Light-emitting device and display apparatus using same

Abstract

A light-emitting device according to an embodiment of the present disclosure may comprise: a first conductive semiconductor layer; an active layer located on a first surface of the first conductive semiconductor layer; a second conductive semiconductor layer positioned on the active layer; a first contact layer positioned on a second surface of the first conductive semiconductor layer; and a second contact layer positioned on the first conductive semiconductor layer, wherein the first contact layer includes a first structural layer having reflective properties, and the first structural layer includes: a first layer in which gold (Au) and silver (Ag) are mixed; and a second layer positioned between the first layer and the second conductive semiconductor layer and containing In.

Description

Light-emitting element and display device using the same

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

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

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

[0004] Meanwhile, light-emitting diodes (LEDs) are semiconductor light-emitting devices well known for converting electric current into light. Starting with the commercialization of red LEDs using GaAsP compound semiconductors in 1962, they have been used as light sources for display images in electronic devices, including information and communication equipment, along with GaP:N-based green LEDs. Therefore, a solution to the aforementioned problems can be proposed by implementing a display using semiconductor light-emitting devices. The above-mentioned semiconductor light-emitting devices have various advantages over filament-based light-emitting devices, such as a long lifespan, low power consumption, excellent initial driving characteristics, and high vibration resistance.

[0005] To improve the light extraction efficiency and optical characteristics of such light-emitting devices, a reflective film can be used on the top or bottom of the light-emitting device.

[0006] As light-emitting elements are used as pixels in display devices, their size is gradually shrinking, and millimeter-sized mini LEDs or micrometer-sized micro LEDs are being used.

[0007] As the size of Micro LEDs is reduced, their luminous efficiency can decrease exponentially. To compensate for this, the characteristics of the reflective film, which reflects light emitted in all directions from the active layer (Multi-Quantum Well) upwards, need to be improved.

[0008] In the display manufacturing process, micro LEDs may require resistance to fluids. In such cases, a reflective film can be fabricated using a metal material that takes into account the electrical and chemical properties of the electrode (possessing resistance to fluid dispersion solutions).

[0009] Such reflective films may be required to exhibit excellent electrical, chemical, and optical properties.

[0010] The technical problem to be solved by the present disclosure is to provide a light-emitting element that provides a reflective layer in the form of a gold (Au)-silver (Ag) mixture that is not affected by a fluid dispersion solution for the self-assembly of the light-emitting element, and a display device using the same.

[0011] In addition, the technical problem to be solved by the present disclosure is to provide a light-emitting element capable of lowering contact resistance while including a reflective layer in the form of a gold (Au)-silver (Ag) mixture, and a display device using the same.

[0012] In addition, the technical problem to be solved by the present disclosure is to provide a light-emitting element and a display device using the same that can improve reliability or productivity by combining such a reflective layer and an ohmic layer.

[0013] Furthermore, the objective of one embodiment of the present invention is to solve various problems not mentioned herein. Those skilled in the art will understand this from the full context of the specification and drawings.

[0014] A light-emitting element according to the first aspect of the present disclosure for achieving the above objective comprises: a first conductivity-type semiconductor layer; an active layer located on a first surface of the first conductivity-type semiconductor layer; a second conductivity-type semiconductor layer located on the active layer; a first contact layer located on a second surface of the first conductivity-type semiconductor layer; and a second contact layer located on the first conductivity-type semiconductor layer, wherein the first contact layer comprises a first structural layer having reflective properties, and the first structural layer may comprise a first layer mixed with gold (Au) and silver (Ag); and a second layer located between the first layer and the second conductivity-type semiconductor layer and comprising In.

[0015] A light-emitting element according to a second aspect of the present disclosure for achieving the above objective comprises: a first conductivity-type semiconductor layer; an active layer located on a first surface of the first conductivity-type semiconductor layer; a second conductivity-type semiconductor layer located on the active layer; a first contact layer located on a second surface of the first conductivity-type semiconductor layer; and a second contact layer located on the second conductivity-type semiconductor layer, wherein the first contact layer comprises a first structural layer having reflective properties, and the first structural layer may comprise an ohmic layer comprising InN in contact with the first conductivity-type semiconductor layer; and a reflective layer located on the ohmic layer and mixed with gold (Au) and silver (Ag).

[0016] A display device according to an embodiment of the present disclosure for achieving the above objective comprises: a wiring substrate having a first electrode arranged thereon; a light-emitting element comprising a semiconductor layer disposed on the wiring substrate and forming a unit subpixel; a first connecting electrode electrically connecting the first electrode and one side of the semiconductor layer of the light-emitting element; a planarization layer covering the light-emitting element and the first connecting electrode; and a second connecting electrode located 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 comprises a first contact layer located on a first surface of the semiconductor layer; and a second contact layer located on a second surface of the semiconductor layer, wherein the first contact layer comprises a first structural layer having reflective properties, and the first structural layer may comprise a first layer mixed with gold (Au) and silver (Ag); and a second layer located between the first layer and the first conductive semiconductor layer and comprising In.

[0017] According to embodiments of the present disclosure, a reflective layer in the form of a gold (Au)-silver (Ag) mixture that is not affected by a fluid dispersion solution for self-assembly of a light-emitting element can be provided to improve reflective characteristics and reliability.

[0018] Due to the high work function of silver (Ag) and gold (Au), the nitride semiconductor (e.g., GaN) thin film forming the semiconductor layer and the reflective layer have high contact resistance, which can result in a relatively high driving voltage. Accordingly, according to the embodiments of the present disclosure, the contact resistance can be lowered by providing an ohmic layer containing indium. In addition, the gold (Au) and silver (Ag) can be evenly mixed to improve reflectivity.

[0019] Meanwhile, according to the embodiments of the present disclosure, a structural layer that can improve reliability or productivity by combining such a reflective layer and an ohmic layer can be provided.

[0020] Accordingly, the light extraction efficiency of a vertical micro LED can be significantly improved by applying a contact structure that has high reflectivity and is not affected by the dispersion process, which is a process performed in self-assembled light-emitting devices.

