Semiconductor laser and method for producing a semiconductor laser

Abstract

The invention relates to a semiconductor laser (1) comprising a semiconductor body (2) having an active region (20) for generating radiation (8) and an optical interaction structure (3) having structure elements (30), wherein at least some of the structure elements (30) are arranged at mutually different nominal center-to-center distances (35) from one another in such a way that, during operation of the semiconductor laser (1) at a specified operating point, local temperature differences in the optical interaction structure (3) reduce differences between the optical path lengths (39) associated with the nominal center-to-center distances (35) between said structure elements (30). The invention furthermore relates to a method for producing a semiconductor laser (1).

Description

[0001] 2024PF00462 August 29, 2025

[0002] P2024 , 0542 WO N

[0003] - 1 -

[0004] Description

[0005] Semiconductor laser and method for manufacturing a semiconductor laser

[0006] The present application relates to a semiconductor laser and a method for manufacturing a semiconductor laser.

[0007] Periodic lattice structures can be used in semiconductor lasers to selectively favor or disfavor radiation of a specific wavelength. However, temperature fluctuations within the semiconductor laser can lead to local mismatches in the structure, reducing the efficiency of the desired interaction. This can impair the performance of the semiconductor laser.

[0008] One task is to specify a semiconductor laser that exhibits improved properties when local temperature differences occur during operation. Furthermore, a method for reliably manufacturing such a semiconductor laser should be specified.

[0009] This task is solved, among other things, by a semiconductor laser or a method according to the independent patent claims. Further embodiments and advantages are the subject of the dependent patent claims.

[0010] A semiconductor laser is specified. In particular, the semiconductor layer comprises a semiconductor body with an active region for generating radiation. For example, the semiconductor body is part of a semiconductor chip, which is used in the 2024PF00462 29. August 2025 P2024 , 0542 WO N

[0011] 2

[0012] It is manufactured by singulating a wafer with an epitaxial sequence of semiconductor layers. In particular, the semiconductor body itself is free of a casing.

[0013] For example, the active region is part of an epitaxial semiconductor layer sequence. For example, the active region is located between a first semiconductor layer of a first conductor type and a second semiconductor layer of a second conductor type different from the first conductor type, such that the active region is located in a pn junction.

[0014] The active area, for example, features a II-IV compound semiconductor material.

[0015] II IV compound semiconductor materials are used for radiation generation in the ultraviolet (Al x In y Gai- x-y N) over the visible (Al x In y Gai- X-y N, especially for blue to green radiation, or Al x In yGai- X-y P, especially for yellow to red radiation) up to the infrared (Al x In y Gai- X-y The spectral range is particularly suitable. Here, 0 < x < 1, 0 < y < 1 and x + y < 1 apply, especially with x ≤ 1, y ≤ 1, x ≤ 0 and / or y ≤ 0. High internal quantum efficiencies can also be achieved in radiation generation with II-IV compound semiconductor materials, especially from the aforementioned material systems.

[0016] The active region includes, for example, a quantum structure. Within the scope of the application, the term quantum structure includes, in particular, any structure in which charge carriers are confined by 2024PF00462 29 August 2025 P2024 , 0542 WO N

[0017] 3

[0018] They can experience the quantization of their energy states.

[0019] In particular, the term quantum structure does not include any information about the dimensionality of the quantization. It therefore encompasses, among other things, quantum wells, quantum wires, quantum rods, and quantum dots, and any combination of these structures.

[0020] According to at least one embodiment of the semiconductor laser, the semiconductor laser has an optical interaction structure with structural elements.

[0021] In particular, an optical interaction structure is a structure that acts in a wavelength-selective manner for radiation propagating in a semiconductor laser resonator due to diffraction and / or optical interference effects. For example, the optical interaction structure is designed to selectively favor or disfavor certain wavelengths in the propagation within the semiconductor material of the resonator, or to couple them out of the resonator. For example, the optical interaction structure can act as a wavelength-selective, spatially distributed mirror.

[0022] The structural elements can be arranged along one spatial direction, or along two spatial directions, particularly those perpendicular or oblique to each other, or along three spatial directions, for example in the form of a one-dimensional, two-dimensional, or three-dimensional photonic crystal. For example, the optical interaction structure is designed in the form of a one-dimensional or two-dimensional lattice, wherein it is located in the semiconductor body of the semiconductor laser or in a structure on the 2024PF00462 29 August 2025

[0023] P2024 , 0542 WO N

[0024] 4

[0025] The semiconductor body has raised areas and / or depressions arranged in a layer or sequence of layers.

[0026] Alternatively or additionally, the optical interaction structure can be formed by a sequence of layers with different refractive indices.

[0027] For example, at least one spatial direction along which the structural elements are arranged side by side runs parallel to a main propagation direction of the radiation propagating within the resonator of the semiconductor laser.

