Light emitting devices with textured active layer

• US 9,153,739 B2
• Filed: 03/14/2014
• Issued: 10/06/2015
• Est. Priority Date: 03/09/2010
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: TSMC Solid State Lighting Ltd. (Ennostar, Inc.)
• Inventors: Huang, Hsin-Chieh
• Primary Examiner(s): Schoenholtz, Joseph
• Application Number:
  US14/210,522
• Publication Number:
  US 20140191191A1
• Time in Patent Office: 571 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01L 33/04 with a quantum effect structure or superlattice, e.g. tunnel junction
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/24 of the light emitting region, e.g. non-planar junction

Abstract

A device includes a textured substrate having a trench extending from a top surface of the textured substrate into the textured substrate, wherein the trench comprises a sidewall and a bottom. A light-emitting device (LED) includes an active layer over the textured substrate. The active layer has a first portion parallel to the sidewall of the trench and a second portion parallel to the bottom of the trench.

Claims

1. A lighting apparatus, comprising:

a substrate that includes a textured surface; and

a light-emitting diode (LED) structure disposed over the textured surface of the substrate;

wherein;

the LED structure includes a first trench and a second trench; and

the first trench and the second trench have different slant angles.

2. The lighting apparatus of claim 1, wherein the first trench and the second trench have different horizontal dimensions.

3. The lighting apparatus of claim 1, wherein the different slant angles are defined by sidewalls of the first trench and the second trench.

4. The lighting apparatus of claim 1, wherein at least one of the first trench and the second trench is shaped as a rectangle in a top view.

5. The lighting apparatus of claim 1, wherein at least one of the first trench and the second trench is shaped as a long strip in a top view.

6. The lighting apparatus of claim 1, wherein the first trench is encircled by the second trench in a top view.

7. The lighting apparatus of claim 1, wherein:

the textured surface of the substrate includes a third trench and a fourth trench;

the first trench is shaped substantially similar to the third trench; and

the second trench is shaped substantially similar to the fourth trench.

8. The lighting apparatus of claim 1, wherein the LED structure is disposed conformally over the textured surface of the substrate.

9. The lighting apparatus of claim 1, wherein the LED structure includes a first cladding layer, a second cladding layer, and a multiple quantum well (MQW) layer disposed between the first and second cladding layers;

and further comprising;

a first electrode disposed on the first cladding layer; and

a second electrode disposed on the second cladding layer.

10. A lighting apparatus, comprising:

a substrate that includes a first trench and a second trench;

a light-emitting diode (LED) structure disposed over the substrate, the LED structure including a first cladding layer, a second cladding layer, and a multiple quantum well (MQW) layer disposed between the first and second cladding layers;

a first electrode electrically coupled to the first cladding layer; and

a second electrode electrically coupled to the second cladding layer;

wherein;

the LED structure includes a third trench disposed over the first trench and a fourth trench disposed over the second trench;

the first trench and the third trench each have a first slant angle; and

the second trench and the fourth trench each have a second slant angle that is different from the first slant angle.

11. The lighting apparatus of claim 10, wherein the first trench and the second trench have different horizontal dimensions.

12. The lighting apparatus of claim 10, wherein the first slant angle is defined by the first trench, and the second slant angle is defined by the second trench.

13. The lighting apparatus of claim 10, wherein at least one of the first trench and the second trench is shaped as a rectangle in a top view.

14. The lighting apparatus of claim 10, wherein at least one of the first trench and the second trench is shaped as a long strip in a top view.

15. The lighting apparatus of claim 10, wherein the first trench is encircled by the second trench in a top view.

16. The lighting apparatus of claim 10, wherein the LED structure is disposed conformally over the substrate.

17. A lighting apparatus, comprising:

a substrate that includes an upper surface that includes a plurality of trenches, wherein the trenches each have sidewalls and a bottom surface, and wherein at least some of the trenches have different slant angles than other trenches, wherein the trenches include a first trench and a second trench being encircled by the first trench in a top view; and

a light-emitting diode (LED) structure disposed conformally over the upper surface of the substrate.

18. The lighting apparatus of claim 17, wherein at least some of the plurality of trenches have different horizontal dimensions from one another.

19. The lighting apparatus of claim 17, wherein at least one of the trenches is shaped as a rectangle or as a long strip in a top view.