초록 ▼

The invention relates to a method for depositing especially, crystalline layers onto especially, crystalline substrates, in a process chamber of a CVD reactor. At least one first and one second reaction gas are each led into a gas outlet area in an input area of the process chamber, by means of sepa

The invention relates to a method for depositing especially, crystalline layers onto especially, crystalline substrates, in a process chamber of a CVD reactor. At least one first and one second reaction gas are each led into a gas outlet area in an input area of the process chamber, by means of separate delivery lines. The gas outlet areas lie one above the other between the floor of the process chamber and the cover of the process chamber and have different heights. The first reaction gas flows out of the gas outlet area that is situated next to the process chamber floor, optionally together with a carrier gas. A carrier gas is added at least to the second reaction gas, which flows out of the gas outlet area lying further away from the process chamber floor. The flow parameters are selected in such a way that the second reaction gas is essentially only pyrolytically decomposed in the inlet area and the products of decomposition diffuse crosswise to the direction of Dow of the gases to a substrate located on the process chamber floor, in a deposition area which is located downstream of the input area. Upon reaching said substrate, said products of decomposition condense to form a layer, together with products of decomposition of the first reaction layer. The invention aims to ensure that the decomposition of the organometallic products of decomposition takes place essentially only in the inlet area, even in the case of longer deposition areas, and to ensure that the partial pressures of the products of decomposition (depletion) in the gas phase above the deposition area maintain an essentially linear course. To this end, the invention provides that the kinematic viscosity of the carrier gas that is added to the second reaction gas is adjusted, especially by mixing two gases which differconsiderably in terms of their kinematic viscosity, in such a way that the quotient of Reynolds numbers in the two gas outlet areas is approximately one for essentially approximately identical average gas speeds.

대표청구항 ▼

1. 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

1. 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.2. Method according to claim 1, or in particular according thereto, characterized in that the carrier gases and used are hydrogen and/or nitrogen.3. Method according to claim 1 or in particular according thereto, characterized in that the first reaction gas is a metal hydride, for example phosphine and/or arsine.4. Method according to claim 1 or in particular according thereto, characterized in that the second reaction gas is a metalorganic compound, for example trimethylgallium and/or trimethylindium.5. Device for carrying out a method according claim 1, having a process chamber into which at least a first reaction gas and a second reaction gas, together with a carrier gas, are passed through separate feed lines into in each case a gas outlet zone in an entry zone of the process chamber, the gas outlet zones lying one above the other between the process chamber base and the process chamber cover and having different heights, the gas outlet zones which lie one above the other being adjoined in the downstream direction by an entry zone for pyrolytic decomposition of the reaction gas which flows out of the gas outlet zone which is remote from the process chamber base, and a deposition zone, which is disposed downstream of the entry zone and in which there are one or more substrate holders, the sum of the lengths of the entry zone and deposition zone being at least 35 cm, the sum of the heights and of the two gas outlet zones being at least 4 cm, the length of the deposition zone being at least 20 cm, and the ratio of the heights of the gas outlet zone which is remote from the process chamber base and of the gas outlet zone which is adjacent to the process chamber base being greater than four, and at least two carrier gas feed lines for different carrier gases, each having a gas flow controller, opening out into the feed line for the second reaction gas.6. Device according to claim 5 or in particular according thereto, characterized in that the height of the second gas outlet zone associated with the second reaction gas is at least twice as great, in particular at least four times as great, preferably five times as great, as the height of the first gas outlet zone associated with the first reaction gas.7. Device according to claim 5 or in particular according thereto, characterized in that the process chamber is in the shape of a cylinder with a gas feedline located in the center and a heated process chamber base on which there are disposed substrate holders which are driven in rotation in the manner of satellites.8. Method for depositing in particular crystalline layers on in particular crystalline substrates in a process chamber of a CVD reactor, in which method 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, which are separated from one another by means of a gas outlet flange, are located one above the other between the process chamber base and the process chamber cover, in which method the first reaction gas, if appropriate 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 admixed 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 re-action gas decomposes pyrolytically substantially only in the entry zone, and the de-composition 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 heights of the gas outlet zones, in particular through the selection of a suitable gas outlet flange, are set in such a manner that the quotient of the Reynolds numbers in the two gas out-let zones, given substantially equal mean gas velocities, is approximately one.9. Device for carrying out a method according to claim 8, having a process chamber into which at least a first reaction gas and a second reaction gas, together with a carrier gas, are passed through separate feedlines into in each case a gas outlet zone in an entry zone of the process chamber, the gas outlet zones, which are separated from one another by means of a gas outlet flange, being located one above the other between the process chamber base and the process chamber cover, the gas outlet zones which are located one above the other being adjoined in the downstream direction by an entry zone for pyrolytic decomposition of the reaction gas flowing out of the gas outlet zone which is remote from the process chamber base, and a deposition zone, which is disposed downstream of the entry zone and in which there are one or more substrate holders, characterized in that the heights of the gas outlet zones can be set in particular by selection of a suitable gas discharge flange.10. Device according to claim 8 or in particular according thereto, characterized in that the spacing between a flange collar, which is in the form of an annular disc, of the gas outlet flange and the upper boundary of the gas outlet zone which is remote from the process chamber base can be adjusted by axial displacement of a thick-walled tube.11. The device according to claim 9 wherein the discharge flange is adjustable in height.