KR20240098883A - Semiconductor light emitting device for pixel and display device including the same - Google Patents

Abstract

A semiconductor light emitting device for a pixel according to an embodiment includes a light emitting structure including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer; a reflective insulating layer surrounding a portion of the light emitting structure; and an insulating layer disposed on the reflective insulating layer. The reflective insulating layer may be disposed by stacking a plurality of layers.

Description

Semiconductor light emitting device for pixel and display device including the same}

The embodiment relates to a semiconductor light emitting device for a pixel and a display device including the same.

Large-area displays include liquid crystal displays (LCDs), OLED displays, and Micro-LED displays.

A micro-LED display is a display that uses micro-LED, a semiconductor light emitting device with a diameter or cross-sectional area of 100㎛ or less, as a display element.

Because micro-LED displays use micro-LED, a semiconductor light-emitting device, as a display device, they have excellent performance in many characteristics such as contrast ratio, response speed, color gamut, viewing angle, brightness, resolution, lifespan, luminous efficiency, and luminance.

In particular, the micro-LED display has the advantage of being able to freely adjust the size and resolution and implement a flexible display because the screen can be separated and combined in a modular manner.

On the other hand, in micro-LED displays, light coming from the front is important, but a problem may arise where a lot of light escapes from the sides and bottom. Therefore, it is necessary to improve the luminance in front of the display.

Additionally, in the display process, micro-LEDs may be damaged, causing problems with light emission or reliability, so technology to prevent this is needed.

The embodiments aim to solve the above-described problems and other problems.

Another purpose of the embodiment is to improve the brightness of the semiconductor light emitting device.

Additionally, another purpose of the embodiment is to improve light output.

Additionally, another purpose of the embodiment is to block leakage current.

Additionally, another purpose of the embodiment is to prevent damage to the LED chip in the display panel device.

Additionally, another purpose of the embodiment is to prevent poor lighting of the LED chip.

A semiconductor light emitting device for a pixel according to an embodiment includes a light emitting structure including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer; a reflective insulating layer surrounding a portion of the light emitting structure; and an insulating layer disposed on the reflective insulating layer. The reflective insulating layer may be disposed by stacking a plurality of layers.

Additionally, in an embodiment, the insulating layer may expose a portion of the reflective insulating layer.

Additionally, the embodiment may further include a current blocking layer that is disposed below the active layer and blocks current flowing from the active layer to the side.

Additionally, the embodiment may further include a reflective layer disposed below the active layer.

Additionally, in an embodiment, the reflective insulating layer may include an oxide material.

Additionally, in an embodiment, the reflective insulating layer may be formed by alternately stacking TiO ₂ /SiO ₂ .

Additionally, in an embodiment, the reflective insulating layer may cover a side of the light emitting structure.

Additionally, in an embodiment, the reflective insulating layer may be disposed to extend from the side of the first conductive semiconductor layer to the second conductive semiconductor layer.

Additionally, in embodiments, the reflective insulating layer may include materials with different refractive indices.

Additionally, a display device including a semiconductor light emitting device according to an embodiment includes a substrate having a plurality of assembly wirings; a partition disposed on the substrate and having an assembly hole; And it may include a semiconductor light emitting device for a pixel according to any one of claims 1 to 9 disposed in the assembly hole.

The semiconductor light emitting device for pixels according to the embodiment and the display device including the same have a technical effect of improving luminance.

Additionally, the embodiment has a technical effect that can improve light output.

For example, in an embodiment, the DBR layer is made of materials with different refractive indices so that light that escapes from the bottom and sides of the chip can be reflected upward.

Additionally, the embodiment has the technical effect of protecting the LED chip during the display panel process after assembling the LED chip into the panel.

Additionally, the embodiment has the technical effect of blocking leakage current.

For example, in the embodiment, the passivation layer is formed of a plurality of layers, and a current blocking layer can be formed to block leakage current.

Additionally, the embodiment has the technical effect of preventing damage to the LED chip by penetrating the chemical solution through the pinhole.

