WO2024117311A1

WO2024117311A1 - Laminated semiconductor light-emitting element for display pixel, and display device comprising same

Info

Publication number: WO2024117311A1
Application number: PCT/KR2022/019288
Authority: WO
Inventors: 남정범; 장영학; 방형석; 장성규
Original assignee: 엘지전자 주식회사
Priority date: 2022-11-30
Filing date: 2022-11-30
Publication date: 2024-06-06

Abstract

This laminated semiconductor light-emitting element for a display pixel according to an embodiment may comprise: a substrate; a plurality of semiconductor light-emitting elements vertically disposed on the substrate; a common electrode and an individual electrode that are electrically connected to the plurality of semiconductor light-emitting elements; a transparent conductive layer that is in contact with one surface of each of the plurality of semiconductor light-emitting elements and connected to the individual electrode; and an optical conversion layer arranged on the lower surface of the transparent conductive layer.

Description

Stacked semiconductor light emitting device for display pixels and display device including the same

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

Smart glasses for AR or VR require high-resolution and high ppi displays. However, in the case of planar RGB light emitting devices, when one color emits light, the area of the color that does not emit light appears empty, making it difficult to implement high ppi.

Therefore, there is research on a high ppi display device through a structure in which RGB semiconductor light emitting devices are vertically stacked on a substrate, and micro-LEDs, etc. can be used as semiconductor light emitting devices.

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 reproduction rate, 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 the case of small display devices such as smart glasses, it is difficult to form vias in each RGB semiconductor light emitting device in a stacked semiconductor light emitting device using ultra-small micro-LEDs, making it difficult to supply power, and the problem is solved through the present invention. I want to solve it.

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

Another object of the embodiment is to provide a stacked semiconductor light-emitting device for display pixels capable of implementing a high ppi and high-resolution display, and a display device including the same.

Additionally, another purpose of the embodiment is to provide a stacked semiconductor light emitting device for display pixels that can increase light efficiency through light scattering and a display device including the same.

Additionally, another purpose of the embodiment is to provide a stacked semiconductor light emitting device for display pixels that can improve the speed of electrical signal transmission and a display device including the same.

In addition, another object of the embodiment is to provide a stacked semiconductor light emitting device for a display pixel capable of forming a via hole outside the semiconductor epi layer and a display device including the same.

Another object of the embodiment is to provide a stacked semiconductor light emitting device for display pixels capable of improving light extraction in the vertical direction and a display device including the same.

Another object of the embodiment is to provide a stacked semiconductor light emitting device for display pixels that can minimize loss of the light emitting area and a display device including the same.

The technical problems of the embodiments are not limited to those described in this item and include those that can be understood throughout the specification.

A stacked semiconductor light emitting device for display pixels according to an embodiment includes a substrate; first, second and third semiconductor light emitting devices arranged vertically on the substrate; a common electrode electrically connected to the first, second, and third semiconductor light emitting devices; disposed on one side of each of the first, second, and third semiconductor light emitting devices to be spaced apart from each other in the vertical direction; A first electrode, a second electrode, and a third electrode electrically connected; It includes first, second and third transparent conductive layers respectively in contact with one surface of the first, second and third semiconductor light emitting devices and connected to the first electrode, second electrode and third electrode respectively,

The first, second and third transparent conductive layers include regions that overlap with the first, second and third semiconductor light emitting devices and regions that do not overlap with the first, second and third semiconductor light emitting devices, It may include first, second, and third light conversion layers respectively disposed on lower surfaces of the first, second, and third transparent conductive layers.

Additionally, in an embodiment, the first transparent conductive layer extends horizontally from one surface of the first semiconductor light emitting device and is connected to the first electrode,

The second transparent conductive layer extends horizontally from one surface of the second semiconductor light emitting device and is connected to the second electrode,

The third transparent conductive layer may extend horizontally from one surface of the third semiconductor light emitting device and be connected to the third electrode.

Additionally, in an embodiment, the first transparent conductive layer may have a larger area than the first semiconductor light emitting device.

Additionally, in an embodiment, the common electrode and the first, second, and third electrodes may surround the semiconductor light emitting device.

