KR101165255B1 - High efficiency light emitting diode and method of fabricating the same - Google Patents

Abstract

A high efficiency light emitting diode and a method of manufacturing the same are disclosed. This light emitting diode includes: a substrate; A first light emitting cell and a second light emitting cell each including a first conductive upper semiconductor layer, an active layer, and a second conductive lower semiconductor layer; An intermediate insulating layer disposed between the first and second light emitting cells and the substrate to insulate the first and second light emitting cells from the substrate, and a distributed Bragg reflector repeatedly stacked with an insulating layer having a different refractive index; A transparent ohmic contact layer disposed between the intermediate insulating layer and each light emitting cell and in contact with the second conductive lower semiconductor layer of each of the first and second light emitting cells; And a connection part electrically connecting the first conductive upper semiconductor layer of the first light emitting cell to the transparent ohmic contact layer contacting the second conductive lower semiconductor layer of the second light emitting cell.

Description

High-Efficiency Light-Emitting Diodes and Methods of Manufacturing Them {High EFFICIENCY LIGHT EMITTING DIODE AND METHOD OF FABRICATING THE SAME

The present invention relates to a light emitting diode and a method of manufacturing the same, and more particularly, to a high efficiency light emitting diode and a method of manufacturing the same by applying a substrate separation process.

A light emitting diode is a semiconductor device having an N-type semiconductor and a P-type semiconductor, and emits light by recombination of electrons and holes. Such light emitting diodes are widely used as display devices and backlights. In addition, the light emitting diode consumes less power and has a longer lifespan than existing light bulbs or fluorescent lamps, thereby replacing its incandescent lamps and fluorescent lamps, thereby expanding its use area for general lighting.

Recently, AC light emitting diodes that emit light continuously by directly connecting the light emitting diodes to AC power have been commercialized. Light emitting diodes that can be used directly in connection with high voltage alternating current power supplies are described, for example, in Published International Publication No. WO 2004/023568 (Al), which are referred to as "light-emitting elements having light-emitting components". The title is disclosed by SAKAI et al.

According to WO 2004/023568 (Al), series LED arrays are formed two-dimensionally connected on an insulating substrate, such as a sapphire substrate. LED arrays in series can provide a light emitting diode that can be driven at a high voltage. In addition, such LED arrays are connected in anti-parallel on the sapphire substrate to provide a single chip light emitting device that can be driven by an AC power supply.

Since the AC-LED forms light emitting cells on a substrate used as a growth substrate, for example, a sapphire substrate, there is a limitation in the structure of the light emitting cells and there is a limit in improving light extraction efficiency. In order to solve this problem, a method of manufacturing a light emitting diode, such as an AC-LED, having light emitting cells connected in series by applying a substrate separation process, has been studied.

1 is a cross-sectional view illustrating a light emitting diode having light emitting cells connected in series according to the prior art.

Referring to FIG. 1, the light emitting diode includes a substrate 51, a bonding metal 41, an adhesive layer 39, an intermediate insulating layer 37, a barrier metal layer 35, a reflective metal layer 33, and a plurality of light emitting cells ( Only two, S1 and S2, insulating layer 53 and connecting portion 55 are included.

The substrate 51 is distinguished from a growth substrate (not shown), and is a secondary substrate bonded through the bonding metal 41 after growing the nitride semiconductor layers 25, 27, and 29 on the growth substrate.

Meanwhile, the light emitting cells S1 and S2 include an n-type nitride semiconductor layer 25, an active layer 27, and a p-type nitride semiconductor layer 29, and are roughened on the top surface of the n-type nitride semiconductor layer 25. Surface R may be formed.

