Light emitting element, method for manufacturing light emitting element, and display device including light emitting element

Abstract

A light emitting element includes a first semiconductor layer including a first type semiconductor; a second semiconductor layer including a second type semiconductor different from the first type semiconductor; an active layer provided between one surface of the first semiconductor layer and one surface of the second semiconductor layer; a first electrode layer arranged on the other surface of the second semiconductor layer and having a first sectional area; and a second electrode layer arranged on the other surface of the first semiconductor layer and having a second sectional area smaller than the first sectional area. A side surface of the light emitting element defined by the first semiconductor layer, the active layer, the second semiconductor layer, and the second electrode layer is perpendicular to a main surface of the first electrode layer.

Description

Technical Field

[0001] The embodiments of this disclosure relate to a light-emitting element, a method of manufacturing the light-emitting element, and a display device including the light-emitting element. Background Technology

[0002] Recently, with the increasing interest in information display, research and development of display devices are ongoing. Summary of the Invention

[0003] Technical issues

[0004] The embodiments of this disclosure provide a light-emitting element, a method for manufacturing the light-emitting element, and a display device including the light-emitting element, wherein misarrangement of the light-emitting element is avoided (or substantially avoided) and luminous efficiency is improved.

[0005] It should be noted that the aspects and features of this disclosure are not limited to those described above, and other aspects and features of this disclosure will be clearly understood by those skilled in the art through the following description.

[0006] Technical solution

[0007] According to embodiments of this disclosure, a light-emitting element includes: a first semiconductor layer comprising a first type of semiconductor; a second semiconductor layer comprising a second type of semiconductor different from the first type of semiconductor; an active layer between one surface of the first semiconductor layer and one surface of the second semiconductor layer; a first electrode layer on the other surface of the second semiconductor layer and having a first cross-sectional area; and a second electrode layer on the other surface of the first semiconductor layer and having a second cross-sectional area smaller than the first cross-sectional area. The side surface of the light-emitting element defined by the first semiconductor layer, the active layer, the second semiconductor layer, and the second electrode layer is perpendicular to the main surface of the first electrode layer.

[0008] The first electrode layer and the second electrode layer may each include a transparent conductive material.

[0009] Transparent conductive materials may include any transparent conductive oxide (TCO) selected from indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), gallium-doped zinc oxide (GZO), zinc tin oxide (ZTO), gallium tin oxide (GTO), and fluorine-doped tin oxide (FTO).

[0010] The first electrode layer may include a transparent conductive material, and the second electrode layer may include a reflective material.

[0011] Reflective materials may include any one selected from chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), nickel (Ni), and their oxides or alloys.

[0012] Each of the first semiconductor layer, the active layer, and the second semiconductor layer may have a second cross-sectional area.

[0013] The angle between the busbar of the light-emitting element and the first electrode layer can be 90°.

[0014] The light-emitting element may also include an insulating film covering at least a portion of the active layer.

[0015] The cross-section of each of the second electrode layer, the first semiconductor layer, the active layer, and the second semiconductor layer can have one of a circular shape, an elliptical shape, and a polygonal shape.

[0016] According to another embodiment of this disclosure, a method for manufacturing a light-emitting element includes the following steps: sequentially disposing of an undoped semiconductor layer, a first semiconductor layer, an active layer, a second semiconductor layer, a first electrode layer, and a bonding layer on a stacked substrate; separating the stacked substrate from the undoped semiconductor layer; separating the undoped semiconductor layer from the first semiconductor layer; positioning a second electrode layer on the first semiconductor layer; performing a first etching process in a direction from the first semiconductor layer toward the second semiconductor layer to remove at least a portion of each of the second electrode layer, the first semiconductor layer, the active layer, the second semiconductor layer, and the first electrode layer; performing a second etching process in a direction from the first semiconductor layer toward the second semiconductor layer to etch a side surface of each of the second electrode layer, the first semiconductor layer, the active layer, and the second semiconductor layer; and separating the bonding layer from the first electrode layer. The step of performing the second etching process includes etching a side surface of the light-emitting element defined by the first semiconductor layer, the active layer, the second semiconductor layer, and the second electrode layer perpendicular to the main surface of the first electrode layer, and the step of performing the first etching process includes etching the first electrode layer to have a first cross-sectional area and etching the second electrode layer to have a second cross-sectional area smaller than the first cross-sectional area.

[0017] The steps of performing the first etching process may include etching each of the first semiconductor layer, the active layer, and the second semiconductor layer to have a cross-sectional area different from the second cross-sectional area.

[0018] The steps of performing the second etching process may include etching each of the first semiconductor layer, the active layer, and the second semiconductor layer to have a second cross-sectional area.

[0019] The second etching process can be performed after the first etching process.

[0020] Laser lift-off methods can be used to separate stacked substrates from undoped semiconductor layers.

[0021] The undoped semiconductor layer can be separated from the first semiconductor layer through an etch-back process.

[0022] The method may also include forming an insulating film to extend around the outer peripheral surface of the active layer.

[0023] The method may also include forming an etch mask pattern for use in a first etch process.

[0024] According to another embodiment of this disclosure, a display device includes: a substrate; a light-emitting element, the light-emitting element including a first semiconductor layer comprising a first type of semiconductor, a second semiconductor layer comprising a second type of semiconductor different from the first type of semiconductor, an active layer between one surface of the first semiconductor layer and one surface of the second semiconductor layer, a first electrode layer on another surface of the second semiconductor layer and having a first cross-sectional area, and a second electrode layer on another surface of the first semiconductor layer and having a second cross-sectional area; a first contact electrode on the substrate and electrically connected to the second electrode layer of the light-emitting element; and a second contact electrode on the substrate and electrically connected to the first electrode layer of the light-emitting element. The first contact electrode is between the substrate and the second contact electrode, and the second electrode layer is between the substrate and the first electrode layer.

[0025] The first contact electrode may include a reflective material, and each of the first electrode layer, the second electrode layer, and the second contact electrode may include a transparent conductive material.

