KR20180078941A - Light emitting diode device for active matrix displays and manufacturing method thereof - Google Patents

Abstract

An LED element for active matrix display comprises: a light emitting diode including an epitaxial layer in which an n-type semiconductor layer, an active layer of a quantum well structure and a p-type semiconductor layer are sequentially stacked; an insulating layer formed in a predetermined region on the epitaxial layer; and a TFT formed on the insulating layer in order to drive the light emitting diode. According to the present invention, a large-area display can be realized without limitation on the size and material of a substrate, individual chips having high light efficiency with a high integration degree can be applied without using a wavelength conversion technique, and manufacturing costs and process costs can be reduced.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an active matrix display (LED)

The present invention relates to an LED element for an active matrix display and a method of manufacturing the same. More particularly, the present invention relates to an LED device for an active matrix display including a TFT (Thin Film Transistor) for driving a light emitting diode (LED) in a single chip, and a manufacturing method thereof.

In general, an active matrix type display exhibits better characteristics in terms of response speed, contrast, and viewing angle as compared to a passive matrix type display. A thin film transistor (hereinafter referred to as "TFT") is used as a switching element in an active matrix driving type display device, and AMOLED (Active Matrix OLED) is a typical active matrix type display .

Patent Document 1 discloses a manufacturing process of an AMOLED (Active Matrix OLED). In an initial stage of a manufacturing process, a TFT is manufactured first and a light emitting portion is formed on the TFT. However, in the case of active displays using inorganic LEDs, for example, GaN or GaAs-based LEDs, it is very important to grow high-quality epitaxial layers on a single-crystal growth substrate. It is impossible to grow high quality epi on it.

Therefore, in the non-patent document 1, the LED manufacturing process is not included in the display manufacturing process, the LED is separately manufactured, and then the Si CMOS device is electrically connected through wafer bonding to realize the active display. Micro LEDs fabricated in this way have a very high pixel density and thus have a very high value of ppi (pixel per inch), which is suitable for mobile devices, but is not suitable for large-area display implementations.

In addition, in the non-patent document 1, a monochromatic element based on GaN is implemented on a sapphire substrate to realize only a monochromatic wavelength. Therefore, when individual LEDs of different wavelengths are used, wafer bonding is not possible, so that an active display can not be realized. Therefore, it is necessary to assemble the TFT device separately manufactured for each LED, but this requires a millions of individual TFT device packages, which increases the cost and increases the manufacturing time.

Also, in the display of the non-patent document 1, the Si CMOS device located below is implemented on the Si substrate, and the LED device located on the upper side is implemented on the sapphire substrate, so that the active matrix display can not be realized on the flexible substrate.

In the non-patent document 2, a passive matrix display using individual micro LEDs is implemented on a flexible substrate. However, there are technical difficulties in that it is impossible to perform active driving and a TFT device must be additionally mounted on a flexible substrate. It has a disadvantage in that it is difficult to apply it to a display having a high degree of integration because it occupies a large area on the same horizontal plane.

Korean Patent No. 10-1222540

 &Quot; III-Nitride full-scale high-resolution microdisplays ", APL 99, 031116 (2011)  "Printed Assemblies of Inorganic LEDs for Deformable and Semitransparent Displays", Science 325, 977 (2009)

A first aspect of the present invention is to provide a display device capable of realizing a large-area display without being limited by the size and material of a substrate by incorporating a TFT in the LED chip, enabling application of individual chips having excellent light efficiency without using a wavelength conversion technique, An LED element for an active matrix display capable of being implemented on a substrate is proposed.

A second aspect of the present invention is to propose a method of manufacturing an LED element for an active matrix display capable of reducing manufacturing cost and process time by avoiding the inconvenience of assembling individual LEDs in a separately manufactured TFT element.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a first aspect of the present invention is a light emitting diode comprising: an LED including an n-type semiconductor layer, an active layer of a quantum well structure and a p-type semiconductor layer sequentially laminated; An insulating layer formed in a predetermined region on the epi layer; And a TFT formed on the insulating layer, wherein the TFT is for driving the light emitting diode.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: preparing a growth substrate including an epitaxial layer in which an n-type semiconductor layer, an active layer of a quantum well structure and a p-type semiconductor layer are sequentially formed; Etching the mesa to expose a portion of the n-type semiconductor layer; Forming an insulating layer on the p-type semiconductor layer or on the n-type semiconductor layer; Implementing a TFT on the insulating layer; And forming a cathode electrode and an anode electrode. The present invention also provides a method of manufacturing an LED element for an active matrix display.

