Surface-emitting semiconductor laser and method for manufacturing a surface-emitting semiconductor laser

Abstract

Laser device (25) with an arrangement of a plurality of surface-emitting semiconductor laser elements (1481, 1482, 1483), wherein each of the semiconductor laser elements (148) comprises the following: a first semiconductor layer (110) of a first conductivity type; and an active zone (115) suitable for generating electromagnetic radiation (20); wherein the arrangement further an ordered photonic structure (132); a second semiconductor layer (120) of a second conductivity type, comprising a first and a second contact element (112, 122), wherein the ordered photonic structure (132) and the second semiconductor layer (122) are associated with at least two semiconductor laser elements (1481, 1482), wherein a horizontal dimension of the semiconductor laser elements (148, 1481, 1482, 1483) is each less than 10 µm and a horizontal dimension of the ordered photonic structure (132) is greater than 10 µm, the second contact element (122) is electrically connected to the second semiconductor layer (120), wherein the active zone (115) is arranged between the first semiconductor layer (110) and the second semiconductor layer (120), the ordered photonic structure (132) is arranged between the active zone (115) and the second contact element (122).

Description

[0001] Surface-emitting lasers, i.e., laser devices in which the generated laser light is emitted perpendicular to a surface of a semiconductor layer arrangement, can be used in a variety of applications, for example in AR ("Augmented Reality") applications or in 3D sensor systems, for example for face recognition or distance measurement in autonomous driving, or for general lighting purposes, for example for display devices.

[0002] Other surface-emitting semiconductor lasers are known, for example, from publications US 2007 / 0201527A1, US 2019 / 0319428A1, JP 2010-93127A, WO2010 / 087231A1 and US 2011 / 0076791A1.

[0003] Generally, efforts are being made to improve such surface-emitting lasers.

[0004] The present invention is based on the objective of providing an improved surface-emitting semiconductor laser and an improved method for manufacturing a surface-emitting semiconductor laser.

[0005] According to the present invention, the problem is solved by the subject matter and the method of the independent patent claims.

[0006] According to embodiments, a laser device comprises an arrangement of a plurality of surface-emitting semiconductor laser elements. Each of the semiconductor laser elements comprises a first semiconductor layer of a first conductivity type and an active zone capable of generating electromagnetic radiation. The arrangement further comprises an ordered photonic structure, a second semiconductor layer of a second conductivity type, and a first and a second contact element. The ordered photonic structure and the second semiconductor layer are associated with at least two semiconductor laser elements. The second contact element is electrically connected to the second semiconductor layer. The active zone is arranged between the first semiconductor layer and the second semiconductor layer. The ordered photonic structure is arranged between the active zone and the second contact element.

[0007] Each horizontal dimension of the semiconductor laser elements is less than 10 µm. Each horizontal dimension of the ordered photonic structure is greater than 10 µm.

[0008] For example, the active zones of the individual semiconductor laser elements are electrically isolated from each other, and a filler material is arranged in a space between adjacent semiconductor laser elements.

[0009] According to embodiments, the second semiconductor layer borders the second contact element, and the ordered photonic structure is arranged in the second semiconductor layer.

[0010] For example, the laser device can further comprise a third semiconductor layer of the first conductivity type adjacent to the second contact element, as well as a tunnel junction suitable for electrically connecting the second semiconductor layer to the third semiconductor layer, wherein the ordered photonic structure is arranged in the third semiconductor layer.

[0011] The accompanying drawings serve to illustrate exemplary embodiments of the invention. The drawings depict these embodiments and, together with the description, explain them. Further exemplary embodiments and many of the intended advantages will become apparent from the detailed description below. The elements and structures shown in the drawings are not necessarily drawn to scale. Identical reference numerals refer to identical or corresponding elements and structures. Fig. Figure 1 shows a general structure of a surface-emitting semiconductor laser with an ordered photonic structure. Fig. Figure 2 shows a schematic cross-sectional view of a surface-emitting semiconductor laser according to examples. The Fig. Figures 3A to 3I illustrate cross-sectional views of a workpiece when performing a procedure according to examples. Fig. Figure 4 shows a schematic cross-sectional view of a surface-emitting semiconductor laser according to further examples. The Fig. Figures 5A to 5F illustrate cross-sectional views of a workpiece when performing a procedure according to further examples. The Fig. Figures 6A to 6C illustrate cross-sectional views of a workpiece during further processing according to examples. Fig. 6D and Fig. Figure 6E shows cross-sectional views of a workpiece to illustrate process variants. Fig. Section 7 summarizes a procedure using examples. Fig. Figure 8A shows a top view of a surface-emitting semiconductor laser according to examples. Fig. Figure 8B shows a cross-sectional view of a surface-emitting semiconductor laser according to examples. Fig. Figure 8C shows an intensity distribution of a laser device according to examples. Fig. 8D illustrates a laser device according to examples. Fig. Figure 9A shows a cross-sectional view of a laser device according to embodiments. Fig. Figure 9B shows a top view of a laser device according to embodiments. Fig. Figure 9C shows a cross-sectional view of a laser device according to further embodiments. Fig. Figure 10A shows a schematic view of a lighting device according to embodiments. Fig. Figure 10B illustrates an application of a lighting device according to embodiments. Fig. Figure 11A shows a cross-sectional view of a laser device according to embodiments. Fig. Figure 11B shows a schematic cross-sectional view of a laser device according to further embodiments. Fig. Figure 11C shows a schematic cross-sectional view of a laser device according to further examples. Fig. Figure 11D shows a schematic cross-sectional view of a laser device according to further examples.

[0012] The following detailed description refers to the accompanying drawings, which form part of the disclosure and show specific embodiments for illustrative purposes. In this context, directional terminology such as "top," "bottom," "front," "back," "over," "on," "in front," "behind," "front," "back," etc., refers to the orientation of the figures just described. Since the components of the embodiments can be positioned in different orientations, the directional terminology serves only for explanation and is in no way restrictive.

[0013] The description of the embodiments is not limiting, as other embodiments exist and structural or logical modifications can be made without deviating from the scope defined by the claims. In particular, elements of the embodiments described below can be combined with elements of other described embodiments, unless the context indicates otherwise.

