Growth substrate and method for manufacturing a growth substrate

Abstract

A growth substrate with the following features is provided: - a base layer (1), - a mask layer (2) arranged on the base layer (1), the mask layer (2) comprises openings (3), - epitaxial core elements (4) arranged within the openings (3), - epitaxial wing elements (6) arranged on or over the mask layer (2), wherein at least one stress-reducing layer (7) is arranged within the epitaxial wing elements (6). Further, a method for manufacturing a growth substrate is provided.

Description

[0001] 2024PF00648 September 25 , 2025

[0002] P2024 , 0769 WO N

[0003] - 1 -

[0004] Description

[0005] GROWTH SUBSTRATE AND METHOD FOR MANUFACTURING A GROWTH SUBSTRATE

[0006] A growth substrate and a method for manufacturing a growth substrate are provided .

[0007] An improved growth substrate is to be provided . Further, a simpli fied method for manufacturing an improved growth substrate is to be provided .

[0008] These obj ects are achieved with a growth substrate having the features of claim 1 and a method with the steps of claim 17 .

[0009] Improved developments and embodiments of the growth substrate and the method for manufacturing a growth substrate are given in the dependent claims .

[0010] According to an embodiment , the growth substrate comprises a base layer . Particularly, the base layer comprises or consists of a crystalline material . Particularly, the base layer has a growth surface configured for epitaxial growth of a semiconductor material . For example , the base layer is epitaxially grown on a substrate .

[0011] According to a further embodiment , the growth substrate comprises a mask layer arranged on the base layer, the mask layer comprises openings . Particularly, the mask layer is arranged on the base layer in direct contact therewith . Particularly, the mask layer comprises or consists of at least one dielectric material , such as a nitride , an oxide or 2024PF00648 September 25 , 2025

[0012] P2024 , 0769 WO N

[0013] - 2 - an oxynitride . For example , the mask layer comprises or consists of silicon oxide or silicon nitride .

[0014] For example , the openings within the mask layer have the same geometry . It is also possible that the openings are formed di f ferent from each other . For example , a base area of the openings has the same geometry . For example , the base area of the openings is strip-shaped .

[0015] According to a further embodiment , the growth substrate comprises epitaxial core elements arranged within the openings . Particularly, the epitaxial core elements are epitaxially grown within the openings on the growth surface of the base layer . In particular, the epitaxial core elements are part of an epitaxial semiconductor layer sequence grown on the growth surface of the base layer . Particularly, the base layer has epitaxial semiconductor layers stacked on top of each other in a stacking direction . For example , the epitaxial core elements fill the openings completely . For example , the epitaxial core elements are flush with a surface of the mask layer .

[0016] According to a further embodiment , the growth substrate comprises epitaxial wing elements arranged on or over the mask layer . Particularly, the epitaxial wing elements are also part of the epitaxial semiconductor layer sequence comprising the epitaxial core elements . Particularly, the epitaxial wing elements are in direct contact with the epitaxial core elements . For example , the epitaxial wing elements are epitaxially grown from the same semiconductor material as the epitaxial core elements . Also , the epitaxial wing elements are formed from or comprise a plurality of epitaxially grown semiconductor layers , the epitaxially grown 2024PF00648 September 25 , 2025

[0017] P2024 , 0769 WO N

[0018] - 3 - semiconductor layers being part of the epitaxial semiconductor layer sequence comprising the epitaxial core elements . For example , the epitaxial wing elements are flush with the epitaxial core elements .

[0019] Starting from the mask layer, the epitaxial wing elements extend continuously from the epitaxial core elements , for example . The epitaxial wing elements particularly extend laterally over the mask layer starting from the epitaxial core elements . The epitaxial wing elements comprise or consist of the same semiconductor material as the epitaxial core elements , for example .

[0020] According to a further embodiment of the growth substrate , at least one stress-reducing layer is arranged within the epitaxial wing elements . A thickness of the stress-reducing layer is , for example , between and including 1 nanometer and 500 nanometer . Particularly, the stress-reducing layer reduces a mechanical stress within the epitaxial wing elements . For example , the stress-reducing layer leads to negligible anisotropic mechanical stress within the epitaxial wing elements in the stacking direction . Particularly, the at least one stress-reducing layer leads to a high-quality growth substrate with strain engineering in the epitaxial wing elements .