According to the present invention, it is possible to realize a large-area display without limitation on the size and material of the substrate, to apply individual chips having high integration efficiency and high optical efficiency without using a wavelength conversion technique, An LED element for an active matrix display can be provided.

FIGS. 1A to 1E are diagrams showing the steps of a manufacturing process of an LED device for an active matrix display according to a first embodiment of the present invention.
2 is a configuration diagram of an LED element for an active matrix display, manufactured according to a second embodiment of the present invention.
3 is a configuration diagram of an LED element for an active matrix display, manufactured according to a third embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

It is to be understood that throughout the specification, when a member is located on another member "above," "above," "above," "below" or "under" And the case where another member exists between the two members.

On the other hand, any member referred to as "directly on" or "directly above"

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

Furthermore, terms including ordinals such as first, second, etc. used in this specification can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The present invention intends to provide a micro LED structure in which a TFT element is implemented on an LED chip for an active matrix display and a manufacturing method thereof. By embedding an active TFT element driving an LED in an LED chip, an active display can be realized and overcome the disadvantage of a passive type display using a conventional micro LED.

For this purpose, the LED device for active matrix display proposed in the present invention includes a TFT for driving a light emitting diode in a chip, and the light emitting diode includes an n-type semiconductor layer, an active layer having a quantum well structure and a p- And the TFT is formed on the insulating layer so as to be protected by an insulating layer formed in a certain region on the epi layer. The TFT performs a function of driving the light emitting diode.

The light emitting diode may be formed on a growth substrate, and the growth substrate may be selected from the group consisting of sapphire, silicon carbide, zinc oxide, gallium nitride, aluminum nitride, zirconium diboride, gallium arsenide, and silicon. It is not. Specifically, in addition to sapphire, other different substrates such as glass, silicon carbide, silicon, GaAs, GaP, AlGaINP, Ge, SiSe, GaN, AlInGaN and InGaN may be used.

The light emitting diode formed on the growth substrate may have an epitaxial layer, and may have a single or multiple quantum well structure between the n-type semiconductor layer as the electron injection layer and the p-type semiconductor layer as the hole injection layer. Lt; / RTI > The n- type and p- type semiconductor layer and the active layer is, Al _x In _y Ga _(1-xy) N composition formula (where, 0≤x≤1, 0≤y≤1, 0≤x + y≤1 Im) But is not limited thereto. Thus, the epitaxial layer may be formed of a GaN-based material and may be implemented as a GaN-based LED (uv to blue and green, 230 nm to 540 nm). However, in addition to the GaN-based materials, GaAs and InP-based materials may also be used. In this specification, a representative example of the epitaxial layer is a GaN-based epitaxial layer and will be mainly described. However, it is not intended to exclude that an epitaxial layer is composed of a material other than GaN.

At this time, one side of the p-type semiconductor layer and the active layer is mesa-etched so that a part of the n-type semiconductor layer is exposed.

As the insulating layer, a passivation layer made of SiO ₂ can be formed by a PECVD method. The insulating layer functions to protect the TFT.

The TFT including the insulating layer may be formed on the p-type semiconductor layer or on the n-type semiconductor layer.

Hereinafter, the manufacturing method and the structure of the LED device manufactured through the method of forming the TFT on the p-type semiconductor layer and the case of forming on the n- type semiconductor layer will be described with reference to examples.

[ Example 1 ] TFT is n- type Semiconductor layer  When formed on the top

Figs. 1A to 1E show an LED element manufacturing process in the case where the TFT is formed on the n-type semiconductor layer.

Referring to FIG. 1E, the TFT includes a drain electrode and a source electrode spaced apart from each other on the insulating layer, and is formed on the insulating layer so as to contact at least a part of each of the drain electrode and the source electrode. (Semiconductor thin film for TFT). Further, a gate insulating film and a gate electrode are sequentially formed on the semiconductor thin film.

An anode electrode is formed on the p-type semiconductor layer, and a cathode electrode is formed on the n-type semiconductor layer. The drain electrode and the cathode electrode are electrically connected to each other.

Further, a transparent conductive oxide thin film (hereinafter also referred to as a transparent electrode) is additionally provided between the anode electrode and the p-type semiconductor layer. In FIG. 1E, ITO is provided as an example of the transparent conductive oxide thin film.

