Light-emitting devices

Abstract

The present invention relates to a light-emitting device comprising a semiconductor stack having a first layer of a first doping type, a second layer of a second doping type, and an active region disposed between the first and second layers. The light-emitting device further comprises a first electrical contact connected to an electrical contact via, the electrical contact via extending electrically insulated through the second layer and the active region and contacting the first layer, and a second electrical contact contacting the second layer, the first and second electrical contacts being disposed in the second layer on the bottom surface of the semiconductor stack. A converter layer configured to convert light of a first wavelength generated in the active region to light of a second wavelength is disposed in the first layer on the top surface of the semiconductor stack. The interface between the first layer and the converter layer is roughened over an area smaller than the area of ​​the top surface, particularly over an area at least 10% smaller than the area of ​​the top surface.

Description

[Technical Field]

[0001] This application claims priority from German Patent Application No. 10 2022 125 869.6, filed October 6, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a light emitting device, in particular a pitch of micro LEDs or micro LEDs with a common converter layer disposed thereon, which light emitting device provides improved contrast performance of emitted light per pixel and reduced crosstalk between adjacent pixels compared to known light emitting devices. [Background technology]

[0003] As the size of light-emitting devices shrinks due to the desire to provide displays with increasingly higher resolution, and thus increasingly reduced pixel pitches (typically less than 40 μm), crosstalk between adjacent pixels can increase significantly, for example, due to light diffusing through a converter layer disposed on top of the light-emitting device and / or insufficient contrast performance of the pixels. This is because complete singulation of separate pixels of a light-emitting device, which is typically easily achieved up to the epitaxial layer, cannot be achieved through a converter layer disposed on top of the light-emitting device when pixels with a pitch of less than 40 μm are considered. Therefore, in this size range, the converter layer must remain unsingulated due to manufacturing limitations, so that the converter layer covers several pixels as a common converter or protrudes from each pixel. However, unsingulated converter layers that cover several pixels as a common converter or protrude from each pixel can result in the above-mentioned crosstalk and insufficient contrast performance.

[0004] Furthermore, light-emitting devices with pixels arranged in an array with a pitch of less than 40 μm (e.g., stitching small "monolithic" pixels together in a 5×5 pixel array) tend to have illumination non-uniformities between the "inner" and "rim" pixels at the stitching trench.

[0005] It is therefore an object of the present application to counteract at least one of the above-mentioned problems and to provide a light emitting device with enhanced contrast performance. Summary of the Invention

[0006] These and other objects are addressed by the subject matter of the independent claims. Features and further aspects of the proposed principle are set out in the dependent claims.

[0007] The inventors propose a method to physically reduce the area through which light escapes from the epitaxial structure of a pixel of a light-emitting device, for example, into the environment or converter layer, by introducing outcoupling textures only within the central region of the interface between the pixel's epitaxial surface and the environment or converter layer. This effectively limits the area through which light escapes from the pixel without actually reducing the physical area through which current flows, thereby avoiding problems associated with current crowding. This approach therefore makes it easier to meet forward voltage requirements and avoids current crowding effects that can occur when physically reducing pixel size, which can significantly reduce internal quantum efficiency (IQE). Even selective texturing of the central region of the interface between the pixel's epitaxial surface and the environment or converter layer provides greater flexibility in ensuring illumination uniformity in pixel arrays constructed by stitching together sets of multiple pixels.

[0008] In one embodiment, a light-emitting device is provided that includes a semiconductor stack having a first layer of a first doping type, a second layer of a second doping type, and an active region disposed between the first and second layers. The light-emitting device further includes a first electrical contact connected to an electrical contact via, the electrical contact via extending electrically insulated through the second layer and the active region and contacting the first layer, and a second electrical contact contacting the second layer, the first and second electrical contacts being disposed in the second layer on a bottom surface of the semiconductor stack. To provide an area through which light escapes from the semiconductor stack to the environment or, for example, into a converter layer, that is smaller than the area of ​​the top surface of the semiconductor stack, the interface between the first layer and a medium above the top surface of the semiconductor stack is roughened over an area smaller than the area of ​​the top surface, particularly over an area at least 10% smaller than the area of ​​the top surface. This effectively limits the area through which light escapes from the semiconductor stack into the medium, for example the environment or the converter layer, improving the contrast performance of the light emitting device.

