Light emitting diode device, method for manufacturing the same, and display device including the same

Abstract

A light emitting diode (LED) device, a method for manufacturing the LED device, and a display device including the LED device are provided. The LED device includes a light emitting layer having a core-shell structure, a passivation layer provided to cover a portion of the top surface of a first semiconductor layer, a first electrode provided on the light emitting layer, and a second electrode provided below the light emitting layer. The light emitting layer includes a first semiconductor layer, an active layer, and a second semiconductor layer. The first electrode is provided to contact the first semiconductor layer, and the second electrode is provided to contact the second semiconductor layer.

Description

Technical Field

[0001] The present disclosure relates to a light emitting diode (LED) device, a method of manufacturing the LED device, and a display apparatus including the LED device. Background Art

[0002] As display devices, liquid crystal displays (LCDs) and organic light emitting diode (OLED) displays are widely used. Recently, a technology for manufacturing a high-resolution display device using a micro-sized LED device has attracted attention. Summary of the invention

[0003] The present disclosure provides an LED device, a method of manufacturing the LED device, and a display apparatus including the LED device.

[0004] Additional aspects will be set forth in part in the following description and in part will be apparent from the description or may be learned by practice of the presented example embodiments of the present disclosure. According to one aspect of the present disclosure, a light emitting diode (LED) device is provided, comprising: a light emitting layer, comprising a first semiconductor layer, an active layer, and a second semiconductor layer, the light emitting layer having a core-shell structure; a passivation layer, provided to cover a portion of the top surface of the first semiconductor layer; a first electrode, provided on a first side of the light emitting layer to contact the first semiconductor layer; and a second electrode, provided on a second side of the light emitting layer to contact the second semiconductor layer.

[0005] The first semiconductor layer may be provided in a three-dimensional (3D) shape, wherein the active layer is provided to cover a bottom surface and side surfaces of the first semiconductor layer, and wherein the second semiconductor layer is provided on the active layer.

[0006] The passivation layer may be provided to cover the entire side surface of the light emitting layer, a first portion of a top surface of the first semiconductor layer, and a first portion of a bottom surface of the second semiconductor layer.

[0007] The first electrode may be provided to contact a second portion of a top surface of the first semiconductor layer at a first opening in the passivation layer, and the second electrode may be provided to contact a second portion of a bottom surface of the second semiconductor layer at a second opening in the passivation layer.

[0008] The first electrode may include a transparent electrode, and the second electrode may include a reflective electrode.

[0009] The second portion of the top surface of the first semiconductor layer may include a concavo-convex structure for improving light extraction.

[0010] The first semiconductor layer, the active layer, and the second semiconductor layer may include nitride semiconductor materials.

[0011] According to one aspect of the present disclosure, a display device is provided, comprising: a plurality of pixels arranged two-dimensionally to emit light of different colors, wherein the plurality of pixels include a plurality of light emitting diode (LED) devices, each of the plurality of LED devices including: a light emitting layer including a first semiconductor layer, an active layer, and a second semiconductor layer, the light emitting layer having a core-shell structure; a passivation layer provided to cover a portion of a top surface of the first semiconductor layer; a first electrode provided on a first side of the light emitting layer to contact the first semiconductor layer; and a second electrode provided on a second side of the light emitting layer to contact the second semiconductor layer.

[0012] The first semiconductor layer may be provided in a three-dimensional (3D) shape, wherein the active layer may be provided to cover a bottom surface and side surfaces of the first semiconductor layer, and wherein the second semiconductor layer is provided on the active layer.

[0013] The passivation layer may be provided to cover the entire side of the light emitting layer, a first portion of a top surface of the first semiconductor layer, and a first portion of a bottom surface of the second semiconductor layer.

[0014] A second portion of the top surface of the first semiconductor layer at the opening in the passivation layer may include a concavo-convex structure for improving light extraction.

[0015] The plurality of pixels may include a plurality of LED devices emitting light of different wavelength bands.

[0016] The plurality of pixels may include a plurality of LED devices emitting light of the same wavelength band.

[0017] The plurality of pixels may include a plurality of blue LED devices.

[0018] One or more first pixels among the plurality of pixels may further include a green conversion layer that converts blue light into green light, and one or more second pixels among the plurality of pixels may further include a red conversion layer that converts blue light into red light.

[0019] According to one aspect of the present disclosure, a method for manufacturing a light emitting diode (LED) device is provided, the method comprising: forming a film on a substrate; forming a light emitting layer by sequentially depositing a first semiconductor layer in a three-dimensional (3D) shape, an active layer covering a top surface and a side surface of the first semiconductor layer, and a second semiconductor layer covering the active layer on the film; and forming a first electrode and a second electrode respectively contacting the first semiconductor layer and the second semiconductor layer.

[0020] The forming of the film may include: forming a sacrificial pattern on the substrate; forming a film material layer on the substrate to cover the sacrificial pattern; removing the sacrificial pattern; and crystallizing the film material layer.

[0021] The method may further include: forming a passivation layer to cover the light emitting layer; and forming a first opening in the passivation layer at a portion of a top surface of the light emitting layer by etching the passivation layer.

[0022] The method may further include forming a second opening in the passivation layer at a portion of the bottom surface of the first semiconductor layer by removing the film.

[0023] The method may further include: before forming the first electrode, forming a concavo-convex structure on a second portion of the bottom surface of the first semiconductor layer.

[0024] According to one aspect of the present disclosure, a light emitting diode (LED) device is provided, comprising: a light emitting layer having a core-shell structure; a passivation layer provided to cover the light emitting layer, including an end portion at a first surface of a first semiconductor layer covering an active layer, the passivation layer including a first opening at a first portion on the first surface of the first semiconductor layer and a second opening at a second portion on the first surface of the second semiconductor layer; a first electrode provided in the first opening to contact the first semiconductor layer; and a second electrode provided in the second opening to contact the second semiconductor layer. The light emitting layer may include: a first semiconductor layer having a first surface through which light is emitted; an active layer formed adjacent to the first semiconductor layer, the active layer surrounding a second surface, a third surface, and a fourth surface of the first semiconductor layer, the second surface being opposite to the first surface, the third surface and the fourth surface being side surfaces of the first semiconductor layer; and a second semiconductor layer formed adjacent to the active layer.

