Light-emitting element, manufacturing method thereof, and display device using same

Abstract

The present disclosure is applicable to the technical field related to a display device, and relates to, for example, a light-emitting element, a manufacturing method thereof, and a display device using same. The light-emitting element according to an embodiment of the present disclosure may comprise: a first conductivity-type semiconductor layer; an active layer positioned on a first surface of the first conductivity-type semiconductor layer; a second conductivity-type semiconductor layer positioned on the active layer; a reflective layer positioned on a second surface of the first conductivity-type semiconductor layer; and a light extraction layer positioned on the second conductivity-type semiconductor layer, wherein the light extraction layer comprises: a column structure including a plurality of unit columns positioned on the first conductivity-type semiconductor layer; and a first conductive layer locally positioned on the unit columns.

Description

Light-emitting element, manufacturing method thereof, and display device using the same

[0001] The present disclosure is applicable to the technical field related to display devices, and relates to, for example, a light-emitting element, a method for manufacturing the same, and a display device using the same.

[0002] Recently, display devices with superior characteristics, such as thinness and flexibility, are being developed in the display technology field. In contrast, the major displays currently commercialized are represented by LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode).

[0003] However, in the case of LCD, there are problems such as slow response time and difficulty in implementing flexibility, and in the case of OLED, there are problems such as short lifespan and poor mass production yield.

[0004] Meanwhile, a light-emitting diode (LED) is a semiconductor light-emitting device well known for converting electric current into light. Starting with the commercialization of a red LED using a GaAsP compound semiconductor in 1962, it has been used as a light source for display images in electronic devices including information and communication devices, along with a green LED of the GaP:N series. Therefore, a method for solving the above-mentioned problem by implementing a display using a semiconductor light-emitting device can be presented. The semiconductor light-emitting device has various advantages such as a long lifespan, low power consumption, excellent initial driving characteristics, and high vibration resistance compared to a filament-based light-emitting device.

[0005] To improve the light extraction efficiency and optical characteristics of these light-emitting devices, a reflective film is used on the top or bottom of the light-emitting device, but a rough surface (surface roughness) can be additionally formed on the light extraction surface to maximize the light extraction efficiency.

[0006] However, as display devices become more high-definition, the size of the light-emitting elements used as pixels becomes smaller, and accordingly, the process of forming surface roughness has a pattern in the nanometer unit, making it increasingly difficult to use a general process.

[0007] In particular, as the size of light-emitting elements is reduced to micrometer units, a phenomenon occurs in which the left / right or up / down color viewing angles become uneven depending on the light extraction method and shape of the light-emitting element.

[0008] Although this phenomenon can be improved to some extent through image quality compensation in the display device or module, it is difficult to fundamentally resolve the problem caused by color viewing angle distortion.

[0009] Therefore, a solution to these problems is required.

[0010] The technical problem to be solved by the present disclosure is to provide a light-emitting device capable of improving the light extraction efficiency of the light-emitting device, a method for manufacturing the same, and a display device using the same.

[0011] In addition, the present invention aims to provide a light-emitting device capable of efficiently implementing a light extraction structure of the light-emitting device, a method for manufacturing the same, and a display device using the same.

[0012] In addition, the present invention aims to provide a light-emitting element capable of improving the efficiency of a display device along with the improvement of the light extraction efficiency of the light-emitting element, a method for manufacturing the same, and a display device using the same.

[0013] In addition, the present invention aims to provide a light-emitting element capable of improving the phenomenon in which the color viewing angle of a display device becomes uneven depending on the light-emitting element, a method for manufacturing the same, and a display device using the same.

[0014] Furthermore, the purpose of one embodiment of the present invention is to solve various problems not mentioned herein. Those skilled in the art will understand the full scope of the invention through the specification and drawings.

[0015] A light-emitting device according to an embodiment of the present disclosure for achieving the above object includes: a first conductive semiconductor layer; an active layer positioned on a first surface of the first conductive semiconductor layer; a second conductive semiconductor layer positioned on the active layer; a reflective layer positioned on a second surface of the first conductive semiconductor layer; and a light extraction layer positioned on the second conductive semiconductor layer, wherein the light extraction layer may include a columnar structure including a plurality of unit columns positioned on the first conductive semiconductor layer; and a first conductive layer locally positioned on the unit columns.

[0016] In order to achieve the above object, a method for manufacturing a light-emitting device according to an embodiment of the present disclosure includes a method for manufacturing a light-emitting device including a semiconductor layer including a first conductive semiconductor layer, a second conductive semiconductor layer, a third conductive semiconductor layer, and an active layer positioned between the first conductive semiconductor layer and the second conductive semiconductor layer, the method including: forming a first conductive layer on the third conductive semiconductor layer; etching the first conductive layer; and etching the third conductive semiconductor layer using the first conductive layer as a mask to form a light-extracting layer including a columnar structure including a plurality of unit columns.

[0017] In order to achieve the above object, a display device according to an embodiment of the present disclosure is a display device using a light-emitting element, comprising: a wiring substrate on which first electrodes are arranged; a light-emitting element including a semiconductor layer disposed on the wiring substrate to form a unit subpixel; a first connection electrode electrically connecting the first electrode to one side of the semiconductor layer of the light-emitting element; a planarization layer covering the light-emitting element and the first connection electrode; and a second connection electrode positioned on the planarization layer and electrically connected to the other side of the semiconductor layer of the light-emitting element, wherein the light-emitting element includes a light-extracting layer positioned on the semiconductor layer, and the light-extracting layer may include a columnar structure including a plurality of unit columns positioned on the semiconductor layer; and a first conductive layer locally positioned on the unit columns.

[0018] According to one embodiment of the present disclosure, the following effects are achieved.

[0019] First, the light extraction structure of the light-emitting element can be efficiently implemented, thereby improving the light extraction efficiency of the light-emitting element.

[0020] In addition, the efficiency of the display device can be improved along with the improvement of the light extraction efficiency of the light-emitting element.

[0021] In addition, it is possible to improve the phenomenon in which the color viewing angle of a display device becomes uneven depending on the light-emitting element.

[0022] Furthermore, according to another embodiment of the present disclosure, there are additional technical effects not mentioned herein. Those skilled in the art will understand the full scope of the specification and drawings.

[0023] Figure 1 is an exemplary diagram of a living room of a house in which a display device according to an embodiment is placed.

[0024] Fig. 2 is a block diagram schematically showing a display device according to an embodiment.

[0025] Figure 3 is a circuit diagram showing an example of a pixel of Figure 2.

[0026] FIG. 4 is an enlarged view of the first panel area in the display device of FIG. 1.

[0027] Figure 5 is a cross-sectional view along line B1-B2 of area A2 of Figure 4.

[0028] Fig. 6 is an exemplary diagram showing a light-emitting element according to an embodiment assembled on a substrate by a self-assembly method.

[0029] Fig. 7 is a cross-sectional view showing a light-emitting element according to the first embodiment of the present disclosure.

[0030] Fig. 8 is an enlarged cross-sectional view of a portion of a light-emitting device according to embodiments of the present disclosure.

[0031] Fig. 9 is a photograph of a portion of Fig. 8.

[0032] Fig. 10 is an enlarged cross-sectional view of a portion of a light-emitting element according to a modified embodiment of the present disclosure.

[0033] FIG. 11 and FIG. 12 are cross-sectional views illustrating a manufacturing process of a light-emitting element according to one embodiment of the present disclosure.

[0034] FIGS. 13 to 18 are photographs showing a manufacturing process of a light-emitting device according to one embodiment of the present disclosure.

