KR101233234B1 - Light emitting diode filled metal colloid in embedded electrode and fabrication method thereof - Google Patents

Abstract

PURPOSE: A light emitting diode with metal colloid filled in an embedded electrode and a manufacturing method thereof are provided to enhance light extraction efficiency by improving a current spreading property in an n-layer. CONSTITUTION: A buffer layer(5) is formed on a substrate. An n-layer(6) is formed on the buffer layer. An n-electrode is formed on the n-layer. An embedded electrode is formed on the buffer layer and the n-layer across the substrate. Metal island is formed on one end or both ends of the embedded electrode.

Description

Light emitting diode filled metal colloid in embedded electrode and fabrication method

The present invention relates to a light emitting diode and a method of manufacturing the same, and more particularly, to form a space for one or more intrinsic electrodes across the buffer layer and the n-layer across the substrate and filling the metal colloid therein to n-layer current The present invention relates to a light emitting diode in which a metal colloid is filled in an internal electrode for improving diffusion characteristics and improving light extraction efficiency of a light emitting diode, and a method of manufacturing the same.

FIG. 11 is a cross-sectional view illustrating a structure of a light emitting diode using a nitride semiconductor according to the related art, and has a structure of a current injection type light emitting diode in which all electrodes are formed on an upper surface thereof.

The light emitting diode has a structure in which electrons and holes generated by the n-electrode 26 and the p-electrode 27 are diffused into the active layer 23, in which current flows from the p-electrode 27 to the n-electrode 26. Since it mainly flows along the side of the mesa structure, which is the shortest distance to the electron, holes and electrons are not evenly diffused in the active layer 23, the luminous efficiency is low. Methods of activating and activating current diffusion in the n-layer 23 have been attempted.

In addition, the light emitting diode and its manufacturing method including the current diffusion layer of Korean Patent Publication No. 10-0700529 form a high conductivity material inside the n-contact layer to improve side current diffusion characteristics of the n-contact layer. By improving the side current spreading characteristics, the high conductivity material may also serve to enhance light efficiency such as focusing or transmitting light in a specific direction.

However, this has a problem that current injection from the n-electrode to each individual pattern cannot be made evenly by the current diffusion pattern formed therein. In addition, there is a disadvantage in that an additional mask is required to make the current diffusion pattern.

Republic of Korea Patent Registration No. 10-0700529 (2007.03.21)

SUMMARY OF THE INVENTION An object of the present invention is to form a space for one or more intrinsic electrodes formed over a buffer layer and an n-layer across a substrate and fill metal colloids therein to improve the n-layer current diffusion characteristics in order to solve the above problems. The present invention provides a light emitting diode and a method of manufacturing the same, which improve the light extraction efficiency of the light emitting diode.

In order to achieve the above object, the present invention provides a substrate, a buffer layer formed on the substrate, an n-layer formed on the buffer layer, an n-electrode formed on the n-layer, and a buffer layer and n layers across the substrate. Provided is a light emitting diode including an intrinsic electrode filled with a metal, one or both ends of the intrinsic electrode, and at least one metal island and an extension electrode connecting the at least one metal island and the n-electrode.

In order to achieve the above object, the present invention provides a method for preparing a substrate, forming a silicon oxide layer on the substrate, etching the silicon oxide layer to cross the substrate, and at least one metal island connected to the embedded electrode. Forming a pattern for the substrate, forming a buffer layer on the substrate, forming an n-layer, an active layer, and a p-layer on the buffer layer, etching the silicon oxide forming the pattern for the intrinsic electrode and the pattern for the metal island, forming an n-electrode and a p-electrode including respective extension electrodes on the n-layer and p-layer, forming a PR pattern exposing holes (holes) formed by etching an oxide pattern for metal islands, The light emitting die includes filling a metal colloid with a space in which the pattern for the metal island and the pattern for the intrinsic electrode are etched, and removing and heat treating the PR pattern. It provides a method for producing de.

According to the present invention, an intrinsic electrode is formed in a light emitting diode and a metal colloid is filled therein to improve n-layer horizontal current spreading characteristics and to improve light extraction efficiency of the light emitting diode (high light extraction efficiency). ) Is effective.