[0025] The LED device may further include a plurality of protrusions formed on the first surface of the first semiconductor layer at the first opening.

[0026] The plurality of protrusions may be separated by one or more membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other aspects, features and advantages of certain example embodiments of the present disclosure will be more apparent from the following description in conjunction with the accompanying drawings, in which:

[0028] Figure 1 is a cross-sectional view of a light emitting diode (LED) device according to an example embodiment;

[0029] Figure 2 is a cross-sectional view of an LED device according to another example embodiment;

[0030] Figure 3 is a cross-sectional view of an LED device according to another example embodiment;

[0031] Figure 4 is a plan view schematically showing a display device according to an example embodiment;

[0032] Figures 5 to 16 is a diagram for describing a method of manufacturing an LED device according to an example embodiment;

[0033] Fig.17 is a diagram for describing a method of manufacturing an LED device according to another example embodiment;

[0034] Figures 18 to 28 is a diagram for describing a method of manufacturing an LED device according to another example embodiment;

[0035] Fig.29 is a diagram for describing a method of manufacturing an LED device according to another example embodiment;

[0036] Fig.30 is a diagram for describing a method of manufacturing an LED device according to another example embodiment; and

[0037] Fig.31 is a diagram for describing a method of manufacturing an LED device according to another example embodiment. DETAILED DESCRIPTION

[0038] Hereinafter, the example embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals refer to the same elements, and the size of each element may be exaggerated for the sake of clarity and convenience of description. Meanwhile, the following example embodiments of the present disclosure are merely illustrative, and various modifications may be made from the example embodiments of the present disclosure.

[0039] Hereinafter, the expression “on…” or “on…” may include not only “directly on… in a contacting manner” but also “on… in a non-contacting manner”. The singular form is also intended to include the plural form unless the context clearly indicates otherwise. When a part “includes” a component, unless other specific words are given, the description does not mean to exclude other components but means to include other components as well.

[0040] The term "the" and similar indicative terms similar thereto may correspond to both singular and plural forms. Unless there is an explicit disclosure or other disclosure of the order of operations of the method, the operations may be performed in an appropriate order. The order of operations is not limited to the order of operations mentioned.

[0041] Terms such as “unit” or “module” used in the embodiments mean a unit for processing at least one function or operation and can be implemented in hardware, software, or a combination of hardware and software.

[0042] The connecting lines or connectors shown in the various figures presented are intended to represent exemplary functional relationships and / or physical or logical couplings between the various elements.

[0043] The use of all examples or exemplary terms is only intended to describe the technical spirit in detail, and the scope is not limited by the examples or exemplary terms unless defined by the claims.

[0044] Figure 1 is a cross-sectional view of a light emitting diode (LED) device according to an example embodiment.

[0045] Reference Figure 1 , the LED device 100 has a vertical type electrode structure. More specifically, the LED device 100 may include a light emitting layer 110, a first electrode 130, and a second electrode 140. According to an example embodiment, the first electrode 130 is provided above the light emitting layer 110, and the second electrode 140 is provided below the light emitting layer 110. Here, the light emitting layer 110 may include an LED layer based on an inorganic material.

[0046] The light emitting layer 110 may have a core-shell structure. The core-shell structure may mean a structure in which a shell provided on the outside surrounds a core provided on the inside. According to an example embodiment, the light emitting layer 110 may have a core-shell structure in which a portion of the core is not covered by the shell but is opened (e.g., exposed). According to an example embodiment, the top surface of the core may not be covered by the shell and may be open. The light emitting layer 110 may include a first semiconductor layer 111, an active layer 113, and a second semiconductor layer 112. The first semiconductor layer 111 corresponds to the core of the core-shell structure, and may have a three-dimensional (3D) shape having a relatively thick thickness compared to the active layer 113 and the second semiconductor layer 112.

[0047] The first semiconductor layer 111 may include, for example, an n-type semiconductor. However, the present disclosure is not limited thereto, and the first semiconductor layer 111 may include a p-type semiconductor as the case may be. For example, the first semiconductor layer 111 may include an n-type semiconductor of the III-V group, such as an n-type nitride semiconductor. Here, the nitride semiconductor may include, but is not limited to, for example, GaN, InN, AlN, or a combination thereof. For example, the first semiconductor layer 111 may include n-GaN. The first semiconductor layer 111 may have a single-layer or multi-layer structure.

[0048] The active layer 113 and the second semiconductor layer 112 correspond to the shell of the core-shell structure and may have a relatively thin thickness compared to the first semiconductor layer 111. The active layer 113 may be provided to cover the bottom surface and the side of the first semiconductor layer 111 having a 3D shape, and the second semiconductor layer 112 may be provided to cover the active layer 113. Therefore, the top surface of the first semiconductor layer 111 may not be covered by the active layer 113 and the second semiconductor layer 112, but may be opened.

[0049] The active layer 113 may generate light of a specific wavelength band by recombination of electrons and holes. The active layer 113 may have a multiple quantum well (MQW) structure. However, the present disclosure is not limited thereto, and the active layer 113 may have a single quantum well (SQW) structure as the case may be. The active layer 113 may include a semiconductor of the III-V group, such as a nitride semiconductor. For example, the active layer 113 may include GaN.

[0050] The second semiconductor layer 112 may be provided to cover the active layer 113. The second semiconductor layer 112 may include, for example, a p-type semiconductor. However, the present disclosure is not limited thereto, and the second semiconductor layer 112 may include an n-type semiconductor as the case may be. The second semiconductor layer 112 may include a p-type semiconductor of the III-V group, such as a p-type nitride semiconductor. For example, the second semiconductor layer 112 may include p-GaN. The second semiconductor layer 112 may have a single layer or a multilayer structure.

[0051] The light emitting layer 110 having a core-shell structure may be formed by growing on a crystallized film spaced apart from a substrate with a cavity therebetween by metal organic chemical vapor deposition (MOCVD) as described below.

[0052] The film may serve as a seed layer for growth of the light emitting layer 110. The film may relieve stress that may cause dislocation together with the light emitting layer 110 grown on the film, so that the light emitting layer 110 grown on the film may have high quality with low defect density.

