Reactive sputtering of metals in oxidizing atmospheres

Abstract

A model is presented for the reactive sputtering of a metal in an oxygen-containing glow discharge. On this model spontaneous oxide formation on the target surface and a sharp decrease of the sputtering rate can occur at a definite oxygen partial pressure p* in the plasma. The pressure p* is essentially a function of the oxidation rate of the target relative to the sputtering rate. D.c. and r.f. sputtering experiments with iron and cobalt targets were found to be in good agreement with the given sputtering model. The experimental results of other authors can be understood in terms of the ideas of this work. The model, especially developed for the oxidation of a target, can be applied to other sputtering processes whenever a film is formed on the target surface consisting of a material different from the target material. © 1973.