[0021] Furthermore, according to another embodiment of the present disclosure, there are additional technical effects not mentioned herein. Those skilled in the art will understand this from the full context of the specification and drawings.

[0022] FIG. 1 is an exemplary diagram of a living room of a house in which a display device according to an embodiment is placed.

[0023] FIG. 2 is a block diagram schematically showing a display device according to an embodiment.

[0024] Figure 3 is a circuit diagram showing an example of a pixel of Figure 2.

[0025] Figure 4 is an enlarged view of the first panel area of ​​the display device of Figure 1.

[0026] Figure 5 is a cross-sectional view along the line B1-B2 in area A2 of Figure 4.

[0027] FIG. 6 is an example diagram showing how a light-emitting element according to an embodiment is assembled onto a substrate by a self-assembly method.

[0028] FIG. 7 is a cross-sectional view showing a light-emitting element according to a first embodiment of the present disclosure.

[0029] FIG. 8 is a graph showing the components of the ohmic layer of a light-emitting element before and after heat treatment according to embodiments of the present disclosure.

[0030] FIG. 9 is a cross-sectional view showing a light-emitting element according to a second embodiment of the present disclosure.

[0031] FIG. 10 is a photograph mainly showing the first contact layer portion of a light-emitting element according to the second embodiment of the present disclosure.

[0032] FIG. 11 is a graph showing the reflectance of a first structural layer of a light-emitting element according to embodiments of the present disclosure.

[0033] FIG. 12 is a graph showing the driving voltage of a light-emitting element according to embodiments of the present disclosure.

[0034] FIG. 13 is a cross-sectional view showing a light-emitting element according to a third embodiment of the present disclosure.

[0035] FIG. 14 is a cross-sectional view showing a display device having a light-emitting element according to embodiments of the present disclosure.

[0036] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components, regardless of drawing symbols, are assigned the same reference number, and redundant descriptions thereof will be omitted. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not inherently possess distinct meanings or roles. Furthermore, when describing the embodiments disclosed in this specification, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions could obscure the essence of the embodiments disclosed in this specification. Additionally, it should be noted that the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification and should not be interpreted as limiting the technical concept disclosed in this specification.

[0037] Furthermore, for the convenience of explanation, each drawing is described, but it is also within the scope of the present invention that a person skilled in the art combines at least two drawings to implement other embodiments.

[0038] Furthermore, when elements such as layers, regions, or substrates are referred to as existing "on" other components, it can be understood that this means they exist directly on the other elements or that there may be an intermediate element between them.

[0039] The concept of a display device as described in this specification includes all display devices that display information as a unit pixel or a set of unit pixels. Therefore, it is not limited to finished products but can also be applied to components. For example, a panel corresponding to a component of a digital TV also independently corresponds to a display device as defined in this specification. Finished products may include mobile phones, smartphones, laptop computers, digital broadcasting terminals, PDAs (personal digital assistants), PMPs (portable multimedia players), navigation systems, Slate PCs, Tablet PCs, Ultra Books, digital TVs, desktop computers, etc.

[0040] However, those skilled in the art will readily understand that the configuration according to the embodiments described in this specification may be applied to displayable devices, even in the form of new products developed in the future.

[0041] The semiconductor light-emitting device mentioned in this specification is a concept that includes LEDs, micro LEDs, etc., and may be used interchangeably.

[0042]

[0043] FIG. 1 illustrates a living room of a house in which a display device according to one embodiment is placed.

[0044] 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), communicate with each electronic product based on IoT, and control each electronic product based on user setting data.

[0045] The display device (100) according to the embodiment may include a flexible display fabricated 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.

[0046] 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 a light-emitting element. In the embodiments, the light-emitting element may be a Micro-LED or a Nano-LED, but is not limited thereto.

[0047]

[0048] 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.

[0049] Referring to FIGS. 2 and FIGS. 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).

[0050] A display device (100) of one embodiment can drive a light-emitting element using an active matrix (AM) method or a passive matrix (PM) method.

[0051] The driving circuit (20) may include a data driving unit (21) and a timing control unit (22).

[0052] The display panel (10) may be divided into a display area (DA) and a non-display area (NDA) placed 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) may include data lines (D1~Dm, where m is an integer greater than or equal to 2), scan lines (S1~Sn, where n is an integer greater than or equal to 2) that intersect the data lines (D1~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~Dm) and the scan lines (S1~Sn).

[0053] Each of the pixels (PX) may include a first subpixel (PX1), a second subpixel (PX2), and a third subpixel (PX3). The first subpixel (PX1) may emit first color light of a first wavelength, the second subpixel (PX2) may emit second color light of a second wavelength, and the third subpixel (PX3) may emit 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 is not limited thereto. Additionally, FIG. 2 illustrates that each of the pixels (PX) includes three subpixels, but is not limited thereto. That is, each of the pixels (PX) may include four or more subpixels.

[0054] Each of the first subpixel (PX1), the second subpixel (PX2), and the third subpixel (PX3) can be connected to at least one of the data lines (D1~Dm), at least one of the scan lines (S1~Sn), and a high potential voltage line. The first subpixel (PX1) may include light-emitting elements (LDs) as shown in FIG. 3, a plurality of transistors for supplying current to the light-emitting elements (LDs), and at least one capacitor (Cst).

[0055] Although not shown in the drawing, each of the first subpixel (PX1), the second subpixel (PX2), and the third subpixel (PX3) may include only one light-emitting element (LD) and at least one capacitor (Cst).

[0056] Each of the light-emitting elements (LDs) may be a semiconductor light-emitting diode comprising 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 is not limited thereto.

[0057] Referring to FIG. 3, a plurality of transistors may include a driving transistor (DT) that supplies current to light-emitting elements (LDs) and a scan transistor (ST) that supplies a data voltage to the gate electrode of the driving transistor (DT). The driving transistor (DT) may include a gate electrode connected to the 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 the first electrodes of the light-emitting elements (LDs). 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).

[0058] 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).

