Optoelectronic component, optoelectronic array and method

Abstract

The invention concerns an optoelectronic component, comprising a semiconductor layer stack comprising a first doped layer, a second doped region and an active region in between. The layer stack comprises mesa structured side facets of the active region and the first doped layer wherein the side facets form a first angle with regard to a plane normal to the active region. A semiconductor layer based on a nitride material system is regrown at least on side facets of the active region and the first doped layer and a surface portion of the first doped layer substantially parallel to the active region. The band gap of the regrown semiconductor layer is larger than a band gap of at least portions of the active region; and side surfaces of the regrown semiconductor layer form a third angle with regard to the plane normal onto the active region that is larger than the first and / or second angle. Finally, a contact layer is deposited on the second doped layer and at least partially extending on the regrown semiconductor layer.

Description

[0001] 2023PF01132 - 1 -OPTOELECTRONIC COMPONENT, OPTOELECTRONIC ARRAY AND METHOD The present application claims priority from German patent application DE 10 2024 104 386.5 dated February 16, 2024, the5 disclosure of which is incorporated herein by reference in itsentirety. The present invention concerns a method for processing a plurality of optoelectronic components. The present invention also concerns an optoelectronic component and an array of such optoelectronic components. 0 BACKGROUND Optoelectronic components are available in different forms, sizes and shapes. With respect to sizes, one can differentiate between LED5 having a lateral size larger than 100µm and so called µLED comprisinga lateral size of less than 50µm and particularly less than 20µm and particularly less than 10µm down to 1µm. While such µLEDs are available as separate components, they are often part of a monolithically integrated array comprising a plurality of such0 components arranged in a certain order.In case several optoelectronic components shall be processed at once, the components are usually epitaxially grown on a growth substrate, processed and then transferred as a common structure to the final5 carrier. Depending on design and application, the individuallycomponents or µLEDs of such array shall be addressed either individually, in groups or all at once. µLED structuring for achieving a monolithically integrated array with diameters smaller as 10µm results in considerable damage in semiconductor layers and0 therefore leads to a significant efficiency degradation. This effecthas been observed in several different material systems including but not limited to nitrides like GaN, AlGaN and InGaN and InAlGaN as well as phosphides like GaP, AlGaP and InGaP and InAlGaP. Since nitride systems can achieve light emission at different wavelengths from blue5 to almost red using different In contents, achieving a low defectdensity on its structured side facets is beneficial to increase the overall quantum efficiency.2023PF01132 - 2 -Another issue in those material systems is the pixel structuring without control of the pixel shape and its facets. It has been observed that facets that do not follow a certain growth often result in low light-extraction efficiency or enhanced optical crosstalk.5 Several methods are available to address the efficiency loss due toµLED structuring. For example, selective area growth has been proposed, wherein the emitting component is not structured. Alternatively, the layer stack of the various µLEDs are structures followed by defect etching and dielectric passivation. This approach0 improves efficiency but also requires complex semiconductorpassivation. It is an object of the present application to provide a method for an efficient processing of the optoelectronic components as well as such5 components, for which the light extraction efficiency is improved.SUMMARY OF THE INVENTION This and other objects are addressed by the subject matter of the independent claims. Features and further aspects of the proposed0 principles are outlined in the dependent claims.The inventors propose passivation and electrical insulation after structuring a layer stack forming the core of the optoelectronic component in one step. This is achieved by using an epitaxial5 regrowth of a high band gap layer. The epitaxial growth of thematerial can maximize the pixel efficiency due to the intrinsic high quality of epitaxial layers. The growth parameters enable to control the geometry of the pixel along certain crystallographic facets, thereby adjusting the surface angle of the pixel to more beneficial0 values.The various parameters provide a large spectrum of design choices, enabling different applications while maintaining a high internal quantum efficiency and a high light extraction efficiency. The5 proposed principle is suitable for arrays, which also face the issueof optical and / or electrical crosstalk. The proposed principle2023PF01132 - 3 -enables optimization of light generation and light extraction efficiency independently while minimizing the optical crosstalk. In some aspects, the inventors propose a method for processing a5 plurality of optoelectronic components. The method comprises the stepof providing a growth substrate. Then, a semiconductor layer stack based on a nitride material system is deposited on the growth substrate. More particularly, in some aspects, one or more buffer layers are first deposited on the growth substrate. The buffer layers0 form in some aspects a part of the growth substrate.The layer stack is formed for example by depositing a first doped layer on the growth substrate. The first doped layer may comprise a plurality of sub layers, which may contain different doping5 concentrations and / or material compositions. In some aspects, thefirst doped layer may comprise a doped sub layer acting as a current distribution layer. Other layers may act as transportation layer. In some further aspects, the first doped layer may comprise an undoped layer acting as a cladding layer to prevent a dopant diffusion from0 the first doped layer into an adjacent layer, in particular theactive region as outlined below. The layer stack also comprises an active region that is deposited on top of the first doped layer. The active region comprises a band gap5 that is at least partially smaller than a band gap of at leastportions of the first doped layer. In some instances, the active region comprises a multi-quantum well structure with alternating barrier and quantum well layers deposited on each other. The thickness of the barrier and quantum well layers may be different and0 range for example between 1.5 nm and 20 nm for example. Depending ondesign choices, the number of quantum well layers may range between 1 and 20 or even more. The material composition of the barrier layers and the quantum well5 layers, respectively are different in particular, the barrier layerscomprise a larger band gap than the respective quantum well layers, which may be caused by an increased Al content in the material2023PF01132 - 4 -composition. In some aspects, the quantum well layer may comprise In as a component of the material composition, an In content shifts the overall band gap to lower energies, that is towards longer wavelength. By choosing and adjusting the In content within the5 quantum well layers or more generally within the active region, lightwith wavelength between the near UV to the red spectrum can be achieved. In some aspects, another doped layer may be epitaxially deposited on0 the active region. The further doped layer comprises a doping typedifferent from the doping type of the first doped layer. The further doped layer may comprise one or more sub layer including different dopant concentrations and / or different material compositions. In some aspects, the further doped layer comprises an undoped cladding layer5 directly adjacent to the active region. The cladding layer cancomprise a thickness of a few 10 nm to appr 200 nm in some instances. The proposed method further comprises the step of providing a mask layer on top of the semiconductor layer stack. The mask layer is0 structured to form portions covering at least two portions of theactive region. The regions are laterally displaced to each other. In some aspects, portions of edges of the structured mask are substantially parallel to a crystallographic plane of the epitaxially deposited grown layer stack, in particular one of the a-plane and m-5 plane.The structured mask is used in the subsequent process step to conduct a mesa structuring process to form islands protruding above an etched surface. Particularly, the mesa structuring process exposes for each0 island side facets of the active region and the first doped layer anda surface portion of the first doped layer substantially parallel to the active region adjacent to each island. In accordance with the proposed principle, the mesa structured side facets for a first angle with regard to a plane normal onto the active region. In some5 aspects, side facets of the active region form the first angle, whilethe side facets of the first doped layer from a second angle with regard to the plane normal onto the active region. This first and2023PF01132 - 5 -second angle may be the same but can also be different. Typical angles are given further below. Those angles may follow certain crystallographic cutting planes, such that atoms of the material composition of the layer stack lie in such planes. 