[0035] Figures 19 and 20 are photographs showing changes in the first conductive layer as the etching time increases.

[0036] Figures 21 to 23 are photographs showing changes in the etching time of the third conductive semiconductor layer as it increases.

[0037] Fig. 24 is a cross-sectional view showing a light-emitting element according to the second embodiment of the present disclosure.

[0038] Fig. 25 is a cross-sectional view showing a light-emitting element according to a third embodiment of the present disclosure.

[0039] Fig. 26 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.

[0040] Fig. 27 is a cross-sectional view showing a display device according to another embodiment of the present disclosure.

[0041] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components will be given the same reference numbers, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably only for the convenience of writing the specification, and do not in themselves have distinct meanings or roles. In addition, when describing the embodiments disclosed in this specification, if it is determined that a specific description of a related known technology may obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical ideas disclosed in this specification by the attached drawings.

[0042] Furthermore, for the convenience of explanation, each drawing is described, but it is also within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two drawings.

[0043] Additionally, when an element such as a layer, region or substrate is referred to as existing "on" another element, it will be understood that this may be directly on the other element, or that there may be intermediate elements in between.

[0044] The display device described in this specification is a concept that includes all display devices that display information as a unit pixel or a set of unit pixels. Therefore, it can be applied not only to finished products but also to components. For example, a panel corresponding to a component of a digital TV is also a display device in this specification. Finished products may include mobile phones, smart phones, laptop computers, digital broadcasting terminals, personal digital assistants (PDAs), portable multimedia players (PMPs), navigation systems, slate PCs, tablet PCs, Ultrabooks, digital TVs, desktop computers, etc.

[0045] However, those skilled in the art will readily recognize that the configuration according to the embodiments described herein may be applied to devices capable of displaying, even if they are new product types developed in the future.

[0046] The semiconductor light-emitting device mentioned in the specification includes LEDs, micro LEDs, etc., and may be used interchangeably.

[0047]

[0048] FIG. 1 illustrates a living room of a house in which a display device according to one embodiment is arranged.

[0049] A display device (100) according to one embodiment can display the status of various electronic products such as a washing machine (101), a robot vacuum cleaner (102), and an air purifier (103), and can communicate with each electronic product based on IoT and control each electronic product based on user setting data.

[0050] A display device (100) according to an embodiment may include a flexible display manufactured on a thin and flexible substrate. The flexible display can be bent or rolled like paper while maintaining the characteristics of a conventional flat panel display.

[0051] In a flexible display, visual information can be realized by independently controlling the light emission of unit pixels arranged in a matrix form. A unit pixel refers to the smallest unit for realizing a single color. The unit pixels of a flexible display can be realized by light-emitting elements. In an embodiment, the light-emitting elements may be micro-LEDs or nano-LEDs, but are not limited thereto.

[0052]

[0053] FIG. 2 is a block diagram schematically showing a display device according to one embodiment, and FIG. 3 is a circuit diagram showing an example of a pixel of FIG. 2.

[0054] Referring to FIGS. 2 and 3, a display device according to one embodiment may include a display panel (10), a driving circuit (20), a scan driving unit (30), and a power supply circuit (50).

[0055] The display device (100) of one embodiment can drive light-emitting elements in an active matrix (AM) manner or a passive matrix (PM) manner.

[0056] The driving circuit (20) may include a data driving unit (21) and a timing control unit (22).

[0057] The display panel (10) can be divided into a display area (DA) and a non-display area (NDA) arranged around the display area (DA). The display area (DA) is an area where pixels (PX) are formed to display an image. The display panel (10) can include data lines (D1 to Dm, m is an integer greater than or equal to 2), scan lines (S1 to Sn, n is an integer greater than or equal to 2) intersecting the data lines (D1 to Dm), a high-potential voltage line to which a high-potential voltage is supplied, a low-potential voltage line to which a low-potential voltage is supplied, and pixels (PX) connected to the data lines (D1 to Dm) and the scan lines (S1 to Sn).

[0058] Each of the pixels (PX) may include a first sub-pixel (PX1), a second sub-pixel (PX2), and a third sub-pixel (PX3). The first sub-pixel (PX1) may emit a first color light of a first wavelength, the second sub-pixel (PX2) may emit a second color light of a second wavelength, and the third sub-pixel (PX3) may emit a third color light of a third wavelength. The first color light may be red light, the second color light may be green light, and the third color light may be blue light, but the present invention is not limited thereto. In addition, although FIG. 2 illustrates that each of the pixels (PX) includes three sub-pixels, the present invention is not limited thereto. That is, each of the pixels (PX) may include four or more sub-pixels.

[0059] Each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) may be connected to at least one of the data lines (D1 to Dm), at least one of the scan lines (S1 to Sn), and a high-potential voltage line. The first sub-pixel (PX1) may include light-emitting elements (LD), a plurality of transistors for supplying current to the light-emitting elements (LD), and at least one capacitor (Cst), as shown in FIG. 3.

[0060] Although not shown in the drawing, each of the first sub-pixel (PX1), the second sub-pixel (PX2) and the third sub-pixel (PX3) may include only one light-emitting element (LD) and at least one capacitor (Cst).

[0061] Each of the light emitting elements (LDs) may be a semiconductor light emitting diode including a first electrode, a plurality of conductive semiconductor layers, and a second electrode. Here, the first electrode may be an anode electrode, and the second electrode may be a cathode electrode, but this is not limited thereto.

[0062] Referring to FIG. 3, a plurality of transistors may include a driving transistor (DT) that supplies current to light-emitting elements (LD), and a scan transistor (ST) that supplies a data voltage to a gate electrode of the driving transistor (DT). The driving transistor (DT) may include a gate electrode connected to a source electrode of the scan transistor (ST), a source electrode connected to a high-potential voltage line to which a high-potential voltage is applied, and a drain electrode connected to first electrodes of the light-emitting elements (LD). The scan transistor (ST) may include a gate electrode connected to a scan line (Sk, where k is an integer satisfying 1 ≤ k ≤ n), a source electrode connected to the gate electrode of the driving transistor (DT), and a drain electrode connected to a data line (Dj, where j is an integer satisfying 1 ≤ j ≤ m).

[0063] A capacitor (Cst) is formed between the gate electrode and the source electrode of the driving transistor (DT). The storage capacitor (Cst) can charge the difference between the gate voltage and the source voltage of the driving transistor (DT).

[0064] The driving transistor (DT) and the scan transistor (ST) may be formed as thin film transistors. In addition, although FIG. 3 mainly describes the driving transistor (DT) and the scan transistor (ST) as being formed as P-type MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), the present invention is not limited thereto. The driving transistor (DT) and the scan transistor (ST) may also be formed as N-type MOSFETs. In this case, the positions of the source electrodes and drain electrodes of each of the driving transistor (DT) and the scan transistor (ST) may be changed.

[0065] In addition, although FIG. 3 illustrates that each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) includes a 2T1C (2 Transistor - 1 capacitor) having one driving transistor (DT), one scan transistor (ST), and one capacitor (Cst), the present disclosure is not limited thereto. Each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) may include a plurality of scan transistors (ST) and a plurality of capacitors (Cst).

[0066] Referring again to FIG. 2, the driving circuit (20) outputs signals and voltages for driving the display panel (10). For this purpose, the driving circuit (20) may include a data driving unit (21) and a timing control unit (22).

[0067] The data driving unit (21) receives digital video data (DATA) and a source control signal (DCS) from the timing control unit (22). The data driving unit (21) converts digital video data (DATA) into analog data voltages according to the source control signal (DCS) and supplies the converted data to the data lines (D1 to Dm) of the display panel (10).