[0014] The terms "wafer" or "semiconductor substrate" used in the following description can encompass any semiconductor-based structure that has a semiconductor surface. Wafer and structure are to be understood as including doped and undoped semiconductors, epitaxial semiconductor layers, optionally supported by a substrate, and other semiconductor structures. For example, a layer of a first semiconductor material may be grown on a growth substrate of a second semiconductor material, such as a GaAs, GaN, or Si substrate, or of an insulating material, such as on a sapphire substrate.

[0015] Depending on its intended use, a semiconductor can be based on a direct or indirect semiconductor material. Examples of semiconductor materials particularly suitable for generating electromagnetic radiation include nitride semiconductor compounds, which can produce ultraviolet, blue, or longer-wavelength light, such as GaN, InGaN, AlN, AlGaN, AlGaInN, and Al-GaInBN; phosphide semiconductor compounds, which can produce green or longer-wavelength light, such as GaAsP, AlGaInP, GaP, and AlGaP; and other semiconductor materials such as GaAs, AlGaAs, InGaAs, AlInGaAs, SiC, ZnSe, ZnO, Ga₂O₃, diamond, hexagonal BN, and combinations of these materials. The stoichiometric ratio of the compound semiconductor materials can vary. Further examples of semiconductor materials include silicon, silicon-germanium, and germanium.In the context of this description, the term "semiconductor" also includes organic semiconductor materials.

[0016] The term "substrate" generally includes insulating, conductive, or semiconductor substrates.

[0017] The term "vertical," as used in this description, refers to an orientation that is essentially perpendicular to the first surface of a substrate or semiconductor body. The vertical direction can, for example, correspond to a growth direction during the growth of layers.

[0018] The terms "lateral" and "horizontal," as used in this description, are intended to describe an orientation or alignment that is essentially parallel to a first surface of a substrate or semiconductor body. This could be, for example, the surface of a wafer or a chip (die).

[0019] The horizontal direction can, for example, lie in a plane perpendicular to a growth direction when layers are growing.

[0020] In the context of this description, the term "electrically connected" means a low-resistance electrical connection between the connected elements. The electrically connected elements do not necessarily have to be directly connected to each other. Other elements can be positioned between electrically connected elements.

[0021] The term "electrically connected" also includes tunnel contacts between the connected elements.

[0022] Fig. Figure 1 shows a schematic cross-sectional view of a general surface-emitting semiconductor laser with an ordered photonic structure or with a photonic crystal (PCSEL, "Photonic Crystal Surface Emitting Laser") to illustrate its construction and operation. The features and operating principles described here apply to the surface-emitting laser devices described below according to all examples, unless explicitly stated otherwise.

[0023] A semiconductor body 119 is arranged over a suitable substrate 100, for example, a growth substrate. The semiconductor body 119 comprises a semiconductor layer stack. The semiconductor layer stack comprises, for example, a first semiconductor layer 110 of a first conductivity type, for example, n-type, and a second semiconductor layer 120 of a second conductivity type, for example, p-type. An active zone for radiation generation 115 is arranged between the first and the second semiconductor layers 110, 120.

[0024] The active region can, for example, feature a pn junction, a double heterostructure, a single quantum well (SQW), or a multi quantum well (MQW) structure for radiation generation. The term "quantum well structure" here has no bearing on the dimensionality of the quantization. It therefore includes, among other things, quantum wells, quantum wires, and quantum dots, as well as any combination of these layers.

[0025] Additionally, a semiconductor layer with an ordered photonic structure 132 is arranged within the semiconductor body 119. In general, the term "ordered photonic structure" refers to alternating regions with different refractive indices, which can be formed, for example, by appropriately structuring a semiconductor material. For instance, holes 131 can be formed in a semiconductor material, for example, by etching. The holes 131 can be filled with a material 133 having a different refractive index than that of the surrounding semiconductor material. Furthermore, isolated semiconductor structures can be formed.

[0026] The holes or semiconductor structures can, for example, represent a lattice, such as a hexagonal lattice or another type of lattice. However, non-periodic patterns are also included, as further examples show. Furthermore, a lattice with a non-strict periodicity can also be considered an ordered photonic structure. Generally, an average spacing between the holes or semiconductor structures is specified. The position and size of the holes or structures are deterministic. A distance *a* between the individual holes or raised structures can, for example, be in the range of a quarter to half a wavelength, such as between 80 and 560 nm. The structure sizes of the ordered photonic structure 132 depend on both the refractive index and the wavelength.For example, if a dielectric material is embedded in the holes of the ordered photonic structure 132, the structure size depends on the refractive index difference. Generally, the lattice constant scales with both the wavelength and the refractive index of the material in the ordered photonic structure 132. The lattice constant can, for example, lie in a range of approximately 80 to 300 nm, or 100 to 200 nm, depending on both the wavelength and the refractive index.

[0027] The size, for example, the diameter, of the individual holes or structures can range from 40 to 150 nm. The size of the holes or dimensions in the growth direction can, for example, be greater than 100 nm, for instance, in the range of 100 to 300 nm. At a specific lateral dimension f of the ordered photonic structure 132, for example, in a range of f greater than 1 µm, a photonic crystal forms due to the ordered photonic structure. Accordingly, a photonic band structure is defined, with a specific reflection and transmission behavior depending on the wavelength. Due to the specific reflection behavior of the layer with the ordered photonic structure 132, a surface-emitting semiconductor laser is used with the [missing information - likely a specific laser type]. Fig. The layer structure shown in Figure 1 emits a wavelength determined by the photonic band structure. For example, the spacing of the holes determines the photonic band structure and thus the emission wavelength of the semiconductor laser.

[0028] In contrast to conventional vertical cavity surface-emitting lasers (VCSELs), a PCSEL does not have an optical resonator in which laser modes, determined by the resonator length, can form. Instead, in a PCSEL, the emission wavelength is determined by the photonic band structure. Accordingly, a mirror is not required to form an optical resonator, although it can be included as an optional component. Since the emission wavelength in a PCSEL is determined by the photonic band structure, laser emission occurs immediately. Unlike a VCSEL, a PCSEL does not initially exhibit spontaneous emission that is subsequently suppressed by induced emission. Consequently, such laser devices can be switched very quickly.For example, this enables pure pulse-width modulation as an operating mode. Furthermore, they can be coupled with analog control. Since the wavelength is primarily defined by the ordered photonic structure, the emission wavelength can be kept stable. For example, it is possible that the emission wavelength does not change, or changes only slightly, when the applied current or temperature changes.