[0009] In some embodiments, the medium is a converter layer disposed in a first layer on top of the semiconductor stack, the converter layer configured to convert light of a first wavelength generated in the active region to light of a second wavelength, although the medium may be the environment surrounding the light emitting device, such as air.

[0010] The roughened interface may, for example, be located away from the periphery of the top surface, and in particular in a central area above the active region, although in this context the term "central" area should not be understood to mean that the roughened interface is located at the very center of the top surface, but may be located away from the periphery of the top surface, for example at different distances, for example to opposite edges of the top surface.

[0011] In some embodiments, the interface between the first layer and the environment or converter layer is roughened in a central area above the active region, the central area being at least 5%, 10%, or 15% smaller than the protrusion of the active region when viewed in a direction perpendicular to the top surface.

[0012] In some embodiments, the roughened interface provides better extraction of light generated in the active region from the top surface into the environment or converter layer compared to the non-roughened interfaces surrounding the roughened interface. This effectively limits the area through which light escapes from the semiconductor stack into the environment or converter layer. The non-roughened interface can simultaneously act as a reflector, particularly for light incident on the top surface at shallow angles, due to the difference in refractive index between the semiconductor stack and the environment or converter layer. This can further enhance the effect of limiting the area through which light escapes from the semiconductor stack into the environment or converter layer.

[0013] To further enhance the effect of limiting the area through which light escapes from the semiconductor stack into the environment or the converter layer, a coating may be disposed on the top surface surrounding the roughened interface, the coating having a higher transmission for light incident on the coating perpendicular to the top surface than for light incident on the coating at a shallower angle relative to the top surface. In particular, the coating may be configured to transmit light incident on the coating perpendicular to the top surface and absorb or reflect light incident on the coating at a shallower angle relative to the top surface, suppressing light emission "to the sides" of the light-emitting device, but transmitting light emission in a direction substantially perpendicular to the top surface. This also effectively limits the area through which light escapes from the semiconductor stack into the environment or the converter layer, improving the contrast performance of the light-emitting device.

[0014] In some embodiments, a reflective sidewall is disposed on at least one side of the semiconductor stack, connecting the top and bottom surfaces. The reflective sidewall or reflective sidewalls may particularly surround / enclose the semiconductor stack and thus may be disposed on all sides of the semiconductor stack. The reflective sidewall may be configured to reflect light generated in the active region toward the top surface, thereby increasing the light-emitting efficiency of the light-emitting device. The reflective sidewall may also be configured to reflect light reflected by a non-roughened surface or coating back to a roughened surface, thereby again increasing the light-emitting efficiency of the light-emitting device, and to ensure that light initially blocked by a non-roughened surface or coating nevertheless finds its way out of the light-emitting device through the roughened interface.

[0015] In some embodiments, a reflective layer is disposed on the bottom surface of the layer stack, the reflective layer surrounding the first and second electrical contacts. The reflective layer can be configured to reflect light generated in the active region toward the top surface, increasing the light-emitting efficiency of the light-emitting device. The reflective layer can also be configured to reflect light reflected from an unroughened surface or coating back to the roughened surface, thereby again increasing the light-emitting efficiency of the light-emitting device, and to ensure that light initially blocked by an unroughened surface or coating nevertheless finds its way out of the light-emitting device through the roughened interface.

[0016] In particular, improving the reflectivity of the sidewalls and / or the bottom surface of the semiconductor stack can minimize the potential output luminance penalty compared to providing an outcoupling structure across the entire top surface of the light-emitting device. The reflectivity of the reflective sidewalls and / or reflective layer can be improved, for example, by selecting a less lossy material for the sidewalls (e.g., aluminum or silver) and applying a single-layer coating (e.g., SiO2) thick enough to allow total internal reflectance with minimal loss. Alternatively, multi-layer coatings that function as distributed Bragg mirrors can be applied to improve reflectance across all angles of incidence.

