ELASTIC-MODULUS OF DIAMOND-LIKE CARBON-FILMS PREPARED BY PULSED VACUUM-ARC

Amorphous carbon films have been prepared by special pulsed vacuum are depositon methods allowing high currents up to 1 kA and more. The You ng's modulus of these films has been determined with respect to variou s technological parameters. For these measurements a method based on t he propagation of ultrasonic surface waves has been applied which has been specially designed for the investigation of thin films below one micrometer. Large changes of the elastic modulus, depending on the tec hnology, have been observed, contrasting with the common understanding of invariability of the elastic behaviour. Reflecting the large struc tural variations possible in amorphous carbon, the elastic modulus rep resents a suitable parameter for characterizing the carbon-carbon netw ork. Furthermore, the elastic modulus of amorphous carbon films may be used for a first estimation of film hardness because of the strong co rrelation of these two quantities.