Patent Publication Number: US-2022231195-A1

Title: Optoelectronic semiconductor component comprising connection regions, and method for producing the optoelectronic semiconductor component

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a national stage entry from International Application No. PCT/EP2020/064543, filed on May 26, 2020, published as International Publication No. WO 2020/239749 A1 on Dec. 3, 2020, and claims the priority of German patent application DE 10 2019 114 169.9, filed May 27, 2019, the disclosure contents of all of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     A light emitting diode (LED) is a light emitting device based on semiconductor materials. An LED typically comprises differently doped semiconductor layers and an active zone. When electrons and holes recombine with one another in the regions of the active zone, due, for example, to a corresponding voltage being applied, electromagnetic radiation is generated. 
     In general, concepts are being sought by means of which electrical contacting of the semiconductor layers may be improved. 
     The object of the present invention is to provide an improved optoelectronic semiconductor device and an improved method for manufacturing an optoelectronic semiconductor device. 
     According to the present invention, the object is achieved by the subject matter and the method of the independent claims. Advantageous enhancements are defined in the dependent claims. 
     SUMMARY 
     An optoelectronic semiconductor device comprises a first semiconductor layer stack comprising a first semiconductor layer of a first conductivity type and a second semiconductor layer of a second conductivity type. The optoelectronic semiconductor device further comprises a first contact element and a second contact element, the first semiconductor layer stack and the second semiconductor layer being arranged one above the other and the second semiconductor layer being electrically connected to the second contact element. Part of a first main surface of the first semiconductor layer stack is adjacent to the first contact element, and part of the first main surface of the first semiconductor layer stack is patterned so that a plurality of protruding regions and a plurality of connecting regions are formed. The connecting regions are adjacent to regions in which part of the first main surface of the first semiconductor layer stack is adjacent to the first contact element, and have a lateral extension which is greater than 5 times the mean lateral extension of the protruding regions. 
     In this context, the lateral extension of the connection areas is to be understood as a lateral extension of that part of the connecting regions which is not adjacent to the first contact element. This part of the connecting region may thus be present in a light-emitting region that is not covered by the first contact element. 
     According to further embodiments, the connecting regions may also have a lateral extension which is greater than 10 times the mean lateral extension of the protruding regions. 
     For example, when determining the mean lateral extension of the protruding regions, averaging may be performed over those protruding regions that are not directly adjacent to the first contact element nor to regions of the first main surface in which part of the first main surface of the first semiconductor layer stack is directly adjacent to the first contact element. For example, depressions may be formed within the semiconductor layer stack which separate the protruding regions from the first contact element or from regions of the first main surface adjacent to the first contact element. 
     According to embodiments, the first contact element comprises an electrically conductive material. Part of that part of the first main surface that is patterned is not adjacent to the first contact element and represents a light emitting region. 
     For example, the connecting regions extend from the first contact element into the light emitting regions, respectively. For example, the first contact element encloses the light emitting region. 
     According to embodiments, at least one of the connecting regions extends up to a position within the light emitting region from which a distance to a closest part of the first contact element is greater than a third of a smallest diameter of the light emitting region. 
     According to embodiments, an outermost semiconductor layer of the first semiconductor layer stack is at least partially removed or thinned in the light emitting region. That is to say, the outermost semiconductor layer may be patterned such that it is completely removed or thinned in certain regions, which may be defined photolithographically, for example. According to embodiments, the outermost semiconductor layer may also be completely removed from the light emitting region. 
     For example, a lateral extension of the connecting regions in a direction perpendicular to an extension direction may be greater than a mean lateral extension of the protruding regions. According to embodiments, a structural height of one of the connecting regions may be greater than half a mean lateral extension of the protruding regions. 
     According to embodiments, the first semiconductor layer stack may comprise phosphide semiconductor layers, and the outermost first semiconductor layer contains a phosphide semiconductor material. 
     According to further embodiments, a semiconductor material of the first semiconductor layer stack may comprise a nitride or arsenide semiconductor material. 
     For example, a regions between two protruding regions may have a vertical depth greater than 500 nm and less than 3 μm. 
