This study focuses on modeling the chemical vapor deposition (CVD) of tantalum oxide, a high dielectric constant material, on silicon-based substrates. A three-dimensional model is developed and described for a CVD reactor in which tantalum ethoxide and oxygen precursors are used. The effect of pressure and substrate temperature on the deposition rate of thin films of tantalum oxide is studied at system pressures of 1-4 Torr and substrate temperatures in the range of 300-500 degrees C. Our model predictions and experimental data of a custom-made cold-wall CVD reactor are found to be in satisfactory agreement. The deposition rate is found to increase significantly with increasing substrate temperature; this suggests that the tantalum oxide CVD is surface-reaction-controlled.