[0068] The timing control unit (22) receives digital video data (DATA) and timing signals from the host system. The timing signals may include a vertical sync signal, a horizontal sync signal, a data enable signal, and a dot clock. The host system may be an application processor of a smartphone or tablet PC, a monitor, a system-on-chip of a TV, etc.

[0069] The scan driving unit (30) receives a scan control signal (SCS) from the timing control unit (22). The scan driving unit (30) generates scan signals according to the scan control signal (SCS) and supplies them to the scan lines (S1 to Sn) of the display panel (10). The scan driving unit (30) may include a plurality of transistors and may be formed in a non-display area (NDA) of the display panel (10). Alternatively, the scan driving unit (30) may be formed as an integrated circuit, in which case it may be mounted on a gate flexible film attached to the other side of the display panel (10).

[0070] The power supply circuit (50) can generate a high-potential voltage (VDD) and a low-potential voltage (VSS) for driving light-emitting elements (LD) of the display panel (10) from the main power supply and supply them to the high-potential voltage line and the low-potential voltage line of the display panel (10). In addition, the power supply circuit (50) can generate and supply driving voltages for driving the driving circuit (20) and the scan driving unit (30) from the main power supply.

[0071]

[0072] Figure 4 is an enlarged view of the first panel area in the display device of Figure 1.

[0073] According to FIG. 4, a display device (100) according to one embodiment can be manufactured by mechanically and electrically connecting a plurality of panel areas, such as a first panel area (A1), through tiling.

[0074] The first panel area (A1) may include a plurality of light-emitting elements (150) arranged for each unit pixel (PX in FIG. 2).

[0075] For example, a unit pixel (PX) may include a first sub-pixel (PX1), a second sub-pixel (PX2), and a third sub-pixel (PX3). For example, a plurality of red light-emitting elements (150R) may be arranged in the first sub-pixel (PX1), a plurality of green light-emitting elements (150G) may be arranged in the second sub-pixel (PX2), and a plurality of blue light-emitting elements (150B) may be arranged in the third sub-pixel (PX3). The unit pixel (PX) may further include a fourth sub-pixel in which no light-emitting element is arranged, but this is not limited thereto. Meanwhile, the light-emitting element (150) may be a semiconductor light-emitting element.

[0076]

[0077] Figure 5 is a cross-sectional view along line B1-B2 of area A2 of Figure 4.

[0078] Referring to FIG. 5, a display device (100) according to one embodiment may include a substrate (200), assembly wiring (201, 202), a first insulating layer (211a), a second insulating layer (211b), a third insulating layer (206), and a plurality of light-emitting elements (150).

[0079] The assembly wiring may include a first assembly wiring (201) and a second assembly wiring (202) that are spaced apart from each other. The first assembly wiring (201) and the second assembly wiring (202) may be provided to generate a dielectrophoretic force for assembling the light emitting element (150). In addition, the first assembly wiring (201) and the second assembly wiring (202) may be electrically connected to electrodes of the light emitting element to function as electrodes of the display panel.

[0080] The assembly wiring (201, 202) may be formed of a light-transmitting electrode (ITO) or may include a metal material with excellent electrical conductivity. For example, the assembly wiring (201, 202) may be formed of at least one of titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), molybdenum (Mo), or an alloy thereof.

[0081] A first insulating layer (211a) may be placed between the first assembly wiring (201) and the second assembly wiring (202), and a second insulating layer (211b) may be placed on the first assembly wiring (201) and the second assembly wiring (202). The first insulating layer (211a) and the second insulating layer (211b) may be an oxide film, a nitride film, or the like, but are not limited thereto.

[0082] The light emitting element (150) may include a red light emitting element (150), a green light emitting element (150G), and a blue light emitting element (150B0) to form a unit pixel (sub-pixel), but is not limited thereto, and may also include a red phosphor, a green phosphor, etc. to implement red and green, respectively.

[0083] The substrate (200) may be formed of glass or polyimide. In addition, the substrate (200) may include a flexible material such as polyethylene naphthalate (PEN) or polyethylene terephthalate (PET). In addition, the substrate (200) may be a transparent material, but is not limited thereto.

[0084] The third insulating layer (206) may include an insulating and flexible material such as polyimide, PEN, PET, etc., and may be formed integrally with the substrate (200) to form a single substrate.

[0085] The third insulating layer (206) may be a conductive adhesive layer having adhesive properties and conductivity, and the conductive adhesive layer may be flexible to enable a flexible function of the display device. For example, the third insulating layer (206) may be a conductive adhesive layer such as an anisotropic conductive film (ACF) or an anisotropic conductive medium, a solution containing conductive particles, etc. The conductive adhesive layer may be a layer that is electrically conductive in a direction vertical to the thickness, but electrically insulating in a direction horizontal to the thickness.

[0086] The third insulating layer (206) may include an assembly hole (203) into which a light-emitting element (150) is inserted (see FIG. 6). Therefore, during self-assembly, the light-emitting element (150) can be easily inserted into the assembly hole (203) of the third insulating layer (206). The assembly hole (203) may be referred to as an insertion hole, a fixing hole, an alignment hole, or the like.

[0087] The gap between the assembly wiring (201, 202) is formed to be smaller than the width of the light-emitting element (150) and the width of the assembly hole (203), so that the assembly position of the light-emitting element (150) can be fixed more precisely using an electric field.

[0088] A third insulating layer (206) is formed on the assembly wiring (201, 202) to protect the assembly wiring (201, 202) from the fluid (1200) and prevent leakage of current flowing in the assembly wiring (201, 202). The third insulating layer (206) may be formed as a single layer or multiple layers of an inorganic insulator such as silica or alumina or an organic insulator.

[0089] Additionally, the third insulating layer (206) may include an insulating and flexible material such as polyimide, PEN, PET, etc., and may be formed integrally with the substrate (200) to form a single substrate.

[0090] The third insulating layer (206) may be an adhesive insulating layer or a conductive adhesive layer having conductivity. The third insulating layer (206) may be flexible, thereby enabling a flexible function of the display device.

[0091] The third insulating layer (206) has a partition wall, and an assembly hole (203) can be formed by this partition wall. For example, when forming the substrate (200), a part of the third insulating layer (206) is removed, so that each of the light-emitting elements (150) can be assembled into the assembly hole (203) of the third insulating layer (206).

[0092] An assembly hole (203) is formed in the substrate (200) to which light-emitting elements (150) are coupled, and the surface where the assembly hole (203) is formed can come into contact with a fluid (1200). The assembly hole (203) can guide the exact assembly position of the light-emitting elements (150).

[0093] Meanwhile, the assembly hole (203) may have a shape and size corresponding to the shape of the light-emitting element (150) to be assembled at the corresponding position. Accordingly, it is possible to prevent another light-emitting element from being assembled in the assembly hole (203) or multiple light-emitting elements from being assembled.

[0094]

[0095] FIG. 6 is a drawing showing an example in which a light-emitting element according to one embodiment is assembled on a substrate by a self-assembly method, and the self-assembly method of the light-emitting element is described with reference to FIG. 6.

[0096] The substrate (200) may be a panel substrate of a display device. In the following description, the substrate (200) is described as a panel substrate of a display device, but the embodiment is not limited thereto.

[0097] Referring to FIG. 6, a plurality of light-emitting elements (150) may be placed in a chamber (1300) filled with a fluid (1200). The fluid (1200) may be, but is not limited to, water such as ultrapure water. The chamber may be referred to as a tank, a container, a vessel, or the like.

[0098] Thereafter, the substrate (200) may be placed on the chamber (1300). Depending on the embodiment, the substrate (200) may be introduced into the chamber (1300).

