Intrinsic stress measured on ultra-thin amorphous carbon films deposited on AFM cantilevers

Ultra-thin amorphous carbon films were deposited onto atomic force cantilev ers by plasma enhanced chemical vapour deposition. High magnification scann ing electron micrographs at 30 kV reveal that the AFM tip is not affected b y the deposition but its radius is broadened by the presence of the coating . Energy dispersive X-ray analysis at 4 kV shows that the film mostly coats one side of the lever, resulting in a bending of the cantilever, readily o bservable by scanning electron microscopy. This deformation is elastic and is caused by an internal compressive stress of 2.60 and 2.54 GPa, respectiv ely, for 20-nm and 110-nm-thick films. After 15 at.% Si incorporation, thes e stresses are reduced to 0.97 and 0.78 GPa. It is believed that the increa sed hydrogenation upon silicon addition causes a loosening of the carbon ne twork structure and is, therefore, responsible for the observed stress reli ef. (C) 2001 Elsevier Science B.V. All rights reserved.