Light emitter device

• US 7,977,687 B2
• Filed: 11/07/2008
• Issued: 07/12/2011
• Est. Priority Date: 05/09/2008
• Status: Active Grant

• Current Assignee: National Chiao Tung University (Government of The Republic of China)
• Original Assignee: National Chiao Tung University (Government of The Republic of China)
• Inventors: Yang, Tsung Hsi, Chang, Chun-Yen
• Primary Examiner(s): Le; Dung A.
• Application Number:
  US12/291,396
• Publication Number:
  US 20090278165A1
• Time in Patent Office: 977 Days
• Field of Search: 257 79- 99, 438/22, 438 48- 55
• US Class Current: 257/88
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/32 containing nitrogen

Abstract

A light emitting device (LED) structure formed on a Group IV-based semiconductor substrate is provided. The LED structure includes a Group IV-based substrate, an AlN nucleation layer formed on the Group IV-based substrate, a GaN epitaxial layer formed on the AlN nucleation layer, a distributed Bragg reflector (DBR) multi-layer structure formed on the epitaxial layer, and an LED active layer formed on the DBR multi-layer structure.

Claims

1. A light emitting device (LED), comprising:

a Group IV-based substrate;

an AlN nucleation layer formed on the Group IV-based substrate;

a GaN epitaxial layer formed on the AlN nucleation layer;

a distributed Bragg reflector (DBR) multi-layer structure formed on the epitaxial layer, wherein the DBR multi-layer structure has a reflective surface having a tilt angle ranged from 5 to 75 degree with respect to a vertical line; and

an LED active layer formed on the DBR multi-layer structure.

2. A light emitting device according to claim 1, further comprising a GaN buffer layer formed between the LED active layer and the DBR multi-layer structure.

3. A light emitting device according to claim 1, wherein the DBR multi-layer structure is made of a nitride comprising a Group III element.

4. A light emitting device according to claim 1, wherein the GaN epitaxial layer is a patterned epitaxial layer.

5. A light emitting device according to claim 1, wherein the DBR multi-layer structure is a patterned multi-layer structure.

6. A light emitting device according to claim 1, wherein the LED active layer further comprises:

an n-type AlGaN layer;

an n-type GaN layer formed on the n-type AlGaN layer;

a multiple quantum wells (MQWs) active layer formed on the n-type GaN layer;

a p-type AlGaN layer formed on the MQWs active layer; and

a p-type GaN layer formed on the p-type AlGaN layer.

7. A light emitting device according to claim 1, wherein the reflective surface has a tilt angle of 64 degree with respect to a vertical line.

8. A light emitting device (LED), comprising:

a substrate having a distributed Bragg reflector (DBR) multi-layer structure, wherein the DBR multi-layer structure has a reflective surface having a tilt angle ranged from 5 to 75 degree with respect to a vertical line;

a GaN buffer layer formed on the substrate; and

an LED active layer formed on the GaN buffer layer.

9. A light emitting device according to claim 8, wherein the substrate further comprises:

a Group IV-based substrate;

a nucleation layer formed on the Group IV-based substrate;

an epitaxial layer formed on the nucleation layer; and

a patterned distributed Bragg reflector (DBR) multi-layer structure formed on the epitaxial layer.

10. A light emitting device according to claim 9, wherein the DBR multi-layer structure is made of a nitride comprising a Group III element.

11. A light emitting device according to claim 9, wherein the nucleation layer is an AlN diffusion barrier layer.

12. A light emitting device according to claim 9, wherein the epitaxial layer is a patterned GaN epitaxial layer.

13. A light emitting device according to claim 8, wherein the LED active layer further comprises:

an n-type AlGaN layer formed on the GaN buffer layer;

an n-type GaN layer formed on the n-type AlGaN layer;

a multiple quantum wells (MQWs) active layer formed on the n-type GaN layer;

a p-type AlGaN layer formed on the MQWs active layer; and

a p-type GaN layer formed on the p-type AlGaN layer.

16. A light emitting device according to claim 8, wherein the reflective surface has a tilt angle of 64 degree with respect to a vertical line.

14. A light emitting device (LED), comprising:

a substrate having a distributed Bragg reflector (DBR) multi-layer structure, and the substrate further comprising;

a Group IV-based substrate;

a nucleation layer formed on the Group IV-based substrate;

an epitaxial layer formed on the nucleation layer; and

a patterned distributed Bragg reflector (DBR) multi-layer structure formed on the epitaxial layer, wherein the DBR multi-layer structure has a reflective surface having a tilt angle ranged from 5 to 75 degree with respect to a vertical line;

a GaN buffer layer formed on the substrate; and

an LED active layer formed on the GaN buffer layer.

15. A light emitting device according to claim 14, wherein the reflective surface has a tilt angle of 64 degree with respect to a vertical line.