[0053] According to an example embodiment, a passivation layer 120 may be provided on the light emitting layer 110. Here, the passivation layer 120 may be provided to cover the surface of the light emitting layer except for a portion 111a of the top surface of the first semiconductor layer 111 and a portion 112a of the bottom surface of the second semiconductor layer 112. Therefore, the passivation layer 120 may be provided to cover the end of the active layer 113 exposed on the top surface of the light emitting layer 110. Therefore, light leaking from the end of the active layer 113 may be blocked, improving light extraction efficiency. The passivation layer 120 may include, for example, silicon oxide or silicon nitride, but this is only an example.

[0054] According to an example embodiment, the first electrode 130 may be provided to be electrically connected to the first semiconductor layer 111. More specifically, the first electrode 130 may be provided on the passivation layer 120 to contact an open surface of the first semiconductor layer 111. For example, a portion 111a of the top surface of the first semiconductor layer 111 is opened by not being covered by the passivation layer 120.

[0055] The first electrode 130 may include a transparent electrode. When the first semiconductor layer 111 includes, for example, an n-type nitride semiconductor, the first electrode 130 may include an n-type electrode. The first electrode 130 may include a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), etc. However, the present disclosure is not limited to this example.

[0056] The second electrode 140 may be provided to be electrically connected to the second semiconductor layer 112. More specifically, the second electrode 140 may be provided on the passivation layer 120 to contact an open surface of the second semiconductor layer 112. For example, a portion 112a of the bottom surface of the second semiconductor layer 112 is opened by not being covered by the passivation layer 120.

[0057] The second electrode 140 may include a reflective electrode. When the second semiconductor layer 112 includes, for example, a p-type nitride semiconductor, the second electrode 140 may include a p-type electrode. The second electrode 140 may include a metal material having excellent conductivity.

[0058] According to an exemplary embodiment, when a voltage is applied to each of the first electrode 130 and the second electrode 140 in the LED device 100 configured as described above, electrons and holes are recombined in the active layer 113 of the light emitting layer 110, thereby generating light of a certain wavelength band and emitting the light outside the LED device 100. Here, the light emitting layer 110 may adjust the band gap according to the type of material constituting the light emitting layer 110, thereby emitting light of a desired wavelength band. For example, the LED device 100 may emit red light, green light, or blue light by being applied as a pixel of a display device.

[0059] The LED device 100 may include a micro-sized LED device. More specifically, the LED device 100 may have a size of, for example, about 100 μm×100 μm or less and a thickness of about 10 μm or less. However, the present disclosure is not limited to this example.

[0060] According to an exemplary embodiment of the present disclosure, the light emitting layer 110 may be grown on a crystallized film that is spaced apart from the substrate and has a cavity therebetween, thereby reducing stress that may be generated in the light emitting layer 110 and thus forming a high-quality light emitting layer 110 with a low defect density. Therefore, an LED device 100 having high efficiency and high reliability and improved light extraction efficiency may be implemented. In addition, a passivation layer 120 may be provided to cover an end portion of the active layer 113 on the top surface of the light emitting layer 110, thereby improving current injection characteristics and thus improving light extraction efficiency.

[0061] Figure 2 is a cross-sectional view of an LED device according to another exemplary embodiment. Hereinafter, the description will be focused on the differences from the aforementioned exemplary embodiment.

[0062] Reference Figure 2 , the LED device 200 may include a light emitting layer 210 having a core-shell structure, a first electrode 130 provided on the light emitting layer 210, and a second electrode 140 provided under the light emitting layer 210. The light emitting layer 210 may include a first semiconductor layer 211 having a 3D shape, an active layer 213 provided to cover the bottom surface and side surfaces of the first semiconductor layer 211, and a second semiconductor layer 212 provided to cover the active layer.

[0063] According to an example embodiment, the passivation layer 120 may be provided on the light emitting layer 210. Here, the passivation layer 120 may be provided to cover the surface of the light emitting layer 210 except for a portion of the top surface of the first semiconductor layer 211 and a portion 212a of the bottom surface of the second semiconductor layer 212.

[0064] The portion of the top surface of the first semiconductor layer 211 opened by the passivation layer 120 may include a concavo-convex structure as a light extraction surface. Here, the concavo-convex structure may include a plurality of protrusions 211a' to improve light extraction. Each protrusion 211a' may have, for example, a polygonal trumpet shape or a conical shape. However, this is only an example, and each protrusion 211a' may have other various shapes.

[0065] According to this example embodiment, by forming the concavo-convex structure on the portion of the top surface of the first semiconductor layer 211 as a light extraction surface, light extraction efficiency may be further improved.

[0066] Figure 3 is a cross-sectional view of an LED device according to another exemplary embodiment. Hereinafter, the description will be focused on the differences from the aforementioned exemplary embodiment.

[0067] Reference Figure 3, the LED device 300 may include a light emitting layer 310 having a core-shell structure, a first electrode 130 provided on the light emitting layer 310, and a second electrode 140 provided under the light emitting layer 310. The light emitting layer 310 may include a first semiconductor layer 311 having a 3D shape, an active layer 313 provided to cover the bottom surface and side surfaces of the first semiconductor layer 311, and a second semiconductor layer 312 provided to cover the active layer 313.

[0068] According to an example embodiment, the passivation layer 120 may be provided on the light emitting layer 310. Here, the passivation layer 120 may be provided to cover the surface of the light emitting layer except for a portion of the top surface of the first semiconductor layer 311 and a portion of the bottom surface of the second semiconductor layer 312. On the portion of the top surface of the first semiconductor layer 311 opened by the passivation layer 120, a plurality of films 150 are provided to be spaced apart from each other, and portions of the top surface of the first semiconductor layer 311 are opened between the films 150. Here, the films 150 are provided by Fig.25 The process shown is provided, which will be described later.

[0069] The portion of the top surface of the first semiconductor layer 311 opened between the films 150 may include a concavo-convex structure as a light extraction surface. Here, the concavo-convex structure may include a plurality of protrusions 311a' to improve light extraction. However, the present disclosure is not limited to this example, and therefore, according to another example embodiment, the plurality of protrusions 311a' may not be provided.

