Production method for semiconductor lasers, and semiconductor lasers

Abstract

In at least one embodiment, the method is used to produce semiconductor lasers (1) and comprises the steps: - providing a plurality of laser emitters (2), at least one facet (22) of each of the laser emitters (2) being exposed, - electrically or optically pumping the laser emitters (2) such that the laser emitters (2) emit laser radiation (L), - generating a coating (3) on the facets (22), a local layer thickness (t) of the coating (3) over the facets (22) being determined by a local intensity of the laser radiation (L).

Description

[0001] 2024PF00793 October 8, 2025

[0002] P2024, 0729 WO N

[0003] - 1 -

[0004] Description

[0005] MANUFACTURING PROCESS FOR SEMICONDUCTOR LASERS AND SEMICONDUCTOR LASERS

[0006] A manufacturing process for semiconductor lasers is described. Furthermore, a semiconductor laser manufactured according to this process is described.

[0007] The publication DS Larionov et al., “Stereolithographic Fabrication of Alumina Ceramics from Aluminum Chloride- Containing Polymerizable Precursors” in Inorg Mater 59, pages 210 to 220 from 2023, https: / / doi.org / 10.1134 / S0020168523020103, concerns the photochemical provision of aluminum.

[0008] The publication by O. Aalling-Frederiksen et al., “Formation and growth mechanism for niobium oxide nanoparticles: atomistic insight from in situ X-ray total scattering” in Nanoscale, Volume 2021, Issue 13, pages 8087 to 8097, https: / / doi.org / 10.1039 / D0NR08299F, concerns the photochemical provision of niobium.

[0009] One task to be solved is to specify a semiconductor laser that can be manufactured efficiently.

[0010] This problem is solved, among other things, by a method and by a semiconductor laser with the features of the independent patent claims. Preferred embodiments are the subject of the dependent claims.

[0011] According to at least one embodiment, the process is used to manufacture semiconductor lasers. Semiconductor lasers preferentially convert electrical current into radiation, thus operating according to 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0012] 2. by means of electroluminescence. In particular, the semiconductor lasers each comprise a sequence of semiconductor layers. The sequence of semiconductor layers includes at least one active zone, which is configured to generate the radiation. The active zone includes, for example, at least one pn junction and / or at least one quantization structure, such as a quantum well structure. A wavelength of maximum intensity of the radiation generated by the active zone during operation is, in particular, at least 290 nm and at most 1100 nm, for example, at least 290 nm and at most 530 nm or at least 360 nm and at most 465 nm.

[0013] The semiconductor layer sequence is preferably based on a II-I-V compound semiconductor material. This semiconductor material is, for example, a nitride compound semiconductor material such as Al. n In]__ n-m Ga m N or a phosphide compound semiconductor material such as Aln In]__ n-m Ga m P or also an arsenide compound semiconductor material such as Al n In]__ n-m Ga m As or like Alj^Gaj^In^. -j^AspP^-p, where j is 0 < n < 1, 0 < m < 1, n + m < 1, and 0 < k < 1. For example, for at least one layer or for all layers of the semiconductor layer sequence, 0 < n < 0.8, 0.4 < m < 1, n + m < 0.95, and 0 < k < 0.5 hold true. The semiconductor layer sequence may contain dopants and additional components. For the sake of simplicity, however, only the essential components of the crystal lattice of the semiconductor layer sequence, i.e., Al, As, Ga, In, N, or P, are given, even though these may be partially replaced and / or supplemented by small amounts of other substances.

[0014] According to at least one implementation form, the method comprises the step of providing a laser emitter or a 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0015] 3

[0016] Multiple laser emitters. These laser emitters include, for example, edge-emitting lasers. However, the method can also be applied to surface-emitting lasers, also known as vertical cavity surface-emitting lasers or VCSELs for short. For example, these laser emitters are gain-guided or have a waveguide structure, such as a web waveguide.

[0017] Furthermore, it is possible to apply the process to light-emitting diodes (LEDs) or other electro-optical components instead of laser emitters. Thus, the process can be used to manufacture optoelectronic semiconductor components by coating facets of optoelectronic semiconductor bodies. The following explanations apply accordingly to such a process.

[0018] According to at least one embodiment, one or two facets of some or each of the laser emitters are exposed. This means that the relevant facets are freely accessible, particularly to a gas in a reaction chamber, such as a chemical or physical vapor deposition (CVD) or physical vapor deposition (PVD) system. It is possible that the upper surface and / or side surfaces of the laser emitters facing away from a substrate, which connect opposing facets, are also exposed. This means that the laser emitters may be free of masking layers. The facets are produced, for example, by etching or fracturing.

