High efficiency light emitting diode and method of making the same
AssigneeUnited Epitaxy Company, Ltd.
InventorTzer-Perng Chen
Life of this patent
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Abstract
A light emitting diode with high efficient reflective metal layer is disclosed. To prevent the reflective metal layer from reacting with the epi-LED layer structure during a thermal annealing process, a transparent electrical-conductive oxide layer such as ITO is formed in between them. Four preferred embodiments are proposed to improve the ohmic contact between the ITO layer and the epi-LED layers. There are: forming ohmic contact grid pattern, or ohmic contact channels in the ITO layer, or thin GaAs layer, or thin transparent metal layer at the interface between the ITO and the epi-LED layers.
Claims18
A light emitting diode comprising:
- a heat & electrical-conductive substrate;
- a light emitting epi-layers;
- a transparent electrical-conductive oxide layer formed on said light emitting epi-layers, said transparent electrical-conductive oxide layer having a plurality of ohmic contact channels formed and penetrated through said transparent electrical-conductive oxide layer;
- a reflective metal layer formed on said transparent electrical-conductive oxide layer;
- and
- a metal bonding layer bonded said heat & electrical-conductive substrate with said reflective metal layer.
The light emitting diode according to claim 5, further comprising a diffusion barrier layer formed in between said reflective metal layer and said metal bonding layer, further, said diffusion barrier layer is selected from the group consisting of electrical-conductive-oxide layer, refractory metal layer, and refractory metal silicide.
A light emitting diode comprising:
- a heat & electrical-conductive substrate;
- a light emitting epi-layers;
- a plurality of ohmic contact metal mesh or a grid pattern formed on said light emitting layers so as to uniformly distribute the injection current;
- a transparent electrical-conductive oxide layer formed on said light emitting epi-layers;
- a reflective metal layer formed on said transparent electrical-conductive oxide layer;
- and
- a metal bonding layer bonded said heat & electrical-conductive substrate with said reflective metal layer.
A light emitting diode comprising:
- a heat & electrical-conductive substrate;
- a light emitting epi-layers;
- a thin semiconductor layer or a transparent metal layer formed on said light emitting epi-layers, wherein said thin semiconductor layer is a highly doped III-V group compound layer with an energy bandgap smaller than that of an active layer of said light emitting epi-layers;
- a transparent electrical-conductive oxide layer formed on said thin semiconductor layer or said thin metal layer,
- a reflective metal layer formed on said transparent electrical-conductive oxide layer;
- and
- a metal bonding layer adhered said heat & electrical-conductive substrate with said reflective metal layer.
Dependencies are inferred from the claim text.