[0070] Figure 4 is a plan view schematically illustrating a display device according to an example embodiment. Figure 4 The display device 1000 shown may be, for example, a micro LED display device. However, the present disclosure is not limited to this example.

[0071] Reference Figure 4 , the display device 1000 may include a plurality of unit pixels 1150. Figure 1 , for convenience, nine unit pixels 1150 are shown, but the present disclosure is not limited thereto. In order to realize a color image by using the display device 1000, each of the plurality of unit pixels 1150 may include pixels of different colors. For example, each unit pixel 1150 may include a first pixel 1151, a second pixel 1152, and a third pixel 1153 having different colors. For example, the first pixel 1151, the second pixel 1152, and the third pixel 1153 may be a blue pixel, a green pixel, and a red pixel, respectively. However, the present disclosure is not limited to this example.

[0072] The first pixel 1151, the second pixel 1152, and the third pixel 1153 may include a first LED device, a second LED device, and a third LED device that emit light of different wavelength bands, respectively. For example, when the first pixel 1151, the second pixel 1152, and the third pixel 1153 are blue pixels, green pixels, and red pixels, respectively, the first LED device, the second LED device, and the third LED device may be a blue LED device, a green LED device, and a red LED device, respectively. The first LED device, the second LED device, and the third LED device may include any one of the LED device 100, the LED device 200, and the LED device 300 according to the above-mentioned embodiment. For example, the first LED device, the second LED device, and the third LED device may be the LED device 100, the LED device 200, and the LED device 300 according to the above-mentioned embodiment, respectively, and therefore will not be described in detail.

[0073] The first pixel 1151, the second pixel 1152, and the third pixel 1153 may include a plurality of LED devices emitting light of the same wavelength band. For example, when the first pixel 1151, the second pixel 1152, and the third pixel 1153 are respectively a blue pixel, a green pixel, and a red pixel, the first pixel 1151, the second pixel 1152, and the third pixel 1153 may include blue LED devices, respectively. In this case, the second pixel 1152 as a green pixel may further include a green conversion layer that converts blue light into green light, and the third pixel 1153 as a red pixel may further include a red conversion layer that converts blue light into red light.

[0074] For example, when the first pixel 1151, the second pixel 1152, and the third pixel 1153 are blue pixels, green pixels, and red pixels, respectively, the first pixel 1151, the second pixel 1152, and the third pixel 1153 may include ultraviolet LED devices, respectively. In this case, the first pixel 1151 as a blue pixel may further include a blue conversion layer that converts ultraviolet light into blue light, the second pixel 1152 as a green pixel may further include a green conversion layer that converts ultraviolet light into green light, and the third pixel 1153 as a red pixel may further include a red conversion layer that converts ultraviolet light into red light.

[0075] Figures 5 to 16 is a diagram for describing a method of manufacturing an LED device according to an example embodiment, Fig.17 is a diagram for describing a method of manufacturing an LED device according to another example embodiment.

[0076] Reference Figure 5 , a sacrificial pattern 451 may be formed on the top surface of the substrate 450. Here, when the light emitting layer ( Figure 8When the substrate 410 includes a nitride semiconductor, the substrate 450 may include, for example, a sapphire substrate. However, this is only an example, and the substrate 450 may include a silicon substrate, a silicon carbide (SiC) substrate, a gallium arsenide (GaAs) substrate, etc., as well as various other materials.

[0077] The sacrificial pattern 451 may include, for example, a photoresist, a nanoimprint resin, organic nanoparticles, etc. The sacrificial pattern 451 may be formed using methods such as a photolithography method, a nanoimprint method, organic nanoparticle attachment, etc. The sacrificial pattern 451 may be formed in various forms as needed. For example, the sacrificial pattern 451 may be formed in a form extending in one direction or in other various forms.

[0078] Reference Figure 6 , a film material layer 452' is formed on the top surface of the substrate 450 to cover the sacrificial pattern 451. The film material layer 452' may define a cavity ( Figure 7 453), and can be formed within a temperature range where the sacrificial pattern 451 does not deform. The film material layer 452' can be formed to a thickness such that after the sacrificial pattern 451 is removed, the original shape of the structure (eg, composed of the film material layer 452') remains stable.

[0079] The film material layer 452' may be formed using various methods such as atomic layer deposition (ALD), wet synthesis, metal deposition and oxidation, sputtering, etc. In this case, the film material layer 452' may be formed in an amorphous form or in a fine-grained polycrystalline form.

[0080] The film material layer 452' may include, for example, aluminum oxide (Al 2 O 3 However, this is only an example, and the film material layer 452' may include but is not limited to silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), zirconium oxide (ZrO 2 ), yttrium oxide (Y 2 O 3 )-zirconium oxide, copper oxide (CuO,Cu 2 O), Tantalum Oxide (Ta 2 O 5 ), aluminum nitride (AlN), silicon nitride (Si 3 N 4 )wait.

[0081] Reference Figure 7, the sacrificial pattern 451 is selectively removed from the substrate 450. The sacrificial pattern 451 may be removed using heating, ashing, or an organic solvent. Once the sacrificial pattern 451 is removed, a cavity 453 defined by the substrate 450 and the film material layer 452' may be formed.

[0082] As described above, the film material layer 452' is generally formed in an amorphous form or in a polycrystalline form with very small particles. After removing the sacrificial pattern 451, the film material layer 452' can be crystallized by heat treatment to form the film 452. Here, the legs of the film 452 can be provided on opposite sides of the cavity 453 to contact the substrate 450.

[0083] For example, when the substrate 450 and the film material layer 452' have the same composition as each other, as when the substrate 450 includes a sapphire substrate and the film material layer 452' includes aluminum oxide, the film 452 can be formed by crystallizing the film material layer 452' into the same crystal structure as the substrate 450 by means of heat treatment at about 1000° C. This is because, since solid phase epitaxy occurs in a portion of the film material layer 452' that is in direct contact with the substrate 450 during the high-temperature heat treatment, crystallization occurs along the crystallographic direction of the substrate 450.