[0019] According to at least one embodiment, the method includes the step of electrically and / or optically pumping the laser emitters. This causes the laser emitters to emit laser radiation. In other words, the laser emitters can 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0020] 4. The laser radiation emitted in this step can correspond, with respect to spatial and / or spectral distribution, to radiation later generated in the operation of the finished semiconductor lasers.

[0021] According to at least one embodiment, the method comprises the step of generating a coating on the exposed facets. This process step is carried out, in particular, partially or completely simultaneously with the step of electrically and / or optically pumping the laser emitters.

[0022] According to at least one implementation, the local thickness of the coating across the facets is determined by the locally present intensity of the laser radiation. That is, there can be a mathematical function between the locally present intensity as input value and the local layer thickness as output value. The higher the locally present intensity, the greater the local layer thickness.

[0023] The locally present intensity can change during the coating process; that is, the locally present intensity can vary over time. For example, the locally present intensity decreases during the coating process. In other words, the resulting local coating thickness can be a function of the integral of the locally present intensity over the duration of the coating process. The resulting local coating thickness can depend, for example, linearly, quadratically, or cubically on the locally present intensity of the laser radiation. 2024PF00793 October 8, 2025

[0024] P2024 , 0729 WO N

[0025] In at least one embodiment, the process is used to manufacture semiconductor lasers and comprises the following steps:

[0026] - Providing a plurality of laser emitters, with at least one facet of each laser emitter exposed,

[0027] - electrical or optical pumping of the laser emitters so that the laser emitters emit laser radiation,

[0028] - Generating a coating on the facets, wherein a local layer thickness of the coating across the facets is determined by a locally present intensity of the laser radiation.

[0029] Thus, for example, a laser diode with local faceted coating can be produced.

[0030] The manufactured optoelectronic semiconductor components, such as semiconductor lasers, can be used, for example, in the application fields of augmented reality, virtual reality, displays, projection, 3D printing and / or leveling.

[0031] Optoelectronic semiconductor components with locally individualized layer properties, such as a mirror coating (e.g., geometric features, especially thickness), and / or material composition, position, refractive index, reflectivity, and / or absorption, can be achieved. Thus, locally individualized layer properties are attainable at the facets.

[0032] In a conventional coating of surfaces or laser facets in a batch process, all adjacent components, for example within a

[0033] Laser bars or multi-emitters, same properties as 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0034] 6

[0035] Mirror coating. In contrast, the method described here uses a photochemical coating process, which enables local and / or individual coating customization on a surface or facet of an electro-optical semiconductor component.

[0036] In the proposed photochemical coating process, the components to be coated are electrically operated during the coating process, for example, to selectively emit light and, depending on the light intensity, to influence the deposition of layers at the light-emitting area on the component. In this way, even in a batch process, individual layer thicknesses, material compositions, and / or positioning of the respective coating can be achieved by individually controlling the components during coating.

[0037] This means that, despite the batch process, individual layer thickness, composition, and / or positioning is possible for neighboring emitters on a chip or ingot by actively operating the components to be coated with appropriate precursors during the photochemical coating process. Local light emission makes it possible to selectively influence the deposition of layers at the relevant light-emitting location on the component.

[0038] One advantage of this process lies in the possibility of achieving locally different and individual coatings and / or mirror finishes, and thus individual characteristics of the emitters. This is particularly interesting for multi-emitter components, i.e., chips with 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0039] 7 multiple emitters with small distances between the emitters.

[0040] According to at least one implementation form, the production of the coating includes:

[0041] - Providing one or more precursor gases for a coating material or for several coating materials of the coating at the facets,

[0042] - Decomposition of at least one precursor gas by the laser radiation, and

[0043] - Deposition of at least one coating material on the facets.

[0044] In other words, the laser radiation generates at least one coating material through photochemistry. This occurs, in particular, directly at the relevant facets, depending on the intensity of the laser radiation. It is possible that the decomposition of the at least one precursor gas is limited to an area close to the facets and / or that the at least one coating material forms, depending on the intensity, only where the laser radiation exits the relevant facet.

[0045] In the case of multiple precursor gases, it is possible to supply them in pulsed or sequential mode. This makes it possible to assemble the coating from several sublayers made of different coating materials. For example, exactly two coating materials, and therefore exactly two precursor gases, are used, so that the relevant sublayers are produced in alternating succession. 2024PF00793 October 8, 2025 P2024, 0729 WO N

[0046] 8

[0047] According to at least one embodiment, the precursor gas comprises one or more substances from the following group, or the precursor gas consists of one or more of these substances:

[0048] - tetraethyl orthosilicate, TEOS,

[0049] - Trimethylgallium, TMGa,

[0050] - p-Phenylene diisothiocyanate, DITC, and its derivatives,

[0051] - Tert-butylimido tris-diethylamido tantalum, Ta (N^Bu) (NEtgJ g, TBTDET,

[0052] - Ta (Ntßu) (NEt2) 2 C P< TBDETCp,

[0053] - Tetrakis (dimethylamino) hafnium, TDMAH,

[0054] - Tetrakis (ethylmethylamino) hafnium, TEMAHf,

[0055] - Niobeth oxide, N₂OCgHgJ g,

[0056] - aluminum acrylate, Al (OH) 2 (OOC-CH=CH2),

[0057] - Organoalumoxane aluminum.

