A mathematical model has been developed to study the chemical vapor deposition of SiO2 from TEOS and ozone in a cold-wall separate-gas-injection reactor related to the commercial Watkins-Johnson 7000. The model employs the kinetic scheme proposed previously by Kim and Gill. Control-volume-based finite difference methods are used to solve for the two-dimensional fluid velocity, temperature, and concentration distributions. The model successfully describes experimental data of film thickness profiles available. We systematically investigate the dependence of deposition rate on operating conditions including O3/TEOS ratio, reactant flow rate, and injector-wafer spacing. The predicted results indicate that a high TEOS flow rate and an O3/TEOS ratio of around 30 are preferable for obtaining high deposition rates and good film quality.