[0021] Particularly, the base layer and / or the epitaxial core elements comprise defects . However, the outermost layers of epitaxial wing elements are preferably single crystalline and defect free .

[0022] Also , the stress-reducing layer is part of the epitaxial semiconductor layer sequence comprising the epitaxial wing 2024PF00648 September 25 , 2025

[0023] P2024 , 0769 WO N

[0024] 4 elements and the epitaxial core elements and is epitaxially grown within the epitaxial wing elements . Particularly, the stress-reducing layer comprises or consists of a di f ferent semiconductor material than the epitaxial wing element and / or the epitaxial core elements .

[0025] According to an embodiment , the growth substrate comprises :

[0026] - the base layer,

[0027] - the mask layer arranged on the base layer, the mask layer comprises the openings ,

[0028] - the epitaxial core elements arranged within the openings ,

[0029] - the epitaxial wing elements arranged on or over the mask layer, wherein the at least one stress-reducing layer is arranged within the epitaxial wing elements .

[0030] The growth substrate is inter alia based on the idea that the crystal quality of the growth substrate is enhanced due to the stress-reducing layer . Particularly, the stress-reducing layer reduces a tilt of the epitaxial wing elements with respect to the epitaxial core elements . Thus , a growth surface of the growth substrate for single crystalline growth of a further epitaxial semiconductor layer sequence is improved . For example , the growth surface of the growth substrate is a surface of the epitaxial wing elements being preferably free of defects .

[0031] Particularly, the growth substrate allows the epitaxial growth of the further epitaxial semiconductor layer sequence , preventing the formation of extended defects like stacking faults , stacking mismatch boundaries or chains of threading dislocations such as edge , screw or mixed dislocations . 2024PF00648 September 25 , 2025

[0032] P2024 , 0769 WO N

[0033] - 5 -

[0034] The growth substrate is particularly configured for epitaxial growth of a further epitaxial semiconductor layer sequence having an active radiation-generating zone . In that case , the growth substrate might be used for epitaxial growth of a further epitaxial semiconductor layer sequence of a lightemitting diode chip and / or a semiconductor laser chip . It is also possible to grow further epitaxial semiconductor layer sequences of electronic devices such as lateral high electron mobility transistors (HEMTs ) or vertical metal oxide semiconductor field-ef fect transistors (MOSFETs ) on the growth substrate .

[0035] Particularly, further epitaxial layer sequences , for example of edge-emitting laser chips , VCSEL chips , light-emitting diode chips , lateral high electron mobility transistors or vertical metal oxide semiconductor field-ef fect transistors can be epitaxially grown with improved quality on the growth substrate .

[0036] According to a further embodiment of the growth substrate , the epitaxial wing elements extend laterally from the epitaxial core element over the mask layer . Particularly, the epitaxial wing elements are epitaxially grown by epitaxial lateral overgrowth ( short : "ELOG" ) and therefore extend laterally from the epitaxial core element over the mask layer . The epitaxial lateral overgrowth is particularly achieved by speci fically defined growth conditions di f ferent from the growth conditions of the vertical epitaxial growth of the epitaxial core elements . Preferably, the epitaxial wing elements have a large extension in a lateral direction . So , the defect free surface of the epitaxial wing elements can be enhanced . 2024PF00648 September 25 , 2025

[0037] P2024 , 0769 WO N

[0038] - 6 -

[0039] Particularly preferably, two directly adj acent epitaxial wing elements do not coalesce during epitaxial growth . Particularly preferably, a region of the mask layer between two directly adj acent wing elements is freely accessible .

[0040] According to a further embodiment of the growth substrate , there is no further semiconductor material between the epitaxial wing elements and the mask layer . However, the epitaxial wing elements are not epitaxially grown on the mask layer, because the mask layer does not form a growth surface for the epitaxial wing elements . There are , particularly, no covalent bonds between the mask layer and the epitaxial wing elements . For example , there is van-der-Waal-attraction between the epitaxial wing elements and the mask layer . In particular, lateral epitaxial growth of the epitaxial wing elements starts from the epitaxially grown epitaxial core elements .