[0058] Information on the photochemical provision of materials can also be found in the above-cited publications by DS Larionov et al. and O. Aalling-Frederiksen et al., whose disclosure content regarding photochemical provision is included by reference.

[0059] In addition to the at least one precursor gas, oxygen can be supplied as a reactive gas. In particular, the decomposition of the at least one precursor gas can be caused by an interaction of oxygen and laser radiation.

[0060] According to at least one implementation form, the local layer thickness of the finished coating across the facets is proportional to the locally present intensity or proportional to a power of the locally present 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0061] 9

[0062] The intensity of the laser radiation generated during the deposition of the coating material is calculated. In other words, in a cross-section perpendicular to the facets, the resulting local layer thickness t(x) at a location x and the locally present intensity I(x) can be given by: t(x) = k I(x)b, where k is a constant greater than zero and b is a power coefficient f. For example, b = 1 or 1 < bd 4 or 1 < bd 2.5. If the intensity changes over time, then for a coating duration T, the following can be given by: t(x) = f t :0ki(x, t) b If not only a cross-section is considered, then t usually depends on two, in particular orthogonal, spatial coordinates x and y.

[0063] According to at least one implementation, the coating is only created at points on the facets where the locally present intensity of the laser radiation exceeds a threshold value greater than zero. Alternatively, there is no threshold value for the intensity of the laser radiation.

[0064] According to at least one embodiment, the coating is applied to a pre-coating. In other words, the pre-coating is located between the relevant facet and the relevant coating. The pre-coating can be applied directly to the facet, which, for example, consists of a semiconductor material from a semiconductor layer sequence, and the coating can be applied directly to the pre-coating.

[0065] According to at least one implementation form, the pre-coating is a passivation, a Bragg mirror, or a

[0066] Anti-reflective coating. The pre-coating can be applied according to 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0067] 10 be a single layer or a stack of layers consisting of several sub-layers, analogous to coating.

[0068] According to at least one embodiment, the pre-coating has a constant coating thickness. In other words, the thickness of the pre-coating remains constant across the facet, within the manufacturing tolerances. The pre-coating can therefore be free of intentional variations in layer thickness.

[0069] According to at least one embodiment, some or all of the laser emitters comprise one or more main emitter strips and one or more secondary emitter strips. Viewed from above, the secondary emitter strip is arranged next to the main emitter strip. It is possible that the at least one secondary emitter strip is operated only during coating production, while the main emitter strip is configured to generate and emit the laser radiation during the intended operation of the semiconductor laser. If several secondary emitter strips are present per main emitter strip, these secondary emitter strips can be operated simultaneously or sequentially during coating production.

[0070] According to at least one embodiment, the coating is applied only to one facet of the at least one secondary emitter strip. For example, this creates an aperture for the main emitter strip on the at least one secondary emitter strip. For example, in this case, two secondary emitter strips are provided per main emitter strip. The secondary emitter strips can block interfering lateral emissions from the main emitter strip, that is, such 2024PF00793 8 October 2025

[0071] P2024 , 0729 WO N disruptive emissions can be prevented from leaving the semiconductor laser.

[0072] According to at least one embodiment, the local layer thickness, particularly with respect to the finished coating on one or all laser emitters of a laser array, is varied across the facet(s) by at least 30% or at least 50% of the maximum coating thickness. This means that comparatively large thickness variations are generated.

[0073] According to at least one implementation, in electric or optical pumping, at least some of the laser emitters are operated simultaneously. This means that the coating can be applied to a large number of laser emitters at the same time, with locally varying coating thicknesses being possible.

[0074] According to at least one embodiment, the coating is produced using a non-directional coating process. This means that the coating can be produced independently of the relative orientations of the facets. The resulting layer thicknesses therefore depend only on the intensity of the laser radiation, and not on the orientations of the facets.

[0075] According to at least one implementation form, providing the majority of laser emitters includes:

[0076] - Providing an emitter array in which the laser emitters are arranged on a common support in a fixed position relative to each other.

