InGaAlP-based fast switching micro LED for high-speed data communication

Abstract

The present invention relates to a micro LED comprising a semiconductor layer stack having a first charge transport layer of a first doping type, a second charge transport layer of a second doping type, and an active region arranged between the first charge transport layer and the second charge transport layer. The semiconductor layer stack includes a top surface and a side surface adjacent to the top surface, where the side surface is inclined with respect to a normal to the top surface. The semiconductor layer stack is also based on an aluminum gallium indium phosphide system. Additionally, the micro LED includes: a regrowth layer covering the side surface; and a first contact element disposed on the first charge transport layer and a second contact element in electrical contact with the second charge transport layer. Thus, an edge region of the active region adjacent to the side surface is contaminated with at least one of: oxygen; iron; silicon; magnesium; sulfur; tellurium; beryllium; and boron.

Description

[0001] This application claims the priority of German patent application DE 10 2023 101 569.9, filed on January 23, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a micro-LED (μ-LED) used as a means for optical data communication, and a method for manufacturing the micro-LED. Background Art

[0003] Today's internet relies on massive data centers. However, the high power consumption of these large data centers poses a challenge in ensuring they operate using purely sustainable energy. Much of this power consumption isn't used for computation, but for transferring data over short distances (<<10m): from CPU to GPU, server to server, and rack to rack.

[0004] Currently, short-range data communication is mainly carried out electrically through copper (Cu) or aluminum (Al) feeders and wires (inside the chip or on the motherboard), or optically through a combination of near-infrared (NIR) vertical cavity surface emitting lasers (VCSELs) and optical fibers. However, metals cause electrical power losses due to their specific resistance, and on the other hand, VCSELs require a certain threshold current (I th ) to start laser emission, the threshold current is usually in the mA range. Together with the necessary forward voltage, the threshold current I th The dissipated (electrical) power is limited to a few mW.

[0005] In order to reduce the power of optical short-range data transmission, there is an activity to use blue indium gallium nitride (InGaN) microLEDs to meet the challenge of high power consumption. That is, InGaN microLEDs have the advantage of being able to operate at low currents (1μA to 500μA per pixel), which is many times lower than the operating current of lasers (such as VCSELs), and InGaN microLEDs do not need to pass a (laser) threshold. Additionally, InGaN microLEDs have a small footprint (possibly <5μm) and can be transferred to backplane wafers using common display technologies, so high parallelization can be achieved when transferring the microLEDs, thereby further reducing power consumption when manufacturing the hardware.

[0006] On the other hand, however, InGaN microLEDs are disadvantageous for data transmission via multi-core optical fibers, because the blue light emitted by the InGaN microLEDs is increasingly absorbed as the length of the optical fiber increases, and silicon (Si)-based detectors may only provide poor sensitivity to blue light. Therefore, optical data transmission using InGaN microLEDs is limited to "very short" distances. When increasing the amount of indium in the InGaN, the light emitted by the InGaN microLEDs can be shifted to longer wavelengths (e.g., green), which will reduce the absorption within the optical fiber, and the Si-based detectors will include a higher sensitivity to light with longer wavelengths (e.g., green). However, increasing the indium in the InGaN is accompanied by a reduced switching speed of the InGaN-based microLEDs due to the increased piezoelectric field (strain) within the microLED.

[0007] It is therefore an object of the present invention to provide an optoelectronic component which can be used for optical data communication with reduced energy consumption while maintaining or even increasing the data transmission rate to be achieved or the switching time required therefor. Summary of the Invention

[0008] This and other objects are solved by the subject matter of the independent claims. Characteristics and further aspects of the proposed principle are outlined in the dependent claims.

[0009] According to one aspect of the present invention, a micro-LED is provided. The micro-LED comprises a semiconductor layer stack having a first charge transport layer of a first doping type, a second charge transport layer of a second doping type, and an active region disposed between the first and second charge transport layers. The semiconductor layer stack further comprises a top surface and side surfaces adjacent to the top surface, wherein the side surfaces are tilted relative to a normal to the top surface. This tilting can in particular be the result of a first etching step of the epitaxial structure on the wafer to separate the individual islands of active region, which then subsequently become each part of an optoelectronic device.

[0010] Furthermore, the semiconductor layer stack is based on an aluminum gallium indium phosphide (InGaAlP) system. Additionally, the micro-LED includes: a regrown layer covering the side surface; a first contact element disposed on the first charge transport layer; and a second contact element in electrical contact with the second charge transport layer. Edge regions of the active area adjacent to the side surface are contaminated with at least one of the following: oxygen; iron; silicon; magnesium; sulfur; tellurium; beryllium; and boron.