Additionally, in an embodiment, the first light conversion layer may include a light reflection layer.

Additionally, in an embodiment, the second and third light conversion layers may include a light scattering layer.

Additionally, in an embodiment, the first, second, and third light conversion layers may include nanowires containing Ag.

Additionally, in the embodiment, the common electrode includes a fourth electrode connected to the first, second, and third semiconductor light emitting devices,

The fourth electrode may be disposed on at least a portion of the other surface of the first, second, and third semiconductor light emitting devices.

Additionally, in an embodiment, each of the first, second, and third electrodes may have different heights.

Additionally, in an embodiment, it may further include a passivation layer disposed on the substrate and covering the first, second, and third semiconductor light emitting devices, the common electrode, and the first, second, and third electrodes.

According to the stacked semiconductor light emitting device for display pixels according to the embodiment and the display device including the same, there is a technical effect of realizing high resolution and high ppi by forming it in a stacked structure.

Additionally, the embodiment has the technical effect of enabling electrical connection without loss of the light-emitting area of the semiconductor light-emitting device.

For example, a semiconductor light-emitting device can receive electrical signals by being connected to an individual electrode through a transparent conductive layer disposed on the bottom of the semiconductor light-emitting device, and there is no need to form a via for electrical connection in the semiconductor light-emitting device, so the light-emitting area is There is a technical effect of increasing luminous efficiency because there is no loss.

In addition, the transparent conductive layer 150 is disposed in the area overlapping the semiconductor light emitting device 130 to improve the efficiency of light emitted upward from the stacked semiconductor light emitting device.

Additionally, the embodiment has the technical effect of improving light efficiency through light scattering.

For example, light efficiency can be improved by placing a light conversion layer under the transparent conductive layer.

Additionally, the embodiment has the technical effect of improving the speed of electrical signal transmission.

For example, the light conversion layer disposed below the transparent conductive layer has higher electrical conductivity than the transparent conductive layer, so the signal transmission speed from the electrode to the semiconductor light emitting device can be improved.

Additionally, the embodiment has the technical effect of improving light efficiency through light reflection.

For example, a light reflection layer is disposed below the transparent conductive layer connected to the bottommost semiconductor light emitting device in the stacked structure, so that light emitted from the bottom of the stacked structure is reflected upward to improve light efficiency.

In addition, the embodiment has the technical effect of lowering the difficulty of the process by eliminating the need to form via holes in the semiconductor epitaxial layer.

In addition, the embodiment provides a technical effect in which the electrode connected to the semiconductor light-emitting device is disposed outside the light-emitting area, thereby improving light output, and is arranged to surround the semiconductor light-emitting device on the substrate, thereby securing a sufficient light-emitting area to improve luminance. There is.

In addition, in the embodiment, the electrode layer disposed in the area that does not overlap with the semiconductor light emitting device 130 also has a transparent conductive layer 150 to prevent reverse reflection of light emitted upward from the stacked semiconductor light emitting device, thereby significantly improving luminance. There are special technical effects that can be achieved.

The technical effects of the embodiments are not limited to those described in this item and include those that can be understood throughout the specification.

1 is a perspective view of a stacked semiconductor light emitting device for display pixels according to an embodiment.

Figure 2 is a conceptual diagram of a stacked semiconductor light emitting device for display pixels according to an embodiment.

Figure 3 is a cross-sectional view showing in detail the structure of the semiconductor light emitting device shown in Figure 2.

4A to 4G are process diagrams of a stacked semiconductor light emitting device for display pixels according to an embodiment.

Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. 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.

Semiconductor light emitting devices described in this specification include smart glasses, digital TVs, mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), and navigation devices. , Slate PC, Tablet PC, Ultra-Book, desktop computer, etc. may be included. 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.

Hereinafter, a stacked semiconductor light-emitting device for display pixels including a semiconductor light-emitting device according to an embodiment will be described.

Figure 1 is a perspective view of a stacked semiconductor light emitting device for display pixels (hereinafter referred to as 'stacked semiconductor light emitting device') according to an embodiment. In the embodiment, the semiconductor light emitting device may be a micro-LED or nano-LED, but is not limited thereto.