For example, in the embodiment, the passivation layer is formed by alternately depositing a plurality of layers, so that pin holes are not connected between layers, so chemical solutions or gases cannot penetrate.

Additionally, the embodiment has the technical effect of preventing lighting defects in the LED chip.

For example, the embodiment can prevent lighting defects in LED chips because the issue of damage to the light emitting structure is significantly reduced even if the panel process progresses.

Additional scope of applicability of the embodiments will become apparent from the detailed description that follows. However, since various changes and modifications within the spirit and scope of the embodiments may be clearly understood by those skilled in the art, the detailed description and specific embodiments, such as preferred embodiments, should be understood as being given by way of example only.

1A to 1D are diagrams showing defect issues of semiconductor light emitting devices and passivation layers in undisclosed internal technology.
Figure 2 is a cross-sectional view of a semiconductor light-emitting device for a pixel according to the first embodiment.
3 is a cross-sectional view of a semiconductor light-emitting device for a pixel according to a second embodiment.
Figure 4 is a cross-sectional view of a semiconductor light emitting device for a pixel according to a third embodiment.
5A to 5D are diagrams showing the manufacturing process of a semiconductor light emitting device for a pixel according to the first embodiment.
6 shows a display device including a semiconductor light-emitting device for a pixel according to a third embodiment.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. However, identical or similar components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted. The suffixes 'module' and 'part' for components used in the following description are given or used interchangeably in consideration of ease of specification preparation, and do not have distinct meanings or roles in themselves. In addition, the attached drawings are intended to facilitate easy understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the attached drawings. Additionally, when an element such as a layer, region or substrate is referred to as being 'on' another component, this includes either directly on the other element or there may be other intermediate elements in between. do.

Display devices described in this specification include TVs, shines, mobile terminals such as mobile phones and smart phones, displays for computers such as laptops and desktops, head-up displays (HUDs) for automobiles, backlight units for displays, It may include displays, light sources, etc. for VR, AR, or MR (mixed reality). However, the configuration according to the embodiment described in this specification can be applied to a device capable of displaying even if it is a new product type that is developed in the future.

Figures 1A to 1D are diagrams showing defect issues in semiconductor light emitting device and display processes that were studied privately.

Referring to FIG. 1A, a light emitting structure 20 is formed on a substrate 10, and a passivation layer 40 may cover the light emitting structure 20. Additionally, electrodes may be formed on a portion of the light emitting structure 20. However, when using a semiconductor light emitting device as a display pixel, a process for assembling the semiconductor light emitting device on a panel substrate and a panel process may be performed.

For example, the substrate can be removed using a laser-lift-off (LLO) or chemical lift-off (CLO) process. However, in the process of removing the semiconductor light emitting device from the growth substrate, the passivation layer 40 may be damaged by a laser or chemical solution. Thereafter, the passivation layer 40 may be physically damaged during the process of assembling the semiconductor light emitting device removed from the growth substrate to the panel substrate. Additionally, in the process of forming the panel electrode, the passivation layer 40 may suffer physical or chemical damage due to etching, photo processing, etc.

Referring to FIG. 1B, as the passivation layer 40 is damaged during the process, a portion of the passivation layer 40 may be lost and the light emitting structure 20 present inside may be exposed. The exposed light emitting structure 20 is not protected during the subsequent panel process, and problems such as deterioration in electrical, optical, and structural performance may occur.

Next, referring to FIG. 1C, the passivation layer 40 of the semiconductor light emitting device, which is being studied internally and privately, may be formed of a single layer of oxide, and pin holes 45, which are fine holes, may be formed throughout the passivation layer. You can. The pin holes 45 are arranged irregularly, and several pin holes 45 can be combined to form a larger pin hole. Thereafter, during the panel process, chemical solution or gas may flow into the pin hole 45 and cause damage to the light emitting structure. Additionally, along with damage to the passivation layer, the degree of exposure of the light emitting structure may increase.