[0011] The concept of the present invention is based on the use of InGaAlP microLEDs instead of InGaN. Initially, the InGaAlP material system was not well suited for high-speed data communication applications because, when miniaturized to smaller LED sizes (microLEDs), InGaAlP LEDs are typically characterized by slow switching speeds due to high charge carrier lifetime / diffusion length and low quantum efficiency (internal and external). However, the miniaturization of microLEDs and, therefore, the reduction in their size has the effect that the charge carrier diffusion length / mean free path and, therefore, the charge carrier lifetime are simultaneously reduced, leading to faster turn-off times and, therefore, potentially faster switching speeds of the microLEDs.

[0012] At the same time, the inefficient quantum efficiency can be addressed by the use of regrowth and / or quantum well intermixing (QWI) to improve the radiative recombination efficiency. Controlled regrowth and, therefore, controlled regulation / tuning of defects at the regrowth interface can then in turn be used to optimize the switching speed, since controlled (fast) non-radiative recombination (NRR) processes near the active region allow for a further reduction in the turn-off time of the micro-LED and, therefore, potentially faster switching speeds. The idea of ​​the present invention is therefore to find a good balance for the emissive brightness of the micro-LED while still being able to provide the desired switching speed for the respective target application.

[0013] Compared with InGaN micro LEDs, the present invention may have the following advantages:

[0014] Due to the different crystal structure, there is no piezoelectric field in the semiconductor which could separate the charge carriers and thus reduce the switching speed.

[0015] - Silicon-based detectors include higher sensitivity at yellow / red emission spectra (InGaAlP) compared to blue wavelengths (InGaN).

[0016] - Reduced absorption of light in the yellow / red emission spectrum (InGaAlP) compared to blue wavelengths (InGaN) in optical fibers (plastic (multi-core) fibers).

[0017] The term "charge carrier lifetime" is to be understood as meaning, in particular, the time t until charge carriers in the active region recombine under optical or non-radiative emission. A high charge carrier lifetime is associated with a high off-time of the microLED and, therefore, a reduced possible switching time, since charge carriers with a higher lifetime in the active region can recombine under optical emission after the microLED has been disconnected from its power supply. This "afterglow" does not allow for fast switching frequencies, for example in the GHz range.

[0018] Increasing the probability of recombination under light emission or non-radiative recombination reduces charge carrier lifetime and simultaneously increases the probability of providing fast switching frequencies. To increase the probability of non-radiative recombination, the edge region of the active region adjacent to the side surface is contaminated with at least one of the following: oxygen; iron; silicon; magnesium; sulfur; tellurium; beryllium; and boron.

[0019] This can be achieved by, on the one hand, controlling the mesa etching of the semiconductor layer stack to provide inclined side surfaces and, on the other hand, controlling the regrowth process to cover the etched side surfaces with the regrown layer. Thus, the number of defects (dangling bonds / non-radiative recombination centers) along the side surfaces, and in particular in the edge regions of the active region, can be controlled, again influencing the probability of non-radiative recombination in the active region. In particular, the diffusion length / mean free path of the charge carriers is thereby confined to the central region of the active region between the edge regions, where recombination of the charge carriers under photoemission can occur, resulting in a reduced charge carrier lifetime.

[0020] According to some aspects, when viewed on the top surface, a central region of the first charge transport layer below the active area remains free of the first contact element. The first contact element may, for example, comprise a ring-shaped form. This allows for an uneven distribution of current through the active area, since the current will seek the path with the least total resistance, which in most cases is associated with the shortest path, and the current propagates along the side surfaces rather than around the center of the active area. By optimizing the contact design, the current flow near the regrown area / side surface can thus be facilitated. Additionally, this can be used to provide a light emission window without the first contact element, through which light is emitted from the micro-LED.

[0021] The regrown layer covering the side surface can be, for example, undoped or include multiple sublayers of different doping types arranged in an alternating order. For example, the first regrown layer can include multiple n-doped and p-doped sublayers forming an npnp-barrier layer in an alternating order.

[0022] In this case, the regrown layer may cover the side surfaces but may leave at least part of the top surface exposed. However, the regrown layer may also form the top contact of the micro-LED. In this case, the regrown layer may, for example, be of the second doping type and cover the side surfaces as well as the top surface. The regrown layer may, for example, be obtained by regrowing in combination with a selective area growth (SAG) mask placed on top of the individual islands of active area separated by the first etching step of the epitaxial structure on the wafer.