[0041] According to a further embodiment of the growth substrate , the openings are strip-shaped and arranged parallel to each other . Particularly preferably, the base area of the openings is strip-shaped and the base area of the openings has the same geometry . A width of the strip-shaped openings is , for example , between and including 100 nanometer to 5 micrometer .

[0042] Particularly, the geometry of the epitaxial core elements and the epitaxial wing elements is at least similar to the geometry of the openings . In other words , also the epitaxial core elements and the epitaxial wing elements are stripshaped . 2024PF00648 September 25 , 2025

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[0044] - 7 -

[0045] According to a further embodiment of the growth substrate , the epitaxial core elements and the epitaxial wing elements form strip-shaped elements extending parallelly to each other over the base layer . Particularly preferably, the stripshaped elements are embodied continuously without disruptions . Particularly, the strip-shaped elements are separated from each other . Particularly, between the epitaxial wing elements of two directly adj acent strip-shaped elements , a region of the mask layer is freely accessible .

[0046] According to a further embodiment of the growth substrate , a width of the strip-shaped elements is at least 20 micrometer . An upper limit of the width of the strip-shaped element is 250 micrometer, for example .

[0047] According to a further embodiment , the growth substrate is based on a nitride compound semiconductor material . Nitride compound semiconductor materials are compound semiconductor materials containing nitrogen, such as the materials from the system InxAlyGai-x-yN with 0 < x < 1 , 0 < y < 1 and x+y < 1 . In other words , the base layer, the epitaxial core element , the epitaxial wing element and / or the stress-reducing layer comprise or consist of a nitride compound semiconductor material . Particularly, a growth substrate based on a nitride compound semiconductor material is configured for epitaxial growth of a further epitaxial layer sequence based on a nitride compound semiconductor material .

[0048] For example , the base layer comprises or consists of gallium nitride ( GaN) . Also , the epitaxial wing elements and / or the epitaxial core elements comprise or consist of GaN . In other words , the growth substrate is configured for the epitaxial growth of a gallium-nitride-based semiconductor layer 2024PF00648 September 25, 2025

[0049] P2024, 0769 WO N

[0050] - 8 - sequence. Particularly, the stress-reducing layer has a different material composition than the surrounding semiconductor material of the epitaxial wing element. If the stress-reducing layer is directly adjacent to the epitaxial core element, it also has a different material composition than the adjacent epitaxial core element, for example.

[0051] For example, the stress-reducing layer comprises or consists of (Al,In)GaN. In other words, the semiconductor material of the stress-reducing layer comprises in each case gallium and nitrogen, while aluminium and indium are optional.

[0052] According to a further embodiment of the growth substrate, two or more stress-reducing layers are arranged within the epitaxial wing elements. For example, the stress-reducing layers have the same or a different material composition. Particularly, the stress-reducing layers have a material composition different from the surrounding semiconductor material .

[0053] According to a further embodiment of the growth substrate, the stress-reducing layers form a superlattice. Particularly, the superlattice is a periodic structure formed of the two or more stress-reducing layers. Particularly, the superlattice is formed of a sequence of stress-reducing layers having different material compositions and are repeated periodically. For example, the superlattice comprises or consists of a plurality of alternating (Al,In)GaN / (Al,In)GaN layers having different compositions.

[0054] According to a further embodiment, the growth substrate is a wafer. Particularly, the growth substrate formed as a wafer has a main extension plane and a thickness between a first 2024PF00648 September 25, 2025

[0055] P2024, 0769 WO N

[0056] 9 main surface and an oppositely arranged second main surface being much smaller than an area of the main surfaces. For example, the growth substrate is at least a 2", 4" but preferably 6" wafer. In other words, a diameter of the growth substrate is at least 6".

[0057] According to a further embodiment of the growth substrate, a semiconductor material of the epitaxial wing elements comprises Mg. In this case, a width of the epitaxial wing elements can be formed particularly broad. Since a surface of the epitaxial wing elements is intended as a growth surface for the epitaxial growth of a further epitaxial semiconductor layer sequence during manufacturing of a semiconductor chip at a later stage, broad epitaxial wing elements having a large width are advantageous.

