Light Emitting Device Having Pillar Structure with Roughness Surface and the Forming Method Thereof

• US 20100237357A1
• Filed: 03/31/2009
• Published: 09/23/2010
• Est. Priority Date: 03/20/2009
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Huga Optotech Incorporated (Epistar Corporation)
• Inventors: KAO, Lin-Chieh, TSAI, Tzong-Liang
• Granted Patent: US 7,999,273 B2
• Time in Patent Office: Days
• US Class Current: 257/79
• 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 33/42 Transparent materials

Abstract

A light emitting device is provided which includes a substrate, a first semiconductor layer having a first region and a second region on the substrate; ac active layer is formed on the first region of the first semiconductor layer; a second semiconductor layer is formed on the active surface layer and the portion surface of the second semiconductor layer is a rough surface; a plurality of pillar structures with a hollow structure, and both of the outer surface and inner surface of the pillar structures are rough surface; a transparent conductive layer is formed to cover the plurality of pillar structures; a first electrode is formed on the transparent conductive layer; and a second electrode is formed on the second region of the first semiconductor layer.

Claims

1. A light emitting device, comprising:

a substrate;

a first semiconductor layer, formed on said substrate thereon, and said first semiconductor layer having a first region and a second region;

an active layer, formed on said first region of said first semiconductor layer;

a second semiconductor layer, formed on said active layer, and said second semiconductor layer having a plurality of pillar structures with a hollow structure therein; and

a transparent conductive layer covering said plurality of pillar structures with said hollow structure therein.

2. The light emitting device according to claim 1, wherein each said depth of said hollow structure of each said plurality of pillar structures is identical, and said depth is selected from the group consisting of from said second semiconductor layer downward to an arbitrary depth of said second semiconductor layer therein, from said second semiconductor layer downward to an arbitrary depth of said active layer;

from said second semiconductor layer downward to expose a surface of said active layer;

from said second semiconductor layer downward through said active layer to expose said first semiconductor layer, and from said second semiconductor layer downward through said active layer to an arbitrary depth of said first semiconductor layer.

3. The light emitting device according to claim 1, wherein each said depth of said hollow structure of each said plurality of pillar structures is different, and said depth is selected from the group consisting of from said second semiconductor layer downward to an arbitrary depth of said second semiconductor layer therein, from said second semiconductor layer downward to an arbitrary depth of said active layer;

from said second semiconductor layer downward to expose a surface of said active layer, from said second semiconductor layer downward through said active layer to expose said first semiconductor layer, and from said second semiconductor layer downward through said active layer to an arbitrary depth of said first semiconductor layer.

4. The light emitting device according to claim 1, further comprising a portion surface of said second semiconductor layer is a rough surface.

5. The light emitting device according to claim 1, further comprising an inner surface and an outer surface of said hollow structure is a rough surface.

6. The light emitting device according to claim 1, further comprising a first electrode disposed on said second region of said first semiconductor layer.

7. The light emitting device according to claim 1, further comprising a second electrode disposed on said transparent conductive layer.

8. The light emitting device according to claim 1, wherein a portion surface of said second semiconductor layer is exposed from said transparent conductive layer.

9. The light emitting device according to claim 8, further comprising a second electrode disposed on said exposed portion surface of said second semiconductor layer and contacted with said transparent conductive layer.

10. A light emitting device, comprising:

a substrate;

a first semiconductor layer, formed on a surface of said substrate;

an active layer, formed on said first semiconductor layer;

a second semiconductor layer, formed on said active layer and said second semiconductor layer having a plurality of pillar structures with hollow structure therein; and

a transparent conductive layer covering said plurality of pillar structures with said hollow structure therein.

11. The light emitting device according to claim 10, wherein each depth of said hollow structure of each said plurality of pillar structures is identical, and said depth is selected from the group consisting of from said second semiconductor layer downward to an arbitrary depth of said second semiconductor layer therein, from said second semiconductor layer downward to an arbitrary depth of said active layer;

from said second semiconductor layer downward to expose a surface of said active layer;

from said second semiconductor layer downward through said active layer to expose said first semiconductor layer, and from said second semiconductor layer downward through said active layer to an arbitrary depth of said first semiconductor layer.

12. The light emitting device according to claim 10, wherein each depth of said hollow structure of each said plurality of pillar structures is different, and said depth is selected from the group consisting of from said second semiconductor layer downward to an arbitrary depth of said second semiconductor layer therein, from said second semiconductor layer downward to an arbitrary depth of said active layer;

from said second semiconductor layer downward to expose a surface of said active layer;

from said second semiconductor layer downward through said active layer to expose said first semiconductor layer, and from said second semiconductor layer downward through said active layer to an arbitrary depth of said first semiconductor layer.

13. The light emitting device according to claim 10, further comprising a portion surface of said second semiconductor layer is a rough surface.

14. The light emitting device according to claim 10, further comprising an inner surface and an outer surface of said hollow structure is a rough surface.

15. The light emitting device according to claim 10, further comprising a first electrode disposed under a bottom surface of said substrate.

16. The light emitting device according to claim 10, further comprising a second electrode disposed on said transparent conductive layer.

17. The light emitting device according to claim 10, wherein a portion surface of said second semiconductor layer is exposed from said transparent conductive layer.

18. The light emitting device according to claim 17, further comprising a second electrode disposed on said exposed portion surface of said second semiconductor layer and contacted with said transparent conductive layer.