an upper crucible part comprises several chambers containing a supersaturated growth solution with which a semiconductor wafer is coated with a monocrystalline semiconductor layer by way of epitaxial growth . the semiconductor wafer is contained in a cassette - shaped lower part which is moved underneath the upper part . the coating itself is effected within a protective - gas atmosphere within a reaction space which , by a diffusion furnace , is heated up to a temperature which is very exactly adhered to . in order to avoid a frequent cooling of the reaction space due to exposure to the ambient temperature and subsequent re - heating , the system comprises a loading station into which several lower crucible parts together with the semiconductor wafers , with the exclusion of air , are introduced into the reaction space and an epitaxial - growth region through which the lower crucible parts are moved successively below the stationarily arranged crucible part , as well as an unloading station in which the lower crucible parts , with the exclusion of air , are removed from the reaction space .