In many thin film growth systems, the surface morphology develops via nucleation of two-dimensional clusters, their growth and coalescence. When desorption of surface adsorbate is thermally activated, time evolution of the film's coverage becomes a delicate function of both the temperature and pressure of the growth. The autocatalytic reaction (ACR) model, a rate equation known in chemical kinetics, is a powerful tool to describe such complicated temporal behaviors, and is successfully applied to analysis of dry oxidation at Si(001)-2 X 1 surfaces. Monte Carlo simulation indicates that the physics behind the ACR model lies in its effective inclusion of nucleation, growth, and coalescence processes.