Characterization of growth species is a key issue in thin-film preparation processes like CVD (chemical vapor deposition). In this paper, a novel method to determine the surface reaction rate constant of growth species is proposed, consisting of experimental measurement of the growth rate profile on a micrometer-sized trench and theoretical analysis of the profile by a reaction and diffusion model. The method was successfully applied to an APCVD (atmospheric-pressure chemical vapor deposition) process to synthesize AlN from AlCl3 and NH3. An activation energy of 163 kJ/mol shows that the surface reaction rate constant was obtained in spite of the present condition of strong mass-transfer limitation of the overall growth rate by diffusion from the bulk stream to the growing surface.
