Optoelectronic semiconductor component and method for producing at least one optoelectronic semiconductor component

Abstract

An optoelectronic semiconductor component (1) is specified, which comprises: - a semiconductor layer stack (2), - at least one recess (15) that extends from a first main surface (2A) through a first semiconductor region (4) and an active zone (5) and ends in a second semiconductor region (6) of the semiconductor layer stack (2), - a first contact structure (10) for electrically connecting the first semiconductor region (4) arranged at least partly at the first main surface (2A), - a second contact structure (17) for electrically connecting the second semiconductor region (6) arranged partly at the first main surface (2A) and in the at least one recess (15), - a patterned layer (9) at a second main surface (2B) of the semiconductor layer stack (2) having a first thickness (h1) in a first area (9A) laterally overlapping with a contact portion (18) of the second contact structure (17), which is arranged in the at least one recess (15), and having a second thickness (h2) in a second area (9B), which is different from the first area (9A), wherein the first thickness (9A) is smaller than the second thickness (h2). Moreover, a method for producing at least one optoelectronic semiconductor component (1) is specified.

Description

[0001] Description

[0002] OPTOELECTRONIC SEMICONDUCTOR COMPONENT AND METHOD FOR PRODUCING AT LEAST ONE OPTOELECTRONIC SEMICONDUCTOR COMPONENT

[0003] An optoelectronic semiconductor component and a method for producing at least one optoelectronic semiconductor component are speci fied . For example , the optoelectronic semiconductor component is a semiconductor component based on phosphide .

[0004] Radiation-emitting semiconductor components comprising highly doped semiconductor layers and contact vias running through the semiconductor components may suf fer from relatively high absorption of radiation in the highly doped semiconductor layers and at the contact vias .

[0005] It is an obj ect of the present application to speci fy an optoelectronic semiconductor component having an improved optical ef ficiency . It is another obj ect of the present application to speci fy a method for producing at least one optoelectronic semiconductor component having an improved optical ef ficiency .

[0006] These obj ects are achieved inter alia by an optoelectronic semiconductor component and a method for producing at least one optoelectronic semiconductor component having the features of the independent claims .

[0007] Further advantages and configurations of an optoelectronic semiconductor component and of a method for producing at least one optoelectronic semiconductor component are the subj ect matter of the dependent claims . According to at least one embodiment of an optoelectronic semiconductor component , it comprises a semiconductor layer stack including a first semiconductor region, a second semiconductor region and an active zone arranged between the first semiconductor region and the second semiconductor region . The active zone can be provided for generating or emitting electromagnetic radiation having a wavelength or spectral distribution in the visible to infrared spectral range .

[0008] It is possible for the active zone to comprise a sequence of single layers , wherein the single layer sequence may form a quantum well structure like a single quantum well ( SQW) structure or a multiple quantum well (MQW) structure .

[0009] The first semiconductor region may be a region of a first conductivity type , for example of p-conductivity . The second semiconductor region may be a region of a second conductivity type , for example of n-conductivity . However, it is also possible for the first semiconductor region to be a region of n-conductivity and for the second semiconductor region to be a region of p-conductivity . The first and second semiconductor regions can comprise a sequence of single layers in each case , wherein the single layers can be doped or undoped layers . The single layers can be epitaxial layers deposited on a growth substrate . After deposition, the growth substrate can be removed or thinned . Consequently, the optoelectronic semiconductor component may be a thin film component . However, it is also possible for the growth substrate to be preserved as a whole in the finished optoelectronic semiconductor component . According to at least one embodiment , the optoelectronic semiconductor component comprises at least one recess that extends from a first main surface of the semiconductor layer stack through the first semiconductor region and the active zone and ends in the second semiconductor region . The first main surface can be a surface of the semiconductor layer stack, which delimits the semiconductor layer stack on a side facing a rear side of the optoelectronic semiconductor component .

[0010] According to at least one embodiment , the optoelectronic semiconductor component comprises a first contact structure for electrically connecting the first semiconductor region and a second contact structure for electrically connecting the second semiconductor region . The first contact structure can be arranged at least partly at the first main surface . The second contact structure can be arranged partly at the first main surface and in the at least one recess . The second contact structure can comprise a contact portion arranged in the at least one recess . Moreover, the second contact structure or contact portion can comprise a connection layer, which covers the semiconductor layer stack in the at least one recess . By means of the first and second contact structures , it is possible for the optoelectronic semiconductor component to be electrically connected from outside on only one side of the optoelectronic semiconductor component , for example on a side flank .

