Textured Light Emitting Devices and Methods of Making the Same

• US 20120241788A1
• Filed: 10/31/2011
• Published: 09/27/2012
• Est. Priority Date: 10/29/2010
• Status: Abandoned Application

• Current Assignee: SiOnyx, LLC (Black Silicon Holdings, Inc.)
• Original Assignee: SiOnyx, LLC (Black Silicon Holdings, Inc.)
• Inventors: Carey, James, Franklin, J. Caleb
• Application Number:
  US13/286,068
• Publication Number:
  US 20120241788A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: B23K 2101/34 Coated articles , e.g. plated or painted; Surface treated articles
• CPC Class Codes: B23K 2101/35 Surface treated articles
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/08 Non-ferrous metals or alloys
• CPC Class Codes: B23K 2103/10 Aluminium or alloys thereof
• CPC Class Codes: B23K 2103/52 Ceramics
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/0624 using ultrashort pulses, i.e. pulses of 1ns or less
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B23K 26/3584 Increasing rugosity, e.g. roughening
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

Light emitting devices having a textured light emission surface and methods are disclosed. A light emitting device can include a semiconductor substrate having a light emission surface, a semiconductive junction and a textured region formed via laser irradiation on the light emission surface. During us of the light emitting device, light generated by the semiconductive junction can primarily emit through the light emission surface having the textured region.

Claims

1. A light emitting device comprising:

a semiconductor substrate having a light emission surface;

a semiconductive junction having a p-type region and an n-type region, wherein the semiconductive junction is operable to emit light primarily through the light emission surface; and

a textured region formed via laser irradiation on the light emission surface, wherein the textured region is operable to diffuse light emitted through the light emission surface.

2. The light emitting device of claim 1, wherein the laser textured region has surface features having a height in the range of about 1 nm to about 4 microns.

3. The light emitting device of claim 2, wherein the surface features have a height in the range of about 10 nm to about 2 microns.

4. The light emitting device of claim 1, further comprising at least one electrical contact disposed on the p-type region.

5. The light emitting device of claim 1, further comprising at least one electrical contact disposed on the n-type region.

6. The light emitting device of claim 1, further comprising a reflective layer positioned to reflect light through the light emission surface.

7. The light emitting device of claim 6, wherein the reflective layer comprises a metallic material.

8. The light emitting device of claim 7, wherein the metallic material is selected from a group consisting of aluminum, silver, tungsten, gold, alloys and combinations thereof.

9. The light emitting device of claim 1, further comprising an encapsulant disposed on the light emission surface.

10. The light emitting device of claim 1, wherein the encapsulant has a refractive index of less than about 1.5.

11. The light emitting device of claim 1, further comprising a textured surface formed via laser irradiation on the substrate surface opposite the light emission surface.

12. The light emitting device of claim 11, wherein the textured surface comprises surface features.

13. The light emitting device of claim 12, wherein the surface features have a size in the range of about 10 nm to about 2 microns.

14. The light emitting device of claim 1, further comprising a growth substrate.

15. The light emitting device of claim 14, wherein the growth substrate is comprised of sapphire.

16. The light emitting device of claim 14, further comprising surface features disposed on a surface between the growth substrate and the semiconductor substrate.

17. The light emitting device of claim 16, wherein the surface features have a height in the range of about 1 nm to about 4 microns.

18. A method of manufacturing a light emitting device comprising:

providing a semiconductor substrate having a light emission surface and at least two doped regions;

irradiating at least a portion of the light emission surface of the semiconductor substrate with laser irradiation to form a textured surface on the light emission surface;

coupling at least one electrical contact to the light emission surface.

19. The method of manufacturing of claim 18, further comprising the step of positioning a reflective layer about the semiconductor substrate to reflect light through the light emission surface.

20. The method of manufacturing of claim 18, further comprising the step of disposing an encapsulant on the light emission surface.

21. The method of manufacturing of claim 18, wherein the laser irradiation has a wavelength in the range of about 200 nm to about 900 nm.

22. The method of manufacturing of claim 18, wherein the laser irradiation is pulsed laser irradiation.

23. The method of manufacturing of claim 22, wherein the pulsed laser irradiation has a pulse duration of about 5 femtoseconds to about 900 picoseconds.

24. The method of manufacturing of claim 18, wherein the laser irradiation has a fluence in the range of about 0.20 J/cm² to about 1 J/cm².

25. The method for manufacturing of claim 18, further comprising annealing the semiconductor substrate after the irradiation step.