Method of fabricating a distributed Bragg reflector having enhanced thermal and electrical properties

• US 6,631,154 B2
• Filed: 08/21/2001
• Issued: 10/07/2003
• Est. Priority Date: 08/22/2000
• Status: Expired due to Fees

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Almuneau, Guilhem, Coldren, Larry A.
• Primary Examiner(s): DAVIE, JAMES W
• Application Number:
  US09/935,000
• Publication Number:
  US 20020024988A1
• Time in Patent Office: 777 Days
• Field of Search: 372/45, 372/46, 372/96, 438/22, 438/29
• US Class Current: 372/96
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 5/02461 Structure or details of the laser chip to manipulate the heat flow, e.g. passive layers in the chip with a low heat conductivity
• CPC Class Codes: H01S 5/18305 with emission through the substrate, i.e. bottom emission
• CPC Class Codes: H01S 5/18316 Airgap confined
• CPC Class Codes: H01S 5/18344 characterized by the mesa, e.g. dimensions or shape of the mesa
• CPC Class Codes: H01S 5/305 characterised by the doping materials used in the laser structure
• CPC Class Codes: H01S 5/3095 Tunnel junction
• CPC Class Codes: H01S 5/34306 emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers

Abstract

A distributed Bragg reflector (DBR) for a vertical cavity surface emitting laser (VCSEL) includes alternating layers of different semiconductor materials to improve thermal and electrical characteristics for the VCSEL. Use of particular materials reduces the thermal resistivity of the DBR and allows heat to dissipate quickly during operation of the VCSEL.

Claims

1. A method of enhancing thermal properties of a distributed Bragg reflector, comprising:

growing a high refractive index layer including aluminum gallium arsenic antimonide (AlGaAsSb) on a substrate; and

growing a low refractive index layer including indium phosphide (InP) on the substrate, the high refractive index layer being lattice-matched to the low refractive index layer to form a layered semiconductor material, wherein use of InP reduces thermal resistivity in the layered semiconductor material.

2. The method of claim 1, wherein the layered semiconductor material forms a reflective device.

3. The method of claim 1, wherein the substrate is InP.

4. The method of claim 1, wherein the layers are comprised of alternating layer pairs of Al_aGa_1-aAs_bSb_1-b which are approximately lattice-matched to InP, and where “

a” and

“

b”

indicate relative proportions of atoms.

5. The method of claim 4, wherein “

a”

is greater than 0.9 and less than 0.9 in alternating layers.

6. The method of claim 4, wherein “

a”

is less than 0.3 and greater than 0.3 in alternating layers.

7. The method of claim 4, wherein “

a”

is less than 0.3 and greater than 0.9 in alternating layers.

8. The method of claim 4, wherein “

a”

is less than 0.3 in alternating layers and “

a”

is large enough such that the layer is substantially transparent to lasing light.

9. The method of claim 3, wherein a first layer of AlGaAsSb is lattice-matched to the InP substrate.

10. The method of claim 1, further comprising doping the layered semiconductor material with tellurium.

11. The method of claim 1, wherein the use of InP increases electrical conductivity of the multi-layered semiconductor material.

12. The method of claim 1, further comprising a plurality of AlGaAsSb layers and a plurality of InP layers, the plurality of AlGaAsSb layers and the plurality of InP layers forming the layered semiconductor material.

13. The method of claim 1, wherein the InP layer and the AlGaAsSb layer are grown on the substrate using solid state molecular beam epitaxy.

14. The method of claim 13, further comprising doping the layered semiconductor material with tellurium (Te) using PbTe as a source material for the molecular beam epitaxy.

15. A method of fabricating a distributed Bragg reflector, comprising:

providing a substrate, a high refractive index aluminum gallium arsenic antimonide (AlGaAsSb) layer of semiconductor material and a low refractive index, indium phospide (InP) layer of semiconductor material; and

growing the AlGaAsSb layer and the InP layer on the substrate to form a reflective device.

16. The method of claim 15, wherein the high refractive index layer is lattice-matched to the low refractive index layer to form a layered semiconductor material.

17. The method of claim 15, wherein the substrate is InP.

18. The method of claim 15, wherein the layers are comprised of alternating layer pairs of Al_aGa_1-aAs_bSb_1-b which are approximately lattice-matched to InP, and where “

a” and

“

b”

indicate relative proportions of atoms.

19. The method of claim 18, wherein “

a”

is greater than 0.9 and less than 0.9 in alternating layers.

20. The method of claim 18, wherein “

a”

is less than 0.3 and greater than 0.3 in alternating layers.

21. The method of claim 18, wherein “

a”

is less than 0.3 and greater than 0.9 in alternating layers.

22. The method of claim 18, wherein “

a”

is less than 0.3 in alternating layers and “

a”

is large enough such that the layer is substantially transparent to lasing light.

23. The method of claim 17, wherein a first layer of AlGaAsSb is lattice-matched to the InP substrate.

24. The method of claim 16, further comprising doping the layered semiconductor material with tellurium.

25. The method of claim 16, wherein the use of InP decreases thermal resistivity of the layered semiconductor material.

26. The method of claim 16, wherein the use of InP increases electrical conductivity of the layered semiconductor material.