[0028] According to at least one embodiment of the semiconductor laser, at least some of the structural elements are arranged along a spatial direction at different nominal center distances from one another. Thus, the structural elements do not form a completely periodic structure, at least along this spatial direction. The nominal center distances can be defined during the fabrication of the semiconductor laser, for example, by appropriate spacing in a lithography mask.

[0029] In particular, the structural elements are arranged such that, during operation of the semiconductor laser at a given operating point, local temperature differences in the optical interaction structure reduce differences between the optical path lengths associated with the nominal center distances of these structural elements.

[0030] The optical path length at the operating point is calculated as the product of the center-to-center distance of the structural elements and the refractive index in the region of the structural elements, where 2024PF00462 29 August 2025

[0031] P2024 , 0542 WO N

[0032] - 5 - the center distance and the refractive index are to be used at the local temperature at the operating point.

[0033] In other words, locally occurring differences in thermal expansion and / or refractive index during the operation of the semiconductor laser are at least partially compensated by the fact that the structural elements are specifically arranged at different nominal center distances during the manufacture of the semiconductor laser.

[0034] The local temperatures refer specifically to a thermal equilibrium state in which the temperature of the optical interaction structure does not change, or at least not significantly, over time during operation. For example, the semiconductor laser is designed for continuous wave operation.

[0035] In at least one embodiment, the semiconductor laser has a semiconductor body with an active region for generating radiation and an optical interaction structure with structural elements, wherein at least some of the structural elements are arranged at different nominal center distances to each other such that, when the semiconductor laser is operated at a given operating point, local temperature differences in the optical interaction structure reduce differences between the optical path lengths that are assigned to the nominal center distances of these structural elements.

[0036] Contrary to the usual approach of optimizing heat dissipation to minimize temperature differences within the semiconductor laser during operation, the 2024PF00462 was developed on August 29, 2025.

[0037] P2024 , 0542 WO N

[0038] - 6 -

[0039] Because temperature differences are inherent in the semiconductor body, they can be deliberately accepted and taken into account during the fabrication of the optical interaction structure of the described semiconductor laser. This allows for the use of a mounting geometry and / or cooling arrangement that, by design, creates a temperature gradient within the semiconductor body. This increases the design freedom for the assembly technology and / or cooling of the semiconductor laser while simultaneously ensuring high efficiency. For example, the production of particularly compact and / or cost-effective semiconductor lasers can be simplified.

[0040] According to at least one embodiment of the semiconductor laser, the relative difference between the optical path lengths at the operating point is smaller for at least some of the structural elements than the relative difference between the corresponding assigned nominal center distances. The local temperature difference during operation of the semiconductor laser thus causes the optical path lengths at the operating point to converge. While temperature differences in conventional, nominally periodically arranged interaction structures cause a mismatch and associated efficiency losses, the maximum efficiency of the optical interaction structure of the described semiconductor laser is achieved precisely because the temperature differences taken into account during the fabrication of the semiconductor laser occur at the operating point.

[0041] Ideally, the optical path lengths assigned to the center distances along a spatial direction are for all 2024PF00462 29. August 2025

[0042] P2024 , 0542 WO N

[0043] 7

[0044] The structural elements must be identical, resulting in a periodic optical interaction structure with respect to the optical path lengths at the operating point. However, an improvement in efficiency is also achieved if this criterion is at least approximately met.

[0045] According to at least one embodiment of the semiconductor laser, the optical interaction structure exhibits a temperature gradient along a propagation direction of the radiation within a resonator during operation. For example, the temperature of the optical interaction structure increases continuously along a direction. At the operating point, for instance, the temperature of the optical interaction structure increases towards a radiation exit side of the semiconductor laser. In this case, the nominal center-to-center distances of the structural elements can decrease with decreasing distance towards the radiation exit side, for example, continuously. These smaller nominal center-to-center distances can be compensated for during operation by the locally higher refractive index and the locally greater thermal expansion.

[0046] In general, the structural elements of the optical interaction structure can be arranged during the fabrication of the semiconductor laser such that the structural elements in areas where higher temperatures are expected during operation are arranged at smaller nominal center distances from each other than in areas where lower temperatures are expected during operation. 2024PF00462 29 August 2025

[0047] P2024 , 0542 WO N

[0048] - 8 -

[0049] According to at least one embodiment of the semiconductor laser, the semiconductor body is arranged on an intermediate support (or submount). For example, the intermediate support may be made of or consist of a metal. Electrical contact between the semiconductor body and the submount is achieved, for example, through the submount material. Alternatively, the submount may be made of a ceramic, optionally with an electrically conductive coating for electrical contact with the semiconductor body.

[0050] For example, contacts for the external electrical connection of the semiconductor laser are arranged on the intermediate substrate. Each contact can be electrically connected to the semiconductor body via a bonding layer and / or a connecting wire such as a bond wire.