[0077] For example, the common carrier is electrically conductive, so the carrier can be used as an electrical contact for the 2024PF00793 8 October 2025

[0078] P2024 , 0729 WO N

[0079] - 12 - can serve as a single laser emitter. It is possible that the common support is a growth substrate for the semiconductor layer sequence of the laser emitters. Optionally, several of the common supports with their associated laser emitters can undergo the coating process simultaneously.

[0080] According to at least one implementation form, the process after the coating has been produced additionally includes:

[0081] - Dividing the emitter array into emitter groups, each containing at least two of the laser emitters.

[0082] This means that the finished semiconductor lasers can comprise several laser emitters. The laser emitters of a semiconductor laser can have different coatings for different emission properties.

[0083] According to at least one implementation method, several of the coatings are applied to the laser emitter.

[0084] For example, different types of coatings can be applied, which differ in their material compositions. Which type of coating is applied to which laser emitter can be set by sequentially operating the laser emitters during the coating application process.

[0085] Furthermore, a semiconductor laser is specified. The semiconductor laser is manufactured using a method as described in connection with one or more of the aforementioned embodiments. Characteristics of the semiconductor laser are therefore also known for the method and vice versa. The semiconductor laser can generally be 2024PF00793 8 October 2025

[0086] P2024 , 0729 WO N - 13 - also refers to an optoelectronic semiconductor component with a semiconductor emitter.

[0087] In at least one embodiment, the semiconductor laser has a coating with varying local layer thickness at the facet.

[0088] According to at least one embodiment, the coating comprises one or more oxides, nitrides, and / or oxynitrides. The oxides, nitrides, or oxynitrides can have a stoichiometric composition for controlled material properties. However, for more efficient application, non-stoichiometric oxides, nitrides, or oxynitrides can also be used. For example, the coating may comprise one or more metal oxides or semiconductor oxides.

[0089] According to at least one embodiment, the coating comprises one or more of the following materials, or the coating consists of one or more of these materials: silicon oxide, aluminum oxide, tantalum oxide, hafnium oxide, niobium oxide.

[0090] The following section provides a more detailed explanation of a method and a semiconductor laser described herein, with reference to the drawing and illustrated examples. The same reference symbols indicate identical elements in the individual figures. However, the figures are not to scale; rather, individual elements may be exaggerated for clarity. 2024PF00793 October 8, 2025 P2024, 0729 WO N

[0091] 14

[0092] They show:

[0093] Figure 1 is a schematic block diagram of a

[0094] From an exemplary manufacturing process for optoelectronic semiconductor components, in particular semiconductor lasers, described here,

[0095] Figures 2 to 5 are schematic top views of process steps of an exemplary embodiment of a manufacturing process described here.

[0096] Figure 6 shows a schematic sectional view of a process step, an exemplary embodiment of a manufacturing process described here.

[0097] Figure 7 shows a schematic sectional view of a process step of a modification of a manufacturing process.

[0098] Figure 8 shows a schematic sectional view of a process step, an exemplary embodiment of a manufacturing process described here.

[0099] Figures 9 to 11 are schematic top views of process steps from exemplary manufacturing processes described here.

[0100] Figure 12 is a schematic sectional view of the process step of Figure 11, and

[0101] Figure 13 shows a schematic sectional view of an exemplary embodiment of a semiconductor laser described herein. 2024PF00793 8 October 2025

[0102] P2024 , 0729 WO N - 15 -

[0103] Figure 1 shows an example of a manufacturing process for optoelectronic semiconductor components, such as semiconductor laser 1, as a block diagram.

[0104] In a process step S 1, a plurality of optoelectronic semiconductor components, such as laser emitters 2, are provided. At least one facet 22 of each of these laser emitters 2 is exposed, see also Figure 2.

[0105] In process step S21, the laser emitters 2 are electrically or optically pumped so that they emit laser radiation L (see also Figure 3). Simultaneously, process step S22 is carried out, according to which a coating 3 is produced on the facets 22, the local thickness t of the coating 3 across the facets 22 being determined by a locally present intensity I of the laser radiation L (see also Figure 4).

[0106] In the optional process step S3, an emitter array 20, which may optionally include the laser emitters 2, is divided into several of the semiconductor lasers 1, see also Figure 5.

[0107] Electro-optical semiconductor devices, such as edge-emitting lasers 1, typically require a faceted coating 3, 42. This coating serves to adjust the desired properties of the devices 1 with respect to electro-optical parameters such as threshold current or transconductance. Furthermore, such a coating 3, 42 can be used to influence the wavelength or the emission characteristics in the far field of the device 1. A common feature of such faceted coatings 3, 42 is that, for cost reasons, a large number of devices 1 are often coated with a single faceted coating. (2024PF00793 8 October 2025 P2024 , 0729 WO N)

[0108] 16 stacked ingot form or in wafer composite, are coated simultaneously.

