A kinetic study of chemical vapor deposition of AlN/TiN composite film

Understanding the deposition mechanism of a multi-component material by chemical vapor deposition (CVD) will provide an essential guide for design of CVD reactor. Especially, it will play an important role in the control of uniformity of film thickness and composition. In this study, A1N/TiN nano-structured composite films were synthesized by atmospheric-pressure chemical vapor deposition (APCVD), using aluminum chloride (AlCl₄), titanium chloride (TiC1₄) and ammonia (NH₃) as reactant gases at 1123 K in a horizontal tubular reactor. A kinetic study indicated a mechanism that two kinds of growth species were synthesized independently from AlCl₄/NH₃ and TiCl4/NH₃ system, respectively, and there is no interaction between the aluminum and titanium system in the gas phase. Each single-component growth rate was governed by the diffusion of its growth species from the gas phase to the substrate. Considering 1) that the growth species of TiN is synthesized faster than that of AIN, and 2) that the diffusion coefficient of TiN growth species is larger than that of AIN, we proposed that a rotating disk type is a suitable reactor for this CVD system.