[0011] According to at least one embodiment , the optoelectronic semiconductor component comprises a patterned layer at a second main surface of the semiconductor layer stack . The second main surface may delimit the semiconductor layer stack on a side opposite to the first main surface . For example , the patterned layer has a first thickness in a first area laterally overlapping with the contact portion of the second contact structure arranged in the at least one recess and has a second thickness in a second area, which is di f ferent from the first area, wherein the first thickness is smaller than the second thickness . For example , the second area laterally surrounds the first area . Moreover, the first area can match an end face of the contact portion in si ze and / or shape and / or lateral position . In the context of the present application, the speci fied si zes may be mean values . Moreover, " lateral" may denote directions parallel to a main extension plane of the optoelectronic semiconductor component . And "vertical" may denote directions perpendicular to the main extension plane . Furthermore , "thickness" may denote an extension along a vertical direction .

[0012] Advantageously, due to the patterned layer being reduced in thickness in the first area where it overlaps with the absorbent contact portion of the second contact structure arranged in the at least one recess , lateral waveguiding and absorption are decreased and less electromagnetic radiation reaches the absorbent contact portion . Consequently, a gain in brightness and an increase in optical ef ficiency can be achieved .

[0013] According to at least one embodiment of an optoelectronic semiconductor component , the optoelectronic semiconductor component comprises :

[0014] - a semiconductor layer stack comprising :

[0015] - a first semiconductor region,

[0016] - a second semiconductor region and

[0017] - an active zone arranged between the first semiconductor region and the second semiconductor region, - at least one recess that extends from a first main surface of the semiconductor layer stack through the first semiconductor region and the active zone and ends in the second semiconductor region,

[0018] - a first contact structure for electrically connecting the first semiconductor region arranged at least partly at the first main surface ,

[0019] - a second contact structure for electrically connecting the second semiconductor region arranged partly at the first main surface and in the at least one recess ,

[0020] - a patterned layer at a second main surface of the semiconductor layer stack having a first thickness in a first area laterally overlapping with a contact portion of the second contact structure , which is arranged in the at least one recess , and having a second thickness in a second area, which is di f ferent from the first area, wherein the first thickness is smaller than the second thickness .

[0021] For example , the at least one recess or contact portion of the second contact structure arranged in the recess can have a three-dimensional shape with a constant cross-section, for example the shape of a cylinder or cuboid . However, it is also possible for the at least one recess or the contact portion arranged in the recess to have a three-dimensional shape with a variable cross-section, for example the shape of a truncated cone or truncated pyramid . The cross-section can become smaller with increasing depth, wherein "depth" may denote an extension along a vertical direction . For example , the shape and si ze of the contact portion are determined by the shape and si ze of the recess . The shape and si ze of the contact portion can at least approximately resemble the shape and si ze of the recess . According to at least one embodiment or configuration, the patterned layer is planar in the first area .

[0022] According to at least one embodiment or configuration, the patterned layer is a semiconductor layer of the second semiconductor region . For example , the patterned layer is a final layer of the second semiconductor region, which is arranged on a side of the second semiconductor region or the semiconductor layer stack facing a front side of the optoelectronic semiconductor component , wherein the front side is opposite to the rear side . The front side may be a radiation exit side of the optoelectronic semiconductor component .

[0023] According to at least one embodiment or configuration, the second semiconductor region is thinner in the first area of the patterned layer than in the second area of the patterned layer .

[0024] According to at least one embodiment or configuration, the patterned layer comprises protrusions spaced apart from each other by depressions . For example , the patterned layer comprises protrusions in the second area . The patterned layer may comprise protrusions only in the second area .

[0025] According to at least one embodiment or configuration, the depressions include a first depression formed in the first area between protrusions of the second area . Moreover, the depressions may include second depressions formed in the second area between protrusions of the second area . For example , the first depression provides a larger space between the protrusions than the second depressions . Hence , the second main surface may be rougher in the second area than in the first area . The patterned layer may serve as an optical structure improving radiation decoupling from the semiconductor layer stack .

[0026] According to at least one embodiment or configuration, the first and second depressions have the same depth . The first and second depressions may be produced in a common patterning step when producing the patterned layer, resulting in the same depth .

[0027] According to at least one embodiment or configuration, the semiconductor layer stack, or at least one of the regions or layers contained in the semiconductor layer stack, comprises or consists of at least one compound semiconductor material based on phosphide . However, it is also possible for the semiconductor layer stack, or at least one of the regions or layers contained in the semiconductor layer stack, to comprise or consist of at least one compound semiconductor material based on nitride or arsenide .