An intermediate insulating layer 37 is interposed between the substrate 51 and the light emitting cells S1 and S2 to electrically insulate the light emitting cells S1 and S2 from the substrate 51. In addition, a reflective metal layer 33 and a barrier metal layer 35 are interposed between the intermediate insulating layer 37 and the light emitting cells S1 and S2. The reflective metal layer 33 improves light emission efficiency by reflecting light generated in the light emitting cells S1 and S2 toward the substrate 51. The barrier metal layer 35 covers the reflective metal layer 33 to prevent diffusion of the reflective metal layer 33 and prevents the reflective metal layer 33 from being oxidized. Furthermore, a part of the barrier metal layer 35 extends from the region under the light emitting cell S2 to the cell isolation region and is exposed.

The connection part 55 connects the n-type semiconductor layer 25 of the light emitting cell S1 and the barrier metal layer 35 to connect the light emitting cells S1 and S2 in series. In addition, the insulating layer 53 is interposed between the light emitting cells S1 and S2 and the connecting portion 55 such that the n-type semiconductor layer 25 and the p-type semiconductor layer 29 are electrically shorted by the connecting portion 55. Prevent it.

Silver (Ag) is generally used as the reflective metal layer 33. Ag is very strong in oxidizing power and easily diffuses by heat. Furthermore, the etching gas used to separate the light emitting cells S1 and S2, for example, BCl3 / Cl2 gas, chemically reacts with Ag to easily produce an by-product. It may stick to the sides of S1, S2) and cause an electrical short. In order to prevent this, the related art covers the reflective metal layer 33 with the barrier metal layer 35 and exposes the barrier metal layer 35 in the light emitting cells S1 and S2 separation process.

However, according to the prior art, since the barrier metal layer 35 has to be added to protect the reflective metal layer 33, the metal layer deposition process is complicated. Furthermore, since the barrier metal layer 35 covers the reflective metal layer 33 after the reflective metal layer 33 is formed, a step occurs in the side of the reflective metal layer 33. This step becomes larger as the thickness of the reflective metal layer 33 increases. In particular, in the case where the barrier metal layer 35 is formed by depositing a plurality of metal layers, it is highly likely that stress is concentrated in the stepped portion, causing cracking of the barrier metal layer 35. In particular, since the substrate 51 is bonded at a relatively high temperature, cracks may occur in the stepped portion during bonding of the substrate 51, thereby causing device defects.

On the other hand, by forming the reflective metal layer 33 with Ag, the reflectance can be relatively increased compared to other metal layers, but a new technology for adopting a more stable reflecting layer and further increasing the reflectance compared to Ag is required.

Patent Document 1: International Publication No. WO 2004/023568 (Al)

An object of the present invention is to provide a high-efficiency light emitting diode and a method of manufacturing the same that can prevent an electrical short circuit in the light emitting cell due to metal etching by-products.

Another object of the present invention is to provide a light emitting diode having a further improved reflectance and a method of manufacturing the same.

Another object of the present invention is to provide a method of manufacturing a light emitting diode that can simplify the process and improve reliability.

A light emitting diode according to an aspect of the present invention, the substrate; A first light emitting cell and a second light emitting cell each including a first conductive upper semiconductor layer, an active layer, and a second conductive lower semiconductor layer; An intermediate insulating layer disposed between the first and second light emitting cells and the substrate to insulate the first and second light emitting cells from the substrate, and a distributed Bragg reflector repeatedly stacked with an insulating layer having a different refractive index; A transparent ohmic contact layer disposed between the intermediate insulating layer and each of the light emitting cells and contacting a second conductive lower semiconductor layer of each of the first and second light emitting cells; And a connector electrically connecting the first conductive upper semiconductor layer of the first light emitting cell to the transparent ohmic contact layer contacting the second conductive lower semiconductor layer of the second light emitting cell.

The intermediate insulating layer may be formed of, for example, a multilayer film obtained by repeatedly stacking SiO ₂ / TiO ₂ or SiO ₂ / Nb ₂ O ₅ , and since the adhesion of SiO ₂ is generally excellent, the first and second light emitting cells It is preferable that the first layer of the first insulating reflective layer and the first layer of the second insulating reflective layer close to these sides be SiO ₂ .

On the other hand, the intermediate insulating layer may exhibit a reflectance of 95% or more, preferably 99% or more with respect to the wavelengths of the blue light, green light, and red light regions.

