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US 6,495,862 B1Granted
Nitride semiconductor LED with embossed lead-out surface
AssigneeKabushiki Kaisha Toshiba
InventorsHaruhiko Okazaki, Koichi Nitta, Chiharu Nozaki
Life of this patent
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Abstract
Efficiency of leading out light released from an active layer, i.e. the external quantum efficiency, can be improved remarkably by processing a light lead-out surface to have an embossment. A layer containing a p-type dopant like magnesium (Mg) is deposited near the surface of a p-type GaN layer to diffuse it there, and a p-side electrode is made on the p-type GaN layer after removing the deposited layer. This results in ensuring ohmic contact with the p-side electrode, preventing exfoliation of the electrode and improving the reliability.
Claims13
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light lead-out surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a nitride compound semiconductor layer;
- and
- a transparent electrode;
- said embossment being formed on one surface of said nitride compound semiconductor layer, and said transparent electrode being formed on said one surface of said nitride compound semiconductor layer.
3 more elements
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light lead-out surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a nitride compound semiconductor layer;
- and
- a transparent electrode;
- said embossment being formed on one surface of said nitride compound semiconductor layer, and said transparent electrode being formed on said one surface of said nitride compound semiconductor layer;
- wherein said embossment includes a plurality of cylindrical lens-shaped convex portions.
4 more elements
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light lead-out surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a nitride compound semiconductor layer;
- and
- a transparent electrode;
- said embossment being formed on one surface of said nitride compound semiconductor layer, and said transparent electrode being formed on said one surface of said nitride compound semiconductor layer;
- wherein said embossment includes a hemispherical convex portion.
4 more elements
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light lead-out surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a nitride compound semiconductor layer;
- a transparent electrode;
- a nitride compound semiconductor layer having an even surface;
- and
- a transparent electrode formed on said nitride compound semiconductor layer;
- said embossment being formed on one surface of said nitride compound semiconductor layer, and said transparent electrode being formed on said one surface of said nitride compound s conductor layer and said embossment being formed on a surface of said transparent electrode.
5 more elements
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light readout surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a nitride compound semiconductor layer having an even surface;
- a transparent electrode formed on said even surface of said nitride compound semiconductor layer;
- and
- a light lead-out layer formed on said transparent electrode and having a transparency;
- said embossment being formed on a surface of said light lead-out layer.
4 more elements
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light lead-out surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a substrate made of a material other than nitride compound semiconductor;
- and
- a reflector reflecting a light emitted from said light emitting portion to release said light outside through said substrate;
- wherein said reflector also serves as an electrode injecting a current into said light emitting portion;
- and
- said light emitting portion being provided on one side of said substrate, and said embossment being provided on another side of said substrate.
5 more elements
A semiconductor light emitting device comprising:
- a light emitting portion made of a nitride compound semiconductor;
- a light lead-out surface on which an embossment is formed to improve the external quantum efficiency of light emitted from said light emitting portion;
- a substrate made of nitride compound semiconductor;
- and
- a reflector reflecting a light emitted from said light emitting portion to release said light outside through said substrate;
- wherein said reflector also serves as an electrode injecting a current into said light emitting portion;
- and
- said light emitting portion being provided on one side of said substrate, and said embossment being provided on another side of said substrate.
5 more elements
A semiconductor light emitting device comprising:
- a substrate;
- a mesa provided on one side of said substrate and including
- a light emitting portion;
- a reflector provided on said mesa and reflecting a light emitted from said light emitting portion to release said light outside through said substrate;
- a light-transmissive portion provided on a side surface of said mesa;
- a reflective layer coated on a surface of said light-transmissive portion;
- and
- an embossment provided on another side of said substrate
- to improve the external quantum efficiency of lights
- emitted from said light emitting portion,
- said reflective layer reflecting a light leaking sideward from said light emitting portion of said mesa so as to release the light outside through said substrate.
8 more elements
Dependencies are inferred from the claim text.