[0029] Fig. Figure 2 shows a schematic cross-sectional view of a surface-emitting semiconductor laser 10 according to examples. The surface-emitting semiconductor laser comprises a support 140, for example made of a semiconductor material, an insulating or conductive material, which is selected according to the application of the semiconductor laser. An insulating layer 138 can be arranged over the support 140. A metallic mirror layer 137, for example a silver layer 137, can be arranged over the insulating layer 138. Then, a dielectric mirror layer 135 can be arranged over the metallic mirror 137.

[0030] In general, the term "dielectric mirror layer" encompasses any arrangement that reflects incident electromagnetic radiation to a high degree (e.g., >90%) and is non-conductive. For example, a dielectric mirror layer can be formed by a sequence of very thin dielectric layers, each with a different refractive index. For instance, the layers can alternate between a high refractive index (n>1.7) and a low refractive index (n<1.7) and be configured as a Bragg reflector. The layer thickness can be λ / 4, where λ represents the wavelength of the light to be reflected in the respective medium. The layer visible from the incident light can have a greater thickness, for example, 3λ / 4.

[0031] Due to its small thickness and the difference in refractive indices, the dielectric mirror layer provides high reflectivity while remaining non-conductive. This makes it suitable for isolating components of the semiconductor device. A dielectric mirror layer can, for example, contain 2 to 50 dielectric layers. The typical thickness of individual layers can range from approximately 30 to 90 nm, for example, around 50 nm. The layer stack can also contain one, two, or more layers thicker than approximately 180 nm, for example, more than 200 nm.

[0032] A second semiconductor layer 120 of a second conductivity type, for example p-type, is arranged above the dielectric mirror layer 135. An additional semiconductor layer 130 is arranged above the second semiconductor layer 120. The additional semiconductor layer 130 can, for example, also be of the second conductivity type. For example, the additional semiconductor layer 130 has the same or a different composition than the second semiconductor layer 120. An ordered photonic structure 132 is arranged in the additional semiconductor layer 130. Furthermore, a protective layer 116 is arranged above the ordered photonic structure 132. Above the protective layer 116, a first semiconductor layer 110 of a first conductivity type, for example n-type, is arranged. Furthermore, an active zone 115 is arranged between the first semiconductor layer 110 and the second semiconductor layer 120. The protective layer 116 is optional.Furthermore, for example, a growth substrate 100 can be arranged above the first semiconductor layer 110.

[0033] As in Fig. As illustrated in Figure 2, a surface-emitting semiconductor laser comprises a first semiconductor layer 110 of a first conductivity type, an active zone 115 suitable for generating electromagnetic radiation, an ordered photonic structure 132, and a second semiconductor layer 120 of a second conductivity type. The active zone 115 is located between the first and second semiconductor layers 110 and 120. As shown in Figure 2, the active zone 115 is located between the first and second semiconductor layers 110 and 120. Fig. As shown in Figure 2, the ordered photonic structure is arranged in an additional semiconductor layer 130 between the active zone 115 and the second semiconductor layer 120. Furthermore, part of the additional semiconductor layer 130 is arranged between the ordered photonic structure 132 and the second semiconductor layer 120.

[0034] As in Fig. As further shown in Figure 2, the ordered photonic structure 132 comprises a multitude of holes in the additional semiconductor layer 130. For example, the holes of the ordered photonic structure 132 can be filled with a material having a lower refractive index, such as a dielectric. For example, the additional semiconductor layer 130 can comprise a GaN-containing layer. However, the additional semiconductor layer 130 can also be selected from a different material system and contain, for example, GaAs or InP. Examples of a material for filling the holes include, for example, SiO2 or Si3N4. As shown in Fig. As further shown in Figure 2, the surface-emitting semiconductor laser 10 can also have a mirror layer 135, 137 on a side of the second semiconductor layer 120 facing away from the active zone 115.

[0035] The following describes a method for the fabrication of the surface-emitting semiconductor laser 10. Fig. Figure 3A shows a workpiece 15 which has a suitable growth substrate 100, a first semiconductor layer 110, and the active zone 115. For example, the growth substrate can be GaN, and the first semiconductor layer 110 can have GaN-containing layers. The first semiconductor layer 110 and the layers of the active zone 115 can be grown epitaxially over the growth substrate 100.

[0036] As in Fig. As shown in Figure 3B, a thin intermediate or protective layer 116, for example made of SiO, SiN, AlO, AlN, or a combination of these materials, can optionally be grown over the active zone 115. The protective layer 116 protects the layers of the active zone 115, for example, the quantum well layers of the active zone, during the subsequent structuring. The material of the intermediate layer 116 should be selected such that it can withstand the subsequent growth processes.

[0037] Then, as in Fig. As shown in Figure 3C, a hard mask layer, which may contain, for example, SiO₂ or SiN, is applied over the protective layer 116. The hard mask is then structured, for example using a lift-off process, in which the hard mask layer is applied over a structured photoresist layer. By dissolving the photoresist material in a solvent, the parts of the hard mask above the photoresist parts are removed.

[0038] Fig. Figure 3C shows an example of a resulting workpiece 15. A hard mask 117 is arranged over the surface of the optional protective layer 116. As will be explained below, in a subsequent growth process for the epitaxial growth of semiconductor material, no growth process will take place in the areas covered by the hard mask. That is, the areas covered with hard mask material define the holes to be formed in the semiconductor layer. The width and spacing of the hard mask areas are selected according to the size and spacing of the holes to be formed in the semiconductor material to be grown.

[0039] The following explains how in Fig. As shown in the 3D diagram, a method for the epitaxial growth of semiconductor layer 130 takes place. Semiconductor layer 130 can, for example, be a GaN-containing semiconductor layer. According to the diagram, the conditions during the growth of semiconductor layer 130 can be appropriately adjusted so that a flank angle is adjustable. For example, perpendicular or defined inclined flanks can be generated. This can be achieved, for example, by adjusting the pressure and temperature during the growth process. The growth conditions can also be varied during the growth of layer 130 so that a stepped sequence of different angles can be set. For example, layer 130 can be grown with a thickness that approximately corresponds to the vertical dimension of the holes to be formed. For example, the layer thickness can be 100 to 500 nm.

[0040] The hard mask can then be removed, for example by a selective etching process. Fig. Figure 3E shows an example of a cross-sectional view of a workpiece after removal of the hard mask material. If necessary, the holes can now be filled with a material with a lower refractive index, such as a dielectric. For example, the material could be SiO2 or SiN, or a mixture of these materials.

