Laminated semiconductor light-emitting element for display pixel and display device including same

Abstract

A stacked semiconductor light emitting element for a display pixel according to an embodiment includes: a substrate; a plurality of semiconductor light emitting elements vertically disposed on the substrate; a common electrode and an independent electrode electrically connected to the plurality of semiconductor light-emitting elements; a transparent conductive layer which is in contact with one surface of each of the plurality of semiconductor light-emitting elements and is connected to the individual electrode; and a light conversion layer disposed on the lower surface of the transparent conductive layer.

Description

Technical Field

[0001] The embodiment relates to a stacked semiconductor light-emitting element for a display pixel and a display device including the stacked semiconductor light-emitting element. Background Art

[0002] Smart glasses for AR or VR are required to have a display with high resolution and high ppi (Pixels Per Inch). However, in the case of a planar RGB light-emitting element, when one color of light is emitted, the areas of the non-emitting colors appear hollow, and there is a problem in that it is difficult to achieve high ppi.

[0003] Therefore, a display device with high ppi has been studied by a structure in which RGB semiconductor light-emitting elements are vertically stacked on a substrate, and micro-LEDs (light-emitting diodes) or the like can be used for the semiconductor light-emitting elements.

[0004] A micro-LED display is a display that uses a semiconductor light-emitting element, i.e., a micro-LED, having a diameter or cross-sectional area of 100 μm or less as a display element.

[0005] Since a micro-LED display uses a semiconductor light-emitting element, i.e., a micro-LED, as a display element, it has excellent performance in many characteristics such as contrast ratio, response speed, color reproducibility, viewing angle, luminous intensity, resolution, lifespan, luminous efficiency, or brightness.

[0006] In particular, a micro-LED display can separate and combine images in a modular manner, and thus has the advantages of being able to freely adjust the size or resolution and being able to implement a flexible display.

[0007] On the contrary, in the case of a small display device such as smart glasses, it is difficult to form vias on each RGB semiconductor light-emitting element in a stacked semiconductor light-emitting element using ultra-small micro-LEDs, and thus there is a problem in that it is difficult to supply power. The present invention aims to solve such a problem. Summary of the Invention

[0008] Technical Problem

[0009] An object of the embodiment is to solve the above problems and other problems.

[0010] Another object of the embodiment is to provide a stacked semiconductor light-emitting element for a display pixel and a display device including the stacked semiconductor light-emitting element, which can implement a display with high ppi and high resolution.

[0011] In addition, another object of the embodiments is to provide a stacked semiconductor light-emitting element for a display pixel that can improve light efficiency through light scattering and a display device including the stacked semiconductor light-emitting element.

[0012] In addition, another object of the embodiments is to provide a stacked semiconductor light-emitting element for a display pixel that can improve the speed of electrical signal transmission and a display device including the stacked semiconductor light-emitting element.

[0013] In addition, another object of the embodiments is to provide a stacked semiconductor light-emitting element for a display pixel that can form a through hole outside the semiconductor epitaxial layer and a display device including the stacked semiconductor light-emitting element.

[0014] Another object of the embodiments is to provide a stacked semiconductor light-emitting element for a display pixel that can improve light extraction in the vertical direction and a display device including the stacked semiconductor light-emitting element.

[0015] Another object of the embodiments is to provide a stacked semiconductor light-emitting element for a display pixel that can minimize the loss of the light-emitting region and a display device including the stacked semiconductor light-emitting element.

[0016] The technical problems of the embodiments are not limited thereto, but include all problems that can be grasped through the entire specification.

[0017] Means for Solving the Technical Problems

[0018] The stacked semiconductor light-emitting element for a display pixel according to the embodiments includes: a substrate; a first semiconductor light-emitting element, a second semiconductor light-emitting element, and a third semiconductor light-emitting element, which are vertically arranged on the substrate; a common electrode electrically connected to the first semiconductor light-emitting element, the second semiconductor light-emitting element, and the third semiconductor light-emitting element; a first electrode, a second electrode, and a third electrode, which are arranged separately on one side of each semiconductor light-emitting element so as not to overlap with the first semiconductor light-emitting element, the second semiconductor light-emitting element, and the third semiconductor light-emitting element in the vertical direction and are electrically connected to each semiconductor light-emitting element respectively; and a first transparent conductive layer, a second transparent conductive layer, and a third transparent conductive layer, which are in contact with one surface of the first semiconductor light-emitting element, the second semiconductor light-emitting element, and the third semiconductor light-emitting element respectively and are connected to the first electrode, the second electrode, and the third electrode respectively.

[0019] The above-mentioned first transparent conductive layer, the above-mentioned second transparent conductive layer, and the above-mentioned third transparent conductive layer include regions overlapping with the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element, and regions not overlapping with the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element. The display pixel laminated semiconductor light-emitting element further includes: a first light conversion layer, a second light conversion layer, and a third light conversion layer, which are respectively disposed on the lower surfaces of the above-mentioned first transparent conductive layer, the above-mentioned second transparent conductive layer, and the above-mentioned third transparent conductive layer.

