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US 2003/0164506 A1Published application
Light emitting devices with group III nitride contact layer and superlattice
AssigneeCree, Inc.
InventorsJohn Adam Edmond, Kathleen Marie Doverspike, Hua-Shuang Kong, Michael John Bergmann
Life of this patent
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Abstract
The present invention is a semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum. The semiconductor structure includes a first cladding layer of a Group III nitride, a second cladding layer of a Group III nitride, and an active layer of a Group III nitride that is positioned between the first and second cladding layers, and whose bandgap is smaller than the respective bandgaps of the first and second cladding layers. The semiconductor structure is characterized by the absence of gallium in one or more of these structural layers.
Claims25
A semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum, said structure comprising:
- a silicon carbide substrate;
- a first cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- a second cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- an active layer of AlxInyGa1−x−yN, where 0≦x<1 and 0≦y≦1 and 0≦(x+y)≦1, wherein said first cladding layer is positioned between said silicon carbide substrate and said active layer, and said active layer is positioned between said first cladding layer and said second cladding layer;
- a first ohmic contact, wherein said silicon carbide substrate is positioned between said first ohmic contact and said first cladding layer;
- a second ohmic contact, wherein said second cladding layer is positioned between said second ohmic contact and said active layer;
- and
- a Group III nitride contact layer, wherein said contact layer is positioned between said second ohmic contact and said second cladding layer, and said contact layer and said second cladding layer have the same conductivity type;
- wherein said first and second cladding layers have respective bandgaps that are each larger than the bandgap of said active layer;
- and
- wherein at least one of the layers selected from the group consisting of said first cladding layer, said second cladding layer, and said active layer is characterized by the absence of gallium.
8 more elements
A semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum, said structure comprising:
- a silicon carbide substrate;
- a first cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- a second cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- an active layer of AlxInyGa1−x−yN, where 0≦x<1 and 0≦y≦1 and 0≦(x+y)≦1, wherein said first cladding layer is positioned between said silicon carbide substrate and said active layer, and said active layer is positioned between said first cladding layer and said second cladding layer;
- a Group III nitride p-type superlattice contact layer, wherein said superlattice contact layer and said second cladding layer have the same conductivity type;
- a first ohmic contact, wherein said silicon carbide substrate is positioned between said first ohmic contact and said first cladding layer;
- and
- a second ohmic contact, wherein said superlattice contact layer is positioned between said second cladding layer and said second ohmic contact;
- wherein said first and second cladding layers have respective bandgaps that are each larger than the bandgap of said active layer;
- and
- wherein at least one of the layers selected from the group consisting of said first cladding layer, said second cladding layer, and said active layer is characterized by the absence of gallium.
8 more elements
A semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum, said structure comprising:
- a silicon carbide substrate;
- a first cladding layer consisting essentially of AlxIn1−xN, where 0<x≦1, and that is characterized by the absence of gallium;
- a second cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- and
- an active layer of AlxInyGa1−x−yN, where 0≦x<1 and 0≦y≦1 and (x+y)≦1, wherein said first cladding layer is positioned between said silicon carbide substrate and said active layer, and said active layer is positioned between said first cladding layer and said second cladding layer;
- a Group III nitride p-type superlattice contact layer formed from a plurality of Group III nitride layers selected from the group consisting of gallium nitride, indium nitride, AlxIn1−xN, where 0<x<1 , AlxGa1−xN, where 0<x<1, InxGa1−xN, where 0<x<1, and AlxInyGa1−x−yN, where 0<x<1 and 0<y<1 and (x+y)<1, wherein said superlattice contact layer and said second cladding layer have the same conductivity type;
- a first ohmic contact, wherein said silicon carbide substrate is positioned between said first ohmic contact and said first cladding layer;
- and
- a second ohmic contact, wherein said superlattice contact layer is positioned between said second cladding layer and said second ohmic contact;
- wherein said first and second cladding layers have respective bandgaps that are each larger than the bandgap of said active layer.