[0028] A compound semiconductor material based on phosphide , nitride or arsenide may denote a material according to the formula AlnGamIni-n-mP, AlnGamIni-n-mN or AlnGamIni-n-mAs where 0 < n < 1 , 0 < m < 1 and n+m < 1 , without necessari ly having a mathematically exact composition according to the above formula . Rather, it may contain one or more dopants and additional components that do not substantially alter the characteristic physical properties of the material . For the sake of simplicity, however, the above formula contains only the essential components of the crystal lattice (Al , Ga, In, P ) , (Al , Ga, In, N) or (Al , Ga, In, As ) , even i f these can be partially replaced by small amounts of other substances . According to at least one embodiment or configuration, the second semiconductor region comprises a contact layer where the at least one recess ends . The contact portion or connection layer of the second contact structure arranged in the at least one recess can be in direct contact with the contact layer where the at least one recess ends . For example , the contact layer is arranged between the active zone and the patterned layer .

[0029] According to at least one embodiment or configuration, the second semiconductor region comprises a current spreading layer on a side of the contact layer facing away from the active layer . For example , the current spreading layer is arranged between the contact layer and the patterned layer .

[0030] According to at least one embodiment or configuration, the contact layer has a higher doping concentration than the current spreading layer . Furthermore , the patterned layer can have a lower doping concentration than the current spreading layer .

[0031] According to at least one embodiment or configuration, the second main surface is free of contact structures , including the first and second contact structures . Thus , absorption can be reduced at the second main surface , where an essential part of the radiation generated in the active zone may be transmitted .

[0032] The subsequently described method is suitable for the production of at least one optoelectronic semiconductor component of the kind mentioned above . The features described in connection with the optoelectronic semiconductor component can therefore also apply to the method, and vice versa . According to at least one embodiment or configuration of a method for producing at least one optoelectronic semiconductor component , the method comprises the following steps , preferably in the following order :

[0033] - providing at least one semiconductor layer stack comprising :

[0034] - a first semiconductor region,

[0035] - a second semiconductor region and

[0036] - an active zone arranged between the first semiconductor region and the second semiconductor region,

[0037] - providing at least one recess that extends from a first main surface of the semiconductor layer stack through the first semiconductor region and the active zone and ends in the second semiconductor region,

[0038] - providing at least one first contact structure for electrically connecting the first semiconductor region arranged at least partly at the first main surface ,

[0039] - providing at least one second contact structure for electrically connecting the second semiconductor region arranged partly at the first main surface and in the at least one recess ,

[0040] - providing a patterned layer at a second main surface of the semiconductor layer stack having a first thickness in a first area laterally overlapping with a contact portion of the second contact structure , which is arranged in the at least one recess , and having a second thickness in a second area, which is di f ferent from the first area, wherein the first thickness is smaller than the second thickness and the patterned layer is formed from an unpatterned layer by removing material in a first area of the unpatterned layer . Especially, the first area of the unpatterned layer matches the first area of the patterned layer in si ze , shape and position .

[0041] For example , the material removal or patterning process can be ef fected by an etching process like a dry and / or wet etching process . The patterning process can be conducted using a mask .

[0042] According to at least one embodiment or configuration, the patterned layer is produced by roughening the second semiconductor region on a side facing away from the active zone .

[0043] According to at least one embodiment or configuration, protrusions spaced apart from each other by depressions are formed in the unpatterned layer when producing the patterned layer . In each case the protrusions can have a prismatic, cuboid, pyramidal , conical or cylindrical three-dimensional shape . For example , dimensions of the protrusions range within a wavelength range of the radiation generated in the active zone during operation .

[0044] According to at least one embodiment or configuration, the depressions are formed including a first depression, which is formed in the first area of the unpatterned layer . Moreover, the depressions are formed including second depressions , which are formed in a second area of the unpatterned layer . For example , the first depression provides a larger space between the protrusions than the second depressions .

[0045] Moreover, the second area can laterally surround the first area . Especially, the second area of the unpatterned layer matches the second area of the patterned layer in si ze , shape and position .

[0046] For example , the space provided by the first depression equals at least the si ze of the end face of the at least one recess or the contact portion .

[0047] The protrusions of the second area can be arranged regularly . The spaces provided by the second depressions can be equal in si ze . However, it is also possible for the protrusions of the second area to be arranged randomly . The spaces provided by the second depressions can vary in this case .

[0048] According to at least one embodiment or configuration, a common mask is used to produce the first and second depressions . This is an ef ficient way to produce the patterned layer .

[0049] The optoelectronic semiconductor component described herein is suitable for visuali zation and sensing applications as well as mobility and illumination applications .

[0050] Further preferred embodiments and developments of the optoelectronic semiconductor component and the method for producing at least one optoelectronic semiconductor component will become apparent from the exemplary embodiments explained below in conj unction with the Figures .