[0058] According to a further embodiment of the growth substrate, a diffusion blocking layer is arranged on the epitaxial wing elements, the diffusion blocking layer is configured for inhibiting the diffusion of Mg. Particularly, if a further epitaxial semiconductor layer sequence with an active radiation generating zone is grown on the epitaxial wing elements, the diffusion blocking layer helps to prohibit diffusion of Mg in the active zone being very sensitive to Mg .

[0059] For example, at least a part of the growth substrate is comprised by a light-emitting diode chip. For example, an epitaxial wing element is comprised by the light-emitting diode chip. Features and embodiments of the growth substrate can therefore also be embodied within the light-emitting diode chip and vice versa. 2024PF00648 September 25 , 2025

[0060] P2024 , 0769 WO N

[0061] - 10 -

[0062] Further, it is possible that at least a part of the growth substrate is comprised by a semiconductor laser chip . For example , the semiconductor laser chip is an edge emitting semiconductor laser chip or a vertical cavity surface emitting laser chip (VCSEL-chip ) . For example , an epitaxial wing element is comprised by the semiconductor laser chip . Features and embodiments of the growth substrate can therefore also be embodied within the semiconductor laser chip and vice versa .

[0063] The light-emitting diode chip and / or the semiconductor laser chip are configured to be used in visuali zation and sensing applications , for example . For example , the light-emitting diode chip and / or the semiconductor laser chip is part of an augmented reality data glass , a virtual reality data glass or a LiDAR ( short for : "Light Detection and Ranging" ) device .

[0064] The growth substrate described herein can be manufactured using the method described in the following . Therefore , all embodiments and features described in connection with the growth substrate can also be embodied within the method and vice versa .

[0065] According to an embodiment of the method, a base layer is provided . For example , the base layer is arranged on a substrate providing mechanical stability to the growth substrate . For example , the substrate is a growth substrate for the base layer . For example , the base layer is epitaxially grown on the substrate . For example , the substrate comprises or consists of sapphire or silicon . It is also possible that the base layer is provided without a substrate . In that case , the base layer is , for example , a 2024PF00648 September 25 , 2025

[0066] P2024 , 0769 WO N

[0067] - 11 - wafer . Particularly, the base layer comprises a single crystalline semiconductor material having defects .

[0068] According to a further embodiment of the method, a mask layer with openings is deposited on the base layer, such that the base layer is accessible through the openings . For example , the mask layer is deposited on the base layer by sputtering, physical vapor deposition or chemical vapor deposition . The openings within the mask layer are , for example , manufactured with the help of a lithographic mask .

[0069] According to a further embodiment of the method, epitaxial core elements are vertically epitaxially grown within the openings . In other words , a semiconductor material of the epitaxial core elements is epitaxially deposited within the openings and forms semiconductor layers along a stacking direction of the epitaxial core elements . Particularly, defects and dislocations of the base layer continue in the epitaxial core elements during vertical epitaxial growth of the epitaxial core elements .

[0070] According to a further embodiment of the method, epitaxial wing elements are laterally epitaxially grown on the mask layer . For lateral epitaxial growth of the epitaxial wing elements , growth conditions of the semiconductor material are changed so that the epitaxial growth takes place at least partially in a lateral direction perpendicular to the stacking direction . Particularly, the epitaxial wing elements are grown laterally in the lateral direction so that the epitaxial wing elements extend over the mask layer .

[0071] During the lateral epitaxial growth of the epitaxial wing elements no defects occur, in particular . Defects and 2024PF00648 September 25 , 2025

[0072] P2024 , 0769 WO N

[0073] - 12 - dislocations within the core elements run almost fully in the vertical direction in most cases , while a lateral epitaxial growth of the epitaxial wing elements starting from side walls of the epitaxial core elements is nearly or fully defect free . A turning and / or bending of defects and dislocation from the epitaxial core elements in the epitaxial wing elements does not takes place during the present method, in particular . Particularly, a surface of the epitaxial wing elements is at least almost defect free . The term "almost" means in this context that the defects are negligible for the epitaxial growth of a further epitaxial semiconductor layer sequence comprising, particularly, an active radiation generating zone .