The transparent ohmic contact layer may be an indium tin oxide layer (ITO) or a zinc oxide layer (ZnO).

In some embodiments, a reflective metal layer may be interposed between the intermediate insulating layer and the substrate. The reflective metal layer may be, for example, Al, and further reflects light passing through the DBR to further improve the reflectance.

The light emitting diode has a cell isolation region between the first light emitting cell and the second light emitting cell, and the transparent ohmic contact layer contacting the second conductive lower semiconductor layer of the second light emitting cell is the cell isolation region. Is extended.

In this case, one end of the connection part contacts the first conductive upper semiconductor layer of the first light emitting cell, the connection part extends along the side surface of the first light emitting cell from the one end, and the other end of the connection part is The transparent ohmic contact layer may contact the cell isolation region.

The light emitting diode may further include a first insulating layer interposed between the connecting portion and the side surface of the first light emitting cell to insulate the connecting portion from the side surface of the first light emitting cell. Furthermore, the light emitting diode may further include a second insulating layer covering the connection part together with the first light emitting cell and the second light emitting cell.

In addition, the first conductive upper semiconductor layer of the first and second light emitting cells may have a roughened surface, and the second insulating layer may cover the roughened surface of the first conductive upper semiconductor layer. In this case, the surface of the second insulating layer may have an uneven shape along the roughened surface of the first conductive upper semiconductor layer. Accordingly, the light extraction efficiency through the roughened surface is further improved.

According to another aspect of the present invention, a method of manufacturing a light emitting diode is provided. The method includes growing a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on a growth substrate, forming transparent ohmic contact layers spaced apart from each other on the second conductive semiconductor layer, and forming the transparent ohmic. Repeatedly stacking insulating layers having different refractive indices on the contact layers to form an intermediate insulating layer of a distributed Bragg reflector covering the transparent ohmic contact layers, bonding a secondary substrate on the intermediate insulating layer, and forming the growth substrate. Removing and exposing the first conductive semiconductor layer, and etching the first conductive semiconductor layer, the active layer and the second conductive semiconductor layer to form a cell isolation region to define a first light emitting cell and a second light emitting cell, A transparent ohmic contact layer below the second light emitting cell is exposed in the cell isolation region, and a first insulating layer covering at least part of side surfaces of the first light emitting cell and the second light emitting cell is formed, and the first light emission is performed. And of the includes forming a first connection portion that electrically connect the conductive semiconductor layer and the second light emitting cells of the lower transparent ohmic contact layer.

Meanwhile, before bonding the secondary substrate, a reflective metal layer may be formed on the intermediate insulating layer. In addition, a roughened surface may be formed on the exposed first conductive semiconductor layer.

Furthermore, the method may further include forming a second insulating layer covering the connection part together with the first and second light emitting cells. In this case, the second insulating layer may be formed along the roughened surface of the first conductivity-type semiconductor layer to have an uneven shape.

According to the present invention, by forming a reflective layer using a distributed Bragg reflector, the light extraction efficiency is improved by having a higher reflectance with respect to the light generated in the active layer compared with the conventional metal reflective layer. Furthermore, since the ohmic contact is formed using the transparent ohmic contact layer, there is no need to separately form a barrier metal layer for protecting the transparent ohmic contact layer, thereby simplifying the process and further providing a highly reliable light emitting diode. have. Moreover, by employing a transparent ohmic contact layer, it is possible to suppress the generation of etching by-products that cause an electrical short during the etching process.

In addition, the intermediate insulating layer may be formed of a distributed Bragg reflector having a high reflectance in a wide visible region of blue light, green light, and red light, and in this case, exhibits high reflectance even for light entering the light emitting diode from the outside. Therefore, high light efficiency may be exhibited in a light emitting diode package that implements multicolor light, for example, white light.