[0020] In addition, in the embodiment, the above-mentioned first transparent conductive layer extends horizontally along one surface of the above-mentioned first semiconductor light-emitting element and is connected to the above-mentioned first electrode, the above-mentioned second transparent conductive layer extends horizontally along one surface of the above-mentioned second semiconductor light-emitting element and is connected to the above-mentioned second electrode, and the above-mentioned third transparent conductive layer extends horizontally along one surface of the above-mentioned third semiconductor light-emitting element and is connected to the above-mentioned third electrode.

[0021] In addition, in the embodiment, the above-mentioned first transparent conductive layer has a larger area than the above-mentioned first semiconductor light-emitting element.

[0022] In addition, in the embodiment, the above-mentioned common electrode and the above-mentioned first electrode, the above-mentioned second electrode, and the above-mentioned third electrode surround the above-mentioned semiconductor light-emitting element.

[0023] In addition, in the embodiment, the above-mentioned first light conversion layer includes a light reflection layer.

[0024] In addition, in the embodiment, the above-mentioned second light conversion layer and the above-mentioned third light conversion layer include a light scattering layer.

[0025] In addition, in the embodiment, the above-mentioned first light conversion layer, the second light conversion layer, and the third light conversion layer include nanowires containing Ag.

[0026] In addition, in the embodiment, the above-mentioned common electrode includes a fourth electrode connected to the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element.

[0027] The above-mentioned fourth electrode is disposed on at least a part of the other surface of the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element.

[0028] In addition, in the embodiment, the heights of the above-mentioned first electrode, the above-mentioned second electrode, and the above-mentioned third electrode are different from each other.

[0029] In addition, in the embodiment, it further includes: a passivation layer configured on the above-mentioned substrate to cover the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, the above-mentioned third semiconductor light-emitting element, the above-mentioned common electrode, the above-mentioned first electrode, the above-mentioned second electrode, and the above-mentioned third electrode.

[0030] Advantages of the Invention

[0031] The stacked semiconductor light-emitting element for a display pixel according to the embodiment and the display device including the stacked semiconductor light-emitting element are formed in a stacked structure, and thus have the technical effect of being able to achieve high resolution and high ppi.

[0032] In addition, the embodiment has the technical effect of being able to achieve electrical connection without loss of the light-emitting area of the semiconductor light-emitting element.

[0033] For example, the semiconductor light-emitting element can be connected to an independent electrode and receive an electrical signal through a transparent conductive layer disposed on the lower surface of the semiconductor light-emitting element, without forming a through hole for electrical connection in the semiconductor light-emitting element. Therefore, there is no loss of the light-emitting area, and thus has the technical effect of being able to improve the light-emitting efficiency.

[0034] In addition, a transparent conductive layer 150 is disposed in the region overlapping the semiconductor light-emitting element 130, and thus the efficiency of the light emitted upward from the stacked semiconductor light-emitting element can be improved.

[0035] In addition, the embodiment has the technical effect of improving the light efficiency through light scattering.

[0036] For example, a light conversion layer is disposed under the transparent conductive layer, thereby improving the light efficiency.

[0037] In addition, the embodiment has the technical effect of being able to improve the electrical signal transmission speed.

[0038] For example, the light conversion layer disposed under the transparent conductive layer has higher conductivity than the transparent conductive layer, and thus the signal transmission speed from the electrode to the semiconductor light-emitting element can be improved.

[0039] In addition, the embodiment has the technical effect of improving the light efficiency through light reflection.

[0040] For example, a light reflection layer is disposed under the transparent conductive layer connected to the lowermost semiconductor light-emitting element in the stacked structure, thereby reflecting the light emitted downward in the stacked structure to the upper part, and thus the light efficiency can be improved.

[0041] In addition, in the semiconductor epitaxial layer of the embodiment, there is no need to form a through hole, and thus has the technical effect of being able to reduce the process difficulty.

[0042] In addition, in the embodiment, an electrode connected to the semiconductor light-emitting element is disposed outside the light-emitting region, thereby improving the light output. The semiconductor light-emitting element is disposed on the substrate in a surrounding manner to sufficiently ensure the light-emitting region, and thus has a technical effect of being able to improve the brightness.

[0043] In addition, in the embodiment, the transparent conductive layer 150 is also disposed on the electrode layer disposed in the region that does not overlap with the semiconductor light-emitting element 130, thereby preventing the retroreflection of the light emitted upward from the stacked semiconductor light-emitting element. Therefore, it has a special technical effect of being able to significantly improve the brightness.

[0044] The technical effects of the embodiment are not limited to this, but include all effects that can be grasped through the entire specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a perspective view of the stacked semiconductor light-emitting element for a display pixel according to the embodiment.

[0046] Figure 2 is a conceptual diagram of the stacked semiconductor light-emitting element for a display pixel according to the embodiment.

[0047] Figure 3 is a detailed illustration of Figure 2 the cross-sectional view of the structure of the semiconductor light-emitting element shown.