[0026] The first electrode layer may include a reflective material, and each of the second contact electrode and the second electrode layer may include a transparent conductive material.

[0027] The aspects and features of this disclosure are not limited to those discussed above, and those skilled in the art will understand other aspects and features of this disclosure through the disclosure provided below and the accompanying drawings.

[0028] Beneficial effects

[0029] According to embodiments of the present disclosure, a light-emitting element, a method of manufacturing the light-emitting element, and a display device including the light-emitting element are provided, which prevent or substantially prevent misalignment of the light-emitting element and improve luminous efficiency.

[0030] The aspects and features of this disclosure are not limited to those described above, and other aspects and features of this disclosure will be readily understood by those skilled in the art from the disclosure provided herein and the accompanying drawings. Attached Figure Description

[0031] Figure 1 and Figure 2These are perspective and cross-sectional views showing the light-emitting element according to an embodiment.

[0032] Figure 3 and Figure 4 These are perspective and cross-sectional views showing a light-emitting element according to another embodiment.

[0033] Figures 5 to 15 This is a cross-sectional view of the process of manufacturing a light-emitting element according to an embodiment.

[0034] Figure 16 This is a plan view illustrating a display device including a light-emitting element according to an embodiment.

[0035] Figure 17 It is along Figure 16 A sectional view taken by line I-I'. Detailed Implementation

[0036] The embodiments described herein are provided to clearly explain the scope of this disclosure to those skilled in the art, and are not intended to limit the disclosure. It should be understood that this disclosure may include substitutions and modifications to the described embodiments within the technical scope of this disclosure.

[0037] The terminology used in this specification is selected from commonly used terms based on the functionality of components according to embodiments of this disclosure, and may have meanings that vary depending on the intent of those skilled in the art, custom in the art, or the emergence of new technologies. Where a particular term is used with a specific meaning, that meaning is specifically described. Therefore, the terms used in this specification should not be defined as simple names of components, but rather as having their actual meaning within the context of this specification.

[0038] The accompanying drawings are provided to facilitate the interpretation of this disclosure, and for the purpose of interpretation, the shapes in the drawings may be exaggerated; therefore, this disclosure should not be limited to the drawings.

[0039] In addition, details of well-known functions and structures can be omitted.

[0040] It will be understood that when an element or layer is referred to as being "on," "connected to," or "bonded to" another element or layer, the element or layer may be directly on, directly connected to, or directly bonded to the other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is referred to as being "directly on," "directly connected to," or "directly bonded to" another element or layer, no intermediary element or layer is present. For example, when a first element is described as being "bonded" or "connected" to a second element, the first element may be directly bonded to or directly connected to the second element, or the first element may be indirectly bonded to or indirectly connected to the second element via one or more intermediary elements.

[0041] The same reference numerals denote the same elements. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Furthermore, when describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” Expressions such as “at least one of…” before (or after) a list of elements modify the entire list of elements but not individual elements within that list. As used herein, the term “use” and variations thereof may be considered synonymous with the term “utilize” and variations thereof, respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms rather than terms of degree and are intended to explain the inherent variation in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0042] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or portion discussed below may be referred to as the second element, component, region, layer, or portion.

[0043] For ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature as shown in the accompanying drawings and another (other) element or feature. It will be understood that, in addition to the orientations depicted in the accompanying drawings, the spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the accompanying drawings is flipped, an element described as “below” or “under” another element or feature will subsequently be oriented “above” or “above” said other element or feature. Thus, the term “below” can cover both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein should be interpreted accordingly.

[0044] As used herein, unless the context clearly indicates otherwise, the singular forms “a” and “an (kind / owner)” are intended to also include the plural forms. It will also be understood that the terms “comprising,” “including,” and / or variations thereof, when used in this specification, indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof.

[0045] In the following text, reference will be made to Figures 1 to 17 The present invention describes a light-emitting element, a method for manufacturing a light-emitting element, and a display device including a light-emitting element according to embodiments.

[0046] Figure 1 and Figure 2 These are perspective and cross-sectional views showing the light-emitting element according to an embodiment. Figure 3 and Figure 4 These are perspective and cross-sectional views showing a light-emitting element according to another embodiment.

[0047] Reference Figures 1 to 4 The light-emitting element (LD) may include a first semiconductor layer 11, an active layer 12, a second semiconductor layer 13, an insulating film 14, a first electrode layer 16, and a second electrode layer 17. The first electrode layer 16, the second semiconductor layer 13, the active layer 12, the first semiconductor layer 11, and the second electrode layer 17 may be stacked sequentially in the direction of the height H of the light-emitting element (LD), for example, the height direction.

[0048] One of the first semiconductor layer 11 and the second semiconductor layer 13 may be disposed at a position adjacent to the first end EP1 of the light-emitting element LD (or disposed at the position located at the first end EP1 of the light-emitting element LD), and the other of the first semiconductor layer 11 and the second semiconductor layer 13 may be disposed at a position adjacent to the second end EP2 of the light-emitting element LD (or disposed at the position located at the second end EP2 of the light-emitting element LD).

[0049] In the following text, for ease of description, the region corresponding to one end of the light-emitting element LD in which the first semiconductor layer 11 is disposed is defined as the first end EP1, and the region corresponding to the other end of the light-emitting element LD in which the second semiconductor layer 13 is disposed is defined as the second end EP2. In the following text, for ease of description, the surface corresponding to the first end EP1 is defined as the first surface S1 of the light-emitting element LD, and the surface corresponding to the second end EP2 is defined as the second surface S2 of the light-emitting element LD.

[0050] Light-emitting elements (LDs) can have dimensions ranging from nanometers to micrometers. However, the size of LDs is not limited to this and can vary depending on the design conditions of various devices (e.g., display devices) that use light-emitting devices that include LDs as light sources.

