High-brightness light emitting diode having reflective layer

• US 20070012937A1
• Filed: 07/12/2005
• Published: 01/18/2007
• Est. Priority Date: 07/12/2005
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Visual Photonics Epitaxy Company Limited
• Inventors: Liu, Jin-Hsiang, Wang, Hui-Heng, Lin, Kun-Chuan
• Granted Patent: US 7,335,924 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/387 with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• CPC Class Codes: H01L 33/405 Reflective materials

Abstract

An LED structure is disclosed herein, which comprises, sequentially arranged in the following order, a light generating structure, a non-alloy ohmic contact layer, a metallic layer, and a substrate. As a reflecting mirror, the metallic layer is made of a pure metal or a metal nitride for achieving superior reflectivity. The non-alloy ohmic contact layer is interposed between the metallic layer and the light generating structure so as to achieve the required ohmic contact. To prevent the metallic layer from intermixing with the non-alloy ohmic contact layer and to maintain the flatness of the reflective surface of the first metallic layer, an optional dielectric layer is interposed between the metallic layer and the non-alloy ohmic contact layer.

Claims

1. A light emitting diode structure having a plurality of layers positioned sequentially from bottom to top, comprising:

a substrate;

a first metallic layer made of one of a pure metal and a metal nitride above said substrate;

a non-alloy ohmic contact layer above said first metallic layer; and

a light generating structure above said non-alloy ohmic contact layer which generates lights in response to the conduction of current through said light emitting diode structure.

2. The light emitting diode structure as claimed in claim 1, wherein said first metallic layer is made of one of the following materials:

Au, Al, Ag, TiN_x, and ZrN_x.

3. The light emitting diode structure as claimed in claim 1 further comprising an optically transparent and electrically conductive first dielectric layer positioned between said first metallic layer and said non-alloy ohmic contact layer.

4. The light emitting diode structure as claimed in claim 3, wherein said first dielectric layer is made of a transparent conductive oxide.

5. The light emitting diode structure as claimed in claim 4, wherein said first dielectric layer is made of one of the following materials:

ITO, IZO, SnO, Antimony-doped SnO, Fluorine-doped SnO, Phosphorus-doped SnO, ZnO, Aluminum-doped ZnO, InO, CdO, CTO, CuAlO, CuCaO, and SrCuO.

6. The light emitting diode structure as claimed in claim 1 further comprising a second metallic layer positioned between said first metallic layer and said substrate.

7. The light emitting diode structure as claimed in claim 6, wherein said second metallic layer is made of one of a pure metal and an alloy metal.

8. The light emitting diode structure as claimed in claim 6 further comprising a second dielectric layer positioned between said first metallic layer and said second metallic layer.

9. The light emitting diode structure as claimed in claim 8, wherein said second dielectric layer is made of one of the following three types of materials:

transparent conductive oxide, metal nitride, and insulating material.

10. The light emitting diode structure as claimed in claim 9, wherein said second dielectric layer is made of one of the following materials:

ITO, IZO, SnO, Antimony-doped SnO, Fluorine-doped SnO, Phosphorus-doped SnO, ZnO, Aluminum-doped ZnO, InO, CdO, CTO, CuAlO, CuCaO, SrCuO, TiN_x, ZrN_x, SiN_x, and SiO_x.

11. The light emitting diode structure as claimed in claim 6 further comprising a third metallic layer positioned between said second metallic layer and said substrate.

12. The light emitting diode structure as claimed in claim 11, wherein said third metallic layer is made of one of a pure metal and an alloy metal.

13. The light emitting diode structure as claimed in claim 1, wherein said non-alloy ohmic contact layer is a doped semiconductor layer.

14. The light emitting diode structure as claimed in claim 13, wherein said non-alloy ohmic contact layer is made of one of the following materials:

carbon-doped AlAs, carbon-doped GaP, carbon-doped AlP, carbon-doped AlGaAs, carbon-doped InAlAs, carbon-doped InGaP, carbon-doped InAlP, carbon-doped AlGaP, carbon-doped GaAsP, carbon-doped AlAsP, carbon-doped AlGaInP, carbon-doped AlGaInAs, carbon-doped InGaAsP, carbon-doped AlGaAsP, carbon-doped AlInAsP, carbon-doped InGaAlAsP, Mg-doped AlAs, Mg-doped GaP, Mg-doped AlP, Mg-doped AlGaAs, Mg-doped InAlAs, Mg-doped InGaP, Mg-doped InAlP, Mg-doped AlGaP, Mg-doped GaAsP, Mg-doped AlAsP, Mg-doped AlGaInP, Mg-doped AlGaInAs, Mg-doped InGaAsP, Mg-doped AlGaAsP, Mg-doped AlInAsP, Mg-doped InGaAlAsP, Zn-doped AlAs, Zn-doped GaP, Zn-doped AlP, Zn-doped AlGaAs, Zn-doped InAlAs, Zn-doped InGaP, Zn-doped InAlP, Zn-doped AlGaP, Zn-doped GaAsP, Zn-doped AlAsP, Zn-doped AlGaInP, Zn-doped AlGaInAs, Zn-doped InGaAsP, Zn-doped AlGaAsP, Zn-doped AlInAsP, Zn-doped InGaAlAsP, carbon-doped InP, carbon-doped InAs, carbon-doped GaAs, carbon-doped InAsP, Mg-doped InP, Mg-doped InAs, Mg-doped GaAs, Mg-doped InAsP, carbon-doped InP, Zn-doped InAs, Zn-doped GaAs, and Zn-doped InAsP.

15. The light emitting diode structure as claimed in claim 1, wherein said non-alloy ohmic contact layer has a plurality of recesses along the interface between said non-alloy ohmic contact layer and said first metallic layer.

16. The light emitting diode structure as claimed in claim 1, wherein said substrate is an electrically conductive substrate.

17. The light emitting diode structure as claimed in claim 16, wherein said substrate is made of one of the following materials:

doped Ge, doped Si, doped GaAs, doped GaP, doped InP, doped InAs, doped GaN, doped AlGaAs, doped SiC, doped GaAsP, Mo, Cu, and Al.

18. The light emitting diode structure as claimed in claim 1 further comprising an insulating layer immediately on top of said substrate for a planar arrangement of electrodes of said light emitting diode structure.

19. The light emitting diode structure as claimed in claim 18, wherein said insulating layer is made of one of the following materials:

SiN_x and SiO_x.

20. The light emitting diode structure as claimed in claim 1, wherein said substrate is a non-electrically conductive substrate.

21. The light emitting diode structure as claimed in claim 20, wherein said substrate is made of one of the following materials:

Ge, Si, GaAs, GaP, InP, InAs, GaN, AlN, AlGaAs, SiC, GaAsP, sapphire, glass, quartz, and ceramic.