Long wavelength VCSEL with tunnel junction, and implant

• US 6,813,293 B2
• Filed: 11/21/2002
• Issued: 11/02/2004
• Est. Priority Date: 11/21/2002
• Status: Expired due to Fees

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Wang, Tzu-Yu, Johnson, Ralph H.
• Primary Examiner(s): Phan, Tho
• Assistant Examiner(s): Flores Ruiz, Delma R.
• Application Number:
  US10/301,380
• Publication Number:
  US 20040101009A1
• Time in Patent Office: 712 Days
• Field of Search: 372/43-50, 372/99
• US Class Current: 372/46.015
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/04257 having positive and negative electrodes on the same side of the substrate
• CPC Class Codes: H01S 5/18308 having a special structure for lateral current or light confinement
• CPC Class Codes: H01S 5/18311 using selective oxidation
• CPC Class Codes: H01S 5/18316 Airgap confined
• CPC Class Codes: H01S 5/1833 with more than one structure
• CPC Class Codes: H01S 5/18369 based on dielectric materials
• CPC Class Codes: H01S 5/18377 comprising layers of different kind of materials, e.g. combinations of semiconducting with dielectric or metallic layers
• CPC Class Codes: H01S 5/2063 obtained by particle bombardment
• CPC Class Codes: H01S 5/3095 Tunnel junction

Abstract

A vertical cavity emitting laser (VCSEL) having a tunnel junction. The junction may be isolated with an implant into a top mirror and past the junction and p-layer. A trench around the VCSEL may result in reduced capacitance and more D.C. isolation of the junction. The implant may occur after the trench is made. Some implant may pass the trench to a bottom mirror. Additional isolation and current confinement may be provided with lateral oxidation of a layer below the junction. Internal trenches may be made from the top of the VCSEL vertically to an oxidizable layer below the junction. For further isolation, an open trench may be placed around a bonding pad and its bridge to the VCSEL and internal vertical trenches may be placed on the pad and its bridge down to the oxidizable layer.

Claims

1. A VCSEL comprising:

a substrate;

a first mirror above said substrate;

an active region above said first mirror;

a tunnel junction above said active region;

a second mirror above said tunnel junction; and

an isolation implant in a portion of said second mirror, tunnel junction and active region.

2. The VCSEL of claim 1, having an island that comprises said active region, tunnel junction and second mirror.

3. The VCSEL of claim 2, wherein the island substantially isolates said tunnel junction.

4. The VCSEL of claim 1, wherein a trench is situated around a significant portion of said active region, tunnel junction and second mirror.

5. The VCSEL of claim 4, wherein the trench substantially isolates said tunnel junction.

6. The VCSEL of claim 2, wherein the island further comprises a bond pad.

7. The VCSEL of claim 4, wherein the trench is further situated around a substantial portion of the bond pad.

8. The VCSEL of claim 2, wherein said first and second mirrors are N-doped mirrors.

9. The VCSEL of claim 4, wherein said first and second mirrors are N-doped mirrors.

10. The VCSEL of claim 8, further comprising a P-doped region.

11. The VCSEL of claim 10, wherein a peripheral portion of said P-doped region is oxidized.

12. The VCSEL of claim 11, further comprising a plurality of vertical internal trenches.

13. The VCSEL of claim 9, further comprising a P-doped region.

14. The VCSEL of claim 13, wherein a peripheral portion of said P-doped region is oxidized.

15. The VCSEL of claim 14, further comprising a plurality of vertical internal trenches.

16. A VCSEL comprising:

a substrate;

a first mirror above said substrate;

an active region above said first mirror;

an island isolated tunnel junction above said active region;

a second mirror above said tunnel junction;

a buried isolation implant in a portion of said first mirror, tunnel junction, and active region; and

a third mirror above a first portion of said second mirror.

17. The VCSEL of claim 16, further comprising at least one layer between said island isolated tunnel junction and active region, wherein said at least one layer is substantially oxidized about its peripheral region.

18. The VCSEL of claim 17, further comprising a plurality of vertical internal trenches.

19. The VCSEL of claim 18 further comprising a conductive contact above a second portion of said second mirror.

20. A VCSEL comprising:

a first mirror;

an active region above said mirror;

an oxide region above said active region; and

a second mirror above said oxide region;

a trench extending through said second mirror, said oxide region and at least part of said active region, said trench having a bottom; and

an isolation implant region extending down from the bottom of the trench.

21. The VCSEL of claim 20, wherein said first mirror is above a substrate.

22. The VCSEL of claim 21, wherein said second mirror, said oxide region and at least part of said active region form an island.

