Power semiconductor device

Abstract

In one embodiment, the power semiconductor device (1) comprises - a first electrode (21) and a second electrode (22), and - a semiconductor layer sequence (3), wherein - seen along a vertical direction (V), the semiconductor layer sequence (3) comprises a first region (31) of a first conductivity type, a second region (32) adjacent to the second electrode (22) of a second conductivity type, and a reverse layer (44) of the second conductivity type between the first electrode (21) and the first region (31), - the first region (31) comprises extensions (5, 51, 52, 53) running through the reverse layer (44), - seen in top view of the first electrode (21), the reverse layer (44) comprises a central area (41), an intermediate area (42) and an edge area (43) in which the extensions (5, 51, 52, 53) have different area proportions and / or sizes, respectively.

Description

[0001]P2024,0573 WO N / P230208WO01 June 3,2025 -1 - Description Powersemiconductordevice A powersemiconductordevice isprovided.Documents WO 2023 / 099298 A1 and WO 2020 / 201361 A1 r efer tosemiconductordevices.Document WO 2024 / 200266 A1 refers to a power semico nductordevice.Documents US 2017 / 0263785 A1, US 2024 / 0038878 A1 an d US2010 / 0276727 A1 refer to power semiconductor device s.A problem to be solved is to provide a power semico nductordevice thathasimproved electricalbehavior.This object is achieved, inter alia, by a power sem iconductordevice as defined in the independent claim. Exempla ry furtherdevelopments constitute the subject-matter of the d ependentclaims.For example, the power semiconductor device compris es areverse layer which may be p+-doped next to a firstelectrode, and a plurality of extensions run throug h thereverse layer. For example, the extensions are n+-d oped andmay reach the firstelectrode.The extensionshave differentarea proportions and / or sizes in a central area, anintermediate area and an edge area, respectively, o f thereverse layer, seen in top view. It is possible tha t thepower semiconductor device is a fast recovery diode , FRD forshort. By having the at least three areas, recovery softness P2024,0573 WO N / P230208WO01 June 3,2025 -2 -at low currents can be maintained and a maximum for ward surgecurrent,IFSM,capabilitycan be improved.According to at least one embodiment, the power sem iconductordevice comprises a first electrode and a second ele ctrode.The second electrode and the first electrode can be locatedon opposing sides of a semiconductor layer sequence of thepower semiconductor device. The first and / or the se condelectrode can be of single-layer fashion or of mult i-layerfashion. According to atleastone embodiment,seen along a verticaldirection, the semiconductor layer sequence compris es a firstregion of a first conductivity type. For example, t he firstregion touchesthe firstelectrode.Itispossible thatthefirst region is composed of a plurality of layers h avingdifferentmaximum doping concentrations. Forexample,the verticaldirection isa directionperpendicular to the first and / or second electrode. Thevertical direction may be in parallel with a direct ion ofmain electron flow when the power semiconductor dev ice is ina conductive state. The term ‘vertical direction’ m ay notimply ‘from below to above’ or ‘from above to below ’ so thatit may refer to an orientation but not to a vector.According to at least one embodiment, seen along th e verticaldirection, the semiconductor layer sequence compris es asecond region of a second conductivity type. The se condconductivity type is different from the first condu ctivitytype. The conductivity types are n-conductive and p -conductive. The second region is adjacent to the se cond P2024,0573 WO N / P230208WO01 June 3,2025 -3 -electrode. That is, the second region may touch the secondelectrode, for example, all along the second electr ode.According to at least one embodiment, the semicondu ctor layersequence comprises a reverse layer of the second co nductivitytype. The reverse layer is located partially or com pletelybetween the first electrode and the first region. F orexample, the reverse layer is distant from the seco nd region.According to at least one embodiment, the first reg ioncomprises a plurality of extensions. The extensions runthrough the reverse layer along the vertical direct iontowards the first electrode. Especially, the extens ionscompletely penetrate the reverse layer and can thus touch thefirstelectrode.According to at least one embodiment, seen in top v iew of thefirst electrode, the reverse layer comprises a cent ral area,an intermediate area and an edge area.In addition to theseareas it is in principle possible that there are fu rtherareasso thatthe overallnumberofareasdoesnot need to belimited to three. For example, there are at most te n or atmostsixoratmostfourofsuch areas.According to at least one embodiment, the extension s havedifferent area proportions and / or sizes in the cent ral,intermediate and edge areas, respectively. In other words,the different areas can be defined as containing so lely orpredominantly extensions of a specific area proport ion and / orsize. ‘Predominantly’ means, for example, that at l east 90%or at least 95% of the extensions have the specific areaproportion and / or size assigned to the respective a rea. Forexample, the area proportions and / or sizes of the e xtensions P2024,0573 WO N / P230208WO01 June 3,2025 -4 -are unique in the central, intermediate and edge ar eas,respectively. In other words, it is possible