[0041] The growth of the semiconductor layer 130 is then continued. The growth parameters are modified compared to those used during the growth of the ordered photonic structure 132 as shown in Fig. 3D representation. As a result, the holes of the ordered photonic structure 132 are overgrown, so that a closed semiconductor layer 130 is formed.

[0042] Fig. Figure 3F shows an example of a resulting workpiece 15. Subsequently, further semiconductor layers are epitaxially grown to complete the semiconductor laser. For example, a second semiconductor layer 120 of a second conductivity type, such as p-type, can be grown. The second semiconductor layer 120 can in turn contain GaN.

[0043] Fig. 3G shows an example of a resulting workpiece 15.

[0044] Then, as in Fig. As illustrated in Figure 3H, a dielectric mirror layer 135 is applied. The dielectric mirror layer can, for example, contain ITO and / or NbO / SiO₂, such as alternating layers containing NbO or SiO₂. An NbO / SiO₂ mirror is particularly effective at efficiently reflecting radiation with shallow angles of incidence. Furthermore, contact holes can be formed in the dielectric mirror layer 137 to improve electrical contact with the second semiconductor layer 120. Subsequently, a metallic mirror layer 137 can be applied. For example, the metallic mirror layer 137 can contain or be made of silver. In combination with the dielectric mirror 135, the efficiency of the semiconductor laser can be significantly improved, as radiation emitted into the lower hemisphere, i.e., towards the dielectric mirror layer 135, can also be utilized.

[0045] Fig. Figure 3I shows a cross-sectional view of the resulting workpiece 15. Subsequently, an insulating layer 138, for example an oxide, can be applied. The workpiece 15 is permanently bonded to a substrate 140. The growth substrate can then be at least partially removed. For example, the growth substrate 100 can be removed by grinding and polishing or by peeling off a 2D layer such as graphene. Such methods are well known and are not described in detail here. Furthermore, a portion of the remaining growth substrate 100 and a portion of the first semiconductor layer 110 can be removed, so that a portion of a first main surface 111 of the first semiconductor layer 110 is exposed. A first contact element 112 for electrically contacting the first semiconductor layer 110 can be formed on this exposed area of ​​the first main surface 111.As a result, for example, the following can be found in . Fig. The structure shown in section 2 will be obtained.

[0046] Fig. Figure 4 shows a surface-emitting semiconductor laser, as well as other examples. The one in Fig. The surface-emitting semiconductor laser 10 shown in Figure 4 has a first semiconductor layer 110 of a first conductivity type, for example, n-type, an active zone 115 suitable for generating electromagnetic radiation, an ordered photonic structure 132, and a second semiconductor layer 120 of a second conductivity type, for example, p-type. The active zone 115 is located between the first and second semiconductor layers 110 and 120. The ordered photonic structure 132 is formed in the first semiconductor layer 110. A portion of the first semiconductor layer 110 borders the ordered photonic structure 132 on both sides. For example, the ordered photonic structure 132 can be formed by a plurality of holes in a region of the first semiconductor layer 110.

[0047] Unlike examples found, for instance, in Fig. As shown in Figure 2, the formation of the ordered photonic structure 132 in the n-conducting semiconductor layer 110 results in the advantage of a higher mobility of the charge carriers, which leads to a reduced forward voltage and a more homogeneous current distribution.

[0048] To produce the in Fig. In the surface-emitting semiconductor laser 4 shown, a first semiconductor layer 110 of a first conductivity type, for example n-type, is formed over a suitable growth substrate 100, for example a GaN substrate.

[0049] Fig. Figure 5A shows a cross-sectional view of the resulting workpiece 15. Subsequently, a hard mask 117 is formed over the first semiconductor layer 110. The hard mask can be formed using a lift-off process or by etching using a structured photoresist mask.

[0050] Fig. Figure 5B shows a cross-sectional view of the resulting workpiece 15. Subsequently, an epitaxial growth process is carried out to further grow the first semiconductor layer 110. Due to the formation of the structured hard mask, the areas of the surface of layer 110 where no layer growth occurs are covered by the hard mask 117, so that holes form in the resulting layer. The growing conditions of the semiconductor material, in particular pressure and temperature, determine the flank angle. Accordingly, perpendicular or defined inclined flanks can be generated. By changing the conditions, a stepped sequence of different angles can be achieved.

[0051] Fig. Figure 5C shows an example of a resulting workpiece 15. Subsequently, for example, by changing the growth conditions, the first semiconductor layer 110 can be grown in such a way that the layer over the holes in the ordered photonic structure 132 is closed. For example, the hard mask can be overgrown during this growth process. Subsequently, the active zone 115 is formed, for example by depositing the corresponding layers.

[0052] Fig. Figure 5E shows a cross-sectional view of the resulting workpiece. Subsequently, the second semiconductor layer 120 of the second conductivity type, for example p-type, is grown. Fig. Figure 5F shows a cross-sectional view of a resulting workpiece 15. Subsequently, the dielectric mirror layer 135 and the metallic mirror layer 137 can be formed over the second semiconductor layer 120. This can be done, for example, in the manner described with reference to Fig. 3H as described, can be carried out. As a result, for example, the following can be achieved: Fig. 4 surface-emitting semiconductor laser structures are obtained.

[0053] For example, electrical contacts can be formed starting from the in Fig. In the structure shown in Figure 6A, a portion of the epitaxially grown layers can be removed, for example, by etching. The etch depth can be measured such that the ordered photonic structure is removed. As a result, a region of a first principal surface 111 of the first semiconductor layer 110 is exposed. This is shown in Fig. Figure 6B illustrates this. A first contact element 112 can be formed over the first main surface 111 of the first semiconductor layer 110. Furthermore, a portion of the dielectric mirror layer 135 and the metallic mirror layer 137 can be removed, exposing a portion of the first main surface 121 of the second semiconductor layer 120. The second contact element 122 can then be formed over this exposed portion.

[0054] As in Fig. As shown in Figure 6C, the surface-emitting semiconductor laser 10 can then be applied to a suitable support (not shown), wherein, for example, the metallic mirror layer 137 is arranged between the semiconductor laser 10 and the support. For example, corresponding contacts can be provided on this support. Emission of the generated electromagnetic radiation 20 can occur via the first semiconductor layer 110 and, optionally, the substrate 100. This is shown in Figure 6C. Fig. 6C illustrates this. Examples shown in Fig. In the images shown in 6C, the ordered photonic structure 132 is further away from the active zone 115 than in examples shown, for instance, in Fig. 6A or Fig. Figure 6B shows that, as a result, the active zone can be grown with better epitaxial quality.

