Nanoindentation and nanoscratching studies of amorphous carbon films

Hydrogen-free amorphous carbon (a-C) films prepared by RF magnetron sputter ing were deposited on Si substrates in thin films, at various negative bias voltages V-b, (i.e. Ar-ion energies), and in thick layered-structure films with alternative values of V-b. The main purposes of this work are to pres ent preliminary results concerning the effect of Ar-ion bombardment during deposition on the elastic properties of thin a-C films with Ar+ energies in the range 30-200 eV, and the adhesion failure which limits their thickness and usefulness for practical applications, and the enhancement of hardness and scratch resistance of sputtered a-C films developed in a layered struc ture. The results show a significant improvement in the elastic properties of layered structure films and their stability. The combination of high har dness and relative low elastic modulus which the layered films exhibit make them more resistant to plastic deformation during contact, as confirmed by scratch testing. (C) 1999 Elsevier Science S.A. All rights reserved.