CHARACTERIZATION OF DIAMOND-LIKE CARBON THIN FILMS DEPOSITED BY FACING TARGETS SPUTTERING OF GLASS-LIKE CARBON

In this paper we have attempted to clarify the effect of the kinetic energy of the sputtered particles on the formation of diamond-like carbon thin films using a Facing Target Sputtering System(FTS) which allows deposition of films at a very low gas pressure such as 0.2mTorr. Glass-like carbon is a kind of amorphous carbon which has very small crystallites and its structure is very uniform compare to graphite. Therefore, we have also tried to evaluate the potential of glass-like carbon as sputtering targets. The optical properties of the carbon films were measured with an optical ellipsometer. The structure of the carbon films were evaluated from Raman spectroscopy. The electrical resistivity was measured using a four point probe technique. The mechanical properties were measured with a microscratch tester. The above experimental results indicate that the structure of FTS deposited carbon films changes from less amorphous to diamond-like as the argon gas pressure is decreased and their adhesion and uniformity was significantly improved. FTS carbon films about 300Å thick were also deposited on textured Co-Cr-Ta/Cr/Ni-P/Al 3.5"rigid disks for the characterization as wear resistant overcoats. The friction of the carbon films were measured using a computer-controlled constant linear velocity drag tester with a thin film head slider. The results show that the friction coefficient decreased from 0.95 to 0.45 as the argon gas pressure was decreased from 10mTorr to 0.2mTorr. Carbon films deposited at 0.2mTorr Ar pressure show significantly lower friction and much greater durability than those deposited at 10mTorr Ar pressure. These results support the conclusion that FTS deposited carbon films have excellent potential as high-durability overcoats.