[0074] According to a further embodiment of the method, at least one stress-reducing layer is arranged within the epitaxial wing elements . Particularly, the stress-reducing layer is also epitaxially deposited during the epitaxial growth of the epitaxial wing elements by using di f ferent semiconductor materials than for the epitaxial growth of the epitaxial wing elements .

[0075] According to a further embodiment , the method for manufacturing the growth substrate comprises the steps of :

[0076] - providing the base layer,

[0077] - depositing the mask layer with the openings on the base layer, such that the base layer is accessible through the openings ,

[0078] - vertically epitaxially growing the epitaxial core elements within the openings ,

[0079] - laterally epitaxially growing the epitaxial wing elements on or over the mask layer, wherein 2024PF00648 September 25 , 2025

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[0081] - 13 - the at least one stress-reducing layer is arranged within the epitaxial wing elements .

[0082] I f there are more than one stress-reducing layers arranged within the epitaxial wing elements , the stress-reducing layers are deposited at various stages during laterally epitaxially growing the epitaxial wing elements . Particularly, the stress-reducing layers are configured to counteract or oppose the mechanical strain that is induced during the later epitaxial growth of the epitaxial wing element .

[0083] According to a further embodiment of the method, defects of the base layer continue in the epitaxial core elements during their vertical epitaxial growth . In other words , crystal defects within the base layer, such as dislocations , continue in the epitaxial core elements , particularly . For example , the epitaxial core elements have the same or a similar density of crystal defects as the base layer .

[0084] According to a further embodiment of the method, the lateral epitaxial growth of the epitaxial wing elements starts at side faces of the epitaxial core elements . Particularly, during the lateral epitaxial growth of the epitaxial wing elements low defects density within the semiconductor material of the epitaxial wing elements occur . Particularly, the semiconductor material of the epitaxial wing elements has a defect density much smaller than a defect density of the epitaxial core elements and / or the base layer . For example , the defect density of the epitaxial wing elements is smaller than the defect density of epitaxial core elements and / or the base layer by at least a factor 100 or at least a factor 1000 . 2024PF00648 September 25 , 2025

[0085] P2024 , 0769 WO N

[0086] 14

[0087] It is an idea of the present method for manufacturing a growth substrate to grow the epitaxial wing elements laterally starting from the epitaxial core elements to reduce the defect density within the epitaxially grown semiconductor material of the epitaxial wing elements signi ficantly . Thus , a surface of the epitaxial wing elements is created in a at least mostly defect- free manner . The surface of epitaxial wing elements can be therefore used as a growth surface for a further epitaxial semiconductor layer sequence comprising, for example , an active radiation generating zone .

[0088] Further advantageous embodiments and developments of the growth substrate and the method for manufacturing a growth substrate result from the exemplary embodiment described below in connection with the Figures .

[0089] Figures 1 to 5 show schematic cross-sectional views of stages of a method for manufacturing a growth substrate according to an exemplary embodiment .

[0090] Figures 6 and 7 show schematic views of a growth substrate according to an exemplary embodiment .

[0091] Figures 8 and 9 show schematic views of a growth substrate according to a further exemplary embodiment .

[0092] Figure 10 shows a schematic sectional view of a growth substrate according to a further exemplary embodiment .

[0093] Figure 11 shows a rocking curve of a ( 0002 ) -GaN plane of a growth substrate with and without a stress-reducing layer . 2024PF00648 September 25 , 2025

[0094] P2024 , 0769 WO N

[0095] - 15 -

[0096] Equal or similar elements as well as elements of equal function are designated with the same reference signs in the Figures . The Figures and the proportions of the elements shown in the Figures are not regarded as being shown to scale . Rather, single elements , in particular layers , can be shown exaggerated in magnitude for the sake of better presentation and / or better understanding .

[0097] During the method according to the exemplary embodiment of Figures 1 to 5 , a base layer 1 is provided in a first step ( Figure 1 ) . The base layer 1 comprises , for example , gallium nitride and extends in a main extension plane . At present , the base layer 1 is provided on a substrate 16 for mechanical stability . For example , the base layer 1 is epitaxially grown on the substrate 16 . The base layer 1 , for example , comprises or consists of GaN, while the substrate 16 comprises or consists of sapphire or silicon .