Referring to FIG. 1, a semiconductor light emitting device 130 may be disposed on a substrate 110. The semiconductor light emitting device 130 may include first, second, and third semiconductor

light emitting devices

131, 132, and 133, and may be formed in a cylindrical shape, but is not limited thereto. The first, second, and third semiconductor

light emitting devices

131, 132, and 133 may be vertically stacked. Additionally, the common electrode 120, the first electrode 125a, the second electrode 125b, and the third electrode 125c (not shown) may be disposed on the substrate 110. Additionally, the substrate 110 may include CMOS to drive a semiconductor light emitting device, and may be made of silicon or the like.

The semiconductor light emitting device 130 may be electrically connected to the common electrode 120. The common electrode 120 may commonly supply power to the first to third semiconductor

light emitting devices

131, 132, and 133. The first semiconductor light emitting device 131 may be electrically connected to the first electrode 125a. The second semiconductor light emitting device 132 may be electrically connected to the second electrode 125b. The third semiconductor light emitting device 133 may be electrically connected to the third electrode 125c (see FIG. 2). The common electrode 120 and the first, second, and

third electrodes

125a, 125b, and 125c are electrically connected to the CMOS provided in the substrate 110 to drive semiconductor light emitting devices.

An insulating layer 140 may be disposed under the first, second, and third semiconductor

light emitting devices

131, 132, and 133. The insulating layer may be formed of SiO ₂ , but is not limited thereto. The insulating layer 140 prevents electrical short circuits in each semiconductor light emitting device, and has adhesive strength to stabilize the stacked structure. In addition, there is a technical effect of absorbing heat generated from the semiconductor light-emitting device 130 and performing the heat dissipation function of the semiconductor light-emitting device 130.

Meanwhile, according to internal research on stacked semiconductor light emitting devices, existing stacked semiconductor light emitting devices vertically stack light emitting devices that emit R, G, and B colors, and then form vias in the epi layer of each light emitting device to electrically connect them. I ordered it.

However, in display devices that require high ppi and high resolution, such as VR, AR, and MR, ultra-small semiconductor light emitting devices are used, and in the case of ultra-small micro-LEDs, the size is so small that it is difficult to form a via in the epi layer. In addition, because the material of the epi layer was different depending on the color of the light emitting, the etching conditions were different, making it difficult to form via holes. Therefore, there is a need to research electrical connection methods other than electrical connection through via holes in stacked semiconductor light emitting devices.

Referring again to FIG. 1, the first, second, and

third electrodes

125a, 125b, and 125c are connected to the first, second, and second electrodes through the first, second, and third transparent

conductive layers

150a, 150b, and 150c. , may be electrically connected to the third semiconductor light emitting device (131, 132, 133).

The stacked semiconductor light-emitting device 130 for display pixels according to an embodiment is a semiconductor light-emitting device ( 130) and the substrate are electrically connected, there is no need to form a via hole, so there is no loss of area of the epi layer, and there is a complex technical effect of improving the reliability of the epi layer because the via process is not performed on the epi layer.

In an embodiment, the transparent conductive layer 150 may include an area that overlaps the semiconductor light-emitting device 130 and an area that extends outside the semiconductor light-emitting device 130 and does not overlap the semiconductor light-emitting device 130.

Accordingly, according to the embodiment, high resolution and high ppi are realized by forming a stacked structure, and at the same time, unlike the prior art, the lower electrode layer is placed on the outside so as not to overlap the semiconductor light emitting device 130, thereby enabling electrical connection without loss of the light emitting area. There is a technical effect that makes it possible.

Additionally, in the embodiment, the transparent conductive layer 150 is disposed in the area overlapping the semiconductor light emitting device 130 to improve the efficiency of light emitted upward from the stacked semiconductor light emitting device.

In addition, in the embodiment, unlike the prior art, the transparent conductive layer 150 is disposed on the electrode layer disposed in an area that does not overlap the semiconductor light emitting device 130 to prevent reverse reflection of light emitted upward from the stacked semiconductor light emitting device, thereby increasing the luminance. There is a special technical effect that can significantly improve.