5 In accordance with the proposed method, a semiconductor layer based on a nitride material system is epitaxially regrown on each island. This regrowth process defines the geometry of the optoelectronic components. In particular, the semiconductor layer is regrown at0 least on the side facets of the active region and the first dopedlayer. Material of the semiconductor layer is also regrown on a surface portion of the first doped layer adjacent to the islands and substantially parallel to the active region. The side surfaces of the regrown semiconductor layer, that is the surfaces of the5 semiconductor layer covering the side facets of the structured layerstack of the respective islands, exhibit a third angle with regard to the plane normal onto the active region that is larger than the first and / or second angle.0 The present method allows flexible design parameters by adjusting thefirst and second angle, and respectively the third angle by subsequently growth step. The regrow process reduces the defect density thereby improving and optimizing the internal quantum efficiency, that is the generation of light in relation to the5 current through the component. The material of the regrow process ischosen to provide a higher band gap than the band gap of the material of the active region, thereby creating a potential repelling charge carrier from the side facets with that might still have a higher defect density as the inner area.0 In some aspects, the plane on which the layer stack is epitaxiallydeposited is the c-plane. The crystallographic plane to which the structured mask layer is aligned to may be the a-plane or the m- plane. Likewise, side facets at least close to the exposed surface portions of the first doped layer may comprise an angle of one of 0°,5 11°, 15° and 28°. Those angles correspond to the first and / or secondangle, respectively. It should be noted in this regard that Mesa structuring by plasma processes and / or mostly isotropic wet processes2023PF01132 - 6 -can result also in arbitrary angles. The third angle is larger than the first and second angle, and the surfaces of the regrown semiconductor layer may also follow certain crystallographic cut plane. Hence, the third angle is at least one of 39°, 47° and 58° or5 combinations thereof.Some aspects concern the step of providing a structured mask. The mask layer is structured in a way that the islands are laterally separated from each other. A distance between centers of the at least0 two portions of the semiconductor layer stack covered by the masklayer material is a function of the sum of a diameter of the mask portion and a value based on a depth of a recess separating two adjacent islands and the tangent of the third angle. This function is based on the prerequisite that the optoelectronic component with5 their respective regrown layer should be sufficiently set apart, sothat material of regrown layer of adjacent components do not overlap. Consequently, the above-mentioned distance is referred to as minimum distance. A distance larger than the minimum distance will generate optoelectronic components that are separated from each other and are0 only connected together by a material bridge of unetchedsemiconductor material. The minimum or larger distance reduces the optical crosstalk. Given by the above dependency, it is apparent that a larger third5 angle results in a larger minimum distance.Some further aspects concern the step of conducting a mesa structuring process to form islands. When viewed from the top, the islands may form a hexagonal island structure at an intersection0 between side facets of the first doped layer and the surface portionof the first doped layer. Due to the crystallographic plane, the shape and the hexagonal form can be adjusted in size and orientation. In some aspects, the intersection is aligned with the 1210 directionor its equivalences thereof. In some aspects, the structured mask can5 form the same hexagonal structure, although it may be smaller in sizethan the area at the intersection. In some other aspects, the structured mask can have another form like a circle, a square and the2023PF01132 - 7 -like, which may be easier to process. Still due to a self-alignment during the mesa structuring process, the above intersection may still align itself with the above-mentioned direction.5 Some aspects also relate to positioning the individual mask portionand thus the island being structured in the process on the growth substrate and / or portion of the first doped layer. In some aspects, the islands are arranged at central positions of a virtual hexagonal grid. In other words, the islands form a hexagonal pattern. In some0 aspects, the virtual grid is aligned to the m-planes defined as the1210 plane of the layer stack. In some other aspects, the islandsare arranged at central positions of a virtual gird of rows and columns. Such a virtual grid resembles a chess like patter. The virtual grid may in such cases be aligned to a-planes defined as the5 1110 plane of the layer stack. Other orientations and positioningare possible. It is also possible to leave certain position of the respective virtual grids unoccupied, e.g. occupy only each second central position of the above-mentioned virtual grids. Still even such positioning, in which not every position is occupied by an0 island shall be considered as hexagonal or chess pattern and grid.Some further aspects of the proposed method concern the step of conducting a mesa structuring process to form islands. For example, the active region and the first doped layer may be etched to a depth5 which follows a certain relationship, that ultimately also definesthe minimum distance. Alternatively, a desired distance between the individual components also defines the depth of the mesa structuring process. In some instances, the depth between a top surface of the layer stack and the surface portion of the first doped layer is0 proportional to 1 over the tangent of the third angle.The other aspects concern the step of epitaxially regrowing a semiconductor layer on each island. It is possible for example to epitaxially regrow a semiconductor layer on side facets of the active5 region and the first doped layer and the surface portion of the firstdoped layer. Due to the hexagonal structure (or more general not circular structure) edges are formed during the regrowth process,2023PF01132 - 8 -where two surfaces grown along differently oriented plane grow together. Depending on the position of the islands on the surface, edges of adjacent island may form an intersection (or its elongated projection). For example, edges of three adjacent islands form an5 intersection with an angle of appr. 120° in between.In some other aspects, the semiconductor layer is regrown on side facets of the active region and the first doped layer and the surface portion of the first doped layer such that an intersection of a0 regrown semiconductor layer on a side facet intersects with a portionof the regrown layer on the surface portion of the first doped layer substantially parallel to the 1210 direction or its equivalencesthereof.5 In some other aspect, the semiconductor layer is regrown on sidefacets of the active region, on side facets of the first doped layer and the surface portion of the first doped layer. The intersections of regrown semiconductor layers on side facets of two adjacent islands with the regrown layer on the surface portion of the first0 doped layer are aligned substantially parallel to each other.In some other aspects, the step of epitaxially regrowing a semiconductor layer on each island comprises the step of epitaxially regrowing a semiconductor layer on side facets of the active region,5 on side facets of the first doped layer and the surface portion ofthe first doped layer such that an edge between two adjacent surface regions of a regrown semiconductor layer of an island is facing an edge between two adjacent surface regions of a regrown semiconductor layer of an adjacent island. 0 In some aspects, the semiconductor layer is epitaxially regrown on side facets of the active region, on side facets of the first doped layer and the surface portion of the first doped layer such that intersections of regrown semiconductor layers on a side facets of two5 adjacent islands with the regrown layer on the surface portion of thefirst doped layer comprise an angle of appr. 120° in between. The2023PF01132 - 9 -intersections may be aligned to certain crystallographic planes, like the m-plane, for example. In some aspects, the distance between adjacent islands is increased such that a portion of the regrown layer on the surface portion is5 substantially parallel to the active region of the adjacent islandsafter the step of epitaxially regrowing a semiconductor layer on side facets of the active region, on side facets of the first doped layer and the surface portion of the first doped layer. The arrangement and position of the islands enable a large degree of freedom to adjust0 the growth parameter of the regrowth process, thus optimizing thelight extraction efficiency. Some other aspects concern the step of epitaxially regrowing a semiconductor layer on each island. In some aspects, regrowth5 conditions and parameters may be varied during epitaxially depositingthe material of the semiconductor layer. Such variation may include but is not limited to changing the dopant concentration, changing the material composition, i.e. by adding or changing the Al or In content thereof, changing pressure or temperature to modify the speed of the0 deposition process.In some aspects, the conditions are adjusted after some time to form first portions of the side surfaces comprising the third angle and second portions of the side surfaces comprising a fourth angle with5 regard to the plane normal onto the active region, the fourth anglebeing larger than the first and / or second angle. In some aspects, a third angle may be formed on side facets of the active region, while the fourth angle is deposited on side facets of the first doped layer. 