High-brightness light emitting diode

• US 6,759,685 B2
• Filed: 09/30/2002
• Issued: 07/06/2004
• Est. Priority Date: 11/07/2001
• Status: Active Grant

• Current Assignee: National Science Council
• Original Assignee: National Chung Hsing University (Government of The Republic of China)
• Inventors: Yang, Juin-Jer, Chung, Chih-Ru, Horng, Ray-Hua, Wu, Tung-Hsing, Huang, Shao-Hua
• Primary Examiner(s): Crane, Sara
• Application Number:
  US10/259,915
• Publication Number:
  US 20030085851A1
• Time in Patent Office: 645 Days
• Field of Search: 257/98, 257/99, 257/94, 257/96, 257/777, 438/118, 438/406, 438/455
• US Class Current: 257/79
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

The present invention discloses a high-brightness light emitting diode (LED), which primarily includes a LED epitaxial layer with a reflective layer and a Si substrate with an adhesive layer. The LED epitaxial layer is bonded with the Si substrate by attaching the reflective layer and the adhesive layer. An n-type ohmic contact electrode and a p-type ohmic contact electrode are deposed on the front side of the LED. In the present invention, the reflective layer, the adhesive layer and the ohmic contact electrodes preferably perform single function, so that the most appropriate materials can be applied. Therefore, the LED of the present invention can exhibit excellent brightness.

Claims

1. A high-brightness light emitting diode, comprising:

an Si substrate;

a first non-reflective adhesive layer formed on said Si substrate;

a non-adhesive reflective layer formed on said first non-reflective adhesive layer and comprising a metal and a non-polymer insulator;

an LED epitaxial layer formed on said non-adhesive reflective layer, having a pn junction structure to define a first-type layer and a second-type layer adjacent to said non-adhesive reflective layer, and having a metal contact layer formed by partial surface of said second-type layer;

a first-type ohmic contact electrode formed on said first-type layer of said LED epitaxial layer; and

a second-type ohmic contact electrode formed on said metal contact layer of said LED epitaxial layer.

2. The high-brightness light emitting diode as claimed in claim 1, wherein said LED epitaxial layer further comprises a p-type confining layer and an n-type confining layer.

3. The high-brightness light emitting diode as claimed in claim 1, wherein said first-type ohmic contact electrode further comprises a transparent electrode thereon.

4. The high-brightness light emitting diode as claimed in claim 1, wherein said non-polymer insulator is adjacent to said LED epitaxial layer.

5. The high-brightness light emitting diode as claimed in claim 1, wherein said metal is selected from the group consisting of Al, Ag, Au, Pt, Pd.

6. The high-brightness light emitting diode as claimed in claim 1, wherein said non-polymer insulator is selected from the group consisting of Al₂O₃, MgF₂, SiO₂, TiO₂ and Si₃N₄.

11. The high-brightness light emitting diode as claimed in claim 1 or 7, wherein said non-adhesive reflective layer further comprises a second non-reflective adhesive layer therebeneath to reinforce attachment with said first non-reflective adhesive layer.

12. The high-brightness light emitting diode as claimed in claim 11, wherein said second non-reflective adhesive layer is a metal.

13. The high-brightness light emitting diode as claimed in claim 12, wherein said metal is selected from the group consisting of Au, Au/Be alloy, Au/Zn alloy, Pt, Pd, Cu, Ni, In and Al.

14. The high-brightness light emitting diode as claimed in claim 1 or 7, wherein said first non-reflective adhesive layer is a metal.

15. The high-brightness light emitting diode as claimed in claim 1 or 7, wherein said first non-reflective adhesive layer is a polymer nonconductor.

7. A high-brightness light emitting diode of non-blue color, comprising:

an Si substrate;

a first non-reflective adhesive layer formed on said Si substrate;

a non-adhesive reflective layer formed on said first non-reflective adhesive layer and comprising a high-dielectric material and a low-dielectric material, wherein said high-dielectric material has a refractive index larger than 2.1, and said low-dielectric material has a refractive index less than 1.56, except for pairs of TiO₂/SiO₂, ZrO₂/SiO₂, Ta₂O₅/SiO₂, HfO₂/SiO₂;

an LED epitaxial layer formed on said reflective layer, having a pn junction structure to define a first-type layer and a second-type layer adjacent to said reflective layer, and having a metal contact layer formed by partial surface of said second-type layer;

a first-type ohmic contact electrode formed on said first-type layer of said LED epitaxial layer; and

a second-type ohmic contact electrode formed on said metal contact layer of said LED epitaxial layer.

8. The high-brightness light emitting diode as claimed in claim 7, wherein said low-dielectric material is adjacent to said LED epitaxial layer.

9. The high-brightness light emitting diode as claimed in claim 7, wherein said high-dielectric material is selected from the group consisting of TiO₂, CeO₂ and Si.

10. The high-brightness light emitting diode as claimed in claim 7, wherein said low-dielectric material is selected from the group consisting of Al₂O₃, MgF₂, SiO₂ and Si₃N₄.