[0059] The driving transistor (DT) and the scan transistor (ST) can be formed as thin film transistors. Additionally, although FIG. 3 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 electrode and the drain electrode of each of the driving transistor (DT) and the scan transistor (ST) may be changed.

[0060] Additionally, FIG. 3 illustrates that each of the first subpixel (PX1), the second subpixel (PX2), and the third subpixel (PX3) comprises a 2T1C (2 Transistor - 1 Capacitor) having one driving transistor (DT), one scan transistor (ST), and one capacitor (Cst), but the present disclosure is not limited thereto. Each of the first subpixel (PX1), the second subpixel (PX2), and the third subpixel (PX3) may comprise a plurality of scan transistors (ST) and a plurality of capacitors (Cst).

[0061] Referring again to FIG. 2, the driving circuit (20) outputs signals and voltages for driving the display panel (10). To this end, the driving circuit (20) may include a data driving unit (21) and a timing control unit (22).

[0062] The data driver (21) receives digital video data (DATA) and a source control signal (DCS) from the timing control unit (22). The data driver (21) converts the digital video data (DATA) into analog data voltages according to the source control signal (DCS) and supplies them to the data lines (D1~Dm) of the display panel (10).

[0063] The timing control unit (22) receives digital video data (DATA) and timing signals from a 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.

[0064] The scan driver (30) receives a scan control signal (SCS) from the timing control unit (22). The scan driver (30) generates scan signals according to the scan control signal (SCS) and supplies them to the scan lines (S1~Sn) of the display panel (10). The scan driver (30) may be formed in the non-display area (NDA) of the display panel (10) by including a plurality of transistors. Alternatively, the scan driver (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).

[0065] The power supply circuit (50) can generate a high potential voltage (VDD) and a low potential voltage (VSS) from the main power supply to drive the light-emitting elements (LDs) of the display panel (10) 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 from the main power supply to drive the driving circuit (20) and the scan driving unit (30).

[0066]

[0067] FIG. 4 is an enlarged view of the first panel area of ​​the display device of FIG. 1.

[0068] According to FIG. 4, a display device (100) according to one embodiment can be manufactured by mechanically and electrically connecting a plurality of panel regions, such as a first panel region (A1), by tiling.

[0069] The first panel area (A1) may include a plurality of light-emitting elements (150) arranged for each unit pixel (PX in FIG. 2).

[0070] 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 placed in the first sub-pixel (PX1), a plurality of green light-emitting elements (150G) may be placed in the second sub-pixel (PX2), and a plurality of blue light-emitting elements (150B) may be placed in the third sub-pixel (PX3). The unit pixel (PX) may further include a fourth sub-pixel in which no light-emitting elements are placed, but is not limited thereto. Meanwhile, the light-emitting element (150) may be a semiconductor light-emitting element.

[0071]

[0072] Figure 5 is a cross-sectional view along the line B1-B2 in area A2 of Figure 4.

[0073] 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).

[0074] The assembly wiring may include a first assembly wiring (201) and a second assembly wiring (202) spaced apart from each other. The first assembly wiring (201) and the second assembly wiring (202) may be provided to generate a dielectrophoretic force to assemble a light-emitting element (150). Additionally, the first assembly wiring (201) and the second assembly wiring (202) may be electrically connected to the electrodes of the light-emitting element and function as electrodes of a display panel.

[0075] The assembled wiring (201, 202) may be formed of a transparent electrode (ITO) or may include a metallic material with excellent electrical conductivity. For example, the assembled 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.

[0076] A first insulating layer (211a) may be disposed between the first assembled wiring (201) and the second assembled wiring (202), and a second insulating layer (211b) may be disposed on the first assembled wiring (201) and the second assembled wiring (202). The first insulating layer (211a) and the second insulating layer (211b) may be oxide films, nitride films, etc., but are not limited thereto.

[0077] 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 implement red and green by providing a red phosphor and a green phosphor, etc.

[0078] The substrate (200) may be formed of glass or polyimide. Additionally, the substrate (200) may include flexible materials such as PEN (Polyethylene Naphthalate) or PET (Polyethylene Terephthalate). Furthermore, the substrate (200) may be a transparent material, but is not limited thereto.

[0079] The third insulating layer (206) may include a material with insulating and flexible properties such as polyimide, PEN, PET, etc., and may be formed integrally with the substrate (200) to form a single substrate.

[0080] The third insulating layer (206) may be a conductive adhesive layer having adhesiveness and conductivity, and the conductive adhesive layer may be flexible to enable the flexible function of the display device. For example, the third insulating layer (206) may be an anisotropy conductive film (ACF), an anisotropy conductive medium, a solution containing conductive particles, etc. The conductive adhesive layer may be a layer that is electrically conductive in the direction perpendicular to the thickness, but electrically insulating in the direction horizontal to the thickness.

[0081] The third insulating layer (206) may include an assembly hole (203) into which a light-emitting element (150) is inserted (see FIG. 6). Thus, when self-assembling, 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 called an insertion hole, a fixing hole, an alignment hole, etc.

[0082] 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) using an electric field can be fixed more precisely.

[0083] A third insulating layer (206) is formed on the assembled wiring (201, 202) to protect the assembled wiring (201, 202) from fluid (1200) and prevent leakage of current flowing through the assembled 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.

[0084] Additionally, the third insulating layer (206) may include a material with insulating and flexible properties 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 an insulating layer that is adhesive or a conductive adhesive layer that is conductive. The third insulating layer (206) may be flexible so that it can enable the flexible function of the display device.

[0086] The third insulating layer (206) has a partition, and an assembly hole (203) can be formed by this partition. For example, when forming the substrate (200), a portion of the third insulating layer (206) is removed so that each of the light-emitting elements (150) can be assembled in the assembly hole (203) of the third insulating layer (206).

[0087] An assembly hole (203) is formed in the substrate (200) to which light-emitting elements (150) are joined, and the surface on which the assembly hole (203) is formed can come into contact with a fluid (1200). The assembly hole (203) can guide the precise assembly position of the light-emitting elements (150).