Meanwhile, a light conversion layer 160 may be disposed on the lower surface of the transparent conductive layer 150. The light conversion layer 160 may include a first light conversion layer 161, a second light conversion layer 162, and a third light conversion layer 163, and each includes a first transparent conductive layer 150a. , electrically connected to the first semiconductor light-emitting device 131, the second semiconductor light-emitting device 132, and the third semiconductor light-emitting device 133 through the second transparent conductive layer 150b and the third transparent conductive layer 150c. You can.

The light conversion layer 160 may be formed in a nanowire structure. The light conversion layer 160 may have lower electrical resistance than the transparent conductive layer 150. This will be explained in detail in Figure 4a.

Meanwhile, the embodiment has a technical feature in that optical characteristics vary depending on the content of Ag nanowires in the light conversion layer 160. In detail, if the content of Ag nanowires is small, light transmittance can increase and light scattering rate can increase. Additionally, as the content of Ag nanowires increases, light transmittance may decrease and light reflectance may increase. Therefore, in the embodiment, the light conversion layer 160 can obtain specific optical characteristics by adjusting the content of Ag nanowires.

Additionally, when power is supplied from the first, second, and

third electrodes

125a, 125b, and 125c to the semiconductor light emitting device, the power may be supplied through the light conversion layer 160. Therefore, the stacked semiconductor light emitting device for display pixels according to the embodiment and the display device including the same have the technical effect of improving the speed of electrical signal transmission through the light conversion layer.

Additionally, the common electrode 120 and the first, second, and

third electrodes

125a, 125b, and 125c may be arranged to surround the semiconductor light emitting device 130. Accordingly, there is a technical effect of maximizing the light emitting area of the semiconductor light emitting device disposed on the substrate 110. Additionally, there is a technical effect of minimizing electrical interference between electrodes.

Additionally, the transparent conductive layer 150 may be formed of, for example, indium tin oxide (ITO). Since the conductive layer through which light emitted from the bottom of the semiconductor light emitting device of the stacked structure passes is transparent and has transparency, there is a technical effect of increasing the light traveling upward.

Meanwhile, the first light conversion layer 161 may have a higher Ag nanowire content than the second and third light conversion layers 162 and 163. The first light conversion layer 161, which has a large content of Ag nanowires, may have low light transmittance and high light reflectance. Additionally, the second and third light conversion layers 162 and 163, which contain a small amount of Ag nanowires, may have high light transmittance and high light scattering rate.

The second light conversion layer 162 and the third light conversion layer 163 disposed on the lower surfaces of the second transparent conductive layer 150b and the third transparent conductive layer 150c may be used as a light scattering layer. Accordingly, there is a technical effect that light efficiency can be improved in a display device including a semiconductor light emitting device with a stacked structure.

In detail, when light is extracted from the first semiconductor light emitting device 131, it may pass through the second light conversion layer 162 and be emitted upward. At this time, the emitted light is scattered by the second light conversion layer 162, and light efficiency can be improved.

Additionally, when light is extracted from the first and second semiconductor

light emitting devices

131 and 132, it may pass through the third light conversion layer 163 and head upward. Light is scattered by the third light conversion layer 163, and light efficiency can be improved. Accordingly, the embodiment has the technical effect of improving light efficiency as the second and third light conversion layers 162 and 163 are used as light scattering layers.

Additionally, the first light conversion layer 161 disposed on the lower surface of the first transparent conductive layer 161 may be used as a light reflection layer. In detail, when light is extracted from the first, second, and third semiconductor

light emitting devices

131, 132, and 133, the light directed downward may be reflected upward by the first light conversion layer 161. Accordingly, the embodiment has the technical effect of improving light extraction efficiency as the first light conversion layer 161 is used as a light reflection layer.

Meanwhile, the semiconductor light emitting device 130, the common electrode 120, and the first, second, and

third electrodes

125a, 125b, and 125c disposed on the substrate may be surrounded by the passivation layer 140. The passivation layer 140 can protect the semiconductor light emitting device 130, the common electrode 120, and the first, second, and

third electrodes

125a, 125b, and 125c from external shock and prevents electrical shorts from occurring. You can avoid it. The passivation layer 140 may be formed of SiO ₂ , but is not limited thereto.