[0051] Figure 1 shows a schematic cross-sectional view of an exemplary embodiment of an optoelectronic semiconductor component , Figures 2A to 2D show schematic cross-sectional views of an optoelectronic semiconductor component during di f ferent stages of an exemplary embodiment of a method for producing at least one optoelectronic semiconductor component .

[0052] Identical , equivalent or equivalently acting elements are indicated with the same reference numerals in the figures . The figures are schematic illustrations and thus not necessarily true to scale . Comparatively small elements and particularly layer thicknesses can rather be illustrated exaggeratedly large for the purpose of better clari fication .

[0053] In connection with Figure 1 , an exemplary embodiment of an optoelectronic semiconductor component is described which can be produced by a method as described in connection with Figures 2A to 2D . The features described in connection with the optoelectronic semiconductor component therefore apply accordingly to the method and vice versa .

[0054] The optoelectronic semiconductor component 1 comprises a carrier 22 and a semiconductor layer stack 2 arranged on the carrier 22 . For example , the carrier 22 is di f ferent from a substrate 3 used during a production process of the semiconductor layer stack 2 ( see Figures 2A and 2C ) . The optoelectronic semiconductor component 1 can be a thin film component , wherein the substrate 3 has been removed or at least thinned . It is possible for the carrier 22 to comprise or consist of semiconductor material like silicon, for example .

[0055] The semiconductor layer stack 2 comprises a first semiconductor region 4 having a first conductivity, for example p-conductivity, a second semiconductor region 6 having a second conductivity, for example n-conductivity, and an active zone 5 arranged between the first semiconductor region 4 and the second semiconductor region 6 . The first semiconductor region 4 can face the carrier 22 , while the second semiconductor region 6 can face away from the carrier 22 .

[0056] The active zone 5 can comprise a quantum well structure like a single quantum well ( SQW) structure or a multiple quantum well (MQW) structure . Moreover, it is possible for the semiconductor layer stack 2 or at least one of the regions 4 , 5 , 6 or layers contained in the semiconductor layer stack 2 to comprise or consist of at least one compound semiconductor material based on phosphide following the formula AlnGamlnx-n-mP where 0 < n < 1 , 0 < m < 1 and n+m < 1 . However, compound semiconductor materials based on nitride or arsenide are also possible .

[0057] For example , the active zone 5 is suitable for generating or emitting electromagnetic radiation having a wavelength or spectral distribution in the visible to infrared spectral range . Accordingly, the optoelectronic semiconductor component 1 can emit electromagnetic radiation having a wavelength or spectral distribution in the visible to infrared spectral range during operation . An essential part of the electromagnetic radiation can be emitted at a front side IB of the optoelectronic semiconductor component 1 .

[0058] The optoelectronic semiconductor component 1 comprises at least one recess 15 that extends from a first main surface 2A of the semiconductor layer stack 2 through the first semiconductor region 4 and the active zone 5 and ends in the second semiconductor region 6 . The first main surface 2A is a surface of the semiconductor layer stack 2 , which delimits the semiconductor layer stack 2 on a side facing a rear side 1A of the optoelectronic semiconductor component 1 . The rear side 1A is opposite to the front side IB . The first main surface 2A can be formed by a surface of the first semiconductor region 4 .

[0059] A first contact structure 10 for electrically connecting the first semiconductor region 4 is arranged at least partly at the first main surface 2A. The first contact structure 10 can comprise a first spreading layer 11 arranged at the first main surface 2A and containing or consisting of TCO ( transparent conductive oxide ) , for example . The first contact structure 10 can comprise a second spreading layer 13 arranged between the first spreading layer 11 and the carrier 22 and containing or consisting of metal , for example . A mirror layer 12 can be arranged between the first and second spreading layers 11 , 13 , which is part of the first contact structure 10 i f it is electrically conductive . For example , the mirror layer 12 contains or consists of metal .

[0060] A second contact structure 17 for electrically connecting the second semiconductor region 6 is arranged partly at the first main surface 2A and in the at least one recess 15 . The second contact structure 17 comprises a contact portion 18 arranged in the at least one recess 15 . The shape and si ze of the contact portion 18 can at least approximately resemble the shape and si ze of the recess 15 . For example , the at least one recess 15 or contact portion 18 can have a three- dimensional shape with a variable cross-section, for example the shape of a truncated cone or truncated pyramid . The cross-section can become smaller with increasing depth . However, it is also possible for the at least one recess 15 or the contact portion 18 to have a three-dimensional shape with a constant cross-section, for example the shape of a cylinder or cuboid .