In order to fabricate an LED device having such a structure, a growth substrate (for example, Sapphire) including an epitaxial layer in which an n-type semiconductor layer, an active layer having a quantum well structure and a p-type semiconductor layer are sequentially formed is prepared . Then, a mesa etching is performed so that a part of the n-type semiconductor layer is exposed. (See Fig. 1A)

A transparent electrode (or a transparent conductive oxide thin film) is formed on a part of the p-type semiconductor layer immediately above the p-type semiconductor layer. At this time, the transparent conductive oxide can be deposited by an electron beam evaporation method using a negative PR (photoresist), and the PR can be lifted off. The transparent conductive oxide may be made of any one of ITO, CIO, ZnO, NiO, and In ₂ O _3. The transparent conductive oxide may include In, Sn, Al, Zn and Ga. (See FIG. 1A), an ohmic contact is formed between the transparent electrode and the p-type semiconductor layer in the heat treatment process.

Then, an insulating layer is deposited on the entire surface, and a transparent electrode region is exposed by a photolithography process and a patterning process through etching. Further, the insulating layer over the n-type semiconductor layer is opened. The insulating layer may be formed by a PECVD method or the like, but is not limited thereto, by using a passivation layer made of an insulating material such as SiO ₂ . (See FIG. 1B)

Thereafter, an anode electrode is formed on the p-type semiconductor layer via the transparent electrode through a photolithography process. Also, a part of the insulating layer on the n-type semiconductor layer is opened through a photolithography process, and n-metal is deposited to form a cathode electrode. In the process of forming the cathode electrode, rapid thermal annealing (RTA) is further performed. (See FIG. 1B)

Then, a TFT is formed on the insulating layer formed on the n-type semiconductor layer. To this end, a TFT semiconductor thin film is first formed on the insulating layer formed on the n-type semiconductor layer. (See Fig. 1C)

As the semiconductor thin film for TFT formed on the insulating layer, known materials used as a semiconductor thin film of a conventional TFT element can be used. For example, the semiconductor thin film may be formed of low-temperature polycrystalline silicon (LTPS); Si; Carbon nanotubes; Graphene; 12, 13, and 14 metal elements, and combinations thereof. However, the present invention is not limited thereto. Examples of the Group 12, 13, and 14 metal elements include Zn, In, Ga, Cd, Ge, and Hf. have.

In the case of a semiconductor thin film, a known film forming method can be used, and a physical film forming method other than a chemical film forming method such as a spray method and a CVD method can also be used. Examples of the physical film forming method include a sputtering method, a vacuum deposition method, an ion plating method, and a pulse laser deposition method.

The semiconductor thin film is deposited on the entire surface like the insulating layer, and the remaining region except the region for forming the TFT is removed on the n-type semiconductor layer by a photolithography process and a patterning process by etching. The semiconductor thin film formed on the upper insulating layer of the n-type semiconductor layer may undergo an activation process. For example, in the case of LTPS, polycrystallization can be performed using a laser.

After the semiconductor thin film is formed, a gate insulating film is formed on the semiconductor thin film. (See Fig. 1d)

The material for forming the gate insulating film is not particularly limited. Those generally used in the range of not losing the effect of the invention of the present embodiment can be arbitrarily selected. For _{example, SiO 2, SiN x, Al} 2 O 3, Ta 2 O 5, TiO 2, MgO, ZrO 2, CeO 2, K 2 O, Li 2 O, Na 2 O, Rb 2 O, Sc 2 O ₃ , Y ₂ O ₃ , Hf ₂ O ₃ , CaHfO ₃ and the like can be used. Of these, SiO ₂ , SiN _x , Al ₂ O ₃ , Y ₂ O ₃ , Hf ₂ O ₃ and CaHfO ₃ are preferably used, and SiO ₂ , SiN _x , Y ₂ O ₃ , Hf ₂ O ₃ , CaHfO ₃ , and particularly preferably SiO ₂ and SiN _x .

The gate insulating film can be formed by various deposition methods such as sputtering, chemical vapor deposition (CVD), or plasma enhanced chemical vapor deposition (PECVD).

The gate insulating film can be patterned through a photolithography process and etching.

After the formation of the gate insulating film, a source electrode, a drain electrode, and a gate electrode are formed. (See FIG. 1E). At this time, the drain electrode of the TFT is formed to be in contact with or electrically connected to the cathode electrode.

The material for forming the respective electrodes of the source electrode and the drain electrode is not particularly limited and those generally used within the range in which the effect of the present embodiment is not lost can be arbitrarily selected. For example, transparent electrodes such as ITO, IZO, ZnO and SnO ₂ , metal electrodes such as Al, Ag, Cr, Ni, Mo, Au, Ti and Ta, . Each electrode of the source electrode and the drain electrode may have a multilayer structure in which two or more different conductive layers are stacked.

