Implantation for current confinement in nitride-based vertical optoelectronics

• US 20030180980A1
• Filed: 12/20/2002
• Published: 09/25/2003
• Est. Priority Date: 12/21/2001
• Status: Abandoned Application

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Nakamura, Shuji, Coldren, Larry A., Margalith, Tal
• Application Number:
  US10/324,878
• Publication Number:
  US 20030180980A1
• Time in Patent Office: Days
• US Class Current: 438/48
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 33/145 with a current-blocking structure
• CPC Class Codes: H01S 2304/12 Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
• CPC Class Codes: H01S 5/0421 characterised by the semiconducting contacting layers electrodes H01S5/0425
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

Ion implantation is used to increase the resistivity of semiconductor device layers for channeling the current through a low resistivity, unimplanted region such that carrier recombination takes place away from regions underneath the contacts. This eliminates absorption of light by the contact thereby providing higher light output power and better current-voltage characteristics to the semiconductor device. The incorporation of a regrown contact layer allows for an undamaged lateral conduction path, and the fabrication of ohmic contacts.

Claims

1. A method for confining current in a semiconductor structure, the method comprising:

selectively disordering a doped nitride based material in a semiconductor structure;

wherein the selective disordering substantially increases the resistance of the material, adjacent a contact, to a current thereby confining the current to a region of substantially low resistance in the doped nitride based material.

2. The method according to claim 1, wherein the selective disordering reduces the emission of light below the contact.

3. The method according to claim 1, wherein the selective disordering of the doped nitride based material is performed by ion implantation.

4. The method according to claim 3, wherein the implantation is done by a species of ions.

5. The method according to claim 4, wherein the weight of the species of ions is larger than the weight of helium ions.

6. The method according to claim 5, wherein the species of ions include aluminum ions.

7. The method according to claim 1, wherein the nitride based material further includes at least one of Gallium (Ga), Indium (In), Aluminum (Al), or Boron (B).

8. The method according to claim 1, wherein the nitride based material is p-doped GaN.

9. A method for confining current in an vertical opto-electronic device, the method comprising:

selectively disordering a doped nitride based material in the vertical opto-electronic device;

wherein the selective disordering substantially increases the resistance of the material, below a contact, to a current thereby confining the current to a region of substantially low resistance in the doped nitride based material.

10. The method according to claim 9, wherein the vertical opto-electronic device is at least one of a VCSEL, LED, and RCLED.

11. The method according to claim 9, wherein the selective disordering reduces the emission of light below the contact.

12. The method according to claim 9, wherein the selective disordering of the doped nitride based material is performed by ion implantation.

13. The method according to claim 12, wherein the implantation is done by a species of ions.

15. The method according to claim 9, wherein the nitride based material further includes at least one of Gallium (Ga), Indium (In), Aluminum (Al), or Boron (B).

16. The method according to claim 9, wherein the nitride based material is p-doped GaN.

14. The method according to claim 14, wherein the species of ions include aluminum ions.

17. A method for reducing the emission of light adjacent a contact of a semiconductor structure, the method comprising:

selectively disordering a doped nitride based material in a semiconductor structure;

wherein the selective disordering substantially increases the resistance of the material, adjacent a contact, to a current thereby reducing the emission of light at the contact.

18. The method according to claim 17, wherein the current is confined to a region of substantially low resistance in the doped nitride based material.

19. The method according to claim 17, wherein the selective disordering of the doped nitride based material is performed by ion implantation.

20. The method according to claim 19, wherein the implantation is done by a species of ions.

21. The method according to claim 20, wherein the weight of the species of ions is larger than the weight of helium ions.

22. The method according to claim 21, wherein the species of ions include aluminum ions.

23. The method according to claim 17, further comprising the step of growing a layer of a substantially conductive doped material on the semiconductor structure.

24. The method according to claim 19, wherein the ion implantation provides means for index guiding of light.

25. The method according to claim 23, further comprising the step of forming contacts for applying the current to the semiconductor structure.