[0109] However, a typical batch process has significant limitations regarding the individual adaptation of the layers to a single component. Customizing the type of mirror coating, layer thickness, reflectivity, position, and shape of the layers on a facet individually for each component is fundamentally impossible in a conventional batch process.

[0110] The method described here enables individual coating customization on a surface or facet of an electro-optical semiconductor component, even when coating many components 1 in a batch process. This is achieved using a photochemical coating process with appropriate precursors, the deposition of which on the semiconductor material depends on light irradiation. In such a process, the components 1 to be coated are, for example, electrically driven during the coating process to selectively emit light and, depending on the light intensity, influence the deposition of layers at the light-emitting location on the component. Thus, even in a batch process, individual layer thicknesses, layer compositions, and / or layer positions can be achieved by individually controlling the components during coating production.

[0111] Figures 2 to 5 illustrate a more detailed example of the procedure. 2024PF00793 8 October 2025

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[0113] 17

[0114] In the step shown in Figure 2, for example, an emitter array 20 is provided with a variety of optoelectronic semiconductor components. According to Figures 2 to 5, the optoelectronic semiconductor components are, for example, edge-emitting laser emitters 2; however, the method can be applied equally to other types of components, such as LEDs or VCSELs.

[0115] The laser emitters 2 shown as examples can each have a waveguide 27 for guiding a laser beam. The waveguides 27 are formed, for example, from a sequence of semiconductor layers, such as by etching. The semiconductor layer sequence can be mounted on a common support 5, such as a growth substrate. The individual waveguides 27 can be arranged parallel to each other and be identical in construction within the manufacturing tolerances, i.e., designed, for example, for the same emission wavelength and / or the same maximum electrical power consumption. A distance between adjacent waveguides 27 is, for example, at least 10 pm or at least 20 pm and / or at most 200 pm or at most 80 pm. For example, the waveguides 27 have a width of at least 1 pm and / or at most 100 pm.

[0116] Optionally, the waveguides 27j are each covered by a top electrode 26, so that the waveguides 27 are located between the carrier 5 and the top electrode 26. The top electrodes 26 are configured for electrical contact with the laser emitters 2. 2024PF00793 8 October 2025 P2024, 0729 WO N

[0117] 18

[0118] Facets 22 of the laser emitter 2 are formed, for example, from a semiconductor material of the semiconductor layer sequence, in particular from Al InGaN. Optionally, pre-coatings 42A, 42B are applied directly to the facets. Pre-coating 42A is, for example, a partially reflective coating or an anti-reflective coating. Pre-coating 42B is, in particular, a highly reflective coating. The pre-coatings 42A, 42B can be Bragg layer sequences.

[0119] In the step shown in Figure 3, the emitter assembly 20 is introduced into a process chamber, which can be supplied with various precursors in a precursor gas 41. The individual laser emitters 2 are electrically contacted, for example, via the carrier 5 as the cathode and via the top electrodes 26 as the anodes. Thus, the individual laser emitters 2 can be energized independently of one another or in groups, so that laser radiation L is emitted at the facets 22 with the pre-coating 42A.

[0120] As an alternative to current supply, the laser emitters 2 can also be excited to generate the laser radiation L by means of photoluminescence, i.e. by optical pumping.

[0121] By operating the components, the precursor gas 41 is at least partially decomposed due to the emission of laser radiation L, which preferably has a wavelength of maximum intensity of at most 530 nm, and a coating material 30 is generated in the process chamber and deposited on the facets 22 or on the pre-coating 42A in the area of ​​the waveguide 27. Depending on the light power and / or duration of operation, individual laser emitters can thus be 2 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0122] 19 of the emitter array 20 can be individually coated, and in this way locally different coatings or mirror finishes, and thus characteristics of the finished components 1, can be achieved. This is particularly interesting for multi-emitter components with small distances between the individual laser emitters 2.

[0123] Exemplary finished coatings 3 made of coating material 30 are illustrated in Figure 4. The coatings 3 exhibit a local layer thickness t depending on a spatial coordinate x. Figure 4 shows only a sectional view, so there is usually a second spatial coordinate y perpendicular to the plane of Figure 4, along which the local layer thickness t varies. It is possible for the variation of the local layer thickness t to be up to 100% of the maximum layer thickness T of the coating 3.

[0124] In the example shown in Figure 4, every second laser emitter 2 is provided with a thicker coating 3. It is possible that the coatings 3 are composed of several sublayers, for example, of different materials. For instance, the thicker coatings 3 may have two such sublayers, whereas the thinner coatings 3 may optionally consist of only a single layer.

