Surface plasmon light emitter structure and method of manufacture

• US 20050285128A1
• Filed: 02/09/2005
• Published: 12/29/2005
• Est. Priority Date: 02/10/2004
• Status: Abandoned Application

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Scherer, Axel, Okamoto, Koichi
• Application Number:
  US11/055,005
• Publication Number:
  US 20050285128A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/405 Reflective materials

Abstract

A method (and resulting structures) for manufacturing light emitting semiconductor devices. The method includes providing a substrate comprising a surface region and forming a metal layer overlying the surface region of the substrate. In a specific embodiment, the metal layer and the surface region are characterized by a spatial spacing between the metal layer and the substrate to cause a coupling between electron-hole pairs generated in the substrate and a surface plasmon mode at an interface region between the metal layer and the surface region. Additionally, the interface region has a textured characteristic between the surface region and the metal layer. The textured characteristics causes emission of electromagnetic radiation through the surface plasmon mode or like mechanism according to a specific embodiment.

Claims

1. A light emitting semiconductor device comprising:

a substrate, the substrate comprising a surface region;

a first type semiconductor material overlying the surface region of the substrate;

an active layer overlying the semiconductor material;

a second type semiconductor material overlying the active layer;

a metal layer overlying the second type semiconductor material;

a surface region on the metal layer;

a spatial spacing between the metal layer and the active layer sufficient to cause an energy coupling between a surface plasmon mode at the surface region of the metal layer and the active layer;

a textured interface region between the metal layer and the second type of semiconductor material to enhance formation of electromagetic radiation from the surface plasmon mode;

whereupon the coupling causes an increase of a level of the electromagnetic radiation to be derived from the active layer.

2. The device of claim 1 wherein the active layer comprises a quantum well, the quantum well comprising an emission layer.

3. The device of claim 1 further comprising a textured surface region formed at the textured interface region on the metal layer interfacing the second type semiconductor material.

4. The device of claim 3 wherein the textured surface region is characterized by a roughness.

5. The device of claim 3 wherein the textured surface region is characterized by a plurality of spatial structures.

6. The device of claim 1 wherein the substrate is selected from quartz, silicon, glass, or sapphire.

7. The device of claim 1 wherein the substrate is optically transparent.

8. The device of claim 1 wherein the first semiconductor material is P-type and the second semiconductor material is N-type.

9. The device of claim 1 wherein the first semiconductor material comprises a gallium nitride material.

10. The device of claim 1 wherein the second semiconductor material comprises a gallium nitride material.

11. The device of claim 1 wherein the metal layer comprises a silver bearing material.

12. The device of claim 1 wherein the metal layer comprises a silver bearing material for a preselected wavelength of the electromagnetic radiation.

13. The device of claim 1 wherein the metal layer comprises an aluminum bearing material.

14. The device of claim 1 wherein the metal layer comprises an aluminum bearing material for a preselected wavelength of the electromagnetic radiation.

15. The device of claim 1 wherein the metal layer comprises a gold bearing material.

16. The device of claim 1 wherein the metal layer comprises a gold bearing material for a preselected wavelength of the electromagnetic radiation.

17. The device of claim 1 wherein the textured interface is provided on a portion of the second type of semiconductor material.

18. The device of claim 1 wherein the textured surface is provided on a portion of the metal layer.

20. The device of claim 1 further comprising a first electrode coupled to the first type semiconductor material and a second electrode coupled to the metal layer;

and a voltage potential coupled between the first electrode and the second electrode.

19. The device 1 further comprising an electromagnetic radiation source coupled to the surface region.

21. A method for fabricating light emitting devices comprising:

providing a substrate, the substrate comprising a surface region;

forming a first type semiconductor material overlying the surface region of the substrate;

forming am active layer overlying the semiconductor material;

forming a second type semiconductor material overlying the active layer;

forming a textured interface region between the second type semiconductor material and a metal layer to be formed overlying the second type semiconductor material; and

forming a metal layer including a surface region overlying the second type semiconductor material at a spatial spacing between the surface region and the second type semiconductor material to cause a coupling between a surface plasmon mode at the surface region of the metal layer and the active layer;

whereupon the textured interface region enhances formation of a first electromagnetic radiation to be derived from the surface plasmon mode; and

whereupon the coupling associated with the spatial spacing between the surface region of the metal layer and the second type semiconductor material causes an increase of a level of second electromagnetic radiation to be derived from the active layer.

22. A light emitting semiconductor device comprising:

a substrate comprising a surface region and a semiconductor region;

a metal layer overlying the surface region of the substrate;

an interface region between the surface region and the metal layer;

a textured characteristic at the interface region;

a spatial spacing between the metal layer and the semiconductor region of the substrate to cause a coupling between electron-hole pairs generated in the semiconductor region of the substrate and a surface plasmon mode at the interface region.

23. The device of claim 22 wherein the semiconductor material comprises a semiconductor layer.

24. The device of claim 23 wherein the semiconductor material is selected from a group consisting of Si, Ge, SiC, GaN, InGaN, AlGaN, ZnSe, ZnCdSe, GaAs, AlGaAs, InGaAs, GaP, InGaAlP, AiN, and ZnO.

25. The device of claim 23 wherein the substrate further comprises a dielectric material, the semiconductor material being overlying the dielectric material.