[0088] 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 location. Accordingly, it is possible to prevent other light-emitting elements from being assembled in the assembly hole (203) or multiple light-emitting elements from being assembled.

[0089]

[0090] FIG. 6 is a diagram 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 explained with reference to FIG. 6.

[0091] The substrate (200) may be a panel substrate of a display device. In the following description, the substrate (200) is described as being a panel substrate of a display device, but the embodiment is not limited thereto.

[0092] Referring to FIG. 6, a plurality of light-emitting elements (150) can be introduced into a chamber (1300) filled with a fluid (1200). The fluid (1200) may be water, such as ultrapure water, but is not limited thereto. The chamber may be called a water tank, a container, a vessel, etc.

[0093] Afterward, the substrate (200) may be placed on the chamber (1300). According to an embodiment, the substrate (200) may be introduced into the chamber (1300).

[0094] As shown in FIG. 5, a pair of assembly wires (201, 202) corresponding to each of the light-emitting elements (150) to be assembled may be disposed on the substrate (200).

[0095] Referring to FIG. 6, after the substrate (200) is placed, an assembly device (1100) including a magnetic material can move along the substrate (200). For example, a magnet or an electromagnet may be used as the magnetic material. The assembly device (1100) can move while in contact with the substrate (200) to maximize the area where the magnetic field is applied within the fluid (1200).

[0096] According to an embodiment, the assembly device (1100) may include a plurality of magnetic bodies or a magnetic body of a size corresponding to the substrate (200). In this case, the movement distance of the assembly device (1100) may be limited to within a predetermined range.

[0097] Due to the magnetic field generated by the assembly device (1100), the light-emitting element (150) inside the chamber (1300) can move toward the assembly device (1100).

[0098] While moving toward the assembly device (1100), the light-emitting element (150) can enter the assembly hole (203) by means of a dielectrophoretic force (DEP force) and come into contact with the substrate (200).

[0099] Specifically, the assembly wiring (201, 202) forms an electric field by an externally supplied power source, and a dielectrophoretic force can be formed between the assembly wiring (201, 202) by this electric field. By this dielectrophoretic force, a light-emitting element (150) can be fixed to an assembly hole (203) on a substrate (200).

[0100] 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 the embodiment, by the self-assembly method using the electromagnetic field described above, the time required for each light-emitting element (150) to be assembled on the substrate (200) can be drastically shortened, so a large-area high-pixel display can be implemented more quickly and economically.

[0101] 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 wiring, thereby improving the bonding strength of the light-emitting element (150).

[0102] Next, a molding layer (not shown) may be formed in the assembly hole (203) of the substrate (200). The molding layer may be a transparent resin or a resin containing a reflective material or a scattering material.

[0103]

[0104] FIG. 7 is a cross-sectional view showing a light-emitting element according to a first embodiment of the present disclosure.

[0105] Referring to FIG. 7, an example of a light-emitting element (301) having a vertical structure is shown. In FIG. 7, the light-emitting element (301) shows a state in which the light-emitting surface is reversed to the lower side.

[0106] The light-emitting element (301) according to the first embodiment of the present invention may include a semiconductor layer (310) comprising a first conductive semiconductor layer (311), a second conductive semiconductor layer (313), and an active layer (312) located 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) located on a first surface of the first conductive semiconductor layer (311), and a second conductive semiconductor layer (313) located 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.

[0107] 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 focusing on an example where 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.

[0108] As an exemplary embodiment, the light-emitting element (301) may be a blue light-emitting element for emitting blue light. Such a light-emitting element (301) may include a nitride semiconductor. For example, the light-emitting element (301) may include a gallium nitride (GaN) series semiconductor. For example, the light-emitting element (301) may include a compound semiconductor material composed of at least one combination of indium (In), gallium (Ga), aluminum (Al), and nitrogen (N). However, embodiments of the present disclosure are not limited thereto.

[0109] The semiconductor layer (310) of such a light-emitting element (301) may include a first conductivity type semiconductor layer (311), an active layer (312) located on a first surface (the lower surface in the state of FIG. 7) of the first conductivity type semiconductor layer (311), and a second conductivity type semiconductor layer (313) located on the active layer (312).

[0110] Additionally, the light-emitting element (301) may have a first contact layer (330) located on the second surface (upper surface in the structure of FIG. 7) of the first conductivity type semiconductor layer (311). Meanwhile, a second contact layer (320) may be located on the second conductivity type semiconductor layer (313).

[0111] Here, the first contact layer (330) may include a first structural layer (330). The first contact layer (330) may form a multilayer structure. For example, the first structural layer (330) may include a first layer (333) in which gold (Au) and silver (Ag) are mixed, and a second layer (331) located between the first layer (333) and the first conductive semiconductor layer (311) and containing In.

[0112] A passivation layer (350) for protecting the semiconductor layer (310) may be located on the semiconductor layer (310) and the second contact layer (320). When the light-emitting element (301) is subsequently used, for example, when mounted on a display device (10; see FIG. 14), at least a portion of the passivation layer (350) located on the second contact layer (320) may be removed.

[0113] FIG. 7 illustrates a state in which an indium (In) layer is formed on a first conductive semiconductor layer (311). This indium layer can form InN by reacting with nitrogen (N) of the first conductive semiconductor layer (311) after heat treatment. The second layer (331) of the first structural layer (330) may contain InN. For example, the second layer (331) may be formed of InN. A second structural layer (340; see FIG. 9) may be located on this first structural layer (330). For example, the first contact layer (330) may include the first structural layer (330) and the second structural layer (340). In the light-emitting element (301) in the state of FIG. 7, the first contact layer (330) and the first structural layer (330) may be identical. Hereinafter, the first contact layer (330) and the first structural layer (330) are described using the same reference numeral.

[0114] As mentioned above, the first structural layer (330) may include a first layer (333; reflection layer) in which gold (Au) and silver (Ag) are mixed. This first layer (333) can improve the reflection characteristics of the light-emitting element (301). This will be described in detail later.

