAlN was formed by the combined deposition of TiN and AlN. The overall reaction rate constants for TiN and AlN and the mass transfer coefficients of the precursors TiCl₄ and AlCl₃ had similar values. Therefore, the deposition of fcc-TiAlN under the investigated experimental conditions was limited by precursor diffusion in the reactor.