N/sub 2/ gas absorption in cathodic arc apparatus with an Al cathode under medium vacuum

Al evaporation and N/sub 2/ absorption rates during cathodic arc evaporation with an Al cathode and N/sub 2/ gas flow were measured as a function of process pressure under medium pressure. These rates decreased as the pressure increased. The ratio of the Al evaporation rate to the N/sub 2/ absorption rate was about 2:1. The film deposited on the anode chamber was analyzed by an X-ray diffraction analyzer and found to be aluminum nitride (AlN). This result indicates that N/sub 2/ gas is mostly absorbed and fixed in the deposits on the anode surface in the form of AlN.