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

Al evaporation and N/sub 2/ absorption rates during a cathodic arc evaporation process with an Al cathode and N/sub 2/ gas flow are measured as a function of process pressure. These rates decrease as the pressure increases. The ratio of Al evaporation rate to N/sub 2/ absorption rate is about 2:1. The film deposited on the anode chamber is analyzed by XRD and found to be AlN. The result indicates that N/sub 2/ gas is mostly absorbed and fixed in the film as a form of AlN by the getter action of the Al ion.