1 is a cross-sectional view illustrating a light emitting diode having light emitting cells connected in series according to the prior art.
2 is a schematic plan view illustrating a light emitting diode according to an embodiment of the present invention.
3 is a cross-sectional view taken along the line AA in FIG. 2.
4 to 9 are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention can be fully conveyed to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, and the like of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

FIG. 2 is a schematic plan view illustrating a light emitting diode according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line A-A of FIG. 2.

2 and 3, the light emitting diode includes a substrate 151, first and second light emitting cells S1 and S2, an intermediate insulating layer 137, transparent ohmic contact layers 135, and a connector 155. ). In addition, the light emitting diode may include a reflective metal layer 138, an adhesive layer 139, and a bonding metal 141, and may also include a first insulating layer 153 and a second insulating layer 157. .

The substrate 151 is separated from a growth substrate for growing the compound semiconductor layers and is a substrate attached to the compound semiconductor layers that have already been grown. The substrate 151 may be variously selected according to the purpose of use, and in particular, the substrate 151 may be a substrate having a high thermal conductivity, for example, Si, SiC, AlN, or a metal material to improve heat dissipation characteristics. However, the substrate is not particularly limited and may be another kind of insulating or conductive substrate. In particular, when using a sapphire substrate as the growth substrate of the semiconductor layers, the substrate 151 may be a sapphire substrate to have the same thermal expansion coefficient as the growth substrate.

The light emitting cells S1 and S2 are separated by a cell isolation region 130a. Each of the light emitting cells S1 and S2 includes a semiconductor stack 130 including an upper semiconductor layer 125 of a first conductivity type, an active layer 127, and a lower semiconductor layer 129 of a second conductivity type. . The active layer 127 is interposed between the upper and lower semiconductor layers 125 and 129. Meanwhile, the cell isolation region 130a penetrates the light emitting cells S1 and S2 through the upper semiconductor layer 125 of the first conductivity type, the active layer 127, and the lower semiconductor layer 129 of the second conductivity type. Separate.

The active layer 127 and the upper and lower semiconductor layers 125 and 129 may be formed of a III-N-based compound semiconductor, such as (Al, Ga, In) N semiconductor. The upper and lower semiconductor layers 125 and 129 may be a single layer or multiple layers, respectively. For example, the upper and / or lower semiconductor layers 125 and 129 may include a contact layer and a cladding layer, and may also include a superlattice layer. The active layer 127 may have a single quantum well structure or a multiple quantum well structure. Preferably, the first conductivity type is n-type, and the second conductivity type is p-type. Since the upper semiconductor layer 125 may be formed of an n-type semiconductor layer having a relatively low resistance, the upper semiconductor layer 125 may have a relatively thick thickness. Therefore, it is easy to form the rough surface R on the upper surface of the upper semiconductor layer 125, the rough surface (R) improves the extraction efficiency of the light generated in the active layer 127.

The intermediate insulating layer 137 is positioned between the substrate 151 and the light emitting cells S1 and S2 to insulate the light emitting cells S1 and S2 from the substrate 151 or from the bonding metal 141. The intermediate insulating layer 137 may be a distributed Bragg reflector formed by repeatedly stacking material layers having different refractive indices, for example, SiO 2 / TiO 2 or SiO 2 / Nb 2 O 5.

The intermediate insulating layer 137 has a relatively high reflectance with respect to the light generated by the active layer 127. For example, when the active layer generates blue light, the intermediate insulating layer 137 is formed to have high reflectance for light in the wavelength range of 400 to 500 nm. In addition, since SiO2 generally has better adhesion to the semiconductor layer than TiO2 or Nb2O5, it is preferable to make SiO2 the first layer close to the light emitting cells S1 and S2.

Alternatively, the intermediate insulating layer 137 may be formed to have high reflectance for green light and red light as well as for blue light. For example, the intermediate insulating layer may be formed of a distributed Bragg reflector having a reflectance of 95% or more, more preferably 98% or more for the wavelength region of blue light, green light, and red light.