[0061] The second contact structure 17 can comprise a connection layer 19 , for example a metal layer, which covers the semiconductor layer stack 2 in the at least one recess 15 and is a part of the contact portion 18 . Moreover, the second contact structure 17 can comprise a solder barrier layer 20 and a solder metal layer 21 , in each case covering the main surface 2A of the semiconductor layer stack 2 and extending in the at least one recess 15 so that they form a part of the contact portion 18 . By means of the solder metal layer 21 , the semiconductor layer stack 2 can be mechanically connected to the carrier 22 .

[0062] The optoelectronic semiconductor component 1 comprises a patterned layer 9 at a second main surface 2B of the semiconductor layer stack 2 . The second main surface 2B is arranged opposite to the first main surface 2A and can be a surface of the second semiconductor region 6 facing away from the active zone 5 . The patterned layer 9 can be a final layer of the second semiconductor region 6 , wherein the second main surface 2B is a surface of the patterned layer 9 , for example .

[0063] The patterned layer 9 has a first thickness hl in a first area 9A laterally overlapping with the contact portion 18 and has a second thickness h2 in a second area 9B, which is di f ferent from the first area 9A and may laterally surround the first area 9A. Especially, the first thickness hl is smaller than the second thickness h2 , wherein the first thickness hl can tend to zero or be zero and the second thickness h2 can have a mean value ranging from 100 nm to 200 nm, for example , wherein tolerances of ± 10% are possible . Due to the patterned layer 9 being a part of the second semiconductor region 6 , the second semiconductor region 6 is thinner in the first area 9A of the patterned layer 9 than in the second area 9B of the patterned layer .

[0064] The first area 9A can match an end face 18A of the contact portion 18 arranged at an end face 15A of the recess 15 in si ze , shape and lateral position .

[0065] "Lateral" denotes directions L parallel to a main extension plane of the optoelectronic semiconductor component 1 , for example . And "vertical" denotes directions perpendicular to the main extension plane , for example . Furthermore , "thickness" or "depth" denotes an extension along a vertical direction V, for example .

[0066] The second semiconductor region 6 can comprise a contact layer 7 between the active zone 5 and the patterned layer 9 , where the at least one recess 15 ends . The contact portion 18 or connection layer 19 can be in direct contact with the contact layer 7 at the end face 18A of the contact portion 18 or the end face 15A of the recess 15 . The contact layer 7 may have a thickness , which ranges from 40 nm to 60 nm, for example , wherein tolerances of ± 10% are possible .

[0067] Moreover, the second semiconductor region 6 can comprise a current spreading layer 8 on a side of the contact layer 7 facing away from the active layer 5 , for example between the contact layer 7 and the patterned layer 9 . The contact layer 7 can have a higher doping concentration than the current spreading layer 8 , while the patterned layer 9 may have a lower doping concentration than the current spreading layer 8 . Moreover, the current spreading layer 8 may have a thickness which is greater than the thickness of the contact layer 7 and ranges from 300 nm to 500 nm, for example , wherein tolerances of ± 10% are possible .

[0068] Advantageously, due to the patterned layer 9 being reduced in thickness in the first area 9A, where it overlaps with the absorbent contact portion 18 , lateral waveguiding and absorption are decreased and less electromagnetic radiation reaches the absorbent contact portion 18 . Consequently, a gain in brightness and optical ef ficiency can be achieved . For example , in the first area 9A, the second semiconductor region 6 has a thickness h which ranges from 100 nm to 600 nm for example , wherein tolerances of ± 10% are possible . Especially, in the first area 9A, the second semiconductor region 6 has a thickness which corresponds to a sum of the layer thicknesses of the contact layer 7 , the current spreading layer 8 and the patterned layer 9 .

[0069] The patterned layer 9 can be planar in the first area 9A and can comprise protrusions 90 for example only in the second area 9B, wherein the protrusions 90 are spaced apart from each other by depressions , including a first depression 91 and second depressions 92 . For example , the first depression 91 is formed in the first area 9A between the protrusions 90 of the second area 9B . And the second depressions 92 can be formed in the second area 9B between the protrusions 90 of the second area 9B . Especially, the first depression 91 provides a larger first space al between the protrusions 90 than the second depressions 92 , which provide a second space a2 in each case . Hence , the second main surface 2B may be rougher in the second area 9B than in the first area 9A. For example , the first space al provided by the first depression

[0070] 91 equals at least the si ze of the end face 18A of the contact portion 18 or the end face 15A of the recess 15 . Suitable dimensions of the first space al are in the onedigit to two-digit micrometer range , for example between 2pm and 50 pm, wherein tolerances of ± 10% are possible . Suitable dimensions of the second spaces a2 are in each case in the submicrometer to one-digit micrometer range , for example at most 2pm, wherein tolerances of ± 10% are possible .