0 In some aspects, the mask layer that is used for the mesa structuring process is removed completely, thereby exposing the top surface of the layer stack completely. The regrowth process will then also deposit material of the semiconductor layer also on the top surface.5 In some instance, one can form a second doped layer with the regrowthprocess. In other aspects, the mask layer is only partially removed to expose top surface portions of the semiconductor layer stack. The2023PF01132 - 10 -semiconductor layer is then epitaxially regrown on the exposed portions. The mask material can be removed in a subsequent step to form a recess for a contact material.5 In some further aspects, the step of conducting a mesa structuringprocess comprises conducting a first, in particular a dry etch process followed by a wet etch process. The wet etching process may be used to etch non-polar planes to obtain side facets of the active region and / or the first doped layer that are substantially vertical0 onto the surface portion of the first doped layer substantiallyparallel to the active region adjacent to each island. In some instances, a wet etching process is conducted using KOH and / or H3PO4. Different material compositions and / or dopant concentrations as well5 as dopants can be used for the regrown semiconductor layer. In someinstances, the regrown semiconductor layer may comprise an undoped GaN layer or an undoped Alx(Ga)1-xN layer with an Al content of x between 0.0005 and 0.05. Alternatively or additionally, the regrown semiconductor layer may comprise an undoped Iny(Ga)1-yN layer with an0 In content of between 0.001 and 0.02. The layers can be doped with Mgor Zn with a dopant concentration of 1e16 1 / cm³ to 8e18 1 / cm³. In some aspects, a pnp multilayer structure of GaN, AlGaN or InAlGaN is deposited. All the different material compositions and dopants and their concentrations can be combined. The regrown semiconductor layer5 may comprise one or more sub layers of different material compositionand / or dopants and dopant concentration. Finally, the method according to the proposed principle comprises, in some aspects, the step of removing the mask layer on top of the0 semiconductor layer and applying a contact layer on the exposedportions of the top. The contact layer may extend on portions of the regrown semiconductor layer. In some aspects, the contact layer comprises a reflective material, like a metal and / or a DBR structure. In some further aspects, the islands are separated from each other by5 etching though the contact layer between two opposing side surfacesof the regrown layer.2023PF01132 - 11 -The present invention also concerns an optoelectronic component. The optoelectronic component comprises a semiconductor layer stack, which is epitaxially deposited on a growth substrate in a growth direction perpendicular along the c-plane of its material. The semiconductor5 layer stack comprises a first doped layer and an active regionadjacent to the first doped layer and a second doped layer adjacent to the active region. The modifications, like sub-layers, material composition, dopant types and dopant concentration are specified above with regard to the method for processing such component. For0 example, the first doped layer and / or the second doped layer of thesemiconductor layer stack may comprise an in particular undoped cladding layer adjacent to the active region. In some aspects, the second doped layer of the semiconductor layer stack comprises an electron blocking layer based on an AlGaN composition adjacent to the5 active region.The active region comprises a band gap that is at least partially smaller than a band gap of at least portions of the first doped layer. 0 The optoelectronic component in accordance with the proposed principle, comprises mesa structured side facets of the active region and the first doped layer. The mesa structured side facets form a first angle with regard to a plane normal to the active region. In5 some aspects, side facets of the active region form a first anglewith regard to a plane normal to the active region; and side facets of the first doped layer from a second angle with regard to the plane normal onto the active region. The first and second angle can be equal but may also slightly differently depending on growth parameter0 and the structuring process forming the side facets.The optoelectronic component further comprises a regrown semiconductor layer based on a nitride material system at least on side facets of the active region and the first doped layer and a5 surface portion of the first doped layer substantially parallel tothe active region. A band gap of the regrown semiconductor layer is larger than a band gap of at least portions of the active region,2023PF01132 - 12 -thereby generating a potential barrier repelling charge carriers in the active regions from the interface of the side facets. In accordance with the proposed principle, side surfaces of the5 regrown semiconductor layer from a third angle with regard to theplane normal onto the active region that is larger than the first and / or second angle. Finally, a contact layer resides on the second doped layer and is at least partially extending on the regrown semiconductor layer. 0 The first and / or second angle are adjusted to optimize the quantum efficiency in the respective material system and layer stack. Those angles can be optimized independently of the third angle, which mainly affects the light extraction efficiency. 5 In some aspects, the first angle is taken with regard to the m-plane. Furthermore, the first and / or second angle form one of 0°, 11°, 15° and 28°. The second angle is generally larger and may correspond substantially to at least one of 39°, 47° and 58°. In this regard,0 the first and second angle for the optoelectronic component as wellas the method may vary over the overall surface and structure of the component. This variation is caused by the growth process or generally the processing. However, the above-mentioned value may represent the normal value, which is the intended angle with regard5 to the above-mentioned structures. Likewise, it is possible in someinstances, that side facets of at least one of the active region and the first doped layer are substantially parallel to one of an a-plane and an m-plane.0 Some aspects concern the regrown semiconductor layer. In someaspects, the regrown semiconductor layer extends at least partially on a surface of the layer stack adjacent to the contact layer. Consequently, material of the regrown semiconductor layer does not only cover the island of the component but also extends adjacent to5 it. In some aspects, a material composition of the regrownsemiconductor layer is the same as a material composition of the2023PF01132 - 13 -second doped layer. In such case, the regrown layer may be a part of the second doped layer. In some aspects, the side surfaces of the regrown semiconductor layer5 change their inclination. In some aspects, first portions of the sidesurfaces of the regrown semiconductor layer comprise the third angle and second portions of the side surfaces comprise a fourth angle with regard to the plane normal onto the active region, the fourth angle being larger than the first and / or second angle. 0 In some further aspects, the regrown semiconductor layer comprises different material compositions and / or dopant type or dopant concentrations. For example, the regrown semiconductor layer can comprise an undoped GaN layer, an undoped Alx(Ga)1-xN layer with an Al5 content of x between 0.0005 and 0.05, an undoped Iny(Ga)1-yN layerwith an In content of between 0.001 and 0.02, an Mg or Zn doped GaN or AlGaN material layer with a dopant concentration of 1e161 / cm³ to 8e18 1 / cm³ or combination of the above. In some aspects, the regrown semiconductor layer comprises one or more sub layers. 0 Some further aspects concern an optoelectronic array. Such arrays can be monolithically integrated and comprise a plurality of optoelectronic components as proposed herein. The array can be processed using the proposed method. In some aspects, the5 optoelectronic array comprises at least two optoelectronic componentsaccording to the proposed principle, which are connected together by a material bridge. In some aspect, the first doped layer of the at least two optoelectronic components comprise a common material portion as such material bridge, said common material portion0 laterally separating the semiconductor layer stacks with theirrespective side surfaces of the regrown semiconductor layers from each other. The distance between centres of two adjacent semiconductor layer stacks depends on a depth of the respective layer stacks and the third and / or fourth angle. 5 In some aspects, the common material portion is covered by material of the regrown semiconductor layer, a portion of which comprises a2023PF01132 - 14 -surface substantially parallel to the active layer of the at least two optoelectronic components. In some further aspects of the proposed optoelectronic array, the at5 least two optoelectronic components are arranged at central positionsof a virtual hexagonal grid, optionally said grid substantially parallel to m-planes of the layer stack or the first doped layer. In an alternative position, the at least two optoelectronic components are arranged in a chess like pattern, that is at central positions of0 a virtual grid of rows and columns, i.e. in the center of a “chessfield”. In such cases, the virtual grid substantially may be arranged parallel to a-planes of the layer stack. Some aspects concern the distance between the individual component in5 the array. The components should be placed at a minimum distance asto ensure that their respective regrown semiconductor layer do not overlap hereby reducing or even preventing an optical cross talk. In some aspects, the distance between the components’ centers is at least equal to the sum of its lateral diameter and two times the0 width of the side surfaces of the regrown semiconductor layermeasured adjacent to the common material portion times the tangent of at least one of the third and fourth angle. In other words, the minimum distance may be a function of the third and the fourth angle, and thus of the thickness of each component measured from the common5 material bridge to its top.Some other aspects concern the position and orientation of the optoelectronic components to each other. In some aspects, three adjacent optoelectronic components are arranged such that the edges0 of two adjacent side surfaces of adjacent components form anintersection with an angle of appr 120° in between. In some other aspects, an edge of a regrown semiconductor layer on a side facet of each optoelectronic component intersects with a portion of the regrown layer on the surface portion of the first doped layer aligned5 substantially with the 1210 direction or its equivalences thereof.In a further option, intersections of the regrown layer on the surface portion of the first doped layer with the regrown2023PF01132 - 15 -semiconductor layers of two adjacent islands facing each other are substantially parallel. In some alternative aspects, following a chess-like grid pattern,5 edges of the regrown semiconductor layer on the side facets of twoadjacent optoelectronic components are facing each other. Likewise, intersections of the regrown layer with the surface portion of the first doped layer of two adjacent optoelectronic components may form an angle of appr. 120° in between in some aspects. 