Method of manufacturing surface textured high-efficiency radiating devices and devices obtained therefrom

• US 6,504,180 B1
• Filed: 07/26/1999
• Issued: 01/07/2003
• Est. Priority Date: 07/28/1998
• Status: Expired due to Term

• Current Assignee: Philips Lighting BV (Koninklijke Philips N.V.)
• Original Assignee: Bruseel, IMEC VZW and Vrije Universiteit
• Inventors: Heremans, Paul, Kuijk, Maarten, Windisch, Reiner, Borghs, Gustaaf
• Primary Examiner(s): Tran, Minh Loan
• Application Number:
  US09/360,505
• Time in Patent Office: 1,261 Days
• Field of Search: 257/95, 257/98, 257/99, 257/88, 372/45, 372/46, 372/49
• US Class Current: 257/98
• CPC Class Codes: G02B 6/4224 using visual alignment markings, e.g. index methods
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/4292 the light guide being disconnectable from the opto-electronic element, e.g. mutually self aligning arrangements
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/025 Physical imperfections, e.g. particular concentration or distribution of impurities
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• 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 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/385 the electrode extending at least partially onto a side surface of the semiconductor body
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A device for emitting radiation at a predetermined wavelength is presented. This device has a cavity with an active layer in which said radiation is generated by charge carrier recombination. The edges of the device define the region or space for radiation and/or charge carrier confinement. At least one of the edges of this cavity has a substantially random grating structure. The edge of the device has substantially random grating structure and can extend as at least one edge of a waveguide forming part of this radiation emitting device. The radiation emitting device of the present invention can have a cavity comprising a radiation confinement space that includes confinement features for the charge carriers confining the charge carriers to a subspace being smaller than the radiation confinement space within the cavity. The emitting device can comprise at least two edges forming, in cross-section, a substantially triangular shape. The angle between these two edges is smaller than 45°. At least one of the two edges has a transparent portion. the devices according to the present invention can be arranged in arrays.

Claims

1. A device for emitting radiation at a predetermined wavelength, said device comprising a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said cavity having a radiation confinement space including confinement features for said charge carriers, and said device comprising at least one edge having a substantially random diffraction grating structure.

2. The device as recited in claim 1, wherein the substantially random grating structure is a regular repetition of a random grating.

3. The device as recited in claim 1 further including a waveguide.

4. The device as recited in claim 3, wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending in said active layer.

5. The device as recited in claim 3 wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending in said radiation confinement space.

6. The device as recited in claim 3 wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending to said confinement features for said charge carriers.

7. The device as recited in claim 3 wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending in said cavity.

8. The device as recited in claim 1, wherein said cavity comprises at least one mesa edge for defining said radiation confinement space.

9. The device as recited in claim 1 wherein said radiation confinement space is confining said charge carriers to a subspace being smaller than the radiation confinement space within said cavity.

10. The device as recited in claim 1, having a charge carrier confinement feature made of a dielectric material.

11. The device as recited in claim 10, wherein said charge carrier confinement feature made of a dielectric material is a ring and wherein said device is mounted on a carrier substrate, said carrier substrate preferably being transparent for said radiation and more preferably including a fiber optic face plate.

12. A device for emitting radiation at a predetermined wavelength, said device comprising a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said cavity having a radiation confinement space including confinement features for said charge carriers, said device comprising at least two edges forming in cross-section a substantially triangular shape and an angle between said edges being smaller than 45°

and at least one of said edges having a transparent portion, and at least one of said edges having a substantially random diffraction grating structure.

13. The device as recited in claim 12, wherein one of the two edges of said cavity is transparent for said radiation and one of the two edges is reflective and wherein the edges are at least adjacent or abutting one to another.

14. The device as recited in claim 13, wherein at least one of the two edges has a roughened surface condition.

15. An array of devices for emitting radiation at a predetermined wavelength, wherein each device comprises a cavity with an active layer generating radiation by charge carrier recombination, said cavity having a radiation confinement space including confinement features for said charge carriers and at least one edge having a substantially random diffraction grating structure, and wherein individual devices of said array are individually controllable.

16. The array of devices as recited in claim 15, wherein the individual devices of said array are being defined with a mesa edge, and wherein grooves between the individual devices have a substantially random diffraction grating structure.

17. The array of devices as recited in claim 15, wherein the individual devices have a common anode and a common cathode contact.

18. The array of devices as recited in claim 15, wherein essentially each device has a microlens mounted thereon.

19. The array of devices as recited in claim 15 being mounted on a polymeric foil carrier.

20. The array of devices as recited in claim 19, wherein said polymeric foil further has a radiation converting phosphorous layer thereon, said device emitting thereby light of a different wavelength at a side where the device is mounted to said polymeric foil carrier compared to a side of the device opposite said polymeric foil carrier.

21. A device for emitting radiation at a predetermined wavelength, said device having a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said device including a waveguide and said device comprising at least one edge having a substantially random diffraction grating structure.

