Method for growing p-n heterojunction-based structures utilizing HVPE techniques

• US 6,559,038 B2
• Filed: 05/18/2001
• Issued: 05/06/2003
• Est. Priority Date: 11/18/1997
• Status: Expired due to Term

• Current Assignee: Kyma Technologies, Inc.
• Original Assignee: Technologies And Devices International Inc.
• Inventors: Vassilevski, Konstantin V., Melnik, Yuri V., Dmitriev, Vladimir A., Nikolaev, Audrey E.
• Primary Examiner(s): Meier, Stephen D.
• Assistant Examiner(s): Duong, Khanh
• Application Number:
  US09/860,651
• Publication Number:
  US 20020022286A1
• Time in Patent Office: 718 Days
• Field of Search: 438/518, 438/519, 438/542, 438/546, 438/930, 438/925, 438/920, 438/505, 438/508, 438/46, 438/47, 438/93, 438/94, 438/172, 438/235, 438/183, 438/185, 438/200, 438/201, 438/189, 438/190, 438/196
• US Class Current: 438/518
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/40 AIIIBV compounds wherein A is B, Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: C30B 29/403 AIII-nitrides
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/02378 Silicon carbide
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02543 Phosphides
• CPC Class Codes: H01L 21/02546 Arsenides
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0259 Microstructure
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 31/0304 including, apart from doping materials or other impurities, only AIIIBV compounds
• CPC Class Codes: H01L 31/105 the potential barrier being of the PIN type
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

A method for fabricating p-type, i-type, and n-type III-V compound materials using HVPE techniques is provided. If desired, these materials can be grown directly onto the surface of a substrate without the inclusion of a low temperature buffer layer. By growing multiple layers of differing conductivity, a variety of different device structures can be fabricated including simple p-n homojunction and heterojunction structures as well as more complex structures in which the p-n junction, either homojunction or heterojunction, is interposed between a pair of wide band gap material layers. The provided method can also be used to fabricate a device in which a non-continuous quantum dot layer is grown within the p-n junction. The quantum dot layer is comprised of a plurality of quantum dot regions, each of which is typically between approximately 20 and 30 Angstroms per axis. The quantum dot layer is preferably comprised of Al_xB_yIn_zGa_{1−x−y−z}N, InGaN_1−a−bP_aAs_b, or Al_xB_yIn_zGa_{1−x−y−z}N_1−a−bP_aAs_b.

Claims

1. A method of fabricating a p-n heterojunction device without the inclusion of a low temperature buffer layer, the method utilizing HVPE techniques and comprising the steps of:

locating a first Group III metal in a first source zone of a reaction chamber;

locating a second Group III metal in a second source zone of said reaction chamber;

locating at least one acceptor impurity metal in a third source zone of said reaction chamber;

locating a substrate within a growth zone of said reaction chamber;

heating said substrate to a first temperature, wherein said first temperature is greater than 900°

C.;

heating said first Group III metal to a second temperature;

heating said second Group III metal to a third temperature;

heating said at least one acceptor impurity metal to a fourth temperature;

introducing a halide reaction gas into said first source zone to form a first halide metal compound;

introducing said halide reaction gas into said second source zone to form a second halide metal compound;

transporting said first and second halide metal compounds to said growth zone;

introducing a reaction gas into said growth zone, said reaction gas containing at least one Group V element;

growing a first III-V layer on said substrate, said first III-V layer formed by said reaction gas reacting with said first and second halide metal compounds, wherein said first III-V layer is an n-type III-V layer;

discontinuing said step of transporting said second halide metal compound to said growth zone;

growing a second III-V layer on said first III-V layer, said second III-V layer formed by said reaction gas reacting with said first halide metal compound, wherein said second III-V layer is an n-type III-V layer;

resuming said step of transporting said second halide metal compound to said growth zone;

transporting said at least one acceptor impurity metal to said growth zone; and

growing a third III-V layer on said second III-V layer, said third III-V layer formed by said reaction gas reacting with said first and second halide metal compounds, wherein said third III-V layer contains said at least one acceptor impurity metal, and wherein said third III-V layer is a p-type III-V layer.

2. The method of claim 1, further comprising the steps of:

depositing a first contact on said third III-V layer; and

depositing a second contact on said substrate.

3. The method of claim 1, further comprising the steps of:

discontinuing said step of transporting said second halide metal compound to said growth zone; and

growing a fourth III-V layer on said third III-V layer, said fourth III-V layer formed by said reaction gas reacting with said first halide metal compound, wherein said fourth III-V layer contains said at least one acceptor impurity metal, and wherein said fourth III-V layer is a p-type III-V layer.

4. The method of claim 3, further comprising the steps of:

depositing a first contact on said fourth III-V layer; and

depositing a second contact on said substrate.

5. The method of claim 1, further comprising the steps of:

selecting Ga as said first Group III metal;

selecting Al as said second Group III metal; and

selecting Mg as said at least one acceptor impurity metal.

6. The method of claim 1, further comprising the step of positioning said at least one acceptor impurity metal on a first sapphire boat within said third source zone.

7. The method of claim 6, further comprising the steps of:

positioning said first Group III metal on a second sapphire boat within said first source zone; and

positioning said second Group III metal on a third sapphire boat within said second source zone.

8. The method of claim 6, further comprising the steps of:

positioning said first Group III metal on a second sapphire boat within said first source zone; and

positioning said second Group III metal on a silicon carbide boat within said second source zone.

9. The method of claim 1, further comprising the steps of:

locating a second acceptor impurity metal in a fourth source zone of said reaction chamber;

heating said second acceptor impurity metal to a fifth temperature; and

transporting said second acceptor impurity metal to said growth zone simultaneously with said at least one acceptor impurity metal.