In the case of forming the source electrode and the drain electrode, a method such as a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, a chemical method such as CVD (Chemical Vapor Deposition) The film may be formed in accordance with a method appropriately selected in consideration of suitability with the material to be used.

The source electrode and the drain electrode may be formed by patterning in a predetermined shape by, for example, etching or lift-off after forming a conductive film, or may be formed by direct patterning by an inkjet method or the like.

The source electrode and the drain electrode face each other around the semiconductor thin film and are electrically connected to the semiconductor thin film.

The gate electrode may be formed of a material having high conductivity, for example, a metal such as Al, Cu, Mo, Cr, Ta, Ti, Ag, or Au, an Al-Nd, Ag alloy, tin oxide, zinc oxide, A metal oxide conductive film such as indium tin oxide (ITO), zinc oxide indium (IZO), or In-Ga-Zn-O can be used.

The gate electrode is appropriately selected in consideration of suitability with a material to be used in a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, or a chemical method such as a CVD method or a plasma CVD method The film is formed according to the method.

After the film formation, the gate electrode may be formed by patterning in a predetermined shape by an etching or lift-off method, or may be directly pattern-formed by an ink-jet method, a printing method, or the like.

[ Example 2 ] TFT is a p-type Semiconductor layer  When formed on the top

Fig. 2 shows the structure of the LED element in the case where the TFT is formed on the p-type semiconductor layer.

2, the TFT includes a drain electrode and an anode electrode spaced apart from each other on the insulating layer, and a semiconductor thin film (TFT) is formed so as to contact at least a part of each of the drain electrode and the anode electrode. A semiconductor thin film), and a gate insulating film and a gate electrode are sequentially formed on the semiconductor thin film.

In addition, a source electrode is provided on the n-type semiconductor layer, and a cathode electrode is formed on the p-type semiconductor layer. The drain electrode and the cathode electrode are connected to each other.

In addition, a transparent conductive oxide thin film (for example, ITO) is further provided on the p-type semiconductor layer to be connected to the cathode electrode. In this case, the light is emitted in the direction in which the TFT element is formed.

In order to manufacture an LED device having such a structure, a growth substrate including an epitaxial layer in which an n-type semiconductor layer, an active layer having a quantum well structure and a p-type semiconductor layer are sequentially formed is prepared. Then, a mesa etching is performed so that a part of the n-type semiconductor layer is exposed.

A transparent electrode is formed on a part of the p-type semiconductor layer immediately above the p-type semiconductor layer. At this time, a transparent conductive oxide can be deposited by electron beam evaporation using a negative PR (photoresist), lift-off of PR, and ohmic contact can be formed by a heat treatment process. The material of the transparent conductive oxide is the same as that described in the first embodiment.

Then, an insulating layer is deposited on the entire surface, and a transparent electrode region is exposed by a photolithography process and a patterning process through etching. Further, the insulating layer over the n-type semiconductor layer is opened. The material and method of forming the insulating layer and the transparent electrode can utilize the contents described in the first embodiment.

A source electrode is formed in a region where the insulating layer on the n-type semiconductor layer is open. As for the material and the forming method of the source electrode, the above-described contents can be utilized in the first embodiment.

A TFT is formed on the insulating layer formed on the p-type semiconductor layer. To this end, a TFT semiconductor thin film is first formed on the insulating layer formed on the p-type semiconductor layer. As for the material and the forming method of the semiconductor thin film, the above-mentioned contents can be utilized in the first embodiment.

After the semiconductor thin film is formed, a gate insulating film is formed on the semiconductor thin film. As for the material and the formation method of the gate insulating film, the above-described contents can be utilized in the first embodiment.

After the formation of the gate insulating film, an anode electrode, a drain electrode, and a gate electrode are formed. A gate electrode is formed on the gate insulating film. The anode electrode and the drain electrode face each other with respect to the semiconductor thin film and are electrically connected to the semiconductor thin film. At this time, the drain electrode of the TFT is formed to be in contact with or electrically connected to the cathode electrode.

[ Example 3 ] TFT is a p-type Semiconductor layer  When formed on the top

Fig. 3 shows the structure of the LED element in the case where the TFT is formed on the p-type semiconductor layer.