[0023] This is then followed by the growth of a regrown layer. The regrown layer can in particular be an undoped or npnp current blocking layer of high bandgap, such as indium aluminum phosphide (InAlP), grown on the island sidewalls and also in the areas between the islands. However, the regrown layer can also be obtained by regrowth after the SAG mask of the first etching step has been removed and can include a highly conductive contact layer, such as gallium phosphide (GaP) or gallium arsenide (GaAs).

[0024] According to at least one aspect, microLEDs are very small LEDs with an edge length of less than 20 μm, less than 10 μm, or even less than 5 μm. At such small sizes, the already small lateral extension of the active area can have a positive effect on the present invention with respect to the diffusion length / mean free path.

[0025] According to at least one aspect, the substantially uncontaminated central region of the active region between the edge regions includes a lateral dimension between the edge regions that is smaller than a diffusion length of the material system of the active region. This further reduces charge carrier lifetime and enables desired micro-LED switching times to be achieved.

[0026] According to at least one aspect, the microLED is configured to have a turn-off time in the range of 0.5 ns to 10 ns, in particular a turn-off time as low as 0.1 ns. With such turn-off times, fast switching frequencies, for example in the GHz range, can be achieved.

[0027] According to at least one aspect, the density of contamination in the edge region is 10 16 per cm 3 with 10 20 per cm 3 between 10 17 per cm 3 with 10 19 With such a contamination density, a desired “number” of NRR centers can be set in the edge region to reduce the charge carrier lifetime to a desired level.

[0028] According to at least one aspect, the edge region additionally comprises dislocation defects, in particular stacking faults and / or threading dislocations and / or alloy fluctuations. Such dislocation defects can act like contamination of NRR centers, thereby reducing the charge carrier lifetime in the active region.

[0029] According to at least one aspect, the micro-LED further comprises a passivation layer disposed on the exposed surface of the regrown layer and / or layer stack. In particular, the mesa edges resulting from singulating the micro-LEDs during the second etching step can be passivated by means of the passivation layer. This reduces / prevents any potential undesirable interference along these mesa edges.

[0030] According to a further aspect of the present invention, the micro-LED according to at least one of the aforementioned aspects can be used as a means for optical data communication, in particular short-range communication of less than 10 m. The micro-LED according to at least one of the aforementioned aspects can be particularly used for data transmission in large data centers, etc., to transmit data over short distances (<<10 m), for example from CPU to GPU, server to server, and / or rack to rack.

[0031] According to another aspect of the present invention, a microLED can be used as a means for optical data communication, in particular for short-distance communication of less than 10 m. The microLED comprises a semiconductor layer stack having a first charge transport layer of a first doping type, a second charge transport layer of a second doping type, and an active region arranged between the first and second charge transport layers. The semiconductor layer stack further comprises a top surface and side surfaces adjacent to the top surface, wherein the side surfaces are inclined relative to the normal to the top surface. This inclination can in particular be the result of a first etching step of the epitaxial structure on the wafer to separate the individual islands of active region, which are then each part of an optoelectronic device.

[0032] Furthermore, the semiconductor layer stack is based on an aluminum gallium indium phosphide (InGaAlP) system. Additionally, the micro LED includes: a regrown layer covering the side surface; and a first contact element arranged on the first charge transport layer and a second contact element electrically contacting the second charge transport layer.

[0033] According to another aspect of the present invention, there is provided a method for manufacturing a micro-LED, the method comprising the following steps:

[0034] Providing a semiconductor layer stack having a first charge transport layer of a first doping type, a second charge transport layer of a second doping type, and an active region arranged between the first charge transport layer and the second charge transport layer;

[0035] providing a structured mask on a top surface of the semiconductor layer stack;

[0036] structuring the semiconductor layer stack such that the semiconductor layer stack comprises a side surface adjacent to the top surface, wherein the side surface is inclined relative to a normal to the top surface;

[0037] regrowing a regrown layer on the side surface;

[0038] providing a first contact element on the first charge transport layer; and

[0039] a second contact element provided in electrical contact with the second charge transport layer;

[0040] The step of structuring the semiconductor layer stack comprises contaminating an edge region of the active region adjacent to the side surface by at least one of the following:

[0041] oxygen;

[0042] iron;

[0043] silicon;

[0044] magnesium;

[0045] sulfur;

[0046] tellurium;

[0047] Beryllium; and

[0048] boron.