[0098] In a next step, as schematically shown in Figure 2 , a mask layer 2 is deposited on a main surface of the base layer 1 . The mask layer 2 , for example , comprises or consists of a dielectric material such as an oxide or a nitride .

[0099] The mask layer 2 further comprises openings 3 extending in a strip-shaped manner in parallel over the main surface of the base layer 1 . The main surface of the base layer 1 is accessible through the openings 3 . Particularly, the main surface of the base layer 1 forms a growth surface for a nitride compound semiconductor material .

[0100] In a next step, as for example shown in Figure 3 , epitaxial core elements 4 are vertically epitaxially grown within the openings 3 of the mask layer 2 . Particularly, the vertical 2024PF00648 September 25 , 2025

[0101] P2024 , 0769 WO N

[0102] - 16 - epitaxial growth of the epitaxial core elements 4 takes place in a vertical stacking direction Dsof the semiconductor layers of an epitaxial semiconductor layer sequence 5 comprising the epitaxial core elements 4 . The epitaxial core elements 4 are , as the openings 3 , strip-shaped . A lateral direction DLruns perpendicular to the stacking direction Ds.

[0103] Then, in a next step, the growth conditions are modi fied such that epitaxial wing elements 6 are epitaxially grown in the lateral direction DL( Figure 4 ) . The epitaxial wing elements 6 extend over the mask layer 2 . Further, the epitaxial wing elements 6 comprise a stress-reducing layer 7 .

[0104] The stress-reducing layer 7 covers in this exemplary embodiment an end face 8 of the strip-shaped epitaxial core elements 4 and further at least partially side faces 9 of the epitaxial core elements 4 . At present , the stress-reducing layer 7 comprises or consists of (Al , In) GaN . The stressreducing layer 7 of the epitaxial wing elements 6 are equally embodied at the present .

[0105] The epitaxial core elements 4 and the epitaxial wing elements 6 are formed of the epitaxial semiconductor layer sequence 5 having epitaxial semiconductor layer grown above each other in stacking direction Ds.

[0106] The epitaxial core elements 4 and the epitaxial wing elements 6 form strip-shaped elements 10 extending parallel over the base layer 1 on or over the mask layer 2 . The strip-shaped elements 10 are separated from each other and not coalesced . Regions 11 of the mask layer 2 are freely accessible between the epitaxial wing elements 6 of two directly adj acent stripshaped elements 10 . 2024PF00648 September 25 , 2025

[0107] P2024 , 0769 WO N

[0108] - 17 -

[0109] Figure 5 shows the detail of Figure 4 marked with an A. As can be seen in Figure 5 , the base layer 1 comprises dislocations 17 . The dislocations 17 continue within the epitaxial core elements 4 during the vertical epitaxial growth of the epitaxial core elements 4 but not on the epitaxial wing elements 6 . A surface 18 of the epitaxial wing elements 6 is therefore free of crystal defects such as dislocations 17 . Particularly, the surface 18 of the epitaxial wing elements 6 is configured for epitaxial growth of a further epitaxial semiconductor layer sequence .

[0110] The growth substrate 12 according to the exemplary embodiment of Figures 6 and 7 can be manufactured with the method according to Figures 1 to 5 .

[0111] The growth substrate 12 of Figures 6 and 7 comprises a base layer 1 covered with a mask layer 2 . The mask layer 2 has openings 3 which extend in a strip-shaped manner over a main surface of the base layer 2 . Within the openings 3 , epitaxial core elements 4 are arranged . The epitaxial core elements 4 are , as the openings 3 , strip-shaped and extend in parallel over the main surface of the base layer 1 .

[0112] Epitaxial wing elements 6 extend laterally from the epitaxial core elements 4 . The epitaxial wing elements 6 and the epitaxial core elements 4 form strip-shaped elements 10 extending in parallel over the main surface of the base layer 1 . The strip-shaped elements 10 are separated from each other and not coalesced . Regions 11 of the mask layer 2 between two directly adj acent strip-shaped elements 10 are freely accessible . The openings 3 , the strip-shaped elements 10 , the 2024PF00648 September 25 , 2025

[0113] P2024 , 0769 WO N

[0114] - 18 - epitaxial wing elements 6 and the epitaxial core elements 4 are embodied equal in the present exemplary embodiment .