[0084] The film 452 formed by crystallization may be formed in a polycrystalline form including large grains or in a single crystal form. In a subsequent process, when an epitaxial layer of a nitride semiconductor is grown, the film 452 on the cavity 453 serves as a seed layer and thus needs to be crystallized in advance.

[0085] Reference Figure 8 , a first semiconductor layer 411, an active layer 413, and a second semiconductor layer 412 are sequentially grown on the film 452 above the cavity 453, thereby forming a light emitting layer 410. Here, the first semiconductor layer 411, the active layer 413, and the second semiconductor layer 412 may be grown, for example, using chemical vapor deposition (CVD). More specifically, the first semiconductor layer 411, the active layer 413, and the second semiconductor layer 412 may be grown by organic metal CVD (metal organic CVD: MOCVD).

[0086] The light emitting layer 410 may be formed to have a core-shell structure. In this case, the first semiconductor layer 411 may constitute a core of the core-shell structure, and the active layer 413 and the second semiconductor layer 412 may constitute a shell of the core-shell structure.

[0087] The first semiconductor layer 411, the active layer 413, and the second semiconductor layer 412 constituting the light emitting layer 410 may include, for example, a nitride semiconductor. Here, the nitride semiconductor may include, but is not limited to, for example, GaN, InN, AlN, or a combination thereof. By adjusting the band gap according to the type of material constituting the light emitting layer 410, light of a desired wavelength band may be emitted. For example, the light emitting layer 410 may emit red light, green light, or blue light.

[0088] According to an example embodiment, a first semiconductor layer 411 may be grown on the film 452 above the cavity 453. The first semiconductor layer 411 may include, but is not limited to, an n-type nitride semiconductor. For example, the first semiconductor layer 411 may include n-GaN. By adjusting the growth time, the first semiconductor layer 411 may be formed in a 3D shape having a relatively thick thickness on the film 452 on the cavity 453. The first semiconductor layer 411 may have a single layer or a multi-layer structure.

[0089] According to an example embodiment, an active layer 413 may be grown on the first semiconductor layer 411. The active layer 413 may be formed to cover the top surface and the side surface of the first semiconductor layer 411. It will be understood that the terms such as "top surface" and "bottom surface" used herein are described based on the orientation of the elements in the figure. The active layer 413 may generate light of a specific color by recombination between electrons and holes, and may have an MQW structure. However, the present disclosure is not limited thereto, and the active layer 113 may have an SQW structure as the case may be. For example, the active layer 113 may include GaN.

[0090] According to an example embodiment, a second semiconductor layer 412 may be grown on the active layer 413. The second semiconductor layer 412 may include, but is not limited to, a p-type nitride semiconductor. For example, the second semiconductor layer 412 may include p-GaN. The second semiconductor layer 412 may have a single layer or a multi-layer structure.

[0091] The film 452 may relieve stress that may cause dislocation together with the light emitting layer 410 grown on the film, so that the light emitting layer 410 grown on the film may have high quality with low defect density.

[0092] In general, stress caused by the physical difference between the growth substrate and the thin film grown on the growth substrate can be converted into elastic energy on the interface and can become a driving force for generating dislocations. In the case of the prior art, the growth substrate has a much greater thickness than the thin film and is difficult to deform, so that dislocations are generated on the thin film. However, as in the example embodiment, when the film 452 is thinner than the light emitting layer 410, the generation of dislocations on the light emitting layer 410 is reduced, so that a high-quality light emitting layer 410 with a low defect density can be formed.

[0093] In this example embodiment, since there is a cavity 453 between the substrate 450 and the light emitting layer 410, regardless of the difference in thermal expansion coefficient between the substrate 450 and the light emitting layer 410, stress energy can also be consumed through the deformation of the cavity 453, thereby reducing the thermal stress applied to the light emitting layer 410 and also reducing the bending of the substrate 450.

[0094] In this way, a light emitting layer 410 having excellent physical properties can be formed on the film 452 on the cavity 453, thereby realizing an LED device having high efficiency and high reliability ( Fig.15 of 400) and improve light extraction efficiency.

[0095] Reference Fig. 9 , the passivation layer 420 may be formed on the surface of the light emitting layer 410. Here, the passivation layer 420 may be formed to cover the surfaces of the first semiconductor layer 411, the active layer 413, and the second semiconductor layer 412 exposed to the outside. The passivation layer 420 may be formed by depositing, for example, silicon oxide or silicon nitride on the surface of the light emitting layer 410 using, for example, atomic layer deposition (ALD) or CVD. Fig.10 By etching the top of the passivation layer 420 , a portion 412 a of the top surface of the second semiconductor layer 412 may be opened.

[0096] Reference Fig.11 , a photoresist 460 is formed on the substrate 450 and patterned to open the top of the passivation layer 420. Then, the second electrode 440 may be formed on the passivation layer 420 to contact the open portion 412a of the second semiconductor layer 412. Here, the second electrode 440 may include a reflective electrode. When the second semiconductor layer 412 includes a p-type nitride semiconductor, the second electrode 440 may include a p-type electrode. The second electrode 440 may be formed by depositing a metal material having excellent conductivity on the top surface of the passivation layer 420 using, for example, electron beam deposition, etc. Thereafter, the photoresist 460 may be removed.

[0097] Reference Fig.12 , the adhesive layer 471 of the separation member 470 adheres to the top surface of the second electrode 440. Next, referring to Fig.13 , by applying mechanical force to the separation member 470, the leg portion of the film 452 may collapse, thereby separating the light emitting layer 410 from the substrate 450. In this case, as Fig.13 As shown, the film 452 on the bottom surface of the first semiconductor layer 411 remains intact.

[0098] The substrate 450 and the light emitting layer 410 may be connected to each other through the film 452 with the cavity 453 therebetween. Here, the legs of the film 452 may collapse with only a small mechanical force, so that the light emitting layer 410 may be easily separated from the substrate 450 without being damaged.

[0099] Reference Fig.14 , the film 452 remaining on the bottom surface of the first semiconductor layer 411 may be removed. For example, when the film 452 includes aluminum oxide, phosphoric acid (H 3 PO 4 ) to remove the film 452, but this is only an example. As the film 452 is removed, a portion 411a of the bottom surface of the first semiconductor layer 411 is opened. The separation member 470 can be separated from the second electrode 440.

