Methods of making multi-layer light emitting devices

• US 7,083,993 B2
• Filed: 11/26/2003
• Issued: 08/01/2006
• Est. Priority Date: 04/15/2003
• Status: Expired due to Fees

• Current Assignee: Formosa Epitaxy Incorporated (Epistar Corporation)
• Original Assignee: Luminus Devices Incorporated (Sanan Optoelectronics Company Limited)
• Inventors: Graff, John W, Erchak, Alexei A., Brown, Michael Gregory, Duncan, Scott W.
• Primary Examiner(s): Nadav, Ori
• Application Number:
  US10/724,005
• Publication Number:
  US 20040206962A1
• Time in Patent Office: 979 Days
• Field of Search: 438 22- 27, 438/29, 257/79, 257/98, 257/100, 257/103
• US Class Current: 438/25
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate

Abstract

Methods of making multi-layer light-emitting devices and related components and systems are disclosed. The light-emitting devices can include a layer of reflective material bonded with a layer of p-doped material. The reflective material can be capable of reflecting at least about 50% of light generated by a light-generating region that impinges on the layer of reflective material.

Claims

1. A method of making a light-emitting device comprising a multi-layer stack of materials including a layer of p-doped material, a light-generating region, and a first layer, the method comprising:

bonding the first layer with a substrate;

subsequent to bonding the first layer with the substrate, bonding a layer of a reflective material with the layer of p-doped material, the multi-layer stack of materials being between the substrate and the layer of reflective material; and

removing the substrate,

wherein;

the first layer includes a surface having a dielectric function that varies spatially according to a pattern;

the reflective material is capable of reflecting at least about 50% of light generated by the light-generating region that impinges on the layer of reflective material; and

the substrate is removed after bonding the layer of the reflective material with the layer of p-doped material.

2. The method of claim 1, further comprising forming a bonding layer between the first layer and the substrate.

3. The method of claim 1, further comprising lapping and polishing steps after removing the substrate.

4. The method of claim 1, wherein removing the substrate includes heating a bonding layer disposed between the first layer and the substrate.

5. The method of claim 4, wherein heating the bonding layer decomposes at least a portion of the bonding layer.

6. The method of claim 4, wherein heating the bonding layer includes exposing the bonding layer to radiation emitted by a laser.

7. The method of claim 6, wherein removing the substrate includes exposing the substrate using a laser liftoff process.

8. The method of claim 1, wherein removing the substrate results in the surface of the first layer becoming substantially flat.

9. The method of claim 1, further comprising, before forming the pattern in the surface of the first layer, planarizing the surface of the first layer after the first substrate is removed.

10. The method of claim 9, wherein planarizing the surface of the first layer includes chemical-mechanical polishing the surface of the first layer.

11. The method of claim 9, wherein planarizing the surface of the first layer reduces a roughness of the surface of the first layer to greater than about λ

/5, where λ

is a wavelength of light that can be emitted by the first layer.

12. The method of claim 1, further comprising forming the pattern in the surface of the first layer.

13. The method of claim 12, wherein forming the pattern includes using nanolithography.

14. The method of claim 12, wherein the pattern has features that are greater than about λ

/5, where λ

is a wavelength of light that can be emitted by the first layer.

15. The method of claim 1, further comprising disposing a substrate on the layer of reflective material.

16. The method of claim 1, further comprising disposing a current-spreading layer between the first layer and the light-generating region.

17. The method of claim 1, wherein the light-emitting device is selected from the group consisting of light-emitting diodes, lasers, optical amplifiers, and combinations thereof.

18. The method of claim 1, wherein the light-emitting device comprises a light emitting diode.

19. The method of claim 1, wherein the light-emitting device is selected from the group consisting of OLEDs, flat surface-emitting LEDs, HBLEDs, and combinations thereof.

20. A method of making a light-emitting device comprising a multi-layer stack of materials including a layer of p-doped material, a light-generating region, and a first layer, the first layer including a surface having a dielectric function that varies spatially according to a pattern, the method comprising:

bonding the first layer with a substrate;

subsequent to bonding the first layer with the substrate, bonding a layer of a reflective material with the layer of p-doped material, the multi-layer stack of materials being between the substrate and the layer of reflective material;

removing the substrate;

planarizing a surface of the first layer after the substrate is removed; and

before forming the pattern in the surface of the first layer, planarizing the surface of the first layer,

wherein the reflective material is capable of reflecting at least about 50% of light generated by the light-generating region that impinges on the layer of reflective material.

21. The method of claim 20, further comprising forming a bonding layer between the first layer and the substrate.

22. The method of claim 20, wherein planarizing the surface of the first layer includes lapping and polishing steps.

23. The method of claim 20, wherein the substrate is removed after bonding the layer of the reflective material with the first layer.

24. The method of claim 20, wherein removing the substrate includes heating a bonding layer disposed between the first layer and the substrate.

25. The method of claim 24, wherein heating the bonding layer decomposes at least a portion of the bonding layer.

26. The method of claim 24, wherein heating the bonding layer includes exposing the bonding layer to radiation emitted by a laser.

27. The method of claim 26, wherein removing the substrate includes exposing the substrate using a laser liftoff process.

28. The method of claim 20, wherein removing the substrate results in the surface of the first layer becoming substantially flat.

29. The method of claim 20, wherein planarizing the surface of the first layer includes chemical-mechanical polishing the surface of the first layer.

30. The method of claim 20, wherein planarizing the surface of the first layer reduces a roughness of the surface of the first layer to greater than about λ

/5, where λ

is a wavelength of light that can be emitted by the first layer.

31. The method of claim 20, further comprising forming the pattern in the surface of the first layer.

32. The method of claim 31, wherein forming the pattern includes using nanolithography.

33. The method of claim 31, wherein the pattern has features that are greater than about λ

/5, where λ

is a wavelength of light that can be emitted by the first layer.

34. The method of claim 20, further comprising disposing a substrate on the layer of reflective material.

35. The method of claim 20, further comprising disposing a current-spreading layer between the first layer and the light-generating region.

36. The method of claim 20, wherein the light-emitting device is selected from the group consisting of light-emitting diodes, lasers, optical amplifiers, and combinations thereof.

37. The method of claim 20, wherein the light-emitting device comprises a light emitting diode.

38. The method of claim 20, wherein the light-emitting device is selected from the group consisting of OLEDs, flat surface-emitting LEDs, HBLEDs, and combinations thereof.