In this case, the conductive semiconductor layer or active layer directly in contact with the inside of the passivation layer 40 may be exposed to the chemical solution and be damaged, which may not only reduce light efficiency but also cause lighting problems. In addition, a damaged single-layer oxide layer may cause leakage current when driven at low current, resulting in a decrease in electrical characteristics.

Also, referring to FIG. 1D, in the normal chip of FIG. 1D (a), all light emitting areas can fully emit light, but when the light emitting structure is damaged like the defective chip in FIG. 1D (b), one area or the entire area emits light. Light emission defects may occur, which may lead to poor lighting of the LED chip.

Hereinafter, a semiconductor light emitting device for a pixel according to an embodiment to solve the above problem will be described.

Figure 2 is a cross-sectional view of a semiconductor light emitting device according to the first embodiment. Referring to FIG. 2, the semiconductor light emitting device 150 may include a light emitting structure 120, a reflective insulating layer 130, a first electrode 155, a second electrode 153, and an insulating layer 140. . The light emitting structure 120 includes a first conductive semiconductor layer 121, an active layer 122 disposed on the first conductive semiconductor layer 121, and a second conductive semiconductor disposed on the active layer 122. It may include a layer 123.

The first conductive semiconductor layer 121 may be an n-type semiconductor layer, and the second conductive semiconductor layer 123 may be a p-type semiconductor layer, but are not limited thereto. The first conductive semiconductor layer 121, the active layer 122, and the second conductive semiconductor layer 123 may be made of a compound semiconductor material. For example, the compound semiconductor material may be a group 3-5 compound semiconductor material, a group 2-6 compound semiconductor material, etc. For example, the compound semiconductor material may include GaN, InGaN, AlN, AlInN, AlGaN, AlInGaN, InP, GaAs, GaP, GaInP, etc.

For example, the first conductivity type semiconductor layer 121 may include a first conductivity type dopant, and the second conductivity type semiconductor layer 123 may include a second conductivity type dopant. For example, the first conductivity type dopant may be an n-type dopant such as silicon (Si), and the second conductivity type dopant may be a p-type dopant such as boron (B).

The active layer 122 is a region that generates light and can generate light with a specific wavelength band depending on the material properties of the compound semiconductor. That is, the wavelength band can be determined by the energy band gap of the compound semiconductor included in the active layer 122. Therefore, depending on the energy band gap of the compound semiconductor included in the active layer 122, the semiconductor light emitting device 150 of the embodiment may generate UV light, blue light, green light, and red light.

A transparent electrode layer 124 may be disposed on the second conductive semiconductor layer 123. The transparent electrode layer 124 is made of a light-transmitting material so that light generated in the active layer can be emitted to the top of the semiconductor light-emitting device. For example, it may be made of ITO (Indium Tin Oxide), but is not limited thereto. The transparent electrode layer 124 can later electrically connect the panel electrode and the second conductive type semiconductor layer 123 after the semiconductor light emitting device is assembled into the display panel.

A portion of the first conductive semiconductor layer 121 is exposed, and a first electrode 155 may be disposed on the exposed upper surface. The first conductive semiconductor layer 121 can receive power through the first electrode 155. Additionally, a second electrode 153 may be disposed on the transparent electrode layer 124. The second electrode may be formed in a donut shape surrounding the edge of the transparent electrode layer 124. The second conductive semiconductor layer 123 can receive power through the second electrode 153.

A reflective insulating layer 130 may be disposed on the side of the light emitting structure 120. The reflective insulating layer 130 may be formed including oxide. The reflective insulating layer can be formed by layering materials with different refractive indices and can have the property of reflecting light. The reflective insulating layer 130 may be formed by stacking TiO ₂ /SiO ₂ in multiple layers, but is not limited thereto. Additionally, an insulating layer 140 may be disposed on the reflective insulating layer 130.

Meanwhile, in the conventional technology, a single oxide layer deposited through a CVD process was used as the passivation layer covering the light emitting structure. However, the single-layer oxide layer has poor film quality and pinholes exist.