[0125] The coating 3 is produced, for example, in a high vacuum, such as at least room temperature (20°C), and / or at a temperature below 400°C, 150°C, or 100°C. Process parameters are similar to those used in laser-CVD (2024PF00793, October 8, 2025).

[0126] P2024 , 0729 WO N

[0127] - 20 - are used, with temperatures of, for example, a maximum of 150 °C being used.

[0128] In the optional step of Figure 5, the emitter array 20 is then divided into the individual semiconductor lasers 1. For example, the semiconductor lasers 1 each have more than one of the laser emitters 2, for example two of the laser emitters 2.

[0129] Furthermore, the statements relating to Figure 1 apply equally to Figures 2 to 5, and vice versa.

[0130] In contrast to the method shown in Figures 2 to 5, another possibility is that the coating 3 is applied only after the laser emitters 2 have been mounted in a housing (not shown). This means that the singulation can take place before the coating is applied. The same applies to all other examples of the method and the semiconductor component, such as the semiconductor laser 1.

[0131] Figure 6 shows a sectional view along the waveguide 27. As can be seen in Figure 6, several laser emitters 2 can optionally be arranged consecutively along a longitudinal direction of the waveguide 27. Thus, a two-dimensional arrangement of the laser emitters 2 can be seen in a top view of the support 5. This is also possible in all other examples.

[0132] Figure 6 also shows that a non-directional coating process is used, meaning that the precursors 41 do not move along a specific, predetermined direction. 2024PF00793 October 8, 2025

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[0134] The semiconductor layer sequence 21 of the laser emitters 2 each has an active zone 25, such as a quantum well structure. The laser emitters 2 are operated, for example, with different electrical currents II, 12, 13, in order to individually adjust the coating 3 for each laser emitter 2. It is possible for the coating material to be produced exclusively on the facets 22 or on the optional pre-coating 42. The facets 22 and the waveguides 27 as a whole are produced, for example, by etching.

[0135] Furthermore, the statements relating to Figures 1 to 5 apply equally to Figure 6, and vice versa.

[0136] Figure 7 shows a modification of the method described here. In this case, laser facets are mirrored on-wafer, for example, in laser emitters 2 with etched facets 22. Reliable thickness control is only possible with a directional coating, in Figure 7 from top to bottom. This involves reshaping the facets 22 vertically, i.e., in a direction parallel to the coating direction. The following three aspects are particularly problematic:

[0137] - The over-forming results in only a fraction of the thickness of the layers in the direction perpendicular to the coating direction, which increases the time and / or material required to produce the coating.

[0138] - The layers deposited on the top surface, such as the top surface electrodes 26, must be reopened or removed later in the process to electrically contact the semiconductor 1. This involves a photographic technique and an etching step, so more time is required. 2024PF00793 8 October 2025 P2024, 0729 WO N

[0139] 22 and the costs are rising.

[0140] - The mirror layers are typically rougher on the vertical side, i.e. on facet 22, than on the top side, which can lead to less precisely adjustable optical properties.

[0141] These problems can be circumvented using the method described here.

[0142] Figure 8 shows another example, where laser emitter 2 is a multimode emitter. The intensity I of the individual modes is shown schematically on the left side of Figure 8.

[0143] With laterally multimode lasers, mode dynamics can lead to intensity increases at facet 22 in certain locations, often at the edge. These are frequently areas where catastrophic optical mirror damage (COMD) can occur more frequently.

[0144] The method described here allows more coating material 30 to be deposited precisely at the points of intensity increase, thus achieving, depending on the design of the coating 3, a lower reflectivity, so that the modes at the edge suffer greater optical losses and are attenuated.

[0145] This is schematically illustrated in Figure 8, right side. Accordingly, the coating 3 has a first coating area 31 with a comparatively high reflectivity and, for example, a circumferential second coating area. 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0146] 23

[0147] Coating area 32 with a lower reflectivity for the laser radiation L on .

[0148] Figure 9 illustrates a corresponding situation in a sectional view. Here, the coating 3 has two edge-level thickness maxima. Additionally, a central local thickness maximum 3 is present, where the thickness is greater at the edges. Between the edge regions with the edge-level thickness maxima and a central region, thickness minima may optionally exist, where the thickness is, for example, less than 30% or less than 10% of the maximum thickness. The following applies: The greater the layer thickness of the coating 3, the lower the reflectivity of the coating 3 for the laser radiation L.

[0149] Unlike the illustration in Figure 9, the coating 3 can also consist of only a single layer, as is possible in all other examples.

[0150] Furthermore, the statements relating to Figures 1 to 7 apply equally to Figures 8 and 9, and vice versa.

