The invention relates to a method and device for depositing at least one layer, particularly a semiconductor layer, onto at least one substrate, which is situated inside a process chamber of a reactor while being supported by a substrate holder. The layer is comprised of at least two material components provided in a fixed stoichiometric ratio, which are each introduced into the reactor in the form of a first and a second reaction gas, and a portion of the decomposition products form the layer, whereby the supply of the first reaction gas, which has a low thermal activation energy, determines the growth rate of the layer, and the second reaction gas, which has a high thermal activation energy, is supplied in excess and is preconditioned, in particular, by an independent supply of energy. The first reaction gas flows in a direction toward the substrate holder through a multitude of openings, which are distributed over a surface of a gas inlet element, said surface being located opposite the substrate holder. According to the invention, the second process gas is preconditioned with a plasma before entering the process chamber, and it enters the process chamber at the edge of the substrate holder directly thereabove and flows parallel to the substrate holder surface.