Evolution of the granularity of discontinuous metal deposits during covering with a-C (or SiO)

The authors suggest a method which makes it possible to follow continuously, in situ, under UHV, the granulometric change of metallic condensates on carbon films before and during covering with a-C or SiO. For this purpose, they calculate separately the tunnel effect currents which flow between the grains from one interface to the next and directly between the particles. Fixing of the metal distribution does not occur as soon as evaporation of the a-C (or SiO) begins. When this fixing is achieved, a-C (or SiO) fills up the intergranular spaces until the grains are partially or entirely buried. During this burying, the thickness of the a-C layer in the intergranular spaces is compared with the height of the grains. They show that coalescence of the grains precedes the fixing of the deposit geometry. However, this coalescence is less pronounced that that observed between the end of deposit formation and the beginning of the covering. </jats:p