27. The method of claim 15, further comprising a plurality of AlGaAsSb layers and a plurality of InP layers, the plurality of AlGaAsSb layers lattice-matched to the plurality of InP layers to form a layered semiconductor material, wherein growing the plurality of AlGaAsSb layers and the plurality of InP layers forms a reflective device.

28. The method of claim 15, further comprising growing the InP layer and the AlGaAsSb layer using solid state molecular beam epitaxy.

29. A distributed Bragg reflector for use in a vertical cavity surface emitting laser, comprising a layered semiconductor material on a substrate, the layered semiconductor material having at least one indium phosphide (InP) layer and at least one aluminum gallium arsenic antimonide (AlGaAsSb) layer lattice-matched to the InP layer.

30. The distributed Bragg reflector of claim 29, wherein the layered semiconductor material forms a reflective device.

31. The distributed Bragg reflector of claim 29, wherein the substrate is InP.

32. The distributed Bragg reflector of claim 29, wherein the layers are comprised of alternating layer pairs of Al_aGa_1-aAs_bSb_1-b which are approximately lattice-matched to InP, and where “

a” and

“

b”

indicate relative proportions of atoms.

33. The distributed Bragg reflector of claim 32, wherein “

a”

is greater than 0.9 and less than 0.9 in alternating layers.

34. The distributed Bragg reflector of claim 32, wherein “

a”

is less than 0.3 and greater than 0.3 in alternating layers.

35. The distributed Bragg reflector of claim 32, wherein “

a”

is less than 0.3 and greater than 0.9 in alternating layers.

36. The distributed Bragg reflector of claim 32, wherein “

a”

is less than 0.3 in alternating layers and “

a”

is large enough such that the layer is substantially transparent to lasing light.

37. The distributed Bragg reflector of claim 31, wherein a first layer of AlGaAsSb is lattice-matched to the InP substrate.

38. The distributed Bragg reflector of claim 29, wherein the layered semiconductor material is N-doped with tellurium.

39. The distributed Bragg reflector of claim 29, further comprising a plurality of AlGaAsSb layers and a plurality of InP layers, the plurality of AlGaAsSb layers lattice-matched to the plurality of InP layers to form the layered semiconductor material, wherein growing the plurality of AlGaAsSb layers and the plurality of InP layers forms a reflective device.

40. The distributed Bragg reflector of claim 39, wherein the layered semiconductor material is N-doped with tellurium.

41. The method of claim 29, wherein the use of InP decreases thermal resistivity of the layered semiconductor material.

42. The method of claim 29, wherein the use of InP increases electrical conductivity of the layered semiconductor material.

43. The distributed Bragg reflector of claim 29, wherein the InP layer and the AlGaAsSb layer are epitaxially grown on the substrate.

44. A method of enhancing thermal properties of a distributed Bragg reflector, comprising:

providing a substrate and a layered semiconductor material grown on the substrate, the layered semiconductor material having a plurality of high refractive index layers each including aluminum gallium arsenic antimonide (AlGaAsSb) and a plurality of low refractive index layers each including indium phosphide (InP); and

reducing thermal resistivity in the layered semiconductor material by lattice-matching the AlGaAsSb layers to the InP layers, wherein the InP layers are introduced into the semiconductor material as the AlGaAsSb layers are grown on the substrate.

45. The method of claim 44, wherein the InP layers and the AlGaAsSb layers are epitaxially grown on the substrate.

46. The method of claim 44, wherein the substrate is InP.

47. The method of claim 45, wherein the layers are comprised of alternating layer pairs of Al_aGa_1-aAs_bSb_1-b which are approximately lattice-matched to InP, and where “

a” and

“

b”

indicate relative proportions of atoms.

48. The method of claim 47, wherein “

a”

is greater than 0.9 and less than 0.9 in alternating layers.

49. The method of claim 47, wherein “

a”

is less than 0.3 and greater than 0.3 in alternating layers.

50. The method of claim 47, wherein “

a”

is less than 0.3 and greater than 0.9 in alternating layers.

51. The method of claim 47, wherein “

a”

is less than 0.3 in alternating layers and “

a”

is large enough such that the layer is substantially transparent to lasing light.

52. The method of claim 46, wherein a first layer of AlGaAsSb is lattice-matched to the InP substrate.

53. The method of claim 44, wherein the layered semiconductor material forms a reflective device.

54. The method of claim 44, further comprising doping the layered semiconductor material with tellurium.

55. The method of claim 44, wherein the use of InP layers decreases thermal resistivity of the layered semiconductor material.

56. The method of claim 44, wherein the use of InP layers increases electrical conductivity of the layered semiconductor material.

57. A distributed Bragg reflector for use in a vertical cavity surface emitting laser, comprising a layered semiconductor material on a substrate, the layered semiconductor material having a binary alloy including at least one indium phosphide (InP) layer and a quarternary alloy including at least one aluminum gallium arsenic antimonide (AlGaAsSb) layer lattice-matched to at least one InP layer.