[0099] As shown in FIG. 5, a pair of assembly wirings (201, 202) corresponding to each light emitting element (150) to be assembled can be arranged on the substrate (200).

[0100] Referring to FIG. 6, after the substrate (200) is placed, an assembly device (1100) including a magnetic body can move along the substrate (200). For example, a magnet or an electromagnet can be used as the magnetic body. The assembly device (1100) can move in contact with the substrate (200) to maximize the area affected by the magnetic field within the fluid (1200).

[0101] In some embodiments, the assembly device (1100) may include a plurality of magnetic bodies or may include magnetic bodies of a size corresponding to the substrate (200). In this case, the movement distance of the assembly device (1100) may be limited within a predetermined range.

[0102] By the magnetic field generated by the assembly device (1100), the light emitting element (150) within the chamber (1300) can move toward the assembly device (1100).

[0103] The light emitting element (150) may move toward the assembly device (1100) and enter the assembly hole (203) by the dielectric electrophoretic force (DEP force) to come into contact with the substrate (200).

[0104] Specifically, the assembly wiring (201, 202) forms an electric field by an externally supplied power source, and a dielectric force can be formed between the assembly wiring (201, 202) by this electric field. The light-emitting element (150) can be fixed to the assembly hole (203) on the substrate (200) by this dielectric force.

[0105] By the electric field applied by the assembly wiring (201, 202) formed on the substrate (200), the light emitting element (150) in contact with the substrate (200) can be prevented from being detached by the movement of the assembly device (1100). According to an embodiment, by the self-assembly method using the electromagnetic field described above, the time required for each of the light emitting elements (150) to be assembled on the substrate (200) can be drastically shortened, so that a large-area, high-pixel display can be implemented more quickly and economically.

[0106] At this time, a predetermined solder layer (not shown) is formed between the light-emitting element (150) assembled on the assembly hole (203) of the substrate (200) and the assembly electrode, thereby improving the bonding strength of the light-emitting element (150).

[0107] Next, a molding layer (not shown) may be formed in the assembly hole (203) of the substrate (200). The molding layer may be a light-transmitting resin or a resin containing a reflective material or a scattering material.

[0108]

[0109] Fig. 7 is a cross-sectional view showing a light-emitting device according to a first embodiment of the present disclosure. Fig. 8 is an enlarged cross-sectional view of a portion of a light-emitting device according to embodiments of the present disclosure. Fig. 9 is a photograph of a portion of Fig. 8. Fig. 10 is an enlarged cross-sectional view of a portion of a light-emitting device according to a modified embodiment of the present disclosure.

[0110] Referring to FIG. 7, the light-emitting device (300) according to the present embodiment may include a semiconductor layer (310) including a first conductive semiconductor layer (311), a second conductive semiconductor layer (313), and an active layer (312) positioned between the first conductive semiconductor layer (311) and the second conductive semiconductor layer (313). For example, the semiconductor layer (310) may include a first conductive semiconductor layer (311), an active layer (312) positioned on a first surface of the first conductive semiconductor layer (311), and a second conductive semiconductor layer (313) positioned on the active layer (312). The horizontal cross-sectional shape of the semiconductor layer (310) may be any one of a circular, elliptical, or polygonal shape. The light-emitting device (300) according to the first embodiment may have a vertical structure.

[0111] For example, the first conductivity type may be n-type. Accordingly, the second conductivity type may be p-type. Hereinafter, embodiments of the present disclosure will be described based on an example in which the first conductivity type is n-type and the second conductivity type is p-type. For example, the first conductivity type semiconductor layer (311) may be an n-type semiconductor layer and the second conductivity type semiconductor layer (313) may be a p-type semiconductor layer. However, embodiments of the present disclosure are not limited thereto. That is, as another example, the first conductivity type semiconductor layer (311) may be a p-type semiconductor layer and the second conductivity type semiconductor layer (313) may be an n-type semiconductor layer.

[0112] As an exemplary embodiment, the light-emitting element may be a red light-emitting element for emitting red light. Such a red light-emitting element may include a semiconductor of the GaP, GaAs, or InP series. For example, the red light-emitting element may include a compound semiconductor material formed by a combination of at least one of In, Ga, As, and P. However, embodiments of the present disclosure are not limited thereto.

[0113] A light extraction layer (320) may be positioned on the second conductive semiconductor layer (313). This light extraction layer (320) may improve the extraction efficiency of light generated in the semiconductor layer (310). Specifically, light generated in the active layer (312) of the semiconductor layer (310) may be efficiently emitted to the outside of the light-emitting element (300) by the action of the light extraction layer (320).

[0114] Referring to FIGS. 7 to 9, the light extraction layer (320) may include a columnar structure (321) including a plurality of unit columns (323) positioned on a second conductive semiconductor layer (313). The light extraction layer (320) may further include a first conductive layer (322) locally positioned on the unit columns (323).

[0115] Here, the pillar structure (321) may include a third conductivity type semiconductor. For example, the pillar structure (321) may be formed by etching a third conductivity type semiconductor layer (321a; see FIG. 11). For example, the third conductivity type semiconductor or the third conductivity type semiconductor layer (321a) may include the same semiconductor material as the second conductivity type semiconductor layer (313). At this time, the third conductivity type semiconductor or the third conductivity type semiconductor layer (321a) may have a higher doping concentration than the second conductivity type semiconductor layer (313).

[0116] The first conductive layer (322) may be locally positioned at an end of a unit column (323). For example, the first conductive layer (322) may be equal to or smaller than the size of the corresponding unit column (323). Referring to FIG. 8, the first conductive layer (322) may be partially positioned at an upper end of the unit column (323).

[0117] As an exemplary embodiment, the first conductive layer (322) may include a transparent conducting oxide. For example, the first conductive layer (322) may include a conductive oxide material such as ITO (Indium Tin Oxide). However, the present disclosure is not limited thereto, and in addition to ITO, various conductive oxide materials such as ZnO, SnO, and MgO may also be used.

[0118] FIG. 9 shows a FIB (focused ion beam) image showing a state in which a first conductive layer (322) is positioned at an end of a column structure (321) having the same structure as FIG. 8.

[0119] A first conductive layer (322) like this can act as a contact layer (second contact layer) on the semiconductor layer (310). For example, the first conductive layer (322) can act as a contact layer for the second conductive semiconductor layer (313).

[0120] Meanwhile, as an exemplary embodiment, referring to FIG. 10, a second conductive layer (324) may be further positioned on the first conductive layer (322). For example, the second conductive layer (324) may include a transparent conducting oxide. For example, the second conductive layer (324) may include a conductive oxide material such as ITO (Indium Tin Oxide).

[0121] In this way, the second conductive layer (324) may include the same material as the first conductive layer (322). For example, the second conductive layer (324) may be formed of the same material as the first conductive layer (322). The second conductive layer (324) may function as a contact layer (second contact layer) on the semiconductor layer (310) together with the first conductive layer (322).

[0122] As an exemplary embodiment, the second conductive layer (324) may be further positioned on the pillar structure (321). For example, the second conductive layer (324) may have a structure that surrounds the first conductive layer (322) and the upper surface of the pillar structure (321). For example, the second conductive layer (324) may cover most of the area of ​​the upper surface of the light extraction layer (320). For example, the second conductive layer (324) may cover the entire area of ​​the upper surface of the light extraction layer (320).

[0123] Here, the pillar structure (321) may be a structure etched using the first conductive layer (322) as a mask. For example, the pillar structure (321) may be a structure etched using the first conductive layer (322) positioned on the semiconductor layer as an etching mask. This will be described below.