Figure 2 is a conceptual diagram of a stacked semiconductor light emitting device according to an embodiment.

Referring to FIG. 2 , a stacked semiconductor light emitting device 130 including first to third semiconductor

light emitting devices

131 , 132 , and 133 may be disposed on the substrate 110 . Additionally, an individual electrode 125 and a common electrode 120 may be disposed on the substrate 110. The individual electrode 125 may include a first electrode 125a, a second electrode 125b, and a third electrode 125c. The semiconductor light emitting device 130 may be connected to the individual electrode 125 and the common electrode 120 through a transparent conductive layer 150.

The transparent conductive layer 150 may include a first transparent conductive layer 150a, a second transparent conductive layer 150b, and a third transparent conductive layer 150c.

The first semiconductor light emitting device 131 may be electrically connected to the first electrode 125a through the first transparent conductive layer 150a. The second semiconductor light emitting device 132 may be electrically connected to the second electrode 125b through the second transparent conductive layer 150b. The third semiconductor light emitting device 133 may be electrically connected to the third electrode 125c through the third transparent conductive layer 150c.

Additionally, a light conversion layer 160 may be disposed on the lower surface of the transparent conductive layer 150. A first light conversion layer 161 is disposed on the lower surface of the first transparent conductive layer 150a, a second light conversion layer 162 is disposed on the lower surface of the second transparent conductive layer 150b, and a third transparent conductive layer is disposed on the lower surface of the first transparent conductive layer 150a. A third light conversion layer 163 may be disposed on the lower surface of the layer 150c.

The light conversion layer 160 may be formed to have lower resistance than the transparent conductive layer 150. For example, the light conversion layer 160 may be formed of nanowires or Ag, but is not limited thereto.

Meanwhile, the first semiconductor light-emitting device 131 emits a red color, the second semiconductor light-emitting device 132 emits a green color, and the third semiconductor light-emitting device 133 is a semiconductor light-emitting device that emits a blue color. It may be possible, but it is not limited to this.

At this time, the first, second, and

third electrodes

125a, 125b, and 125c may each be formed at different heights. The transparent conductive layer 150 is formed of a light-transmitting material to minimize light loss when light generated from the semiconductor light emitting device located below is directed upward, and is connected to the first, second, and

third electrodes

125a and 125b. , 125c) and the first, second, and third semiconductor

light emitting devices

131, 132, and 133 have the technical effect of being able to electrically connect them.

And, in the embodiment, the fourth electrode 121 may be formed on a portion of the upper surface of the semiconductor light emitting device 130 to correspond to the shape of the upper surface. For example, when the semiconductor light emitting device 130 has a cylindrical shape, the fourth electrode 121 may have a ring shape.

The fourth electrode 121 includes 4-1 to 4-3

electrodes

121a, 121b, and 121c that are electrically connected to the first, second, and third semiconductor

light emitting devices

131, 132, and 133, respectively. ) may include.

For example, the first semiconductor light emitting device 131 may be electrically connected to the common electrode 120 through the 4-1 electrode 121a, and the second semiconductor light emitting device 132 may be electrically connected to the 4-2 electrode ( It can be electrically connected to the common electrode 120 through 121b), and the third semiconductor light emitting device 133 can be electrically connected to the common electrode 120 through the 4-3 electrode 121c.

Next, Figure 3 is a diagram showing the semiconductor light emitting device in detail in the stacked semiconductor light emitting device for display pixels according to an embodiment. The following description can be applied to the first, second, and third semiconductor

light emitting devices

131, 132, and 133.

Referring to FIG. 3, the semiconductor light emitting device 130 may include a first conductivity type semiconductor layer 136, a second conductivity type semiconductor layer 138, and an active layer 137 disposed between them. The first conductive semiconductor layer 136 may be an n-type semiconductor layer, and the second conductive semiconductor layer 138 may be a p-type semiconductor layer, but are not limited thereto.

