Properties and durability of thin a-C : H overcoats produced by plasma enhanced chemical vapor deposition

Radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) techni que was used to deposit thin amorphous hydrogenated carbon (a-C:H) overcoat s on glass ceramic disc substrates. Raman spectroscopy results showed that higher sp(3) carbon content films can be obtained by applying appropriate k inetic energy of ion bombardment (similar to 100 eV) during film growth. Ho wever, a higher content of hydrogen was also observed in such films. The re sults suggest that a certain fraction of sp(3) carbon bonds is likely to be terminated by hydrogen and become dangling bonds. These dangling bonds may be important to the durability performance in the tribe-contact interface. The highly hydrogenated carbon overcoats (similar to 40 at.%) showed signi ficant improvement in tribological performance compared with the less hydro genated films. The contact-start-stop test at ambient environment of such o vercoats showed good durability over 10 K cycles at the him thickness of 3. 6 nm. (C) 2000 Elsevier Science B.V. All rights reserved.