[0055] Alternatively, starting from the in Fig. In the structure shown in Figure 6A, the first contact element 112 is also placed above the ordered photonic structure 132. This is shown in Figure 6A. Fig. 6D illustrated. As in Fig. As shown in Figure 6D, the layers over a portion of the first main surface 111 of the semiconductor layer 110 are back-etched. The first semiconductor layer 110 is only minimally etched, so that the ordered photonic structure 132 is retained. Furthermore, a second contact element 122 can be formed over the metallic mirror layer 137. In this case, for example, the second semiconductor layer 120 can be contacted via via contacts 139 extending through the dielectric mirror layer 135.

[0056] The surface-emitting semiconductor laser 10 can be applied to a suitable substrate, such that, for example, the second contact element 122 is adjacent to the substrate. In this case, the generated electromagnetic radiation 20 is emitted via the first semiconductor layer 110 and, if applicable, the growth substrate 100, as shown in Fig. 6E is indicated.

[0057] Examples that can be found, for instance, in the Fig. 6D and Fig. As shown in Figure 6E, the distance between the ordered photonic structure 132 and the active zone 115 is smaller than in examples shown, for instance, in Fig. 6C are shown. As a result, the effect of the ordered photonic structure on light emission in the active zone can be amplified.

[0058] The in the Fig. 6B and Fig. The contact options specified in 6D can be combined. For example, the one in Fig. 6B shows the first contact element 112 with the one in Fig. The second contact element 122 shown in 6D can be combined and vice versa.

[0059] Fig. Section 7 summarizes a method according to examples. A method for fabricating a surface-emitting semiconductor laser comprises forming (S100) a first semiconductor layer of a first conductivity type over a growth substrate, forming (S110) a hard mask layer over the first semiconductor layer, and structuring (S120) the hard mask layer such that areas of a surface of a semiconductor layer adjacent to the hard mask layer are exposed and suitable for defining an ordered photonic structure in a subsequently grown additional semiconductor material.The process further comprises growing (S130) the additional semiconductor material over the exposed areas of the semiconductor layer adjacent to the hard mask layer, removing (S140) the hard mask layer, leaving grown structured semiconductor regions and forming an ordered photonic structure, and growing (S150) the additional semiconductor material, whereby the structured semiconductor regions are overgrown with the additional semiconductor material. The process further comprises forming (S160) an active zone capable of generating electromagnetic radiation.

[0060] For example, the active zone can be formed before the hard mask layer is formed. In this case, the additional semiconductor material can represent a second semiconductor layer of a second conductivity type.

[0061] For example, the hard mask layer is formed adjacent to the active zone. However, the process can also include the formation of an intermediate layer after the active zone has been formed. In this case, the hard mask layer can be formed adjacent to the intermediate layer.

[0062] According to further examples, the active zone can be formed after the growth of the additional semiconductor material. In this case, for example, the hard mask layer can be formed adjacent to the first semiconductor layer. The process can further include the formation (S170) of a second semiconductor layer of a second conductivity type.

[0063] The method described here enables the fabrication of an ordered photonic structure with high precision. In particular, the required feature size for applications in the blue or green spectral range of the GaN material system can be produced with high accuracy. Consequently, a surface-emitting laser with an ordered photonic structure can also be realized for the GaN material system. Thus, a surface-emitting semiconductor laser in the blue or green spectral range can be provided without the need for epitaxial growth of suitable mirror layers.

[0064] The structuring of the ordered photonic structure is determined by the structuring of the hard mask. For example, the hard mask can be structured into a multitude of possible patterns. For instance, the hard mask can be structured in such a way that any deviations from a strictly periodic pattern are generated. Such deviations include, for example, deviations from a strictly periodic arrangement position or different diameters of the generated holes. Furthermore, it is possible to structure a workpiece in such a way that a multitude of adjacent, different ordered photonic structures are generated.

[0065] Fig. Figure 8A shows a top view of a surface-emitting semiconductor laser, as shown in further examples. As in Fig. As shown in Figure 8A, the surface-emitting semiconductor laser has a variety of image elements 1421, 1422, ..., 142 n on.

[0066] Fig. Figure 8B shows a cross-sectional view through the surface-emitting semiconductor laser according to examples. As in Fig. As shown in Figure 8B, each of the image elements 1421, 1422, 1423 comprises a first semiconductor layer 110 of a first conductivity type, an active zone 115 capable of generating electromagnetic radiation, an ordered photonic structure 1451, 1452, 1453, and a second semiconductor layer 120 of a second conductivity type. The active zone 115 is located between the first and second semiconductor layers 110, 120. The ordered photonic structure 1451, 1452, 1453 is located between the active zone 115 and either the first or the second semiconductor layer 110, 120. Furthermore, the ordered photonic structure 1451 of a first image element 1421 differs from the ordered photonic structure 1452 of a second image element 1422.

[0067] The first and second semiconductor layers 110, 120 and the active zone 115 can each be assigned to a plurality of image elements 142.

[0068] For example, the ordered photonic structure 1451, 1452, 1453 is each arranged in a part of the first semiconductor layer 110, and a part of the first semiconductor layer 110 is adjacent to both sides of the ordered photonic structure 1451, 1452, 1453 or is arranged on a side of the ordered photonic structure 1451, 1452, 1453 facing away from the second semiconductor layer 120. According to further examples, the ordered photonic structure 1451, 1452, 1453 is arranged in a part of the second semiconductor layer 120, and a part of the second semiconductor layer 120 is adjacent to both sides of the ordered photonic structure 1451, 1452, 1453 or is arranged on a side of the ordered photonic structure 1451, 1452, 1453 facing away from the first semiconductor layer 110.

[0069] As in Fig. As shown in Figure 8B, the ordered photonic structure 1451 differs from the ordered photonic structure 1452. Furthermore, the second ordered photonic structure 1452 differs from the ordered photonic structure 1453. Accordingly, the emission characteristic 1531 of the first image element 1421 differs from the emission characteristic 1532 of the second image element 1422. Furthermore, the emission characteristic 1532 of the second image element 1422 differs from the emission characteristic 1533 of the third image element 1423.

