The growth of silicon dioxide in a microwave discharge was investigated. The oxide growth can be characterized by a rate‐limiting diffusion process modified by sputtering effects produced by the discharge. Analysis of the growth behavior leads to the conclusion that a limiting oxide thickness is obtained at infinite time. The growth process provides a technique for rapidly oxidizing silicon at temperatures estimated to be 500°C or lower. At these low temperatures, growth rates corresponding to steam‐oxidization rates at 1100°C can be obtained. Films about 2000 Å thick can be grown in five minutes, and about 6000 Å thick in sixty minutes. High‐quality oxides are produced by this process with properties which are for the most part indistinguishable from those of thermally grown oxides. MOS capacitance—voltage measurements indicate that these oxides are essentially free of mobile ions.