ChemInform Abstract: REEXAMINATION OF SOME ASPECTS OF THERMAL OXIDATION OF SILICON

This paper reports a study of the water vapor pressure and low level sodium impurity dependence of the oxidation rate of silicon at 1000° and 1230° C. The oxidation studies were carried out in an rf heated cold wall oxidizer which is also described. The important aspect of the oxidizer is that the sample is placed between two closely spaced silicon blocks to give a very uniform temperature region and therefore uniform oxide properties. It is shown that the oxidation rate coefficient (in the parabolic range) increases monotonically with water vapor pressure. However, the rate also shows some dependence on the other gas phase constituents. At constant partial pressure the parabolic rate constant increases, going from mixture to pure (vacuum) or mixture. For sodium concentrations in the range 0.4–10 ppm (atomic) in the water vapor atmosphere no changes in oxidation rate were observed at 1000° or at 1230° C.