The Effects of Trace Amounts of Water on the Thermal Oxidation of Silicon in Oxygen

The significance of the addition of 25 ppm of to O 2 has been studied for the thermal oxidation of (100), (110), and (111) oriented silicon. With 25 ppm water addition to O 2 a sharp increase in the over‐all rate of oxidation was observed for each orientation and experimental temperature (800°, 927°, and 996°C). From data analysis in terms of a linear‐parabolic oxidation law, orientation effects were found for both the linear and parabolic rate constants and for both dry O 2 and added oxidations. The major effect of trace appears to be on the parabolic rate constants. The experimentally derived kinetic constants are interpreted in terms of surface geometry for the linear rate constants and in terms of the structure for the parabolic rate constants. The large kinetic effects observed with trace amounts of might be a cause for the disparity of literature results for dry thermal oxidation of silicon.