Method for producing p-type group III nitride compound semiconductor

• US 7,041,519 B2
• Filed: 09/22/2003
• Issued: 05/09/2006
• Est. Priority Date: 09/19/2002
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Taki, Tetsuya
• Primary Examiner(s): Nguyen, Tuan H.
• Application Number:
  US10/665,475
• Publication Number:
  US 20040058465A1
• Time in Patent Office: 960 Days
• Field of Search: 438/46, 438/47, 438/22, 438/795
• US Class Current: 438/22
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/2258 Diffusion into or out of AIIIBV compounds
• CPC Class Codes: H01L 21/3245 of AIIIBV compounds
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 2301/173 The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

A second Group III nitride compound semiconductor layer not doped with any impurities or doped with n-type impurities or with n-type and p-type impurities is formed on a first Group III nitride compound semiconductor layer doped with p-type impurities. Resistance is reduced by a heat treatment after or during the formation of the second Group III nitride compound semiconductor layer.

Claims

1. A method of producing p-type Group III nitride compound semiconductor, comprising:

forming a first Group III nitride compound semiconductor layer doped with p-type impurities;

forming a second Group III nitride compound semiconductor layer which is at least one of substantially undoped, doped with n-type impurities, and doped with n-type and p-type impurities, such that an amount of impurities in said second Group III nitride compound semiconductor layer is less than an amount of impurities in said first Group III nitride compound semiconductor layer; and

reducing a resistance one of after and during said forming said second Group III nitride compound semiconductor layer.

2. A method of producing p-type Group III nitride compound semiconductor according to claim 1, further comprising:

removing said second Group III nitride compound semiconductor layer one of after and during said reducing said resistance.

3. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said second Group III nitride compound semiconductor layer has a thickness selected to be in a range of from 1 nm to 100 nm, both inclusively.

4. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said second Group III nitride compound semiconductor layer comprises a thickness which is not less than 1 nm.

5. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said reducing said resistance comprises promoting a diffusion of said p-type impurities in said first Group III nitride compound semiconductor layer to diffuse from interstitial sites in said first Group III nitride compound semiconductor layer.

6. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said reducing said resistance comprises promoting a diffusion of said p-type impurities to diffuse from interstitial sites in said first Group III nitride compound semiconductor layer to said second Group III nitride compound semiconductor layer.

7. A method of producing p-type Group III nitride compound semiconductor according to claim 1, said reducing said resistance comprises desorbing said p-type impurities from said first Group III nitride compound semiconductor layer.

8. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said p-type impurities comprise at least one of magnesium, zinc, beryllium, calcium, strontium and barium.

9. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said n-type impurities comprise at least one of silicon, germanium, carbon, selenium and tellurium.

10. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said reducing said resistance comprises performing a heat treatment using one of electron beam irradiation, laser beam irradiation and oven heating.

11. A method of producing p-type Group III nitride compound semiconductor according to claim 10, wherein said heat treatment is performed in one of a vacuum and a hydrogen-free atmosphere.

12. A method of producing p-type Group III nitride compound semiconductor according to claim 11, wherein said heat treatment comprises heat treating at a temperature of at least 350°

C.

13. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein said forming said first and second Group III nitride compound semiconductor layers comprises sequentially depositing said first and second Group III nitride compound semiconductor layers in a reaction chamber.

14. A method of producing p-type Group III nitride compound semiconductor according to claim 13, wherein said forming said second Group III nitride compound semiconductor layer comprises introducing an n-type impurity source gas to said reaction chamber.

15. A method of producing p-type Group III nitride compound semiconductor according to claim 13, wherein said forming said second Group III nitride compound semiconductor layer comprises introducing an n-type impurity source gas and a p-type impurity source gas to said reaction chamber.

16. A method of producing p-type Group III nitride compound semiconductor according to claim 13, further comprising:

removing said first and second Group III nitride compound semiconductor layers from said reaction chamber, and subjecting said first and second Group III nitride compound semiconductor layers to a heat treatment of greater than 350°

C.

17. A method of producing p-type Group III nitride compound semiconductor according to claim 13, further comprising:

subjecting said first and second Group III nitride compound semiconductor layers to a heat treatment of greater than 350°

C. without removing said first and second Group III nitride compound semiconductor layers from said reaction chamber.

18. A method of producing p-type Group III nitride compound semiconductor according to claim 17, wherein said subjecting said first and second Group III nitride compound semiconductor layers to a heat treatment comprises thermally decomposing said second Group III nitride compound semiconductor layer.

19. A method of producing p-type Group III nitride compound semiconductor according to claim 1, wherein a thickness of said second Group III nitride compound semiconductor layer is no greater than 100 nm.

20. A method of forming a light-emitting diode, comprising:

forming a first Group III nitride compound semiconductor layer doped with p-type impurities;

forming a second Group III nitride compound semiconductor layer on said first Group III nitride compound semiconductor layer such that an amount of impurities in said second Group III nitride compound semiconductor layer is less tan an amount of impurities in said first Group III nitride compound semiconductor layer; and

after a beginning of said forming said second Group III nitride compound semiconductor layer, performing a heat treatment to reduce an electrical resistivity of said first Group III nitride compound semiconductor layer,

wherein said second Group III nitride compound semiconductor layer is at least one of substantially undoped, doped with n-type impurities, and doped with n-type and p-type impurities.