[0051] The first semiconductor layer 11 may be configured to be closer to the first surface S1 than to the second surface S2. The first semiconductor layer 11 may be a first conductivity type semiconductor layer (or a first type semiconductor layer). For example, the first semiconductor layer 11 may include an N-type semiconductor layer. As an example, the first semiconductor layer 11 may include an N-type semiconductor layer comprising any semiconductor material selected from InAlGaN, GaN, AlGaN, InGaN, AlN, and InN and doped with a first conductivity type dopant such as silicon (Si), germanium (Ge), or tin (Sn). However, the materials included in (or constituting) the first semiconductor layer 11 are not limited to these, and the first semiconductor layer 11 may include various suitable materials (or may be made of various suitable materials).

[0052] The active layer 12 can be disposed on the first semiconductor layer 11 and can be formed as a single quantum well structure or a multi-quantum well structure. The position of the active layer 12 can vary depending on the type of light-emitting element (LD). As an example, the first semiconductor layer 11 of the light-emitting element LD can be implemented as multiple layers, and the active layer 12 can be disposed between multiple first semiconductor layers 11.

[0053] A coating layer doped with a conductive dopant may be formed on and / or beneath the active layer 12. As an example, the coating layer may be (or may be formed as) an AlGaN layer or an InAlGaN layer. According to embodiments, materials such as AlGaN or InAlGaN may be included in (or may be used to form) the active layer 12; furthermore, various suitable materials may be included in (or may constitute) the active layer 12.

[0054] The second semiconductor layer 13 is disposed on the active layer 12 and may include a semiconductor layer having a different conductivity type (or type) than the first semiconductor layer 11. The second semiconductor layer 13 may be configured to be closer to the second surface S2 than to the first surface S1. For example, the second semiconductor layer 13 may include a P-type semiconductor layer. As an example, the second semiconductor layer 13 may include a P-type semiconductor layer comprising any semiconductor material selected from InAlGaN, GaN, AlGaN, InGaN, AlN, and InN and doped with a second conductivity type dopant such as magnesium (Mg). However, the materials included in (or constituting) the second semiconductor layer 13 are not limited thereto, and the second semiconductor layer 13 may include various suitable materials (or may be made of various suitable materials).

[0055] In the following description, for convenience, an embodiment in which the first semiconductor layer 11 includes an N-type semiconductor layer and the second semiconductor layer 13 includes a P-type semiconductor layer will be given.

[0056] When a voltage greater than or equal to the threshold voltage is applied to the two ends (e.g., opposite ends) of the light-emitting element LD, electrons and holes recombine with each other in the active layer 12, thus providing (or emitting) light from (or through) the active layer 12. Therefore, the light-emitting element LD emits light. By controlling the emission of light from the light-emitting element LD using this principle, the light-emitting element LD can be used as a light source for various light-emitting devices, including pixels in display devices.

[0057] An insulating film 14 may be formed on the surface of the light-emitting element LD to at least surround the outer surface of the active layer 12 (e.g., extending around the periphery of the active layer 12). Furthermore, the insulating film 14 may surround at least a portion of each of the first semiconductor layer 11, the second semiconductor layer 13, the first electrode layer 16, and the second electrode layer 17.

[0058] The insulating film 14 may include a transparent insulating material. According to an example, the insulating film 14 may be formed as a single layer or may have a multilayer structure, and may include materials selected from silicon oxide (SiO2). x ), silicon nitride (SiN) x ), silicon oxynitride (SiO) x Ny ), aluminum oxide (AlO) x ) and titanium dioxide (TiO) x At least one insulating material (e.g., aluminum oxide (AlO)) x ) and silicon dioxide (SiO) x (The double layer is made of ) However, this disclosure is not limited thereto, and the insulating film 14 may be omitted according to the embodiments.

[0059] The first electrode layer 16 may be formed on the second semiconductor layer 13. For example, the first electrode layer 16 may be disposed on one surface of the second semiconductor layer 13, and the active layer 12 may be disposed on the other surface of the second semiconductor layer 13.

[0060] The first electrode layer 16 may include a transparent conductive material. According to an example, the first electrode layer 16 may include a transparent conductive material, such as at least one transparent conductive oxide selected from indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), gallium-doped zinc oxide (GZO), zinc tin oxide (ZTO), gallium tin oxide (GTO), and fluorine-doped tin oxide (FTO), but this disclosure is not limited to the above examples.

[0061] The second electrode layer 17 can be formed on the first semiconductor layer 11. For example, the second electrode layer 17 can be disposed on one surface of the first semiconductor layer 11, and the active layer 12 can be disposed on the other surface (e.g., the opposite surface) of the first semiconductor layer 11.

[0062] The second electrode layer 17 may include a semi-transparent conductive material. The second electrode layer 17 may include a reflective material. The reflective material may have a reflectivity of 90% or greater. According to examples, the second electrode layer 17 may include at least one selected from chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), nickel (Ni), and their oxides or alloys, but this disclosure is not limited to the examples described above.

[0063] However, according to an embodiment, the second electrode layer 17 may include a transparent conductive material. As an example, similar to the first electrode layer 16, the second electrode layer 17 may include a transparent conductive material, such as at least one transparent conductive oxide selected from indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO), gallium-doped zinc oxide (GZO), zinc tin oxide (ZTO), gallium tin oxide (GTO), and fluorine-doped tin oxide (FTO), but this disclosure is not limited to the above examples.

[0064] The second electrode layer 17 and the first electrode layer 16 can be ohmic electrodes, but this disclosure is not limited thereto. The second electrode layer 17 and the first electrode layer 16 can be Schottky electrodes.

[0065] The first end EP1 and the second end EP2 of the light-emitting element LD can have different polarities. At least one of the first end EP1 and the second end EP2 of the light-emitting element LD can be exposed, and the first end EP1 and / or the second end EP2 of the light-emitting element LD can be electrically connected to an external component.

[0066] Each of the first surface S1 and the second surface S2 of the light-emitting element LD can have any shape among circular, elliptical, and polygonal shapes. According to one embodiment, each of the first surface S1 and the second surface S2 of the light-emitting element LD can have a circular or elliptical shape. According to another embodiment, the first surface S1 of the light-emitting element LD can have an n-sided shape (where n is an integer of three or greater than three), and the second surface S2 of the light-emitting element LD can have an n-sided shape similar to the upper surface (e.g., the first surface S1). In some embodiments, the shapes of the first surface S1 and the second surface S2 of the light-emitting element LD can be any of rectangles, squares, equilateral triangles, regular pentagons, and regular octagons, but are not limited to these examples.

