抄録
R. F. reactive sputtering of iron in mixed argon-oxygen atmospheres has been investigated by means of measurements of deposition rate, electrical resistivity, and X-ray and electron diffraction. Thin films of iron oxides were deposited on glass, alumite, and (001) NaCl substrate, while changing the oxygen partial pressure from 2 × 10-4 to 5 × 10-2 Torr at a total pressure of 1.5 × 10 -2 Torr.
A hysteresis of the deposition rate was found in an increasing and decreasing cycle of the oxygen partial pressure. This phenomenon was explained by a model based on the relative relation between the sputtering rate and the oxidation rate of an iron target surface. Hence, two stationary reactive sputtering states were found to exist between certain critical values p* and p**, where the depositon rate changed drastically. One was a high deposition rate, the other was a low one, associated with a clean iron target and an'oxidized one, respectively. In the former state, Fe3O4 single phase films were obtained by controlling the deposition rate. Properties such as lattice constant, microstructure, and orientation of the deposited Fe3O4 films formed at various oxidation degrees were also examined.
