Modeling of silicon dioxide chemical vapor deposition from tetraethoxysilane and ozone

Chemical Vapor Deposition (CVD) of silicon dioxide from tetraethoxysilane (TEOS) and ozone was modeled using CHEMKIN-III simulation software. Modeling assumed that film growth proceeds via the fast oxidation of silicon-bearing compounds by ozone or atomic oxygen at the substrate surface. The objective of the study was to use kinetic data from the literature to develop a reliable reaction model with no more than one adjustable parameter. The simulations established that direct contribution of TEOS surface reactions to film growth is negligible in TEOS/ozone CVD. Depositions at low TEOS flow rates are controlled by diffusion of intermediate silicon-containing compounds formed in the gas phase by reaction of TEOS with atomic oxygen. The depletion of ozone or atomic oxygen within the reactive boundary layer becomes rate limiting at high TEOS hows, while gas-phase polymerization reactions reduce the rate at high pressures. Close agreement with the published rate data was obtained for reactions at 643 K but discrepancies remain at higher deposition temperatures. II is believed that the model overpredicts the formation rate of intermediates at high temperatures because the mechanism fails to fully account for gas-phase oxidation reactions between atomic oxygen and the organic fragments from TEOS oxidation reactions. (C) 2001 The Electrochemical Society. All rights reserved.