PHOSPHORUS INCORPORATION EFFECTS IN SILICON DIOXIDE GROWN AT LOW-PRESSURE AND TEMPERATURE

Phosphine incorporation is avoided through proper selection of the oxygen/silane mole ratio. Typical reflow processing results in removal of phosphine from oxides grown under other than optimum conditions. Although the majority of the phosphorus appears in the form of phosphorus pentoxide in all cases, the trioxide also is present, except when the total phosphorus content is less than approximately 2 weight percent. The efficiency of phosphorus incorporation is reduced for increased growth temperature, flow rate, or pressure. This temperature effect, as well as a reduction in activation energy for doped-oxide growth, is in large part interpretable in terms of a temperature-insensitive phosphine/oxygen reaction. The oxide growth rate is increased and the stress level is reduced through phosphorus incorporation.