[0115] As an exemplary embodiment, a second layer (331; ohmic layer) containing In, located between the first layer (333) and the first conductive semiconductor layer (311), may have ohmic contact characteristics. For example, the second layer (331) may contact the first conductive semiconductor layer (311) to allow current to flow smoothly between the first contact layer (330) and the first conductive semiconductor layer (311). For example, the second layer (331) may be formed of indium nitride (InN).

[0116] For example, such a first layer (333) may be in a state where gold (Au) and silver (Ag) are mixed. The first layer (333) may contain silver (Ag) in an amount of 10 to 90 at% and gold (Au) in an amount of 10 to 90 at%. At this time, the first layer (333) may contain 100 at% together with Au, Ag, and unavoidable impurities.

[0117] As an exemplary embodiment, a third layer (332; barrier layer) acting as a barrier between the first layer (333; reflective layer) and the second layer (331; ohmic layer) may be further included.

[0118] For example, this third layer (332) may include at least one of Cr, Ti, Mo, No, and Pt. As an exemplary embodiment, the barrier layer (332) may be formed of chromium (Cr).

[0119] Meanwhile, as an exemplary embodiment, the first layer (333) may further include a fourth layer (334; protective adhesion layer) having protective and adhesive properties. That is, the fourth layer (334) can function as a protective and adhesive layer.

[0120] For example, the fourth layer (334) may include at least one of Cr, Ti, Mo, No, and Pt. As an exemplary embodiment, the protective and adhesive layer (334) may be formed of chromium (Cr).

[0121]

[0122] FIG. 8 is a graph showing the components of the ohmic layer of a light-emitting element before and after heat treatment according to embodiments of the present disclosure.

[0123] Referring to FIG. 8, after the initial In layer is formed (Asdep.), the change in composition in the ohmic layer (331) according to the heat treatment temperature is shown.

[0124] It can be seen that indium metal and indium oxide (In2O3) are detected when the In layer is initially formed. Subsequently, as a heat treatment process is performed at various temperatures (e.g., 300°C, 350°C, and 400°C), the peaks corresponding to indium and indium oxide disappear and indium nitride (InN) is detected.

[0125] Accordingly, it can be seen that the ohmic layer (331) forms InN after the heat treatment process. This InN can form an ohmic contact with the first conductivity type semiconductor layer (311), for example, an n-type GaN layer. This ohmic layer (331) will be described in detail later.

[0126]

[0127] FIG. 9 is a cross-sectional view showing a light-emitting element according to a second embodiment of the present disclosure. FIG. 10 is a photograph mainly showing the first contact layer portion of the light-emitting element according to a second embodiment of the present disclosure.

[0128] Referring to FIG. 9, an example of a light-emitting element (300) having a vertical structure is shown. In FIG. 9, the light-emitting element (300) shows a state in which the light-emitting surface is reversed to the lower side.

[0129] The light-emitting element (300) according to the second embodiment of the present invention may include a semiconductor layer (310) comprising a first conductive semiconductor layer (311), a second conductive semiconductor layer (313), and an active layer (312) located 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) located on a first surface of the first conductive semiconductor layer (311), and a second conductive semiconductor layer (313) located 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.

[0130] 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 focusing on an example where 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.

[0131] As an exemplary embodiment, the light-emitting element (300) may be a blue light-emitting element for emitting blue light. Such a light-emitting element (300) may include a nitride semiconductor. For example, the light-emitting element (300) may include a gallium nitride (GaN) series semiconductor. For example, the light-emitting element (301) may include a compound semiconductor material composed of at least one combination of indium (In), gallium (Ga), aluminum (Al), and nitrogen (N). However, embodiments of the present disclosure are not limited thereto.

[0132] The semiconductor layer (310) of such a light-emitting element (300) may include a first conductivity type semiconductor layer (311), an active layer (312) located on a first surface (the lower surface in the state of FIG. 9) of the first conductivity type semiconductor layer (311), and a second conductivity type semiconductor layer (313) located on the active layer (312).

[0133] Additionally, the light-emitting element (300) may have a first contact layer (330, 340) located on the second surface (upper surface in the structure of FIG. 9) of the first conductivity type semiconductor layer (311). Meanwhile, a second contact layer (320) may be located on the second conductivity type semiconductor layer (313).

[0134] Here, the first contact layer (330, 340) may include a first structural layer (330). The first contact layer (330, 340) may form a multilayer structure. For example, the first structural layer (330) may include a first layer (333) in which gold (Au) and silver (Ag) are mixed, and a second layer (331) which is located between the first layer (333) and the first conductive semiconductor layer (311) and contains In.

[0135] A passivation layer (350) for protecting the semiconductor layer (310) may be located on the semiconductor layer (310) and the second contact layer (320). When the light-emitting element (301) is subsequently used, for example, when mounted on a display device (10; see FIG. 14), at least a portion of the passivation layer (350) located on the second contact layer (320) may be removed.

[0136] The second layer (331) of the first structural layer (330) may include InN. For example, the second layer (331) may be formed of InN. A second structural layer (340) may be located on the first structural layer (330). For example, the first contact layer (330, 340) may include the first structural layer (330) and the second structural layer (340).

[0137] As mentioned above, the first structural layer (330) may include a first layer (333; reflective layer) in which gold (Au) and silver (Ag) are mixed. This first layer (333) can improve the reflective properties of the light-emitting element (300). This will be described in detail later.

[0138] As an exemplary embodiment, a second layer (331; ohmic layer) containing In, located between the first layer (333) and the first conductive semiconductor layer (311), may have ohmic contact characteristics. For example, the second layer (331) may contact the first conductive semiconductor layer (311) to allow current to flow smoothly between the first contact layer (330) and the first conductive semiconductor layer (311). For example, the second layer (331) may form indium nitride (InN).

[0139] For example, such a first layer (333) may be in a state where gold (Au) and silver (Ag) are mixed. The first layer (333) may contain silver (Ag) in an amount of 10 to 90 at% and gold (Au) in an amount of 10 to 90 at%. At this time, the first layer (333) may contain 100 at% together with Au, Ag, and unavoidable impurities.

