Chemical vapor deposition apparatus

• US 6,197,121 B1
• Filed: 06/30/1999
• Issued: 03/06/2001
• Est. Priority Date: 11/27/1996
• Status: Expired due to Term

• Current Assignee: Veeco Instruments Incorporated
• Original Assignee: Emcore Corporation
• Inventors: Stall, Richard A., Salagaj, Thomas, Zawadzki, Peter, Karlicek, Robert F. Jr., Gurary, Alexander I.
• Primary Examiner(s): BUEKER, RICHARD R
• Application Number:
  US09/345,032
• Time in Patent Office: 615 Days
• Field of Search: 118/715, 118/719, 118/724, 118/725, 118/730
• US Class Current: 118/725
• CPC Class Codes: C23C 16/45514 Mixing in close vicinity to the substrate
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: C23C 16/45572 Cooled nozzles
• CPC Class Codes: C23C 16/45574 Nozzles for more than one gas
• CPC Class Codes: C23C 16/45591 Fixed means, e.g. wings, baffles
• CPC Class Codes: C23C 16/4584 the substrate being rotated
• CPC Class Codes: C30B 25/14 Feed and outlet means for the gases; Modifying the flow of the reactive gases

Abstract

Reactors for growing epitaxial layers on substrates are disclosed including rotatable substrate carriers and injectors for injecting gases into the reactor towards the substrates on the carriers and including a gas separator for separately maintaining various gases between gas inlets and the injector. Various reactor embodiments are disclosed including removable gas separators, and particular injectors which include cooling channels, as well as flow restrictors mounted within the reactors to restrict the flow of the gases to the substrates from the injector, and heaters mounted within the rotatable shell holding the substrate carriers so that the heaters can be accessed and removed through a lid forming a wall of the reactor.

Claims

1. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a first gas inlet, a second gas inlet, an injector for injecting said first and second gases into said reactor chamber in a first direction towards said substrate carrier, and a gas separator disposed between said first and second gas inlets and said injector for separately maintaining said first and second gases in a single plane parallel to said substrate carrier for separately distributing said first and second gases within said single plane transverse to said first direction and over the surface of said injector, said first and second gas inlets supplying said first and second gases directly to said gas separator substantially in said first direction whereby said first and second gases are separately maintained until said first and second gases approach said substrate carrier.

2. The reactor of claim 1 wherein said gas separator includes first and second gas chambers in said plane parallel to said substrate carrier.

3. The reactor of claim 2 including a carrier gas inlet, and wherein said gas separator includes a third gas chamber between said first and second gas chambers for separately maintaining said carrier gas between said gas inlets and said injector, said injector thereby injecting said carrier gas into said chamber towards said substrate carrier between said first and second gases in order to maintain said first and second gases separate from each other.

4. The reactor of claim 1 wherein said gas separator includes first and second gas receiving portions for receiving said first and second gases from said first and second gas inlets, first and second gas chambers for distributing a quantity of said first and second gases prior to entry of said first and second gases into said injector, and wall means separating said first and second gas receiving portions from said first and second gas chambers, said wall means including an aperture for permitting said first and second gases to pass from said first and second gas receiving portions to said first and second gas chambers.

5. The reactor of claim 4 wherein said first and second gas chambers have a configuration defined by an arc of a circle.

6. The reactor of claim 1 including a mesh screen disposed between said gas separator and said injector for further distributing said first and second gases.

7. The reactor of claim 1 wherein said injector includes a plurality of gas passages for said first and second gases.

8. The reactor of claim 7 wherein said injector includes a cooling passage for cooling said first and second gases passing through said plurality of gas passages.

9. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber towards said substrate carrier in a first direction, and a removable gas separator removably disposed between said gas inlet and said injector for maintaining said gas in a predetermined portion of said gas separator, whereby said gas separator can be replaced with a different gas separator, said gas separator including a gas receiving portion for receiving said gas from said gas inlet substantially in said first direction, a gas chamber for distributing a quantity of said gas in a direction substantially transverse to said first direction prior to entry of said gas into said injector, and wall means separating said gas receiving portion from said gas chamber, said wall means including an aperture for permitting said gas to pass from said gas receiving portion to said gas chamber.

10. The reactor of claim 9 wherein said gas separator includes a gas receiving portion for receiving said gas from said gas inlet, a gas chamber for distributing a quantity of said gas prior to entry of said gas into said injector, and wall means separating said gas receiving portion from said gas chamber, said wall means including an aperture for permitting said gas to pass from said gas receiving portion to said gas chamber.

11. The reactor of claim 9 including a mesh screen disposed between said gas separator and said injector for further distributing said gas.

12. The reactor of claim 9 wherein said gas inlet comprises a first gas inlet, and including a second gas inlet, whereby said injector injects said first and second gases into said reactor towards said substrate carrier, and said removable gas separator maintains said first and second gases separate from each other.

13. The reactor of claim 12 wherein said gas separator includes first and second gas chambers.

14. The reactor of claim 13 including a carrier gas inlet, and wherein said gas separator includes a third gas chamber between said first and second gas chambers for separately maintaining said carrier gas between said gas inlets and said injector, said injector thereby injecting said carrier gas into said chamber towards said substrate carrier between said first and second gases in order to maintain said first and second gases separate from each other.