[0051] The propagation direction of the radiation in the resonator of the semiconductor laser can be arranged parallel, oblique or perpendicular to a principal extension plane of the intermediate carrier.

[0052] According to at least one embodiment of the semiconductor laser, the intermediate support on a side facing away from the radiation emission side of the semiconductor body has a lower temperature during operation of the semiconductor laser than on a side of the semiconductor body facing the radiation emission side. For example, in this case, the semiconductor laser is an edge-emitting semiconductor laser, in which the temperature of the intermediate support directly below the radiation emission side is higher during operation of the semiconductor laser than directly below the emission side. 2024PF00462 29 August 2025

[0053] P2024 , 0542 WO N

[0054] - 9 -

[0055] Radiation exit side opposite side of the semiconductor body.

[0056] According to at least one embodiment of the semiconductor laser, the intermediate support is designed for cooling by a cooling medium. For example, the intermediate support has cooling channels through which the cooling medium flows during operation of the semiconductor laser. However, the cooling channels can also be formed within a heat sink that is in thermal contact with the intermediate support. Thus, the heat sink, through which the cooling medium flows, cools the semiconductor body via the intermediate support during operation of the semiconductor laser.

[0057] For example, the semiconductor laser with the intermediate support directly below the semiconductor body is free of cooling channels. This allows the thickness of the intermediate support below the semiconductor body to be reduced.

[0058] According to at least one embodiment of the semiconductor laser, the semiconductor body is arranged in a top view of the semiconductor laser without overlap with the cooling medium, in particular such that the intermediate support has a lower temperature on a side facing away from a radiation-emitting side of the semiconductor body during operation of the semiconductor laser than on a side of the semiconductor body facing the radiation-emitting side. Cooling by means of the cooling medium is thus specifically designed so that a temperature gradient is established in the intermediate support during operation of the semiconductor laser. For example, the semiconductor laser is free of the cooling medium below the semiconductor body. 2024PF00462 August 29, 2025

[0059] P2024 , 0542 WO N

[0060] - 10 -

[0061] According to at least one embodiment of the semiconductor laser, the optical interaction structure features a lattice for distributed feedback of the semiconductor laser's radiation. Such semiconductor lasers are also referred to as DFB (Distributed Feedback) lasers. In a DFB laser, the optical interaction structure and the active region of the semiconductor laser can overlap in a top view. Here, a top view refers to a view of the semiconductor laser in a direction perpendicular to a principal plane of extension of the active region of the semiconductor body.

[0062] According to at least one embodiment of the semiconductor laser, the optical interaction structure features a lattice for a distributed Bragg reflector. Such semiconductor lasers are also referred to as DBR (Distributed Bragg Reflector) lasers. In a DBR laser, the optical interaction structure, viewed from above, is arranged in a way that is free of overlap with the active region.

[0063] According to at least one embodiment of the semiconductor laser, the optical interaction structure has a deflection structure that deflects radiation propagating along the active region in a direction oblique or perpendicular to it. The deflection structure can, in particular, function as an out-coupling structure for the radiation propagating in the resonator. The deflection structure can also be configured as a photonic crystal, for example, in the form of a one-dimensional or two-dimensional lattice or a three-dimensional photonic structure. Such 2024PF00462 29 August 2025 P2024 , 0542 WO N

[0064] 11

[0065] Semiconductor lasers are also known as PCSELs (Photonic Crystal Surface Emitting Lasers).

[0066] According to at least one embodiment of the semiconductor laser, it is a vertical cavity surface-emitting semiconductor laser. Such semiconductor lasers are also called VCSELs (Vertical Cavity Surface Emitting Lasers). In these semiconductor lasers, the propagation direction of the radiation oscillating in the resonator is perpendicular to the principal plane of extension of the active region.

[0067] The described design of the optical interaction structure for reducing differences in optical path lengths due to local temperature differences during operation of the semiconductor laser is fundamentally applicable to all types of semiconductor lasers with an optical interaction structure.

[0068] Furthermore, a method for manufacturing a semiconductor laser is described. This method is particularly suitable for manufacturing the semiconductor laser described above. Features described in connection with the semiconductor laser can therefore also be applied to the method, and vice versa.

[0069] According to at least one embodiment of the method, the method comprises the step of specifying a structural setup of the semiconductor laser with a semiconductor body having an active region, wherein the semiconductor body is arranged on an intermediate support. The semiconductor laser can be an edge-emitting semiconductor laser. 2024PF00462 29 August 2025

[0070] P2024 , 0542 WO N

[0071] - 12 - or specified as a surface-emitting semiconductor laser.

[0072] According to at least one embodiment of the method, the procedure comprises a step in which an expected spatial temperature profile in the semiconductor laser is determined at a predetermined operating point. In particular, the temperature profile is also determined in the region of the optical interaction structure of the semiconductor laser. The temperature profile in the semiconductor laser is influenced not only by the structure of the semiconductor body itself, but also by the type of mounting on the intermediate support, the type and geometric structure of the intermediate support, and the method of cooling the intermediate support.