     According to embodiments, a method for manufacturing an optoelectronic semiconductor device comprises forming a first semiconductor layer stack comprising first semiconductor layers of a first conductivity type and a second semiconductor layer of a second conductivity type. The method further comprises forming a first contact element and a second contact element, the first semiconductor layer stack and the second semiconductor layer being arranged one above the other. The second semiconductor layer is electrically connected to the second contact element. Part of a first main surface of the first semiconductor layer stack is adjacent to the first contact element. Part of the first main surface of the first semiconductor layer stack is patterned, so that a plurality of protruding regions and a plurality of connecting regions are formed. The connecting regions are adjacent to regions in which part of the first main surface of the first semiconductor layer stack is adjacent to the first contact element, and have a lateral extension that is greater than 5 times the mean lateral extension of the protruding regions. 
     For example, patterning may be carried out photolithographically using a photo mask. 
     The method may further comprise removing at least part of an outermost layer of the semiconductor layer stack. For example, the outermost layer of the semiconductor layer stack may be removed or thinned in predetermined regions. The predetermined regions may be defined photolithographically, for example. According to embodiments, the outermost layer may also be completely removed from the light emitting region. 
     According to further embodiments, an optoelectronic semiconductor device comprises a first semiconductor layer stack comprising a first semiconductor layer of a first conductivity type and an epitaxial connecting layer, as well as a second semiconductor layer of a second conductivity type. The optoelectronic semiconductor device further comprises a first contact element and a second contact element. The first semiconductor layer stack and the second semiconductor layer are arranged one above the other. The second semiconductor layer is electrically connected to the second contact element. Part of a first main surface of the first semiconductor layer stack is adjacent to the first contact element, and part of the first main surface of the first semiconductor layer stack is patterned so that a plurality of protruding regions and a plurality of connecting regions are formed. Part of that part of the first main surface that is patterned is not adjacent to the first contact element and represents a light emitting region. The connecting regions extend from the first contact element into the light emitting region, respectively. 
     For example, the connecting regions are adjacent to regions in which part of the first main surface of the first semiconductor layer stack is adjacent to the first contact element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings serve to provide an understanding of exemplary embodiments of the invention. The drawings illustrate exemplary embodiments and, together with the description, serve for explanation thereof. Further exemplary embodiments and many of the intended advantages will become apparent directly from the following detailed description. The elements and structures shown in the drawings are not necessarily shown to scale relative to each other. Like reference numerals refer to like or corresponding elements and structures. 
         FIG. 1A  is a schematic plan view of regions of an optoelectronic semiconductor device according to embodiments. 
         FIG. 1B  is a schematic plan view of regions of an optoelectronic semiconductor device according to further embodiments. 
         FIG. 2A  shows a schematic cross-sectional view of part of an optoelectronic semiconductor device. 
         FIG. 2B  shows a schematic cross-sectional view of part of an optoelectronic semiconductor device according to further embodiments. 
         FIGS. 3A and 3B  are schematic cross-sectional views of part of an optoelectronic semiconductor device according to embodiments. 
         FIG. 4  outlines a method according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part of the disclosure and in which specific exemplary embodiments are shown for purposes of illustration. In this context, directional terminology such as “top”, “bottom”, “front”, “back”, “over”, “on”, “in front”, “behind”, “leading”, “trailing”, etc. refers to the orientation of the figures just described. As the components of the exemplary embodiments may be positioned in different orientations, the directional terminology is used by way of explanation only and is in no way intended to be limiting. 
     The description of the exemplary embodiments is not limiting, since there are also other exemplary embodiments, and structural or logical changes may be made without departing from the scope as defined by the patent claims. In particular, elements of the exemplary embodiments described below may be combined with elements from others of the exemplary embodiments described, unless the context indicates otherwise. 
     The terms “lateral” and “horizontal”, as used in the present description, are intended to describe an orientation or alignment which extends essentially parallel to a first surface of a semiconductor substrate or semiconductor body. This may be the surface of a wafer or a chip (die), for example. 
     The horizontal direction may, for example, be in a plane perpendicular to a direction of growth when layers are grown. 