[0071] The protrusions 90 of the second area 9B can be arranged regularly . The spaces a2 provided by the second depressions

[0072] 92 can be equal in si ze . However, it is also possible for the protrusions 90 of the second area 9B to be arranged randomly . The spaces a2 provided by the second depressions 92 can vary in this case . "Space" may denote an extension along the lateral direction L . The first and second depressions 91 , 92 have the same depth d, for example .

[0073] The protrusions 90 can have in each case a prismatic, cuboid, pyramidal , conical or cylindrical three-dimensional shape .

[0074] For example , dimensions of the protrusions 90 range within a wavelength range of the generated radiation .

[0075] The patterned layer 9 may serve as an optical structure improving radiation decoupling from the semiconductor layer stack 2 and thus improving the optical ef ficiency .

[0076] Moreover, it is possible for the second main surface 2B to be free of contact structures , including the first and second contact structures 10 , 17 , so that absorption can be reduced at the front side IB and the optical ef ficiency can be improved . The first and second contact structures 10 , 17 allow the optoelectronic semiconductor component 1 to be electrically connected from outside on only one side of the optoelectronic semiconductor component 1 , for example on a side flank . For example , a first contact pad 23 of the first contact structure 10 which serves as a first electrode of the optoelectronic semiconductor component 1 , and a second contact pad (not shown) of the second contact structure 17 which serves as a second electrode of the optoelectronic semiconductor component 1 , may be arranged laterally of the semiconductor layer stack 2 on a proj ecting region of the carrier 22 and may be provided for the connection with contact means , for example bonding wires .

[0077] In the proj ecting region, for example , the first contact pad 23 is arranged on a reflective element 14 and extends through an opening 14A of the reflective element 14 to the second spreading layer 13 of the first contact structure 10 . The reflective element 14 , which is a dielectric mirror for example , can cover the first main surface 2A. The second spreading layer 13 , as well as the mirror layer 12 , can extend through an opening 14B of the reflective element 14 to the first spreading layer 11 .

[0078] In order to electrically isolate the first and second contact structures 10 , 17 , for example , the optoelectronic semiconductor component 1 comprises an insulation layer 16 arranged between the semiconductor layer stack 2 and the connection layer 19 and covering side faces 15B of the recess 15 and also comprises an insulation layer 24 arranged at the first main surface 2A between the second spreading layer 13 and the solder barrier layer 20 . In connection with Figures 2A to 2D, an exemplary embodiment of a method for producing at least one optoelectronic semiconductor component 1 of the kind as explained in connection with Figure 1 is described .

[0079] As shown in Figure 2A, the method comprises providing a semiconductor layer stack 2 on a substrate 3 , wherein the semiconductor layer stack 2 includes a second semiconductor region 6 of a second conductivity, for example of n- conductivity, adj acent to the substrate 3 , an active zone 5 adj acent to the second semiconductor region 6 and a first semiconductor region 4 of a first conductivity, for example of p-conductivity, adj acent to the active zone 5 . However, it is also possible for the first and second conductivity to be switched . The regions 4 , 5 , 6 or single layers of the semiconductor layer stack 2 can be epitaxially deposited on the substrate 3 . The substrate 3 can be a semiconductor substrate , for example based on an arsenide compound semiconductor material like GaAs .

[0080] The semiconductor layer stack 2 can be provided with a first contact structure 10 on a first main surface 2A facing away from the substrate 3 , wherein the first contact structure 10 partly covers the first main surface 2A. The first contact structure 10 can comprise a first spreading layer 11 contacting the first semiconductor region 4 , a mirror layer 12 contacting the first spreading layer 11 and a second spreading layer 13 contacting the mirror layer 12 , wherein the mirror layer 12 and the second spreading layer 13 are sandwiched between a reflective element 14 and an insulation layer 24 and the reflective element 14 is adj acent to the first spreading layer 11 . The dashed areas in the Figures symboli ze an enlarged layer composite that can be provided to produce more than one optoelectronic semiconductor component 1 .

[0081] As shown in Figure 2B, the method further comprises providing a recess 15 that extends from the first main surface 2A of the semiconductor layer stack 2 through the first semiconductor region 4 and the active zone 5 and ends in the second semiconductor region 6 . The at least one recess 15 can be produced in a two-step etching process including for example dry and wet etching processes , wherein a first etching step can stop between the active zone 5 and a contact layer 7 of the second semiconductor region 6 and a second etching step can stop at the contact layer 7 , for example resulting in a broadened region at the end face 15A of the at least one recess 15 .

