Preparation of CoxN Thin Films by the Ion Reacting Deposition Method

The formation of cobalt-nitride thin films by the ion reacting deposition method was investigated. A low-energy broad-beam ion source (Kaufman type) was used for ionizing nitrogen. X-ray diffraction spectra revealed that the N-rich cobalt nitrides Co3N and Co2N were formed only at low ion current densities during deposition. The magnetic properties of the films changed suddenly with increasing Jion. Hc was maximum at Jion=1.5 (mA/m²)/(A/s), above which the N-poor compound Co4N was formed. The nitrogen which was contained in films but was not involved in the nitriding reaction, was degassed above 250°.