26. The method according to claim 17, wherein the nitride based material further includes at least one of Gallium (Ga), Indium (In), Aluminum (Al), or Boron (B).

27. The method according to claim 17, wherein the nitride based material is p-doped GaN.

28. The method according to claim 17, further comprising the step of masking the semiconductor structure using a masking material.

29. The method according to claim 28, wherein the choice of the masking material is based on at least one of a density and thickness of said masking material to obtain a predetermined amount of implantation stopping distance.

30. The method according to claim 28, wherein the masking material is at least one of Titanium (Ti) or Gold (Au).

31. A method of using ion implantation for providing index wave-guiding of emitted light in a semiconductor structure, the method comprising:

selectively disordering a doped nitride based material in a semiconductor structure using ion implantation;

wherein the ion implantation reduces the refractive index of the disordered and doped nitride based material thereby providing index wave-guiding of emitted light in the semiconductor structure.

32. The method according to claim 31, wherein the disordered and doped nitride based material having lower refractive index surrounds the nitride based material having a higher refractive index.

33. The method according to claim 31, wherein the index wave-guiding of emitted light is due to the lower refractive index material surrounding the higher refractive index material which leads to light guiding along the high refractive index material.

34. The method according to claim 31, wherein the nitride based material further includes at least one of Ga, In, Al, or B.

35. The method according to claim 31, wherein the implantation is done by a species of ions.

36. The method according to claim 35, wherein the weight of the species of ions is larger than the weight of helium ions.

37. The method according to claim 35, wherein the species of ions include Al ions.

38. A method for improving the light output in a vertical cavity surface emitting laser (VCSEL), the method comprising:

removing a portion of a substrate in the VCSEL using etching; and

selectively disordering a doped nitride based material in the VCSEL;

wherein the selective disordering substantially increases the resistance of the material, adjacent at least one contact of the VCSEL, to a current thereby improving the light output in the VCSEL.

39. The method according to claim 38, wherein the current is confined to a region of substantially low resistance in the doped nitride based material.

40. The method according to claim 38, wherein the selective disordering of the doped nitride based material is performed by ion implantation.

41. The method according to claim 40, wherein the implantation is done by a species of ions.

42. The method according to claim 41, wherein the species of ions include aluminum ions.

43. The method according to claim 41, wherein the nitride based material further includes at least one of Gallium (Ga), Indium (In), Aluminum (Al), or Boron (B).

44. The method according to claim 38, wherein the nitride based material is p-doped GaN.

45. The method according to claim 38, further including the step of depositing at least one mirror on the VCSEL.

46. The method according to claim 38, wherein the etching is performed by a photo-electro-chemical (PEC) etching process.

47. A method for improving the light output in a vertical cavity surface emitting laser (VCSEL), the method comprising:

growing a nitride based material on a substrate through lateral epitaxial overgrowth (LEO) process in the VCSEL; and

selectively disordering a p-doped nitride based material in the VCSEL;

wherein the selective disordering substantially increases the resistance of the p-doped material, adjacent at least one contact of the VCSEL, to a current thereby improving the light output in the VCSEL.

48. A semiconductor structure for confining a current, the structure comprising:

a selectively disordered and doped nitride based material;

wherein the selectively disordered material has a substantially higher resistance, adjacent a contact, to a current thereby confining the current to a region of substantially low resistance in the doped nitride based material.

49. The semiconductor structure according to claim 48, wherein the selective disordering of the doped nitride based material is performed by ion implantation.

50. The semiconductor structure according to claim 48, wherein the implantation is done by a species of ions.

51. The semiconductor structure according to claim 49, wherein the species of ions include aluminum ions.

52. The semiconductor structure according to claim 48, further including a layer of a substantially conductive doped material.

53. The semiconductor structure according to claim 48, wherein the ion implantation provides means for index guiding of light.

54. The semiconductor structure according to claim 48, wherein the nitride based material further includes at least one of Gallium (Ga), Indium (In), Aluminum (Al), or Boron (B).

55. The semiconductor structure according to claim 48, wherein the nitride based material is p-doped GaN.