材料期刊网

Raman spectra at visible and ultraviolet excitation of tetrahedral amorphous carbon (ta-C) films have been studied as a function of oblique angles of substrates while keeping the energy of incident particles stable. The substrate angle is varied from 0 to 60 degrees. The spectra show that the films contain less sp 3 content and more ordered sp 2 clustering as the substrate tilting angle increases from 0 to 60 degrees for thicker films of 70 rim, and also a decrease of sp 3 content for thinner films of 2 rim from 0 to 45 degrees. Raman data indicates the substrate tilting can dramatically lower internal stress while having less influence on hardness because hardness is related to sp(3) content, but internal stress is related to not only sp(3) content but the order of sp 2 cluster. And this is also consistent with the measurement of hardness and internal stress for thicker films of 70 nm. The implications of these results on the mechanisms proposed for the film formation were discussed. lt can provide a way for film application in magnetic recording slider that requires less internal stress and suitable hardness. (C) 2007 Elsevier B.V. All rights reserved.