[0073] According to at least one embodiment of the method, the method comprises a step in which an optical interaction structure with structural elements for the semiconductor laser is determined, wherein at least some of the structural elements are arranged at different nominal center distances to each other based on the expected spatial temperature profile.

[0074] The nominal center distances used for the subsequent fabrication of the optical interaction structure of the semiconductor laser are therefore specifically locally adapted based on the expected spatial temperature profile at the operating point.

[0075] The nominal center distance d* is derived from the relationship d* = d(T) - Zl d(T), 2024PF00462 29 . August 2025 P2024 , 0542 WO N

[0076] 13 where d(T) is the temperature-dependent center distance and 4d(T) is the temperature-dependent change in center distance.

[0077] The following applies: where do is the center distance for operation without heating, n0 is the refractive index without heating, and n(T) is the temperature-dependent refractive index in the region of the optical interaction structure.

[0078] For the temperature-dependent change in the center distance over a period P along a propagation direction x of the radiation, the following applies:

[0079] For the temperature-dependent refractive index n(T) averaged over a layer L, the following applies:

[0080] Thus, the nominal center-to-center spacing d* for the structural elements j can be selected based on the locally expected temperature at the operating point during the fabrication of the semiconductor laser such that the same optical path length results for the center-to-center spacings of the structural elements despite the temperature differences occurring during operation, or at least the optical path lengths approximate each other. 2024PF00462 29 August 2025

[0081] P2024 , 0542 WO N

[0082] 14

[0083] According to at least one embodiment of the method, the process comprises a step in which the semiconductor laser with the determined optical interaction structure is fabricated. The fabrication includes, for example, epitaxial deposition of the semiconductor layers of the semiconductor laser body, structuring the semiconductor layers into the semiconductor body, for example by lithographic methods, and optionally, mounting the semiconductor body onto the intermediate support.

[0084] In at least one embodiment of the method, the process comprises the following steps. A structural setup of the semiconductor laser with a semiconductor body containing an active region is specified, wherein the semiconductor body is arranged on an intermediate support. An expected spatial temperature profile in the semiconductor body is determined at a specified operating point. An optical interaction structure with structural elements is determined for the semiconductor laser, in which at least some of the structural elements are arranged at different nominal center distances to one another based on the expected spatial temperature profile. The semiconductor laser is fabricated with the determined optical interaction structure.

[0085] Even before the semiconductor laser is manufactured, the optical interaction structure is specifically adjusted so that, when temperature differences occur within the semiconductor laser, the optical path lengths associated with the center distances at least approximate each other. This allows for the selection of configurations for the structural design of the semiconductor laser. 2024PF00462 29 August 2025

[0086] P2024 , 0542 WO N

[0087] 15 will be, which are not ideal for uniform spatial heat dissipation from the semiconductor body, but are advantageous for other reasons, for example with regard to a compact design of the semiconductor laser and / or with regard to low manufacturing costs .

[0088] According to at least one embodiment of the method, the structural elements are arranged at different nominal center distances to each other based on the expected spatial temperature profile, such that local temperature differences of the expected temperature profile in the semiconductor laser reduce differences between the optical path lengths assigned to the nominal center distances of these structural elements when the semiconductor laser is operated at the specified operating point.

[0089] According to at least one implementation of the method, the optical path lengths at the operating point are determined based on the temperature dependence of at least one refractive index and the temperature dependence of the thermal expansion of material in the region of the optical interaction structure. For many common semiconductor materials, the temperature dependence of the lattice constant and the refractive index is known in the literature. If necessary, these parameters can be determined experimentally.

[0090] According to at least one implementation of the method, the nominal center-to-center distances of the structural elements are determined based on a stress state of the semiconductor body. Thus, when determining the nominal center-to-center distances, it can be taken into account, for example, whether the 2024PF00462 29. August 2025 P2024 , 0542 WO N

[0091] 16

[0092] Semiconductor material is fully or partially strained, pseudomorphic, or fully or partially relaxed.

[0093] The described manufacturing process allows the semiconductor laser to be produced in such a way that the non-periodic optical interaction structure takes into account the quasi-adiabatic temperature difference that builds up during laser operation. This improves the efficiency of the optical interaction structure and also the efficiency of the entire component. Furthermore, longer lifetimes can be achieved at lower operating currents.

[0094] The features described above, which are described, for example, in connection with at least one implementation form, can be combined with other features, which are described, for example, in connection with another implementation form, as long as these features do not exclude each other.

[0095] Further designs and advantages will become apparent from the following description of the exemplary designs in conjunction with the figures.