The active layer 137 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 137. Therefore, depending on the energy band gap of the compound semiconductor included in the active layer 157, the semiconductor light emitting device 130 of the embodiment can generate UV light, blue light, green light, and red light.

The first conductive semiconductor layer 156, the active layer 157, and the second conductive semiconductor layer 158 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.

Additionally, the first electrode layer 134 may be disposed under the first conductive semiconductor layer 136, and the second electrode layer 139 may be disposed on the second conductive semiconductor layer 138. The first electrode layer 134 is electrically connected to one of the first, second, and third electrodes through the transparent conductive layer 150 and the light conversion layer 160, and the second electrode layer 139 is a common electrode ( 120) and can be electrically connected.

4A to 4G are manufacturing process diagrams of a stacked semiconductor light emitting device for display pixels according to an embodiment.

Referring to FIG. 4A, the epitaxial layer 135 may be grown on the growth substrate 115. The epitaxial layer 135 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.

A transparent conductive layer 150 may be formed on the epi layer. The transparent conductive layer 150 is made of a light-transmissive material and may have electrical conductivity. The transparent conductive layer 150 may be formed of, for example, ITO (Indum Tin Oxide), but is not limited thereto.

Subsequently, the light conversion layer 160 may be formed on the light-transmitting conductive layer 150. In detail, a dispersion containing Ag can be applied on the light-transmitting conductive layer 150 by spin coating, and then soft baking can be performed. The dispersion may contain nanoscale Ag wires. Then, when photonic welding is performed on the light-transmitting conductive layer 150 at about 300°C, it is attached to the light-transmitting conductive layer and can be formed in the form of a nano-sized wire. The formed light conversion layer may have superior current diffusion characteristics compared to the transparent conductive layer.

Meanwhile, the light conversion layer 160 formed on the light-transmitting conductive layer 150 can be formed by varying the content of Ag nanowires. The light conversion layer 160 may have different optical characteristics depending on the content of Ag nanowires. In detail, if the content of Ag nanowires is small, light transmittance can increase and light scattering rate can increase. Additionally, as the content of Ag nanowires increases, light transmittance may decrease and light reflectance may increase. Therefore, the light conversion layer 160 can obtain specific optical characteristics by adjusting the content of Ag nanowires.

Accordingly, the embodiment has the technical effect of improving the speed of electrical signal transmission to the semiconductor light-emitting device by forming the light conversion layer in the form of nanowires containing Ag. In addition, there is a complex technical effect in which light efficiency can be improved by directing the light generated from the semiconductor light emitting device upward.

Next, referring to FIG. 4B, the 1-1 insulating layer 140a may be disposed under the light conversion layer 160. Then, the 1-2 insulating layer 140b can be formed and prepared on the substrate 110 on which the CMOS is formed. The 1-1 insulating layer 140a disposed below the light conversion layer 160 may be bonded so that the 1-2 insulating layer 140b disposed on the substrate 110 faces each other. The 1-1 and 1-2 insulating layers 140a and 140b may be SiO ₂ , but are not limited thereto. SiO ₂ andBonding of SiO ₂ originally requires a high temperature process of about 700°C, but the surfaces of the 1-1 and 1-2 insulating layers 140a1 and 140b can be plasma treated, and thus, at a temperature of about 400°C. The bonding process can be performed so that the epitaxial layer 135 is not damaged by high temperature.

Referring to FIG. 4C, a process of removing the growth substrate 115 is then performed. In the case of a semiconductor light emitting device that emits blue or green color, the epi layer 135 may be formed of GaN, etc., and the growth substrate may be removed through a laser lift-off (LLO) method, but is not limited to this. In the case of a semiconductor light emitting device that emits red color, the epitaxial layer 135 may be formed of GaAs, etc., and the growth substrate may be removed through a chemical lift-off (CLO) method, but is not limited to this.

Referring to FIG. 4D, a hard mask (not shown) can be deposited on the epi layer 135 and a photo process and an etching process can be performed. The transparent conductive layer 150 may be formed in an oval shape.

