The most common method of epitaxy. The material to be deposited on the substrate is heated to gaseous form in a deposition furnace that also contains the substrate material. The substrate is held at a temperature just below the solidification point. As the gas molecules reach the substrate they are deposited on the surface, replicating the substrate crystal structure. The conditions in the deposition furnace can be adjusted with respect to temperature and pressure to allow particular desired combinations of substrate and deposited material to be produced. See also chemical vapour deposition.