[0048] Figures 4a to 4g is a process diagram of the stacked semiconductor light-emitting element for a display pixel according to the embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] Hereinafter, with reference to the drawings, the embodiments disclosed in this specification will be described in detail. The suffixes “module” and “unit” of the components used in the following description are given or mixed only for the convenience of writing the specification, and do not have a meaning or function of distinguishing each other. In addition, the drawings are used to help understand the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited to the contents of the drawings. In addition, when referring to a component such as a layer, a region, or a substrate existing “on” another component, this means that it directly exists on the other component or there are other components in between.

[0050] The semiconductor light-emitting elements described in this specification include smart glass, digital TVs, mobile phones, smartphones, laptop computers, digital broadcast terminals, PDAs (personal digital assistants), PMPs (portable multimedia players), navigation devices, Slate PCs, Tablet PCs, Ultra-Books, desktop computers, etc. However, those skilled in the art can easily understand that even for newly developed product forms in the future, as long as they are displayable devices, the structures of the embodiments described in this specification can be applied thereto.

[0051] Next, a stacked semiconductor light-emitting element for a display pixel including a semiconductor light-emitting element according to an embodiment will be described.

[0052] Figure 1 It is a perspective view of a stacked semiconductor light-emitting element for a display pixel according to an embodiment (hereinafter referred to as a'stacked semiconductor light-emitting element'). In the embodiment, the semiconductor light-emitting element may be a micro-LED or a nano-LED, but is not limited thereto.

[0053] Refer to Figure 1 In, a semiconductor light-emitting element 130 is disposed on a substrate 110. The semiconductor light-emitting element 130 includes a first semiconductor light-emitting element 131, a second semiconductor light-emitting element 132, and a third semiconductor light-emitting element 133, and may be formed in a cylindrical shape, but is not limited thereto. The first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133 may be vertically stacked. In addition, a common electrode 120 and first electrodes 125a, 125b, and a third electrode 125c (not shown) are disposed on the substrate 110. And, the substrate 110 includes a CMOS for driving the semiconductor light-emitting element and is formed of silicon or the like.

[0054] The semiconductor light-emitting element 130 is electrically connected to the common electrode 120. The common electrode 120 supplies power to the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133 in common. The first semiconductor light-emitting element 131 is electrically connected to the first electrode 125a. The second semiconductor light-emitting element 132 is electrically connected to the second electrode 125b. The third semiconductor light-emitting element 133 is electrically connected to the third electrode 125c (refer to Figure 2) Electrically connected. The common electrode 120, the first electrode 125a, the second electrode 125b, and the third electrode 125c are electrically connected to a CMOS (Complementary Metal Oxide Semiconductor) disposed in the substrate 110 to drive the semiconductor light-emitting element.

[0055] An insulating layer 140 is disposed below the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133. The insulating layer may be formed of SiO2, but is not limited thereto. The insulating layer 140 prevents electrical short circuits of the semiconductor light-emitting elements and has an adhesive force, so that the stacked structure can be stabilized. In addition, the heat generated by the semiconductor light-emitting element 130 is absorbed, thereby having a technical effect of being able to perform the heat dissipation function of the semiconductor light-emitting element.

[0056] On the other hand, according to the internal research on the stacked semiconductor light-emitting element, the existing stacked semiconductor light-emitting element vertically stacks the light-emitting elements that emit R, G, and B colors, and then forms a through hole in the epitaxial layer of each light-emitting element for electrical connection.

[0057] However, in display devices such as VR, AR, and MR that require high ppi and high resolution, ultra-small semiconductor light-emitting elements are used. In the case of ultra-small micro-LEDs, their size is so small that it is difficult to form through holes in the epitaxial layer. In addition, according to the color of the emitted light, the substances of the epitaxial layer are different, so the etching conditions are different, making it difficult to form through holes. Therefore, it is necessary to study other electrical connection methods instead of electrically connecting the stacked semiconductor light-emitting elements through through holes.

[0058] Refer back to Figure 1 , the first electrode 125a, the second electrode 125b, and the third electrode 125c are electrically connected to the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133 through the first transparent conductive layer 150a, the second transparent conductive layer 150b, and the third transparent conductive layer 150c.

[0059] The stacked semiconductor light-emitting element 130 for a display pixel according to the embodiment electrically connects the semiconductor light-emitting element 130 and the substrate through the common electrode 120, the first electrode 125a, the second electrode 125b, the third electrode 125c, and the transparent conductive layer 150. Therefore, there is no need to form through holes, so there is no area loss of the epitaxial layer, and the through hole process is not performed on the epitaxial layer. Therefore, it has a comprehensive technical effect of improving the reliability of the epitaxial layer.

[0060] In the embodiment, the transparent conductive layer 150 includes a region overlapping with the semiconductor light-emitting element 130 and a region extending outward of the semiconductor light-emitting element 130 without overlapping with the semiconductor light-emitting element 130.

[0061] Thus, according to the embodiment, while being formed into a stacked structure to exhibit high resolution and high ppi, differently from the prior art, the lower electrode layer is disposed outside so as not to overlap with the semiconductor light-emitting element 130, thereby having the technical effect of enabling electrical connection without loss of the light-emitting region.