[0151] Figure 10 illustrates that different mirror reflectivities can be achieved in a multiple emitter 1. By separately energizing or optically pumping the first laser emitters in a first coating process and the second laser emitters in a second coating process, locally different coatings or mirror finishes with respect to layer thickness and layer composition, and thus characteristics of the individual laser emitters, can be achieved. For additional emitters per chip or semiconductor laser 1, this process can be extended by correspondingly further coating processes. 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0152] 24

[0153] It is also possible that different currents on the laser emitters result in different intensities at the output facets 22, and therefore different coating thicknesses can be deposited in one and the same process.

[0154] Through such different coatings 3 it is possible, for example, to achieve optical output powers that differ by at least a factor of two or a factor of five for each semiconductor component 1, even with laser emitters 2 that are identical in terms of the semiconductor layer sequence.

[0155] Furthermore, the statements relating to Figures 1 to 9 apply equally to Figure 10, and vice versa.

[0156] In the example shown in Figures 11 and 12, the semiconductor laser 1 has three emitters arranged in parallel: a centrally located main emitter strip 23 and two peripheral secondary emitter strips 24. Only the main emitter strip 23 is configured to be operated during the operation of the finished semiconductor laser 1. The main emitter strips 23 are only operated during the manufacturing process.

[0157] By operating the secondary emitter strips 24, the relatively thick coating 3 is produced on their facets 22 in this example. The coating 3 acts as a lateral aperture 43 for the main emitter strip 23. This prevents unwanted lateral radiation from the main emitter strip 23 from leaving the semiconductor laser 1.

[0158] The aperture 43 and the associated coating 3 can be constructed from several coating materials 30, in the 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0159] 25

[0160] Figures 11 and 12 are not shown. For example, an inner coating material 30 is transparent to the laser radiation L, so that comparatively large apertures 43 are possible. An outer coating material 30, which is opaque and / or absorbs the laser radiation L or is reflective, can be applied to this inner coating material 30.

[0161] For example, the distance between the emitter strips 23, 24 is at least 2 pm and / or at most 50 pm, in particular at least 4 pm and at most 30 pm.

[0162] Other forms, numbers and positions of the secondary emitter strips 24 are also possible.

[0163] By applying current or by optical pumping functional structures, such as the secondary emitter strips 24, coatings 3 can be deposited in the vicinity of optically active structures, such as the main emitter strip 23, which are advantageous for the component 1.

[0164] Furthermore, the statements relating to Figures 1 to 10 apply equally to Figures 11 and 12, and vice versa.

[0165] In the example of the semiconductor laser 1 in Figure 13, it is shown that, according to an intensity distribution I, which is only shown schematically, a lens-shaped structure, such as a microlens, can also be created by the coating 3. This applies in particular to laser emitters 2 that can be operated in monomode. Such a coating can be used for beam collimation or beam focusing. 2024PF00793 8 October 2025 P2024, 0729 WO N

[0166] 26

[0167] The strength of a collimating or focusing effect can optionally be adjusted by the duration of the coating application. Since the laser emitter 2 is operated during the application of the coating 3, it is possible to monitor this in real time, for example using a camera, and to control the coating process accordingly.

[0168] Furthermore, the statements relating to Figures 1 to 12 apply equally to Figure 13, and vice versa.

[0169] As mentioned at the beginning, the examples each depict semiconductor laser 1 and laser emitter 2. The same method can be used to manufacture optoelectronic semiconductor components, where facets of light-emitting optoelectronic semiconductor bodies, such as LEDs or VCSELs, are coated.

[0170] The components shown in the figures preferably follow one another in the specified order, and in particular directly one after the other, unless otherwise described. Components that do not touch each other in the figures preferably have a distance between them. If lines are drawn parallel to each other, the associated surfaces are preferably also aligned parallel to each other. Furthermore, the relative positions of the drawn components to each other are correctly represented in the figures, unless otherwise specified.

[0171] The invention described here 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 2024PF00793 8 October 2025 P2024, 0729 WO N

[0172] - 27 - this feature or combination is not itself explicitly stated in the patent claims or embodiments. This patent application claims priority from German patent application 10 2024 132 249.7, the disclosure content of which is hereby incorporated by reference.

