Silicon Oxidation Studies: Some Aspects of the Initial Oxidation Regime

Abstract

This study is concerned with the initial regime (i.e. up to 200A SiO2 thickness) of the thermal oxidation of single crystal Si. The kinetic data (SiO2 film thickness vs. time of oxidation) has been generated at 780°, 893°, and 980°C in dry O2 and H2O-N2 ambients and measured using an automated ellipsometer which follows the oxidation in situ. The data for the dry O2 oxidation is considerably more linear than for the data produced from H2O containing ambients which exhibit parabolic behavior. This may be attributed to a greater protectiveness for oxides grown in H2O. Dielectric breakdown measurements show that there are fewer defects in the H2O grown thin SiO2 films. Transmission electron microscopy observations show that the films contain inhomogeneities which are smaller than 50A. Therefore, the conclusion is that the pore structure is different in dry and wet grown SiO2 films and that this microstructure is responsible for both the oxidation data and dielectric breakdown differences. © 1978, The Electrochemical Society, Inc. All rights reserved.