7 more elements
A semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum, said structure comprising:
- a silicon carbide substrate;
- a first cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- a second cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1;
- an active layer consisting essentially of AlxIn1−xN, where 0≦x<1, and that is characterized by the absence of gallium, wherein said first cladding layer is positioned between said silicon carbide substrate and said active layer, and said active layer is positioned between said first cladding layer and said second cladding layer;
- a Group III nitride p-type superlattice contact layer formed from a plurality of Group III nitride layers selected from the group consisting of gallium nitride, indium nitride, AlxIn1−xN, where 0<x<1, AlxGa1−xN, where 0<x<1, InxGa1−xN, where 0<x<1, and AlxInyGa1−x−yN, where 0<x<1 and 0<y<1 and (x+y)<1, wherein said superlattice contact layer and said second cladding layer have the same conductivity type;
- a first ohmic contact, wherein said silicon carbide substrate is positioned between said first ohmic contact and said first cladding layer;
- and
- a second ohmic contact, wherein said superlattice contact layer is positioned between said second cladding layer and said second ohmic contact;
- wherein said first and second cladding layers have respective bandgaps that are each larger than the bandgap of said active layer.
6 more elements
A semiconductor structure for light emitting devices that can emit in the red to ultraviolet portion of the electromagnetic spectrum, said structure, comprising:
- an active layer of AlxInyGa1−x−yN, where 0≦x<1 and 0≦y≦1 and 0≦(x+y)≦1, said active layer having a first surface and a second surface;
- a first cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1, said first cladding layer being in contact with said first surface of said active layer;
- a second cladding layer of AlxInyGa1−x−yN, where 0≦x≦1 and 0≦y<1 and (x+y)≦1, said second cladding layer being in contact with said second surface of said active layer, said first cladding layer and said second cladding layer having opposite conductivity types, each of said first and second cladding layers having a respective bandgap that is larger than the bandgap of said active layer;
- wherein at least one of the layers selected from the group consisting of said first cladding layer, said second cladding layer, and said active layer is characterized by the absence of gallium;
- a Group III nitride transition layer, said transition layer in contact with said first cladding layer and opposite said active layer, and having the same conductivity type as said first cladding layer;
- a conductive buffer layer in contact with said gallium nitride transition layer and opposite said first cladding layer, said conductive buffer layer being a Group III nitride selected from the group consisting of aluminum gallium nitride having the formula AlxGa1−xN, where 0≦x≦1, and aluminum indium nitride having the formula AlxIn1−xN, where 0≦x≦1;
- a single crystal silicon carbide substrate in contact with said conductive buffer layer and opposite said gallium nitride transition layer, said silicon carbide substrate having a polytype selected from the group consisting of 3C, 4H, 6H, and 15R, and said silicon carbide substrate and said first cladding layer having the same conductivity type;
- a first ohmic contact to said silicon carbide substrate and opposite said conductive buffer layer, said first ohmic contact comprising at least one metal selected from the group consisting of aluminum, nickel, titanium, gold, platinum, and vanadium, and layers, alloys, and blends thereof;
- a Group III nitride p-type superlattice contact layer on said second cladding layer and opposite said active layer, said contact layer and said second cladding layer having the same conductivity type, wherein said superlattice is formed from a plurality of Group III nitride layers selected from the group consisting of gallium nitride, indium nitride, AlxIn1−xN, where 0<x<1, AlxGa1−xN, where 0<x<1, InxGa1−xN, where 0<x<1, and AlxInyGa1−x−yN, where 0<x<1 and 0<y<1 and (x+y)<1;
- and
- a second ohmic contact to said Group III nitride contact layer and opposite said second cladding layer, said second ohmic contact comprising at least one metal selected from the group consisting of aluminum, nickel, titanium, gold, platinum, and vanadium, and layers, alloys, and blends thereof.
8 more elements
Dependencies are inferred from the claim text.