[0049] Thus, the degree of contamination can be adjusted in particular by means of at least one of the following parameters:

[0050] - the angle of the side surface relative to the normal to the top surface;

[0051] - physical / chemical pretreatment of the layer stack and / or the side surfaces; and

[0052] - Epitaxial conditions of the layer stack.

[0053] According to at least one aspect, the step of structuring the semiconductor layer stack comprises contaminating the edge region with dislocation defects, in particular stacking faults and / or threading dislocations and / or alloy fluctuations.

[0054] According to at least one aspect, the contamination step is performed / adjusted such that a substantially uncontaminated central region of the active region between the edge regions comprises a lateral dimension between the edge regions that is smaller than a diffusion length of a material system of the active region.

[0055] According to at least one aspect, providing the first contact element includes leaving a central region of the first charge transport layer below the active region free of the first contact element when viewed on the top surface.

[0056] According to at least one aspect, the method further comprises the step of providing a passivation layer on the exposed surface of the regrown layer and / or on the exposed surface of the layer stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Further aspects and embodiments according to the proposed principles will become apparent with respect to the various embodiments and examples described in detail with reference to the accompanying drawings, in which:

[0058] Figures 1 to 3 The steps of a method for manufacturing a micro-LED according to some aspects of the present invention are shown; and

[0059] Figure 4 and Figure 5 Each shows a cross section of a micro-LED according to aspects of the present invention. DETAILED DESCRIPTION

[0060] The following embodiments and examples disclose various aspects and combinations thereof according to the principles set forth. The embodiments and examples are not always drawn to scale. Similarly, different elements may be shown enlarged or reduced in size to emphasize various aspects. It goes without saying that the various aspects of the embodiments and examples shown in the accompanying drawings can be combined with one another without contradicting the principles of the present invention. Some aspects illustrate regular structures or forms. It should be noted that in practice, slight differences and deviations from the ideal form may occur, but these do not contradict the inventive concept.

[0061] Additionally, the various figures and aspects are not necessarily shown to exact scale, nor are the proportions between the various elements necessarily substantially correct. Some aspects are highlighted by enlarging them. However, terms such as "above," "upper," "below," "lower," "larger," "smaller," etc., are intended to accurately represent the elements in the figures. Therefore, such relationships between the elements can be inferred based on the figures.

[0062] Figures 1 to 3 Steps of a method for fabricating a micro-LED according to aspects of the present invention are shown.

[0063] In the first step, as Figure 1 As shown in , a layer stack 2 comprising a first charge transport layer 3, an active region 5 and a second charge transport layer 4 is grown on a carrier substrate 11. As shown, the first charge transport layer 3 and the second charge transport layer 4 can each include several sublayers to provide a layer stack 2 together with the active region 5, which is configured to emit light of a desired wavelength when supplied with sufficient current. The first charge transport layer 3 can, for example, include one or several n-doped layers and one or several diffusion barrier layers adjacent to the active region 5. On the other hand, the second charge transport layer 4 can, for example, include one or several p-doped layers and one or several diffusion barrier layers adjacent to the active region 5. The diffusion barrier layer can in particular be configured to prevent n-dopants or p-dopants of the n-doped layer or the p-doped layer from diffusing into the active region 5.

[0064] The layer stack 2 is then structured as Figure 2As shown in , the layer stack 2 is structured by, for example, providing a structured mask (not shown) on the top surface 2a of the layer stack 2 and then by means of, for example, a first mesa etching process. Due to this structuring, the individual islands of the active area 5 of the layer stack are separated so that each of the individual islands of the active area 5 is bounded by an inclined side surface 2b. By way of example, in Figure 2 and Figure 3 In the figure, only one resulting individual island of the active area 5 is shown, but by means of "..." it will be understood that a plurality of such individual islands can be arranged adjacent to one another on the carrier substrate 11. The layer stack 2 shown comprises a top surface 2a and a side surface 2b adjacent to the top surface, wherein the side surface is inclined relative to a normal N of the top surface 2a. The side surface 2b can be inclined, for example, at an angle α of 0° to 45° relative to the surface normal, and in particular at an angle of 5° to 15°.

[0065] Then, if Figure 3 As shown in FIG, on the layer stack 2 and in particular on the side surface 2b, a regrown layer 6 is grown, in particular epitaxially, in order to encapsulate the side surface 2b and / or to provide a contact layer on the top surface 2a. In the embodiment shown, the regrown layer 6 includes several sublayers, in particular layers of the second doping type, in order to provide contact layers for the subsequent micro-LEDs.

