KINETICS AND OXIDE PROPERTIES OF SILICON OXIDATION IN O2-H2-HCL MIXTURES

The thermal oxidation kinetics of silicon in O2-H2-HCl mixtures and the electrical properties of the silicon dioxide films grown in the mixtures have been studied in order to characterize the effect of H2O and C12 on silicon oxidation. Oxidations were carried out at 1100°C over a wide range of H2 and HC1 flow rates at a constant O2 flow rate. The partial pressures of O2, H2, H2O, HC1, and C12 were calculated trom equilibrium chemical thermodynamics. Parabolic rate constants were calculated from the o2 and H2O partial pressures and the values were in quite good agreement with the experimental data. But the experimental data showed that linear rate constants were greatly dependent on C12 partial pressure. The effective mobile ion density depended only on the C12 partial pressure (pc12) and was independent of the H2O partial pressure. The effective mobile ion density was rapidly decreased with increasing pc12 before it approached a minimum constant value. The fixed charge density also depended only on pc12, but the decreasing rate with increasing pc12 was small. © 1979, The Electrochemical Society, Inc. All rights reserved.