[0100] Reference Fig.15 , the first electrode 430 may be formed on the bottom surface of the passivation layer 420 to contact the opened portion 411a of the first semiconductor layer 411. Thus, the LED device 400 may be completed. Here, the first electrode 430 may include a transparent electrode. When the first semiconductor layer 411 includes an n-type nitride semiconductor, the first electrode 430 may include an n-type electrode. The first electrode 430 may be formed by depositing a transparent conductive material such as ITO, IZO, etc. on the bottom surface of the passivation layer 420 using, for example, electron beam deposition, etc.

[0101] The LED device 400 completed as described above may have a size of, for example, about 100 μm×100 μm or less and a thickness of about 10 μm or less. However, this is only an example.

[0102] Reference Fig.16 , a transparent substrate 480 having a transparent electrode 481 thereon may be provided below the LED device 400. According to an example embodiment, the transparent electrode 481 may be deposited on the transparent substrate 480. The transparent electrode 481 may be provided to be electrically connected to the first electrode 430. Here, when a plurality of LED devices 400 are manufactured, the transparent electrode 481 may be used as a common electrode electrically connected to the first electrode 430.

[0103] According to another exemplary embodiment, in the Fig.14 After the open portion 411a of the first semiconductor layer 411 is formed, the concavo-convex structure for improving the light extraction efficiency may be as follows: Fig.17As shown, the concave-convex structure is formed on the open portion 411a of the first semiconductor layer 411. Here, the concave-convex structure may include a plurality of protrusions 411a', each of which may have, but is not limited to, a polygonal trumpet shape or a conical shape. The concave-convex structure may be formed by wet etching the open (e.g., exposed) portion 411a of the first semiconductor layer 411 using, for example, tetramethylammonium chloride (TMAH), potassium hydroxide (KOH), or the like.

[0104] According to the aforementioned exemplary embodiment, the light emitting layer 410 is grown on the film 452, which is spaced apart from the substrate 450 and has the cavity 453 therebetween, so that a high-quality LED device 400 with a low defect density can be manufactured. Since the light emitting layer 410 can be easily separated from the substrate 450 without being damaged by only a small mechanical force, the features shown in the various exemplary embodiments of the present disclosure can be useful for application fields that require separation between the substrate 450 and the light emitting layer 410 (e.g., manufacturing an LED device with a vertical electrode structure). In addition, since the end of the active layer 413 exposed on the bottom surface of the light emitting layer 410 can be covered by the passivation layer 420, the light extraction efficiency can be further improved.

[0105] Hereinafter, a method of manufacturing an LED device having a larger size than the LED device 400 manufactured according to the aforementioned embodiment will be described.

[0106] Figures 18 to 28 is a diagram for describing a method of manufacturing an LED device according to another example embodiment, Fig.29 is a diagram for describing a method of manufacturing an LED device according to another example embodiment, Fig.30 is a diagram for describing a method of manufacturing an LED device according to another example embodiment, Fig.31 is a diagram for describing a method of manufacturing an LED device according to another example embodiment.

[0107] Reference Fig.18 , a plurality of sacrificial patterns 551 may be formed on a top surface of the substrate 550 . Fig.18 The case where three sacrificial patterns 551 are formed on the top surface of the substrate 550 is shown, but the present disclosure is not limited thereto. Here, when the light emitting layer ( Fig.21 When the substrate 510 includes a nitride semiconductor, the substrate 550 may include, for example, a sapphire substrate. The sacrificial pattern 551 may be formed in various forms by using, for example, a photolithography method, a nanoimprint method, organic nanoparticle attachment, and the like.

[0108] Reference Fig.19, a film material layer 552' may be formed on the top surface of the substrate 550 to cover the sacrificial pattern 551. The film material layer 552' may be formed by using, for example, ALD, wet synthesis, metal deposition and oxidation, sputtering, etc. In this case, the film material layer 552' may be formed in an amorphous form or in a polycrystalline form with fine particles. For example, when the substrate 550 includes a sapphire substrate, the film material layer 552' may include aluminum oxide (Al 2 O 3 ).

[0109] Reference Fig. 20 , the sacrificial pattern 551 is selectively removed from the substrate 550. Once the sacrificial pattern 551 is removed, a cavity 553 defined by the substrate 550 and the film material layer 552' may be formed.

[0110] After the sacrificial pattern 551 is removed, the film material layer 552 ′ is crystallized by heat treatment, thereby forming a film 552 having a plurality of protruding portions corresponding to the cavities 553 . Fig. 20 The case where three cavities 553 corresponding to the three sacrificial patterns 551 and three protruding portions of the film 552 are formed is shown. The film 552 formed by crystallization may be formed in a polycrystalline form including large grains or in a single crystal form. On opposite sides of each cavity 553, legs of the film 552 may be provided to contact the substrate 550.

[0111] Reference Fig.21 , a first semiconductor layer 511, an active layer 513, and a second semiconductor layer 512 are sequentially grown on the film 552 on the cavity 553, thereby forming a light emitting layer 510. Here, for example, the first semiconductor layer 511, the active layer 513, and the second semiconductor layer 512 may be grown by MOCVD, but is not limited thereto.

[0112] The light emitting layer 510 may be formed to have a core-shell structure. In this case, the first semiconductor layer 511 may constitute the core of the core-shell structure, and the active layer 513 and the second semiconductor layer 512 may constitute the shell of the core-shell structure. The first semiconductor layer 511, the active layer 513, and the second semiconductor layer 512 constituting the light emitting layer 510 may include, for example, nitride semiconductors. By adjusting the band gap according to the type of material constituting the light emitting layer 510, light of a desired wavelength band may be emitted.

[0113] According to an example embodiment, a first semiconductor layer 511 may be grown on the film 552 on the cavity 553. Here, by adjusting the growth time, nitride semiconductors are grown on three protruding portions of the film 552, respectively, and connected to each other, thereby forming the first semiconductor layer 511. The first semiconductor layer 511 may have a 3D shape by being formed to a relatively thick thickness. The first semiconductor layer 511 may include, but is not limited to, an n-type nitride semiconductor.