[0017] In some embodiments, the at least second layer and the active region are separated into a first portion and at least a second portion of the semiconductor stack, respectively, that form pixels of the light-emitting device. The first portion and at least a second portion can be formed, in particular, by trenches etched into the semiconductor stack, the trenches extending through the at least second layer and the active region, and optionally through a portion of the first layer or through the entire first layer. The first portion and at least a second portion can be arranged adjacent to one another, in particular, and, if there are more than two portions, can be arranged in an array corresponding to the pixel pitch of the light-emitting device. In some embodiments, the trenches can be filled with a reflective separator. The reflective separator can be similar to the sidewalls described above.

[0018] However, the first portion and at least the second portion may be separated by an electrical contact via, whereby the electrical contact via fills the trench separating the first portion and at least the second portion from one another. When the first portion and at least the second portion are separated by an electrical contact via, the trench may, in a preferred embodiment, extend through the second layer and the active region, as well as through a portion of the first layer, such that the electrical contact via contacts the first layer. Thus, the first layer may not be completely separated, but may comprise a portion connecting the first portion and at least the second portion of the semiconductor stack, providing a common electrical contact for portions of the layer stack.

[0019] In some embodiments, above each of the first and at least second portions, the interface between the first layer and the environment or the converter layer is roughened in distinct areas that are spaced apart from one another, in other words, each pixel of the light emitting device is associated with its own roughened interface area that limits the area through which light escapes from each pixel of the light emitting device into the environment or the common converter layer, thereby improving the contrast performance of the light emitting device.

[0020] In some embodiments, the upper surface is theoretically divided into surface areas, each of which is assigned to a first portion and at least a second portion, and the individual roughened interface areas are each located within the theoretically divided surface areas, each spaced apart from the periphery of the respective surface areas.

[0021] In some embodiments, the individual roughened interface areas are further away from adjacent edges of adjacent surface areas than from the opposing edges of the respective surface areas. In particular, the individual roughened interface areas are further away from the "inner" edges of the surface areas than from the "outer" edges of the surface areas, and the "outer" edges of the surface areas are closer to the sides of the semiconductor stack than the "inner" edges. This results in more uniform pixel illumination across the "inner" pixels as well as the "edge" pixels of the light-emitting device.

[0022] In some embodiments, each of the second electrical contacts contacts a separate portion of the second layer of the first portion and at least the second portion. Thus, each pixel of the light-emitting device has its own separate electrical contact on one side of the semiconductor stack and, in particular, a common electrical contact on the other side of the semiconductor stack. Thus, each pixel of the light-emitting device may be individually electrically controllable.

[0023] In some embodiments, the light-emitting device or pixel of the light-emitting device is formed by an LED, particularly an LED chip. In particular, the LED may be called a micro-LED. Micro-LEDs are small LEDs, for example, with edge lengths of less than 100 μm, particularly less than 40 μm, particularly in the range of 40 μm to 5 μm. Another range is between 100 μm and 10 μm. At these spatial dimensions, the optoelectronic semiconductor device is virtually invisible to the human eye.

[0024] In some embodiments, the micro LED or micro LED chip may be an unhoused semiconductor chip. Unhoused means that the chip does not have a package around its semiconductor layers, such as a "chip die." In some embodiments, unhoused may mean that the chip does not contain any organics. Thus, an unhoused device does not contain organic compounds that contain carbon in a covalent bond. [Brief explanation of the drawings]