22. The device as recited in claim 21, wherein the substantially random grating structure is a regular repetition of a random grating.

23. The device as recited in claim 22, wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending in said active layer.

24. The device as recited in claim 22, wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending in said radiation confinement space.

25. The device as recited in claim 22, wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending to said confinement features for said charge carriers.

26. The device as recited in claim 22, wherein said edge having a substantially random grating structure is extending as at least one edge of said waveguide forming part of said device, and wherein said edge preferably is abutting or extending in said cavity.

27. The device as recited in claim 21 wherein said cavity is having a radiation confinement space including confinement features for said charge carriers.

28. The device as recited in claim 27, wherein said cavity comprises at least one mesa edge for defining said radiation confinement space.

29. The device as recited in claim 27 wherein said radiation confinement space is confining said charge carriers to a subspace being smaller than the radiation confinement space within said cavity.

30. The device as recited in claim 29, having a charge carrier confinement feature made of a dielectric material.

31. The device as recited in claim 30, wherein said charge carrier confinement feature made of a dielectric material is a ring and wherein said device is mounted on a carrier substrate.

32. The device as recited in claim 30, wherein said charge carrier confinement feature made of a dielectric material is a ring, and wherein said device is mounted on a carrier substrate, said carrier substrate being transparent for said radiation.

33. The device as recited in claim 30, wherein said charge carrier confinement feature made of a dielectric material is a ring, and wherein said device is mounted on a carrier substrate, said carrier substrate being transparent for said radiation and including a fiber optic face plate.

34. A device for emitting radiation at a predetermined wavelength, said device having a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said device including a waveguide and said device comprising two edges forming in cross-section a substantially triangular shape and an angle between said edges being smaller than 45°

, at least one of said edges having a transparent portion and at least one edge having a substantially random diffraction grating structure.

35. The device as recited in claim 34, wherein one of the two edges of said cavity is transparent for said radiation and one of the two edges is reflective and wherein the edges are at least adjacent or abutting one to another.

36. The device as recited in claim 35, wherein at least one of the two edges has a roughened surface condition.

37. An array of devices wherein individual devices of said array have a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said individual devices include a waveguide and comprise at least one edge having a substantially random diffraction grating structure, and wherein individual devices of said array are individually controllable.

38. The array of devices as recited in claim 37 having a common anode and a common cathode contact.

39. The array of devices as recited in claim 37, essentially each device having a microlens thereon.

40. The array of devices as recited in claim 37 being mounted on a polymeric foil carrier.

41. An array of devices wherein individual devices of said array have a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said individual devices include a waveguide and comprise at least one edge having a substantially random diffraction grating structure, wherein said individual devices are individually controllable by being defined with a mesa edge, and wherein grooves in between the individual devices have a substantially random diffraction grating structure.

42. An array of devices for emitting radiation at a predetermined wavelength, wherein each device has a cavity with an active layer wherein said radiation is generated by charge carrier recombination, a waveguide and at least one edge having a substantially random diffraction grating structure, and wherein the devices of said array are individually controllable, said array being mounted on a polymeric foil carrier having a radiation converting phosphorous layer mounted thereon, said array emitting thereby light of a different wavelength at a side where the array is mounted to said polymeric foil carrier compared to a side of the array opposite said polymeric foil carrier.

43. A device for emitting radiation at a predetermined wavelength, said device having a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said device comprising at least one edge having a substantially random diffraction grating structure and being mounted on a transparent carrier.

44. A device for emitting radiation at a predetermined wavelength, said device having a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said device comprising at least one edge having a substantially random diffraction grating structure and having at least one reflective edge, at least one of the electrical contacts to said device being through said reflective edge.

45. The device as recited in claim 44 being mounted on a transparant carrier.

46. A device for emitting radiation at a predetermined wavelength, said device comprising at least two edges forming in cross-section a substantially triangular shape and the angle between said edges being smaller than 45°

and at least one of said edges having a transparent portion.

47. The device as recited in claim 46, wherein one of the two edges of said cavity is transparent for said radiation and one of the two edges is reflective and wherein the edges are at least adjacent or abutting one to another.

48. The device as recited in claim 46, wherein at least one of the two edges has a roughened surface condition.

49. An array of devices for emitting radiation at a predetermined wavelength, said devices comprising a cavity with an active layer wherein said radiation is generated by charge carrier recombination, and wherein individual devices of said array are individually controllable and wherein waveguides exist between the individual devices, said waveguides having a substantially random diffraction grating structure.

50. A device for emitting radiation at a predetermined wavelength, said device comprising a cavity with an active layer wherein said radiation is generated by charge carrier recombination, said cavity having a radiation confinement space including confinement features for said charge carriers, and said device comprising at least one edge having diffraction grating structure, wherein the diffraction grating structure has a plurality of differently spaced ridges and valleys.