[0062] In addition, in the embodiment, the transparent conductive layer 150 is disposed in the region overlapping with the semiconductor light-emitting element 130, thereby being able to improve the efficiency of light emitted upward from the stacked semiconductor light-emitting element.

[0063] In addition, differently from the prior art, in the embodiment, the transparent conductive layer 150 is also disposed on the electrode layer disposed in the region not overlapping with the semiconductor light-emitting element 130, thereby preventing the retroreflection of light emitted upward from the stacked semiconductor light-emitting element, and thus having a special technical effect of being able to significantly improve the brightness.

[0064] On the other hand, a light conversion layer 160 is disposed on the lower surface of the transparent conductive layer 150. The light conversion layer 160 includes a first light conversion layer 161, a second light conversion layer 162, and a third light conversion layer 163, and is electrically connected to the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133 through the first transparent conductive layer 150a, the second transparent conductive layer 150b, and the third transparent conductive layer 150c, respectively.

[0065] The light conversion layer 160 is formed into a nanowire structure. The light conversion layer 160 has a lower resistivity than the transparent conductive layer 150. This will be described in detail in Figure 4a In the following.

[0066] On the other hand, the embodiment has a technical feature of changing the light characteristics according to the content of Ag nanowires in the light conversion layer 160. Specifically, when the content of Ag nanowires is small, the light transmittance increases and the light scattering rate increases. In addition, when the content of Ag nanowires increases, the light transmittance decreases and the light reflectance increases. Therefore, in the embodiment, the light conversion layer 160 can adjust the content of Ag nanowires to obtain specific light characteristics.

[0067] In addition, when power is supplied to the semiconductor light-emitting element from the first electrode 125a, the second electrode 125b, and the third electrode 125c, the power is supplied through the light conversion layer 160. Therefore, the stacked semiconductor light-emitting element for a display pixel according to the embodiment and the display device including the stacked semiconductor light-emitting element have the technical effect of improving the electrical signal transmission speed through the light conversion layer.

[0068] In addition, the common electrode 120, the first electrode 125a, the second electrode 125b, and the third electrode 125c are arranged so as to surround the semiconductor light-emitting element 130. Thereby, there is a technical effect of being able to maximize the light-emitting area of the semiconductor light-emitting element disposed on the substrate 110. In addition, there is a technical effect of minimizing the electrical interference between the electrodes.

[0069] In addition, the transparent conductive layer 150 is formed of, for example, ITO (Indium tin oxide). The conductive layer through which the light emitted from the lower part of the stacked semiconductor light-emitting element passes is transparent and has transmissivity, so there is a technical effect of increasing the light traveling upward.

[0070] On the other hand, the content of Ag nanowires in the first light conversion layer 161 is higher than that in the second light conversion layer 162 and the third light conversion layer 163. The first light conversion layer 161 with a high content of Ag nanowires has a low light transmittance and a high light reflectance. In addition, the second light conversion layer 162 and the third light conversion layer 163 with a low content of Ag nanowires have a high light transmittance and a high light scattering rate.

[0071] 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 can be used as light scattering layers. Thereby, there is a technical effect of being able to improve the light efficiency in a display device including a stacked semiconductor light-emitting element.

[0072] Specifically, when extracting light from the first semiconductor light-emitting element 131, it is emitted upward through the second light conversion layer 162. At this time, the emitted light is scattered by the second light conversion layer 162 and the light efficiency can be improved.

[0073] In addition, when extracting light from the first semiconductor light-emitting element 131 and the second semiconductor light-emitting element 132, it goes upward through the third light conversion layer 163. The light is scattered by the third light conversion layer 163 and the light efficiency is improved. Therefore, with the second light conversion layer 162 and the third light conversion layer 163 used as light scattering layers in the embodiment, there is a technical effect of improving the light efficiency.

[0074] In addition, a first light conversion layer 161 disposed on the lower surface of the first transparent conductive layer 161 is used as a light reflection layer. Specifically, when extracting light from the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133, the light directed downward is reflected upward through the first light conversion layer 161. Therefore, with the first light conversion layer 161 being used as a light reflection layer, the embodiment has the technical effect of improving the light extraction efficiency.

[0075] On the other hand, the semiconductor light-emitting element 130, the common electrode 120, the first electrode 125a, the second electrode 125b, and the third electrode 125c disposed on the substrate are surrounded by a passivation layer 140. The passivation layer 140 can protect the semiconductor light-emitting element 130, the common electrode 120, the first electrode 125a, the second electrode 125b, and the third electrode 125c from external impacts and can prevent electrical short circuits. The passivation layer 140 can be formed of SiO2, but is not limited thereto.

[0076] Figure 2 It is a conceptual diagram of a stacked semiconductor light-emitting element of an embodiment.

[0077] Refer to Figure 2 A stacked semiconductor light-emitting element 130 including a first semiconductor light-emitting element 131, a second semiconductor light-emitting element 132, and a third semiconductor light-emitting element 133 is disposed on a substrate 110. In addition, an independent electrode 125 and a common electrode 120 are disposed on the substrate 110. The independent electrode 125 includes a first electrode 125a, a second electrode 125b, and a third electrode 125c. The semiconductor light-emitting element 130 is connected to the independent electrode 125 and the common electrode 120 through a transparent conductive layer 150.