0 SHORT DESCRIPTION OF THE DRAWINGS Further aspects and embodiments in accordance with the proposed principle will become apparent in relation to the various embodiments and examples described in detail in connection with the accompanying5 drawings in whichFigures 1A to 1E show a first embodiment of a method for processing optoelectronic devices in accordance with some aspects of the proposed principle; 0 Figures 2A to 2C illustrate a second embodiment of a method for processing optoelectronic devices in accordance with some aspects of the proposed principle;5 Figures 3A to 3C show a third embodiment of a method for processingoptoelectronic devices in accordance with some aspects of the proposed principle; Figures 4A and 4B illustrate some further method steps of a method0 for processing optoelectronic devices in accordance with some aspectsof the proposed principle; Figure 5 is an electron microscope picture of an arrangement of layer stacks for optoelectronic components in a hexagonal grid in5 accordance with some aspects of the proposed principle;2023PF01132 - 16 -Figure 6 is an electron microscope picture of an arrangement of optoelectronic components in a hexagonal grid in accordance with some aspects of the proposed principle;5 Figure 7 shows a top view of an arrangement of optoelectroniccomponents in a hexagonal grid in an array in accordance with some aspects of the proposed principle; Figure 8 is an electron microscope picture of an arrangement of0 optoelectronic components in a chess like grid in accordance withsome aspects of the proposed principle; Figure 9 shows a top view of an arrangement of optoelectronic components in a chess-like grid in an array in accordance with some5 aspects of the proposed principle;Figures 10A to 10C show embodiments of optoelectronic components in a side view having different surface portions of the regrowth layer in accordance with some aspects of the proposed principle; 0 Figure 11 illustrates crystallographic planes of GaN material to support some aspects of the proposed principle. DETAILED DESCRIPTION5 The following embodiments and examples disclose various aspects andtheir combinations according to the proposed principle. The embodiments and examples are not always to scale. Likewise, different elements can be displayed enlarged or reduced in size to emphasize individual aspects. It goes without saying that the individual0 aspects of the embodiments and examples shown in the figures can becombined with each other without further ado, without this contradicting the principle according to the invention. Some aspects show a regular structure or form. It should be noted that in practice slight differences and deviations from the ideal form may occur5 without, however, contradicting the inventive idea.2023PF01132 - 17 -In addition, the individual figures and aspects are not necessarily shown in the correct size, nor do the proportions between individual elements have to be essentially correct. Some aspects are highlighted by showing them enlarged. However, terms such as "above", “over”,5 "below", "under" "larger", "smaller" and the like are correctlyrepresented with regard to the elements in the figures. So it is possible to deduce such relations between the elements based on the figures.0 Figures 1A) to 1E) illustrate some steps of an embodiment for amethod of processing a plurality of optoelectronic components in accordance with the proposed principle. The present embodiment is related to a nitride-based material system.5 Material systems based on a nitride provide various opportunities forchoosing or adjusting the actual material composition in the respective layer stack. The material composition affects the band gap, and different band gaps cause carrier recombination under light emission of different colors. Likewise, the crystal lattice various0 slightly with different material compositions of nitride-basedmaterials. Still, both parameters can be adjusted such that various colors within the visible spectrum are achievable by processing nitride-based material systems with different material compositions, doping type, and doping concentrations. Further design factors5 optimize the internal quantum efficiency of such devices. Combiningthe various design choices with the proposed principle enables an improvement of the internal quantum efficiency and the light extraction efficiency separately and independently of each other. Nitride based material systems include gallium nitride GaN, indium0 gallium nitride InGaN, aluminum gallium nitride AlGaN, as well asaluminum indium gallium nitride AlInGaN as a Quaternary material system. The aluminum and indium content can be varied and adjusted to the perspective needs. An increase of the aluminum content usually increases the band gap and vice versa. An increasing indium content5 reduces the band gap of the material composition, shifting the lightemission towards the red portion of the visible spectrum, while also changing the crystal lattice.2023PF01132 - 18 -Figure 1A) illustrates the result of a first epitaxial deposition process, in which a gallium nitride buffer layer applied onto a growth substrate 10 is provided. The top surface of the gallium5 nitride buffer and the growth substrate 10 is processed, for example,by first depositing a gallium nitride buffer layer on the growth substrate. The growth substrate can also include gallium nitride GaN, but also Sapphire or any other suitable substrate, which preferable comprises a crystal lattice similar to the one of GaN or the material0 composition of the layer stack to be processed. This avoids a higherdefect density due to lattice mismatch. The buffer layer applied on the growth substrate 10 is usually undoped and provides a smooth and defect reduced surface for the subsequent layers of the layer stack 1. 5 The various layers of layer stack 1 are also deposited epitaxially, for example by a vapor deposition process known in the art. The layer stack includes layers of different composition, different doping concentration and the like to achieve specific functionalities. In0 the present example, layer stack 1 is epitaxially deposited by firstdepositing an n-doped layer 11 on the growth substrate 10. N-doped layer 11 comprises a plurality of sub layers, including a first sub layer adjacent to the buffer layer with an increased dopant concentration for current spreading into the subsequent layers.5 Consequently, this sub layer (not shown) acts as a contact layer fora metal or a transparent conductive oxide layer. Another, preferable undoped sub layer being part of the first doped layer 11 is epitaxially deposited directly adjacent to the active region 12 and acts as a cladding layer preventing an undesired dopant diffusion0 into the active region 12.Active region 12 comprises a plurality of barrier and quantum well layers, whereas the quantum well layers include a smaller band gap than the surrounding barrier layers. For example, the barrier layers5 may contain a higher aluminum content or a reduced indium content,while the quantum well layers comprise a reduced aluminum content in comparison to the barrier layers or an increased indium content.2023PF01132 - 19 -Generally, the various layers of the multi-quantum well structure of the active region 12 can be processed by adjusting the respective material composition, - for example in the gas vapor, during the epitaxial deposition process. The thickness of each barrier and5 quantum well layer may range from a few nanometers to approximatelyseveral tens of nm, while the number of the various quantum well layers may range from a few quantum well layers to several tens of quantum well layers.0 Another undoped cladding layer (not shown) is deposited on top ofactive region 12. The cladding layer is a part of the second doped layer 13. A plurality of p-doped sub layers is epitaxially deposited on top of the undoped cladding layer, providing a similar functionality as the n-doped layer 11. In addition, a specific5 electron blocking layer can be applied directly adjacent to thecladding layer, acting as a charge carrier barrier layer preventing electrons from reaching the p-doped sub layers of the second doped layer 13. The resulting structure depicted in Figure 1A) may include a plurality of further layers, different material compositions,0 dopant concentrations and the like depending on the desired designchoice, the application and the wavelengths to be emitted. Generally, the stack 1 is applied on wafer level using known techniques. A mask layer material is deposited in a subsequent step, and5 subsequently structured to cover a plurality of regions of the p-doped layer 13. The covered regions will subsequently form islands of the layer stack (subsequently referred to as island) acting as a seed for the optoelectronic components to be processed.0 For this purpose, a mesa structuring process is conducted on theexposed material sections of doped layer 13 around the covered portions. The mesa structuring process may include one or more etching steps to form recesses 21, as illustrated in Figure 1B. The mesa structuring process exposes sidewall portions 30 of the active5 region 12 referred to as side facets, as well as side facets 31 ofthe n-doped layer 11. Furthermore, surface portions 32 of the