Sticking of particles (molecules) of a substance to the surface of a solid. Mechanisms to stick the particles are Physisorption and Chemisorption, where Chemisorption causes much higher contact forces.
Adsorption to a surface is only possible, if the substances can get immediate contact. Usually this requirement can only be achieved if separating layers are removed from the substrate before. Plasmacleaning may be the best method to remove any particle of a separating layer. Adsorption may be increased by Plasma activation and Plasma etching and may be decreased if desired by Plasmacoating with appropriate layers.
Adsorption must be differentiated from Absorption which designates the incorporation of particles of a substance into the bulk of another substance.