     The term “vertical”, as used in this description, is intended to describe an orientation which is essentially perpendicular to the first surface of a substrate or semiconductor body. The vertical direction may correspond, for example, to a direction of growth when layers are grown. 
     The terms “wafer” or “semiconductor substrate” used in the following description may include any semiconductor-based structure that has a semiconductor surface. Wafer and structure are to be understood to include doped and undoped semiconductors, epitaxial semiconductor layers, supported by a base, if applicable, and further semiconductor structures. For example, a layer of a first semiconductor material may be grown on a growth substrate made of a second semiconductor material, for example GaAs, GaN or Si, or of an insulating material, for example sapphire. 
     Depending on the intended use, the semiconductor may be based on a direct or an indirect semiconductor material. Examples of semiconductor materials particularly suitable for generating electromagnetic radiation include, without limitation, nitride semiconductor compounds, by means of which, for example, ultraviolet, blue or longer-wave light may be generated, such as GaN, InGaN, AlN, AlGaN, AlGaInN, AlGaInBN, phosphide semiconductor compounds by means of which, for example, green or longer-wave light may be generated, such as GaAsP, AlGaInP, GaP, AlGaP, and other semiconductor materials such as GaAs, AlGaAs, InGaAs, AlInGaAs, SiC, ZnSe, ZnO, Ga 2 O 3 , diamond, hexagonal BN and combinations of the materials mentioned. The stoichiometric ratio of the compound semiconductor materials may vary. Other examples of semiconductor materials may include silicon, silicon germanium, and germanium. In the con text of the present description, the term “semiconductor” also includes organic semiconductor materials. 
     The term “substrate” generally includes insulating, conductive or semiconductor substrates. 
     To the extent used herein, the terms “have”, “include”, “comprise”, and the like are open-ended terms that indicate the presence of said elements or features, but do not exclude the presence of further elements or features. The indefinite articles and the definite articles include both the plural and the singular, unless the context clearly indicates otherwise. 
     In the context of this description, the term “electrically connected” means a low-ohmic electrical connection between the connected elements. The electrically connected elements need not necessarily be directly connected to one another. Further elements may be arranged between electrically connected elements. 
     The term “electrically connected” also encompasses tunnel contacts between the connected elements. 
       FIG. 1A  shows a schematic plan view of part of an optoelectronic semiconductor device  10  according to embodiments. The upper part of  FIG. 1A  shows an enlarged view of part of the surface of the optoelectronic semiconductor device  10  shown in the lower part of  FIG. 1A . 
       FIG. 1A  shows a plan view of a first main surface  112  of the optoelectronic semiconductor device. For example, the electromagnetic radiation  15  generated by the optoelectronic semiconductor device  10  may be emitted via the first main surface  112 . For example, the first main surface  112  simultaneously represents a first main surface of a first semiconductor layer stack, which will be explained in more detail with reference to  FIG. 2A . A first contact element  125  is disposed over part of the first main surface  112 . For example, the first contact element  125  is connected to layers of the first semiconductor layer stack. That part of the first main surface  112  which is not covered with the first contact element  125  may act as a light emitting region  127 , for example. For example, the first contact element  125  may at least partially or completely surround a light emitting region  127 . As shown in particular in the enlarged region of  FIG. 1A , the first main surface  112  of the semiconductor layer stack comprises a plurality of of protruding regions  113 . Furthermore, a plurality of connecting regions  116  is formed. The connecting regions  116  may be linear and may each comprise straight portions. 
     The connecting regions  116  are adjacent to regions in which part of the first main surface of the first semiconductor layer stack is adjacent to the first contact element. The connecting regions  116  are thus electrically connected to the first contact element  125  via these regions. The connecting regions  116  have a lateral extension which is greater than 5 times the mean lateral extension of the protruding regions. The connecting regions  116  may be formed in a straight line, as shown in  FIG. 1B . However, the connecting regions  116  do not necessarily have to be straight. The connecting regions  116  may, for example, also be curved or composed of several straight regions lined up in a row. The term “lateral extension” denotes a length of the connecting regions  116  in a horizontal plane. In the case of curved connecting regions  116 , this may be the arc length, for example. In the case of connecting areas  116  composed of several straight areas lined up in a row, this may be, for example, the sum of the individual distances. 
