Light emitting diode and method of manufacturing the same

Abstract

A light emitting diode having high light extraction efficiency and a method of manufacturing the same are provided. The LED includes a semiconductor multiple layer including an active layer; a transparent electrode layer formed on the semiconductor multiple layer; and refraction field unit embedded in the transparent electrode layer and formed of a material having a different refractive index than the transparent electrode layer. The method of manufacturing the LED includes: crystallizing and growing a semiconductor multiple layer having an active layer on a substrate; evaporating a first transparent electrode layer onto the semiconductor multiple layer; forming a plurality of grooves in the first transparent electrode layer by patterning and etching the first transparent electrode layer; and evaporating a second transparent electrode layer onto the first transparent electrode layer at an angle to the grooves to form cavities filled with air between the first transparent electrode layer and the second transparent electrode layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present invention will be illustrated in detailed exemplary embodiments thereof with reference to the attached drawings in which:

FIG. 1 is a cross-sectional view of a conventional light emitting diode (LED);

FIG. 2 illustrates the optical path of light emitted in the LED of FIG. 1;

FIG. 3 is a cross-sectional view of an LED according to an embodiment of the present invention;

FIG. 4A is a schematic view illustrating the emission of light when the refractive index of refraction field unit is less than the refractive index of a transparent electrode layer in the LED of FIG. 3;

FIG. 4B is a schematic view illustrating the emission of light when the refractive index of refraction field unit is greater than the refractive index of a transparent electrode layer in the LED of FIG. 3;

FIG. 5 is a cross-sectional view of a comparative example LED for comparison with the LED of FIG. 3;

FIG. 6 is a schematic view illustrating the optical path of light in the LED of FIG. 5;

FIG. 7 is a graph of the increase rate of the light extraction efficiencies of the LEDs of FIGS. 3 and 5;

FIGS. 8A through 8D are cross-sectional views illustrating a method of manufacturing an LED according to an embodiment of the present invention; and

FIGS. 9A through 9C are cross-sectional views illustrating a method of manufacturing an LED according to another embodiment of the present invention.

Claims

1. A light emitting diode (LED) comprising: a semiconductor multiple layer comprising an active layer;a transparent electrode layer formed on the semiconductor multiple layer; anda refraction field unit embedded in the transparent electrode layer and formed of a material having a different refractive index than the transparent electrode layer.

2. The LED of claim 1, wherein the refraction field unit is formed of a material having a lower refractive index than the transparent electrode layer.

3. The LED of claim 2, wherein the transparent electrode layer is formed of a material selected from the group consisting of ITO, ZnO, and SnO2, and the refraction field unit is formed of a material selected from the group consisting of SiO2, porous SiO2, KDP, NH4H2PO4, CaCO3, BaB2O4, NaF, and Al2O3.

4. The LED of claim 1, wherein the refraction field unit is formed of a material having a higher refractive index than the transparent electrode layer.

5. The LED of claim 4, wherein the transparent electrode layer is formed of a material selected from the group consisting of ITO, ZnO, and SnO2, and the refraction field unit is formed of a material selected from the group consisting of SiC, LiNbO3, LilO3, PbMoO4, Nb2O5, TiO2, and ZrO2.

6. The LED of claim 1, wherein the refraction field unit comprises a plurality of cavities filled with air.

7. The LED of claim 1, wherein the refraction field unit comprises a plurality of refraction regions arranged at predetermined intervals in the transparent electrode layer.

8. The LED of claim 7, wherein the interval of the refraction regions is at least 0.5 times the wavelength of light generated by the active layer.

9. A method of manufacturing an LED comprising: forming a semiconductor multiple layer having an active layer on a substrate;evaporating a first transparent electrode layer onto the semiconductor multiple layer;forming a refraction layer on the first transparent electrode layer by evaporating a material having a different refractive index than the first transparent electrode layer onto the first transparent electrode layer;forming refraction field unit by patterning and etching the refraction layer; andembedding the refraction field unit by evaporating a second transparent electrode layer on the refraction field unit and the first transparent electrode layer.

10. The LED of claim 9, wherein the refraction field unit comprises a plurality of refraction regions arranged at predetermined intervals in the transparent electrode layer.

11. The LED of claim 10, wherein the interval of the refraction regions is at least 0.5 times the wavelength of light generated by the active layer.

12. A method of manufacturing the LED of claim 6, the method comprising: forming a semiconductor multiple layer having an active layer on a substrate;evaporating a first transparent electrode layer onto the semiconductor multiple layer;forming a plurality of grooves in the first transparent electrode layer by patterning and etching the first transparent electrode layer; andevaporating a second transparent electrode layer onto the first transparent electrode layer at an angle to the grooves to form refraction field unit formed of cavities filled with air between the first transparent electrode layer and the second transparent electrode layer.