[0078] The transparent conductive layer 150 includes a first transparent conductive layer 150a, a second transparent conductive layer 150b, and a third transparent conductive layer 150c.

[0079] The first semiconductor light-emitting element 131 is electrically connected to the first electrode 125a through the first transparent conductive layer 150a. The second semiconductor light-emitting element 132 is electrically connected to the second electrode 125b through the second transparent conductive layer 150b. The third semiconductor light-emitting element 133 is electrically connected to the third electrode 125c through the third transparent conductive layer 150c.

[0080] In addition, a light conversion layer 160 is 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 light conversion layer 163 is disposed on the lower surface of the third transparent conductive layer 150c.

[0081] The above-mentioned light conversion layer 160 is formed to have a lower resistance than the above-mentioned transparent conductive layer 150. For example, the above-mentioned light conversion layer 160 may be formed of nanowires or may be formed of Ag, but is not limited thereto.

[0082] On the other hand, the first semiconductor light-emitting element 131 is a semiconductor light-emitting element that emits red light, the second semiconductor light-emitting element 132 is a semiconductor light-emitting element that emits green light, and the third semiconductor light-emitting element 133 is a semiconductor light-emitting element that emits blue light, but is not limited thereto.

[0083] At this time, the first electrode 125a, the second electrode 125b, and the third electrode 125c are formed to have different heights. The transparent conductive layer 150 is formed of a light-transmissive material, and when the light generated by the semiconductor light-emitting element located below is directed upward, it can minimize the loss of light and has the technical effect of being able to electrically connect the first electrode 125a, the second electrode 125b, the third electrode 125c, and the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133.

[0084] Moreover, in the embodiment, the fourth electrode 121 is formed on a part of the upper surface corresponding to the form of the upper surface of the semiconductor light-emitting element 130. For example, when the semiconductor light-emitting element 130 has a cylindrical shape, the fourth electrode 121 may have an annular shape.

[0085] The above-mentioned fourth electrode 121 includes a 4-1 electrode 121a, a 4-2 electrode 121b, and a 4-3 electrode 121c that are respectively electrically connected to the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133.

[0086] For example, the first semiconductor light-emitting element 131 is electrically connected to the common electrode 120 through the 4-1 electrode 121a, the second semiconductor light-emitting element 132 is electrically connected to the common electrode 120 through the 4-2 electrode 121b, and the third semiconductor light-emitting element 133 is electrically connected to the common electrode 120 through the 4-3 electrode 121c.

[0087] Next, Figure 3 is a diagram showing in detail the semiconductor light-emitting element in the stacked semiconductor light-emitting element for a display pixel in the embodiment. The following description can be applied to the first semiconductor light-emitting element 131, the second semiconductor light-emitting element 132, and the third semiconductor light-emitting element 133.

[0088] Refer to Figure 3, the semiconductor light-emitting element 130 includes a first-conductive-type semiconductor layer 136, a second-conductive-type semiconductor layer 138, and an active layer 137 disposed therebetween. The first-conductive-type semiconductor layer 136 is an n-type semiconductor layer, and the second-conductive-type semiconductor layer 138 is a p-type semiconductor layer, but is not limited thereto.

[0089] The active layer 137, as a region for generating light, generates light having a specific wavelength band according to the material characteristics of the compound semiconductor. That is, the wavelength band is determined by the energy band gap of the compound semiconductor included in the active layer 137. Therefore, according to the energy band gap of the compound semiconductor included in the active layer 157, the semiconductor light-emitting element 130 of the embodiment can generate UV light, blue light, green light, and red light.

[0090] The above-mentioned first-conductive-type semiconductor layer 156, active layer 157, and second-conductive-type semiconductor layer 158 are made of a compound semiconductor material. For example, the compound semiconductor material may be a group-III-V compound semiconductor material, a group-II-VI compound material, etc. For example, the compound semiconductor material may include GaN, InGaN, AlN, AlInN, AlGaN, AlInGaN, InP, GaAs, GaP, GaInP, etc.

[0091] In addition, a first electrode layer 134 is disposed under the first-conductive-type semiconductor layer 136, and a second electrode layer 139 is disposed on the second-conductive-type semiconductor layer 138. The above-mentioned first electrode layer 134 is electrically connected to one of the first electrode, second electrode, and third electrode through a transparent conductive layer 150 and a light conversion layer 160, and the second electrode layer 139 is electrically connected to the common electrode 120.

[0092] Figures 4a to 4g It is a manufacturing process diagram of a stacked semiconductor light-emitting element for a display pixel of an embodiment.

[0093] Refer to Figure 4a , an epitaxial layer 135 is grown on a growth substrate 115. The above-mentioned epitaxial layer 135 is made of a compound semiconductor material. For example, the compound semiconductor material may be a group-III-V compound semiconductor material, a group-II-VI compound material, etc. For example, the compound semiconductor material may include GaN, InGaN, AlN, AlInN, AlGaN, AlInGaN, InP, GaAs, GaP, GaInP, etc.

