A technique used during the manufacture of electronic circuits and components in order to produce a coating or thin film of one solid material on the clean surface of another, in particular a metal on a semiconductor. The solid to be deposited is heated in a vacuum in the presence of the cool substrate material. Atoms evaporated from the material (either in solid or liquid form) suffer few collisions from the residual low-pressure gas and travel directly to the substrate. They condense on the substrate surface and form a thin film. See also thin-film circuit.