[0124] Referring to FIGS. 8 and 10, the second conductive semiconductor layer (313) and the pillar structure (321) may be formed as a P-type semiconductor layer. For example, the second conductive semiconductor layer (313) and the pillar structure (321) may include P-type GaP.

[0125] As a specific example, the second conductive semiconductor layer (313) may include a P-GaP layer doped with Mg. Meanwhile, the pillar structure (321) may have a higher doping concentration than the second conductive semiconductor layer (313). For example, the pillar structure (321) may include a P-GaP layer heavily doped with C.

[0126] Referring again to FIG. 7, a light-emitting device (300) according to one embodiment of the present disclosure may include a reflective layer (331) positioned on a second surface (lower surface in FIG. 7) of a first conductive semiconductor layer (311).

[0127] Here, the reflective layer (331) may include Au (gold) and Ag (silver). For example, the reflective layer (331) may include an AgAu alloy.

[0128] Meanwhile, the light emitting element (300) may include a first contact layer (332) that is electrically discontinuously connected to at least a portion of the second surface of the first conductive semiconductor layer (311).

[0129] In this way, the light-emitting element (300) may include a metal structure (330) including a reflective layer (331) and a first contact layer (332) on the second surface (lower surface in FIG. 7) of the first conductive semiconductor layer (311).

[0130] In this way, the first contact layer (332) can be electrically connected at least partially to the first conductive semiconductor layer (311). Here, discontinuous or at least partially can mean that the first contact layer (332) is in discontinuous contact at least partially with the lower surface (second surface) of the first conductive semiconductor layer (311) as shown in FIG. 7, i.e., the surface (second surface) facing the reflective layer (331).

[0131] For example, the first contact layer (332) may be positioned so as to partially form an ohmic contact with the first conductive semiconductor layer (311) without covering the entire lower surface (second surface) of the first conductive semiconductor layer (311). In this case, a reflective layer (331) is positioned on the lower surface of the first conductive semiconductor layer (311) where the first contact layer (332) is not positioned, so that the reflectivity of the light-emitting element (300) can be maintained without being significantly reduced by the first contact layer (332).

[0132] As an exemplary embodiment, the first contact layer (332) may occupy an area of ​​5 to 20% of the total area of ​​the lower surface (second surface) of the first conductive semiconductor layer (311).

[0133] The portion where the first contact layer (332) forms an ohmic contact with the first conductive semiconductor layer (311) may be a portion of the first contact layer (332) that has been diffused into the first conductive semiconductor layer (311).

[0134] As an exemplary embodiment, the first contact layer (332) may include a first metal forming an ohmic contact with the first conductive semiconductor layer (311) and a second metal for diffusing the first metal. For example, the first metal and the second metal may form an alloy.

[0135] In this way, the first metal forming the first contact layer (332) may include a region (diffusion region) diffused into the first conductive semiconductor layer (311).

[0136] For example, the first metal may include Ge, and the second metal may include Au. For example, the first contact layer (332) may form an alloy of gold (Au) and germanium (Ge). In other words, the first contact layer (332) may include an AuGe material.

[0137] Here, Ge can diffuse into the first conductive semiconductor layer (311) to form an ohmic contact with the first conductive semiconductor layer (311). Au can help Ge to spread evenly on the second surface without agglomerating.

[0138] As an exemplary embodiment, an interface may exist between the first contact layer (332) and the reflective layer (331). For example, the first contact layer (332) and the reflective layer (331) may exist as separate layers without forming an alloy.

[0139] In this way, the first contact layer (332) may be positioned in a relatively inner region of the lower surface of the first conductive semiconductor layer (311), and the reflective layer (331) may be positioned in a relatively outer region.

[0140] As an exemplary embodiment, although not shown separately, the metal structure (330) of the light-emitting element (300) according to one embodiment of the present disclosure may further include a magnetic layer.

[0141] In order to be used as a subpixel of a display device, the light-emitting element (300) may be assembled using magnetism onto a wiring board (500; see FIG. 27) or a wiring board (400; see FIG. 26) that serves as an assembly board. For example, the light-emitting element (300) may be assembled using magnetism in a fluid phase. Accordingly, the magnetic layer may assist the process of assembling the light-emitting element (300) according to magnetism. A detailed description thereof will be omitted.

[0142] Meanwhile, as described above, the first conductive layer (322) or the first conductive layer (332) and the second conductive layer (324) may function as a second contact layer. An electrode pad (340) may be provided on the second contact layer.

[0143] The light emitting element (300) may include a passivation layer (350) that protects the side surface of the semiconductor layer (310) and the light extraction layer (320).

[0144]

[0145] FIGS. 11 and 12 are cross-sectional views illustrating a manufacturing process of a light-emitting device according to an embodiment of the present disclosure. FIGS. 13 to 18 are photographs illustrating a manufacturing process of a light-emitting device according to an embodiment of the present disclosure.

[0146] FIG. 11 and FIG. 12 mainly show a portion where a light extraction layer (320) is formed on a semiconductor layer (310; see FIG. 7) of a light-emitting element (300). Referring to FIG. 12 and FIG. 13, a manufacturing process of a light-emitting element including a semiconductor layer (310) including a first conductive semiconductor layer (311), a second conductive semiconductor layer (313), a third conductive semiconductor layer (321a), and an active layer (312) positioned between the first conductive semiconductor layer (311) and the second conductive semiconductor layer (313) is shown.

[0147] First, referring to FIG. 11, a planarized first conductive layer (322a) may be formed on a third conductive semiconductor layer (321a). This first conductive layer (322a) may be formed on the third conductive semiconductor layer (321a) to a thickness of several tens to several hundreds of nm. As an exemplary embodiment, this first conductive layer (322a) may be ITO. This ITO may be formed using an e-beam deposition method or a sputter deposition method. When forming ITO using a sputter deposition method, an additional crystallization process may be required. Through this crystallization process, the etching selectivity with respect to the third conductive semiconductor layer (321a) may be improved.

[0148] Thereafter, referring to FIG. 12, the flattened first conductive layer (322a) may be etched to form a mask layer (322b). This mask layer (322b) may include a random mask (322c) having a grain shape. For example, the first conductive layer (322a) may be wet etched to form a mask layer (322b) including a random mask (322c).

[0149] Figures 13 and 14 respectively show scanning electron microscope photographs showing a state in which a mask layer (322b; ITO) is formed on a third conductive semiconductor layer (321a; P-GaP). Here, Figure 13 shows a planar photograph of the etched surface, and Figure 14 is a photograph of the etched surface viewed at an oblique angle.

[0150] Here, as an etchant used in wet etching, hydrochloric acid, nitric acid, oxalic acid, iron chloride series reagent or TE-100 can be used singly or in combination, and it is also possible to use it by increasing the temperature of the solution.

[0151] Next, the third conductive semiconductor layer (321a) can be etched using this mask layer (322b). In this way, the third conductive semiconductor layer (321a) can be etched using the etched first conductive layer (322c) as a mask to form a light extraction layer (320; see FIG. 7). Here, the light extraction layer (320) can include a pillar structure (321) including a plurality of unit pillars (323). Hereinafter, a redundant description of the light extraction layer (320) is omitted.

[0152] In this way, a column structure (321) including a plurality of unit columns (323) can be formed by dry etching the third challenge type semiconductor layer (321a).

[0153] At this time, dry etching can be performed to a desired depth using a single or mixed plasma such as CF4, Ar, Bcl3, SiCl4, O2, etc. At this time, a portion of the thickness of the third conductive semiconductor layer (321a) can be maintained in a planarized state for low operating voltage and current spreading.

