Patent ID: 6972050

Claim:
Method for depositing in particular crystalline layers on in particular crystalline substrates in a process chamber of a CVD reactor, in which at least a first reaction gas and a second reaction gas are passed through separate feedlines into in each case a gas outlet zone in an entry zone of the process chamber, in which method the gas outlet zones lie one above the other between the process chamber base and the process chamber cover and have different heights, in which method the first reaction gas, if appropriate together with a carrier gas, flows out of the gas outlet zone adjacent to the process chamber base, and in which method a carrier gas is ad-mixed at least with the second reaction gas which flows out of the gas outlet zone which is remote from the process chamber base and the flow parameters are selected in such a way that the second reaction gas decomposes pyrolytically substantially only in the entry zone, and the decomposition products diffuse, in a deposition zone disposed downstream of the entry zone, transversely with respect to the direction of flow of the gases, to a substrate disposed on the process chamber base where, together with decomposition products of the first reaction gas, they condense to form a layer, characterized in that the kinematic viscosity of the carrier gas which is admixed with the second reaction gas is set, in particular by mixing two gases of very different kinematic viscosity, in such a manner that the quotient of the Reynolds numbers in the two gas outlet zones, given substantially approximately equal mean gas velocities, is approximately one.