[0025] Further aspects and embodiments in accordance with the proposed principles will become apparent in connection with the various embodiments and examples described in detail in conjunction with the accompanying drawings. [Figure 1] 1 shows a light emitting device having an extraction structure across the entire top surface of the light emitting device. [Figure 2] 1 shows a light emitting device according to some aspects of the proposed principles. [Figure 3] 1 shows another embodiment of a light emitting device according to some aspects of the proposed principles. [Figure 4] 1 shows further embodiments of light emitting devices according to some aspects of the proposed principles; [Figure 5A] 1 is a top view of an embodiment of a light emitting device according to some aspects of the proposed principles; [Figure 5B] 10A and 10B are top views of further embodiments of light-emitting devices according to some aspects of the proposed principles; DETAILED DESCRIPTION OF THE INVENTION

[0026] The following embodiments and examples disclose various aspects and combinations of various aspects according to the proposed principles. The embodiments and examples are not necessarily drawn to scale. Similarly, different elements may be shown in larger or smaller sizes to emphasize individual aspects. It goes without saying that the individual aspects of the illustrated embodiments and examples can be readily combined with one another without further ado without contradicting the principles of the present invention. Some aspects exhibit regular structures or shapes. It should be noted that in practice, slight variations or deviations from the ideal shapes may occur, but do not contradict the spirit of the present invention.

[0027] Also, the individual figures and aspects are not necessarily drawn to scale, and the proportions between individual elements are not necessarily correct. Some aspects are emphasized by showing them enlarged. However, terms such as "above," "over," "below," "under," "larger," "smaller," and the like are used accurately with respect to elements in the figures. Therefore, such relationships between elements can be inferred based on the figures.

[0028] Figure 1 shows a schematic diagram of a reference pixel of a light emitting device having an extraction structure over the entire top surface 11 of the semiconductor stack 2. Light L2 escaping from a converter layer 10 disposed in the semiconductor stack of the light emitting device at the edge of the pixel typically leaks into adjacent pixels (see L2 on the right of Figure 1), resulting in crosstalk between adjacent pixels and / or poor contrast performance of the pixel of the light emitting device.

[0029] However, if the light extraction into the converter layer 10 at the edges of the pixel can be minimized, the crosstalk between adjacent pixels will be reduced and therefore higher contrast performance of the pixel can be achieved.

[0030] Therefore, the inventors propose to limit the extraction structure at the interface between the semiconductor stack 2 and the converter layer to the central area above the pixel of the light-emitting device, so that light L2 is emitted from the light-emitting device only in the central area of ​​the pixel of the light-emitting device.

[0031] 2 shows a respective light-emitting device 1 including a semiconductor stack 2 having a first layer 3 of a first doping type, a second layer 4 of a second doping type, and an active region 5 disposed between the first and second layers. The light-emitting device 1 further comprises a first electrical contact connected to an electrical contact via (both not shown here), which extends electrically insulated through the second layer 4 and the active region 5 and contacts the first layer 3. A second electrical contact 8 also contacts the second layer and is disposed on the second layer 4 on the bottom surface 9 of the semiconductor stack 2, as is the first electrical contact (not shown). A converter layer 10 is disposed on the first layer 3 on the top surface 11 of the semiconductor stack 2 and is configured to convert light of a first wavelength L1 generated in the active region 5 to light of a second wavelength L2.

[0032] In order to provide an area through which light escapes from the semiconductor stack 2 into the converter layer 10 that is smaller than the area of ​​the top surface 11 of the semiconductor stack 2, the interface 12 between the first layer 3 and the converter layer 10 is roughened in an area that is smaller than the area of ​​the top surface 11. This effectively limits the area through which light escapes from the semiconductor stack 2 into the converter layer 10, improving the contrast performance of the light-emitting device 1. The roughened interface 12 is particularly located away from the periphery 13 of the top surface 11, and particularly in the central area above the active region 5.

[0033] 2, by limiting the roughened interface 12 to an area smaller than the area of ​​the top surface 11, light L1 incident on the non-roughened interfaces surrounding the roughened interface 12 is reflected back into the semiconductor stack 2 and does not escape the converter layer 10 at the edge of the pixel of the illustrated light-emitting device 1 compared to the light-emitting device of FIG. 1. This is because, due to the difference in refractive index between the semiconductor stack 2 and the converter layer 10 at the non-roughened interface, the roughened interface 12 provides better extraction of light generated in the active region 5 from the top surface 11 into the converter layer 10 compared to the non-roughened interfaces surrounding the roughened interface 12. The non-roughened interface therefore acts as a reflector, especially for light incident on the top surface 11 at shallow angles.