[0154] Here, the etching depth may be 40 nm or more. This may correspond to the minimum depth that can be contributed to the light extraction layer (320). The maximum etching depth may be smaller than the maximum thickness of the third conductive semiconductor layer (321a).

[0155] Figures 15 and 16 show a state in which the third conductive semiconductor layer (321a) is etched to a depth of 200 nm. Here, Figure 15 shows a planar photograph of the etched surface, and Figure 16 shows a photograph of the etched surface viewed at an oblique angle.

[0156] Meanwhile, FIGS. 17 and 18 show a state in which the third conductive semiconductor layer (321a) is etched to a depth of 450 nm. Here, FIG. 17 shows a planar photograph of the etched surface, and FIG. 18 shows a photograph of the etched surface viewed at an oblique angle.

[0157] In this way, it can be seen that a rough surface that can function as a light extraction layer (320) is formed by etching. At this time, it can be seen that the size of the roughness is formed to be 1 ㎛ or less.

[0158]

[0159] Figures 19 and 20 are photographs showing changes in the first conductive layer as the etching time increases.

[0160] In Figures 19 and 20, (a) is an optical microscope photograph, and (b) is a scanning electron microscope photograph.

[0161] The case of Fig. 20 shows a state in which the flattened first conductive layer (322a) is wet-etched for a longer period of time than that of Fig. 19.

[0162] As a result of observing the color change of the etched surface through an optical microscope, it can be confirmed that the colors are different in the cases of Figs. 19 and 20. In this way, the visual depth can be predicted when etching is performed later through the color change of the etched surface.

[0163] For example, the shape and depth of a random mask (322c) can be predicted depending on factors such as the concentration of etchant and processing time.

[0164]

[0165] Figures 21 to 23 are photographs showing changes in the etching time of the third conductive semiconductor layer as it increases.

[0166] In Figures 21 to 23, (a) is an optical microscope photograph, and (b) is a scanning electron microscope photograph.

[0167] Figure 21 shows a state in which the etching depth has been increased to 150 nm, and Figure 22 shows a state in which the etching depth has been increased to 170 nm. In addition, Figure 23 shows a state in which the etching depth has been increased to 230 nm.

[0168] As in the case of wet etching the flattened first conductive layer (322a) described above, when the color change of the etched surface is confirmed through an optical microscope, it can be confirmed that the colors are different in the cases of FIGS. 21 to 23. In this way, the visual depth can be predicted when etching is performed later through the color change of the etched surface.

[0169] For example, the shape and depth of surface roughness over time of dry etching can be controlled by changing the color of the etched surface.

[0170]

[0171] Fig. 24 is a cross-sectional view showing a light-emitting element according to the second embodiment of the present disclosure.

[0172] Referring to FIG. 24, the light-emitting device (301) according to the present embodiment may include a semiconductor layer (310) including a first conductive semiconductor layer (314), a second conductive semiconductor layer (316), and an active layer (315) positioned between the first conductive semiconductor layer (314) and the second conductive semiconductor layer (316). For example, the semiconductor layer (310) may include a first conductive semiconductor layer (314), an active layer (315) positioned on a first surface of the first conductive semiconductor layer (314), and a second conductive semiconductor layer (316) positioned on the active layer (315). The horizontal cross-sectional shape of the semiconductor layer (310) may be any one of a circular, elliptical, or polygonal shape. The light-emitting device (301) according to the second embodiment may have a horizontal structure.

[0173] For example, the first conductivity type may be n-type. Accordingly, the second conductivity type may be p-type. For example, the first conductivity type semiconductor layer (314) may be an n-type semiconductor layer and the second conductivity type semiconductor layer (316) may be a p-type semiconductor layer. However, the embodiments of the present disclosure are not limited thereto.

[0174] As an exemplary embodiment, the light-emitting element (301) may be a red light-emitting element for emitting red light. Such a red light-emitting element may include a semiconductor of the GaP, GaAs, or InP series. For example, the red light-emitting element may include a compound semiconductor material formed by a combination of at least one of In, Ga, As, and P. However, the embodiments of the present disclosure are not limited thereto.

[0175] A light extraction layer (320) may be positioned on the second conductive semiconductor layer (316). This light extraction layer (320) may improve the extraction efficiency of light generated in the semiconductor layer (310). Specifically, light generated in the active layer (312) of the semiconductor layer (310) may be efficiently emitted to the outside of the light-emitting element (301) by the action of the light extraction layer (320).

[0176] This light extraction layer (320) may include a columnar structure (321) including a plurality of unit columns (323) positioned on a second conductive semiconductor layer (316). The light extraction layer (320) may further include a first conductive layer (322) locally positioned on the unit columns (323).

[0177] The first conductive layer (322) may be locally positioned at an end of a unit column (323). For example, the first conductive layer (322) may be equal to or smaller than the size of the corresponding unit column (323). For example, the first conductive layer (322) may be partially positioned at an upper end of the unit column (323). Meanwhile, a second conductive layer (324) may be further provided on the first conductive layer (322) (see FIG. 10).

[0178] As described above, the first conductive layer (322) or the first conductive layer (332) and the second conductive layer (324) can act as a second contact layer. An electrode pad (340; first electrode pad) can be provided on the second contact layer.

[0179] The light-emitting element (301) may include a metal structure (330) including a reflective layer (331) and a first contact layer (332) on the second surface (lower surface in FIG. 24) of the first conductive semiconductor layer (314).

[0180] In this way, the first contact layer (332) can be at least partially electrically connected to the first conductive semiconductor layer (314).

[0181] For example, the first contact layer (332) may be positioned to partially form an ohmic contact with the first conductive semiconductor layer (314) without covering the entire lower surface of the first conductive semiconductor layer (314). At this time, a reflective layer (331) is positioned on the lower surface of the first conductive semiconductor layer (314) where the first contact layer (332) is not positioned, so that the reflectivity of the light-emitting element (301) can be maintained without being significantly reduced by the first contact layer (332).

[0182] Meanwhile, a contact layer (341) forming an additional ohmic contact may be provided on a surface where a portion of the upper surface of the first conductive semiconductor layer (314) is exposed. This contact layer (341) may form a second electrode pad.

[0183] The light emitting element (301) may include a passivation layer (350) that protects the side surface of the semiconductor layer (310) and the light extraction layer (320).

[0184] For any other parts not described, the description of the first embodiment described above can be applied equally.

[0185]

[0186] Fig. 25 is a cross-sectional view showing a light-emitting element according to a third embodiment of the present disclosure.

[0187] Referring to FIG. 25, the light-emitting device (302) according to the present embodiment may include a semiconductor layer (310) including a first conductive semiconductor layer (314), a second conductive semiconductor layer (316), and an active layer (315) positioned between the first conductive semiconductor layer (314) and the second conductive semiconductor layer (316). For example, the semiconductor layer (310) may include a first conductive semiconductor layer (314), an active layer (315) positioned on a first surface of the first conductive semiconductor layer (314), and a second conductive semiconductor layer (316) positioned on the active layer (315). The horizontal cross-sectional shape of the semiconductor layer (310) may be any one of a circular, oval, or polygonal shape. The light-emitting device (302) according to the third embodiment may have a horizontal structure.

[0188] A light extraction layer (320) may be positioned on the second conductive semiconductor layer (316). This light extraction layer (320) may improve the extraction efficiency of light generated in the semiconductor layer (310). Specifically, light generated in the active layer (312) of the semiconductor layer (310) may be efficiently emitted to the outside of the light-emitting element (301) by the action of the light extraction layer (320).

