Light-emitting diode device and method of manufacturing the same

• US 6,255,129 B1
• Filed: 09/07/2000
• Issued: 07/03/2001
• Est. Priority Date: 09/07/2000
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Highlink Technology Corp.
• Inventors: Lin, Ming-Der
• Primary Examiner(s): Picardat, Kevin M.
• Application Number:
  US09/658,347
• Time in Patent Office: 299 Days
• Field of Search: 438/25, 438/26, 438/46, 438/29, 438/111, 438/123, 257/81, 257/99, 257/100
• US Class Current: 438/26
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/48465 the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector

Abstract

A light-emitting diode device, such as a blue, green, blue-green light-emitting diode, with a one-wire-bonding characteristic and the method of manufacturing the same have been disclosed. The light-emitting diode device has a GaN-based semiconductor laminated structure formed on an insulating substrate. The GaN-based semiconductor laminated structure includes an n-type layer on its bottom side, a p-type layer on its top side, and an active layer, for generating light, sandwiched between the n-type and p-type layers. An annular isolation portion such as a trench or a high resistivity portion formed by ion implantation is formed in the GaN-based semiconductor laminated structure to separate the p-type layer into a central p-type layer and a peripheral p-type layer and to separate the active layer into a central active layer and a peripheral active layer. A p-type electrode is formed on the central p-type layer without electrically connecting to the peripheral p-type layer. A conductive layer is coated to cover the sidewalls and the bottom surface of the insulating substrate and to ohmically contact with the n-type layer. Preferably, an adhesion layer is sandwiched between the sidewalls and the bottom surface of the insulating substrate and the conductive layer to enhance the adhesive property. According to the present invention, the conductive layer may be formed as a mirror-like reflector or a light-transmissive layer.

Claims

1. A method of manufacturing a light-emitting diode device, comprising the steps of:

preparing an insulating substrate;

forming a first GaN-based semiconductor layer on said insulating substrate;

forming an active layer over said first GaN-based semiconductor layer for generating light;

forming a second GaN-based semiconductor layer over said active layer;

forming an annular isolation portion to separate said second GaN-based semiconductor layer into a central second GaN-based semiconductor layer and a peripheral second GaN-based semiconductor layer and to separate said active layer into a central active layer and a peripheral active layer;

forming a first electrode on said central second GaN-based semiconductor layer without electrically connecting to said peripheral second GaN-based semiconductor layer; and

coating a conductive layer to cover the sidewalls and the bottom surface of said insulating substrate and to ohmically contact with said first GaN-based semiconductor layer.

2. The method of manufacturing a light-emitting diode device according to claim 1, wherein said step of forming said annular isolation portion is to form a trench by means of etching.

3. The method of manufacturing a light-emitting diode device according to claim 1, wherein said step of forming said annular isolation portion is to form a resistivity portion by means of ion implantation.

4. The method of manufacturing a light-emitting diode device according to claim 1, wherein said first GaN-based semiconductor layer is doped as a first conductivity type, said second GaN-based semiconductor layer is doped as a second conductivity type.

5. The method of manufacturing a light-emitting diode device according to claim 4, wherein said first conductivity type is an n-type and said second conductivity type is a p-type.

6. The method of manufacturing a light-emitting diode device according to claim 4, further comprising the steps of:

forming a first conductivity type confining layer on said first GaN-based semiconductor layer; and

forming a second conductivity type confining layer on said active layer,

wherein said step of forming said annular isolation portion is further to separate said first conductivity type confining layer into a central first conductivity type confining layer and a peripheral first conductivity type confining layer and to separate said second conductivity type confining layer into a central second conductivity type confining layer and a peripheral second conductivity type confining layer.

7. The method of manufacturing a light-emitting diode device according to claim 1, further comprising the step of:

forming an adhesion layer on the sidewalls and the bottom surface of said insulating substrate before said step of coating said conductive layer.

8. The method of manufacturing a light-emitting diode device according to claim 1, wherein said conductive layer is formed as a mirror-like reflector.

9. The method of manufacturing a light-emitting diode device according to claim 1, wherein said conductive layer is a layer selected from a group consisting of an indium-tin-oxide layer, a cadmium-tin-oxide layer, a zinc oxide layer, and a thin metal layer, with a thickness in the range from 0.001 μ

m to 1 μ

m, made of a material selected from a group consisting of Au, Ni, Pt, Al, Sn, In, Cr, Ti, and their alloy.

10. The method of manufacturing a light-emitting diode device according to claim 1, wherein said GaN-based semiconductor is a quaternary compound semiconductor of In_xAl_yGa₁₋

x−

yN and the mole fractions x, y satisfy 0≦

x<

1, 0≦

y<

1 and x+y=1.

11. A light-emitting diode device comprising:

an insulating substrate;

a laminated semiconductor structure having a first GaN-based semiconductor layer formed on the top surface of said insulating substrate;

an active layer formed over said first GaN-based semiconductor layer for generating light; and

a second GaN-based semiconductor layer formed over said active layer, wherein an annular isolation portion is formed to separate said second GaN-based semiconductor layer into a central second GaN-based semiconductor layer and a peripheral second GaN-based semiconductor layer and to separate said active layer into a central active layer and a peripheral active layer;

a first electrode formed on said central second GaN-based semiconductor layer without electrically connecting to said peripheral second GaN-based semiconductor layer; and

a conductive layer coated to cover the sidewalls and the bottom surface of said insulating substrate and to ohmically contact with said first GaN-based semiconductor layer.

12. The light-emitting diode device according to claim 11, wherein said annular isolation portion is a trench.

13. The light-emitting diode device according to claim 11, wherein said annular isolation portion is a resistivity portion formed by an ion implantation.

14. The light-emitting diode device according to claim 11, wherein said first GaN-based semiconductor layer is doped as a first conductivity type, while said second GaN-based semiconductor layer is doped as a second conductivity type.

15. The light-emitting diode device according to claim 14, wherein said first conductivity type is an n-type and said second conductivity type is a p-type.

16. The light-emitting diode device according to claim 14, further comprising:

a first confining layer, made of a first conductivity type GaN-based semiconductor material, formed between said first GaN-based semiconductor layer and said active layer and separated into a central first confining layer and a peripheral first confining layer by said annular isolation portion; and

a second confining layer, made of a second conductivity type GaN-based semiconductor material, formed between said active layer and said second GaN-based semiconductor layer and separated into a central second confining layer and a peripheral second confining layer by said annular isolation portion.

17. The light-emitting diode device according to claim 11, further comprising:

an adhesion layer sandwiched between the sidewalls and the bottom surface of said insulating substrate and said conductive layer.

18. The light-emitting diode device according to claim 11, wherein said conductive layer is formed as a mirror-like reflector.

19. The light-emitting diode device according to claim 11, wherein said conductive layer is a layer selected from a group consisting of an indium-tin-oxide layer, a cadmium-tin-oxide layer, a zinc oxide layer, and a thin metal layer, with a thickness in the range from 0.001 μ

m to 1 μ

m, made of a material selected from a group consisting of Au, Ni, Pt, Al, Sn, In, Cr, Ti, and their alloy.

20. The light-emitting diode device according to claim 11, wherein said GaN-based semiconductor is a quaternary compound semiconductor of In_xAl_yGa₁₋

x−

yN and the mole fractions x, y, satisfy 0≦

x<

1, 0≦

y<

1 and x+y=1.