n-doped layer 11 between two adjacent islands are exposed.2023PF01132 - 20 -As illustrated in Figure 1B, a material bridge 11’ of unetched portions of n-doped layer material bridges the recesses 21 and connects the various islands together. This material bridge can5 subsequently form a common layer of the optoelectronic components,for example, in an optoelectronic array. The distance between the island create after the mesa structuring process is given by the mask layer. This distance as well as the depth is relevant for the subsequent process steps, as a distance between the islands should0 not fall short of a minimum value, which in turn also depends on theangle of the surface of the regrowth layer. The angle α of the exposed side facets 30 and 31 is measured in relation to a plane normal to the growth plane. Its value is adjusted5 depending on the etching process, the etching material, as well asfurther design parameters. The angle α usually corresponds to the orientation of certain planes of the crystal structure of the material of layer stack 1. In other words, the etching process is not random, but usually follows one of those planes of the crystal0 structure. Based on the material, i.e. whether it is polar or not,and the etching parameters, one can select or at least bias the etching process to follow a certain plane. Figure 11 in this regard illustrates some possible planes for5 nitride-based material systems, as well as possible angles and itscorresponding planes during the structuring and etching process. Figure 11(a)illustrates the c-plane in form of a hexagonal shape. The c-plane is used in the present example as the plane, on which the0 layer stack is grown. When providing the structured mask layer 20, itis beneficial to align the edges of the structured mask layer along the crystal orientations, as shown in Figure 11. This will simplify the subsequent etching process, as the etchant favors material removal along those planes and directions.5 For example, a mask layer aligns along the a-plane corpses arectangular shape, shown in Figure 11(b), while a mask layer with a hexagonal shape should be aligned following the m-plane, that is the2023PF01132 - 21 -1210 direction or its equivalences, see figure 11(c) for suchembodiment. During the etching process, the material is preferably removed along5 the hexagonal structure and the 1210 direction or its equivalencesHowever, the etching parameter also enable to adjust the angle α, that is inducing an inclination. In some aspects, the etching parameters are adjusted such that the angle α follows the s6-plane as shown in Figure 11(i), indicating an angle α between the s6-plane and0 the m plane of about 15°. The m-plane is normal to the c-plane.Another possible angle is the s5 plane with a 28° inclination or the (2023)-plane (not shown in figure 11) with a tilt angle α of 39°. However, usually, smaller angles between 0° and 30° are preferred for the exposed side facets. 5 Still, the combination of the structured mask layer with the etching parameters can adjust and select certain planes to be exposed for the side facets of the active region and the first doped layers. Tn this regard, it is possible that the angle α changes, depending on the0 material of the side facet. However, the hexagonal structure innitride-based material systems is usually preferred, thereby resulting often in a hexagonal structure along the m-planes and the respective 1210 direction at the intersection between the lowestportion of expose side facets 31 and the parallel exposed top surface5 34 of the material bridge 11’.After optionally annealing the exposed side facets, a nitride-based material system is applied as a re-growth semiconductor layer 40 in a subsequent step. The material of regrowth layer 40 comprises a band0 gap that is larger than the band gap of the active region 12 and inparticularly its quantum well layers within said region. The material is either undoped or slightly p-doped in the given example. The dopant is Mg or Zn with a concentration of less than 1e181 / cm³. It has been found that Mg as dopants for GaN or AlGaN material with5 small Al contents, only a small portion of the dopants (i.e. about 1%to 5%) is electrically active, while the other portion generates deep states in the band gap. Hence, electric current through the2023PF01132 - 22 -artificially generated pn-junction between material 40 and the material of n-doped layer 11 and 11’ is not significant. The semiconductor layer 40 is epitaxially deposited and covers the5 exposed side facets as well as the top surface of the materialbridges 11’. The epitaxial deposition process along the side facets will generate a growth in a certain direction, whereas the angle β can be varied and adjusted to specific values by the growth parameters. The angle β is at least equal or larger than the0 corresponding angle α and may change during the deposition process,as illustrated further below. As illustrated in Figure 1C), the epitaxially deposited material of the regrowth layer 40 covers the exposed side facets 30 of active5 region 12, as well as the exposed side facets of the n-doped layer 11and the top surface of the material bridge. The distance between two adjacent islands is adjusted in this example to a value in which the inclined sidewalls 41 of the regrowth layer do not overlap or meet each other. Rather, a bottom portion 42 of the regrowth layer is a0 substantially parallel to the active region 12 in between twoadjacent islands. After the regrowth process is finished, the mask layer material 20 is removed, resulting in the structure depicted in Figure 1D). In a5 subsequent step shown in Figure 1E), a contact layer material 50 isdeposited extending from the top surface of p-doped layer 13 along the sidewalls 41 of the regrowth layer 40. The regrowth layer 40 is either may be p-doped, although only a small portion of the dopant affect the electrical characteristics. It may also be undoped. In any0 case, the regrowth layer 40 comprises a relatively high ohmicresistance along the side facets and the bottom of recess 21. Consequently, the artificially created pn-junction between the n- doped layer 11 and the material of regrowth layer 40 is not significant and does only slightly affect the overall quantum5 efficiency. This property can be further reduced by adjusting thematerial composition of the regrowth layer, as outline further below, using sub layers of different material compositions. However, the2023PF01132 - 23 -light extraction efficiency is significantly improved due to the larger angle β, while maintaining a high internal quantum efficiency largely affected by the handling of the exposed side facet 30.5 The contact material 50 on top of the doped layer 13 as well as onthe side facets 41 of the regrowth layer 40 may comprise a reflective metal, a DBR structure or a combination thereof. This will cause light being emitted towards the contact material 50 being reflected towards the main emission surface opposite the active region. A small0 etching process is performed, opening the contact material betweenthe island forming the recess 43 to separate the various optoelectronic components electrically from each other or reduce optical crosstalk. In this particular example illustrated in Figure 1E), the recess also cuts through the re-growth layer in the recess,5 thereby improving the optical and electrical separation of theindividual components. The proposed method for processing a plurality of optoelectronic components can be varied and adjusted in accordance with the design0 choices and needs for a respective application. For example, it ispossible to additionally structure the mask layer after the mesa structuring process to enable an application of the regrowth layer not only on the exposed side facets of active region 12 and an n- doped layer 11, but also on the top of the p-doped layer 13. 5 In this regard, the p-doped layer 13 may not be necessary in cases, in which the regrowth layer is applied directly on the active region 12 or on a cladding layer in between. In such cases the p-dope regrowth layer act as second doped layer proving a carrier transport0 and injection into the active region.Figures 2A) to 2C) illustrate another embodiment in accordance with the proposed principle. In Figure 2A) the mesa etching process has been conducted exposing facets 30 and 31 of the active region 12 and5 the n-doped layer 11, respectively. The material of mask layer 20 isthen further structured, exposing top portions of layer 13 adjacent to the mask layer 20. The location of the remaining mask layer2023PF01132 - 24 -material is later used to provide a recess and give access to the top of p-doped layer 13 for applying a contact thereto. A nitride-based material system having a band gap larger than the5 band gap of active region 12 is epitaxially deposited in a subsequentstep on top of the doped layer 13, as well as the exposed side facets 30 and 31 and the top surface of material bridge 11. The nitride base material system comprises for example GaN with a small Al content in the range of up to 2%, i.e. Al0.02Ga0.98N. This small content is large0 enough to generate a potential barrier on the exposed side facets ofactive region 12, but does not adversely affect the growth parameter or the angle of the regrowth layer. The epitaxially deposited material forms a plurality of sub layers, whereas the different sub layer of regrowth layer 40 may comprise different material5 compositions or dopant concentrations. For example, a first sub layerdirectly adjacent to the exposed side facets may comprise a higher aluminum content, thereby increasing the overall band gap of the sub layer compared to the band gap of the active region. Furthermore, these sub layers may be undoped only comprise a small p-dopant0 concentration, increasing the overall resistivity and avoidingforming a large artificial pn-junction around the respective layer stacks. The resulting structure is illustrated in Figure 2B). The mask layer material 20 is removed in a subsequent step, exposing5 the top surface of p-doped layer 13 as shown in Figure 2C. A contactmaterial 50 is then applied into the recess 52 as well as on the side surfaces thereof. In some aspects, another mask layer can be structured and applied on the top surface, thereby covering the portion bottom 42 of the regrowth layer in the recess, preventing the0 contact material 50 from extending onto said portion in the recessbetween two adjacent islands. Similar as in the previous embodiment, the various optoelectronic components are separated by etching through the contact layer material and the portions of the regrowth layer in the recess.5 In the two embodiments illustrated in Figures 1A to 2C, the exposedside facets of the layer stack are inclined with angle α due to the parameters of the mesa structuring process. However, another option2023PF01132 - 25 -lies in structuring the side facets such that they follow one of the m-planes or a-plane as depicted in Figure 11(b) and 11(c). This is achieved by first providing a dry etching process similar to the previous embodiments, followed by a subsequent wet mesa etching5 process using KOH or H3PO4 as etchants. Particularly KOH is a highlyselective etchant to etch particularly the semipolar facets, that is until the m-plane is reached. It does not etch the c-plane, too. This wet etching process results in a self-alignment and self-limitation, forming substantially vertical exposed side facets along the m-plane. 