1 is a cross-sectional view of a light emitting diode which is an embodiment of the present invention;
2 is a perspective view of a light emitting diode which is an embodiment of the present invention;
3 is a flowchart of a light emitting diode according to an embodiment of the present invention;
4 is a schematic diagram of filling a metal colloid into a light emitting diode;
FIG. 5 is a SEM photograph in which only a portion without a PR pattern is filled with a metal colloid by a PR pattern formed on a hole (hole) formed by etching an oxide pattern after growth;
6 is a SEM photograph before and after the Ag colloid is filled with a space in which the pattern for the intrinsic electrode of the light emitting diode according to the embodiment of the present invention is etched,
Figure 7 is an optical micrograph before (a), after filling (b) and after heat treatment (c) of the Ag colloid filled in the pattern for the etched intrinsic electrode of the light emitting diode of an embodiment of the present invention,
8 is a graph of reflectivity of Ag thin film and Ag colloid,
9 is a process flow chart using the air-bar,
10 is a process flowchart using a thick silicon oxide pattern,
11 is a cross-sectional view of a conventional light emitting diode.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. These examples are provided to illustrate the scope of the invention to those skilled in the art with respect to the present invention. Therefore, the present invention is not limited to the following embodiments, but may be implemented in various forms within the scope of the claims of the present invention. In addition, the thickness or size of each component in the drawings are exaggerated for convenience and clarity of description, and in adding reference numerals to the components of each drawing, even if the same components are shown in different drawings The same reference numerals are used as much as possible, and detailed descriptions of functions and configurations which are not the gist of the present invention are omitted.

1 and 2, a light emitting diode according to an embodiment of the present invention includes a substrate 1, a buffer layer 5 formed on the substrate 1, an n-layer 6 formed on the buffer layer 5, an n-electrode 10 formed on the n-layer 6, one or more internal electrodes 14 formed over the buffer layer 5 and the n-layer 6 across the substrate 1, and an internal electrode ( 14 and one or more metal islands 15 formed at one end or both ends thereof, and an extension electrode 9 connecting the one or more metal islands 15 and the n-electrode 10.

In addition, the light emitting diode according to the embodiment of the present invention may be filled with the metal colloid 13 (see FIG. 4) in the internal electrode 14.

Referring to the manufacturing method of the light emitting diode according to the embodiment of the present invention having such a configuration as follows.

A manufacturing process as an embodiment of the present invention comprises the steps of preparing the substrate 1, forming the silicon oxide layer 2 on the substrate 1, etching the silicon oxide layer 2 to cross the substrate 1 Forming an embedded electrode pattern (3) and at least one metal island pattern (4) connected to the embedded electrode, forming a buffer layer (5) on the substrate (1), and forming an n-layer on the buffer layer (5) 6), forming the active layer (7), p-layer (8), etching the silicon oxide layer (2) forming the pattern for the intrinsic electrode (3) and the pattern for the metal island (4), n-layer Forming an n-electrode 10 and a p-electrode 11 including respective extension electrodes 9 on the p-layer 8 and the holes formed over the oxide pattern 4 for metal islands. Forming a PR pattern 12 exposing the (holes), filling the Ag colloid 13 with a space in which the metal island pattern 4 and the intrinsic electrode pattern 3 are etched, and the PR pattern 12 ) And heat treatment.

First, as shown in FIG. 3A, the substrate 1 is prepared. Substrate 1 includes a sapphire (Al ₂ O ₃ ) substrate, a silicon (Si) substrate, a silicon carbide (SiC) substrate, a zinc oxide (ZnO) substrate, a gallium arsenide (GaAs) substrate and a gallium phosphide (GaP) substrate, LiAlO ₂ Any one of a substrate and a LiGaO ₂ substrate may be used, and an sapphire substrate is used in the embodiment of the present invention.

Thereafter, as shown in FIG. 3B, an oxide layer 2 is formed on the substrate 1. The oxide layer 2 is an oxide-based (e.g. XOy or X ₂ Oy form, X is Ba, Be, Ce, Cr, Er, Ga, In, Mg, Ni, Si, Sc, Ta, Ti, Zn, Zr Any one of and Y is 0 <y ≤ 9) may be formed by depositing a plasma CVD (Chemical Vapor Deposition) method, E-Beam or sputtering method. In an embodiment of the present invention, a silicon oxide (SiO ₂ ) layer 2 is stacked.

Thereafter, as shown in FIG. 3C, the PR pattern 30 is formed.

Next, the silicon oxide layer 2 is etched to form a pattern 3 for the intrinsic electrode crossing the substrate 1 and at least one metal island pattern 4 connected to the intrinsic electrode (see FIG. 3). (d)).

Then, the buffer layer 5 is formed on the substrate 1, and the n-layer 6, the active layer 7, and the p-layer 8 are laminated on the buffer layer 5 (see FIG. 3E). ).

Thereafter, as illustrated in FIG. 3F, the silicon oxide layer 2 forming the intrinsic electrode pattern 3 and the metal island pattern 4 is etched. In this case, the space in which the pattern for the embedded electrode is etched may be formed as shown in FIG. 9 or FIG. 10.

FIG. 9 is a process flowchart using an air-bar, and FIG. 10 is a process flowchart using a thick silicon oxide pattern.