Referring to FIG. 4E, a hard mask (not shown) can be deposited on the epi layer 135 and a photo process and an etching process can be performed. The epitaxial layer 135 may be etched into an oval shape. The epi layer may be formed to have a smaller area than the transparent conductive layer 150. Next, the exposed transparent conductive layer 150 and epi layer 135 are covered with an insulating layer. And, it can be flattened through the CMP process.

Referring to FIG. 4F, a first via hole is formed from the surface of the insulating layer 140 through the transparent conductive layer 150 to the surface of the substrate 110, and a semiconductor light emitting device 135 is formed on the surface of the insulating layer. A second via hole may be formed up to the top surface of the substrate so as not to overlap the transparent conductive layer 150.

An individual electrode 125 may be formed in the first via hole. The individual electrode 125 may be electrically connected to the semiconductor light emitting device 135 through the transparent conductive layer 150. Additionally, the individual electrode 125 may be electrically connected to the semiconductor light emitting device 135 through the light conversion layer 160 disposed on the lower surface of the transparent conductive layer 150.

The light conversion layer 160 may be formed in the form of an Ag nanowire, but is not limited to this. Accordingly, since the light conversion layer 160 may have a lower resistance than the transparent conductive layer 150, the speed of electrical signal transmission from the individual electrode 125 to the semiconductor light emitting device 135 will be improved. There are technical effects that can be achieved.

Subsequently, a common electrode 120 may be formed in the second via hole. The common electrode 120 may be electrically connected to the semiconductor light emitting device 135 and the fourth electrode 121. The fourth electrode may be formed at the edge of the upper surface of the semiconductor light emitting device 135, for example, in a ring shape, but is not limited to this.

The above manufacturing process can be repeated to manufacture a semiconductor light emitting device with a stacked structure as shown in FIG. 4g.

Referring to FIG. 4g, a second semiconductor light-emitting device 132 is disposed on the first semiconductor light-emitting device 131, and a third semiconductor light-emitting device 133 is disposed on the second semiconductor light-emitting device 132. You can.

The first semiconductor light emitting device 131 may be connected to the first electrode 125a through the first transparent conductive layer 150a. Additionally, a first light conversion layer 161 may be disposed on the lower surface of the first transparent conductive layer 150a.

The second semiconductor light emitting device 132 may be connected to the second electrode 125b through the second transparent conductive layer 150b. Additionally, a second light conversion layer 162 may be disposed on the lower surface of the second transparent conductive layer 150b.

The third semiconductor light emitting device 133 may be connected to the third electrode 125c through the third transparent conductive layer 150c. Additionally, a third light conversion layer 163 may be disposed on the lower surface of the third transparent conductive layer 150c.

At this time, the second light conversion layer 162 and the third light conversion layer 163 may be used as a light scattering layer. Accordingly, the second light conversion layer 162 can scatter the light emitted from the first semiconductor light emitting device 131 and increase the amount of light exiting the top. Additionally, the third light conversion layer 163 may scatter light emitted from the first and second semiconductor

light emitting devices

131 and 132 and increase the amount of light exiting the top.

Therefore, the embodiment has the technical effect of increasing light efficiency in a semiconductor light emitting device with a stacked structure as the light conversion layer disposed on the bottom of the transparent conductive layer is used as a light scattering layer.

Additionally, the first light conversion layer 161 may be used as a light reflection layer. The first light conversion layer 161 may reflect light emitted downward from the first semiconductor light emitting device 131 to increase the amount of light exiting upward. Therefore, the embodiment has the technical effect of increasing light efficiency in a semiconductor light emitting device with a stacked structure as the light conversion layer disposed on the lower surface of the transparent conductive layer is used as a light reflection layer. In particular, when the first semiconductor light emitting device 131 emits red color, luminous efficiency is low, but luminous efficiency can be improved to correspond to a semiconductor light emitting device that emits blue or green color through the light reflection layer.

For example, a semiconductor light emitting device can receive an electrical signal by being connected to an electrode through a transparent conductive layer disposed on the bottom, and there is no need to form a via for electrical connection in the semiconductor light emitting device, so there is no loss of the light emitting area and the light is emitted. There is a technical effect that can increase efficiency.