In particular, semiconductor light emitting devices used for displays must be protected because they are assembled on a panel substrate and the display process continues even after the chip is manufactured. However, the passivation layer is damaged by the display process, and as a result, a chemical solution, etc. penetrates the semiconductor layer through pin holes, causing damage, which may cause a problem in which the light does not turn on.

Accordingly, in order to solve the above problem, the embodiment forms a reflective insulating layer on the side of the light emitting structure 120 to prevent penetration of chemical solutions, etc. when the display process proceeds after the semiconductor light emitting device is assembled on the panel substrate. There is a technical effect of preventing damage to the semiconductor layer by increasing resistance to the etching process.

In addition, the reflective insulating layer 130 has the technical effect of effectively blocking leakage current compared to a single layer as the oxide layer is deposited in layers.

In addition, the reflective insulating layer 130 can reflect light generated from the light emitting structure 120 that escapes from the side back into the light emitting structure and allow it to escape upward. Accordingly, the semiconductor light emitting device for pixels according to the embodiment has the technical effect of improving luminance in the upward direction as the reflective insulating layer 130 disposed on the side of the light emitting structure is used as a reflective layer.

Figure 3 is a cross-sectional view of a semiconductor light emitting device for a pixel according to a second embodiment. The semiconductor light emitting device for pixels according to the second embodiment can adopt the technical features of the first embodiment. For example, the reflective insulating layer 130 formed of multiple layers can improve light extraction efficiency through total internal reflection of light, and has the technical effect of preventing chip damage by preventing penetration of chemical solutions.

Meanwhile, in the second embodiment, a current blocking layer (CBL) may be formed under the active layer. The current blocking layer 126 can minimize current that may leak to the side. In addition, current can be prevented from entering the active area under the upper electrode, and since the injected current is refracted and flows, there is a technical effect that light extraction efficiency can be improved.

Additionally, a reflective layer 125 may be formed between the first conductive semiconductor layer 121 and the current blocking layer 126. The reflective layer 125 may be formed of a DBR layer using metal or oxide, and has the technical effect of improving light efficiency by reflecting light emitted downward from the active layer 122 upward.

Figure 4 is a cross-sectional view of a semiconductor light emitting device for a pixel according to a third embodiment. The semiconductor light emitting device for pixels according to the fourth embodiment can adopt the technical features of the first and second embodiments. For example, through the reflective insulating layer 130 formed in multiple layers, light extraction efficiency can be improved through total internal reflection of light, and there is a technical effect of preventing chip damage by preventing penetration of chemical solutions.

Referring to FIG. 4, the semiconductor light emitting device for a pixel according to the third embodiment may be a vertical semiconductor light emitting device. The light emitting structure 120 is interposed between the first conductive semiconductor layer 121 and the second conductive semiconductor layer 123 and the first conductive semiconductor layer 121 and the second conductive semiconductor layer 123. It may include an active layer 122. Additionally, a transparent electrode layer 124 may be disposed on the light emitting structure 120. The transparent electrode layer 124 includes a light-transmitting material and may be formed of ITO (Indium Tin Oxide), but is not limited thereto. The transparent electrode layer 124 may then serve to supply power from the display panel wiring to the second conductive semiconductor layer 123.

Additionally, a third electrode 128 may be disposed below the light emitting structure 120. The third electrode 128 may later serve to supply power from the display panel wiring to the first conductive semiconductor layer 121.

The reflective insulating layer 130 has the technical effect of protecting the semiconductor light emitting device by preventing penetration of a chemical solution when the semiconductor light emitting device 150 is assembled into the display panel and the process is performed at the panel end.

5A to 5D are diagrams showing the manufacturing process of a semiconductor light emitting device for a pixel according to the first embodiment.

Referring to FIG. 5A, the light emitting structure 120 is formed on the substrate 110. The light emitting structure 120 is interposed between the first conductive semiconductor layer 121 and the second conductive semiconductor layer 123 and the first conductive semiconductor layer 121 and the second conductive semiconductor layer 123. It may include an active layer 122. Additionally, a transparent electrode layer 124 may be disposed on the light emitting structure 120. The transparent electrode layer 124 may be formed of ITO (Indium Tin Oxide), but is not limited thereto.