15. The reactor of claim 12 wherein said gas separator includes first and second gas receiving portions for receiving said first and second gases from said first and second inlets, first and second gas chambers for distributing a quantity of said first and second gases prior to entry of said first and second gases into said injector, and wall means separating said first and second gas receiving portions from said first and second gas chambers, said wall means including an aperture for permitting said first and second gases to pass from said first and second gas receiving portions to said first and second gas chambers.

16. The reactor of claim 15 wherein said first and second gas chambers have a configuration defined by an arc of a circle.

17. The reactor of claim 12 including a mesh screen disposed between said gas separator and said injector for further distributing said first and second gases.

18. The reactor of claim 12 wherein said injector includes a plurality of gas passages for said first and second gases.

19. The reactor of claim 18 wherein said injector includes a cooling passage for cooling said first gas and second gases passing through said plurality of gas passages.

20. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a first gas inlet, a second gas inlet, a carrier gas inlet, an injector for injecting said first and second gases and said carrier gas into said reactor chamber towards said substrate carrier in a first direction, and a gas separator for separately maintaining said first and second gases and said carrier gas between said gas inlet and said injector and for separately distributing said first and second gases and said carrier gas within a single plane transverse to said first direction and over the surface of said injector whereby said first and second gases and said carrier gas are separately maintained after said first and second gases and said carrier gas have exited from said injector towards said substrate carrier with said carrier gas disposed between said first and second gases.

21. The reactor of claim 20 including a mesh screen disposed between said gas separator and said injector for further distributing said first and second gases.

22. The reactor of claim 20 wherein said gas separator includes a first gas chamber for said first gas, a second gas chamber for said second gas, and a carrier gas chamber for said carrier gas.

23. The reactor of claim 20 wherein said gas separator includes first and second gas receiving portions for receiving said first and second gases from said first and second gas inlets, first and second gas chambers for distributing a quantity of said first and second gases prior to entry into said injector, and wall means separating said first and second gas receiving portions from said first and second gas chambers, said wall means including an aperture for permitting said first and second gases to pass from said first and second gas receiving portions to said first and second gas chambers.

24. The reactor of claim 23 wherein said first and second gas chambers have a configuration defining an arc of a circle.

25. The reactor of claim 20 wherein said injector includes a plurality of gas passages for said first and second gases.

26. The reactor of claim 25 wherein said injector includes a cooling passage for cooling said first and second gases passing through said plurality of gas passages.

27. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber toward said substrate carrier, said substrate carrier comprising a substantially enclosed rotatable shell defining an inner space, said rotatable shell including an upper end facing said injector, and including a removable substrate support mounted on said upper end of said rotatable shell for rotation therewith so as to provide an upper end wall for said rotatable shell and thereby creating said substantially enclosed inner space, and a heater for heating said substrate carrier, said heater being disposed within said rotatable shell, said reactor chamber including an access port for gaining access to said inner space defined by said rotatable shell whereby said heater can be accessed and removed through said access port.

28. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a gas inlet, and an injector for injecting said gas into said reactor chamber towards said substrate carrier, said injector including a plurality of coolant passages extending across said injector and a plurality of longitudinally extending gas apertures comprising a plurality of elongated slots extending across said injector and alternating with said plurality of coolant passages, whereby said gas is cooled by at least two of said coolant passages as it passes through at least one of said plurality of longitudinally extending gas apertures into said reactor chamber.

29. The reactor of claim 28 wherein said plurality of coolant passages comprises a plurality of tubular conduits arranged in a parallel array.

30. The reactor of claim 29 wherein said plurality of longitudinally extending elongated slots are arranged in parallel array.

31. The reactor of claim 29 including connecting passages for connecting at least two of said plurality of tubular conduits whereby said coolant can flow continuously therethrough.

32. The reactor of claim 28 wherein said plurality of coolant passages comprises a plurality of coolant passage segments, and including a plurality of coolant inlets and a plurality of coolant outlets, whereby said coolant can be separately fed to and withdrawn from each of said plurality of coolant segments.

33. The reactor of claim 32 including four of said coolant segments.

34. The reactor of claim 30 wherein said injector includes an inner surface facing said substrate carrier, and said plurality of elongated slots includes a chamfered surface on said inner surface of said injector thereby increasing the cooling effect of said plurality of tubular conduits.

35. The reactor of claim 28 wherein said gas inlet comprises a first gas inlet and including a second gas inlet, and a gas separator for separately maintaining said first and second gases between said gas inlets and said injector, said gas separator including first and second gas chambers for distributing a quantity of said first and second gases prior to entry into said injector.

36. The reactor of claim 35 including a carrier gas inlet, wherein said gas separator includes a third gas chamber between said first and second gas chambers for separately maintaining said carrier gas between said gas inlets and said injector, said injector thereby injecting said carrier gas into said chamber toward said substrate carrier between said first and second gases in order to separate said first and second gases from each other.