[0189] This light extraction layer (320) may include a columnar structure (321) including a plurality of unit columns (323) positioned on a second conductive semiconductor layer (316). The light extraction layer (320) may further include a first conductive layer (322) locally positioned on the unit columns (323).

[0190] The first conductive layer (322) may be locally positioned at an end of a unit column (323). For example, the first conductive layer (322) may be equal to or smaller than the size of the corresponding unit column (323). For example, the first conductive layer (322) may be partially positioned at an upper end of the unit column (323). Meanwhile, a second conductive layer (324) may be further provided on the first conductive layer (322) (see FIG. 10).

[0191] The first conductive layer (322) or the first conductive layer (332) and the second conductive layer (324) may function as a second contact layer. An electrode pad (340; first electrode pad) may be provided on the second contact layer.

[0192] The light emitting element (302) may include a metal structure (330) including a reflective layer (331) on the second surface (lower surface in FIG. 25) of the first conductive semiconductor layer (314).

[0193] Meanwhile, a contact layer (341) forming an ohmic contact may be provided on a surface where a portion of the upper surface of the first conductive semiconductor layer (314) is exposed. This contact layer (341) may form a second electrode pad.

[0194] The light emitting element (302) may include a passivation layer (350) that protects the side surface of the semiconductor layer (310) and the light extraction layer (320).

[0195] For any other parts not described, the description of the second embodiment described above can be applied equally.

[0196]

[0197] Fig. 26 is a cross-sectional view showing a display device according to one embodiment of the present disclosure.

[0198] Referring to FIG. 26, a display device (10) according to the present embodiment can be configured by arranging light-emitting elements (300R, 300G, 300B) forming unit subpixels on a wiring board (400) on which first electrodes (410) are arranged.

[0199] A plurality of first electrodes (410) may be positioned on a wiring board (400). These first electrodes (410) may include a pair of assembled electrodes (411, 412) described above. These first electrodes (410) may be used as wiring electrodes after light-emitting elements (300R, 300G, 300B) are assembled. The first electrodes (410) may be positioned in sections on the wiring board (400). Here, the first electrodes (410) may be used as data electrodes (pixel electrodes) or scan electrodes (common electrodes).

[0200] In Fig. 26, three light-emitting elements (300R, 300G, 300B) can constitute a unit pixel. At this time, a red light-emitting element (300R) that emits red light, a green light-emitting element (300G) that emits green light, and a blue light-emitting element (300B) that emits blue light can be included. These unit pixels can be repeatedly provided on a wiring board (400).

[0201] Figure 26 illustrates three light-emitting elements (300R, 300G, 300B) having the form of the light-emitting element (300) according to the first embodiment described above.

[0202] Although not shown, the first electrode (410) arranged on the wiring board (400) may be connected to a TFT layer equipped with a thin film transistor (TFT). A data electrode (pixel electrode) may be connected to this TFT layer. A detailed description thereof is omitted.

[0203] As an exemplary embodiment, at least one of the upper and lower surfaces of the light-emitting element (300R, 300G, 300B) may be circular. For example, the light-emitting element (300R, 300G, 300B) may have a cylindrical shape or a truncated cone shape.

[0204] In order to provide up-down selectivity when assembling the light-emitting elements (300R, 300G, 300B), the lower area of ​​the light-emitting elements (300R, 300G, 300B) may be larger than the upper area. For example, the area of ​​the surface close to the first contact layer (331) of the light-emitting elements (300R, 300G, 300B) may be larger than the area of ​​the surface far from the first contact layer (331).

[0205] Meanwhile, an organic barrier wall (421) may be positioned between the light-emitting element (300R, 300G, 300B) and the first electrode (410). The reflective layer (331) and the first contact layer (332) of the light-emitting element (300R, 300G, 300B) may be insulated by the organic barrier wall (421).

[0206] Additionally, the display device (10) may include a first connection electrode (430) that electrically connects one side of the first electrode (410) and the light-emitting element (300R, 300G, 300B). This first connection electrode (430) may be made of a metal with high electrical conductivity, such as Al, Mo, Cu, Ag, or Pt.

[0207] As an exemplary embodiment, one side of the light-emitting element (300R, 300G, 300B) to which the first connecting electrode (430) is connected may be a side surface with respect to the light-emitting layer (active layer; 312) of the light-emitting element (300R, 300G, 300B). For example, the first connecting electrode (430) may be connected laterally with respect to a surface formed by the light-emitting layer (312) of the light-emitting element (300R, 300G, 300B). The first connecting electrode (430) may extend laterally to the side surface of the first conductive semiconductor layer (311) of the light-emitting element (300R, 300G, 300B) and be electrically connected to the first conductive semiconductor layer (311).

[0208] At this time, the aluminum (Al) used as the first connecting electrode (430) and the reflective layer (332) of the light-emitting element (300R, 300G, 300B) can form an alloy. By forming this alloy, the thermal / electrical characteristics of the light-emitting element and the display device can be improved.

[0209] Referring to Fig. 26, the first connecting electrode (430) may be provided on both sides of the light-emitting element (300R, 300G, 300B). In some cases, the first connecting electrode (430) may be provided to cover the side of the light-emitting element (300R, 300G, 300B).

[0210] A planarization layer (420) may be positioned on the side of the first connecting electrode (430) and the light-emitting element (300R, 300G, 300B). The planarization layer (420) may cover the first connecting electrode (430) and the light-emitting element (300R, 300G, 300B). The planarization layer (420) may have a height corresponding to the upper side of the light-emitting element (300R, 300G, 300B), or may be provided at a higher height.

[0211] A second connection electrode (440) may be positioned on the flattening layer (420) and electrically connected to the other side of the light-emitting element (300R, 300G, 300B). For example, the second connection electrode (440) may include a transparent electrode such as ITO. Accordingly, light emitted from the light-emitting element (300R, 300G, 300B) may pass through the second connection electrode (440) and be emitted to the outside.

[0212] Referring to FIG. 26, the second connecting electrode (440) may be partially positioned on the light emitting element (300R, 300G, 300B). In some cases, these second connecting electrodes (440) may be connected to each other by an additional second electrode (not shown).

[0213]

[0214] Fig. 27 is a cross-sectional view showing a display device according to another embodiment of the present disclosure.

[0215] Referring to FIG. 27, a display device (10) according to the present embodiment can be configured by arranging light-emitting elements (300R, 300G, 300B) forming unit subpixels on a wiring board (500) on which first electrodes (510) are arranged.

[0216] A plurality of first electrodes (510) may be positioned on a wiring board (500). These first electrodes (510) may be used as wiring electrodes. The first electrodes (510) may be positioned in sections on the wiring board (500). Here, the wiring electrodes may be used as data electrodes (pixel electrodes) or scan electrodes (common electrodes).

[0217] In Fig. 27, three light-emitting elements (300R, 300G, 300B) can constitute a unit pixel. At this time, a red light-emitting element (300R) that emits red light, a green light-emitting element (300G) that emits green light, and a blue light-emitting element (300B) that emits blue light can be included. These unit pixels can be repeatedly provided on a wiring board (500).

[0218] Figure 27 illustrates three light-emitting elements (300R, 300G, 300B) having the form of the light-emitting element (300) according to the first embodiment described above.

[0219] Although not shown, the first electrode (510) arranged on the wiring board (500) may be connected to a TFT layer equipped with a thin film transistor (TFT). A data electrode (pixel electrode) may be connected to this TFT layer. A detailed description thereof is omitted.

[0220] As an exemplary embodiment, at least one of the upper and lower surfaces of the light-emitting element (300R, 300G, 300B) may be circular. For example, the light-emitting element (300R, 300G, 300B) may have a cylindrical shape or a truncated cone shape.

