US 6,608,328 B2 · Semiconductor light emitting diode on a misoriented substrate

Abstract

A light emitting diode is made by a compound semiconductor in which light is emitted from an active region with a multiple quantum well structure. The active region is sandwiched by InGaAlP-based lower and upper cladding layers. Emission efficiency of the active region is improved by adding light and electron reflectors in the light emitting diode. These InGaAlP-based layers are grown epitaxially by Organometallic Vapor-Phase Epitaxy (OMVPE) on a GaAs substrate with a misorientation angle toward <111>A to improve the quality and surface morphology of the epilayer and performance in light emitting. The lower cladding layer of first conductivity type forms on a misoriented substrate with the same type of conductivity. Light transparent and current diffusion layers with a second conductivity is formed on top of the upper cladding layer for the spreading of current and expansion of the emission light. These light transparent layers include a barrier layer, a lattice gradient layer, and a window layer with band gaps transparent to the emitting light.

Claims28

Dependent claims

A light emitting diode comprising:

a bottom electrode contact;
a GaAs substrate of first conductivity on said bottom electrode contact;
a GaAs buffer layer on said GaAs substrate;
a first InGaAlP layer on said GaAs buffer layer;
an active layer on said first InGaAlP layer;
a second InGaAlP layer of second conductivity opposite to said first conductivity on said active layer;
a light extraction layer on said second InGaAlP layer, wherein said light extraction layer blocks and spreads currents from said second InGaAlP layer, and said light extraction layer comprises a current blocking layer on said second InGaAlP layer, wherein said current blocking layer comprises a In0.5(Ga1−xAlx)0.5P layer of said second conductivity and thickness of said current blocking layer is about 10-100 nm;
a lattice gradient layer on said current blocking layer to accommodate the difference in lattice constant between said current blocking layer and subsequent layer;
and a window layer on said lattice gradient layer for the current spreading in said light emitting diode;
and
a top electrode contact layer on said light extraction layer.

8 more elements

Dependencies are inferred from the claim text.

Semiconductor light emitting diode on a misoriented substrate

Life of this patent

Semiconductor light emitting diode on a misoriented substrate

Life of this patent

Abstract

Claims28