     According to further embodiments, the connecting regions  116  may have a horizontal dimension (i.e., width) in a direction perpendicular to an extension direction which is greater than the mean horizontal dimension of the protruding regions  113 . 
     As shown in  FIG. 1A , the connecting regions  116  may have several branches. In this manner, efficient lateral current spreading is achieved. For example, the first contact element may comprise an electrically conductive material. The connecting regions  116  are arranged in the light emitting region  127  and extend from the first contact element  125  into the interior of the light emitting region  127 . 
     For example, the material of the first contact element may be a metal or a metal alloy or also comprise an electrically conductive metal oxide. The material of the first contact element  125  may be opaque or transparent. The material of the first contact element  125  may be an Au—Ge alloy, for example. 
     The connecting regions  116  may each extend from the first contact element  125  into the light emitting region  127 . It is provided that the current is impressed into the first semiconductor layer stack via the first contact elements  125  and the connecting regions  116 . 
     For example, the connection regions  116  may extend from the first contact element  125  in the direction of a center point or a central region of the light emitting region  127 . For example, the light emitting region  127  may each be formed to be rectangular and have a smaller diameter and a larger diameter. The connecting region  116  may extend up to a position P within the light emitting region  127 , from which a distance d to a closest part of the first contact element  125  is greater than one third of a smallest diameter of the light emitting region. According to further embodiments, the distance from the position to the closest part of the first contact element  125  may be greater than one half of the smallest diameter of the light emitting region. 
     According to further embodiments, the light emitting region may have any other shape. In this case too, the connection region may extend up to a position within the light emitting region  127  from which a distance to a closest part of the first contact element  125  is greater than one third of a smallest diameter of the light emitting region  127 . In this case too, according to further embodiments, the distance from the position to the closest part of the first contact element  125  may be greater than one half of the smallest diameter of the light emitting region. 
     For example, the light emitting region  127  may also have a square or some other shape having a center point. In this case, for example, the connecting region  116  may extend in the direction of the center point. According to further embodiments, the connecting region  116  may also extend in the direction of a center line which, for example, divides the light emitting region  127  into two regions of the same size and approximately the same shape. The connecting region may branch out several times. According to further embodiments, the connecting region  116  may also extend in the direction of the axis of symmetry of the light emitting region  127 . 
       FIG. 1B  shows a plan view of an optoelectronic semiconductor device in accordance with further embodiments. In principle, the optoelectronic semiconductor device and the connecting regions  116  are configured as illustrated in  FIG. 1A . As shown in  FIG. 1B  and in contrast to  FIG. 1A , the connecting region  116  may have the shape of a straight line and may, for example, extend at a right angle from the first contact element  125  into the light emitting region  127 . As shown in  FIG. 1B , for example, the connecting regions may be arranged at equal distances along a longitudinal direction of the light emitting region  127 . For example, the light emitting region may each have a rectangular shape and the connecting regions are arranged along a longitudinal axis, for example the y-axis, wherein the connecting regions on the left side of the light emitting region  127  are offset from the connecting regions on the right-hand side of the light emitting region  127  and thus form a type of interdigital structure. In this manner, a particularly uniform power supply is made possible. The other components of  FIG. 1B  are similar to those of  FIG. 1A . 
     As further illustrated in  FIG. 1B , the connecting regions  116  have a lateral extension s which is greater than 5 times the mean lateral extension of the protruding regions  113 . A width b, i.e., a lateral extension in a direction perpendicular to a extension direction, may, for example, be greater than a mean lateral extension of the protruding regions. 
       FIG. 2A  shows a schematic cross-sectional view of an optoelectronic semiconductor device in accordance with embodiments. The cross-sectional view shown in  FIG. 2A  is arranged between I and I′, as illustrated in  FIGS. 1A and 1B . 
