Kinetics of the silicon dioxide growth process in afterglows of microwave-induced plasmas

A fast flow reactor technique, by which thin silicon dioxide layers can be grown, is described in detail. Wafers 3 in. in diameter are treated in the afterglow of a microwave-induced plasma in oxygen/argon mixtures. This method allowed us to produce SiO2 layers of a uniform thickness up to 300 Å. It is shown that the oxide growth rate initially follows a parabolic dependence on the oxidation time while at thicknesses from about 170 Å on, a linear relationship is observed. Various physicochemical parameters affecting the oxidation rate are investigated, such as the flow velocity, the wafer position, the microwave power, and the temperature. It is also shown by chemical titration techniques that oxygen atoms in their electronic ground state are the major oxidizing species under the experimental conditions used.