The deposition and study of hard carbon films.

Carbon films have been deposited by rf plasma decomposition of methane at 50-1400V negative bias and 1.3x10 high minus 3 - 1.3x10 high minus 1 mbar pressure. Hardness, internal stress, density, hydrogen content, and infrared absorption depending on the preparation parameters have been measured. From the IR measurements the ratio of sp high 3 to sp high 2 bonds was calculated and the total amount of hydrogen in the films was determined by elastic recoil detection (0.5 bigger than H/C bigger than 0.15). We found in the range of bias voltages 0 smaller than the amount of (-V(B)) smaller than 100 V polymerlike films, in the range 100V smaller than the amount of (-V(B)) smaller than 600V diamondlike hard carbon films with high internal stress, and in the range 600 smaller than the amount of (-V(B)) smaller than 1400 V graphitelike soft films with low stress. The density of the diamondlike films was about 2g/cm high 3 and of the graphitelike films about 1.4g/cm high 3. The microhardness seem s to be correlated to the internal mechanical stress.