[0067] Reference Figure 1 and Figure 2 According to the embodiment, the first surface S1 and the second surface S2 of the light-emitting element LD can be circular in shape with different areas. (Refer to...) Figure 3 and Figure 4 According to another embodiment, the first surface S1 and the second surface S2 of the light-emitting element LD can be rectangular in shape with different areas.

[0068] The area of ​​the first surface S1 of the light-emitting element LD can be smaller than the area of ​​the second surface S2 of the light-emitting element LD. The area of ​​the second electrode layer 17 can be smaller than the area of ​​the first electrode layer 16. As an example, the first surface S1 can have a first area, and the second surface S2 can have a second area larger than the first area. For example, based on the direction of height H, the area of ​​the upper surface of the light-emitting element LD can be different from the area of ​​the lower surface of the light-emitting element LD.

[0069] According to an embodiment, the height H of the light-emitting element LD can be smaller than the diameter D of the second surface S2 (see embodiment). Figure 1 and Figure 2 According to another embodiment, the height H of the light-emitting element LD can be less than the length L of one side of the second surface S2 (see...). Figure 3 and Figure 4 ).

[0070] According to an embodiment, when manufacturing a display device, misalignment of the light-emitting elements (LDs) can be prevented or mitigated. For example, when the cross-sectional area of ​​the second surface S2 is greater than the cross-sectional area of ​​the first surface S1, the probability that the first surface S1 of the light-emitting element LD faces downwards is greater than the probability that the second surface S2 of the light-emitting element LD faces downwards. Therefore, the light-emitting elements LD can be arranged primarily with the first surface S1 facing downwards.

[0071] The cross-sectional areas of the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13 can be substantially the same. A line (or surface) defined by the side surface of the light-emitting element LD and the second surface S2 of the light-emitting element LD can form an angle of the first angle θ1. The side surface of the light-emitting element LD can be defined by the first semiconductor layer 11, the active layer 12, the second semiconductor layer 13, and the second electrode layer 17.

[0072] According to an embodiment, the side surface of the light-emitting element LD can be perpendicular to the main surface MS of the first electrode layer 16. The first angle θ1 can be the angle between the generative line GL of the light-emitting element LD and the second surface S2. In this embodiment, the first angle θ1 can be in the range of about 85° to about 90°. The first angle θ1 can be substantially 90°. The generative line GL of the light-emitting element LD can form an angle of about 90° with the first electrode layer 16.

[0073] Light-emitting devices including the aforementioned light-emitting element (LD) can be used in various types of devices (including display devices) that require a light source. For example, the light-emitting element (LD) can be disposed in each pixel of a display panel, and the light-emitting element (LD) can serve as the light source for each pixel. However, the application areas of the light-emitting element (LD) are not limited to the examples described above. For example, the light-emitting element (LD) can be used in other types of devices (such as lighting devices) that use (or include) a light source (e.g., excluding another light source).

[0074] In the following text, reference will be made to Figures 5 to 15 A method for manufacturing a light-emitting element according to an embodiment is described in detail.

[0075] Figures 5 to 15 This is a cross-sectional view of the process of manufacturing a light-emitting element according to an embodiment.

[0076] Reference Figure 5 A stacked substrate 1 can be set, and an undoped semiconductor layer 10 can be formed on the stacked substrate 1.

[0077] The stacked substrate 1 can be a substrate plate used for stacking target materials. The stacked substrate 1 can be a wafer used for epitaxial growth of a material. By way of example, the stacked substrate 1 can be any of, but is not limited to, a sapphire substrate, a GaAs substrate, a Ga substrate, and an InP substrate. For example, when a particular material satisfies the selectivity for manufacturing a light-emitting element (LD) and the material can be epitaxially grown smoothly, that particular material can be selected as the material for the stacked substrate 1. The surface of the stacked substrate 1 can be flat. The shape of the stacked substrate 1 can be a rectangular polygon or a circular shape, but is not limited to these.

[0078] The undoped semiconductor layer 10 may be a semiconductor layer to which no dopant is disposed. According to an embodiment, the undoped semiconductor layer 10 may include any semiconductor material selected from InAlGaN, GaN, AlGaN, InGaN, AlN, and InN, but individual dopants may not be disposed on the undoped semiconductor layer 10. The etch rate of the undoped semiconductor layer 10 to which no dopant is disposed may differ from the etch rate of the first semiconductor layer 11.

[0079] The undoped semiconductor layer 10 can be formed by any of the following methods: metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), vapor phase epitaxy (VPE), liquid phase epitaxy (LPE).

[0080] A sacrificial layer may be disposed between the stacked substrate 1 and the undoped semiconductor layer 10. During the fabrication process of the light-emitting element LD, the sacrificial layer can separate the stacked substrate 1 and the undoped semiconductor layer 10 from each other. The sacrificial layer may include any one selected from GaAs, AlAs, and AlGaAs, but this disclosure is not limited thereto.

[0081] Reference Figure 6 A first semiconductor layer 11 is formed on the undoped semiconductor layer 10. An active layer 12 may be formed on the first semiconductor layer 11, and a second semiconductor layer 13 may be formed on the active layer 12. The first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13 may be provided by epitaxial growth, and may be provided by any of the above-described example methods as methods for forming the undoped semiconductor layer 10.

[0082] As described above, the first semiconductor layer 11 and the second semiconductor layer 13 can be configured as different types of semiconductor layers. Therefore, the active layer 12 can be located between the first semiconductor layer 11 and the second semiconductor layer 13 with different polarities, and light can be emitted from the active layer 12 when electrical information with a threshold voltage or higher voltage is provided to both ends of the light-emitting element LD.