10. The method of claim 9, positioning said second acceptor impurity metal on a sapphire boat within said fourth source zone.

11. The method of claim 9, selecting Zn as said second acceptor impurity metal.

12. The method of claim 1, further comprising the step of pre-filling said reaction chamber with a flowing inert gas.

13. The method of claim 1, wherein said first temperature is within the temperature range of 1000°

C. to 1100°

C.

14. The method of claim 1, wherein said second and third temperatures are within the temperature range of 750°

C. to 1050°

C.

15. The method of claim 1, wherein said fourth temperature is within the temperature range of 450°

C. to 700°

C.

16. The method of claim 1, wherein said fourth temperature is within the temperature range of 550°

C. to 650°

C.

17. The method of claim 1, wherein said fourth temperature is approximately 615°

C.

18. The method of claim 1, further comprising the step of annealing said third III-V layer.

19. The method of claim 18, said annealing step further comprised of the step of heating said third III-V layer to a temperature within the range of 700°

C. to 800°

C., said heating step performed within a nitrogen atmosphere.

20. The method of claim 19, wherein said annealing step is performed for approximately 10 minutes.

21. The method of claim 1, further comprising the step of selecting a transport rate associated with said step of transporting said at least one acceptor impurity metal to said growth zone, wherein said selected transport rate achieves a concentration of said at least one acceptor impurity metal within said third III-V layer of between 10¹⁸ to 10²¹ atoms cm⁻

1.

22. The method of claim 1, further comprising the step of selecting a transport rate associated with said step of transporting said at least one acceptor impurity metal to said growth zone, wherein said selected transport rate achieves a concentration of said at least one acceptor impurity metal within said third III-V layer of between 10¹⁹ to 10²⁰ atoms cm⁻

1.

23. The method of claim 3, further comprising the step of selecting a transport rate associated with said step of transporting said at least one acceptor impurity metal to said growth zone, wherein said selected transport rate achieves a concentration of said at least one acceptor impurity metal within said fourth III-V layer of between 10¹⁸ to 10²¹ atoms cm⁻

3.

24. The method of claim 3, further comprising the step of selecting a transport rate associated with said step of transporting said at least one acceptor impurity metal to said growth zone, wherein said selected transport rate achieves a concentration of said at least one acceptor impurity metal within said fourth III-V layer of between 10¹⁹ to 10²⁰ atoms cm⁻

3.

25. The method of claim 1, further comprising the step of pre-conditioning said reaction chamber.

26. The method of claim 25, wherein said pre-conditioning step is further comprised of saturating said growth zone and said first, second, and third source zones with said at least one acceptor impurity metal.

27. The method of claim 1, further comprising the step of co-doping said third III-V layer with O.

28. The method of claim 3, further comprising the step of co-doping said fourth III-V layer with O.

29. The method of claim 1, further comprising the step of doping said second III-V layer with at least one donor impurity selected from the group of materials consisting of O, Si, Ge, and Sn.

30. The method of claim 1, further comprising the step of etching said substrate, said first Group III metal, said second Group III metal, and said at least one acceptor impurity metal to remove surface contamination, said etching step performed prior said first growing step.

31. The method of claim 30, wherein said etching step is performed prior to said first transporting step.

32. The method of claim 30, wherein said etching step is performed prior to said first heating step.

33. A method of fabricating a p-n heterojunction device without the inclusion of a low temperature buffer layer, the method utilizing HVPE techniques and comprising the steps of:

locating a first Group III metal in a first source zone of a reaction chamber;

locating a second Group III metal in a second source zone of said reaction chamber;

locating at least one acceptor impurity metal in a third source zone of said reaction chamber;

locating a p-type substrate within a growth zone of said reaction chamber;

heating said p-type substrate to a first temperature, wherein said first temperature is greater than 900°

C.;

heating said first Group III metal to a second temperature;

heating said second Group III metal to a third temperature;

heating said at least one acceptor impurity metal to a fourth temperature;

introducing a halide reaction gas into said first source zone to form a first halide metal compound;

introducing said halide reaction gas into said second source zone to form a second halide metal compound;

transporting said first and second halide metal compounds to said growth zone;

transporting said at least one acceptor impurity metal to said growth zone;

introducing a reaction gas into said growth zone, said reaction gas containing at least one Group V element;

growing a first III-V layer on said substrate, said first III-V layer formed by said reaction gas reacting with said first and second halide metal compounds, wherein said first III-V layer contains said at least one acceptor impurity metal, and wherein said first III-V layer is a p-type III-V layer;

discontinuing said step of transporting said second halide metal compound to said growth zone;

growing a second III-V layer on said first III-V layer, said second III-V layer formed by said reaction gas reacting with said first halide metal compound, wherein said second III-V layer contains said at least one acceptor impurity metal, wherein said second III-V layer is a p-type III-V layer;

resuming said step of transporting said second halide metal compound to said growth zone;

discontinuing said step of transporting said at least one acceptor impurity metal to said growth zone; and

growing a third III-V layer on said second III-V layer, said third III-V layer formed by said reaction gas reacting with said first and second halide metal compounds, wherein said third III-V layer is an n-type III-V layer.

34. The method of claim 33, further comprising the steps of:

depositing a first contact on said third III-V layer; and

depositing a second contact on said substrate.

35. The method of claim 33, further comprising the steps of:

discontinuing said step of transporting said second halide metal compound to said growth zone; and

growing a fourth III-V layer on said third III-V layer, said fourth III-V layer formed by said reaction gas reacting with said first halide metal compound, wherein said fourth III-V layer is an n-type III-V layer.

36. The method of claim 35, further comprising the steps of:

depositing a first contact on said fourth III-V layer; and

depositing a second contact on said substrate.