Influence of technological conditions on mechanical stresses inside diamond-like carbon films

In this paper the influences of the technological conditions, i.e. the influences of the hydrogen flow rate and deposition time, on the values of the intrinsic mechanical stresses inside the diamond-like carbon (DLC) thin films prepared by plasma enhanced chemical vapor deposition onto silicon substrates are studied. These stresses are measured by two-beam interferometry and optical profilometry based on chromatic aberration through the measurements of deformations of the silicon substrates originating in consequence of the film stresses. It is shown that the influence of the deposition time (i.e. film thickness) on the film stress is relatively slight in contrast to the influence of the hydrogen flow rate on this quantity. It is namely shown that the film stresses are influenced by the hydrogen flow rate values in a pronounced way within the interval of interest, i.e. within the interval 1-7 sccm. Moreover, it is shown that the method of optical profilometry used can be competitive to the method of two-beam interferometry from the practical point of view. (c) 2005 Elsevier B.V. All rights reserved.