[0114] According to an example embodiment, an active layer 513 may be grown on the first semiconductor layer 511. The active layer 513 may be formed to cover the top surface and side surfaces of the first semiconductor layer 511. A second semiconductor layer 512 may be grown on the active layer 513. The second semiconductor layer 512 may include, but is not limited to, a p-type nitride semiconductor.

[0115] The film 552 and the light emitting layer 510 grown on the film 552 can relieve stress that may cause dislocations, so that the light emitting layer 510 grown on the film 552 can have high quality with low defect density. Since the cavity 553 is between the substrate 550 and the light emitting layer 510, the thermal stress applied to the light emitting layer 510 can be reduced.

[0116] Reference Fig. 22 , a passivation layer 520 may be formed on the surface of the light emitting layer 510. Here, the passivation layer 520 may be formed to cover the surfaces of the first semiconductor layer 511, the active layer 513, and the second semiconductor layer 512 that are exposed to the outside. The passivation layer 520 may be formed by, for example, ALD or CVD. Here, the passivation layer 520 may not be formed on the portion of the bottom surface of the first semiconductor layer 511 between the films 552. However, the present disclosure is not limited to this example, and the passivation layer 520 may also be formed on the portion of the bottom surface of the first semiconductor layer 511 between the films 552 depending on the deposition method. Next, by etching the top of the passivation layer 520, a portion 512a of the top surface of the second semiconductor layer 512 may be opened.

[0117] Reference Fig.23 , a photoresist 560 is formed on the substrate 550 and patterned to open the top of the passivation layer 520. Then, the second electrode 540 may be formed on the passivation layer 520 to contact the open portion 512a of the second semiconductor layer 512. Here, the second electrode 540 may include a reflective electrode. When the second semiconductor layer 512 includes a p-type nitride semiconductor, the second electrode 540 may include a p-type electrode. Thereafter, the photoresist 560 may be removed.

[0118] Reference Fig.24 , the adhesive layer 571 of the separation member 570 adheres to the top surface of the second electrode 540. Next, referring to Fig.25 , by applying a mechanical force to the separation member 570, the leg portion of the film 552 may collapse, thereby separating the light emitting layer 510 from the substrate 550. In this case, the film 552 on the bottom surface of the first semiconductor layer 511 may remain intact. Therefore, a portion 511a of the bottom surface of the first semiconductor layer 511 between the films 552 may be exposed to the outside.

[0119] Reference Fig.26 , the film 552 remaining on the bottom surface of the first semiconductor layer 511 may be removed. As the film 552 is removed, a portion 511 b of the bottom surface of the first semiconductor layer 511 may be opened. The separation member 570 may be separated from the second electrode 540 .

[0120] Reference Fig. 27 , the first electrode 530 may be formed on the bottom surface of the passivation layer 520 to contact the opened portion 511b of the first semiconductor layer 511. Thus, the LED device 500 may be completely manufactured. Here, the first electrode 530 may include a transparent electrode. When the first semiconductor layer 511 includes an n-type nitride semiconductor, the first electrode 530 may include an n-type electrode.

[0121] In this example embodiment, the light emitting layer 510 may be grown by using the film 552 having a plurality of protruding portions, thereby manufacturing the LED device 500 having a larger size than the LED device 400 manufactured according to the above-described example embodiment.

[0122] Reference Fig.28 , a transparent substrate 580 having a transparent electrode 581 may be provided under the LED device 500. According to an example embodiment, the transparent electrode 581 may be deposited on the transparent substrate 580. The transparent electrode 581 may be provided to be electrically connected to the first electrode 530. Here, when a plurality of LED devices 500 are manufactured, the transparent electrode 581 may be used as a common electrode electrically connected to the first electrode 530.

[0123] According to another example embodiment, referring to Fig.29 , in such Fig.25 After the film 552 on the bottom surface of the first semiconductor layer 511 shown remains intact so that a portion 511a of the bottom surface of the first semiconductor layer 511 between the films 552 is opened, a first electrode 530 can be formed on the bottom surface of the passivation layer 520 to contact the opened portion 511a of the first semiconductor layer 511, thereby manufacturing an LED device 500'.

[0124] According to another example embodiment, referring to Fig.30 , as mentioned above Fig.26 After forming the open portion 511b of the first semiconductor layer 511, a concavo-convex structure for improving light extraction efficiency may be formed on the open portion 511b of the first semiconductor layer 511. Here, the concavo-convex structure may include a plurality of protrusions 511a'. The concavo-convex structure may be formed by wet etching the open portion 511b of the first semiconductor layer 511.

[0125] According to another example embodiment, referring to Fig.31 , in such Fig.25After the film 552 on the bottom surface of the first semiconductor layer 511 is kept intact so that the portion 511a of the bottom surface of the first semiconductor layer 511 between the films 552 is opened, a concavo-convex structure for improving light extraction efficiency may be formed on each of the opened portions 511a of the first semiconductor layer 511. Here, the concavo-convex structure may include a plurality of protrusions 511a'. The concavo-convex structure may be formed by wet etching the opened portion 511a of the first semiconductor layer 511.

[0126] According to the aforementioned example embodiments, since the light-emitting layer is grown on the crystallized film, which is spaced apart from the substrate and has a cavity therebetween, the stress that may be generated in the light-emitting layer can be reduced, thereby forming a high-quality light-emitting layer with a low defect density. Therefore, an LED device with high efficiency and high reliability and improved light extraction efficiency can be realized. In addition, a passivation layer is provided to cover the end of the active layer on the top surface of the light-emitting layer, thereby improving the current injection characteristics and thus improving the light extraction efficiency. In addition, by forming a concave-convex structure on the top surface of the light-emitting layer as a light extraction surface, the light extraction efficiency can be further improved. Although the aforementioned embodiments of the present disclosure have been described, it will be apparent to those of ordinary skill in the art that these embodiments are examples and various modifications can be made thereto.