The transparent ohmic contact layer 135 is interposed between the intermediate insulating layer 137 and the light emitting cells S1 and S2. The transparent ohmic contact layer 135 may be formed of, for example, ITO or ZnO, and may ohmic contact the second conductive lower semiconductor layer 129. As illustrated in FIG. 3, the transparent ohmic contact layer 135 under the second light emitting cell S2 may extend to the cell isolation region 130a.

The reflective metal layer 138 may be interposed between the substrate 151 and the intermediate insulating layer 137. The reflective metal layer 138 reflects this light when the light generated in the active layer 127 passes through the intermediate insulating layer 137. Therefore, it is possible to prevent the light from being lost in the bonding metal 141 or the substrate 151. The reflective metal layer 138 may be formed of, for example, aluminum (Al).

The substrate 151 may be bonded to the intermediate insulating layer 137 or the reflective metal layer 138 through the bonding metal 141. An adhesive layer 139 may be interposed between the bonding metal 141 and the intermediate insulating layer 137 to improve the adhesion of the bonding metal 141. The bonding metal 141 may be formed of Au / Sn as a metal material for bonding the substrate 151 on the light emitting cells S1 and S2. Meanwhile, the adhesive layer 139 may be formed of, for example, Cr / Au.

The connection part 155 electrically connects the first conductive upper semiconductor layer 125 of the first light emitting cell S1 and the transparent ohmic contact layer 135 under the second light emitting cell S2. For example, one end of the connection portion contacts the first conductivity type upper semiconductor layer 125 of the first light emitting cell S1, extends from the one end along the side of the first light emitting cell S1, and the other end thereof. Contacts the transparent ohmic contact layer 135 extending into the cell isolation region 130a. Accordingly, the light emitting cells S1 and S2 are connected in series through the connection unit 155. Furthermore, as shown in FIG. 2, an electrode extension part 155a may be formed on the light emitting cells S1 and S2. The electrode extension part 155a is formed to assist current dispersion in the light emitting cells S1 and S2, and the structure thereof is not particularly limited. In addition, an electrode extension 155b may be formed on the transparent ohmic contact layer to increase the contact surface contacting the transparent ohmic contact layer. The electrode extensions 155a and 155b may be formed of the same material together with the connection part 155 in the same process.

Meanwhile, the first insulating layer 153 is interposed between the side surface of the first light emitting cell S1 and the connecting portion 155, and the first conductive upper semiconductor layer 125 and the second conductive type are connected by the connecting portion 155. The lower semiconductor layer 129 is prevented from being electrically shorted. The first insulating layer 153 is not particularly limited, but may be formed of SiO 2, for example.

In addition, the second insulating layer 157 may cover the first and second light emitting cells S1 and S2, the connection part 155, and the first insulating layer 153. The second insulating layer 157 may also be formed along the roughened surface of the first conductivity type upper semiconductor layer 125 to have an uneven shape. The second insulating layer 157 protects the light emitting diode from an external environment such as external force or moisture. The second insulating layer 157 may be formed of SiO 2 or Si 3 N 4.

In the present embodiment, only two light emitting cells S1 and S2 are illustrated and described, but a larger number of light emitting cells may be arranged on the substrate 151, and these light emitting cells may be connected to the plurality of connection portions 155. Via serial, parallel and / or anti-parallel connections to one another. In addition, a bridge rectifying circuit may be configured using the light emitting cells.

4 to 9 are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 4, a semiconductor stack 130 of compound semiconductor layers including a first conductive semiconductor layer 125, an active layer 127, and a second conductive semiconductor layer 129 is formed on a growth substrate 121. Is formed. The growth substrate 121 may be a sapphire substrate, but is not limited thereto and may be another hetero substrate. The first conductivity type semiconductor layer 125 is located close to the growth substrate 121. The first and second conductivity-type semiconductor layers 125 and 129 may be formed in a single layer or multiple layers, respectively. In addition, the active layer 127 may be formed in a single quantum well structure or a multiple quantum well structure.

The compound semiconductor layers may be formed of III-N-based compound semiconductors, and may be grown on the growth substrate 121 by a process such as metal organic chemical vapor deposition (MOCVD) or molecular beam deposition (MBE). Can be.