23. The VCSEL of claim 22, wherein said second mirror has an isolation implant in a peripheral portion.

24. The VCSEL of claim 23, further comprising a conductive contact formed above said second mirror.

25. The VCSEL of claim 24, wherein said first and second mirrors are N-doped.

26. The VCSEL of claim 25, wherein said active region has at least one quantum well.

27. The VCSEL of claim 26, wherein said first mirror has an isolation implant in a peripheral portion beyond said island and extending from the bottom of the trench.

28. The VCSEL of claim 27, further comprising a conductive pad having a connection said conductive contact.

29. The VCSEL of claim 28, wherein said conductive pad is on a material at a level of a top of said island.

30. The VCSEL of claim 21, further comprising a tunnel junction above said active region, and said trench also extends through said tunnel junction.

31. The VCSEL of claim 30, wherein said second mirror has an isolation implant in a peripheral portion.

32. The VCSEL of claim 31, wherein said first and second mirrors are N-doped.

33. The VCSEL of claim 32, wherein said oxide region is P-doped.

34. The VCSEL of claim 33, wherein said oxide region has oxidized material in a peripheral portion of said oxide region.

35. The VCSEL of claim 34, wherein said active region has at least one quantum well.

36. The VCSEL of claim 35, further comprising a conductive contact on a peripheral portion of a top surface of said second mirror.

37. The VCSEL of claim 36, further comprising a conductive pad having a bridge connected to said conductive contact.

38. The VCSEL of claim 37 including a trench that extends around a portion of a periphery of said conductive pad and bridge.

39. The VCSEL of claim 38, wherein said conductive pad and bridge are above an isolation implanted material of said second mirror.

40. The VCSEL of claim 39, wherein said bridge is above a planarizing material over a portion of the trench at the periphery of said first mirror, said tunnel junction, said oxide region and said active region.

41. The VCSEL of claim 39, wherein said conductive pad and bridge are above a dielectric material.

42. The VCSEL of claim 39, including at least one trench through said second mirror, said tunnel junction and at least said oxide region within the peripheral portion of the isolation implant.

43. The VCSEL of claim 39 including a plurality of trenches through said conductive pad and bridge, material of said second mirror, tunnel diode and oxide region.

44. A VCSEL comprising:

a first mirror;

an active region above said first mirror;

an oxidation region above said active region;

a tunnel junction above said oxidation region;

a first part of a second mirror above said tunnel junction;

an implant on a peripheral portion of the first part of said second mirror, said tunnel junction, and at least part of said active region; and

a second part of said second mirror above the first part of said second mirror.

45. The VCSEL of claim 44, wherein said first and second mirrors are n-doped.

46. The VCSEL of claim 45, wherein said oxidation layer is P-doped.

47. The VCSEL of claim 46, wherein the second part of said second mirror forms a island above the first part of said second mirror.

49. The VCSEL of claim 47, wherein a peripheral trench at least partially surrounds the first part of said second mirror and said tunnel junction.

55. The VCSEL of claim 49, further comprising a conductive contact above the first part of said second mirror.

56. The VCSEL of claim 55, further comprising:

a conductive pad; and

a bridge connecting said conductive pad to said conductive contact.

57. The VCSEL of claim 56, wherein said conductive pad and bridge are above an implanted material.

58. The VCSEL of claim 57, wherein a dielectric material is situated between said conductive pad and the implanted material and between said bridge and the implanted material.

59. The VCSEL of claim 58, further comprising a plurality of vertical trenches in said conductive pad and bridge, wherein each of said vertical trenches goes from said conductive pad and bridge to an oxidation layer.

60. The VCSEL of claim 59, wherein said peripheral trench is planarized with a material.

61. The VCSEL of claim 60, further comprising at least one vertical trench through at least a portion of said second mirror, said tunnel junction and said oxidation layer.

48. The VCSEL of clam 47, wherein said active region, oxidation region, tunnel junction and second mirror form an island.

50. The VCSEL of claim 48, further comprising a conductive contact above the first part of said second mirror.

51. The VCSEL of claim 50, further comprising:

a conductive pad; and

a bridge connecting said conductive pad to said conductive contact.

52. The VCSEL of claim 51, wherein said conductive pad and bridge are on a planarized material.

53. The VCSEL of claim 52, wherein the planarized material is above an isolation implanted material.

54. The VCSEL of claim 53 further comprising at least one vertical trench through at least a portion of said second mirror, said tunnel junction and said oxidation region.

62. A VCSEL comprising:

first means for reflecting;

means for converting current to light above said first means for reflecting;

means for confining with oxidation above said means for converting current to light;

mean for tunneling above said means for confining;

second means for reflecting above said means for tunneling; and

mean for implant isolating in at least a portion of the periphery of said means for converting current to light.

63. The VCSEL of claim 62, wherein:

said first and second means for reflecting are N-doped; and

said means for confining is P-doped.