FLUORINE-ENHANCED OXIDATION OF SILICON - EFFECTS OF FLUORINE ON OXIDE STRESS AND GROWTH-KINETICS

The influence of fluorine on film stress as well as on oxide growth kinetics for oxide films grown by fluorine-enhanced thermal oxidation of silicon using NF3 as fluorine source is reported. The effect of NF3 concentration and oxidation temperature on the measured stress has been studied and compared to kinetics effects. A marked stress reduction while the oxidation rate is greatly enhanced can be observed in fluorinated oxides with respect to dry ones grown at the same temperature. This suggests a fluorine-related mechanism for stress relaxation. Moreover, a saturation of the stress relaxation with increasing fluorine exposure is observed which seems to be correlated with the saturation that we observed for the oxidation rate enhancement.