Emission of dimers from the substrate during vacuum deposition of thin films

Emission of dimers from the substrate to the vapor medium during silver vapor deposition onto an ideal substrate is calculated. Dimers are demonstrated to form on the substrate owing to random collisions of atoms during their surface migration, and emission of dimers is caused by thermal fluctuations of the crystal lattice of the substrate. Calculations based on Langmuir’s modified model of sorption show that emission mainly occurs at the stage of filling of the first atomic layer on the substrate and in regimes of “condensation failure” when intense condensation does not occur even at high levels of supersaturation and nucleation frequency because of the low energy of bonding of vapor atoms with the substrate. A relation of emission of dimers to the intensity of condensation and condensate microroughness on the substrate is found.