Mo-Si-N films with a high nitrogen concentration were produced by sputter-deposition in nitrogen plasma. Chemical composition was determined with Rutherford backscattering and nuclear reaction analysis. Ratio of Mo to Si was 1:2 in the coatings with a nitrogen concentration of 50%. Microstructure of the as-deposited coatings on a silicon substrate was amorphous and no crystallization was found after annealing up to 1000(degree)C, although some relaxation was observed in X-ray diffraction. This was confirmed by high-resolution TEM. Hardness of Mo-Si-N films was 18.8 GPa as determined with a nanoindenter. This is significantly higher than that of MoSi(sub 2) films, 11.2 GPa. Hardness of the Mo-Si-N films increased to 24.4 GPa after annealing at 800(degree)C, which is the same as that of the tetragonal phase of MoSi(sub 2), 25.5 GPa. Similarly, modulus of as-deposited Mo-Si-N film was higher (257 GPa) than that of MoSi(sub 2) film (222 GPa). However, only a slight increase in the modulus of the Mo-Si-N film was found after annealing at 800C, whereas the modulus of the crystallized tetragonal MoSi(sub 2) was 382 GPa. No cracking was found in the Mo-Si-N films even after annealing at 1000C.
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