[0082] As shown in Figures 2B and 2C, the method further comprises providing a second contact structure 17 , which is arranged partly at the first main surface 2A and in the recess 15 and includes a connection layer 19 arranged in the recess 15 on the semiconductor layer stack 2 . The connection layer 19 covers the end face 15A of the recess 15 , where it is in direct contact with the contact layer 7 . Furthermore , the connection layer 19 covers side surfaces 15B of the recess 15 , wherein an insulation layer 16 is arranged between the semiconductor layer stack 2 and the connection layer 19 and extends as far as the insulation layer 24 .

[0083] Furthermore , the second contact structure 17 can be provided with a solder barrier layer 20 and a solder metal layer 21 , which in each case are arranged in the recess 15 and extend as far as the first main surface 2A. The method further comprises providing a carrier 22 on a side of the stack of layers 2 , 10 , 17 facing away from the substrate 3 ( see Figure 2C ) and removing the substrate 3 ( see Figure 2D) .

[0084] As shown in Figure 2D, the method further comprises a patterning process ( see arrows ) , especially a roughening process , which is conducted on a side of the second semiconductor region 6 where the substrate 3 has been removed . The patterning process includes forming a patterned layer 9 ( see Figure 1 ) from an unpatterned layer 25 of the semiconductor layer stack 2 by removing material in a first area 25A of the unpatterned layer 25 in order to produce the first area 9A of the patterned layer 9 and in a second area 25B of the unpatterned layer 25 in order to produce the second area 9B of the patterned layer 9 . Especially, the patterning process comprises producing protrusions 90 spaced apart from each other by depressions 91 , 92 ( see Figure 1 ) , wherein a first depression 91 is formed in the first area 25A of the unpatterned layer 25 and second depressions 25B are formed in the second area 25B of the unpatterned layer 25 . The patterning process can be conducted by using a mask 26 , for example a common mask for producing all depressions 91 , 92 , which is an ef ficient way to produce the patterned layer 9 . For example , the material removal or patterning process can be ef fected by an etching process like a dry and / or wet etching process .

[0085] The method can comprise further steps like providing a contact pad 23 ( see Figure 1 ) .

[0086] The invention is not limited to these embodiments by the description based on the embodiments . Rather, the invention includes any new feature and any combination of features, which includes in particular any combination of features in the patent claims, even if this feature or this combination itself is not explicitly explained in the patent claims or embodiments.

[0087] This patent application claims the priority of German patent application 102024115447.0, the disclosure content of which is hereby incorporated by reference.

[0088] References

[0089] 1 optoelectronic semiconductor component

[0090] 1A rear side

[0091] IB front side

[0092] 2 semiconductor layer stack

[0093] 2A first main surface

[0094] 2B second main surface

[0095] 3 substrate

[0096] 4 first semiconductor region

[0097] 5 active zone

[0098] 6 second semiconductor region

[0099] 7 contact layer

[0100] 8 current spreading layer

[0101] 9 patterned layer

[0102] 9A first area

[0103] 9B second area

[0104] 10 first contact structure

[0105] 11 first spreading layer

[0106] 12 mirror layer

[0107] 13 second spreading layer

[0108] 14 reflective element

[0109] 14A, 14B opening

[0110] 15 recess

[0111] 15A end face

[0112] 15B side surface

[0113] 16 insulation layer

[0114] 17 second contact structure

[0115] 18 contact portion

[0116] 18A end face

[0117] 19 connection layer

[0118] 20 solder barrier layer

[0119] 21 solder metal layer 22 carrier

[0120] 23 contact pad

[0121] 24 insulation layer

[0122] 25 unpatterned layer

[0123] 25A first area

[0124] 25B second area

[0125] 26 mask

[0126] 90 protrusion

[0127] 91 first depression

[0128] 92 second depression al first space a2 second space d depth h thickness hl first thickness h2 second thickness

