HARD BORON SUBOXIDE-BASED FILMS DEPOSITED IN A SPUTTER-SOURCED, HIGH-DENSITY PLASMA DEPOSITION SYSTEM

Boron-suboxide-based thin films have been deposited on Si in an electr on cyclotron resonance microwave plasma using a radio frequency (rf) m agnet-on as a source of boron. Variations of the oxygen fraction in th e deposition ambient and of the rf bias applied to the substrate were related to film tribology. The best films have hardnesses of similar t o 28 GPa and moduli of similar to 240 GPa and were deposited in oxygen fractions < 1% at substrate temperatures < 350 degrees C. The films c ontain 4% - 15% O and similar to 15% C with carbon originating from th e sputter target. They are amorphous and have surface roughnesses of s imilar to 0.2 nm. Boron-oxide films may form a self-generating lubrica ting layer of B(OH)(3) in ambient atmosphere. Compositional depth prof iling of these films reveals an oxygen-enriched surface of similar to 10 nm thickness. Initial nanoscratch test results indicate that these films fail at high critical loads and have low friction coefficients r elative to other hard coatings. (C) 1997 American Vacuum Society.