[0066] With the help of controlled etching and subsequent regrowth steps, e.g. Figure 2 and Figure 3 As shown in , a controlled regulation / adjustment of defects at the regrown interface can be achieved to optimize the switching speed of the microLED. Thus, at least the edge region 9 of the active area 5 adjacent to the side surface 2b is contaminated in a controlled manner with at least one of the following: oxygen; iron; silicon; magnesium; sulfur; tellurium; beryllium; and boron. The contamination of the edge region produces NRR centers, the number of which can be adjusted by means of a controllable process. When operating the microLED, a controlled (fast) non-radiative recombination (NRR) process near the active area 5 is therefore achievable and allows a reduction in the turn-off time of the microLED, and thus faster switching speeds are possible. Therefore, the idea of ​​the present invention is to find a good balance for the emissive brightness of the microLED while still being able to provide the desired switching speed for the corresponding target application.

[0067] Due to the second mesa etching process (not shown), the microLED as a whole is also structured to optically and electrically isolate several microLEDs, while in contrast to the first mesa etching process the resulting side surfaces / mesa edges do not include parts of the active area 5 .

[0068] Figure 4 and Figure 5Each shows a cross section of a micro-LED 1 according to some aspects of the present invention. The micro-LED 1 each comprises a layer stack 2, in particular a semiconductor layer stack, having a first charge transport layer 3 of a first doping type, a second charge transport layer 4 of a second doping type, and an active region 5 arranged between the first and second charge transport layers. However, as Figures 1 to 3 As shown in the manufacturing steps in FIG, the carrier substrate 11 and a portion of the first charge transport layer 3 are Figures 1 to 3 Compared to has been removed.

[0069] The layer stack 2 comprises a top surface 2a and a side surface 2b adjacent to the top surface, wherein the side surface 2b is inclined relative to a normal N to the top surface 2a. This inclination can in particular be Figure 2 The result of the first etching step is shown in . The optoelectronic device 1 further comprises a regrown layer 6 covering the side surfaces 2 b and the top surface 2 a and forming a contact layer for the micro-LED 1. Additionally, a first contact element 7 a is arranged on the first charge transport layer 3, and a second contact element 7 b, which is in electrical contact with the second charge transport layer 4, is arranged on the regrown layer 6. To provide electrical contact, the regrown layer 6 is an at least partially electrically conductive layer and, in particular, a semiconductor layer of the second doping type or an arrangement of several semiconductor layers of the second doping type.

[0070] The first contact element 7a is formed such that, when viewed on the top surface 2a, a central region of the first charge transport layer 3 below the active area 5 remains free of the first contact element 7a. This can be particularly true for first contact elements 7a having a ring-shaped form arranged on the first charge transport layer 3. This allows for an uneven distribution of the current through the active area 5, since the current will seek the path of least overall resistance, which in most cases is associated with the shortest path, and the current will propagate through the edge region 9 along the side surface 2b instead of bypassing the center 10 of the active area 5.

[0071] Apart from Figure 4 In addition to the embodiments shown in Figure 5 The micro-LED 1 shown in FIG further comprises a passivation layer 8, which is arranged on the exposed surface of the regrown layer 6 and the exposed side surfaces of the layer stack 2 (obtained by the second etching step of singulating the micro-LEDs). In particular, the mesa edges obtained by the second etching step of singulating the micro-LEDs can be passivated by means of the passivation layer 8. In this way, possible undesirable interference along these mesa edges can be reduced / prevented.

[0072] Reference Signs List

[0073] 1 Micro LED

[0074] 2-layer stacking

[0075] 2a Top surface

[0076] 2b Side surface

[0077] 3 Charge transport layer

[0078] 4 Charge transport layer

[0079] 5 Active area

[0080] 6 Regrowth layer

[0081] 7a, 7b contact elements

[0082] 8 Passivation layer

[0083] 9 Marginal Area

[0084] 10 Central Area

[0085] 11 Carrier substrate

[0086] N Surface Normal

[0087] α angle.

Claims

1. A micro LED (1), comprising: A semiconductor layer stack (2), comprising a first charge transport layer (3) of a first doping type, a second charge transport layer (4) of a second doping type, and an active region (5) arranged between the first charge transport layer (3) and the second charge transport layer (4), wherein the semiconductor layer stack (2) comprises a top surface (2a) and a side surface (2b) adjacent to the top surface (2a), wherein the side surface (2b) is inclined relative to a normal (N) to the top surface (2a), and wherein the semiconductor layer stack (2) is based on an aluminum gallium indium phosphide system; a regrown layer (6) covering the side surface (2b); and a first contact element (7a) arranged on the first charge transport layer (3) and a second contact element (7b) in electrical contact with the second charge transport layer (4); The edge region (9) of the active region (5) adjacent to the side surface (2b) is contaminated by at least one of the following: oxygen; iron; silicon; magnesium; sulfur; tellurium; Beryllium; and boron.