[0129] V vertical direction

[0130] L lateral direction

Claims

Claims1. An optoelectronic semiconductor component (1) comprising:- a semiconductor layer stack (2) comprising:- a first semiconductor region (4) ,- a second semiconductor region (6) and- an active zone (5) arranged between the first semiconductor region (4) and the second semiconductor region ( 6 ) ,- at least one recess (15) that extends from a first main surface (2A) of the semiconductor layer stack (2) through the first semiconductor region (4) and the active zone (5) and ends in the second semiconductor region (6) ,- a first contact structure (10) for electrically connecting the first semiconductor region (4) arranged at least partly at the first main surface (2A) ,- a second contact structure (17) for electrically connecting the second semiconductor region (6) arranged partly at the first main surface (2A) and in the at least one recess ( 15) ,- a patterned layer (9) at a second main surface (2B) of the semiconductor layer stack (2) having a first thickness (hl) in a first area (9A) laterally overlapping with a contact portion (18) of the second contact structure (17) , which is arranged in the at least one recess (15) , and having a second thickness (h2) in a second area (9B) , which is different from the first area (9A) , wherein the first thickness (hl) is smaller than the second thickness (h2) and the patterned layer (9) comprises protrusions (90) spaced apart from each other by depressions (91, 92) , wherein a first depression (91) is formed in the first area (9A) between protrusions (90) of the second area (9B) and seconddepressions (92) are formed in the second area (9B) between protrusions (90) of the second area (9B) and the first depression (91) provides a larger space (al) between the protrusions (90) than the second depressions (92) .

2. The optoelectronic semiconductor component (1) according to the previous claim, wherein the patterned layer (9) is a semiconductor layer of the second semiconductor region (6) .

3. The optoelectronic semiconductor component (1) according to any of the previous claims, wherein the patterned layer (9) is a final layer of the second semiconductor region (6) and the second main surface (2B) is a surface of the patterned layer (9) .

4. The optoelectronic semiconductor component (1) according to any of the previous claims, wherein the first and second depressions (91, 92) have the same depth (d) .

5. The optoelectronic semiconductor component (1) according to any of the previous claims, wherein the semiconductor layer stack (2) or at least one of the regions (4, 5, 6) or layers contained in the semiconductor layer stack (2) comprises or consists of at least one compound semiconductor material based on phosphide.

6. The optoelectronic semiconductor component (1) according to any of the previous claims, wherein the second main surface (2A) is free of contact structures including the first and second contact structures (10, 17) .

7. The optoelectronic semiconductor component (1) according to any of the previous claims, wherein the secondsemiconductor region (6) comprises a contact layer (7) where the at least one recess ends (15) .

8. The optoelectronic semiconductor component (1) according to the previous claim, wherein the second semiconductor region (6) comprises a current spreading layer (8) on a side of the contact layer (7) facing away from the active zone (5) .

9. The optoelectronic semiconductor component (1) according to any of the two previous claims, wherein the contact layer (7) has a higher doping concentration than the current spreading layer (8) .

10. The optoelectronic semiconductor component (1) according to the previous claim, wherein the patterned layer (9) has a lower doping concentration than the current spreading layer (8) .

11. The optoelectronic semiconductor component (1) according to any of the previous claims, wherein the second contact structure (17) comprises a connection layer (19) and the connection layer (19) covers the semiconductor layer stack (2) in the at least one recess (15) .

12. A method for producing at least one optoelectronic semiconductor component (1) , wherein the method comprises: - providing at least one semiconductor layer stack (2) comprising :- a first semiconductor region (4) ,- a second semiconductor region (6) and- an active zone (5) arranged between the first semiconductor region (4) and the second semiconductor region ( 6 ) ,- providing at least one recess (15) that extends from a first main surface (2A) of the semiconductor layer stack (2) through the first semiconductor region (4) and the active zone (5) and ends in the second semiconductor region ( 6 ) ,- providing at least one first contact structure (10) for electrically connecting the first semiconductor region (4) arranged at least partly at the first main surface (2A) ,- providing at least one second contact structure (17) for electrically connecting the second semiconductor region (6) arranged partly at the first main surface (2A) and in the at least one recess (15) ,- providing a patterned layer (9) at a second main surface (2B) of the semiconductor layer stack (2) having a first thickness (hl) in a first area (9A) laterally overlapping with a contact portion (18) of the second contact structure (17) , which is arranged in the at least one recess (15) , and having a second thickness (h2) in a second area (9B) , which is different from the first area( 9A) , wherein the first thickness (hl) is smaller than the second thickness (h2) and the patterned layer (9) is formed from an unpatterned layer (25) by removing material in a first area (25A) of the unpatterned layer (25) , wherein protrusions (90) spaced apart from each other by depressions (91, 92) are formed in the unpatterned layer (25) when producing the patterned layer (9) and a first depression (91) is formed in the first area (25A) of the unpatterned layer (25) and second depressions (92) are formed in a second area (25B) of the unpatterned layer (25) .

13. The method according to the previous claim, wherein the patterned layer (9) is produced by roughening the second semiconductor region (6) on a side facing away from the active zone (5) .

14. The method according to any of the two previous claims, wherein a common mask (26) is used to produce the first and second depressions (91, 92) .

15. The method according to any of claims 12 to 14, wherein at least one optoelectronic semiconductor component (1) according to claims 1 to 11 is produced.

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