[0083] Reference Figure 7A first electrode layer 16 can be formed on the second semiconductor layer 13. According to an example, the first electrode layer 16 can be deposited on the second semiconductor layer 13 by a deposition process. The first electrode layer 16 may include components selected from those referenced above. Figures 1 to 4 At least one of the materials listed exemplarily.

[0084] Reference Figure 8 A bonding layer 19 can be disposed on the first electrode layer 16. The bonding layer 19 may include a bonding substrate and a connection electrode layer. In this embodiment, the bonding substrate may be a silicon wafer substrate, but is not limited thereto. The connection electrode layer can be provided by being applied to the bonding substrate. The bonding layer 19 can be configured such that the connection electrode layer faces the first electrode layer 16. Thereafter, the connection electrode layer and the first electrode layer 16 can bond to each other under temperature and pressure conditions (e.g., predetermined temperature and pressure conditions), thus the bonding layer 19 can be located on the first electrode layer 16. According to an embodiment, an insulating film can be disposed on the first electrode layer 16, and the insulating film can be connected to the connection electrode layer of the bonding layer 19.

[0085] Reference Figure 9 The stacked substrate 1 and the undoped semiconductor layer 10 can be separated. The stacked substrate 1 and the undoped semiconductor layer 10 can be separated by a laser lift-off (LLO) method. However, this disclosure is not limited thereto, and according to other embodiments, the undoped semiconductor layer 10 and the first semiconductor layer 11 can be separated by a chemical lift-off (CLO) method.

[0086] Subsequently, refer to Figure 10 The undoped semiconductor layer 10 can be separated from the first semiconductor layer 11. The etch rate of the undoped semiconductor layer 10 can be different from the etch rate of the first semiconductor layer 11. As an example, the undoped semiconductor layer 10 can have a first etch rate, and the first semiconductor layer 11 can have a second etch rate different from the first etch rate. The etch-back process can be performed using (or based on) the difference between the first etch rate and the second etch rate. The etch-back process can be performed in the region between the undoped semiconductor layer 10 and the first semiconductor layer 11, therefore, the undoped semiconductor layer 10 and the first semiconductor layer 11 can be separated without performing a separate optical process.

[0087] Reference Figure 11 A second electrode layer 17 can be disposed on the first semiconductor layer 11. Similar to the first electrode layer 16, the second electrode layer 17 can be stacked on the first semiconductor layer 11 using a deposition process. The second electrode layer 17 may include components selected from those referenced above. Figures 1 to 4 At least one of the example materials described.

[0088] As described above, the second electrode layer 17, the first semiconductor layer 11, the active layer 12, the second semiconductor layer 13 and the first electrode layer 16 stacked sequentially can form a light-emitting stack structure 5.

[0089] Reference Figure 12 A first etching process can be performed on the light-emitting stacked structure 5. The light-emitting stacked structure 5 can be etched in the stacking direction to form a light-emitting stacked pattern 20. The light-emitting stacked pattern 20 can correspond to the area that was not removed by etching in the stacking direction. The stacking direction can be a direction perpendicular to the main surface of the bonding layer 19.

[0090] To form the light-emitting stacked pattern 20, a mask can be set across the entire surface of the light-emitting stacked structure 5, and an etching process can be performed to pattern it at nanometer- or micrometer-level intervals (or "spacing"). An etch mask pattern, wherein at least one of a circular shape, an elliptical shape, and an n-sided shape (where n is an integer of three or greater) is periodically arranged when viewed in a planar view, can be used to perform the etching process on the light-emitting stacked structure 5. The light-emitting stacked pattern 20 can be set when the light-emitting stacked structure 5 is etched in the stacking direction using the formed etch mask pattern.

[0091] Subsequently, the second electrode layer 17, the first semiconductor layer 11, the active layer 12, the second semiconductor layer 13, and the first electrode layer 16 can have different cross-sectional areas. The cross-sectional area of ​​the surface of the light-emitting stack pattern 20 parallel to the main surface of the bonding layer 19 can decrease with increasing distance from the bonding layer 19. For example, the area of ​​the first electrode layer 16 in contact with the bonding layer 19 can be different from the area of ​​the second electrode layer 17 exposed to the outside. The cross-sectional area of ​​the first semiconductor layer 11 can be different from the cross-sectional area of ​​the second semiconductor layer 13.

[0092] Subsequently, refer to Figure 13 A second etching process can be performed on the second electrode layer 17, the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13. The second etching process may not be performed on the first electrode layer 16. The second etching process can be a wet etching using a KOH solution, but is not limited to this. The second etching process can be performed after the first etching process.

[0093] In one embodiment, a second etching process may be performed such that the side surfaces of the second electrode layer 17, the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13 are parallel to the stacking direction. The side surfaces of the second electrode layer 17, the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13 are perpendicular to the main surface of the bonding layer 19.

[0094] After performing the second etching process, the surfaces of the second electrode layer 17, the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13 that are perpendicular to the stacking direction may have the same (or substantially the same) cross-sectional area.

[0095] In the light-emitting stacked pattern 20, the surfaces of the second electrode layer 17, the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13 that are parallel to the main surface of the bonding layer 19 can have the same cross-sectional area.

[0096] Refer to the above for execution. Figure 12 Following the first etching process described, some cross-sectional areas of the light-emitting stacked pattern 20 may differ. Because surface defects and / or damage exist on the etched surface, the luminous efficiency of the light-emitting element (LD) may be reduced. However, the above-described etching process can be performed... Figure 13 The second etching process described can at least partially remove the side surfaces of the second electrode layer 17, the first semiconductor layer 11, the active layer 12, and the second semiconductor layer 13. Therefore, surface defects present on the etched surface can be reduced or removed, and damaged etched surfaces can be reduced, resulting in improved luminous efficiency of the resulting light-emitting element (LD).

[0097] Subsequently, referring to Figure 14 An insulating film 14 can be formed. The insulating film 14 can be formed by applying an insulating material to the light-emitting stacked pattern 20. According to embodiments, the insulating film 14 can be formed using atomic layer deposition (ALD), sol-gel processes, or chemical vapor deposition methods (e.g., plasma-enhanced chemical vapor deposition (PECVD) methods), but this disclosure is not limited thereto.