[0034] However, to ensure that light reflected back at the non-roughened interface still escapes the light-emitting device, reflective sidewalls 15 on the side surfaces 16 of the semiconductor stack 2, as well as a reflective layer 17 disposed on the bottom surface 9 of the semiconductor stack 2, are provided to guide the light reflected back towards the roughened interface 12 (see arrow on the right in Figure 2).

[0035] FIG. 3 illustrates a further embodiment of light-emitting device 1, in addition to the embodiment of FIG. 2 , that includes a coating 14 on top surface 11 surrounding roughened interface 12. Coating 14 is more transmissive to light incident on coating 14 substantially perpendicular to top surface 11 (see left arrow in FIG. 3 ) than to light incident on coating 14 at a shallower angle relative to top surface 11 (see right arrow in FIG. 3 ). This further reduces “sideways” emission from light-emitting device 1 while allowing emission in a direction substantially perpendicular to top surface 11. This also effectively limits the area through which light escapes from semiconductor stack 2 into converter layer 10, improving the contrast performance of light-emitting device 1. Coating 14 can be a thin-film (multi-layer) coating to further improve contrast or light extraction by, for example, managing the optical response at the non-roughened interface, reducing transmittance in this region for a specific angle or wavelength range and increasing transmittance for another specific angle or wavelength range. Coating 14 may be, for example, an interference filter, a dichroic filter, or the like.

[0036] 4 shows a further embodiment of a light-emitting device comprising several pixels arranged side by side and a common converter layer 10 disposed on the pixels. Such a design may be called a "cloverleaf" design, where for example four pixels are connected to each other like a cloverleaf.

[0037] To form the pixels, the semiconductor stack 2, in particular the second layer 4, the active region 5 and part of the first layer 3, are separated into individual portions 2a, 2b, ... of the semiconductor stack 2, which each form a pixel of the light-emitting device 1. The individual portions 2a, 2b, ... may be formed, in particular, by trenches etched into the semiconductor stack 2, trenches extending through the second layer 4 and the active region 5, as well as through part of the first layer 3. Each individual portion 2a, 2b, ..., and therefore each pixel, comprises its own active region 5a, 5b, ... for generating light L1 when excited.

[0038] The individual portions 2a, 2b, ... are separated by electrical contact vias 7, which thus fill the trenches separating the portions 2a, 2b, ... from one another. The electrical contact vias thereby contact the first layer 3, which is not completely isolated but comprises portions connecting the individual portions 2a, 2b, ... of the semiconductor stack 2 and providing a common electrical contact for the portions 2a, 2b, ... of the semiconductor stack 2. The electrical contact vias 7 on the bottom surface 9 of the semiconductor stack 2 are provided with first electrical contacts that can control a pixel in combination with second electrical contacts 8a, 8b, ... on the bottom surface 9 of each of the individual portions 2a, 2b, ... of the semiconductor stack 2. Thus, each pixel of the light-emitting device 2 has its own individual second electrical contact 8a, 8b, ... on one side of the semiconductor stack 2 and a common electrical contact on the other side of the semiconductor stack 2. In this way, each pixel of the light-emitting device 1 is individually electrically controllable.

[0039] Above each individual portion 2 a, 2 b, ..., and thus above each pixel, the interface between the first layer 3 and the converter layer 10 is roughened in individual areas 12 a, 12 b, ..., and the roughened interface areas 12 a, 12 b, ... are spaced apart from one another. Thus, each pixel of the light-emitting device 1 is associated with its own roughened interface area 12 a, 12 b, ..., which limits the area through which light escapes from each pixel of the light-emitting device into the common converter layer 10, thereby improving the contrast performance of the light-emitting device 1.

