THE MECHANICAL-PROPERTIES OF HYDROGENATED HARD CARBON-FILMS

Hydrogenated hard carbon films. deposited in a CH4 r,f. parallel plate discharge, have been evaluated by means of internal film stress and friction coefficient measurements. The internal stresses were estimated using a round silicon substrate made of both convex and concave Si wafers, combined with electrical capacitance measurements. The typical internal stress of the hard carbon film was compressive and was in the range 0.5-1.5 GPa. The variation in the film stress depending on the CH4 gas pressure during the film deposition was associated with the d.c. self-bias voltage on the cathode electrode. The friction coefficient between the hard carbon film deposited on a 3.5 in hard disk and a magnetic head was also examined.