     The optoelectronic semiconductor device  10  shown in  FIG. 2A  comprises a first semiconductor layer stack  111  comprising a first semiconductor layer of a first conductivity type, for example n-type, and a second semiconductor layer of a second conductivity type, for example p-type. The optoelectronic semiconductor device  10  further comprises a first contact element  125  and a second contact element  129 . The first semiconductor layer stack  111  and the second semiconductor layer  120  are arranged one above the other. The second semiconductor layer  120  is electrically connected to the second contact element  129 . Part of a first main surface  112  of the first semiconductor layer stack  111  is directly adjacent to the first contact element  125  and part of the first main surface of the first semiconductor layer stack is patterned so that a plurality of protruding regions  113  and a plurality of the connecting regions  116  discused above (not shown in  FIG. 2A ) are formed. 
     For example, an active zone  115  may be arranged between the first semiconductor layer stack  111  and the second semiconductor layer  120 . 
     The active zone  115  may, for example, comprise a pn junction, a double heterostructure, a single quantum well structure (SQW, single quantum well) or a multiple quantum well structure (MQW, multi quantum well) for generating radiation. The term “quantum well structure” does not imply any particular meaning here with regard to the dimensionality of the quantization. Therefore it includes, among other things, quantum wells, quantum wires and quantum dots as well as any combination of these layers. 
     In optoelectronic semiconductor devices, the semiconductor layers, each of a different conductivity type, are usually composed of a plurality of individual semiconductor layers of different composition and layer thickness. The semiconductor layers are usually grown epitaxially. The optoelectronic semiconductor device described herein thus contains a first semiconductor layer stack  111  comprising a first semiconductor layer of a first conductivity type, and a second semiconductor layer  120  of a second conductivity type. The second semiconductor layer  120  may also be configured as a layer stack comprising several layers. In the context of the present disclosure, the feature “first semiconductor layer stack comprising a first semiconductor layer of a first conductivity type” also includes the option of the first semiconductor layer stack comprising only one single first semiconductor layer. 
     The uppermost or outermost layer  110  of the first semiconductor layer stack  111  may represent a connecting layer, for example. The connecting layer may be embodied, for example, in such a manner that it has a higher conductivity than other layers within the first semiconductor layer stack  111 . The uppermost or outermost layer  110  may, for example, have a higher doping than other layers within the first semiconductor layer stack  111 . According to further embodiments, the uppermost or outermost layer  110  may have a different composition ratio than other layers within the first semiconductor layer stack  111 . Furthermore, the connecting layer may have a low absorption, for example a lower absorption than a conductive metal oxide layer such as an indium tin oxide layer. For example, it may have a layer thickness of approximately 80 to 120 nm. The first semiconductor layer stack  111  may have a layer thickness of 3 to 3.5 μm, for example. The second semiconductor layer  120  may have a layer thickness of 1.5 to 2 μm. 
     The light emitting surface of an optoelectronic semiconductor device, i.e., the first main surface  112  of the first semiconductor layer stack  111 , is usually patterned or roughened in order to increase the outcoupling efficiency. As a result of this patterning, a plurality of protruding areas  113  is formed. 
     According to embodiments, the first contact element  125  may be adjacent to a patterned part of the first main surface  112  of the first semiconductor layer stack  111 . According to further embodiments, the first main surface  112  of the first semiconductor layer stack  111  may also be unpatterned in a region in which it is adjacent to the first contact element  125  and may form a planar surface. Depressions  114  are usually formed between the adjacent protruding regions  113 . The depressions  114  may extend to different depths t within the first semiconductor layer stack  111 . For example, a depth t of the depressions  114  may be 500 nm to 2 pm or, depending on the material system, up to 3 μm, wherein a depth t of the depressions  114  is measured from the upper edge of the first main surface  112 . The protruding regions  113  may also be arranged adjacent to a depression  114  in a direction perpendicular to the sectional plane shown. That is to say, protruding regions  113  are usually surrounded by depressions  114  in two horizontal directions. Generally, in the context of the present disclosure, protruding regions  113  are generally regions of the first semiconductor layer stack  111  that protrude from one or more adjacent depressions  114 . For example, a height of the protruding regions  113  may be different in each case. Furthermore, a horizontal extension may be different in each case. 