In addition, the embodiment provides a technical effect in which the electrode connected to the semiconductor light emitting device is disposed outside the light emitting area to improve light output, and the electrode is disposed to surround the semiconductor light emitting device on the substrate to sufficiently secure the light emitting area to improve luminance. There is.

The above detailed description should not be construed as restrictive in any respect and should be considered illustrative. The scope of the embodiments should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the embodiments are included in the scope of the embodiments.

[Explanation of symbols]

110: substrate

115: growth substrate

120: common electrode

121: fourth electrode

121a: 4-1 electrode

121b: 4-2 electrode

121c: 4-3 electrode

125a: first electrode

125b: second electrode

125c: third electrode

130: Semiconductor light emitting device

131: First semiconductor light emitting device

132: Second semiconductor light emitting device

133: Third semiconductor light emitting device

134: first electrode layer

135: epi layer

136: First conductive semiconductor layer

137: active layer

138: Second conductive semiconductor layer

139: second electrode layer

140: Passivation layer (insulating layer)

141a: 1-1 insulating layer

141b: 1-2 insulating layer

150: transparent conductive layer

150a: first transparent conductive layer

150b: second transparent conductive layer

160: Light conversion layer

161: first light conversion layer

162: second light conversion layer

163: Third light conversion layer

Claims

Board;

first, second and third semiconductor light emitting devices arranged vertically on the substrate;

A common electrode electrically connected to the first, second and third semiconductor light emitting devices,

a first electrode, a second electrode, and a third electrode arranged to be spaced apart from the first, second, and third semiconductor light emitting devices on one side so as not to overlap in the vertical direction, and electrically connected to each of the first, second, and third semiconductor light emitting devices;

It includes first, second and third transparent conductive layers respectively in contact with one surface of the first, second and third semiconductor light emitting devices and connected to the first electrode, second electrode and third electrode respectively,

The first, second and third transparent conductive layers include regions that overlap with the first, second and third semiconductor light emitting devices and regions that do not overlap with the first, second and third semiconductor light emitting devices,

A stacked semiconductor light emitting device for a display pixel, comprising first, second and third light conversion layers respectively disposed on lower surfaces of the first, second and third transparent conductive layers.
According to paragraph 1,

The first transparent conductive layer extends horizontally from one surface of the first semiconductor light emitting device and is connected to the first electrode,

The second transparent conductive layer extends horizontally from one surface of the second semiconductor light emitting device and is connected to the second electrode,

The third transparent conductive layer extends horizontally from one surface of the third semiconductor light emitting device and is connected to the third electrode.
According to paragraph 1,

A stacked semiconductor light emitting device for a display pixel, wherein the first transparent conductive layer has a larger area than the first semiconductor light emitting device.
According to paragraph 1,

A stacked semiconductor light emitting device for a display pixel, wherein the common electrode and the first, second, and third electrodes surround the semiconductor light emitting device.
According to paragraph 1,

A stacked semiconductor light emitting device for a display pixel, wherein the first light conversion layer includes a light reflection layer.
According to paragraph 1,

A stacked semiconductor light emitting device for a display pixel, wherein the second and third light conversion layers include a light scattering layer.
According to paragraph 1,

A stacked semiconductor light emitting device for a display pixel, wherein the first, second and third light conversion layers include nanowires containing Ag.
According to paragraph 1,

The common electrode includes a fourth electrode connected to the first, second and third semiconductor light emitting devices,

The fourth electrode is a stacked semiconductor light emitting device for a display pixel, wherein the fourth electrode is disposed on at least a portion of the other surface of the first, second, and third semiconductor light emitting devices.
According to paragraph 1,

A stacked semiconductor light emitting device for display pixels, wherein the first, second and third electrodes each have different heights.
According to paragraph 1,

A layered semiconductor for display pixels further comprising a passivation layer disposed on the substrate and covering the first, second, and third semiconductor light emitting elements, the common electrode, and the first, second, and third electrodes. Light emitting device.
In clause 7,

A stacked semiconductor light emitting device for a display pixel, wherein the first light conversion layer has a higher content of nanowires containing Ag than the second and third light conversion layers.