[0140] As an exemplary embodiment, a third layer (332; barrier layer) acting as a barrier between the first layer (333; reflective layer) and the second layer (331; ohmic layer) may be further included.

[0141] For example, this third layer (332) may include at least one of Cr, Ti, Mo, No, and Pt. As an exemplary embodiment, the barrier layer (332) may be formed of chromium (Cr).

[0142] Meanwhile, as an exemplary embodiment, the first layer (333) may further include a fourth layer (334; protective adhesion layer) having protective and adhesive properties. That is, the fourth layer (334) can function as a protective and adhesive layer.

[0143] For example, the fourth layer (334) may include at least one of Cr, Ti, Mo, No, and Pt. As an exemplary embodiment, the protective and adhesive layer (334) may be formed of chromium (Cr).

[0144] As mentioned above, a second structural layer (340) having magnetic properties may be provided on the first structural layer (330). That is, the first contact layer (330, 340) may include the first structural layer (330) and the second structural layer (340).

[0145] Meanwhile, in order to be used as a subpixel of a display device (10; see FIG. 14), a light-emitting element (300) can be assembled using magnetic force on a wiring board (500; see FIG. 14) or a wiring board (not shown) acting as an assembly board. For example, the light-emitting element (300) can be assembled using magnetic force in a fluid. Accordingly, the light-emitting elements (300) can each be self-assembled at subpixel locations on the wiring board (500).

[0146] Accordingly, the second structural layer (340) having magnetic properties can assist in the process of assembling the light-emitting element (300) to the wiring board (500) according to the magnetic force. A detailed explanation of this is omitted.

[0147] For example, the second structural layer (340) may include a fifth layer (342; magnetic layer) comprising Ni, Co, Fe, Mg, Mn, Sb, Cr, Gd, C, or alloys or oxides thereof. For example, the fifth layer (342) may be formed of Ni (nickel).

[0148] This second structural layer (340) may further include a sixth layer (341; bonding metal layer) located between the first structural layer (330) and the fifth layer (342), and a seventh layer (343; protective metal layer) located on the fifth layer (342). For example, this sixth layer (341) may act as an adhesion metal. Meanwhile, for example, the seventh layer (343) may act as a capping metal.

[0149] For example, at least one of the sixth layer (341) and the seventh layer (343) may include Ti (Titanium). For example, the sixth layer (341) and the seventh layer (343) may be formed of Ti.

[0150] As an exemplary embodiment, the sixth layer (341), fifth layer (342), and seventh layer (343) forming the second structural layer (340) may form a Ti / Ni / Ti structure (see FIG. 10).

[0151] A light-emitting element (300) for self-assembly as described above, for example, a micro LED having a micrometer size, may undergo a fluid dispersion process for self-assembly. However, since the dispersion solution for the fluid dispersion process is an acidic or alkaline solution, it may have an adverse effect on the thin film structure or the metal structure forming the contact layer of the light-emitting element (300).

[0152] In response to this, the contact layer (first contact layer; 330) used in the present disclosure may solve this problem by including a gold (Au)-silver (Ag) mixed reflective layer (333) that is not affected by such dispersion solution.

[0153] As such, according to the present disclosure, the reflective layer (333) can be formed by applying a gold (Au)-silver (Ag) alloy reflective film and improving the chemical resistance of the chemically brittle silver (Ag) metal. In this case, the gold (Au)-silver (Ag) alloy can be formed by heat treatment.

[0154] Meanwhile, regardless of whether heat treatment is performed, due to the high work function of silver (Ag) and gold (Au), the nitride semiconductor (e.g., GaN) thin film and the reflective layer (333) forming the semiconductor layer (310) have high contact resistance, so the driving voltage can be relatively high. For example, the reflective layer (333) can come into contact with the nitrogen face (N-face) of the gallium nitride (GaN) semiconductor.

[0155] In order to lower such high driving voltage and achieve proper ohmic contact, an ohmic layer (331) that lowers contact resistance may be provided between the semiconductor layer (310), for example, the first conductive semiconductor layer (311) and the reflective layer (333). This ohmic layer (331) may contain indium (In) as described above. At this time, a heat treatment process may be performed to lower contact resistance by In and to ensure that gold (Au) and silver (Ag) mix well. During this heat treatment process, In may combine with nitrogen (N) in GaN to form InN. The InN formed at this time may play a major role in lowering contact resistance.

[0156] Meanwhile, during the heat treatment process, when silver (Ag) and gold (Au) are mixed, if silver (Ag) or gold (Au) comes into contact with the nitrogen face (N-face) of the first conductive semiconductor layer (311), for example, gallium nitride (GaN) semiconductor, it may have a negative effect on the contact resistance. Therefore, a barrier layer (332) may be located between the ohmic layer (331) and the reflection layer (333).

[0157] A second structural layer (340) having magnetic properties is provided on the first structural layer (330), and a protective and adhesive layer (334) may be provided to strengthen the adhesive force between the first structural layer (330) and the second structural layer (340).

[0158] Accordingly, the light extraction efficiency of a vertical micro LED can be significantly improved by applying a contact structure that has high reflectivity and is not affected by the dispersion process, which is a process performed in self-assembled light-emitting devices.

[0159]

[0160] FIG. 11 is a graph showing the reflectance of a first structural layer of a light-emitting element according to embodiments of the present disclosure.

[0161] For example, the first structural layer (330) may have an ohmic layer (331), a barrier layer (332), a reflective layer (333), and a protective and adhesive layer (334) positioned in order from the second surface of the first conductive semiconductor layer (311). For example, this first structural layer (330) may form an In(InN) / Cr / Ag-Au / Cr structure (see FIG. 10).

[0162] Referring to FIG. 11, the reflectance of the first structural layer (330) according to the emission wavelength is shown. It can be seen that the reflectance of the first structural layer (330) increases to 80% or more at a wavelength of approximately 450 nm or higher. That is, the first structural layer (330) can have a reflectance of 80% or more at a wavelength of 450 nm or higher.