[0096] They show:

[0097] Figures 1A and 1B show an exemplary embodiment of a semiconductor laser in schematic sectional view (Figure 1A) and schematic top view (Figure 1B);

[0098] Figures IC and ID show an exemplary embodiment of a semiconductor laser in schematic sectional view (Figure IC) and schematic top view (Figure ID); 2024PF00462 29 August 2025

[0099] P2024 , 0542 WO N

[0100] - 17 -

[0101] Figure 2A shows an exemplary design of a semiconductor body for a semiconductor laser in perspective view;

[0102] Figure 2B shows a schematic representation of an example of optical path lengths of the optical interaction structure during operation of the semiconductor laser;

[0103] Figure 3 shows an exemplary embodiment of a semiconductor body in perspective view;

[0104] Figure 4 shows an exemplary embodiment of a semiconductor body in a schematic sectional view;

[0105] Figure 5 shows an exemplary embodiment of a semiconductor laser in a schematic sectional view; and

[0106] Figure 6 shows an exemplary embodiment of a method for manufacturing a semiconductor laser.

[0107] Identical, similar, or similarly effective elements are provided with the same reference symbols in the figures.

[0108] The figures are schematic representations and therefore not necessarily to scale. Rather, comparatively small elements and especially layer thicknesses may be exaggerated for easier illustration and / or better understanding.

[0109] In the exemplary embodiment of a semiconductor laser 1 shown in Figures 1A and 1B, the semiconductor laser 1 has a semiconductor body 2 with an active region 20 for generating radiation 8 and an optical interaction structure 3 with structural elements 30. 2024PF00462 29 August 2025 P2024 , 0542 WO N

[0110] 18

[0111] Details of the semiconductor body 2 are not explicitly shown in Figures 1A and 1B and are described in more detail with reference to Figures 2 to 4, which illustrate examples of suitable semiconductor bodies.

[0112] In the embodiment shown in Figure 2A, the semiconductor body 2 is designed as an edge-emitting semiconductor laser. During operation of the semiconductor laser 1, a front face 11 forms a radiation-emitting side 10 of the semiconductor laser 1. On a rear face 15 opposite the front face 11, the semiconductor body 2 is provided, for example, with a highly reflective coating. This is not explicitly shown in Figure 2A for the sake of simplicity.

[0113] The semiconductor body 2 has an active region 20 for generating radiation 8, which is arranged between a first semiconductor layer 21 of a first conduction type and a second semiconductor layer 2 of a second conduction type different from the first. For example, the first semiconductor layer 21 is p-type and the second semiconductor layer 22 is n-type, or vice versa.

[0114] The active region 20, the first semiconductor layer 21, and the second semiconductor layer 22 can each be multilayered. This is not explicitly shown for the sake of simplicity.

[0115] During operation of the semiconductor laser, radiation 8 propagates along a propagation direction 81 in a waveguide 4 in a lateral direction, i.e. along a plane parallel to a principal extension plane of the active region 20. 2024PF00462 29. August 2025

[0116] P2024 , 0542 WO N

[0117] - 19 -

[0118] Direction . Here, the radiation 8 oscillates in a lateral direction in a resonator 25 between the front 11 and the back 15 of the semiconductor body 2 .

[0119] The semiconductor laser 1 further comprises an optical interaction structure 3 with a plurality of structural elements 30. As schematically shown in Figure 2A, the structural elements 30 are arranged at different nominal center distances 35 from one another. In the example shown, the center distances 35 between adjacent structural elements 30 decrease towards the front face 11, which forms the radiation exit face 10 of the semiconductor laser 1.

[0120] The differences between the nominal center distances 35 are greatly exaggerated in Figure 2A. The nominal center distances 35 are chosen such that, during operation of the semiconductor laser 1 at a given operating point, local temperature differences in the optical interaction structure 3 reduce the differences between the optical path lengths assigned to the nominal center distances 35 of the structure elements 30.

[0121] Figure 2B schematically illustrates the optical path lengths 39, which are assigned to the respective center distances 35 of Figure 2A.

[0122] If a temperature gradient 9 develops at the operating point of the semiconductor laser 1, with the temperature increasing towards the radiation exit side 10, these temperature differences can cause the same optical path length 39 between adjacent structural elements 30 of the optical 2024PF00462 along the propagation direction 81. (August 29, 2025)

[0123] P2024 , 0542 WO N

[0124] - 20 -

[0125] Adjust the interaction structure 3. At the operating point, the semiconductor laser 1 therefore exhibits a periodic optical interaction structure 3 with respect to the optical path lengths.

[0126] In contrast, temperature differences in an optical interaction structure with periodically arranged structural elements would lead to it being detuned at least locally during operation of the semiconductor laser 1 due to the locally different thermal expansion and the change in the refractive index of the material in the area of ​​the optical interaction structure 3, and thus could only interact with the radiation 8 with reduced efficiency.