[0127] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2019-0153553 filed in the Korean Intellectual Property Office on November 26, 2019, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A light emitting diode device, comprising: A light-emitting layer, comprising a first semiconductor layer, an active layer and a second semiconductor layer, wherein the light-emitting layer has a core-shell structure; a passivation layer provided to cover a portion of a top surface of the first semiconductor layer and a portion of a bottom surface of the second semiconductor layer; a first electrode provided on a first side of the light emitting layer to contact the first semiconductor layer; as well as a second electrode provided on a second side of the light emitting layer to contact the second semiconductor layer, The light emitting layer is formed on a film material layer on a substrate, and a cavity is defined between the film material layer and the substrate.

2. The light emitting diode device according to claim 1, wherein the first semiconductor layer is provided in a three-dimensional shape, wherein the active layer is provided to cover the bottom surface and the side surfaces of the first semiconductor layer, and The second semiconductor layer is provided on the active layer. 3 . The light emitting diode device according to claim 2 , wherein the passivation layer is provided to cover the entire side surface of the light emitting layer, a first portion of the top surface of the first semiconductor layer, and a first portion of the bottom surface of the second semiconductor layer.

4. The light emitting diode device according to claim 3, wherein the first electrode is provided to contact a second portion of the top surface of the first semiconductor layer, the second portion of the top surface is at a first opening in the passivation layer, and the second electrode is provided to contact a second portion of the bottom surface of the second semiconductor layer, the second portion of the bottom surface is at a second opening in the passivation layer. 5 . The light emitting diode device according to claim 4 , wherein the first electrode comprises a transparent electrode, and the second electrode comprises a reflective electrode. The light emitting diode device according to claim 4 , wherein the second portion of the top surface of the first semiconductor layer comprises a concavo-convex structure for improving light extraction. 7 . The light emitting diode device of claim 1 , wherein the first semiconductor layer, the active layer, and the second semiconductor layer include nitride semiconductor materials.

8. A display device, comprising: Multiple pixels, arranged two-dimensionally to emit light of different colors, wherein the plurality of pixels comprises a plurality of light emitting diode devices, Each of the plurality of light emitting diode devices comprises: A light-emitting layer, comprising a first semiconductor layer, an active layer and a second semiconductor layer, wherein the light-emitting layer has a core-shell structure; a passivation layer provided to cover a portion of a top surface of the first semiconductor layer and a portion of a bottom surface of the second semiconductor layer; A first electrode provided on a first side of the light emitting layer to contact the first semiconductor layer; and A second electrode is provided on a second side of the light emitting layer to contact the second semiconductor layer, wherein the light emitting layer is formed on a film material layer formed on a substrate, and a cavity is defined between the film material layer and the substrate.

9. The display device according to claim 8, wherein the first semiconductor layer is provided in a three-dimensional shape, wherein the active layer is provided to cover the bottom surface and the side surfaces of the first semiconductor layer, and The second semiconductor layer is provided on the active layer. 10 . The display device of claim 9 , wherein the passivation layer is provided to cover an entire side of the light emitting layer, a first portion of the top surface of the first semiconductor layer, and a first portion of the bottom surface of the second semiconductor layer. 11 . The display device of claim 10 , wherein a second portion of the top surface of the first semiconductor layer at the opening in the passivation layer comprises a concavo-convex structure for improving light extraction. 12 . The display device according to claim 8 , wherein the plurality of pixels include a plurality of light emitting diode devices emitting light of different wavelength bands. 13 . The display device according to claim 8 , wherein the plurality of pixels include a plurality of light emitting diode devices emitting light of the same wavelength band. The display device according to claim 13 , wherein the plurality of pixels comprises a plurality of blue light emitting diode devices. 15 . The display device according to claim 14 , wherein one or more first pixels among the plurality of pixels further include a green conversion layer that converts blue light into green light, and one or more second pixels among the plurality of pixels further include a red conversion layer that converts blue light into red light.

16. A method for manufacturing a light emitting diode device, the method comprising: A film is formed on a substrate, wherein the forming of the film comprises: forming a sacrificial pattern on the substrate; forming a film material layer on the substrate to cover the sacrificial pattern; removing the sacrificial pattern to form a cavity between the film material layer and the substrate; and crystallizing the film material layer; forming a light emitting layer by sequentially depositing a first semiconductor layer having a three-dimensional shape, an active layer covering the top surface and side surfaces of the first semiconductor layer, and a second semiconductor layer covering the active layer on the film; forming a passivation layer to cover the light emitting layer, the passivation layer covering a portion of a top surface of the first semiconductor layer and a portion of a bottom surface of the second semiconductor layer; and A first electrode and a second electrode are formed to contact the first semiconductor layer and the second semiconductor layer, respectively.

17. The method according to claim 16, further comprising: A first opening is formed in the passivation layer at a portion of a top surface of the light emitting layer by etching the passivation layer.

18. The method according to claim 17, further comprising: By removing the film, a second opening is formed in the passivation layer at a portion of the bottom surface of the first semiconductor layer.

19. The method according to claim 18, further comprising: Before forming the first electrode, a concavo-convex structure is formed on the portion of the bottom surface of the first semiconductor layer.

20. A light emitting diode device, comprising: A light-emitting layer having a core-shell structure, the light-emitting layer comprising: a first semiconductor layer having a first surface through which light is emitted; an active layer formed adjacent to the first semiconductor layer, the active layer surrounding a second surface, a third surface, and a fourth surface of the first semiconductor layer, the second surface being opposite to the first surface, the third surface and the fourth surface being side surfaces of the first semiconductor layer; and a second semiconductor layer formed adjacent to the active layer; a passivation layer provided to cover the light emitting layer, including an end portion of the active layer at the first surface of the first semiconductor layer, the passivation layer including a first opening at a first portion on the first surface of the first semiconductor layer and a second opening at a second portion on the first surface of the second semiconductor layer; A first electrode provided in the first opening to contact the first semiconductor layer; and a second electrode provided in the second opening to contact the second semiconductor layer, The light emitting layer is formed on a film material layer on a substrate, and a cavity is defined between the film material layer and the substrate.

21. The light emitting diode device according to claim 20, further comprising: A plurality of protrusions are formed on the first surface of the first semiconductor layer at the first opening.

22. The light emitting diode device of claim 21, wherein the plurality of protrusions are separated by one or more films.

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