[0115] The growth substrate 12 of the exemplary embodiment of Figures 6 and 7 is a wafer 13 having, for example , a diameter of 150 millimeter . Here , only two strip-shaped elements 10 are shown exemplarily . However, there is a plurality of strip-shaped elements 10 extending in parallel over the main surface of the mask layer 2 of the growth substrate 12 embodied as a wafer 13 .

[0116] Further, in this case , each of the epitaxial wing elements 6 comprise a stress-reducing layer 7 arranged over the epitaxial core elements 4 . The stress-reducing layer 7 is configured for reducing mechanical stress within the epitaxial wing elements 6 and, as a consequence , within the strip-shaped elements 10 .

[0117] Compared to the growth substrate 12 of Figures 6 and 7 , the growth substrate 12 according to the exemplary embodiment of Figures 8 and 9 comprises an additional stress-reducing layer 7 within the epitaxial wing elements 6 . A shape of the further stress-reducing layer 7 is similar to that of the other stress-reducing layer 7 .

[0118] Figure 10 shows a schematic sectional view of a further exemplary embodiment of a growth substrate 12 . Compared to the growth substrate 12 of Figures 6 and 7 , the growth substrate 12 of Figure 10 comprises epitaxial wing elements 6 having a semiconductor material doped with Mg . For example , the semiconductor material of the epitaxial wing elements 6 is Mg-doped GaN . The use of Mg-doped GaN enables the 2024PF00648 September 25, 2025

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[0120] - 19 - epitaxial growth of large epitaxial wing elements 6 with a broad width with advantage.

[0121] Further, the growth substrate 12 of Figure 10 comprises a diffusion blocking layer 15 blocking the diffusion of Mg in a further semiconductor layer sequence 14. The diffusion blocking layer 15 is arranged on a surface 18 of the epitaxial wing elements 6 and also on a surface of the epitaxial core elements 4 being flush with the epitaxial wing elements 6.

[0122] Figure 11 shows an XRD measurement ("XRD" short for "x-ray diffraction") of a GaN (0002) rocking curve measured with rocking direction perpendicular to an extension of a stripshaped elements of a growth substrate 12, the growth substrate 12 comprises wing elements 6 with stress-reducing layers 7 as described above (curve Ci) . Further, Figure 11 shows an XRD measurement of a comparison example without a stress-reducing layer 7 as reference (curve Co) . The FWHM (short for "full width half maximum") of the exemplary embodiment with the stress-reducing layer 7 is 0.0829°, while the variance of the comparison example is 0.3118°. The strain and / or the tilt of the epitaxial wing elements can be determined with the help of x-ray diffraction (XRD, direct measurement of the lattice plane distortion within a certain volume) , electron backscatter diffraction (EBSD, direct measurement of the misorientation of lattice planes near to the surface) , cathodoluminescence imaging (CL, indirect proof of strain or absence thereof by imaging the resulting structural defects via their impact on the luminescence) , Raman microscopy (determination of strain from the shift of certain Raman modes) , for example. 2024PF00648 September 25 , 2025

[0123] P2024 , 0769 WO N

[0124] - 20 -

[0125] The present application claims priority of the German application DE 102024132427 . 9 , the disclosure content of which is incorporated herein by reference . The features and exemplary embodiments described in connection with the Figures can be combined with each other according to further exemplary embodiments , even i f not all combinations are explicitly described . Furthermore , the exemplary embodiments described in connection with the Figures may alternatively or additionally have further features according to the description in the general part .

[0126] The invention is not limited to the description of the exemplary embodiments . Rather, the invention comprises each new feature as well as each combination of features , particularly each combination of features of the claims , even i f the feature or the combination of features itsel f is not explicitly given in the claims or the exemplary embodiments .

