ION-BEAM-ASSISTED DEPOSITION OF MOLYBDENUM NITRIDE FILMS

A series of molybdenum nitride films was synthesized by electron beam evaporative deposition of molybdenum, with simultaneous bombardment by nitrogen ions from a Kaufman ion source. The nitrogen ions were accelerated to 500 or 1000 eV. The film compositions and structures were determined using Rutherford backscattering spectrometry and X-ray diffraction respectively. Effective reflection and sputtering coefficients for nitrogen incident on the molybdenum nitride surfaces were extracted from the data. These coefficients were used to calibrate the deposition system and allowed the deposition of molybdenum nitride films with control of the nitrogen atom concentration to +/-2.3 at.%. In general, the films were polycrystalline with a high degree of texturing. The phases found in order of increasing measured nitrogen content were as follows: gamma-Mo2N (f.c.c.), beta-Mo16N7 (b.c.t.), B1-MoN (f.c.c.) then delta-MoN (h.c.p.).