Meanwhile, before forming the compound semiconductor layers, a buffer layer (not shown) may be formed. The buffer layer is adopted to mitigate lattice mismatch between the growth substrate 121 and the compound semiconductor layers, and may be a gallium nitride-based material layer such as gallium nitride or aluminum nitride.

Referring to FIG. 5, transparent ohmic contact layers 135 spaced apart from each other are formed on the semiconductor stack 130. The transparent ohmic contact layers 135 may be formed to correspond to the light emitting cell region, and a portion of the transparent ohmic contact layers 135 may extend out of the light emitting cell region. The transparent ohmic contact layer 135 may be formed of, for example, a transparent conductive oxide film such as ITO or ZnO. The transparent ohmic contact layers 135 contact ohmic contact with the second conductive semiconductor layer 129.

Subsequently, an intermediate insulating layer 137 is formed to cover the transparent ohmic contact layer 135. The intermediate insulating layer 137 is formed of a distributed Bragg reflector in which insulating layers having different refractive indices are repeatedly stacked. For example, the intermediate insulating layer 137 may be formed by repeatedly stacking SiO 2 / TiO 2 or SiO 2 / Nb 2 O 5. By adjusting the thickness of each insulating layer forming the intermediate insulating layer 137, a distributed Bragg reflector having a high reflectance over a wide wavelength range of blue light, green light, and red light may be formed. Thereafter, a reflective metal layer 138 may be formed on the intermediate insulating layer 137. The reflective metal layer 138 may be formed of aluminum (Al), for example.

Referring to FIG. 6, an adhesive layer 139 may be formed on the reflective metal layer 138, a bonding metal 141 may be formed on the adhesive layer 139, and a secondary substrate 151 may be bonded. . The adhesive layer 139 may be formed of, for example, Cr / Au, and the bonding metal 147 may be formed of, for example, AuSn (80 / 20wt%).

Referring to FIG. 7, the growth substrate 121 is removed. The growth substrate 121 may be removed by applying a known substrate separation process, such as a laser lift off (LLO) process. As the growth substrate 121 is removed, the surface of the first conductivity-type semiconductor layer 125 is exposed.

Referring to FIG. 8, a roughened surface R may be formed on the exposed first conductive semiconductor layer 125. The roughened surface R may be formed on the entire surface of the exposed first conductivity-type semiconductor layer 125, but may be formed to be limited to a partial region as shown. For example, after forming a mask (not shown) on the first conductivity-type semiconductor layer 125 to expose a region to form a rough surface, the surface is roughened in a limited region by using photochemical (PEC) etching Can be formed.

Meanwhile, the first and second light emitting cells S1 and S2 are formed by etching the first conductive semiconductor layer 125, the active layer 127, and the second conductive semiconductor layer 129 to form a cell isolation region 130a. ). The transparent ohmic contact layer 135 under the second light emitting cell S2 is exposed by the cell isolation region 130a. In this case, the transparent ohmic contact layer 135 is formed of a transparent conductive oxide film, thereby suppressing the formation of conductive etch byproducts. Therefore, electrical short-circuit by the etching by-product of the transparent ohmic contact layer 135 is prevented.

The process of forming the roughened surface may be performed after forming the cell isolation region 130a.

9, a first insulating layer 153 covering side surfaces of the light emitting cells S1 and S2 is formed. The first insulating layer 153 may be formed of SiO 2 and covers at least some of side surfaces of the light emitting cells S1 and S2. In particular, the first insulating layer 153 may cover the bottom of the cell isolation region 130a and the inner wall of the cell isolation region 130a. Meanwhile, the first insulating layer 153 may be patterned to have an opening 153a exposing the transparent ohmic contact layer 135.

Thereafter, a connecting portion 155 is formed to electrically connect the first conductive semiconductor layer 125 of the first light emitting cell S1 and the transparent ohmic contact layer 135 exposed to the cell isolation region 130a. The connector 155 may be formed using a lift off process. While forming the connection part 155, electrode extensions (155a and 155b of FIG. 2) may be formed together.