[0098] In one embodiment, the insulating film 14 may cover the first semiconductor layer 11, the active layer 12, the second semiconductor layer 13, and the first electrode layer 16. After the insulating film 14 is disposed on one surface of the second electrode layer 17, the insulating film 14 can be removed by a separate process. Thus, at least a portion of the second electrode layer 17 can be exposed to the outside. However, according to embodiments, the process of forming the insulating film 14 may be omitted, or the insulating film 14 may be provided as multiple layers.

[0099] Reference Figure 15 This allows the bonding layer 19 to be removed. The luminescent stacked pattern 20 can then be separated from the bonding layer 19 to set the reference above. Figures 1 to 4 The light-emitting element LD is described. According to an embodiment, after removing the bonding layer 19, a process for removing impurities present on the outer surface of the light-emitting element LD can be further performed, but this disclosure is not limited thereto.

[0100] Subsequently, the light-emitting element (LD) can be dispersed in a solvent, making it possible to prepare an ink comprising the LD and the solvent.

[0101] In the following text, reference will be made to Figure 16 and Figure 17 A display device including a light-emitting element (LD) according to an embodiment is described.

[0102] Figure 16 This is a plan view illustrating a display device including a light-emitting element according to an embodiment.

[0103] As an example of an electronic device that can use a light-emitting element (LD) as a light source, in Figure 16 The image shows a display device (specifically, a display panel PNL included in the display device). For convenience, in... Figure 16 The diagram schematically illustrates the structure of the display panel PNL based on the display area DA. However, in embodiments, at least one drive circuit unit (e.g., at least one of a scan driver and a data driver), lines, and / or pads (or "solder pads" or "solder pads") may be further disposed on the display panel PNL.

[0104] Reference Figure 16 The display panel PNL may include a base SUB and pixels PXL disposed on the base SUB. Multiple pixels PXL may be disposed on the base SUB.

[0105] The substrate SUB can be (or can constitute) the matrix component of the display panel PNL, and can be a rigid substrate (or film) or a flexible substrate (or film).

[0106] The display panel PNL and the substrate SUB used to form the display panel PNL may include a display area DA for displaying images and a non-display area NDA other than the display area DA.

[0107] Pixel PXL can be located in the display area DA. Pixel PXL may include a light-emitting element LD. Various lines, pads, and / or embedded circuit units of pixel PXL connected to the display area DA can be located in the non-display area NDA. Pixel PXL can be arranged in a stripe pattern or... (A registered trademark of Samsung Display Co., Ltd.) The arrangement structure (e.g., a diamond arrangement structure) is regularly arranged. However, the arrangement structure of the pixels PXL is not limited to this, and the pixels PXL can be arranged in the display area DA in various structures and / or ways.

[0108] According to an embodiment, two or more types of pixels PXL emitting light of different colors can be disposed in the display area DA. As an example, pixel PXL may include a first pixel PXL1 emitting a first color of light, a second pixel PXL2 emitting a second color of light, and a third pixel PXL3 emitting a third color of light. At least one first pixel PXL1, at least one second pixel PXL2, and at least one third pixel PXL3 disposed adjacent to each other can form (or may constitute) a pixel unit configured to emit light of various colors. For example, first pixel PXL1, second pixel PXL2, and third pixel PXL3 may each be a sub-pixel emitting light of a predetermined color. According to an embodiment, first pixel PXL1 may be a red pixel emitting red light, second pixel PXL2 may be a green pixel emitting green light, and third pixel PXL3 may be a blue pixel emitting blue light, but this disclosure is not limited thereto.

[0109] In one embodiment, the first pixel PXL1, the second pixel PXL2, and the third pixel PXL3 may each include a first-color light-emitting element, a second-color light-emitting element, and a third-color light-emitting element as light sources to emit first-color light, second-color light, and third-color light, respectively. In another embodiment, the first pixel PXL1, the second pixel PXL2, and the third pixel PXL3 may include light-emitting elements that emit light of the same color. Furthermore, the first pixel PXL1, the second pixel PXL2, and the third pixel PXL3 may include color conversion layers and / or color filters of different colors disposed on the light-emitting elements to emit first-color light, second-color light, and third-color light. However, the color, type, and / or number of pixels PXL constituting each pixel unit are not specifically limited. For example, the color of the light emitted by each pixel PXL can be changed differently.

[0110] Pixel PXL may include at least one light source driven by control signals (e.g., scan signals and data signals) and / or power sources (e.g., a first power source and a second power source). In one embodiment, each pixel PXL may be formed as an active pixel. However, the type, structure, and / or driving method of pixel PXL applicable to a display device is not specifically limited. For example, each pixel PXL having various suitable structures and / or driving methods may be formed as a pixel of a passive or active light-emitting display device.

[0111] Figure 17 It is along Figure 16 A sectional view taken by line I-I'. Figure 17 The structure of pixel PXL is schematically shown in the diagram. Figure 17 For ease of description, the transistor connected to the light-emitting element LD and the wires connected to the transistor are omitted.

[0112] Reference Figure 17 The pixel PXL may include a substrate SUB and a display element DPL.

[0113] The substrate SUB can be a rigid substrate or a flexible substrate. Depending on the example, the substrate SUB may include rigid or flexible materials. However, the material of the substrate SUB is not limited to the specific example.

[0114] The display element section (DPL) can be located on the substrate (SUB). The display element section (DPL) may include a pixel electrode (PE), a light-emitting element (LD), a connecting electrode (CE), a protective layer (PVX), a barrier layer (BNK), and an encapsulation layer (ENC). The pixel electrode (PE) may be referred to as the first contact electrode relative to the light-emitting element (LD), and the connecting electrode (CE) may be referred to as the second contact electrode relative to the light-emitting element (LD).

[0115] The pixel electrode PE can be disposed on the substrate SUB. The pixel electrode PE can be an anode. The pixel electrode PE can include at least a conductive material. According to an example, the pixel electrode PE can include a reflective conductive material, so that light emitted by the light-emitting element LD toward the pixel electrode PE can travel in the display direction of the light-emitting element LD (e.g., third-direction DR3).