[0040] The upper surface 11 is theoretically divided into surface areas 11a, 11b, ..., each one of which is assigned to an individual portion 2a, 2b, ... of the semiconductor layer stack 2. The theoretical division is made along a dividing line / plane 18 that passes through the semiconductor layer stack 2 between two adjacent pixels. The individual roughened interface areas 12a, 12b, ... are respectively located within the theoretically divided surface areas 11a, 11b, ..., away from the periphery 13a, 13b, ... of the respective surface areas 11a, 11b, ....

[0041] As shown in FIG. 4 , the individual roughened interface areas 12 a, 12 b, ... are further away from the adjacent edge of an adjacent surface area (distance D2) than from the opposing edge of the respective surface area (distance D1). In particular, the individual roughened interface areas 12 a, 12 b, ... are further away from the “inner” edge of the surface area (distance D2) than from the “outer” edge of the surface area (distance D1), with the “outer” edge of the surface area being closer to the side surface 16 of the semiconductor stack 2 than the “inner” edge. As a result, pixel illumination of the light-emitting device is more uniform across the “inner” pixels as well as the “edge” pixels. In FIG. 4 , this is indicated by distances D1 and D2, where D1 is the distance from the outer edge of the light-emitting device to the roughened interface of one of the pixels, and D2 is the distance from the inner edge or dividing line / face 18 to the roughened interface of the pixel.

[0042] However, the embodiments shown in Figures 2 and 3 are understood to be exemplary embodiments only and can be extended to the left or right to form an array of pixels arranged side by side, with a common converter layer disposed on top of the pixels, similar to the embodiment shown in Figure 4.

[0043] 5A and 5B each show a top view of an embodiment of a light emitting device according to some aspects of the proposed principles, and in particular show a light emitting device including several pixels arranged next to each other in a cloverleaf design.

[0044] 5A shows an embodiment in which each individual portion 2a, 2b,... of the semiconductor stack 2 is assigned its own contact via 7a, 7b,... along two edges of the individual portion 2a, 2b,... In the illustrated embodiment, the individual portions 2a, 2b,... are divided in a cross shape by reflective sidewalls 15, which extend throughout the entire semiconductor stack 2 and completely separate the first layer, the second layer, and the active region from one another. The top surface 11 of the semiconductor stack 2 is theoretically divided into surface areas 11a, 11b,... along dividing lines / planes 18, and the individual roughened interface areas 12a, 12b,... are located within the theoretically divided surface areas 11a, 11b,... respectively, away from the outer peripheries 13a, 13b,... of the respective surface areas 11a, 11b,...

[0045] 5B shows an embodiment in which the individual portions 2a, 2b, ... of the semiconductor stack 2 are electrically connected through a common electrical contact by contact vias 7 that extend crosswise through the first layer, the active region, and part of the second layer. The top surface 11 of the semiconductor stack 2 is theoretically divided into surface areas 11a, 11b, ... along dividing lines / planes 18, and the individual roughened interface areas 12a, 12b, ... are respectively located within the theoretically divided surface areas 11a, 11b, ... away from the peripheries 13a, 13b, ... of the respective surface areas 11a, 11b, ... [Explanation of symbols]

[0046] 1 Light-emitting devices 2. Semiconductor laminate 2a, 2b, … individual parts 3. First Layer 4 Second Layer 5 Active area 5a,5b,... active region 6 First Electrical Contact 7 Contact Vias 7a, 7b, ... Contact vias 8 Second Electrical Contact 8a, 8b, ... second electrical contacts 9 Bottom 10 Transformation Layer 11 Top side 11a, 11b, ... surface area 12 Roughened interface 12a, 12b, … roughened interface area 13 Outer perimeter 13a, 13b outer circumference 14 Coating 15 Reflective sidewall 16 Side 17 Reflective layer 18 Dividing Line L1 Light with the first wavelength L1: Light ray with second wavelength D1 Distance D2 distance

