Light emitting diode

• US 7,863,599 B2
• Filed: 09/03/2008
• Issued: 01/04/2011
• Est. Priority Date: 10/29/2007
• Status: Active Grant

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: Kim, Dae Won, Kal, Dae Sung, Kim, Hwa Mok
• Primary Examiner(s): DANG, TRUNG Q
• Application Number:
  US12/203,762
• Publication Number:
  US 20090108250A1
• Time in Patent Office: 853 Days
• Field of Search: 257/13, 257/E33.068
• US Class Current: 257/13
• CPC Class Codes: H01L 33/105 with a resonant cavity structure
• CPC Class Codes: H01L 33/42 Transparent materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/465 with a resonant cavity structure

Abstract

A light emitting diode (LED) has an n-type semiconductor layer, an active layer, a p-type semiconductor layer, and a transparent electrode layer. The LED includes a tunnel layer interposed between the p-type semiconductor layer and the transparent electrode layer, an opening arranged in the transparent electrode layer so that the tunnel layer is exposed, a distributed Bragg reflector (DBR) arranged in the opening, and an electrode pad arranged on the transparent electrode layer to cover the DBR in the opening.

Claims

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

an n-type semiconductor layer, an active layer, a p-type semiconductor layer, and a transparent electrode layer arranged on a substrate;

a tunnel layer interposed between the p-type semiconductor layer and the transparent electrode layer;

an opening arranged in the transparent electrode layer so that the tunnel layer or the p-type semiconductor layer under the tunnel layer is exposed upward;

a distributed Bragg reflector (DBR) arranged in the opening; and

an electrode pad arranged on the transparent electrode layer to cover the DBR in the opening.

2. The LED of claim 1, wherein a side surface of the electrode pad contacts an inner side surface of the opening, and a lower surface of the electrode pad contacts the DBR.

3. The LED of claim 1, wherein the tunnel layer is an n-type tunnel layer (n++) doped with a highly concentrated n-type impurity.

4. The LED of claim 1, wherein the transparent electrode layer is an indium tin oxide (ITO) layer.

5. The LED of claim 1, further comprising a lower DBR arranged under the active layer.

6. The LED of claim 1, wherein the LED is a GaN-based LED.

7. The LED of claim 1, wherein the DBR comprises low refractive index layers and high refractive index layers alternately laminated.

8. The LED of claim 7, wherein the low refractive index layers comprise SiO₂ or Al₂O₃.

9. The LED of claim 7, wherein the high refractive index layers comprise Si₃N₄, TiO₂, or Si—

H.

10. A light emitting diode (LED), comprising:

an n-type semiconductor layer, an active layer, a p-type semiconductor layer, and a transparent electrode layer arranged on a substrate;

an opening arranged in the transparent electrode layer;

an electrode pad arranged to partially fill the opening; and

an n++ or undoped layer arranged on the transparent electrode layer and contacting the electrode pad.