[0173] 2024PF00793 8 October 2025 P2024 , 0729 WO N

[0174] - 28 -

[0175] Reference character list

[0176] 1 semiconductor laser

[0177] 2 laser emitters

[0178] 20 emitter cluster

[0179] 21 Semiconductor layer sequence

[0180] 22 facets

[0181] 23 main emitter strips

[0182] 24 secondary emitter strips

[0183] 25 active zone

[0184] 26 Top electrode

[0185] 27 Bridge waveguides

[0186] 3 coating

[0187] 30 coating material

[0188] 31 first coating area

[0189] 32 second coating area

[0190] 41 Precursor gas

[0191] 42 Pre-coating

[0192] 43 aperture

[0193] 5 joint sponsors

[0194] 61 electrical p-contacting

[0195] 62 electrical n-contacts

[0196] I Intensity of the laser modes

[0197] L Laser radiation t local layer thickness of the coating

[0198] S process step

[0199] T Maximum layer thickness of the coating x Location coordinate

Claims

2024PF00793 October 8, 2025 P2024, 0729 WO N Patent claims 1. Method for the fabrication of semiconductor lasers (1) comprising the steps: - Providing a plurality of laser emitters (2) , wherein at least one facet (22) of each of the laser emitters (2) is exposed, - electrical or optical pumping of the laser emitters (2) so that the laser emitters (2) emit a laser radiation (L), - Generating a coating (3) on the facets (22) , wherein a local layer thickness (t) of the coating (3) across the facets (22) is determined by a locally present intensity (I) of the laser radiation (L).

2. The method according to the preceding claim, wherein the production of the coating (3) comprises: - Providing a precursor gas (41) for a coating material (30) of the coating (3) at the facets (22) , - Decomposition of the precursor gas (41) by the laser radiation (L) , and - Deposition of the coating material (30) at the facets (22) .

3. A method according to the preceding claim, wherein the precursor gas (41) comprises or consists of one or more substances from the following group: - tetraethyl orthosilicate, TEOS, - Trimethylgallium, TMGa, - Tert-butylimido tris-diethylamido tantalum, Ta (N^Bu) (NEtgJ g, TBTDET, 2024PF00793 October 8, 2025 P2024, 0729 WO N 30 - Ta (Ntßu) (NEt2) 2 C P< TBDETCp, - Tetrakis (dimethylamino) hafnium, TDMAH, - Tetrakis (ethylmethylamino) hafnium, TEMAHf, - Niobeth oxide, Nb (002115) 5, - aluminum acrylate, Al (OH) 2 (OOC-CH=CH2), - Organoalumoxane aluminum.

4. Method according to one of the preceding claims, wherein the local layer thickness (t) of the finished coating (3) across the facets (22) is proportional to the locally present intensity of the laser radiation (L) during the deposition of the coating material (30).

5. Method according to one of the preceding claims, wherein the coating (3) is produced only at locations of the facets (22) where the locally present intensity of the laser radiation (L) exceeds a threshold value greater than zero.

6. A method according to any of the preceding claims, wherein the coating (3) is applied to a pre-coating (42), the pre-coating (42) being a Bragg mirror or an anti-reflective coating.

7. Method according to the preceding claim, wherein the pre-coating (42) has a constant coating thickness.

8. A method according to any of the preceding claims, wherein the laser emitters (2) comprise a primary emitter strip (23) and a secondary emitter strip (24), the secondary emitter strip (24) being located next to the 2024PF00793 October 8, 2025 P2024, 0729 WO N The main emitter strip (23) is arranged and is only operated during the production of the coating (3).

9. Method according to the preceding claim, wherein only one facet (22) of the secondary emitter strip is (24) the coating (3) is applied so that an aperture (43) for the main emitter strip (23) is created on the secondary emitter strip (24).

10. Method according to one of the preceding claims, wherein the local layer thickness (t) of the finished coating (3) varies across the facets (22) by at least 30% of a maximum thickness (T) of the coating (3).

11. Method according to one of the preceding claims, wherein the laser radiation (L) has a wavelength of maximum intensity of at least 290 nm and at most 530 nm .

12. Method according to one of the preceding claims, wherein at least some of the laser emitters (2) are operated simultaneously during electrical or optical pumping.

13. Method according to one of the preceding claims, wherein the production of the coating (3) is carried out using a non-directional coating process.

14. Method according to any of the preceding claims, wherein providing the plurality of laser emitters (2) comprises: - Providing an emitter array (20) in which the laser emitters (2) are arranged on a common support (5) in a fixed position relative to each other, 2024PF00793 October 8, 2025 P2024, 0729 WO N 32 wherein the process after producing the coating (3) further comprises: - Dividing the emitter array (20) into emitter groups, each containing at least two of the laser emitters (2) .

15. Semiconductor laser (1) produced by a method according to one of the preceding claims, wherein the facet (22) has the coating (3) with the varying local layer thickness (t).

16. Semiconductor laser (1) according to the preceding claim, wherein the coating (3) comprises or consists of one or more of the following materials: silicon oxide, aluminum oxide, tantalum oxide, hafnium oxide, niobium oxide.

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