Optical devices featuring nonpolar textured semiconductor layers
First Claim
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1. A method for fabrication of a semiconductor structure, the method comprising:
- providing a substrate comprising a smooth surface having a predetermined material orientation, the substrate comprising a material selected from the group consisting of R-plane sapphire, A-plane silicon carbide, A-plane zinc oxide, A-plane gallium nitride, A-plane aluminum nitride and A-plane aluminum gallium nitride; and
depositing a first layer comprising a III-nitride material onto the smooth surface of the substrate, the first layer comprising an upper surface with a triangular texture as grown, wherein the faces of the triangles are the M-planes of the III-nitride material, and wherein the material comprises A-planes parallel to said predetermined material orientation.
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Abstract
A semiconductor emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate in a nonpolar orientation. The textured layers enhance light extraction, and the use of nonpolar orientation greatly enhances internal quantum efficiency compared to conventional devices. Both the internal and external quantum efficiencies of emitters of the invention can be 70-80% or higher. The invention provides highly efficient light emitting diodes suitable for solid state lighting.
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Citations
18 Claims
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1. A method for fabrication of a semiconductor structure, the method comprising:
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providing a substrate comprising a smooth surface having a predetermined material orientation, the substrate comprising a material selected from the group consisting of R-plane sapphire, A-plane silicon carbide, A-plane zinc oxide, A-plane gallium nitride, A-plane aluminum nitride and A-plane aluminum gallium nitride; and depositing a first layer comprising a III-nitride material onto the smooth surface of the substrate, the first layer comprising an upper surface with a triangular texture as grown, wherein the faces of the triangles are the M-planes of the III-nitride material, and wherein the material comprises A-planes parallel to said predetermined material orientation. - View Dependent Claims (2, 3, 4, 5)
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6. A method for fabrication of a semiconductor device, the method comprising:
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providing a substrate, the substrate comprising a material selected from the group consisting of R-plane sapphire, A-plane silicon carbide, A-plane zinc oxide, A-plane gallium nitride, A-plane aluminum nitride, and A-plane aluminum gallium nitride, wherein the substrate comprises a smooth surface having a predetermined material orientation; depositing a first layer comprising a III-nitride material onto the smooth surface of the substrate, the first layer comprising an upper surface with a triangular texture as grown, wherein the faces of the triangles are the M-planes of the III-nitride material, and wherein the material comprises A-planes parallel to said predetermined material orientation; depositing one or more quantum wells onto the first layer, the quantum wells comprising a III-nitride material and textured by the upper surface of the first layer; and depositing an upper layer onto the uppermost quantum well, the upper layer comprising a III-nitride material and textured by the uppermost quantum well, wherein deposition of the first layer and the upper layer includes depositing the layers with opposite p and n dopants to comprise a p-n junction therebetween. - View Dependent Claims (7, 8)
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9. A semiconductor device comprising:
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a substrate comprising a smooth surface having a predetermined material orientation, the substrate comprising a material selected from the group consisting of R-plane sapphire, A-plane silicon carbide, A-plane zinc oxide, A-plane gallium nitride, A-plane aluminum nitride, and A-plane aluminum gallium nitride; a first layer comprising a III-nitride material having an upper surface with a triangular texture as grown, wherein the faces of the triangles are the M-planes of the III-nitride material, and wherein the material comprises A-planes parallel to said predetermined material orientation; one or more quantum wells, each comprising a quantum well layer and a barrier layer, the quantum well layer and barrier layer each comprising a III-nitride material having a nonpolar plane oriented parallel to the M-plane of the first layer, and the one or more quantum wells overlaying the first layer; and an upper layer comprising a III-nitride material, the upper layer overlaying the one or more quantum wells and textured by the uppermost quantum well;
wherein the upper layer is grown on the uppermost quantum well layer, and the first layer and the upper layer have opposite p and n dopants to form a p-n junction between the first layer and the upper layer. - View Dependent Claims (10, 11, 12)
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13. A semiconductor structure comprising
a substrate comprising a smooth surface having a predetermined material orientation, the substrate comprising a material selected from the group consisting of R-plane sapphire, A-plane silicon carbide, A-plane zinc oxide, A-plane gallium nitride, A-plane aluminum nitride, and A-plane aluminum gallium nitride; -
a first layer comprising a III-nitride material having an upper surface with a triangular texture as grown, wherein the faces of the triangles are the M-planes of the III-nitride material, and wherein the material comprises A-planes parallel to said predetermined material orientation, the first layer overlaying the smooth surface of the substrate; and an upper layer comprising a III-nitride material, the upper layer overlaying the first layer and textured by the first layer;
wherein the upper layer is grown on the first layer, and the first layer and the upper layer have opposite p and n dopants to form a p-n junction between the first layer and the upper layer. - View Dependent Claims (14, 15)
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- 16. A template for the formation of a semiconductor device, the template comprising a nonpolar III-nitride material and formed as a layer having an upper surface and a lower surface, the upper surface having a textured as grown topology and having a nonpolar plane oriented parallel to the lower surface.
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