[0127] In the exemplary embodiment shown in Figure 2A, the optical interaction structure 3 forms a grid for distributed feedback of a DFB semiconductor laser. However, the described adjustment of the nominal center distances of structural elements 30 of an optical interaction structure 3 can also be applied to other types of semiconductor lasers.

[0128] For example, Figure 3 shows an embodiment of a semiconductor body 2 in which the semiconductor laser 1 is configured as a DBR semiconductor laser. In this example, the optical interaction structure 3 forms a distributed Bragg reflector for the radiation 8 propagating in the waveguide 4. In a top view of the semiconductor body 2, the active region 20 extends without overlap with the optical interaction structure 3. 2024PF00462 29 August 2025

[0129] P2024 , 0542 WO N

[0130] 21

[0131] The adaptation of the optical interaction structure 3 with respect to the nominal center distances 35 of the structural elements 30 can be carried out as described in connection with Figure 2A and 2B.

[0132] In the embodiment shown in Figure 4, the semiconductor laser 1 is designed as a surface-emitting semiconductor laser. In the embodiment shown in Figure 4, the radiation oscillates laterally between the front 11 and the back 15 of the semiconductor body 2, as in the preceding embodiments. The optical interaction structure 3 is designed as a deflecting structure that couples out propagating radiation along the active region 20, so that the radiation 8 exits through the surface of the semiconductor body 2. The radiation exit surface 10 thus runs parallel to the principal plane of extension of the active region 20.

[0133] In contrast to the representation shown, the optical interaction structure 3 can also be part of a surface-emitting semiconductor laser 1 with a vertical cavity. For example, the optical interaction structure 3 can be formed by a sequence of layers with layers of different refractive indices, by a one-dimensional or two-dimensional diffraction grating, or by a three-dimensional photonic crystal.

[0134] The nominal center distances 35 of the optical interaction structure 3 can each be chosen such that the 2024PF00462 occurring in the area of ​​the optical interaction structure 3 during operation of the semiconductor laser 1 29. August 2025

[0135] P2024 , 0542 WO N

[0136] - 22 -

[0137] Temperature fluctuations and the associated differences in thermal expansion and refractive index are at least partially compensated by the different nominal center distances 35.

[0138] In the setup of the semiconductor laser 1 shown in Figure 1A, the semiconductor body 2 is arranged on an intermediate support 5. The intermediate support 5 is designed to be actively cooled during operation of the semiconductor laser 1 by means of a cooling medium, for example a cooling liquid such as water.

[0139] For example, the intermediate support 5 has a coolant supply 51 and a coolant outlet 52, which are connected to each other via at least one cooling channel, for example in the form of a micro-cooling channel. Viewed from above, the intermediate support 5 interacts thermally with the coolant only in a region of the intermediate support 5 that does not overlap with the semiconductor body 2, for example behind the rear face 15 of the semiconductor body 2. This causes a temperature gradient 9 in the intermediate support 5 and thus also in the semiconductor body 2, with the temperature increasing towards the front face 11 of the semiconductor laser 1. In the region immediately below the semiconductor body 2, the intermediate support 5 can be free of cooling channels. This allows for a particularly compact design of the semiconductor laser 1. Furthermore, the semiconductor laser 1 can be characterized by low manufacturing costs.

[0140] As illustrated in Figures IC and ID, the cooling medium for cooling the intermediate support 5 can also run outside the intermediate support 5. For example, 2024PF00462 29 August 2025 P2024 , 0542 WO N

[0141] 23

[0142] Cooling channels 56 are formed in a heat sink 55, which is in thermal contact with the intermediate support 5. The intermediate support 5 itself therefore has no cooling channels. The heat sink 55, through which the cooling medium 59 flows, cools the semiconductor body 2 via the intermediate support 5 during operation of the semiconductor laser 1, whereby the temperature gradient 9 can be established in the intermediate support 5 as described above. Even with this cooling configuration, the cooling medium 59 can be free of overlap with the semiconductor body 2 when viewed from above.

[0143] The further explanations relating to Figures 1A and 1B apply analogously to the embodiment shown in Figures IC and ID. Both the cooling design according to Figures 1A and 1B and the design according to Figures IC and ID can be applied in all further embodiments.

[0144] With the described optical interaction structure 3 with specifically adapted nominal center distances 35, semiconductor lasers 1 with an efficient optical interaction structure 3 can be achieved, even if temperature differences occur during operation of the semiconductor laser 1 due to the structure and / or the type of mounting of the semiconductor body 2.