[0094] A transparent conductive layer 150 is formed on the above-mentioned epitaxial layer. The above-mentioned transparent conductive layer 150 is formed of a light-transmissive material and has electrical conductivity. The above-mentioned transparent conductive layer 150 is formed of, for example, ITO (Indum Tin Oxcide), but is not limited thereto.

[0095] Next, the light conversion layer 160 is formed on the transparent conductive layer 150. Specifically, a dispersion liquid containing Ag is coated on the transparent conductive layer 150 by spin coating, and then soft baking is performed. The dispersion liquid includes Ag nanowires at the nanoscale. Also, when photonic welding is performed on the transparent conductive layer 150 at about 300 °C, it adheres to the transparent conductive layer and forms into a wire shape with a nanoscale size. The formed light conversion layer has excellent current diffusion characteristics compared to the transmissive conductive layer.

[0096] On the other hand, the light conversion layer 160 formed on the transparent conductive layer 150 is formed to contain different contents of Ag nanowires. The light conversion layer 160 has different light characteristics according to the content of the Ag nanowires. Specifically, if the content of the Ag nanowires is small, the light transmittance increases and the light scattering rate increases. In addition, if the content of the Ag nanowires increases, the light transmittance decreases and the light reflectance increases. Therefore, the light conversion layer 160 adjusts the content of the Ag nanowires to obtain specific light characteristics.

[0097] Thus, the embodiment has the technical effect of being able to improve the transmission speed of the electrical signal transmitted to the semiconductor light-emitting element as the light conversion layer is formed in the form of nanowires containing Ag. In addition, by making the light generated by the semiconductor light-emitting element irradiate upward, it has the comprehensive technical effect of being able to improve the light efficiency.

[0098] Next, referring to Figure 4b , an insulating layer 140a of 1-1 is disposed under the light conversion layer 160. And an insulating layer 140b of 1-2 is formed on the substrate 110 on which the CMOS is formed for preparation. Bonding is performed in such a way that the insulating layer 140a of 1-1 disposed under the light conversion layer 160 and the insulating layer 140b of 1-2 disposed on the substrate 110 face each other. The first insulating layer 140a and the second insulating layer 140b may be SiO2, but are not limited thereto. In the bonding of SiO2 and SiO2, a high-temperature process of about 700 °C was originally required, but plasma treatment can be performed on the surfaces of the first insulating layer 140a1 and the second insulating layer 140b, and thus the bonding process can be performed at a temperature of about 400 °C, so that the epitaxial layer 135 is not damaged due to high temperature.

[0099] Referring to Figure 4c , next, the process of peeling off the growth substrate 115 is performed. In the case of a semiconductor light-emitting element that emits blue light or green light, the epitaxial layer 135 is formed of GaN or the like, and the growth substrate can be peeled off by laser lift-off (LLO) or the like, but is not limited thereto. In the case of a semiconductor light-emitting element that emits red light, the epitaxial layer 135 is formed of GaAs or the like, and the growth substrate can be peeled off by chemical lift-off (CLO) or the like, but is not limited thereto.

[0100] Refer to Figure 4d , a hard mask (not shown) is deposited on the epitaxial layer 135, and a photolithography process and an etching process are performed. The transparent conductive layer 150 is formed in an elliptical shape.

[0101] Refer to Figure 4e , a hard mask (not shown) is deposited on the epitaxial layer 135, and a photolithography process and an etching process are performed. The above-mentioned epitaxial layer 135 is etched into an elliptical shape. The above-mentioned epitaxial layer is formed to have an area smaller than that of the transparent conductive layer 150. Next, the exposed transparent conductive layer 150 and the epitaxial layer 135 are covered with an insulating layer. And, planarization is performed through a CMP process.

[0102] Refer to Figure 4f , a first through-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 second through-hole is formed from the surface of the above-mentioned insulating layer to the upper surface of the substrate so as not to overlap with the semiconductor light-emitting element 135 and the above-mentioned transparent conductive layer 150.

[0103] An independent electrode 125 is formed in the above-mentioned first through-hole. The above-mentioned independent electrode 125 is electrically connected to the semiconductor light-emitting element 135 through the above-mentioned transparent conductive layer 150. In addition, the above-mentioned independent electrode 125 is electrically connected to the semiconductor light-emitting element 135 through a light conversion layer 160 disposed on the lower surface of the above-mentioned transparent conductive layer 150.

[0104] The above-mentioned light conversion layer 160 can be formed in the form of Ag nanowires, but is not limited thereto. Thus, the above-mentioned light conversion layer 160 can have a lower resistance than the above-mentioned transparent conductive layer 150, and thus has a technical effect of being able to improve the transmission speed of the electrical signal transmitted from the above-mentioned independent electrode 125 to the above-mentioned semiconductor light-emitting element 135.