     A material of the second contact element  129  may be identical to or different from the material of the first contact element  125 . According to embodiments illustrated in  FIG. 2A , the second contact element  129  may be arranged on a side of the second semiconductor layer  120  facing away from the active zone. 
       FIG. 2A  further illustrates a hypothetical current flow  117  schematically starting from the first contact element  125 . As shown in  FIG. 2A , current spreading occurs, in particular, first in the vertical direction and then in the horizontal direction. That is to say, with the patterning of the first main surface  112  shown in  FIG. 2A , current spreading occurs over regions below the depression  114 . 
       FIG. 2B  shows a cross-sectional view of the optoelectronic semiconductor device between I and I′ in accordance with further embodiments. The embodiments shown in  FIG. 2B  differ from the embodiments shown in  FIG. 2A  in particular by the changed position of the second contact element  129 . As shown in  FIG. 2B , the second contact element  129  is, in this case, arranged on the side of the second semiconductor layer  120  facing towards the first main surface  112  of the semiconductor layer stack  111 . 
       FIG. 3A  shows a cross-sectional view of the optoelectronic semiconductor device between II and II′, as shown, for example, in  FIG. 1B . 
     As shown in  FIG. 3A , part of the first main surface  112  of the first semiconductor layer stack  111  is patterned in such a manner that connecting regions  116  are formed as explained above. For example, the connecting regions  116  may be unpatterned regions of the semiconductor layer stack  111 . The connecting regions are adjacent to regions in which part of the first main surface  112  of the first semiconductor layer stack is adjacent to the first contact element  125 . 
     As is also shown in  FIG. 3A , in this arrangement, the current flow  117  may also take place via regions of the semiconductor layer stack  111  which are in the vicinity of the first main surface  112 . In this manner, the current impression may be improved. As is shown in the left-hand part of  FIG. 3A , the connecting regions  116  may extend, on the one hand, in the x direction (see  FIG. 1B ). The connecting region or further connecting regions may also extend in the y direction. In this case, a current flow  117  may take place in a direction perpendicular to the plane of representation, as indicated in the right-hand part of  FIG. 3A . 
       FIG. 3A  further illustrates a lateral extension (length) s in the direction of extension of the connecting regions and a lateral extension (width) b perpendicular thereto. 
     As illustrated in  FIG. 3A , the connecting regions may be implemented by unpatterned regions of the first semiconductor layer stack  111 . For example, the connecting regions  116  may be implemented by parts of the top or final semiconductor layer  110 . The uppermost semiconductor layer  110  may thus represent a connecting layer which has been grown epitaxially. The connecting region  116  may be of the first conductivity type. Electromagnetic radiation generated by the optoelectronic semiconductor device may be able to be coupled out via the connecting region  116 . That is to say, the electromagnetic radiation  15  generated is absorbed by the connecting regions only to a small extent or not at all. For example, the connecting region may not contain any layer that has not been epitaxially grown. Furthermore, a surface of the connecting region may be free of any non-epitaxially grown layer. 
     According to further embodiments, as shown, for example, in  FIG. 3B , the connecting regions  116  may also correspond to a patterned part of the first semiconductor layer stack  111 . In  FIG. 3B , the same reference numerals indicate the same components as in  FIG. 3A . In contrast to  FIG. 3A , however, the uppermost or outermost layer  110  of the semiconductor layer stack  111  is additionally patterned, so that, as a result, the connecting region  116  is provided by a partially patterned semiconductor layer stack  111 . For example, a structural height h of the connecting region  116  may be greater than one half of the mean structural height  119  of the protruding regions  113 . The structural height of the connecting region and the averaged structural height are determined in each case in relation to a horizontal reference plane  118 . For example, the horizontal reference plane  118  may be that horizontal plane which corresponds to a termination plane of the deepest depressions  114  or the median of the depressions  114 . Furthermore, the mean structural height of the protruding regions may be an average of the structural heights in relation to this reference plane  118 . 
     As shown in  FIG. 3B , protruding regions  113  are patterned in the uppermost semiconductor layer  110 . According to this embodiment, the current may flow through a large part of the depth of the semiconductor layer stack  111  within the connection region  116 . 