[0145] In the embodiment shown in Figure 1A, the semiconductor body 2 is electrically connected to a first contact 71 via connecting lines 61. A surface of the intermediate carrier 5, for example a rear side of the intermediate carrier 5 facing away from the semiconductor body 2, can have a second contact 72 for external electrical connection. 2024PF00462 29. August 2025 P2024 , 0542 WO N

[0146] 24

[0147] The semiconductor laser is contacted. In the illustrated embodiment, the first contact 71 is electrically insulated from the intermediate carrier 5 by an insulating layer 75, for example, an oxide layer. A suitable intermediate carrier 5 is, for example, a metal body, such as one containing or made of copper. The semiconductor laser 1 can be externally electrically contacted via the first contact 71 and the second contact 72.

[0148] Alternatively, a ceramic can also be used for the intermediate carrier 5, if necessary with an electrically conductive coating for electrical contacting the semiconductor body 2 .

[0149] The embodiment of a semiconductor laser shown in Figure 5 corresponds essentially to the embodiment described in connection with Figures 1A and 1B. The semiconductor body 2 can, in particular, be configured as described in connection with Figures 2 to 4.

[0150] In contrast to the embodiment described in Figures 1A and 1B, the semiconductor body 2 of the semiconductor laser 1 is electrically connected to the first contact 71 via a bonding layer 62. This reduces the height of the semiconductor laser, i.e., the extent of the semiconductor laser 1 perpendicular to the principal plane of extension of the semiconductor body 2.

[0151] As shown in Figure 5, the intermediate carrier 5 can have a reduced thickness in the region of the semiconductor body 2. This allows the height of the assembly to be further reduced. Furthermore, the thickness of the 2024PF00462 29. August 2025 P2024 , 0542 WO N

[0152] 25

[0153] The intermediate carrier 5 is chosen such that a top surface of the semiconductor body 2 facing away from the intermediate carrier 5 is at least approximately at the level of the insulation layer 75, so that the interconnection layer 62 overcomes no or at least only a small height difference at a transition between the intermediate carrier 5 and the semiconductor body 2.

[0154] Figure 6 schematically illustrates an exemplary embodiment of a method for manufacturing a semiconductor laser. For improved understanding, the reference symbols for the structural elements shown in Figures 1 to 5 are used in the following description of Figure 6, even though these are not explicitly shown in Figure 6 for the sake of simplicity.

[0155] In step S 1, a structural setup of the semiconductor laser 1 with a semiconductor body 2 with an active region 20 is specified, wherein the semiconductor body is arranged on an intermediate support.

[0156] In step S2, an expected spatial temperature profile in the semiconductor laser, particularly in the region of the optical interaction structure 3 described above, is determined at a specified operating point. For this purpose, simulations are performed, for example, to determine the spatial temperature distribution within the semiconductor body 2 at the specified operating point.

[0157] In step S3, an optical interaction structure with structural elements 30 for the semiconductor laser 1 is constructed, wherein all or at least some of the 2024PF00462 29. August 2025

[0158] P2024 , 0542 WO N

[0159] 26

[0160] Structural elements 30 are arranged at different nominal center distances 35 based on the expected spatial temperature profile. The center distances 35 are thus determined with knowledge of the expected temperature profile in the semiconductor laser 1.

[0161] In step S4, the semiconductor laser 1 with the determined optical interaction structure 3 is fabricated. In this way, a semiconductor laser can be fabricated in which the structural elements 30 are arranged at different nominal center distances 35 such that local temperature differences of the expected temperature profile in the semiconductor laser 1 during operation of the semiconductor laser at the specified operating point reduce differences between the optical path lengths 39, which are assigned to the nominal center distances 35 of the structural elements 30.

[0162] In particular, the optical path lengths at the operating point can be determined based on the temperature dependence of the refractive index in the region of the optical interaction structure and the thermal expansion in the region of the optical interaction structure.

[0163] Furthermore, when determining the nominal center distances 35 of the structural elements 30, the strain state of the semiconductor body 2 can also be taken into account.

[0164] The described method can generally be used to manufacture semiconductor lasers in which an optical interaction structure is specifically adapted to expected temperature differences during the operation of the semiconductor laser. 2024PF00462 August 29, 2025 P2024, 0542 WO N

[0165] - 27 - is adapted so that overall higher efficiency can result for the semiconductor laser.

[0166] This patent application claims priority over German patent application 10 2024 125 049.6, the disclosure content of which is hereby incorporated by reference.

[0167] The invention is not limited by the description based on the exemplary embodiments. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or combination itself is not explicitly specified in the patent claims or the exemplary embodiments.