0 Figure 3A) illustrates the result of such combination during the mesa structuring process. The vertical exposed side facets are subsequently overgrown by epitaxially depositing the re-growth material thereupon. The exposed vertical side facets 34 are covered5 by the regrown material, which in itself grows not equally butforming an angle β adjustable by the respective growth parameters. In a subsequent step, the mask layer material 20 is removed, resulting in the structure depicted in Figure 3B). Finally, similar to the previous embodiments, contact layer material 50 is applied on the0 exposed portion of the doped layer 13 as well as on the side facetsof the material of regrowth layer 40. Figures 4A) and 4B) illustrate two further embodiments of processing such optoelectronic components forming optoelectronic arrays. In the5 respective embodiments, the growth substrate 10 is removed by firstre-bonding the plurality of optoelectronic components to a temporary wafer (not shown) to get access to the growth substrate 10. The growth substrate 10 together with a possible buffer layer material is removed. The exposed surface 100 of the n-doped layer 11 forms the0 main emission surface 101 of the optoelectronic component. It issubsequently roughened or otherwise structured 100 to improve the light extraction efficiency. In some instances, an ITO or another layer is deposited to match refractive indices with other structures. µ-lenses or also a converter material layer can be applied if5 desired.2023PF01132 - 26 -The plurality of optoelectronic components is then attached to a plurality of contact blocks 55 connected to a carrier substrate 60, which includes various kinds of circuit driver, control circuitry and the like. This process can also be reversed, such that the component5 is attached to the carrier substrate 60 first and then the growthsubstrate is removed. The space in the respective recesses, as illustrated in Figure 4A) and 4B) is usually filled with a dielectric material prior to the re-bonding process to form an even surface with the contact material 50 for the p-doped layer 13 exposed. The0 contacts 55 electrically connect the driver circuitry in carriersubstrate 60 to the p-doped layer 13 of the individual optoelectronic components. The previously applied mesa structuring process is conducted to have a small material bridge 11’ remaining between adjacent optoelectronic components, thus forming a common electrical5 contact area. An ITO layer (not shown herein) can be applied on theexposed surface forming the main emission surface or portions thereof to further enhance the conductivity. However, due to the thickness of the small material bridge, optical crosstalk can be avoided.0 Figures 5 and 6 show EM pictures of the respective islands after themesa structuring process and after the re-growth deposition process. In Figure 5, several islands are shown after the mesa structuring process, exposing a surface of the material bridge 11’ between the5 various islands. The mask layer material 20 has been removed forillustration purposes, leaving the top surface f p-doped layer 13 exposed. When viewed from the top, the edges of each p-doped layer of the individual islands forms a hexagonal shape. The edges are aligned with the 1210 direction and its equivalences. The mesa structuring0 process results in an angle α, which is substantially given by theetching parameters along the 1210 direction corresponding to the m-plane. The conducted etching process emphasizes and follows the hexagonal structure forming exposed side facets 30 of the active region as well as 31 of the first doped layer. The intersection on5 the lower portion of the exposed side facets 31 with the top surfaceof the material bridge 11 also follows the 1210 direction and formsa hexagonal shape when viewed from the top.2023PF01132 - 27 -After the epitaxial deposition process of the re-growth material with a higher band gap than the active region of the exposed side facets, the hexagonal shape and the side facets are becoming more apparent.5 The result of the epitaxial deposition process on the islands offigure 5 is shown in Figure 6. The deposition process and the application of material of the regrowth layer is conducted in such way, that two opposing facets 41 of adjacent optoelectronic components form an intersection on the top surface of material bridge0 11’.Two facets of each optoelectronic components on the different planes form an edge in between. As apparent in Figure 6, the edges of the adjacent optoelectronic components are meeting substantially at one5 point, whereas the intersections of the opposing facets form an angleof 120° in between at such point. This structure follows the underlying hexagonal crystallographic c-plane allowing highly dense placement of optoelectronic components with an adjustable angle β for optimized light extraction efficiency. 0 Figure 7 in this regard illustrates a top view of that structure. The structure comprises a hexagonal grid structure 400 with the respective layer stacks or islands (presented by its top surface 13) being positioned in the center of the hexagonal grid 400. 5 In the present example in Figure 7, the surface of side facets 30 and 31 illustrated by the dashed line around the top surface of doped layer 13, comprise, when viewed from top a hexagonal shape. This is due to the preference of the GaN material to grow along the 12100 direction. It has been found in this regard that even when the masklayer is misaligned or comprises a non-hexagonal shape, the mesa structuring process and a subsequent annealing may likely result in exposed surfaces that self-align and eventually follow the direction corresponding to the m-plane and its equivalences. The side facets 415 of the regrowth layer extent along the 1210 direction having alarger angle compared to the exposed side facets 30 and 31. As shown in figure 7 two side facets of adjacent islands are opposing each2023PF01132 - 28 -other and their intersections with the surface 11’ run parallel to each other. Further, when looking at the intersections of three adjacent islands, the intersections from an 120° angle in between them. 5 The distance between two centers of the island is also referred to as pixel pitch. The pixel pitch should not fall short of a minimum distance. This minimum distance is a function of the lateral size of the islands, i.e. its diameter, the height of the respective islands0 (corresponding to the thickness of the respective layer that has beenetched) and the angle β. It is given by the following approximation: Pitch => Diameter + 2 * Depth * tan(β)5 If the pixel pitch is smaller than the value derived by the above-mentioned approximation and the angle β shall be achieved, the growth material of adjacent island will overlap, thereby increasing the risk of crosstalk.0 In the present example, the distance between two adjacent layerstacks with their respective the doped layers 13 are larger than the required minimum distance defined by the lateral dimension of the layer stack given by the dashed line of exposed side facets 30 and 31 and the angle β as well as the recess depth in between. Consequently,5 two opposing facets 41 of the regrowth layer still separated by asmall distance and a portion of the top surface of the material bridge 11’. However, as seen from the previous picture in figure 6, the surface of layer 11’ can fully be covered by material 41 without overlap, that is two opposing side surface of regrowth layer 41 are0 directly adjacent to each other. This configuration with a hexagonalshape following the above direction allows the densest configuration of optoelectronic devices with a given, jet adjustable angle β. Figure 8 illustrates another arrangement of the layer stacks in a5 chess like grid pattern. The islands are formed by the mesastructuring process at centers of a chess pattern, such that they are aligned in rows and columns with each other. Still, due to the2023PF01132 - 29 -structuring process, the islands have side facets that follow the 1210 direction and its equivalences. It comprises a hexagonal shapewhen viewed from the top.5 The islands are then overgrown by epitaxially depositing a layer witha band gap higher than the band gap of the active region. Due to the positions and orientation of the islands towards each other, the structure has a broken symmetry. In one direction of each island, in Figure 8 from left to right, the edges formed by two adjacent side0 facets of the regrowth layer of adjacent islands are facing eachother. In the other direction, two side facets of adjacent islands are opposing each other. In the structure of Figure 8, the material of the regrowth layer is partially overlapping each other. This is due to the reduced distance between the islands. 