3, the TFT includes a drain electrode and an anode electrode spaced apart from each other on the insulating layer, and a semiconductor thin film (TFT) is formed so as to contact at least a part of each of the drain electrode and the anode electrode. A semiconductor thin film), and a gate insulating film and a gate electrode are sequentially formed on the semiconductor thin film.

Also, a source electrode is provided on the n-type semiconductor layer. A cathode electrode is formed on the p-type semiconductor layer, and the drain electrode and the cathode electrode are connected to each other.

Further, a metal reflector is additionally provided between the p-type semiconductor layer and the insulating layer, and the metal reflection layer is connected to the cathode electrode. In this case, the light is emitted in a direction opposite to the direction in which the TFT element is formed.

In order to manufacture an LED device having such a structure, a growth substrate including an epitaxial layer in which an n-type semiconductor layer, an active layer having a quantum well structure and a p-type semiconductor layer are sequentially formed is prepared. Then, a mesa etching is performed so that a part of the n-type semiconductor layer is exposed.

A metal reflection layer is formed on a part of the p-type semiconductor layer immediately above the p-type semiconductor layer. For this purpose, metal is deposited using PR (photoresist). The metal reflective layer reflects the light emitted from the light emitting portion so that the light can be effectively diverted and at the same time forms an ohmic contact with the p-type semiconductor to smooth current injection and lower the operating voltage. As the metal reflective layer, a material having high reflectivity such as aluminum (Al), gold, copper, and nickel may be used in addition to silver (Ag) having high reflectivity. In order to form Ohmic Contact, a small amount of metals such as Ni, Pd, Cr, Co, Au, and Pt, or a mixture of two or more of these metals is very thin (<2 nm) Can be deposited before the reflective layer is formed. After the metal deposition, a heat treatment process is performed to form Ohmic Contact.

Subsequently, an insulating layer is deposited on the entire surface, and a part of the metal reflection layer is exposed by a photolithography process and a patterning process by etching. Further, the insulating layer over the n-type semiconductor layer is opened. The material of the insulating layer and the method of forming the same can be utilized in the first embodiment.

A source electrode is formed in a region where the insulating layer on the n-type semiconductor layer is open. As for the material and the forming method of the source electrode, the above-described contents can be utilized in the first embodiment.

A TFT is formed on the insulating layer formed on the p-type semiconductor layer via the metal reflection layer. To this end, a TFT semiconductor thin film is first formed on the insulating layer formed on the p-type semiconductor layer. As for the material and the forming method of the semiconductor thin film, the above-mentioned contents can be utilized in the first embodiment.

After the semiconductor thin film is formed, a gate insulating film is formed on the semiconductor thin film. As for the material and the formation method of the gate insulating film, the above-described contents can be utilized in the first embodiment.

After the formation of the gate insulating film, an anode electrode, a drain electrode, and a gate electrode are formed. A gate electrode is formed on the gate insulating film. The anode electrode and the drain electrode face each other with respect to the semiconductor thin film and are electrically connected to the semiconductor thin film. At this time, the drain electrode of the TFT is formed to be in contact with or electrically connected to the cathode electrode.

Various embodiments of the LED element for active matrix display in which a TFT is incorporated as a driving element through Embodiments 1 through 3 have been described and a manufacturing method thereof has been described. The LED device for active matrix display manufactured by the above-described method may be implemented as a horizontal structure, a vertical structure, or a flip chip structure.

As described above, after the TFT is implemented in the LED device, the growth substrate can be separated into individual LED chips by performing the gilding / lapping and the dicing process of the growth substrate. The characteristics of the thus fabricated device are as follows: an insulating layer is deposited on the upper surface of each LED element to electrically isolate the LED layer from the LED electrode, and then a TFT is formed on the upper surface of the insulating layer, And a built-in drive circuit. In addition, both the electrodes of the LED element and the electrodes of the TFT element are located above the LED chip, and can be mounted on the display panel by an individual LED chip bonding process.

As described above, since the LED chip mounted with the TFT is used, the individual LED chip can be mounted at a desired position, and the active matrix display can be realized without being limited by the display size. In this case, since it uses individual LED chips, it is possible to realize a large-sized display of several tens of meters which can not be implemented in AMOLED.

In addition, since sapphire-based GaN LEDs are mainly used in an active matrix display using a conventional micro LED, a wavelength conversion technology such as a quantum dot is indispensable for full-color implementation. However, since the LED chip of the present invention can use different LED chips for different wavelengths of red, blue, and green, and includes an active element, it is possible to apply an individual LED chip having excellent light efficiency without using wavelength conversion technology, Implementation is possible.