[0168] 2024PF00462 29 . August 2025 P2024 , 0542 WO N

[0169] 28

[0170] Reference character list

[0171] 1 semiconductor laser

[0172] 10 Radiation exit side

[0173] 11 Front

[0174] 15 Back

[0175] 2 Semiconductor bodies

[0176] 20 active area

[0177] 21 first semiconductor layer

[0178] 22 second semiconductor layer

[0179] 25 Resonator

[0180] 3 optical interaction structure

[0181] 30 structural element

[0182] 35 nominal center-to-center distance

[0183] 39 optical path length

[0184] 4 waveguides

[0185] 5 intermediate beams

[0186] 51 Coolant supply

[0187] 52 Coolant drainage

[0188] 55 heat sinks

[0189] 56 Cooling channel

[0190] 59 Cooling medium

[0191] 61 Connecting line

[0192] 62 Compound layer

[0193] 71 first contact

[0194] 72 second contact

[0195] 75 I insulation layer

[0196] 8 Radiation

[0197] 81 Direction of propagation

[0198] 9 Temperature gradient

[0199] SI, S2, S3, S4 step

Claims

2024PF00462 August 29, 2025 P2024, 0542 WO N - 29 - Patent claims 1. Semiconductor laser (1) comprising a semiconductor body (2) with an active region (20) for generating radiation (8) and an optical interaction structure (3) with structural elements (30) , wherein at least some of the structural elements (30) are arranged at different nominal center distances (35) to each other such that, during operation of the semiconductor laser (1) at a given operating point, local temperature differences in the optical interaction structure (3) reduce differences between the optical path lengths (39) , which are assigned to the nominal center distances (35) of these structural elements (30).

2. Semiconductor laser according to claim 1, wherein a relative difference between the optical path lengths (39) at the operating point is smaller, at least for some of the structural elements (30), than a relative difference between the corresponding associated nominal center distances (35).

3. Semiconductor laser according to claim 1 or 2, wherein the interaction structure (3) in the operation of the semiconductor laser (1) has a temperature gradient (9) along a propagation direction (81) of the radiation in a resonator (25) of the semiconductor laser (1).

4. Semiconductor laser according to one of the preceding claims, wherein the semiconductor body (2) is arranged on an intermediate support (5).

5. Semiconductor laser according to claim 4, 2024PF00462 August 29, 2025 P2024, 0542 WO N 30 wherein the intermediate carrier (5) on a side facing away from a radiation exit side (10) of the semiconductor body has a lower temperature during operation of the semiconductor laser than on a side of the semiconductor body facing the radiation exit side .

6. Semiconductor laser according to claim 4 or 5, wherein the intermediate carrier (5) is provided for cooling by a cooling medium.

7. Semiconductor laser according to claim 4, wherein the intermediate carrier (5) is provided for cooling by a cooling medium (59), wherein the semiconductor body (2) is arranged in a top view of the semiconductor laser without overlapping with the cooling medium (59), so that the intermediate carrier (5) has a lower temperature on a side facing away from a radiation output side (10) of the semiconductor body (2) during operation of the semiconductor laser (1) than on a side of the semiconductor body (2) facing the radiation output side (10).

8. Semiconductor laser according to one of the preceding claims, wherein the optical interaction structure (3) comprises a grid for distributed feedback of the radiation of the semiconductor laser.

9. Semiconductor laser according to one of the preceding claims, wherein the optical interaction structure comprises a grating (3) for a distributed Bragg reflector.

10. Semiconductor laser according to any of the preceding claims, wherein the optical interaction structure (3) is a 2024PF00462 August 29, 2025 P2024, 0542 WO N 31 It features a deflection structure that runs along the active area. (20) deflects propagating radiation in a direction oblique or perpendicular to it.

11. Semiconductor laser according to any of the preceding claims wherein the semiconductor laser (1) is a surface-emitting semiconductor laser with a vertical cavity.

12. Method for fabricating a semiconductor laser comprising the steps of: a) specifying a structural setup of the semiconductor laser (1) with a semiconductor body (2) having an active region (20), wherein the semiconductor body (2) is arranged on an intermediate support (5); b) determining an expected spatial temperature profile in the semiconductor laser (1) at a specified operating point; c) determining an optical interaction structure (3) with structural elements (30) for the semiconductor laser (1), wherein at least some of the structural elements (30) are arranged at different nominal center distances (35) to each other based on the expected spatial temperature profile; and d) fabricating the semiconductor laser (1) with the determined optical interaction structure (3).

13. Method according to claim 12, wherein the structural elements (30) are arranged in step c) such that local temperature differences of the expected temperature profile in the semiconductor laser (1) during operation of the semiconductor laser (1) at the predetermined operating point result in differences between the optical path lengths 2024PF00462 August 29, 2025 P2024, 0542 WO N 32 (39) , which are assigned to the nominal center distances (35) of these structural elements (30), decrease.

14. Method according to claim 12 or 13, wherein the optical path lengths (39) at the operating point are determined based on a temperature dependence of at least one refractive index and based on a temperature dependence of a thermal expansion of material in the region of the optical interaction structure (3).

15. Method according to one of claims 12 to 14, wherein the nominal center distances (35) of the structural elements (30) are determined based on a strain state of the semiconductor body (2).

16. Method according to claim 14, by which a semiconductor laser (1) according to any one of claims 1 to 11 is manufactured.

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