[0070] The phrase "a first ordered photonic structure is different from a second photonic structure" can mean that the positions of the generated holes may be locally shifted. For example, the periodicity of the arranged holes may be maintained, but predetermined holes are shifted relative to their predetermined arrangement position. According to further examples, this can also mean that the size or shape of the holes is changed without, for example, a change in the predetermined spacing.

[0071] For example, a lateral dimension of the image elements can be larger than 10 µm.

[0072] Because the ordered photonic structures of at least two image elements are different from each other, a different emission characteristic can be generated by each of the corresponding image elements. More precisely, the individual areas emit light in different directions. This allows higher intensities to be achieved at the edge of the illumination area compared to components with, for example, uniformly ordered photonic structures. The emission direction within the semiconductor chip is defined by the specific geometry of the photonic structure 132. In particular, the lattice constant as well as the shape and size of the individual structural elements determine the respective emission characteristic.As a result, for example when using a large number of image elements, each with different ordered photonic structures, collimated emission into any desired solid angle can be achieved using the surface-emitting semiconductor laser 10. Emission occurs directly from the chip without additional losses. Accordingly, it is possible to achieve uniform illumination of a specific field of view without additional beam-shaping optics. In particular, the intensity profile is realized with steep slopes.

[0073] This is, for example, in Fig. Figure 8C illustrates this, showing the intensity as a function of the x-coordinate. In contrast to conventional intensity profiles, the intensity at the edge of the laser does not decrease gradually, but rather in steps. As a result, the maximum illumination intensity is obtained at the edge of the laser. Consequently, the light emitted from the surface of the semiconductor laser can be almost perfectly pre-collimated in a vertical direction.

[0074] As shown in the examples, the semiconductor laser 10 can be combined with an optical element 105, resulting in a laser device 25. The optical element can, for example, be mounted directly onto the chip or via an air gap or adhesive in a housing with the surface-emitting semiconductor laser. Examples of optical elements include, for example, optically diffracting or refracting elements, metal lenses, or any lens arrangement. By perfectly pre-collimating the emission from the surface-emitting semiconductor laser, any desired intensity profile can be perfectly achieved with conventional optical elements 105. This is demonstrated in Fig. 8D illustrated.

[0075] As described above, a very flat and compact lighting device can thus be provided. A lighting device containing the described surface-emitting semiconductor laser can be used, for example, as a general lighting device, for measurements such as time-of-flight (ToF) measurements, or even for facial recognition methods.

[0076] In particular, if the surface-emitting semiconductor laser described here is manufactured using the method described in the Fig. As explained in sections 3A to 7, a different ordered photonic structure for a large number of image elements can be easily produced, namely by suitable structuring of the hard mask 117 as for example in Fig. 3C shown.

[0077] The following describes embodiments in which arrangements of highly miniaturized surface-emitting semiconductor laser elements are combined with an ordered photonic structure.

[0078] Fig. Figure 9A shows a laser device 25 with an arrangement of a plurality of surface-emitting semiconductor laser elements 1481, 1482, 1483 according to embodiments. Each of the semiconductor laser elements 1481, 1482, 1483 comprises a first semiconductor layer 110 of a first conductivity type, for example n-type, and an active zone 115 suitable for generating electromagnetic radiation. The arrangement further comprises an ordered photonic structure 132, a second semiconductor layer 120 of a second conductivity type, and a first and second contact element 112, 122. The ordered photonic structure 132 and the second semiconductor layer are associated with at least two semiconductor laser elements 1481, 1482. The second contact element is electrically connected to the second semiconductor layer 120, and the active zone is arranged between the first semiconductor layer 110 and the second semiconductor layer 120.The ordered photonic structure 132 is arranged between the active zone 115 and the second contact element 122. For example, the second semiconductor layer 120 is directly adjacent to or located near the second contact element 122.

[0079] As previously described, the ordered photonic structure 132 requires a certain minimum size in the lateral direction, for example, more than 1 µm, so that the photonic band structure can form. Conversely, for certain applications, such as p-displays, it may be necessary to use particularly small laser elements 1481. In this case, an ordered photonic structure 132 can be associated with several laser elements 148. For example, a horizontal dimension d of the semiconductor laser elements can be less than 10 µm. A horizontal dimension f of the ordered photonic structure is greater than 10 µm. For example, the horizontal dimension d of the semiconductor laser elements 148 can be less than 1 µm, for example, 200 to 500 nm. For example, together with the ordered photonic structure 132, the second semiconductor layer 120 can be associated with several laser elements 148.

[0080] Furthermore, the second contact element 122 can be assigned to several laser elements 148. According to further embodiments, it is also possible that a second contact element 122 is provided for each laser element 148. Each individual laser element 148 can be controlled via an associated first contact element 1121, 1122, 1123. For example, the individual first contact elements 112 can be configured as mirrors and may contain a metallic reflective material to increase laser efficiency. For example, each of the contact elements 112 can contain a layer stack comprising metal and ITO (indium tin oxide). According to embodiments, the ordered photonic structure 132 can vary along a horizontal direction, for example, the x- or y-direction. As a result, a broader wavelength distribution from the active part of the pixel can be achieved.More precisely, the full width at half maximum (FWHM) can be several nm, which minimizes interference effects.

[0081] The distance s between adjacent laser elements 148 can, for example, be greater than 1 µm or even greater than 2 µm. According to further embodiments, adjacent laser elements 148 can also be directly adjacent to one another. In this case, for example, a smooth transition of the emission characteristics can occur. The active part d of the laser element 148 can be less than 1 µm. The dimension f of the ordered photonic structure 132 can be greater than 10 µm, for example, greater than 100 µm. Accordingly, the ordered photonic structure 132 extends over several pixels. With the described setup, a small pixel pitch can be achieved.

[0082] Furthermore, can a desired narrow emission characteristic be set for the entire laser device by a suitable design of the ordered photonic structure 132?

[0083] Fig. Figure 9B shows a top view of the laser device. The individual laser elements 1481, 1482 are indicated by dashed lines.

[0084] Fig. Figure 9C shows a schematic cross-sectional view of the laser device 25 according to further embodiments. In contrast to the one shown in Fig. In the structure shown in Figure 9A, the laser device additionally features a filler material 125 between the active zones 115 of the individual laser elements 1481, 1482, 1483. Further components are analogous to those shown in Figure 9A. Fig. Figure 9A illustrates this. The filler material 125 can have a similar refractive index to the active zone 115. For example, the filler material can be the same or a very similar material to that of the active zone 115. However, the active zone 115 is insulated from the filler material 125 to suppress crosstalk with neighboring laser elements. The individual laser elements 1481, 1482, 1483 can each be individually controlled via the second contact elements 1121, 1122, 1123, thus preventing current distribution to neighboring pixels. Due to the presence of the filler material, the functionality of the photonic crystal or ordered photonic structure 132 can be improved.

