Method of forming an iron oxide film by reacting sputtering with control of a glow discharge by monitoring an emission spectrum of iron from the glow discharge

摘要

In a method of forming an iron oxide film of either Fe.sub.3 O. sub.4 or &agr;-Fe.sub.2 O.sub.3 on a substrate with reactive sputtering of a target of iron, intensity of an emission spectrum of iron is previously determined as a predetermined value in connection with a desired one of Fe.sub.3 O.sub.4 and &agr;-Fe.sub.2 O.sub.3 films. A light beam emitted from the glow discharge is measured to produce an electric signal representative of intensity of a measured spectrum of iron. Control operation is carried out to adjust the measured spectrum to the predetermined value. The electric signal may control either a flow rate of introducing oxygen gas into the space or intensity of an electric field produced between the substrate and the target.