5 Figure 9 illustrates a similar embodiment viewing it from top. The individual islands are centered in a chess like grid or pattern. The grid is aligned to the a-plane or the 1100 direction and itsequivalences, although each of the islands of the mesa structured0 layer stack comprises a hexagonal pattern aligned to the m-planes.The top surface of p-doped layer 13 is exposed, the first dashed line surrounding the top surface of layer 13 corresponds to the intersection of the exposed side facets of the layer stack with the top surface of material of layer 11’. The regrowth material is5 epitaxially deposited on top the of the exposed side facets of thelayer stack forming the side surface 41 thereof. The surface of each optoelectronic component also resembles a hexagonal structure. As shown, the orientation and positioning of the islands of semiconductor layer stack in the grid causes an asymmetry in the x-0 and y-directions. Two adjacent side surfaces of each optoelectroniccomponent form an edge, which in the projection shown in Figure 9 comprise an angle of 120° in between. As a result, edges of two adjacent optoelectronic components are facing each other along the x- direction. In other words, along the x-direction, the edges of two5 adjacent optoelectronic components are closest to each other. As aresult, the intersections of two adjacent optoelectronic components form an angle of 120°.2023PF01132 - 30 -In the y-direction, the situation is different and here the intersections of two adjacent optoelectronic components are substantially aligned and parallel to each other. Consequently, the space between the adjacent component is different in the various5 directions. It is not possible in this configuration to cover thesurface of layer 11’ with material 41 of a regrowth layer without overlapping the regrowth layers. Rather, a small surface portion of uncovered material of layer 11’ will remain in the area between four adjacent optoelectronic components. 0 The various growth parameters as well as the mesa structuring process provide a higher flexibility as to a selection and adjustment of the respective growth angle β as well as the etching angle α during the mesa structuring process. 5 Figures 10A) to 10C) illustrate several embodiments of a component in a side view, in which different growth angles for the regrowth layers 40 are achieved by varying the growth parameter during the epitaxial deposition process. Figure 10A) shows a first embodiment, in which0 the layer stack having a first doped layer 11, active region 12 andsecond doped layer 11 deposited on each other comprises vertical side facets. The emission side 101 is the respective bottom side of the embodiments. For simplicity purposes, no specific shape of the layer stack is indicated. It is however understood that the layer stack may5 comprise a hexagonal shape or a rectangular shape when looking fromtop. The exposed vertical side facets of the layer stack are covered by a potentially depositing material of the growth layer using first0 deposition parameters. This results in regrowing material with afirst angle β2as depicted herein. After a certain deposition period, the deposition parameters are changed, resulting in different growth speeds and particularly in a different growth angle β1. Particularly, the angle is reduced from β2to β1. The resulting structure is5 depicted in Figure 10A) in a side view, whereas the transition fromβ2to β1is at a level slightly below the active region 12. The two different angles β cause two portions of side facets with regrowth2023PF01132 - 31 -material, namely portion 411 with a steeper inclination and portion 412 with a shallow inclination. In the given example, the angle β2is at appr. 47°, measured to a plane normal to the active region, while the angle is appr 28°. The two portions and the level between them is5 adjustable depending on the growth parameter and can greatlyinfluence the light extraction efficiency and other light emission characteristics. Figure 10B) illustrates another example, in which the change from0 angle β2 to β1 occurs at a position which is on the level of the p-doped layer 13 and slightly above the active region 12 when viewed from the main emission side. In contrast to the previous embodiment, the value of angles β2and β1are reversed, so angle β1is approximately 47°, while angle β2is only 28°. 5 Figure 10C) illustrates a further embodiment, in which already inclined exposed side facets having angle α are epitaxially covered by a regrowth material. The angle α lies at appr. 15°. The parameters for the deposition process of the regrowth material are adjusted and0 changed such that regrowth surface 411 close to the top portion ofthe layer stack forms the angle β1of about 58°. The second regrowth surface portion 412 adjacent to the emission surface 101 comprises a smaller angle β2of about 39°. The edge between the first and second portions of the regrowth layer surface is slightly below the active5 region and thus closer to the emission surface 101.The various angles β and α as well as the position of the transition between the third angle β1and the fourth angle β2(or even more angles) can be adjusted by the growth parameters. It may be suitable,0 in some aspects, to have a first surface angle of regrowth materialcovering the exposed portions of the doped layer 13 and the active region 12 and a second angle covering most of the exposed portions of first doped layer 11. The surfaces of the regrowth layer are covered by a reflective material which reflects the light being generated in5 the active region 12 towards the main emission surface 101.2023PF01132 - 32 -The proposed principle is applicable in a variety of application and allows adjusting the quantum efficiency that is the efficiency for generating light in active region 12 and the light extraction efficiency independently of each other. 5

[0002] 2023PF01132 - 33 -LIST OF REFERENCES layer stack10 growth substrate5 11 first doped layer11’ material bridge 12 active region13 second doped layer20 mask layer0 30, 31 side facets32 surface portion34 vertical side facets40 regrowth material41 side surface5 42 bottom portion43 recess50 contact material52 recess55 contact0 60 carrier substrate100 surface structure101 emission surface400 hexagonal grid411, 412 portions of side surface5 α1, α2 1st angle, 2nd angleβ1, β2 3rd, 4th angle

Claims

2023PF01132 - 34 -CLAIMS 1. Method for processing a plurality of optoelectronic components,comprising the steps of:5 - Providing a growth substrate;- Epitaxially depositing a semiconductor layer stack based on anitride material system, said layer stack comprising a first doped layer adjacent to the growth substrate and an active region on top of the first doped layer, wherein the active0 region comprises a band gap that is at least partially smallerthan a band gap of at least portions of the first doped layer; -Providing a structured mask on top of the semiconductor layerstack, wherein the structured mask covers at least two portions of the active region laterally displaced to each other and5 wherein optionally at least portions of edges of the structuredmask are aligned to a crystallographic plane, in particular one of the a-plane and m-plane; -Conducting a mesa structuring process to form islands exposingfor each island0 o side facets of the active region and the first dopedlayer and a surface portion of the first doped layer substantially parallel to the active region adjacent to each island, owherein the side facets of the active region form a first5 angle with regard to a plane normal onto the activeregion; and owherein the side facets of the first doped layer form asecond angle with regard to the plane normal onto the active region;0 - Epitaxially regrowing on each island a semiconductor layerbased on a nitride material system at least on side facets of the active region and the first doped layer and a surface portion of the first doped layer substantially parallel to the active region, whereby side surfaces of the regrown5 semiconductor layer comprise a third angle with regard to theplane normal onto the active region that is larger than the first and / or second angle.2023PF01132 - 35 -2. Method according to claim 1, wherein the plane is the m-plane andwherein optionally the first and / or second angle form one of 0°, 11°, 15° and 28°.5 3. Method according to claim 1 or 2, wherein the third angle is atleast one of 39°, 47° and 58°.

4. Method according to any of the preceding claims, wherein the stepof providing a structured mask comprises the step of0 - Depositing a mask layer material;- Structuring the mask layer material such that a distance between centers of the at least two portions covered by the mask layer material comprises at least the sum of a diameter of the mask portion and a value based on a depth of a recess separating two5 adjacent islands and the tangent of the third angle.

5. Method according to any of the preceding claims, wherein the stepof conducting a mesa structuring process to form islands, when viewed from the top, forms a hexagonal island structure at an0 intersection between side facets of the first doped layer and thesurface portion of the first doped layer, whereas said interface is substantially parallel to the 1210 direction or itsequivalences thereof.5 6. Method according to any of the preceding claims, wherein- the islands are arranged at central positions of a virtual hexagonal grid, optionally said grid substantially parallel to m- planes of the layer stack; or - the islands are arranged at central positions of a virtual gird0 of rows and columns, optionally said grid substantially parallelto a-planes of the layer stack.

7. Method according to any of the preceding claims, wherein the stepof conducting a mesa structuring process to form islands comprises5 the step of:- Etching the active region and the first doped layer to a depth between a top surface of the layer stack and the surface portion2023PF01132 - 36 -of the first doped layer proportional to 1 over the tangent of the third angle.