[0116] According to the example, the pixel electrode PE may include copper (Cu), gold (Au), silver (Ag), magnesium (Mg), aluminum (Al), platinum (Pt), lead (Pb), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr), lithium (Li), calcium (Ca) or mixtures thereof, and may include indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) or indium oxide (In2O3), but this disclosure is not limited thereto.

[0117] At least a portion of the connecting electrode CE may be disposed on the substrate SUB, and at least another portion of the connecting electrode CE may be configured to be electrically connected to one end of the light-emitting element LD. The connecting electrode CE may be disposed in the display area DA in the form of a plate, but this disclosure is not limited thereto.

[0118] The connecting electrode CE may include a transparent conductive material (or transparent conductive substance), such as a transparent conductive oxide selected from indium tin oxide (ITO), indium zinc oxide (IZO), zinc aluminum oxide (AZO), gallium-doped zinc oxide (GZO), zinc tin oxide (ZTO), gallium tin oxide (GTO), and fluorine-doped tin oxide (FTO). In other embodiments, the connecting electrode CE may include a semi-transparent conductive material (or semi-transparent conductive substance), such as magnesium (Mg), silver (Ag), or an alloy of magnesium (Mg) and silver (Ag).

[0119] An electrical signal can flow between the pixel electrode PE and the connecting electrode CE, and the light-emitting element LD can emit light when the electrical signal flows. For example, the electrical signal can flow in the light-emitting element LD in a direction from the first end EP1 toward the second end EP2 or from the second end EP2 toward the first end EP1.

[0120] The polarity of the pixel electrode PE can be different from that of the connecting electrode CE. For example, when the pixel electrode PE is a cathode, the connecting electrode CE can be an anode, and when the pixel electrode PE is an anode, the connecting electrode CE can be a cathode. The following description will be based on the pixel electrode PE being an anode and the connecting electrode CE being a cathode.

[0121] The pixel electrode PE and the connection electrode CE can be configured to be separate and spaced apart from each other. The pixel electrode PE can provide the electrical signal from the transistor to the light-emitting element LD.

[0122] When an electrical signal is provided, the light-emitting element (LD) can emit light. The LD can output light in the display direction (e.g., third direction DR3). The LD can be arranged on the pixel electrode PE.

[0123] The light-emitting element (LD) can be arranged such that its first end EP1 faces the pixel electrode PE. The LD can also be arranged such that its second end EP2 faces the connection electrode CE. The first end EP1 of the LD can be electrically connected to the pixel electrode PE, and the second end EP2 can be electrically connected to the connection electrode CE. For example, the second semiconductor layer 13 of the LD can be electrically connected to the connection electrode CE, and the first semiconductor layer 11 of the LD can be electrically connected to the pixel electrode PE.

[0124] At least a portion of the first surface S1 of the light-emitting element LD can be in physical contact with the pixel electrode PE. At least a portion of the second surface S2 of the light-emitting element LD can be in physical contact with the connection electrode CE.

[0125] The first surface S1 of the light-emitting element LD can be connected to the pixel electrode PE to form a contact area, and the second surface S2 of the light-emitting element LD can be connected to the connecting electrode CE to form a contact area that is at least larger than the contact area between the first surface S1 and the pixel electrode PE. For example, the contact area between the first electrode layer 16 of the light-emitting element LD and the connecting electrode CE can be larger than the contact area between the second electrode layer 17 of the light-emitting element LD and the pixel electrode PE.

[0126] According to one embodiment, the first electrode layer 16 of the light-emitting element LD may include a transparent conductive material, and the second electrode layer 17 of the light-emitting element LD may include a reflective material disposed on the pixel electrode PE. In this embodiment, light emitted from the light-emitting element LD can be reflected by the second electrode layer 17 along the display direction (e.g., third direction DR3), thereby improving the luminous efficiency of the light-emitting element LD.

[0127] According to another embodiment, the first electrode layer 16 and the second electrode layer 17 of the light-emitting element LD may include a transparent conductive material, and the pixel electrode PE may include a reflective material. In this embodiment, the pixel electrode PE reflects light emitted from the light-emitting element LD along the display direction, thereby improving the luminous efficiency of the light-emitting element LD.

[0128] The protective layer PVX can be configured to surround the light-emitting element LD (e.g., extend around the periphery of the light-emitting element LD). The protective layer PVX can eliminate step differences caused by the light-emitting element LD, etc. The protective layer PVX may include organic insulating materials such as polyacrylate resins, epoxy resins, phenolic resins, polyamide resins, polyimide resins, unsaturated polyester resins, polystyrene resins, polyphenylene sulfide resins, or benzocyclobutene (BCB), but this disclosure is not limited thereto.

[0129] The dam BNK may have a shape that protrudes (bulges) in the display direction (e.g., third direction DR3). Pixel electrodes PE may be arranged between adjacent dam BNKs. The dam BNK may comprise organic or inorganic materials, but this disclosure is not limited to specific examples.

[0130] The encapsulation layer ENC may be located on the connection electrode CE. At least a portion of the encapsulation layer ENC may be located on the embankment BNK. The encapsulation layer ENC may be located on the outer portion of the display element portion DPL to planarize the separated components. The encapsulation layer ENC may include organic or inorganic materials, but this disclosure is not limited to specific materials.

[0131] Those skilled in the art will understand that various modifications, alterations, and substitutions can be made without departing from the spirit and scope of this disclosure. Therefore, the above embodiments of this disclosure can be implemented independently or in combination with each other.

[0132] Therefore, the embodiments disclosed herein do not limit the technical scope of this disclosure but rather interpret it, and the technical scope of this disclosure will not be limited by the described embodiments. The scope of protection of this disclosure should be interpreted based on the appended claims, and all technical ideas included within the scope of equivalents of the claims should be interpreted as being included within the scope of this disclosure.