Subsequently, a second insulating layer 157 may be formed to cover the first and second light emitting cells S1 and S2, the connection part 155, and the first insulating layer 153. The second insulating layer 157 may cover the top surface of the light emitting diode except for the electrode pads (not shown), thereby protecting the light emitting diode from the external environment.

Thereafter, an individual light emitting diode including a plurality of light emitting cells S1 and S2 is completed through a singulation process.

Claims (13)

Board;
A first light emitting cell and a second light emitting cell each including a first conductive upper semiconductor layer, an active layer, and a second conductive lower semiconductor layer;
An intermediate insulating layer disposed between the first and second light emitting cells and the substrate to insulate the first and second light emitting cells from the substrate, and a distributed Bragg reflector repeatedly stacked with an insulating layer having a different refractive index;
A transparent ohmic contact layer disposed between the intermediate insulating layer and each of the light emitting cells and contacting a second conductive lower semiconductor layer of each of the first and second light emitting cells; And
And a connector electrically connecting the first conductive upper semiconductor layer of the first light emitting cell to the transparent ohmic contact layer contacting the second conductive lower semiconductor layer of the second light emitting cell. The method according to claim 1,
The transparent ohmic contact layer is an indium tin oxide (ITO) light emitting diode. The method according to claim 1,
The light emitting diode further comprises a reflective metal layer interposed between the intermediate insulating layer and the substrate. The method according to claim 1,
The light emitting diode has a cell isolation region between the first light emitting cell and the second light emitting cell,
The transparent ohmic contact layer in contact with the second conductive lower semiconductor layer of the second light emitting cell extends to the cell isolation region. The method of claim 4,
One end of the connection part contacts the first conductive upper semiconductor layer of the first light emitting cell, the connection part extends from the one end along the side of the first light emitting cell, and the other end of the connection part is the cell. A light emitting diode in contact with the transparent ohmic contact layer in an isolation region. The method according to claim 5,
And a first insulating layer interposed between the connecting portion and the side surface of the first light emitting cell to insulate the connecting portion from the side surface of the first light emitting cell. The method of claim 6,
And a second insulating layer covering the connection part together with the first light emitting cell and the second light emitting cell. The method of claim 7,
The first conductive upper semiconductor layer of the first and second light emitting cells has a roughened surface,
The second insulating layer covers a roughened surface of the first conductive upper semiconductor layer, wherein the surface of the second insulating layer has a concave-convex shape along the roughened surface of the first conductive upper semiconductor layer. Growing a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on the growth substrate;
Forming transparent ohmic contact layers spaced apart from each other on the second conductivity type semiconductor layer,
Repeatedly stacking insulating layers having different refractive indices on the transparent ohmic contact layers to form an intermediate insulating layer of a distributed Bragg reflector covering the transparent ohmic contact layers,
Bonding a secondary substrate on the intermediate insulating layer,
Removing the growth substrate to expose a first conductivity type semiconductor layer,
A cell isolation region is formed to etch the first conductivity type semiconductor layer, the active layer, and the second conductivity type semiconductor layer to define a first light emitting cell and a second light emitting cell. The transparent ohmic contact layer is exposed,
Forming a first insulating layer covering at least part of side surfaces of the first and second light emitting cells,
And forming a connection portion electrically connecting the first conductive semiconductor layer of the first light emitting cell to the transparent ohmic contact layer under the second light emitting cell. The method according to claim 9,
The transparent ohmic contact layer is ITO. The method according to claim 9,
Before bonding the secondary substrate, further comprising forming a reflective metal layer on the intermediate insulating layer. The method according to claim 9,
And forming a roughened surface on the exposed first conductive semiconductor layer. The method of claim 12,
The method may further include forming a second insulating layer covering the connection part together with the first and second light emitting cells.
The second insulating layer is formed along the rough surface of the first conductive semiconductor layer has a concave-convex shape.

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