SiO2 chemical vapor deposition at room temperature using SiCl4 and H2O with an NH3 catalyst

Abstract

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+2H2O→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 angstroms/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. Show more