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Eigenspannungen und E-Modul von DLC-Schichten und ihr Bezug zur Struktur und dem Abscheideprozeß

Internal stresses and elastic modulus of DLC films and their relation to structure and deposition process
 

Hecht, G. ; Societe Francaise du Vide -SFV-, Paris; Deutsche Vakuum-Gesellschaft:
Thin Films. Proceedings of the joint 4th International Symposium on Trends and New Applications in Thin Films TATF '94 and the 11th Conference on High Vacuum, Interfaces and Thin Films HVITF '94
Oberursel: DGM-Informationsgesellschaft, 1994
ISBN: 3-88355-199-6
pp.429-432
International Symposium on Trends and New Applications in Thin Films (TATF) <4, 1994, Dresden>
Conference on High Vacuum, Interfaces and Thin Films (HVITF) <11, 1994, Dresden>
German
Conference Paper
Fraunhofer IWS ()
a-C film; a-C Schicht; diamantähnliche Kohlenstoffschicht; diamond-like carbon film; DLC; E-Modul; innere Spannung; internal stress; mechanical property; mechanische Eigenschaft; Ultraschalloberflächenwelle; ultrasonic surface wave; Young's modulus

Abstract
The elastic moduli directly reflect binding strength and structure. Usually these factors can be only sligthly modified within a given material, and the elastic moduli are not very sensitive to any modifications. However, large variations of Young's modulus from less than 100 GPa up to more than 500 GPa are found in amorphous carbon films. This can be attributed mainly to the varying fraction of sp (exp 3) and sp (exp 2) bonds. Furthermore, the structural order should be of essential influence: for hard amorphous carbon films even nearly complete sp (exp 3) binding type the modulus achieves only 30-50 % of that of crystalline diamond. The Young's modulus has been measured for a broad variety of preparation conditions. The method is based on the determination of the frequency dependent propagation velocity of ultrasonic surface waves and its mathematical evaluation. Within simplified models the results are related to the distribution of binding types on the atomic scale and on the mesos copic level as well. It is shown that the elastic modulus can suitable be used for an effective characterization of DLC films. The relevance of structural differences, revealed in this way, is discussed with respect to other mechanical properties.

: http://publica.fraunhofer.de/documents/PX-10796.html