In the case of a flexible display using a micro LED, the display can be implemented only as a passive matrix display. However, when the LED chip of the present invention is used, a flexible active matrix display using a micro LED can be realized.

In the manufacturing process, conventionally, a TFT element for driving an LED was manufactured separately and assembled to a panel. Therefore, it was inevitable to reduce the yield due to the increase in the unit price and the addition of the panel manufacturing process. However, in the present invention, The process time is shortened, the unit cost is reduced, and it is possible to contribute to miniaturization of the device.

Claims (16)

a light emitting diode including an epi layer in which an n-type semiconductor layer, an active layer of a quantum well structure and a p-type semiconductor layer are sequentially stacked;
An insulating layer formed in a predetermined region on the epi layer; And
And a TFT formed on the insulating layer,
And the TFT is for driving the light emitting diode. The method according to claim 1,
Wherein the light emitting diode is in the form of a mesa etched so that a part of the n-type semiconductor layer is exposed. 3. The method of claim 2,
And the TFT including the insulating layer is formed on the p-type semiconductor layer or on the n-type semiconductor layer. The method of claim 3,
When the TFT is formed on the n-type semiconductor layer, the TFT has a drain electrode and a source electrode spaced from each other on the insulating layer, and the semiconductor thin film is contacted with at least a part of each of the drain electrode and the source electrode. And a gate insulating film and a gate electrode sequentially formed on the semiconductor thin film,
Type semiconductor layer, an anode electrode on the p-type semiconductor layer, and a cathode electrode on the n-type semiconductor layer, wherein the drain electrode and the cathode electrode are connected to each other. 5. The method of claim 4,
Further comprising a transparent conductive oxide thin film between the anode electrode and the p-type semiconductor layer. The method of claim 3,
When the TFT is formed on the p-type semiconductor layer, the TFT includes a drain electrode and an anode electrode spaced apart from each other on the insulating layer, and the semiconductor thin film is contacted with at least a part of each of the drain electrode and the anode electrode. And a gate insulating film and a gate electrode sequentially formed on the semiconductor thin film,
And a source electrode on the n-type semiconductor layer, and a cathode electrode on the p-type semiconductor layer, wherein the drain electrode and the cathode electrode are connected to each other. The method according to claim 6,
And a transparent conductive oxide thin film connected to the cathode electrode on the p-type semiconductor layer. The method according to claim 6,
And a metal reflection layer is further provided between the p-type semiconductor layer and the insulating layer, and the metal reflection layer is connected to the cathode electrode. The method according to claim 4 or 6,
Wherein the semiconductor thin film comprises LTPS; Si; Carbon nanotubes; Graphene; 12, 13, and 14 metal elements, and combinations thereof. The method according to claim 1,
And the TFT is protected by an insulating layer formed in a certain region on the epi layer. preparing a growth substrate including an epitaxial layer in which an n-type semiconductor layer, an active layer of a quantum well structure and a p-type semiconductor layer are sequentially formed;
Etching the mesa to expose a portion of the n-type semiconductor layer;
Forming an insulating layer on the p-type semiconductor layer or on the n-type semiconductor layer;
Implementing a TFT on the insulating layer; And
And forming a cathode electrode and an anode electrode. 12. The method of claim 11,
In the case where the TFT including the insulating layer is formed on the n-type semiconductor layer, the anode electrode is formed on the p-type semiconductor layer before the TFT is formed after the insulating layer is formed, Type semiconductor layer, and the cathode electrode is formed to be connected to the drain electrode of the TFT. 13. The method of claim 12,
Further comprising forming a transparent conductive oxide thin film directly on the p-type semiconductor layer before forming the anode electrode on the p-type semiconductor layer. 12. The method of claim 11,
A source electrode is formed on the n-type semiconductor layer and the p-type semiconductor layer is formed before the TFT is formed after the insulating layer is formed, when the TFT including the insulating layer is formed on the p- Type semiconductor layer, and the cathode electrode is formed to be connected to the drain electrode of the TFT. 15. The method of claim 14,
Further comprising forming a transparent conductive oxide thin film directly on the p-type semiconductor layer before forming the cathode electrode on the p-type semiconductor layer, the transparent conductive oxide thin film being connected to the cathode electrode. Gt; 15. The method of claim 14,
Further comprising forming a metal reflection layer directly on the p-type semiconductor layer before forming the cathode electrode on the p-type semiconductor layer, the metal reflection layer being connected to the cathode electrode. .

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