Silicon dioxide (SiO2) films were deposited at room temperature using a catalyzed chemical vapor deposition (CVD) reaction. The SiO2 film growth was accomplished using the reaction SiCl4 + 2H(2)O --> SiO2 + 4HCl and catalyzed with ammonia (NH3). The NH3 catalyst lowered the required temperature for SiO2 CVD from >900 K to 313-333 K. The ammonia also reduced the SiCl4 and H2O pressures required for efficient SiO2 CVD from several torr to <500 mTorr. In situ spectroscopic ellipsometry was used to optimize the reactant pressures, catalyst pressure, and reaction temperature. The ellipsometric investigations measured SiO2 CVD rates that varied from 0.1 Angstrom/min to >16 Angstrom/min depending on temperature and reactant pressures. Rutherford backscattering measurements obtained nearly stoichiometric SiO2 films with a Si/O ratio of 1:2.1. Atomic force microscopy images displayed a smooth SiO2 surface topography with a roughness similar to SiO2 CVD films grown at high temperatures. Catalysis by the NH3 Lewis base may be general and may facilitate the low temperature CVD of other materials.