Window for gallium nitride light emitting diode

• US 6,420,736 B1
• Filed: 07/26/2000
• Issued: 07/16/2002
• Est. Priority Date: 07/26/2000
• Status: Expired

• Current Assignee: Dalian Lumei Optoelectronics Company Limited (Luming Science and Technology Group)
• Original Assignee: AXT Incorporated
• Inventors: Chen, John, Liang, Bingwen, Shih, Robert
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): HO, TU TU V
• Application Number:
  US09/626,445
• Time in Patent Office: 720 Days
• Field of Search: 257/13, 257/79-103, 438/606
• US Class Current: 257/99
• CPC Class Codes: H01L 33/02 characterised by the semiconductor bodies
• CPC Class Codes: H01L 33/14 with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01L 33/42 Transparent materials

Abstract

A window structure for a gallium nitride (GaN)-based light emitting diode (LED) includes a Mg+ doped p window layer of a GaN compound; a thin, semi-transparent metal contact layer; and an amorphous current spreading layer formed on the contact layer. The contact layer is formed of NiO_x/Au and the current spreading layer is formed of Indium Tin Oxide. The p electrode of the diode includes a titanium adhesion layer which forms an ohmic connection with the current spreading layer and a Schottky diode connection with the Mg+ doped window layer.

Claims

1. A light emitting diode comprising:

a substrate;

a light emitting region;

a window structure; and

first and second electrodes;

wherein said window structure comprises;

a semi-transparent metal contact layer, and

a semi-transparent, conductive amorphous current spreading layer formed directly on an exposed face of said contact layer; and

wherein an opening is formed through said contact layer and said current spreading layer and said first electrode comprises a layer of titanium formed on said current spreading layer and through said opening to contact an upper surface of said Mg+ doped window layer.

2. The light emitting diode in accordance with claim 1,

wherein said contact layer is a NiO_x/Au layer.

3. The light emitting diode in accordance with claim 1,

wherein said amorphous current spreading layer is formed of Indium Tin Oxide.

4. The light emitting diode diode in accordance with claim 2,

wherein said amorphous current spreading layer is formed of Indium Tin Oxide.

5. The light emitting diode in accordance with claim 1,

wherein said window structure comprises:

a Mg+ doped window layer; and

wherein said Ni/Au contact layer is formed on said Mg+ doped window layer and said first electrode forms an ohmic connection with said current spreading layer.

6. The light emitting diode in accordance with claim 5,

wherein said first electrode forms a Schottky diode connection with said Mg+ doped window layer.

7. The light emitting diode in accordance with claim 2,

wherein after heat treatment, said contact layer comprises a Ni oxide/Au layer.

8. A light emitting diode comprising:

a substrate;

a light emitting region;

a window structure; and

first and second electrodes;

wherein said window structure comprises;

an Mg+ doped window layer;

a semi-transparent NiO_x/Au contact layer formed on said Mg+ doped window layer; and

a semi-transparent, conductive amorphous current spreading layer formed of indium tin oxide directly on an exposed face of said contact layer;

wherein said first electrode forms an ohmic connection with said current spreading layer; and

forms a Schottky diode connection with said Mg+ doped window layer;

wherein an opening is formed through said contact layer and said current spreading layer; and

wherein said first electrode comprises a layer of titanium formed on said current spreading layer and through said opening to contact an upper surface of said Mg+ doped window layer.

9. A light emitting diode comprising:

a substrate;

a buffer region;

a GaN substitute substrate layer;

an n cladding layer;

an active region;

a p cladding layer;

a double window layer structure;

an n electrode;

a window structure comprising;

a semi-transparent metal contact layer, and

a semi-transparent, conductive amorphous current spreading layer formed directly on an exposed face of said contact layer;

a titanium electrode; and

a bond pad;

wherein an opening is formed through said contact layer and said current spreading layer to said double window layer structure for said titanium electrode.