[0163]

[0164] FIG. 12 is a graph showing the driving voltage of a light-emitting element according to embodiments of the present disclosure.

[0165] Referring to FIG. 12, as an exemplary embodiment, the driving voltage and the corresponding driving current are shown when a first structural layer (330) forming an In(InN) / Cr / Ag-Au / Cr structure and a second structural layer (340) forming a Ti / Ni / Ti structure are used (dotted line).

[0166] FIG. 12 shows a case (solid line) in which a first contact layer forming a Ti / Ni / Ti structure is used as a comparative example, for instance, when a conventional reflective electrode, e.g., silver (Ag) or aluminum (Al), is used. In this case, gold may not be used in the reflective electrode or may be used in relatively less quantity than in the embodiments of the present disclosure.

[0167] The embodiments and comparative examples of the present disclosure each show driving voltages for five examples.

[0168] For example, at a driving current of 5 μA (5.0E-6A), the Ti / Ni / Ti structure (Comparative Example) exhibits a driving voltage of 2.45 to 2.5 V. Meanwhile, the In(InN) / Cr / Ag-Au / Cr structure (Example) exhibits a driving voltage of 2.45 to 2.55 V at a driving current of 5 μA (5.0E-6A).

[0169] As another example, at a driving current of 10 μA (1.0E-5A), the Ti / Ni / Ti structure (comparative example) exhibits a driving voltage of 2.55 to 2.6 V. Meanwhile, the In(InN) / Cr / Ag-Au / Cr structure (example) exhibits a driving voltage of 2.6 to 2.7 V at a driving current of 10 μA (1.0E-5A).

[0170] This is about 0.05 to 0.1V higher than the comparative example in which a conventional reflective electrode is used and a contact layer of a Ti / Ni / Ti structure is used, but it is at a level where it can be judged that there is no significant difference in panel driving. On the other hand, in terms of light extraction, when the reflective film structure according to the embodiments of the present disclosure is applied, the effect of improved light extraction due to the increase in reflectivity is significant. In addition, the contact layer (and / or semiconductor layer) according to the embodiments of the present disclosure has the effect of being protected against a dispersion solution.

[0171]

[0172] FIG. 13 is a cross-sectional view showing a light-emitting element according to a third embodiment of the present disclosure.

[0173] Referring to FIG. 13, another embodiment of a light-emitting element (302) having a vertical structure is shown. In FIG. 13, the light-emitting element (302) shows a state in which the light-emitting surface is reversed to the lower side.

[0174] Hereinafter, the differences from the second embodiment of the present disclosure described above with reference to FIG. 9 will be mainly explained.

[0175] In the light-emitting element (302) according to the third embodiment of the present disclosure, the first contact layer (330, 340) may include a first structural layer (330). The first contact layer (330, 340) may form a multilayer structure. For example, the first structural layer (330) may include a first layer (333) in which gold (Au) and silver (Ag) are mixed, and a second layer (331) located between the first layer (333) and the first conductive semiconductor layer (311) and containing In.

[0176] The second layer (331) of the first structural layer (330) may include InN. For example, the second layer (331) may be formed of InN. A second structural layer (340) may be located on the first structural layer (330). For example, the first contact layer (330, 340) may include the first structural layer (330) and the second structural layer (340).

[0177] In this embodiment, as an example, a third layer (332; barrier layer) acting as a barrier between the first layer (333; reflective layer) and the second layer (331; ohmic layer) may be omitted.

[0178] Meanwhile, as an exemplary embodiment, the first layer (333) may further include a fourth layer (334; protective adhesion layer) having protective and adhesive properties. That is, the fourth layer (334) can function as a protective and adhesive layer.

[0179] For example, the fourth layer (334) may include at least one of Cr, Ti, Mo, No, and Pt. As an exemplary embodiment, the protective and adhesive layer (334) may be formed of chromium (Cr).

[0180] As mentioned above, a second structural layer (340) having magnetic properties may be provided on the first structural layer (330). That is, the first contact layer (330, 340) may include the first structural layer (330) and the second structural layer (340).

[0181] Parts not described herein may be identical to the second embodiment of the present disclosure. Therefore, redundant descriptions are omitted.

[0182]

[0183] FIG. 14 is a cross-sectional view showing a display device having a light-emitting element according to embodiments of the present disclosure.

[0184] Referring to FIG. 14, a blue light-emitting element (300B), a red light-emitting element (300R), and a green light-emitting element (300G) according to embodiments of the present disclosure can be used as unit subpixels and assembled on a wiring board (500) to form a display device (10).

[0185] As mentioned above, the blue light-emitting element (300B), the red light-emitting element (300R), and the green light-emitting element (300G) according to the embodiments of the present disclosure can be assembled to a wiring board (500) through a self-assembly process using magnetic force. A detailed description of this self-assembly process is omitted.

[0186] In this way, light-emitting elements (300R, 300G, 300B) are transferred to a wiring board (500) so that a display device (10) as shown in FIG. 15 can be manufactured.

[0187] Referring to FIG. 14, the display device (10) according to the present embodiment may be configured such that light-emitting elements (300R, 300G, 300B) forming unit subpixels are arranged on a wiring substrate (500) on which a first electrode (510) is arranged.

[0188] 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 a partitioned manner on the wiring board (500). Here, the wiring electrodes may be used as data electrodes (pixel electrodes) or scan electrodes (common electrodes).

[0189] In FIG. 14, three light-emitting elements (300R, 300G, 300B) may form a unit pixel. At this time, it may include 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. These unit pixels may be repeatedly provided on a wiring substrate (500).

[0190] Although not illustrated, the first electrode (510) arranged on the wiring substrate (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.

[0191] 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.

[0192] In order to provide upper and lower 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 (330, 340) of the light-emitting elements (300R, 300G, 300B) may be larger than the area of ​​the surface far from the first contact layer (330, 340).

[0193] Meanwhile, an organic barrier (521) may be located between the light-emitting element (300R, 300G, 300B) and the first electrode (510). The first contact layer (330, 340) of the light-emitting element (300R, 300G, 300B) may be insulated by the organic barrier (521).