[0221] In order to provide up-down selectivity when assembling the light-emitting elements (300R, 300G, 300B), the lower area of ​​the light-emitting elements (300R, 300G, 300B) may be larger than the upper area. For example, the area of ​​the surface close to the first contact layer (331) of the light-emitting elements (300R, 300G, 300B) may be larger than the area of ​​the surface far from the first contact layer (331).

[0222] Meanwhile, an organic barrier wall (521) may be positioned between the light-emitting element (300R, 300G, 300B) and the first electrode (510). The reflective layer (331) and the first contact layer (332) of the light-emitting element (300R, 300G, 300B) may be insulated by the organic barrier wall (521).

[0223] Additionally, the display device (10) may include a first connection electrode (530) that electrically connects one side of the first electrode (510) and the light-emitting element (300R, 300G, 300B). This first connection electrode (530) may be made of a metal with high electrical conductivity, such as Al, Mo, Cu, Ag, or Pt.

[0224] As an exemplary embodiment, one side of the light-emitting element (300R, 300G, 300B) to which the first connecting electrode (530) is connected may be a side surface with respect to the light-emitting layer (active layer; 312) of the light-emitting element (300R, 300G, 300B). For example, the first connecting electrode (530) may be connected laterally with respect to a surface formed by the light-emitting layer (312) of the light-emitting element (300R, 300G, 300B). The first connecting electrode (530) may extend laterally to the side surface of the first conductive semiconductor layer (311) of the light-emitting element (300R, 300G, 300B) and be electrically connected to the first conductive semiconductor layer (311).

[0225] At this time, the aluminum (Al) used as the first connecting electrode (530) and the reflective layer (332) of the light-emitting element (300R, 300G, 300B) can form an alloy. By forming this alloy, the thermal / electrical characteristics of the light-emitting element and the display device can be improved.

[0226] Referring to Fig. 27, the first connecting electrode (530) may be provided on both sides of the light-emitting element (300R, 300G, 300B). In some cases, the first connecting electrode (530) may be provided to cover the side of the light-emitting element (300R, 300G, 300B).

[0227] A planarization layer (520) may be positioned on the side of the first connecting electrode (530) and the light-emitting element (300R, 300G, 300B). The planarization layer (520) may cover the first connecting electrode (530) and the light-emitting element (300R, 300G, 300B). The planarization layer (520) may have a height corresponding to the upper side of the light-emitting element (300R, 300G, 300B), or may be provided at a higher height.

[0228] A second connection electrode (540) may be positioned on the planarization layer (520) and electrically connected to the other side of the light-emitting element (300R, 300G, 300B). For example, the second connection electrode (540) may include a transparent electrode such as ITO. Accordingly, light emitted from the light-emitting element (300R, 300G, 300B) may pass through the second connection electrode (540) and be emitted to the outside.

[0229] Referring to FIG. 27, the second connecting electrode (540) may be partially positioned on the light emitting element (300R, 300G, 300B). In some cases, these second connecting electrodes (540) may be connected to each other by an additional second electrode (not shown).

[0230]

[0231] According to the embodiments of the present disclosure, the light extraction structure of the light emitting element (300, 301, 302) can be efficiently implemented through the light extraction layer (320), thereby improving the light extraction efficiency of the light emitting element (300, 301, 302).

[0232] In addition, along with improving the light extraction efficiency of the light emitting elements (300, 301, 302), when the light emitting elements (300, 301, 302) are used as display pixels, the efficiency of the display device (10) can be improved together.

[0233] In addition, the phenomenon of the color viewing angle of the display device (10) becoming uneven depending on the light emitting element (300, 301, 302) can be improved.

[0234]

[0235] The above description is merely an example of the technical idea of ​​the present disclosure, and those skilled in the art to which the present disclosure pertains will be able to make various modifications and variations without departing from the essential characteristics of the present disclosure.

[0236] Accordingly, the embodiments disclosed in the present disclosure are intended to illustrate rather than limit the technical idea of ​​the present disclosure, and the scope of the technical idea of ​​the present disclosure is not limited by these embodiments.

[0237] The scope of protection of the present disclosure should be interpreted by the claims below, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the rights of the present disclosure.

[0238] According to the present disclosure, a semiconductor light-emitting element such as a micro LED and a display device using the same can be provided.

Claims

1. First challenge type semiconductor layer; An active layer positioned on the first surface of the first conductive semiconductor layer; A second conductive semiconductor layer positioned on the active layer; A reflective layer positioned on the second surface of the first conductive semiconductor layer; and Including a light extraction layer positioned on the second conductive semiconductor layer, The above light extraction layer is, A column structure including a plurality of unit columns positioned on the first conductive semiconductor layer; and A first conductive layer comprising a first conductive layer locally positioned on the unit column. Light-emitting element.

2. In the first paragraph, the pillar structure includes a third conductive semiconductor. Light-emitting element.

3. In the second paragraph, the third conductive semiconductor includes the same semiconductor material as the second conductive semiconductor layer. Light-emitting element.

4. In the first paragraph, the first conductive layer includes a transparent conductive oxide. Light-emitting element.

5. In the first paragraph, the first conductive layer further comprises a second conductive layer positioned on the first conductive layer. Light-emitting element.

6. In the fifth paragraph, the second conductive layer is further positioned on the pillar structure. Light-emitting element.

7. In the fifth paragraph, the second conductive layer includes a transparent conductive oxide. Light-emitting element.

8. In the first paragraph, the pillar structure is a structure etched using the first conductive layer as a mask. Light-emitting element.

9. In the first paragraph, at least a portion of the first contact layer is further electrically connected discontinuously to the second surface of the first conductive semiconductor layer. Light-emitting element.

10. In the 9th paragraph, the first contact layer forms an ohmic contact with the first conductive semiconductor layer at a portion that is electrically connected discontinuously to the second surface. Light-emitting element.

11. In the first paragraph, the first conductive layer functions as a second contact layer for the second conductive semiconductor layer. Light-emitting element.

12. A method for manufacturing a light-emitting device comprising a semiconductor layer including a first conductive semiconductor layer, a second conductive semiconductor layer, a third conductive semiconductor layer, and an active layer positioned between the first conductive semiconductor layer and the second conductive semiconductor layer, A step of forming a first conductive layer on the third conductive semiconductor layer; a step of etching the first conductive layer; and A step of forming a light extraction layer including a columnar structure including a plurality of unit columns by etching the third conductive semiconductor layer using the first conductive layer as a mask. Method for manufacturing a light emitting device.

13. In the 12th paragraph, the first conductive layer includes a transparent conductive oxide. Method for manufacturing a light emitting device.

14. In the 12th paragraph, further comprising a step of forming a second conductive layer on the first conductive layer and the pillar structure. Method for manufacturing a light emitting device.

15. In a display device using a light-emitting element, A wiring board having a first electrode arranged thereon; A light emitting element including a semiconductor layer arranged on the above wiring board to form a unit subpixel; A first connection electrode electrically connecting one side of the semiconductor layer of the first electrode and the light-emitting element; A planarizing layer covering the light-emitting element and the first connecting electrode; and It is configured to include a second connection electrode positioned on the above-mentioned flattening layer and electrically connected to the other side of the semiconductor layer of the light-emitting element, The above light emitting element, A light extraction layer is included, positioned on the semiconductor layer, The above light extraction layer is, A column structure including a plurality of unit columns positioned on the semiconductor layer; and A first conductive layer comprising a first conductive layer locally positioned on the unit column. Display device.

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