[0127] 2024PF00648 September 25 , 2025

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[0129] 21

[0130] References

[0131] 1 base layer

[0132] 2 mask layer

[0133] 3 opening

[0134] 4 epitaxial core element

[0135] 5 epitaxial semiconductor layer sequence comprising the epitaxial core elements and the wing elements

[0136] 6 epitaxial wing element

[0137] 7 stress-reducing layer

[0138] 8 end face of the epitaxial core element

[0139] 9 side face of the epitaxial core element

[0140] 10 strip-shaped element

[0141] 11 region of the mask layer

[0142] 12 growth substrate

[0143] 13 wafer

[0144] 14 further epitaxial semiconductor layer sequence

[0145] 15 di f fusion blocking layer

[0146] 16 substrate

[0147] 17 dislocation

[0148] 18 surface of the epitaxial wing element

[0149] DS stacking direction

[0150] DL lateral direction

Claims

2024PF00648 September 25, 2025P2024, 0769 WO N- 22 -Claims1. Growth substrate (12) comprising:- a base layer ( 1 ) ,- a mask layer (2) arranged on the base layer (1) , the mask layer (2) comprises openings (3) ,- epitaxial core elements (4) arranged within the openings (3) ,- epitaxial wing elements (6) arranged on or over the mask layer ( 2 ) , wherein at least one stress-reducing layer (7) is arranged within the epitaxial wing elements (6) .

2. Growth substrate (12) according to the previous claim, wherein the epitaxial wing elements (6) extend laterally from the epitaxial core element (4) over the mask layer (2) .

3. Growth substrate (12) according to any of the previous claims, wherein between the epitaxial wing elements (6) and the mask layer (2) there is no further semiconductor material.

4. Growth substrate (12) according to any of the previous claims, wherein the openings (3) are strip-shaped and arranged parallel to each other.2024PF00648 September 25, 2025P2024, 0769 WO N- 23 -5. Growth substrate (12) according to any of the previous claims, wherein the epitaxial core elements (4) and the epitaxial wing elements (6) form strip-shaped elements (10) extending parallelly to each other over the base layer (1) .

6. Growth substrate (12) according to the previous claim, wherein a width of the strip-shaped elements (10) is at least 20 micrometer .

7. Growth substrate (12) according to any of the previous claims, wherein the base layer (1) comprises GaN.

8. Growth substrate (12) according to any of the previous claims, wherein the epitaxial wing elements (6) and / or the epitaxial core elements (4) comprise GaN.

9. Growth substrate (12) according to any of the previous claims, wherein the stress-reducing layer (7) comprises (Al, In) GaN.

10. Growth substrate (12) according to any of the previous claims, wherein two or more stress-reducing layers (7) are arranged within the epitaxial wing elements (6) .

11. Growth substrate (12) according to the previous claim, wherein the stress-reducing layers (7) form a superlattice.2024PF00648 September 25, 2025P2024, 0769 WO N- 24 -12. Growth substrate (12) according to any of the previous claims, the growth substrate (12) being a wafer (13) .

13. Growth substrate (12) according to any of the previous claims, wherein a semiconductor material of the epitaxial wing elements (6) comprises Mg.

14. Growth substrate (16) according to the previous claim, wherein a diffusion blocking layer (15) is arranged on the epitaxial wing elements (6) , the diffusion blocking layer (15) is configured for inhibiting the diffusion of Mg.

15. Light-emitting diode chip comprising at least a part of a growth substrate (12) according to any of the previous claims .

16. Semiconductor laser chip comprising at least a part of a growth substrate (12) according to any of claims 1 to 14.

17. Method for manufacturing a growth substrate (12) , comprising the steps:- providing a base layer (1) ,- depositing a mask layer (2) with openings (3) on the base layer (1) , such that the base layer (1) is accessible through the openings (3) ,- vertically epitaxially growing epitaxial core elements (4) within the openings (3) ,- laterally epitaxially growing epitaxial wing elements (6) on or over the mask layer (2) , wherein at least one stress-reducing layer (7) is arranged within the epitaxial wing elements (6) .2024PF00648 September 25, 2025P2024, 0769 WO N- 25 -18. Method according to the previous claims, wherein defects of the base layer (1) continue in the epitaxial core elements (4) during their vertical epitaxial growth.

19. Method according to any of claims 17 or 18, wherein lateral epitaxial growth of the epitaxial wing elements (6) starts at side faces of the epitaxial core elements (4) .

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