2. The micro LED according to claim 1, wherein: When viewed on the top surface (2a), a central region of the first charge transport layer (3) below the active area (5) remains free of the first contact element (7a).

3. The micro-LED according to claim 2, wherein: The first contact element (2a) comprises an annular form.

4. The micro-LED according to claim 1 , wherein: The substantially uncontaminated central region (10) of the active region (5) between the edge regions (9) comprises a lateral dimension between the edge regions (9) which is smaller than a diffusion length of the material system of the active region (5).

5. The micro-LED according to any one of the preceding claims, wherein The micro LED (1) is configured to have a turn-off time in the range of 0,1 ns to 10 ns.

6. The micro-LED according to any one of the preceding claims, wherein The density of contamination in the edge region (9) is 10 16 per cm 3 with 10 20 per cm 3 between.

7. The micro-LED according to any one of the preceding claims, wherein The edge region (9) additionally comprises dislocation defects, in particular stacking faults and / or threading dislocations and / or alloy fluctuations.

8. The micro-LED according to any of the preceding claims, further comprising a passivation layer (8) arranged on the exposed surface of the regrown layer (6) and / or on the exposed surface of the layer stack (2).

9. Use of a micro-LED (1) according to any of the preceding claims as a means for optical data communication, in particular short-range communication of less than 10 m.

10. A micro-LED (1) is used as a means for optical data communication, in particular short-distance communication less than 10 m, the micro-LED (1) comprising: A semiconductor layer stack (2), comprising a first charge transport layer (3) of a first doping type, a second charge transport layer (4) of a second doping type, and an active region (5) arranged between the first charge transport layer (3) and the second charge transport layer (4), wherein the semiconductor layer stack (2) comprises a top surface (2a) and a side surface (2b) adjacent to the top surface (2a), wherein the side surface (2b) is inclined relative to a normal (N) to the top surface (2a), and wherein the semiconductor layer stack (2) is based on an aluminum gallium indium phosphide system; a regrown layer (6) covering the side surface (2b); and A first contact element (7a) is arranged on the first charge transport layer (3) and a second contact element (7b) is in electrical contact with the second charge transport layer (4).

11. A method for manufacturing a micro LED (1), comprising the following steps: A semiconductor layer stack (2) is provided, wherein the semiconductor layer stack (2) comprises a first charge transport layer (3) of a first doping type, a second charge transport layer (4) of a second doping type, and an active region (5) arranged between the first charge transport layer (3) and the second charge transport layer (4); providing a structured mask on the top surface (2a) of the semiconductor layer stack (2); Structuring the semiconductor layer stack (2) such that the semiconductor layer stack (2) comprises a side surface (2b) adjacent to the top surface (2a), wherein the side surface (2b) is inclined relative to a normal (N) to the top surface (2a); regrowing a regrowth layer (6) on the side surface (2b); providing a first contact element (7a) on the first charge transport layer (3); and A second contact element (7b) is provided in electrical contact with the second charge transport layer (4); The step of structuring the semiconductor layer stack (2) comprises contaminating an edge region (9) of the active region (5) adjacent to the side surface (2b) by at least one of: oxygen; iron; silicon; magnesium; sulfur; tellurium; Beryllium; and boron.

12. The method according to claim 11, wherein The step of structuring the semiconductor layer stack (2) comprises contaminating the edge region (9) with dislocation defects, in particular stacking faults and / or threading dislocations and / or alloy fluctuations.

13. The method according to claim 11 or 12, wherein: The contamination step is performed so that a substantially uncontaminated central region (10) of the active region (5) between the edge regions (9) comprises a lateral dimension between the edge regions (9) that is smaller than a diffusion length of the material system of the active region (5).

14. The method according to any one of claims 11 to 13, wherein The step of providing the first contact element (7a) includes leaving a central area of ​​the first charge transport layer (3) below the active area (5) free of the first contact element (7a) when viewed on the top surface (2a).

15. The method according to any one of claims 11 to 14, further comprising the steps of: A passivation layer (8) is provided on the exposed surface of the regrown layer (6) and / or the exposed surface of the layer stack (2).

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