[0085] As described, this provides a laser device with an array of surface-emitting semiconductor laser elements, achieving a narrow beam pattern and high system efficiency. The laser device can be used for a micro-display, for example, for augmented reality (AR) applications.

[0086] Fig. Figure 10A shows a lighting device 30 according to embodiments. The lighting device 30 has several laser devices 251, 252, 253, each of which is suitable for emitting light of different wavelengths, for example, red, green, blue. Each of the laser devices 251, 252, 253 can, for example, be configured as shown in the Fig. The laser devices are set up as shown in Figures 9A to 9C. The material system of each laser device is selected such that electromagnetic radiation of a specified color is emitted. Each of the laser devices 251, 252, 253 is assigned its own waveguide. The first waveguide 101, for example, has an input coupling element and an output coupling element 108. Similarly, the second and third waveguides each have an input coupling element 107 and an output coupling element 108. The first, second, and third laser devices 251, 252, and 253 are arranged adjacent to each other in the horizontal direction (x-direction). The first, second, and third waveguide elements 101, 102, 103 are arranged one above the other in the vertical direction (z-direction), for example. The second waveguide does not cover a portion of the first waveguide 101 that overlaps with the first laser device 251.A coupling structure 107, for example a suitable grid or other suitable coupling structure, is provided on the exposed area of ​​the first waveguide 101. Similarly, an area of ​​the second waveguide 102, opposite the second laser device 252, is not covered. A corresponding coupling element 107 is also present in this area. An area of ​​the third waveguide 103, opposite the third laser device 253, also has a coupling element 107.

[0087] In this way, electromagnetic radiation, for example emitted by the first laser device 251, can be coupled into the first waveguide 101. At the other end of each waveguide is an output coupling element 108. Here, the output coupling elements 108 of the first waveguide 101, the second waveguide 102, and the third waveguide 103 are arranged one above the other, so that the coupled-out light components are superimposed. As a result, a combined beam 21 is output, containing emitted radiation from the first laser device 251, the second laser device 252, and the third laser device 253. In this way, an RGB image can be generated by modulating the individual laser devices. Due to the high intensity, the corresponding laser devices can also be combined with lossy optical systems.

[0088] The arrangement, which is found, for example, in Fig. As shown in Figure 10A, a very high intensity of the emitted electromagnetic radiation 20 can be achieved. Due to the special structure of the individual laser devices 251, 252, each with an ordered photonic structure 132, it is possible to switch the laser devices very quickly, since spontaneous emission is suppressed here due to the different wavelength selection mechanism. The arrangement can be used in a display device, for example a micro-display, especially for AR applications.

[0089] Fig. Figure 10B shows a system with a laser device 25, as for example in one of the Fig. Figures 9A to 9C show a microelectromechanical system 35, for example, for deflecting the generated electromagnetic radiation 20. Using the microelectromechanical system 35, the field of view of the laser device 25 can be enlarged. Due to the high intensity of the radiation 20 emitted by the laser device 25, the intensity remains sufficient even with an enlarged field of view. Because of the high quality of the emitted radiation 20, a very high resolution can be achieved with this approach.

[0090] A system with the laser device that is in the Fig. 9A to 9C, 10A, 10B shown, could be, for example, a display device.

[0091] According to further embodiments, the ordered photonic structure 132 can be formed within an n-type semiconductor layer 114. This allows for increased charge carrier mobility within the ordered photonic structure 132. As a result, the forward voltage is reduced and the current distribution can be made more homogeneous.

[0092] Fig. Figure 11A shows a cross-sectional view through a laser device 25 according to embodiments. The laser device 25 has an arrangement of a plurality of semiconductor laser elements 1481, 1482, ... 1483, each of which has a first semiconductor layer of the first conductivity type 110 and an active zone 115. A first contact element 112 is arranged with the first semiconductor layer 110 of each of the semiconductor laser elements 1481, 1482, 1483. Unlike, for example, in Fig. As shown in Figure 9A, the second semiconductor layer 120 borders the active zone 115. The ordered photonic structure 132 is formed in a third semiconductor layer 114 of the first conductivity type. The third semiconductor layer 114 is, for example, directly adjacent to or located near the second contact element 122. The second semiconductor layer 120 is connected to the third semiconductor layer 114 via a tunnel contact 127. The tunnel contact 127 has a highly doped layer 128 of the second conductivity type, for example, p ++ -conducting, as well as a highly doped layer 129 of the first conductivity type, for example n ++ -leading, on.

[0093] The p ++ -doped layer 128 as well as the n ++ The -doped layer 129 and optionally an intermediate layer (not shown) form a tunnel diode or a tunnel junction 127. The n ++The doped layer 129 of the tunnel junction 127 is electrically connected to the positive electrode or the second contact element 122 via the first-type conductivity layer 114. Through the tunnel junction 127, whose n-side is connected to the positive electrode or the second contact element 122, holes are injected into the region of the active zone 115. There, the injected holes recombine with the electrons supplied by the negative electrode or the first contact element 112, emitting photons.

[0094] As in Fig. As shown in 11A, the tunnel junction 127, as well as the ordered photonic structure 132, the third semiconductor layer 114 and the second semiconductor layer 120, are assigned to a plurality of semiconductor laser elements 1481, 1482, 1483.

[0095] According to further embodiments, the tunnel transition 127 can also extend partially into the ordered photonic structure 132. For example, the tunnel transition 127 can lie within the ordered photonic structure 132. For example, layers of the ordered photonic structure 132 can form a tunnel transition. According to further embodiments, the tunnel transition can also lie above the ordered photonic structure 132. According to further embodiments, the tunnel transition can also lie between the active zone 115 and the ordered photonic structure 132.

[0096] Fig. Figure 11B shows a schematic cross-sectional view of a laser device 25 according to further embodiments. In addition to the ones shown in Fig. In addition to the components shown in Figure 11A, the laser device 25 also has a reflection-reducing layer 123, for example an ITO layer or another suitable layer, which reduces the reflection of the generated electromagnetic radiation 20 at the interface between the third semiconductor layer 114 and air. As a result, the intensity of the emitted radiation is increased. For example, according to embodiments, the second contact element 122 is directly adjacent to the reflection-reducing layer 123. The reflection-reducing layer 123 is directly adjacent to the third semiconductor layer 114.