Next, referring to FIG. 5B, an etching process may be performed to form the side of the light emitting structure 120 to be inclined. For example, mesa etching may be performed. At this time, a portion of the first conductivity type semiconductor layer 121 may be formed so that the upper surface of the first conductivity type semiconductor layer 121 is exposed without being etched.

Referring to FIG. 5C, a reflective insulating layer 130 may be formed to cover the light emitting structure 120 and the transparent electrode layer 124. The reflective insulating layer 130 may be formed by alternately stacking TiO ₂ /SiO ₂ , but is not limited thereto.

The reflective insulating layer 130 may be a DBR layer formed of materials with different refractive indices. Accordingly, the reflective insulating layer 130 can perform the role of a reflective layer, and has the technical effect of improving light efficiency by reflecting light exiting from the side from the active layer 122 upward.

In addition, the reflective insulating layer 130 formed by stacking several layers has a technical effect of preventing defect issues due to pin holes formed throughout the oxide layer, compared to a conventional passivation layer formed as a single layer.

For example, after a semiconductor light emitting device is assembled into a display panel, when a display process such as etching, photo, or deposition is performed, it is possible to prevent problems such as chemical solutions penetrating into pin holes and damaging the light emitting structure. In detail, the reflective insulating layer 130 is made by alternately stacking two layers containing oxide, so that pin holes between layers are not connected, thereby preventing penetration of chemical solutions and increasing resistance to the etching process to prevent damage to the chip. There is a special technical effect that can prevent.

Next, referring to FIG. 5D, the reflective insulating layer 130 can be etched to form a portion of the transparent electrode layer 124 through which light is emitted from the semiconductor light emitting device and an electrode electrically connected to the semiconductor light emitting device. there is. The reflective insulating layer 130 may be etched so that a portion of the upper surface of the first conductive semiconductor layer 121 is exposed.

Then, an insulating layer 140 is formed to cover the reflective insulating layer 130. The insulating layer 140 may also cover the transparent electrode layer 124 and the first conductive semiconductor layer 121 exposed by etching the reflective insulating layer 130. The insulating layer 140 may not be formed in an area that horizontally overlaps the substrate 110 .

Subsequently, a portion of the insulating layer 140 formed on the transparent electrode layer 124 may be etched and a second electrode 153 may be formed so that the transparent electrode layer 124 can receive power.

In addition, a portion of the insulating layer 140 and the reflective insulating layer 130 formed on the first conductive semiconductor layer 121 are etched and the first conductive semiconductor layer 121 is etched so that the first conductive semiconductor layer 121 can receive power. 1 electrode 155 can be formed.

Figure 6 is a conceptual diagram of a display device including a semiconductor light-emitting device for a pixel according to a fourth embodiment. Referring to FIG. 6 , in the fourth embodiment, a plurality of assembly wirings 160 may be disposed on the assembly substrate 115 . The plurality of assembly wires 160 may include first assembly wires 160a and second assembly wires 160b arranged to be spaced apart from each other. Different power sources are applied to the first assembly wiring 160a and the second assembly wiring 160b through alternating current, and a DEP force can be formed to enable the semiconductor light emitting device 150 to be assembled in the assembly hole.

Additionally, an insulating film 162 may be disposed on the plurality of assembly wirings 160, and a partition wall 165 having an assembly hole may be disposed on the insulating film 162. A semiconductor light emitting device 150 may be placed in the assembly hole. The semiconductor light emitting device 150 may be a semiconductor light emitting device for pixels of the first to third embodiments.

The semiconductor light emitting device 150 includes a light emitting structure 120 and may include a reflective insulating layer 130 disposed on a side of the light emitting structure 120. The reflective insulating layer 130 includes oxide materials having different refractive indices and may be a DBR layer in which the two materials are alternately deposited and stacked. For example, it may be formed by alternately stacking TiO ₂ /SiO ₂ materials, but the present invention is not limited thereto.

