Patent ID: 7709398

Claim:
Process for depositing at least one layer, in particular semiconductor layer, on at least one substrate carried by a substrate holder in a process chamber of a reactor, the layer comprising at least two material components which are respectively introduced in the form of a first reaction gas and a second reaction gas into the reactor, where the reaction gases are decomposed as a result of a supply of energy and a part of the decomposition products form the layer, the supply of the first reaction gas, which has a low thermal activation energy, determining the growth rate of the layer, and the second reaction gas, which has a high thermal activation energy, being supplied in excess and in particular being preconditioned by independent supply of energy, the first reaction gas together with a carrier gas flowing in the direction generally normal to the substrate holder through a multiplicity of openings which are disposed distributed over a surface of a gas inlet member lying opposite the substrate holder forming together with said carrier gas a flow/diffusion boundary layer above the substrate, said boundary layer being dominated by flow of said carrier gas independently of flow of the second reaction gas, characterized in that the second reaction gas is preconditioned before it enters the process chamber and enters the process chamber at the edge of the substrate holder, immediately above the latter, and flows parallel to the substrate holder surface and is injected into said boundary layer simultaneously with the flow of the first reaction gas, and wherein a part of the decomposition products of both the simultaneously introduced first reaction gas and second reaction gas form the layer.