Claims

1. A light-emitting element for use in a display device, the light-emitting element comprising: The first semiconductor layer includes an N-type semiconductor; The second semiconductor layer includes a P-type semiconductor; An active layer is located between one surface of the first semiconductor layer and one surface of the second semiconductor layer, and directly contacts the one surface of the first semiconductor layer and the one surface of the second semiconductor layer; The first electrode layer is directly disposed on the other surface of the second semiconductor layer and has a first cross-sectional area; The second electrode layer is on the other surface of the first semiconductor layer and has a second cross-sectional area smaller than the first cross-sectional area. as well as An insulating film covering at least a portion of the active layer. Wherein, the side surface of the light-emitting element defined by the first semiconductor layer, the active layer, the second semiconductor layer, and the second electrode layer is perpendicular to the main surface of the first electrode layer. The insulating film continuously covers the second electrode layer, the first semiconductor layer, the active layer, the respective side surfaces of the second semiconductor layer, a portion of the main surface, and the side surface of the first electrode layer. Wherein, the side surface of the first electrode layer is inclined relative to the main surface of the first electrode layer.

2. The light-emitting element according to claim 1, wherein The first electrode layer and the second electrode layer each comprise a transparent conductive material.

3. The light-emitting element according to claim 2, wherein The transparent conductive material includes any one of the transparent conductive oxides selected from indium tin oxide, indium zinc oxide, aluminum zinc oxide, gallium-doped zinc oxide, zinc tin oxide, gallium tin oxide, and fluorine-doped tin oxide.

4. The light-emitting element according to claim 1, wherein The first electrode layer comprises a transparent conductive material, and The second electrode layer includes a reflective material.

5. The light-emitting element according to claim 4, wherein The reflective material includes any one selected from chromium, titanium, aluminum, gold, nickel, and their oxides or alloys.

6. The light-emitting element according to claim 1, wherein Each of the first semiconductor layer, the active layer, and the second semiconductor layer has the second cross-sectional area.

7. The light-emitting element according to claim 1, wherein, The angle between the busbar of the light-emitting element and the first electrode layer is 90°.

8. The light-emitting element according to claim 1, wherein, The cross-section of each of the second electrode layer, the first semiconductor layer, the active layer, and the second semiconductor layer has one of a circular shape, an elliptical shape, and a polygonal shape.

9. A method for manufacturing a light-emitting element, the method comprising the following steps: An undoped semiconductor layer, a first semiconductor layer, an active layer, a second semiconductor layer, a first electrode layer, and a bonding layer are sequentially disposed on a stacked substrate. Separate the stacked substrate from the undoped semiconductor layer; Separate the undoped semiconductor layer from the first semiconductor layer; Position the second electrode layer on the first semiconductor layer; In the direction from the first semiconductor layer toward the second semiconductor layer, a first etching process is performed to remove at least a portion of each of the second electrode layer, the first semiconductor layer, the active layer, the second semiconductor layer, and the first electrode layer; In the direction from the first semiconductor layer toward the second semiconductor layer, a second etching process is performed to etch the side surface of each of the second electrode layer, the first semiconductor layer, the active layer, and the second semiconductor layer, such that the side surface of the light-emitting element defined by the first semiconductor layer, the active layer, the second semiconductor layer, and the second electrode layer is perpendicular to the main surface of the first electrode layer; as well as Separate the bonding layer from the first electrode layer. The step of performing the first etching process includes etching the first electrode layer to have a first cross-sectional area and etching the second electrode layer to have a second cross-sectional area smaller than the first cross-sectional area.

10. The method according to claim 9, wherein, The step of performing the first etching process includes etching each of the first semiconductor layer, the active layer, and the second semiconductor layer to have a cross-sectional area different from the second cross-sectional area.

11. The method according to claim 10, wherein, The step of performing the second etching process includes etching each of the first semiconductor layer, the active layer, and the second semiconductor layer to have the second cross-sectional area.

12. The method according to claim 11, wherein, The second etching process is performed after the first etching process.

13. The method according to claim 9, wherein, Laser lift-off is used to separate the stacked substrate from the undoped semiconductor layer.

14. The method according to claim 9, wherein, The undoped semiconductor layer is separated from the first semiconductor layer by an etch-back process.

15. The method of claim 9, further comprising forming an insulating film extending around the outer peripheral surface of the active layer.

16. The method of claim 9, further comprising forming an etch mask pattern for use in the first etch process.

17. A display device, the display device comprising: Base; A light-emitting element, comprising: a first semiconductor layer including an N-type semiconductor; a second semiconductor layer including a P-type semiconductor; an active layer between one surface of the first semiconductor layer and one surface of the second semiconductor layer; a first electrode layer on the other surface of the second semiconductor layer and having a first cross-sectional area; a second electrode layer on the other surface of the first semiconductor layer and having a second cross-sectional area; and an insulating film covering at least a portion of the active layer; A first contact electrode is disposed on the substrate and electrically connected to the second electrode layer of the light-emitting element; and The second contact electrode is located on the substrate and is electrically connected to the first electrode layer of the light-emitting element. Wherein, the side surface of the light-emitting element defined by the first semiconductor layer, the active layer, the second semiconductor layer, and the second electrode layer is perpendicular to the main surface of the first electrode layer. The insulating film continuously covers the second electrode layer, the first semiconductor layer, the active layer, the respective side surfaces of the second semiconductor layer, a portion of the main surface of the first electrode layer, and the side surfaces of the first electrode layer. Wherein, the side surface of the first electrode layer is inclined relative to the main surface of the first electrode layer. The first contact electrode is located between the substrate and the second contact electrode. The second electrode layer is located between the substrate and the first electrode layer, and The area of ​​the first cross-section is greater than the area of ​​the second cross-section.

18. The display device according to claim 17, wherein, The first contact electrode includes a reflective material, and Each of the first electrode layer, the second electrode layer, and the second contact electrode comprises a transparent conductive material.

19. The display device according to claim 17, wherein, The second electrode layer includes a reflective material, and Each of the second contact electrode and the first electrode layer comprises a transparent conductive material.

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