8. Method according to any of the preceding claims, wherein the step5 of epitaxially regrowing a semiconductor layer on each islandcomprises the step of: - Epitaxially regrowing a semiconductor layer on side facets of the active region and the first doped layer and the surface portion of the first doped layer such that edges of the regrown0 semiconductor layers of three adjacent islands form anintersection with an angle of appr 120° in between; and / or - Epitaxially regrowing a semiconductor layer on side facets of the active region and the first doped layer and the surface portion of the first doped layer such that an intersection of a5 regrown semiconductor layer on a side facet intersects with aportion of the regrown layer on the surface portion of the first doped layer substantially parallel to the 1210 direction or itsequivalences thereof; and / or - Epitaxially regrowing a semiconductor layer on side facets of0 the active region and the first doped layer and the surfaceportion of the first doped layer such that intersections of regrown semiconductor layers on side facets of two adjacent islands with the regrown layer on the surface portion of the first doped layer are substantially parallel; and / or5 - Epitaxially regrowing a semiconductor layer on side facets ofthe active region and the first doped layer and the surface portion of the first doped layer such that a portion of the regrown layer on the surface portion is substantially parallel to the active region of the adjacent islands. 0 9. Method according to any of claims 1 to 8, wherein the step ofepitaxially regrowing a semiconductor layer on each island comprises the step of: - Epitaxially regrowing a semiconductor layer on side facets of5 the active region and the first doped layer and the surfaceportion of the first doped layer such that an edge between two adjacent surface regions of a regrown semiconductor layer of an2023PF01132 - 37 -island is facing an edge between two adjacent surface regions of a regrown semiconductor layer of an adjacent island; and / or - Epitaxially regrowing a semiconductor layer on side facets of the active region and the first doped layer and the surface5 portion of the first doped layer such that intersections ofregrown semiconductor layers on a side facets of two adjacent islands with the regrown layer on the surface portion of the first doped layer comprise an angle of appr. 120° in between; - Epitaxially regrowing a semiconductor layer on side facets of0 the active region and the first doped layer and the surfaceportion of the first doped layer such that a portion of the regrown layer on the surface portion is substantially parallel to the active region of the adjacent islands.5 10.Method according to any of the preceding claims, wherein the stepof epitaxially regrowing a semiconductor layer on each island comprises: - Varying conditions during regrowing a semiconductor layer on each island to form first portions of the side surfaces comprising0 the third angle and second portions of the side surfacescomprising a fourth angle with regard to the plane normal onto the active region, the fourth angle being larger than the first and / or second angle.5 11.Method according to any of the preceding claims, wherein the stepof epitaxially regrowing a semiconductor layer on each island comprises the steps of -Structuring the mask layer to expose top surface portions ofthe semiconductor layer stack;0 - Epitaxially regrowing the semiconductor layer on the exposedportions. 12.Method according to any of the preceding claims, wherein the step of conducting a mesa structuring process comprises:5 - Conducting a wet etching process, in particular using KOH orH3PO4, to form side facets of the active region and / or the first doped layer that are substantially vertical onto the surface2023PF01132 - 38 -portion of the first doped layer substantially parallel to the active region adjacent to each island. 13.Method according to any of the preceding claims, wherein the step5 of epitaxially depositing a semiconductor layer stack comprisesthe step of: -Epitaxially depositing a second doped layer on the activeregion, wherein the second doped layer comprises a doping type different from the doping type of the first doped layer. 0 14.Method according to any of the preceding claims, wherein -the first doped layer of the semiconductor layer stackcomprises an, in particular undoped, cladding layer adjacent to the active region. 5 15.Method according to any of the preceding claims, wherein the regrown semiconductor layer comprises at least one of: -an undoped GaN layer;- an undoped Alx(Ga)1-xN layer with an Al content of x between0 0.0005 and 0.05;- an undoped Iny(Ga)1-yN layer with an In content of between 0.001and 0.02; -an Mg or Zn doped GaN or AlGaN material layer with a dopantconcentration between 1e161 / cm³ and 8e181 / cm³;5 - combinations of the above.16.Method according to any of the preceding claims, further comprising the step of: -Removing the mask layer on top of the semiconductor layer0 - Applying a contact layer on the exposed portions of the top andoptionally on portions of the regrown semiconductor layer; -Optionally separating islands from each other by etching thoughthe contact layer between two opposing side surfaces of the regrown layer. 5 17.Optoelectronic component, comprising: -A semiconductor layer stack epitaxially deposited in adirection perpendicular along the c-plane, the semiconductor2023PF01132 - 39 -layer stack comprising a first doped layer and an active region adjacent to the first doped layer and a second doped layer adjacent to the active region, wherein the active region comprises a band gap that is at least partially smaller than a5 band gap of at least portions of the first doped layer;- Mesa structured side facets of the active region and the firstdoped layer wherein othe side facets of the active region form a first anglewith regard to a plane normal to the active region; and0 o the side facets of the first doped layer form a secondangle with regard to the plane normal onto the active region; -a regrown semiconductor layer based on a nitride materialsystem at least on side facets of the active region and the5 first doped layer and a surface portion of the first dopedlayer substantially parallel to the active region; -wherein a band gap of the regrown semiconductor layer is largerthan a band gap of at least portions of the active region; and -wherein side surfaces of the regrown semiconductor layer form a0 third angle with regard to the plane normal onto the activeregion that is larger than the first and / or second angle; -a contact layer deposited on the second doped layer and atleast partially extending on the regrown semiconductor layer.5 18.Optoelectronic component according to claim 17, wherein- the plane is the m-plane and wherein optionally the firstand / or second angle form one of 0°, 11°, 15° and 28°; and / or -the third angle is at least one of 39°, 47° and 58°.0 19.Optoelectronic component according to any of claims 17 to 18,wherein side facets of at least one of the active region and the first doped layer are substantially parallel to one of an a-plane and a m-plane.5 20.Optoelectronic component according to any of claims 17 to 19,wherein2023PF01132 - 40 -- the regrown semiconductor layer extends at least partially on a surface of the layer stack adjacent to the contact layer; and / or - a material composition of the regrown semiconductor layer is the same as a material composition of the second doped layer. 5 21.Optoelectronic component according to any of claims 17 to 20, wherein first portions of side surfaces of the regrown semiconductor layer comprise the third angle and second portions of the side surfaces comprise a fourth angle with regard to the0 plane normal onto the active region, the fourth angle being largerthan the first and / or second angle. 22.Optoelectronic component according to any of claims 17 to 21, wherein5 - the first doped layer of the semiconductor layer stackcomprises an, in particular undoped, cladding layer adjacent to the active region; and / or -the second doped layer of the semiconductor layer stackcomprises an, in particular undoped, cladding layer adjacent to0 the active region;- the second doped layer of the semiconductor layer stackcomprises an electron blocking layer base on an AlGaN composition adjacent to the active region.5 23.Optoelectronic component according to any of claims 17 to 21,wherein the regrown semiconductor layer comprises at least one of: -an undoped GaN layer;- an undoped Alx(Ga)1-xN layer with an Al content of x between0.0005 and 0.05;0 - an undoped Iny(Ga)1-yN layer with an In content of between 0.001and 0.02; -an Mg or Zn doped GaN or AlGaN material layer with a dopantconcentration between 1e161 / cm³ and 8e181 / cm³; -combinations of the above.5 24.Optoelectronic array comprising:2023PF01132 - 41 -- At least two optoelectronic components according to any ofclaims 17 to 21; -wherein the first doped layer of the at least twooptoelectronic components comprise a common material portion,5 said common material portion laterally separating thesemiconductor layer stacks with their respective side surfaces of the regrown semiconductor layers from each other by a distance between centres of two adjacent semiconductor layer stacks depending on a depths of the respective layer stacks and0 the third and / or fourth angle.25.Optoelectronic array according to claim 24, wherein the common material portion is covered by material of the regrown semiconductor layer, a portion of which comprises a surface5 substantially parallel to the active layer of the at least twooptoelectronic components. 26.Optoelectronic array according to claim 24 or 25, wherein - the at least two optoelectronic components are arranged at0 central positions of a virtual hexagonal grid, optionally saidgrid substantially parallel to m-planes of the layer stack; or - the at least two optoelectronic components are arranged at central positions of a virtual gird of rows and columns, optionally said grid substantially parallel to a-planes of the5 layer stack.27.Optoelectronic array according to any of claims 24 to 26, wherein the distance between the centers is at least equal to the sum of its lateral diameter and two times the width of the side surfaces0 of the regrown semiconductor layer measured adjacent to the commonmaterial portion times the tangent of at least one of the third and fourth angle. 28.Optoelectronic array according to any of claims 24 to 27, wherein5 three adjacent optoelectronic components are arranged such thatthe edges of two adjacent side surfaces of adjacent components form an intersection with an angle of appr 120° in between.2023PF01132 - 42 -29.Optoelectronic array according to any of claims 24 to 28, wherein -an edge of a regrown semiconductor layer on a side facet ofeach optoelectronic component intersects with a portion of the regrown layer on the surface portion of the first doped layer5 substantially parallel to the 1210 direction or itsequivalences thereof; and / or -intersections of the regrown layer on the surface portion ofthe first doped layer with the regrown semiconductor layers of two adjacent islands facing each other are substantially0 parallel.30.Optoelectronic array according to any of claims 24 to 27, wherein -edges of the regrown semiconductor layer on the side facets oftwo adjacent optoelectronic components are facing each other;5 and / or- intersections of the regrown layer with the surface portion ofthe first doped layer of two adjacent optoelectronic components form an angle of appr. 120° in between. 0

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