The prisms of FIG. 9 may be formed by first etching the pattern for the intrinsic electrode 3 and then etching the semiconductor layer by applying a KOH solution to a space where the pattern for the intrinsic electrode 3 is etched. On the contrary, FIG. 10 shows that the internal electrode pattern is formed to be thick, so that when the internal electrode pattern is etched, a space sufficient for the characteristics of the internal electrode can be secured without etching additional semiconductor layers.

Next, an n-electrode 10 and a p-electrode 11 including respective extension electrodes 9 are formed on the n-layer 6 and the p-layer 8 (FIG. 3G). Reference).

Then, the PR pattern 12 exposing the holes (holes) formed by etching the oxide pattern 4 for metal islands is formed (see (h) of FIG. 3 and SEM image of FIG. 5).

Thereafter, as shown in FIG. 3 (i), the metal colloid 13 is filled with a space in which the metal island pattern 4 and the internal electrode pattern 3 are etched. Metal colloids are materials that make ohmic contacts with n-type semiconductors and include Ag, Al, Au, B, Be, Bi, C, Cr, Co, Cu, Fe, In, Ir, Mg, Mo, Nb, Ni, Pb, Any one or more of Pd, Si, Sn, Ti, W, Zn, and can be formed by spray method, gas evaporation, pulsed laser deposition, solvothermal synthesis, Penchini method, co-precipitation method. In this embodiment, Ag colloid is used. (See FIG. 3 (j) and FIG. 6 SEM photograph.)

Referring to the drawing shown in Figure 4, the method of filling the Ag colloid (colloid) is first soaked the light emitting diode in Ag colloid 4% solution (Ag colloid 4% / water) mixed with water (water), and then ultrasonic (ultrasonic) Shake for 5 minutes, or spin coating at 2000 rpm / 20s, or both. Thereafter, the PR pattern 15 is taken out and lifted off, followed by annealing in air at 600 ° C./2 min.

Figure 8 shows the difference in reflectance by Ag thin film and Ag colloid. At a wavelength of about 460 nm, Ag colloid shows about 70% reflectivity. Rather than applying an additional thin film growth process (E-BEAM, Thermal evaporation, etc.), it is a simpler process than the 82% reflectivity of Ag thin film by an additional thin film growth process. In addition to the effect, a further increase in light extraction efficiency due to reflectance can be realized.

The present invention is not limited to the above-described embodiments, and any person having ordinary skill in the art to which the present invention pertains may make various modifications without departing from the gist of the present invention as claimed in the claims. Such changes will fall within the scope of the claims.

1: substrate;
5: buffer layer
6: n-layer
9: extended electrode
10: n-electrode
14: embedded electrode
15: Metal Island

Claims (8)

Board;
A buffer layer formed on the substrate;
An n-layer formed on the buffer layer;
An n-electrode formed on the n-layer;
An intrinsic electrode formed over the buffer layer and the n-layer across the substrate and filled with a metal;
At least one metal island formed at one or both ends of the intrinsic electrode;
And at least one expansion electrode connecting the at least one metal island and the n-electrode. The method of claim 1,
Light-emitting diode, characterized in that the metal is filled in the form of a colloid. The method of claim 1,
The metal filled in the intrinsic electrode may be Ag, Al, Au, B, Be, Bi, C, Cr, Cu, Fe, In, Ir, Mg, Mo, Ni, or Pb as a material for ohmic contact with an n-type semiconductor. Light emitting diode, characterized in that using any one or two or more of Si, Sn, Ti, W, Zn. The method of claim 1,
Light emitting diodes, characterized in that the cross-section of the embedded electrode is a triangle. The method of claim 1,
Light emitting diodes, characterized in that the cross section of the intrinsic electrode is a rectangle. Preparing a substrate;
Forming a silicon oxide layer on the substrate;
Etching the silicon oxide layer to form a pattern for the intrinsic electrode crossing the substrate and at least one metal island pattern connected to the intrinsic electrode;
Forming a buffer layer on the substrate;
Forming an n-layer, an active layer, and a p-layer in the buffer layer;
Etching silicon oxide forming the intrinsic electrode pattern and the metal island pattern;
Forming an n-electrode and a p-electrode including respective extension electrodes on the n- and p-layers;
Forming a PR pattern exposing the hole (hole) formed by etching the oxide pattern for metal islands;
Filling the metal colloid with a space in which the pattern for the metal island and the pattern for the internal electrode are etched; And
Removing the PR pattern and performing a heat treatment. The method according to claim 6,
In the step of filling the metal colloid, the method of manufacturing a light emitting diode, characterized in that the use of ultrasonic waves. The method according to claim 6,
In the filling of the metal colloid, a method of manufacturing a light emitting diode, characterized in that using spin coating.

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