Gas treatment systems

• US 20080173735A1
• Filed: 01/11/2008
• Published: 07/24/2008
• Est. Priority Date: 01/12/2007
• Status: Active Grant

• Current Assignee: Veeco Instruments Incorporated
• Original Assignee: Veeco Instruments Incorporated
• Inventors: Mitrovic, Bojan, Armour, Eric A., Gurary, Alex
• Granted Patent: US 8,152,923 B2
• Time in Patent Office: Days
• US Class Current: 239/548
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45574 Nozzles for more than one gas

Abstract

An MOCVD reactor such as a rotating disc reactor (10) is equipped with a gas injector head having diffusers (129) disposed between adjacent gas inlets. The diffusers taper in the downstream direction. The injector head desirably has inlets (117) for a first gas such as a metal alkyl disposed in radial rows which terminate radially inward from the reactor wall to minimize deposition of the reactants on the reactor wall. The injector head desirably also has inlets (125) for a second gas such as ammonia arranged in a field between the rows of first gas inlets, and additionally has a center inlet (135) for the second gas coaxial with the axis of rotation.

Claims

1. An injector head for a gas treatment reactor, the head comprising:

(a) a structure defining a plurality of gas inlets having openings facing in a downstream direction; and

(b) diffuser elements disposed between adjacent ones of the gas inlets, the diffuser elements extending in the downstream direction from the gas inlets and tapering in the downstream direction.

2. The injector head as claimed in claim 1 wherein said gas inlets are disposed in rows extending in one or more row direction transverse to the downstream direction and said diffuser elements include elongated blades extending in the row directions between adjacent rows of gas inlets.

3. The injector head as claimed in claim 2 wherein each of the elongated blades tapers to an edge.

4. The injector head as claimed in claim 1 wherein each of the diffuser elements tapers to a point.

5. The injector head as claimed in claim 4 wherein each of the diffuser elements is generally in the form of a pyramid.

6. The injector head as claimed in claim 1 wherein each diffuser element has side walls facing generally in opposite lateral directions transverse to the downstream direction and the side walls define an included angle of between 15 degrees and 75 degrees.

7. The injector head as claimed in claim 1 wherein the openings of the inlets are disposed in a plane transverse to the downstream direction and the diffuser elements project downstream from the plane.

8. A reactor comprising a reaction chamber, an injector head as claimed in claim 1 mounted to the reaction chamber, and a substrate carrier mounted in the chamber downstream from the injector head.

9. A reactor as claimed in claim 8 wherein the substrate carrier is rotatable around an axis substantially parallel to the downstream direction.

10. A reactor for gas treatment of one or more substrates with at least a first gas and a second gas, the reactor comprising:

a reactant chamber;

a substrate holder for supporting the one or more substrates mounted within the reactant chamber for rotation about an axis extending in upstream and downstream directions;

an injector head disposed upstream of the substrate holder, the injector head including structure defining;

a plurality of first gas inlets coupled to the first gas, the first gas reactant inlets being disposed in a first row extending in a first radial direction perpendicular to the axis and in a second row extending in a second radial direction perpendicular to the axis and perpendicular to the first radial direction; and

a plurality of second gas field inlets coupled to the second gas, the second gas field inlets being disposed in quadrants of the injector head around the axis between the rows of first gas inlets.

11. A reactor as claimed in claim 10 wherein the injector head further defines a center second gas inlet disposed at the axis.

12. A reactor as claimed in claim 11 further comprising one or more first gas control elements connected to the first gas inlets, one or more second gas field control elements connected to the second gas field inlets and a second gas center control element connected to the second gas center inlet, the second gas center control element being operable independently of the second gas field control elements.

13. A reactor as claimed in claim 10 wherein the injector head has a surface facing downstream and the second gas field inlets are disposed in an array extending over substantially the entire surface other than regions of the surface occupied by the first and second rows.

14. A reactor as claimed in claim 10 wherein the substrate holder is arranged to support one or more substrates so that surfaces of the substrates to be treated lie substantially perpendicular to the axis and face upstream.

15. A reactor as claimed in claim 10 wherein the first and second rows of first gas inlets extend to a first radial distance from the axis and wherein the second gas field inlets extend to a second radial distance greater than the first radial distance.

16. A method of treating one or more substrates comprising:

(a) rotating the substrates about an axis while maintaining surfaces of the substrates substantially perpendicular to the axis and facing in an upstream direction along the axis; and

, during the rotating step,

(b) discharging a first gas in the downstream direction toward the substrates from a first row of inlets extending across the axis in a first radial direction perpendicular to the axis and from a second row of inlets extending perpendicular to the axis in a second radial direction perpendicular to the first radial direction; and

simultaneously;

(c) discharging a second gas in the downstream direction toward the substrates from second gas field inlets disposed around the axis between the rows of first gas inlets.

17. A method as claimed in claim 16 further comprising discharging the second gas in the downstream direction toward the substrate from a center inlet disposed substantially on the axis.

18. A method as claimed in claim 17 further comprising controlling the discharge of the second gas from the center inlet independently of the flow of gas from the field inlets.

19. A method of treating one or more substrates comprising:

(a) rotating a disc-like holder carrying the substrates about an axis while maintaining surfaces of the substrates substantially perpendicular to the axis and facing in an upstream direction along the axis; and

, during the rotating step,

(b) discharging a first gas in a downstream direction parallel to the axis toward the substrates as a first set of gas streams extending to a first radial distance from the axis, and simultaneously discharging a second gas in the downstream direction as a second set of gas streams extending to a second radial distance from the axis greater than the first radial distance.

20. A method as claimed in claim 19 wherein the first set of gas streams is disposed in one or more rows extending in one or more radial directions from the axis and the second set of gas streams is disposed in regions around the axis.

21. A method as claimed in claim 20 wherein the first radial distance is less than the radius of the holder.

22. A method as claimed in claim 21 wherein the rotating and discharging steps are performed within a reactor vessel having internal wall surfaces in the form of surfaces of revolution coaxial with the axis.