[0105] Next, a common electrode 120 is formed in the above-mentioned second through-hole. The above-mentioned common electrode 120 is electrically connected to the above-mentioned semiconductor light-emitting element 135 through a fourth electrode 121. The above-mentioned fourth electrode is formed in an annular shape, for example, at the edge of the upper surface of the above-mentioned semiconductor light-emitting element 135, but is not limited thereto.

[0106] By repeatedly performing the above manufacturing process, a semiconductor light-emitting element having a stacked structure is manufactured. Figure 4g

[0107] Refer to Figure 4g , a second semiconductor light-emitting element 132 is disposed on the first semiconductor light-emitting element 131, and a third semiconductor light-emitting element 133 is disposed on the above-mentioned second semiconductor light-emitting element 132.

[0108] The above-mentioned first semiconductor light-emitting element 131 is connected to the first electrode 125a through the first transparent conductive layer 150a. In addition, a first light conversion layer 161 is disposed on the lower surface of the first transparent conductive layer 150a.

[0109] The above-mentioned second semiconductor light-emitting element 132 is connected to the second electrode 125b through the second transparent conductive layer 150b. In addition, a second light conversion layer 162 is disposed on the lower surface of the second transparent conductive layer 150b.

[0110] The above-mentioned third semiconductor light-emitting element 133 is connected to the third electrode 125c through the third transparent conductive layer 150c. In addition, a third light conversion layer 163 is disposed on the lower surface of the third transparent conductive layer 150c.

[0111] At this time, the second light conversion layer 162 and the third light conversion layer 163 can be used as light scattering layers. Thereby, the second light conversion layer 162 scatters the light emitted from the first semiconductor light-emitting element 131, thereby increasing the amount of light emitted upward. In addition, the third light conversion layer 163 scatters the light emitted from the first semiconductor light-emitting element 131 and the second semiconductor light-emitting element 132, increasing the amount of light emitted upward.

[0112] Therefore, as the light conversion layer disposed on the lower surface of the transparent conductive layer is used as a light scattering layer in the embodiment, there is a technical effect that the light efficiency can be improved in the stacked semiconductor light-emitting element.

[0113] In addition, the first light conversion layer 161 can be used as a light reflection layer. The first light conversion layer 161 reflects the light emitted downward from the first semiconductor light-emitting element 131 to increase the amount of light emitted upward. Therefore, in the embodiment, the light conversion layer disposed on the lower surface of the transparent conductive layer is used as a light reflection layer, thereby having a technical effect that the light efficiency can be improved in the stacked semiconductor light-emitting element. In particular, when the first semiconductor light-emitting element 131 emits red light, although the luminous efficiency is low, the light efficiency can be improved through the light reflection layer to correspond to the semiconductor light-emitting element that emits blue light or green light.

[0114] The stacked semiconductor light-emitting element for a display pixel according to the embodiment and a display device including the stacked semiconductor light-emitting element are formed in a stacked structure, thereby having a technical effect that high resolution and high ppi can be realized.

[0115] In addition, the embodiment has a technical effect that electrical connection can be achieved without loss of the light-emitting region of the semiconductor light-emitting element.

[0116] For example, the semiconductor light-emitting element is connected to an electrode through a transparent conductive layer disposed on the lower surface, thereby receiving an electrical signal. There is no need to form a through hole for electrical connection on the semiconductor light-emitting element, so that no loss of the light-emitting region occurs, and thus a technical effect of improving the light-emitting efficiency can be achieved.

[0117] In addition, a transparent conductive layer 150 is disposed on a region overlapping with the semiconductor light-emitting element 130, thereby improving the efficiency of light emitted upward from the stacked semiconductor light-emitting element.

[0118] In addition, the embodiment has a technical effect of improving the light efficiency through light scattering.

[0119] For example, by disposing a light conversion layer below the transparent conductive layer, the light efficiency can be improved.

[0120] In addition, the embodiment has a technical effect of improving the electrical signal transmission speed.

[0121] For example, the light conversion layer disposed below the transparent conductive layer has higher conductivity than the transparent conductive layer, so that the signal transmission speed from the electrode to the semiconductor light-emitting element can be improved.

[0122] In addition, the embodiment has a technical effect of improving the light efficiency through light reflection.

[0123] For example, a light reflection layer is disposed below the transparent conductive layer connected to the semiconductor light-emitting element disposed at the bottom in the stacked structure, so that the light emitted downward in the stacked structure is reflected upward, thereby improving the light efficiency.

[0124] In addition, in the embodiment, there is no need to form a through hole in the semiconductor epitaxial layer, so that a technical effect of reducing the difficulty of the process can be achieved.

[0125] In addition, in the embodiment, the electrode connected to the semiconductor light-emitting element is disposed outside the light-emitting region to improve the light output, and the semiconductor light-emitting element is disposed on the substrate in a surrounding manner, thereby sufficiently ensuring the light-emitting region, and thus having a technical effect of improving the brightness.

[0126] In addition, in the embodiment, a transparent conductive layer 150 is also disposed on the electrode layer disposed in a region not overlapping with the semiconductor light-emitting element 130, thereby preventing the retroreflection of the light emitted upward from the stacked semiconductor light-emitting element, and thus having a special technical effect of significantly improving the brightness.