[0194] Additionally, the display device (10) may include a first connecting electrode (530) that electrically connects one side of the first electrode (510) and the light-emitting element (300R, 300G, 300B). This first connecting electrode (530) may be made of a metal with high electrical conductivity such as Al, Mo, Cu, Ag, Pt, etc.

[0195] 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 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 the surface formed by the light-emitting layer (312) of the light-emitting element (300R, 300G, 300B). This first connecting electrode (530) may be extended laterally to the side of the first conductive semiconductor layer (311) of the light-emitting element (300R, 300G, 300B) and may be electrically connected to the first conductive semiconductor layer (311).

[0196] Referring to FIG. 14, the first connecting electrode (530) may be provided on both sides of the light-emitting elements (300R, 300G, 300B). In some cases, the first connecting electrode (530) may be provided to cover along the side of the light-emitting elements (300R, 300G, 300B).

[0197] A flattening layer (520) may be positioned on the side of the first connecting electrode (530) and the light-emitting element (300R, 300G, 300B). The flattening layer (520) may cover the first connecting electrode (530) and the light-emitting element (300R, 300G, 300B). The flattening 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.

[0198] A second connecting electrode (540) may be located on the flattening layer (520) and electrically connected to the other side of the light-emitting element (300R, 300G, 300B). For example, this second connecting electrode (540) may include a transparent electrode such as ITO. Thus, light emitted from the light-emitting element (300R, 300G, 300B) can pass through the second connecting electrode (540) and be emitted to the outside.

[0199] Referring to FIG. 14, the second connecting electrode (540) may be partially located on the light-emitting elements (300R, 300G, 300B). In some cases, these second connecting electrodes (540) may be connected to each other by additional second electrodes (not shown).

[0200]

[0201] The above description is merely an illustrative explanation of the technical concept of the present disclosure, and those skilled in the art to which the present disclosure pertains may make various modifications and variations within the scope of the essential characteristics of the present disclosure without departing from its nature.

[0202] Accordingly, the embodiments disclosed in this disclosure are intended to explain, not limit, the technical concept of this disclosure, and the scope of the technical concept of this disclosure is not limited by these embodiments.

[0203] The scope of protection of the present disclosure shall be interpreted by the claims below, and all technical ideas within the equivalent scope shall be interpreted as being included within the scope of rights of the present disclosure.

[0204] 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 conductivity type semiconductor layer; An active layer located on a first surface of the first conductivity type semiconductor layer; A second conductivity type semiconductor layer located on the above active layer; A first contact layer located on a second surface of the first conductivity type semiconductor layer; and It includes a second contact layer located on the second conductivity type semiconductor layer, and The first contact layer above is It includes a first structural layer having reflective properties, and The above first structural layer is, A first layer mixed with gold (Au) and silver (Ag); and A second layer comprising In, located between the first layer and the first conductivity type semiconductor layer. Light-emitting element.

2. In Paragraph 1, The first layer above contains silver in a ratio of 10 to 90 at% and gold in a ratio of 10 to 90 at%. Light-emitting element.

3. In Paragraph 1, The second layer above forms the InN Light-emitting element.

4. In Paragraph 1, The structure further includes a third layer acting as a barrier layer between the first layer and the second layer. Light-emitting element.

5. In Paragraph 1, The above-mentioned first layer further comprises a fourth layer acting as a protective and adhesive layer. Light-emitting element.

6. In Paragraph 1, The first structural layer has a reflectance of 80% or more at a wavelength of 450 nm or more. Light-emitting element.

7. In Paragraph 1, A second structural layer located on the first structural layer and having magnetic properties further comprising Light-emitting element.

8. In Paragraph 7, The second structural layer comprises a fifth layer comprising Ni, Co, Fe, Mg, Mn, Sb, Cr, Gd, C, or alloys or oxides thereof. Light-emitting element.

9. In Paragraph 8, The above second structural layer A sixth layer located between the first structural layer and the fifth layer; and A seventh layer further comprising a seventh layer located on the fifth layer. Light-emitting element.

10. First conductivity type semiconductor layer; An active layer located on a first surface of the first conductivity type semiconductor layer; A second conductivity type semiconductor layer located on the above active layer; A first contact layer located on a second surface of the first conductivity type semiconductor layer; and It includes a second contact layer located on the second conductivity type semiconductor layer, and The first contact layer above is It includes a first structural layer having reflective properties, and The above first structural layer is, An ohmic layer comprising InN in contact with the first conductive semiconductor layer; and A reflective layer comprising a mixture of gold (Au) and silver (Ag) located on the above ohmic layer Light-emitting element.

11. In Paragraph 10, In the above reflective layer, the gold protects the silver from chemical reactions. Light-emitting element.

12. In Paragraph 10, The above reflective layer contains silver in a ratio of 10 to 90 at% and gold in a ratio of 10 to 90 at%. Light-emitting element.

13. In Paragraph 10, The ohmic layer and the reflective layer further include a third layer acting as a barrier layer. Light-emitting element.

14. In Paragraph 10, A magnetic layer further comprising a magnetic layer located on the above-mentioned reflective layer and having magnetic properties Light-emitting element.

15. In a display device using a light-emitting element, A wiring board on which a first electrode is arranged; A light-emitting element comprising a semiconductor layer disposed on the above-mentioned wiring substrate and forming a unit subpixel; A first connecting electrode that electrically connects the first electrode and one side of the semiconductor layer of the light-emitting element; A planarization layer covering the light-emitting element and the first connecting electrode; and It is configured to include a second connecting electrode located on the planarization layer and electrically connected to the other side of the semiconductor layer of the light-emitting element, and The above light-emitting element is, A first contact layer located on a first surface of the semiconductor layer; and It includes a second contact layer located on a second surface of the semiconductor layer, and The first contact layer above is It includes a first structural layer having reflective properties, and The above first structural layer is, A first layer mixed with gold (Au) and silver (Ag); and A second layer comprising In, located between the first layer and the second conductivity semiconductor layer. Display device.

Images