     For example, in the embodiment shown in  FIG. 3B , a semiconductor layer arranged below the uppermost or outermost semiconductor layer  110  may represent the connecting layer. According to embodiments, the uppermost or outermost semiconductor layer  110  may be completely removed in the light emitting region. For example, the uppermost or outermost semiconductor layer  110  may be patterned in such a manner that it has the same or approximately the same lateral extension as the first contact element. Alternatively, the uppermost or outermost semiconductor layer may be thinned in the connection regions  116  and represent the connection layer. 
       FIG. 3B  further illustrates a lateral extension (length) s in the direction of extension of the connecting regions and a lateral extension (width) b perpendicular thereto. 
     For example, the first semiconductor layer stack may comprise phosphide semiconductor layers. Furthermore, the uppermost or outermost semiconductor layer  110  may be a phosphide semiconductor layer. For example, the material system may be an InGaAlP layer system. 
     According to further embodiments, a semiconductor material of the first semiconductor layer stack may comprise a nitride or arsenide semiconductor material. 
     According to an alternative approach, an optoelectronic semiconductor device  10  comprises a first semiconductor layer stack  111  comprising a first semiconductor layer of a first conductivity type and an epitaxial connecting layer, as well as a second semiconductor layer  120  of a second conductivity type. The optoelectronic semiconductor device  10  further comprises a first contact element  125  and a second contact element  129 . The first semiconductor layer stack  111  and the second semiconductor layer  120  are arranged one above the other. The second semiconductor layer  120  is electrically connected to the second contact element  129 . Part of a first main surface  112  of the first semiconductor layer stack  111  is adjacent to the first contact element  125 . Part of the first main surface  112  of the first semiconductor layer stack  111  is patterned so that a plurality of protruding regions  113  and a plurality of connecting regions  116  are formed. Part of that part of the first main surface  112  that is patterned is not adjacent to the first contact element  125  and represents a light emitting region  127 . The connecting regions  116  each extend from the first contact element  125  into the light emitting region  127 . 
     For example, the connecting regions  116  are adjacent to areas in which part of the first main surface  112  of the first semiconductor layer stack  111  is adjacent to the first contact element  125 . 
       FIG. 4  outlines a method according to embodiments. A method for manufacturing an optoelectronic semiconductor device comprises forming (S 100 ) a first semiconductor layer stack comprising first semiconductor layers of a first conductivity type and a second semiconductor layer of a second conductivity type. The method further comprises forming (S 110 ) a first contact element and a second contact element. The first semiconductor layer stack and the second semiconductor layer are arranged one above the other. The second semiconductor layer is electrically connected to the second contact element, wherein part of a first main surface of the first semiconductor layer stack is adjacent to the first contact element. The method further comprises patterning (S 120 ) a part of the first main surface of the first semiconductor layer stack, so that a plurality of protruding regions and a plurality of connecting regions are formed, wherein the connecting regions are adjacent to regions in which part of the first main surface of the first semiconductor layer stack is adjacent to the first contact element, and have a lateral extension that is greater than 5 times the mean lateral extension of the protruding regions. 
     For example, forming (S 110 ) the first contact element may take place before patterning (S 120 ) the part of the first main surface. According to further embodiments, forming (S 110 ) the first contact element may also be carried out after patterning (S 120 ) the part of the first main surface. 
     According to embodiments, patterning of the first main surface of the first semiconductor layer stack may take place using photolithographic processes. A photomask may be constructed or patterned in such a manner that the depressions  114  are formed such that a plurality of protruding regions  113  and a plurality of connecting regions  116  may be patterned. 
     As the first main surface  112  is patterned as described, it is possible, on the one hand, to achieve good out-coupling of generated electromagnetic radiation and good injection of electric current, on the other hand. As a result, the voltage drop across the optoelectronic semiconductor device is reduced. As a result, the efficiency of the optoelectronic semiconductor device may be increased. 
     Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that the specific embodiments shown and described may be replaced by a multiplicity of alternative and/or equivalent configurations without departing from the scope of the invention. The application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is to be limited by the claims and their equivalents only.