The reflective insulating layer 130 is formed of a DBR layer and has the technical effect of improving light efficiency by reflecting light exiting from the side of the light emitting structure upward. In addition, since the oxide material is formed in alternating layers rather than a single layer, the pin holes are not connected between layers, so chemical solutions or gases cannot penetrate into the pin holes during the display process, which has the technical effect of protecting the light emitting structure. Therefore, there is a technical effect that can prevent lighting defect issues in semiconductor light emitting devices.

Subsequently, an insulating layer 140 may be disposed on the reflective insulating layer 130. Additionally, the semiconductor light emitting device 150 can function as a pixel by receiving power from the panel electrode.

The semiconductor light emitting device for pixels according to the embodiment and the display device including the same have a technical effect of improving luminance.

Additionally, the embodiment has a technical effect that can improve light output.

For example, in an embodiment, the DBR layer is made of materials with different refractive indices so that light that escapes from the bottom and sides of the chip can be reflected upward.

Additionally, the embodiment has the technical effect of protecting the LED chip during the display panel process after assembling the LED chip into the panel.

Additionally, the embodiment has the technical effect of blocking leakage current.

For example, in the embodiment, the passivation layer is formed of a plurality of layers, and a current blocking layer can be formed to block leakage current.

Additionally, the embodiment has the technical effect of preventing damage to the LED chip by penetrating the chemical solution through the pinhole.

For example, in the embodiment, the passivation layer is formed by alternately depositing a plurality of layers, so that pin holes are not connected between layers, so chemical solutions or gases cannot penetrate.

Additionally, the embodiment has the technical effect of preventing lighting defects in the LED chip.

For example, the embodiment can prevent lighting defects in LED chips because the issue of damage to the light emitting structure is significantly reduced even if the panel process progresses.

10, 110, 115: substrate
20, 120: Light-emitting structure
40: Passivation layer
45: pin hole
121: First conductive semiconductor layer
122: active layer
123: Second conductive semiconductor layer
124: Transparent electrode layer
128: third electrode
130: reflective insulating layer
140: insulation layer
150: Semiconductor light emitting device
153: second electrode
155: first electrode
160: assembly wiring
160a: first assembly wiring
160b: second assembly wiring
162: insulating film
165: Bulkhead
167: panel electrode
170: insulating layer

Claims (10)

A light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer;
a reflective insulating layer surrounding a portion of the light emitting structure; and
It includes an insulating layer disposed on the reflective insulating layer,
A semiconductor light emitting device for a pixel, wherein the reflective insulating layer is arranged by stacking a plurality of layers. According to paragraph 1,
A semiconductor light emitting device for a pixel, wherein the insulating layer exposes a portion of the reflective insulating layer. According to paragraph 1,
A semiconductor light emitting device for a pixel, further comprising a current blocking layer disposed below the active layer and blocking current flowing out of the active layer laterally. According to paragraph 1,
A semiconductor light emitting device for a pixel, further comprising a reflective layer disposed below the active layer. According to paragraph 1,
A semiconductor light emitting device for a pixel, wherein the reflective insulating layer includes an oxide material. According to clause 5,
A semiconductor light emitting device for a pixel, wherein the reflective insulating layer is formed by alternately stacking TiO ₂ /SiO ₂ . According to paragraph 1,
A semiconductor light emitting device for a pixel, wherein the reflective insulating layer covers a side of the light emitting structure. According to paragraph 1,
The reflective insulating layer is arranged to extend from a side of the first conductive semiconductor layer to the second conductive semiconductor layer. According to paragraph 1,
A semiconductor light emitting device for a pixel, wherein the reflective insulating layer includes materials having different refractive indices. A board having a plurality of assembly wirings;
a partition disposed on the substrate and having an assembly hole;
A display device comprising a semiconductor light-emitting device, including the semiconductor light-emitting device for a pixel according to any one of claims 1 to 9 disposed in the assembly hole.

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