37. The reactor of claim 35 wherein said gas separator includes first and second gas receiving portions for receiving said first and second gases from said first and second gas inlets, and wall means separating said first and second gas receiving portions from said first and second gas chambers, said wall means including an aperture for permitting said first and second gases to pass from said first and second gas receiving portions to said first and second gas chambers.

38. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, said substrate carrier having a predetermined diameter, whereby at least one of said substrates can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber toward said substrate carrier, whereby said gas and rotation of said substrate carrier creates a boundary layer of said gas above said rotating substrate carrier having a predetermined height, and a flow restricter mounted within said reactor chamber between said injector and said substrate carrier for restricting the flow of said gas therebetween, said flow restricter having a first end corresponding to said injector and a second end adjacent to said substrate carrier and defining a substantially constant inner diameter from said first end of said flow restricter to a location spaced about 0.5 to 2.0″

from said substrate carrier, said inner diameter substantially corresponding to said predetermined diameter of said substrate carrier.

39. The reactor of claim 38 wherein said flow restricter includes a cooling passage.

40. The reactor of claim 39 wherein said cooling passage comprises a passageway within said flow restricter for flowing a coolant therethrough.

41. The reactor of claim 38 wherein said location proximate to said substrate carrier corresponds to the thickness of a boundary layer generated for the flow of said gas in said reactor.

42. The reactor of claim 41 wherein said inner diameter of said flow restricter at said second end comprises a tapered surface having an increasing diameter in the direction approaching said substrate carrier.

43. The reactor of claim 38 wherein said flow restricter is integral with the walls of said reactor chamber.

44. The reactor of claim 38 wherein said flow restricter includes an inner diameter at said second end greater than said predetermined diameter of said substrate.

45. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby said substrate can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber toward said substrate carrier, a flow restricter mounted within said reactor chamber between said injector and said substrate carrier for restricting the flow of said reactant gas therebetween, said flow restricter having a first end corresponding to said injector and a second end adjacent to said substrate carrier and defining an inner diameter at said first end substantially corresponding to said predetermined diameter of said substrate carrier, said inner diameter of said flow restricter at said first end thereof including substantially the entire length of said flow restricter, said flow restricter further including a cooling chamber, and control means associated with said cooling chamber for reducing recirculation within said reactor.

46. The reactor of claim 45 wherein said cooling chamber comprises a passageway within said flow restricter for flowing a coolant therethrough.

47. The reactor of claim 45 wherein said flow restricter is incorporated into the walls of said reactor chamber.

48. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber toward said substrate carrier, said substrate carrier comprising a substantially enclosed rotatable shell defining an inner space, first pressure means for maintaining a first pressure inside said reactor chamber, second pressure means for maintaining a second pressure inside of said rotatable shell, said first pressure being greater than said second pressure, and a heater for heating said substrate carrier, said heater being disposed within said rotatable shell, said reactor chamber including an access port for gaining access to said inner space defined by said rotatable shell whereby said heater can be accessed and removed through said access port.

49. The reactor of claim 48 wherein said access port a wall of said reactor chamber.

50. The reactor of claim 48 wherein said heater means comprises a radiant heater.

51. The reactor of claim 48 wherein said rotatable shell includes an upper end wall facing said injector, and including a removable substrate support mounted on said upper end wall for rotation therewith.

52. The reactor of claim 48 wherein said rotatable shell includes an upper end facing said injector, and including a removable substrate support mounted on said upper end of said rotatable shell for rotation therewith so as to provide an upper end wall for said rotatable shell and thereby creating said substantially enclosed inner space.

53. The reactor of claim 48 wherein said rotatable shell comprises a material selected from the group consisting of graphite, boron nitride, silicon carbon, molybdenum, and high-temperature superalloys.

54. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least one of said substrates can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber towards said substrate carrier, said substrate carrier comprising a rotatable shell defining an inner space and including an inner surface and an outer surface, rotation means for rotating said rotatable shell within said reactor chamber, and cooler for cooling said reactor chamber, said cooling means including an inner cooling member for cooling said inner surface of said rotatable shell and an outer cooling member for cooling said outer surface of said rotatable shell.

55. The reactor of claim 54 wherein said rotation means comprises a spindle mounted with respect to said rotatable shell, a drive pulley, and a drive belt connecting said drive pulley to said spindle for rotating said rotatable shell.

56. The reactor of claim 55 wherein said spindle includes bearings for rotatably supporting said rotatable shell, whereby said cooler cools said bearings.

57. The reactor of claim 55 wherein said drive pulley comprises a drive belt comprising rubber.

58. A reactor for growing epitaxial layers on a substrate comprising a reactor chamber, a substrate carrier rotatably mounted within said reactor chamber, whereby at least ones of said substrates can be mounted on said substrate carrier, a gas inlet, an injector for injecting said gas into said reactor chamber toward said substrate carrier, said substrate carrier comprising a substantially enclosed rotatable shell defining an inner space, said rotatable shell including an upper end wall facing said injector, and including a removable substrate support mounted on said upper end wall for rotation therewith, and a heater for heating said substrate carrier, said heater being disposed within said rotatable shell, said reactor chamber including an access port for gaining access to said inner space defined by said rotatable shell whereby said heater can be accessed and removed through said access port.