[0097] Fig. Figure 11C shows a schematic cross-sectional view of a laser device 25 according to further examples. In contrast to the one shown in the Fig. 11A and Fig. In the laser device 25 shown in Figure 11B, the laser device 25 does not have a plurality of individual laser elements 1481, 1482, 1483 to which a common ordered photonic structure 132 is assigned. Rather, a single semiconductor laser element is assigned to the photonic structure 132. For example, the semiconductor laser element can have a dimension in the range of 1 µm or larger. The ordered photonic structure 132 can have a lateral dimension that is larger than that of the semiconductor laser element.

[0098] Fig. Figure 11D shows a cross-sectional view of a laser device 25 according to further examples. In contrast to the semiconductor devices shown in the Fig. As illustrated in Figures 11A to 11C, the ordered photonic structure 132 is formed in the first semiconductor layer 110 of the first conductivity type. The first contact element 112 is arranged adjacent to the first semiconductor layer 110. The active zone 115 is formed adjacent to the first semiconductor layer 110. Furthermore, the second semiconductor layer 120 is formed adjacent to the active zone 115. A tunnel junction 127 is suitable for connecting the second semiconductor layer 120 with the third semiconductor layer 114 of the first conductivity type. Furthermore, a reflection-reducing layer 123 can be provided on the top surface of the third semiconductor layer 114. Also in the Fig. In the example shown in Figure 11D, the ordered photonic structure 132 is formed in a semiconductor layer of the first conductivity type, for example n-type.

[0099] As in the Fig. 11C and Fig. As shown in Figure 11D, a surface-emitting semiconductor laser comprises a first n-doped semiconductor layer 110, an ordered photonic structure 132, and an active zone 115 capable of generating electromagnetic radiation. The surface-emitting semiconductor laser further comprises a second p-doped semiconductor layer 120 and a third n-doped semiconductor layer 114.

[0100] The surface-emitting semiconductor laser further comprises a tunnel junction 127, which is suitable for electrically connecting the second p-doped semiconductor layer 120 with the third n-doped semiconductor layer 114. The active zone 115 is arranged between the second p-doped semiconductor layer 120 and the first n-doped semiconductor layer 110. The ordered photonic structure 132 is formed in the first or the third n-doped semiconductor layer 110, 114.

[0101] The embodiments described here can be further modified, particularly taking into account the features described in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9 to Fig. The structures described in section 10 can be modified. For example, the ordered photonic structure, as described in [reference], can be modified. Fig. 8A to 8C, combined with a tunnel crossing 127. More precisely, in the Fig. In the structure shown in Figure 8B, the ordered photonic structure 1451, 1452, 1453 is each formed in a semiconductor layer of the first conductivity type. The electrical contact to a second contact element 122 can be made via a tunnel contact 127.

[0102] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that the specific embodiments shown and described can be replaced by a multitude of alternative and / or equivalent embodiments without departing from the scope of protection of the invention. The application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is limited only by the claims and their equivalents. REFERENCE MARK LIST 10 Surface-emitting semiconductor lasers 15 workpieces 20 electromagnetic radiation 21 Combined beam 25, 251, 252, 253 Laser device 30 Lighting device 35 microelectromechanical system 40 objects to be illuminated 100 substrate 101 first waveguide 102 second waveguide 103 third waveguide 105 optical element 107 Coupling element 108 Disconnect element 110 first semiconductor layer 111 first main surface of the first semiconductor layer 112, 1121, 1122, 1123 first contact element 114 third semiconductor layer 115 active zone 116 Protective layer 117 Hard mask 119 Semiconductor bodies 120 second semiconductor layer 122 second contact element 123 reflection-reducing layer 125 Filling material 127 Tunnel crossing 128 first semiconductor layer of the tunnel junction 129 second semiconductor layer of the tunnel junction 130 semiconductor layer 131 holes 132 ordered photonic structure 133 dielectric material 135 dielectric mirror layer 137 metallic mirror layer 138 insulating layer 139 Via contact 140 carriers 142, 1421, 1422 Image element 144 mirrors 145, 1451, 1452 ordered photonic structure 148, 1481, 1482, 1483 Semiconductor laser element 1531, 1532 Radiation characteristic

Claims

[1] Laser device (25) with an arrangement of a plurality of surface-emitting semiconductor laser elements (1481, 1482, 1483), wherein each of the semiconductor laser elements (148) comprises the following: a first semiconductor layer (110) of a first conductivity type; and an active zone (115) suitable for generating electromagnetic radiation (20); wherein the arrangement further an ordered photonic structure (132); a second semiconductor layer (120) of a second conductivity type, comprising a first and a second contact element (112, 122), wherein the ordered photonic structure (132) and the second semiconductor layer (122) are associated with at least two semiconductor laser elements (1481, 1482), wherein a horizontal dimension of the semiconductor laser elements (148, 1481, 1482, 1483) is each less than 10 µm and a horizontal dimension of the ordered photonic structure (132) is greater than 10 µm, the second contact element (122) is electrically connected to the second semiconductor layer (120), wherein the active zone (115) is arranged between the first semiconductor layer (110) and the second semiconductor layer (120), the ordered photonic structure (132) is arranged between the active zone (115) and the second contact element (122). [2] Laser device (25) according to claim 1, wherein the active zones (115) of the individual semiconductor laser elements (148, 1481, 1482, 1483) are electrically insulated from each other and a filler material (125) is arranged in an intermediate space between adjacent semiconductor laser elements (148, 1481, 1482, 1483). [3] Laser device (25) according to claim 1 or 2, wherein the second semiconductor layer (120) is adjacent to the second contact element (122) and the ordered photonic structure (132) is arranged in the second semiconductor layer (120). [4] Laser device (25) according to claim 1 or 2, further comprising a third semiconductor layer (114) of the first conductivity type adjacent to the second contact element (122), and a tunnel junction (127) suitable for electrically connecting the second semiconductor layer (120) to the third semiconductor layer (114), wherein the ordered photonic structure (132) is arranged in the third semiconductor layer (114). [5] µ-display device comprising the laser device according to any one of claims 1 to 4. [6] µ-display device according to claim 5, which is an AR display device.

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