US 7,442,962 B2 · High-brightness gallium-nitride based light emitting diode structure

Abstract

A GaN-based LED structure is provided so that the brightness and lighting efficiency of the GaN-based LED are enhanced effectively. The greatest difference between the GaN-based LEDs according to the invention and the prior arts lies in the addition of a thin layer on top of the traditional structure. The thin layer could be formed using silicon-nitride (SiN), or it could have a superlattice structure either made of layers of SiN and undoped indium-gallium-nitride (InGaN), or made of layers SiN and undoped aluminum-gallium-indium-nitride (AlGaInN), respectively. Because of the use of SiN in the thin layer, the surfaces of the GaN-based LEDs would be micro-roughened, and the total internal reflection resulted from the GaN-based LEDs' higher index of refraction than the atmosphere could be avoided.

Claims24

Dependent claims

A GaN-based LED structure, comprising:

a substrate;
a first contact layer made of a GaN-based material having a first conduction type located on top of said substrate;
an active layer made of a GaN-based material located on top of said first contact layer;
a second contact layer made of a GaN-based material having a second conduction type opposite to said first conduction type located on top of said active layer;
and
a micro-roughened thin layer made of at least a SiN-based material located on top of said second contact layer;
wherein said micro-roughed thin layer contains multiple un-uniformly distributed micro-clusters of said SiN-based material for improving external quantum efficiency by reducing total internal reflection of light inside said GaN-based LED structure.

4 more elements

A GaN-based LED device, comprising:

a substrate;
a buffer layer made of AlaGabIn1-a-bN (0≦a,b<1, a+b≦1) having a specific composition located on top of an upper side of said substrate;
a first contact layer made of a GaN-based material having a first conduction type located on top of said buffer layer;
an active layer made of InGaN located on top of a part of said first contact layer's upper surface;
a first electrode located on top of another part of said first contact layer's upper surface not covered by said active layer;
a second contact layer made of a GaN-based material having a second conduction type opposite to said first conduction type located on top of said active layer;
a micro-roughened thin layer made of at least a SiN-based material located on top of said second contact layer;
a transparent conductive layer that is one of a metallic conductive layer and a transparent oxide layer located on top of said micro-roughened thin layer's upper surface;
and
a second electrode located on top of said transparent conductive layer or on top of another part of said micro-roughened thin layer's upper surface not covered by said transparent conductive layer;
wherein said micro-roughed thin layer contains multiple un-uniformly distributed micro-clusters of said SiN-based material for improving external quantum efficiency by reducing total internal reflection of light inside said GaN-based LED structure.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application

11/266,462Filed 3 Nov 2005 · continuation in part

Priority

12 Nov 2004

Published

US 2006/0102921 A118 May 2006

Granted

28 Oct 2008

Term ends

Not estimatedThe source records don’t support an estimate.

Classification5 codes

H10H 20/816
Bodies: having carrier transport control structures, e.g. highly-doped semiconductor layers or current-blocking structures
H10H 20/82
Characterised by their shape, e.g. curved or truncated substrates: roughened surfaces, e.g. at the interface between epitaxial layers
H10H 20/811
Bodies: having quantum effect structures or superlattices, e.g. tunnel junctions
H10H 20/825
Comprising only Group III-V materials, e.g. GaP: containing nitrogen, e.g. GaN

Family

Application10/987,518Parent of this continuation-in-part · filed 12 Nov 2004

US 2006/0102921 A1Pre-grant publication · published 18 May 2006

US 7,180,097 B2Parent of this continuation-in-part · filed 20 Feb 2007

US 2006/0102930 A1Published application

US 7,442,962 B2This patent

From the US filing history. Foreign family members aren’t listed.

High-brightness gallium-nitride based light emitting diode structure

Life of this patent

High-brightness gallium-nitride based light emitting diode structure

Life of this patent

Abstract

Claims24