Claims

1. a semiconductor layer stack (2) having a first layer (3) of a first doping type, a second layer (4) of a second doping type, and an active region (5) arranged between the first and second layers; a first electrical contact (6) connected to an electrical contact via (7), said electrical contact via extending electrically isolated through said second layer (4) and said active area (5) and contacting said first layer (3); a second electrical contact (8) contacting the second layer (4), the first electrical contact (6) and the second electrical contact (8) being arranged on the second layer (4) on the bottom surface (9) of the semiconductor layer stack (2); Equipped with the interface (12) between the top surface (11) of the semiconductor layer sequence (2) and the medium above the top surface (11) is roughened in an area smaller than the area of ​​the top surface (11), in particular in an area at least 10% smaller than the area of ​​the top surface (11); Light-emitting device (1).

2. the medium above the top surface (11) is a converter layer (10) arranged on the first layer (3) of the top surface (11) of the semiconductor layer stack (2), the converter layer (10) being configured to convert light of a first wavelength (L1) generated in the active region (5) into light of a second wavelength (L2); The light emitting device of claim 1 .

3. The roughened interface (12) is spaced from the outer periphery (13) of the upper surface (11).

3. A light-emitting device according to claim 1 or 2.

4. the interface (12) between the first layer (3) and the converter layer (10) is roughened in a central area above the active region (5), the central area being at least 10% smaller than the protrusion of the active region when viewed in a direction perpendicular to the top surface (11); 4. A light-emitting device according to claim 2 or 3.

5. The roughened interface (12) provides better extraction of light from the top surface (11) into the converter layer (10) compared to a non-roughened interface. A light-emitting device according to any one of claims 1 to 4.

6. a coating (14) disposed on the top surface (11) surrounding the roughened interface (12), the coating (14) comprising a higher transmittance for light incident on the coating perpendicular to the top surface (11) than for light incident on the coating at a shallower angle relative to the top surface (11); A light-emitting device according to any one of claims 1 to 5.

7. A reflective sidewall (15) is arranged on at least one side surface (16) of the semiconductor stack (2), the side surface (16) connecting the top surface (11) and the bottom surface (9) to each other. A light-emitting device according to any one of claims 1 to 6.

8. a reflective layer (17) is arranged on the bottom surface (9) of the semiconductor layer stack (2), the reflective layer (17) surrounding the first electrical contact (6) and the second electrical contact (8); A light-emitting device according to any one of claims 1 to 7.

9. At least the second layer (4) and the active region (5) are separated into a first portion and at least a second portion (2a, 2b, ...), A light-emitting device according to any one of claims 1 to 8.

10. the first portion and the at least second portion (2a, 2b, ...) are separated by the electrical contact via (7); 10. The light emitting device of claim 9.

11. above each of the first and at least second portions (2a, 2b, ...), the interface (12) between the first layer (3) and the converter layer (10) is roughened in distinct areas (12a, 12b, ...), the distinct areas (12a, 12b, ...) being spaced apart from one another; 11. A light-emitting device according to claim 9 or 10.

12. the upper surface (11) is theoretically divided into surface areas (11a, 11b, ...), one surface area each being assigned to the first portion and the at least second portion (2a, 2b, ...), and the individual roughened interface areas (12a, 12b, ...) are respectively spaced apart from the outer periphery (13a, 13b, ...) of each of the surface areas (11a, 11b, ...); 12. The light emitting device of claim 11.

13. the individual roughened interface areas (12a, 12b, ...) are further apart from adjacent edges of adjacent surface areas (11a, 11b, ...) than from opposite edges of the respective surface areas (11a, 11b, ...); 13. The light emitting device of claim 12.

14. each of the second electrical contacts (8a, 8b, ...) contacts a respective portion of the second layer (4) of the first portion and the at least second portion (2a, 2b, ...); A light-emitting device according to any one of claims 9 to 13.

15. The light emitting device (1) comprises at least one micro LED, A light-emitting device according to any one of claims 1 to 14.

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