Gas inlet member of a CVD reactor

1. A gas inlet member ( 2 ) of a chemical vapor deposition (CVD) reactor, comprising a gas inlet housing which has at least one first gas distribution volume ( 5 ) that can be supplied with a first process gas by a first feed line ( 21 ) and has a multiplicity of first gas lines ( 8 ) which are each formed as a tube and have extensions ( 15 ) that engage in first openings ( 16 ) of a gas outlet plate ( 14 ) arranged in front of a gas inlet housing wall ( 10 ), and through which the first process gas enters a process chamber located beneath the gas outlet plate ( 14 ), and further comprising a clearance space ( 20 ) provided between the gas inlet housing wall ( 10 ) and the gas outlet plate ( 14 ), and a coolant chamber ( 7 ) that adjoins the gas inlet housing wall ( 10 ) and into which a coolant can be fed so as to cool the gas inlet housing wall ( 10 ), wherein the gas inlet housing has a second gas distribution volume ( 6 ) which can be fed by a second feed line ( 23 ) and which is connected to the gas inlet housing wall ( 10 ) via a multiplicity of second gas lines ( 9 ), wherein the second gas lines ( 9 ) open into the clearance space ( 20 ), characterized in that outlet ( 8 ′) ends of extensions ( 15 ) of the gas lines ( 8 ) are in heat-conductive contact with the cooled gas inlet housing wall ( 10 ), and the gas outlet plate ( 14 ) is thermally decoupled with respect to the gas inlet housing wall ( 10 ) in such a manner that the gas outlet plate ( 14 ), which is acted on by radiation heat from a process chamber ( 22 ), heats up more intensely than the outlet ( 8 ′) ends which extend into the first openings ( 16 ) of the gas outlet plate ( 14 ).

2. The gas inlet member ( 2 ) according to claim 1 , further characterized in that the outlet ( 8 ′) ends of the first gas lines ( 8 ) are substantially flush with a surface of the gas outlet plate ( 14 ) facing the process chamber ( 22 ), or can be brought into a position flush with said surface by vertically displacing the gas outlet plate ( 14 ).

3. The gas inlet member ( 2 ) according to claim 1 , further characterized in that the gas outlet plate ( 14 ) has second openings ( 18 ) through which a second process gas can enter the process chamber ( 22 ).

4. The gas inlet member ( 2 ) according to claim 3 , further characterized in that gas line extensions ( 15 ), with which the first gas lines ( 8 ) protrude into the first openings ( 16 ) associated with the first gas lines, have an outer diameter that is smaller than an opening width of the first openings ( 16 ), so that each of the gas line extensions ( 15 ) is surrounded by an annular gap ( 17 ).

5. The gas inlet member ( 2 ) according to claim 4 , further characterized in that the outlet ( 8 ′) ends of the first gas lines ( 8 ) in the gas outlet plate ( 14 ) are positioned on vertices of equilateral triangles.

6. The gas inlet member ( 2 ) according to claim 5 , further characterized in that the second openings ( 18 ) are positioned on centers of the equilateral triangles.

7. The gas inlet member ( 2 ) according to claim 1 , further characterized in that each of the first gas lines ( 8 ) is surrounded by a purge gas or process gas line ( 26 ), that is fed by a third gas distribution volume ( 25 ).

8. The gas inlet member ( 2 ) according to claim 1 , further characterized in that the gas outlet plate ( 14 ) is temperature-controlled and includes temperature-regulating channels ( 19 ).

9. The gas inlet member ( 2 ) according to claim 1 , further characterized in that a distance (H) between the gas inlet housing wall ( 10 ) and the gas outlet plate ( 14 ) and a distance of the gas outlet plate ( 14 ) from a susceptor ( 3 ) can be varied by means of a displacement device ( 31 ).

10. The gas inlet member ( 2 ) according to claim 1 , further characterized in that, for each of the first openings ( 16 ), the first opening ( 16 ) is an interior of a sleeve ( 30 ) that extends into the clearance space ( 20 ).

11. The gas inlet member ( 2 ) according to claim 1 , further characterized in that the thermal conductivity of the gas outlet plate ( 14 ) is less than the thermal conductivity of the first gas lines ( 8 ).

12. A gas inlet member ( 2 ) of a chemical vapor deposition (CVD) reactor, comprising a gas inlet housing which has at least one first gas distribution volume ( 5 ) that can be supplied with a first process gas by a first feed line ( 21 ) and has a multiplicity of first gas lines ( 8 ) which are each formed as a tube and have extensions ( 15 ) that engage in first openings ( 16 ) of a gas outlet plate ( 14 ) arranged in front of a gas inlet housing wall ( 10 ), and through which the first process gas enters a process chamber located beneath the gas outlet plate ( 14 ), and further comprising a clearance space ( 20 ) provided between the gas inlet housing wall ( 10 ) and the gas outlet plate ( 14 ), wherein the extensions ( 15 ) have an outer diameter that is smaller than an opening width of the first openings ( 16 ), so that each of the extensions ( 15 ) is surrounded by an annular gap ( 17 ), characterized in that the gas outlet plate ( 14 ) is displaceable in a direction parallel to its plane of extent in such a manner that the gas outlet plate ( 14 ) can be brought into heat-conductive contact with the extensions ( 15 ).

13. The gas inlet member ( 2 ) according to claim 12 , further characterized by a profile ( 28 , 29 ) of the first openings ( 16 ) which influences gas flow through the first openings ( 16 ).