26. The device of claim 25 wherein the dielectric material is selected from a group consisting of glass, quartz, SiO2, SiN, and quartz.

27. The device of claim 22 wherein the substrate comprises a polymer.

28. The device of claim 27 wherein the polymer is at least a molecule doped polymer.

29. The device of claim 22 wherein the first layer comprises a solution.

30. The device of claim 22 wherein the metal layer comprises a metal array.

31. The device of claim 22 wherein the textured surface characteristic enhances electromagnetic radiation to be derived from the surface plasmon mode.

32. The device of claim 22 wherein the substrate comprises a plurality of semiconductor quantum dots.

33. The device of claim 22 wherein the substrate comprises a plurality of active structures, each of the active structures including at least semiconductor quantum dot.

34. The device of claim 22 wherein the substrate comprises a p-type semiconductor layer and an n-type semiconductor layer.

35. The device of claim 22 wherein the substrate comprises a first layer, and overlying active layer, and an overlying second layer.

36. A light emitting semiconductor device comprising:

a first substrate comprising a first surface region;

a first metal layer overlying the first surface region of the first substrate;

a first interface region between the first surface region and the first metal layer;

a first textured characteristic at the first interface region;

a first spatial spacing between the first metal layer and the first substrate to cause a coupling between electron-hole pairs generated in the first substrate and a surface plasmon mode at the first interface region; and

a second substrate comprising a second surface region;

a second metal layer overlying the second surface region of the second substrate;

a second interface region between the second surface region and the second metal layer;

a second textured characteristic at the second interface region;

a second spatial spacing between the second metal layer and the second substrate to cause a coupling between electron-hole pairs generated in the second substrate and a surface plasmon mode at the second interface region.

37. The device of claim 36 further comprising:

an Nth substrate comprising an Nth surface region;

an Nth metal layer overlying the Nth surface region of the Nth substrate;

an Nth interface region between the Nth surface region and the Nth metal layer;

an Nth textured characteristic at the Nth interface region;

an Nth spatial spacing between the Nth metal layer and the Nth substrate to cause a coupling between electron-hole pairs generated in the Nth substrate and a surface plasmon mode at the Nth interface region;

whereupon N is an integer greater than 2.

38. The device of claim 37 wherein the first substrate, the second substrate, and the Nth substrate are arranged in a horizontal stacking configuration.

39. The device of claim 37 wherein the first substrate, the second substrate, and the Nth substrate are arranged in a vertical stacking configuration.

40. A method for manufacturing light emitting semiconductor devices, the method comprising:

providing a substrate comprising a surface region;

forming a metal layer overlying the surface region of the substrate, the metal layer and the surface region being characterized by a spatial spacing between the metal layer and the substrate to cause a coupling between electron-hole pairs generated in the substrate and a surface plasmon mode at an interface region between the metal layer and the surface region;

whereupon the interface region having a textured characteristic between the surface region and the metal layer.

41. The method of claim 40 wherein the metal layer is characterized by an uneven characteristic at the interface region.

42. The method of claim 41 wherein the uneven characteristic having a spatial feature indicative of a roughness and/or grains of the metal layer.

43. The method of claim 40 wherein the textured characteristic comprises a plurality of metal nanostructures.

44. The method of claim 40 wherein the textured characteristic comprises a plurality of metal nanostructures, the plurality of nanostructures being selected from a grating, an nano-array, a pillar array, and other structures.

45. The method of claim 40 further comprising forming a plurality of recessed regions in the surface region to form the textured characteristic at the interface region.

46. The method of claim 40 further comprising forming a plurality of nanostructures to form the textured characteristic at the interface region.

47. A light emitting semiconductor device comprising:

a substrate comprising a surface region, the substrate comprising an active region;

a metal layer overlying the surface region of the substrate;

an interface region between the surface region and the metal layer;

a textured characteristic at the interface region;

a spatial spacing between the metal layer and the active region of the substrate to cause a coupling between electron-hole pairs generated in the substrate and a surface plasmon mode at the interface region;

a first electrode coupled to the substrate;

a second electrode coupled to the metal layer; and

a voltage source coupled between the first electrode and the second electrode to generate electromagnetic radiation in the active region of the substrate, the electromagnetic radiation being enhanced by the coupling between the electron-hole pairs generated by the active region of the substrate and the surface plasmon mode at the interface region.

48. The device of claim 47 wherein the first electrode is transparent.

49. The device of claim 47 wherein the first electrode is overlying a portion of a backside surface of the substrate while maintaining an exposed portion of the backside surface.

50. The device of claim 47 wherein the first electrode is a meshed structure.

51. The device of claim 47 wherein the first electrode comprise a first first electrode structure comprising a plurality of first fingers and a first second electrode structure comprising a plurality of second fingers, the first fingers being interdigitated with the second fingers.

52. The device of claim 47 wherein the first electrode comprises a serpentine structure overlying the surface region.

53. The device of claim 47 wherein the first electrode and the second electrode are separated by a distance sufficient to cause the surface plasmon mode between the first electrode and the second electronde.

54. The device of claim 47 wherein the first electrode and the second electrode are separated by a spatial distance to cause a spatial charge distribution at the first electrode and to cause the surface plasmon mode at the second electrode.