[0127] The above detailed description is only illustrative in all aspects and should not be construed in a limiting sense. The scope of the embodiment should be determined according to the reasonable interpretation of the appended claims, and all changes within the equivalent scope of the embodiment are included in the scope of the embodiment.

[0128] (Description of the reference numerals in the drawings)

[0129] 110: Substrate

[0130] 115: Growth substrate

[0131] 120: Common electrode

[0132] 121: Fourth electrode

[0133] 121a: 4-1 electrode

[0134] 121b: 4-2 electrode

[0135] 121c: 4-3 electrode

[0136] 125a: First electrode

[0137] 125b: Second electrode

[0138] 125c: Third electrode

[0139] 130: Semiconductor light-emitting element

[0140] 131: First semiconductor light-emitting element

[0141] 132: Second semiconductor light-emitting element

[0142] 133: Third semiconductor light-emitting element

[0143] 134: First electrode layer

[0144] 135: Epitaxial layer

[0145] 136: First conductive-type semiconductor layer

[0146] 137: Active layer

[0147] 138: Second conductive-type semiconductor layer

[0148] 139: Second electrode layer

[0149] 140: Passivation layer (insulating layer)

[0150] 141a: 1-1 insulating layer

[0151] 141b: 1-2 insulating layer

[0152] 150: Transparent conductive layer

[0153] 150a: First transparent conductive layer

[0154] 150b: Second transparent conductive layer

[0155] 160: Light conversion layer

[0156] 161: The first light conversion layer

[0157] 162: The second light conversion layer

[0158] 163: The third light conversion layer

Claims

1. A stacked semiconductor light-emitting element for a display pixel, comprising: A substrate; A first semiconductor light-emitting element, a second semiconductor light-emitting element, and a third semiconductor light-emitting element, which are vertically arranged on the above-mentioned substrate; A common electrode, which is electrically connected to the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element; A first electrode, a second electrode, and a third electrode, which are arranged separately on one side of each semiconductor light-emitting element so as not to overlap with the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element in the vertical direction and are electrically connected to each semiconductor light-emitting element respectively; And A first transparent conductive layer, a second transparent conductive layer, and a third transparent conductive layer, which are in contact with one surface of the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element respectively, and are connected to the above-mentioned first electrode, the above-mentioned second electrode, and the above-mentioned third electrode respectively, The above-mentioned first transparent conductive layer, the above-mentioned second transparent conductive layer, and the above-mentioned third transparent conductive layer include regions overlapping with the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element and regions not overlapping with the above-mentioned first semiconductor light-emitting element, the above-mentioned second semiconductor light-emitting element, and the above-mentioned third semiconductor light-emitting element, The above-mentioned stacked semiconductor light-emitting element for a display pixel includes: a first light conversion layer, a second light conversion layer, and a third light conversion layer, which are respectively arranged on the lower surfaces of the above-mentioned first transparent conductive layer, the above-mentioned second transparent conductive layer, and the above-mentioned third transparent conductive layer.

2. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein The above-mentioned first transparent conductive layer extends horizontally on one surface of the above-mentioned first semiconductor light-emitting element and is connected to the above-mentioned first electrode, The above-mentioned second transparent conductive layer extends horizontally on one surface of the above-mentioned second semiconductor light-emitting element and is connected to the above-mentioned second electrode, The above-mentioned third transparent conductive layer extends horizontally on one surface of the above-mentioned third semiconductor light-emitting element and is connected to the above-mentioned third electrode.

3. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein The above-mentioned first transparent conductive layer has a larger area than the above-mentioned first semiconductor light-emitting element.

4. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein The above-mentioned common electrode and the above-mentioned first electrode, the above-mentioned second electrode, and the above-mentioned third electrode surround the semiconductor light-emitting element.

5. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein The above-mentioned first light conversion layer includes a light reflection layer.

6. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein The above-mentioned second light conversion layer and the above-mentioned third light conversion layer include a light scattering layer.

7. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein The above-mentioned first light conversion layer, the second light conversion layer, and the third light conversion layer include nanowires containing Ag.

8. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein: the common electrode includes a fourth electrode connected to the first semiconductor light-emitting element, the second semiconductor light-emitting element, and the third semiconductor light-emitting element; the fourth electrode is disposed on at least a part of the other surface of the first semiconductor light-emitting element, the second semiconductor light-emitting element, and the third semiconductor light-emitting element.

9. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein: the heights of the first electrode, the second electrode, and the third electrode are different from each other.

10. The stacked semiconductor light-emitting element for a display pixel according to claim 1, wherein It further includes: a passivation layer, which is disposed on the substrate and covers the first semiconductor light-emitting element, the second semiconductor light-emitting element, the third semiconductor light-emitting element, the common electrode, the first electrode, the second electrode, and the third electrode.

11. The stacked semiconductor light-emitting element for a display pixel according to claim 7, wherein: the first light conversion layer contains a higher content of the nanowires of Ag than the second light conversion layer and the third light conversion layer.

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