Light-emitting devices on textured substrates

• US 9,461,204 B2
• Filed: 03/12/2015
• Issued: 10/04/2016
• Est. Priority Date: 02/12/2010
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Epistar Corporation (Ennostar, Inc.)
• Inventors: Huang, Hsin-Chieh
• Primary Examiner(s): Lee, Jae
• Application Number:
  US14/645,472
• Publication Number:
  US 20150187992A1
• Time in Patent Office: 572 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 33/0066 with a substrate not being a III-V compound
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• 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
• 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

A device includes a textured substrate, which further includes a plurality of trenches. Each of the plurality of trenches includes a first sidewall and a second sidewall opposite the first sidewall. A plurality of reflectors configured to reflect light is formed, with each of the plurality of reflectors being on one of the first sidewalls of the plurality of trenches. The second sidewalls of the plurality of trenches are substantially free from any reflector.

Claims

1. A method, comprising:

forming a plurality of recesses in a first side of a substrate, wherein the recesses each include a first sidewall surface and a second sidewall surface;

forming a reflective layer over the first side of the substrate, wherein the reflective layer are formed on the first and second sidewall surfaces of the recesses;

removing portions of the reflective layer formed on the second sidewall surfaces of the recesses; and

forming a light-emitting diode (LED) on a second side of the substrate, wherein the second side being opposite to the first side.

2. The method of claim 1, wherein the first sidewall surfaces are outer sidewall surfaces, and wherein the second sidewall surfaces are inner sidewall surfaces.

3. The method of claim 1, wherein the forming of the recesses is performed in a manner such that at least some of the recesses have different shapes than other recesses.

4. The method of claim 3, wherein the recesses are formed with different slant angles.

5. The method of claim 1, wherein:

the forming of the recesses is performed in a manner such that each recess further includes a bottom surface that adjoins the first sidewall surface and the second sidewall surface; and

the removing of the portions of the reflective layer is performed such that at least a portion of each of the bottom surface is free of the reflective layer.

6. The method of claim 1, wherein the forming of the recesses is performed such that at least some of the recesses are circumferentially surrounded by other recesses in a top view.

7. The method of claim 6, wherein each of the recesses is a closed loop in the top view.

8. The method of claim 1, wherein the step of forming the light-emitting diode (LED) on a second side of the substrate comprises bonding the second side of the substrate to the light-emitting diode (LED).

9. The method of claim 1, wherein the substrate includes a sapphire substrate, a silicon substrate, a silicon carbide substrate, a silicon germanium substrate, or a substrate containing III-V compound materials.

10. A method, comprising:

forming a plurality of trenches in a substrate, wherein the trenches each extend from a first side of the substrate toward a second side of the substrate opposite the first side, wherein the trenches each include a first sidewall surface, a second sidewall surface, and a bottom surface adjoining the first and second sidewall surfaces;

forming a reflective material in each of the trenches, the reflective material covering the first sidewall surface, the second sidewall surface, and the bottom surface in each of the trenches;

removing portions of the reflective material from each of the trenches in a manner such that the second sidewall surface and at least a portion of the bottom surface in each trench is free of being covered with the reflective material; and

forming a light-emitting diode (LED) on a second side of the substrate, wherein the second side being opposite to the first side.

11. The method of claim 10, wherein the first sidewall surfaces are outer sidewall surfaces, and wherein the second sidewall surfaces are inner sidewall surfaces.

12. The method of claim 10, wherein the forming of the trenches is performed in a manner such that the trenches have different slant angles.

13. The method of claim 10, wherein each of the trenches is a closed loop in a top view, and wherein at least some of the trenches are encircled by at least some other trenches in the top view.

14. The method of claim 10, wherein the step of forming the light-emitting diode (LED) on the second side of the substrate comprises bonding the second side of the substrate to the light-emitting diode (LED).

15. A method of forming a semiconductor device, the method comprising:

providing a substrate;

forming a plurality of trenches extending from a surface of the substrate into the substrate, wherein the plurality of trenches comprises inner sidewalls and outer sidewalls;

forming a reflective layer on the surface of the substrate and on the inner sidewalk and the outer sidewalls;

removing the reflective layer from one of the inner sidewalls of the plurality of trenches; and

forming a light-emitting diode (LED) on a second side of the substrate, wherein the second side being opposite to the first side.

16. The method of claim 15, wherein the step of forming the light-emitting diode on the second side of the substrate comprises bonding the light-emitting diode (LED) onto the substrate, with the plurality of trenches and the light-emitting diode (LED) being on opposite sides of the substrate.

17. The method of claim 15, wherein the step of forming the plurality of trenches comprises laser micro-machining.