that i n none ofthe central, intermediate and edge areas, respectiv ely, thereis the same area proportion and / or size of the exte nsions.Thus,the area proportionsand / orsizespresentin thecentral, intermediate and edge areas can be differe ntpairwisely.For example, in the central area the extensions hav e a firstsize,in the intermediate area the extensionshave a secondsize, and in the edge area the extensions have a th ird size,and the first size is different from the second and the thirdsize and the second size is different from the thir d size.Hence, there can be three distinct sizes. All the e xtensionsin the respective area can be of the same size, for example,all the extensions in the central area are of the f irst size,allthe extensionsin the intermediate area are of the secondsize, and all the extensions in the edge area are o f thethird size.In at least one embodiment, the power semiconductor devicecomprises -a firstelectrode and a second electrode,and -a semiconductorlayersequence, wherein- seen along a vertical direction, the semiconducto r layersequence comprises a first region of a first conduc tivitytype, a second region adjacent to the second electr ode of asecond conductivitytype differentfrom the firstconductivity type, and a reverse layer of the secon dconductivity type between the first electrode and t he firstregion,- the first region comprises a plurality of extensi ons P2024,0573 WO N / P230208WO01 June 3,2025 -5 -running through the reverse layer along the vertica ldirection towardsthe firstelectrode,- seen in top view of the first electrode, the reve rse layercomprisesa centralarea,an intermediate area and an edgearea in which the extensions have different area pr oportionsand / orsizes,respectively.With this design, an improved performance of fast r ecoverydiodes and reverse conducting integrated gate-commu tatedthyristors,RC-IGCTs,can be achieved.Fast recovery diode having cathode segments, that i s, astructured cathode at which an n +-region is interrupted byshallow p +-regions, offer reverse recovery softness. However,there is a trade-off between reverse recovery softn ess andsurge currentaswellaslossesso thatthere isatechnological trade-off. Wider cathode segments off er verysoft reverse recovery but surfer in surge current c apabilityand losses. Whereas medium-sized cathode segments o fferbetter surge current capability and improved techno logytrade-off, such segments lead to a snappier reverse recoveryatlowercurrents.In the power semiconductor device described herein, the FRDis designed with multiple cathode segment dimension s, forexample, with a combination of wider, medium and na rrowsegments, to improve reverse recovery softness, sur ge currentand technology trade-off compared to either wider c athodesegmentsormedium segments.Wider cathode segments, that is, for example, wider n +-regions and p +-regions, offer very soft reverse recovery butpoor surge current capability. Medium cathode segme nts, that P2024,0573 WO N / P230208WO01 June 3,2025 -6 -is, for example, with medium-sized n +-regions and p +-regions,offerbettersurge currentcapabilityand improved technology trade-offbutare snappieratverylow currents. In the powersemiconductordevice described herein the FRD isdesigned with multiple cathode segment dimensions t o improvereverse recovery softness, surge current and techno logytrade-off compared to either wider cathode segments ormedium-sized segments. Wider segments in, for examp le, 10% to20% of an active area in the center of the device h elp toimprove reverse recovery softness whereas medium-si zedsegments in 70% to 80% of the active area, for exam ple, helpto improve surge currentcapabilityand technology trade-off, and narrow segmentsin,forexample,10% to 20% of the activearea near the termination region and in the termina tionregion help to improve frequency turn-off robustnes s. Inaddition, using said design can enable to use thinn er wafersto produce the power semiconductor device so that c osts canbe reduced while the use of three instead of one or twostructural sizes does not significantly increase pr oductioncosts as all the segments can be structured using a same maskand / orimplantation step.According to at least one embodiment, the first ele ctrode isa cathode, the second electrode is an anode, the fi rstconductivitytype isn-conductive,and the secondconductivity type is p-conductive. However, in prin ciple theconductivity types and cathode / anode functionalitie s couldalso be the opposite.According to at least one embodiment, the reverse l ayer isdirectlyatthe firstelectrode and the extensions touch the firstelectrode and are in directcontactwith the reverse P2024,0573 WO N / P230208WO01 June 3,2025 -7 - layer.Forexample,the reverse layerisin direct contact onlywith the firstregion and the firstelectrode and,ataperipheral edge of the semiconductor layer sequence ,optionallywith a passivation layerofthe power semiconductordevice.According to at least one embodiment, the first reg ioncomprisesa driftregion.The driftregion maythe layerof the firstregion being mostdistantfrom the first electrode.For example, the drift region is the thickest layer of thefirstregion.Itispossible thatthe driftregion isindirect contact with the second region. In addition, the firstregion may comprise a buffer layer between the drif t regionand the first electrode and a contact layer. The co ntactlayer may constitute the extensions. Further option ally, theextensionsmayextend into the bufferlayerand / or the drift region.According to at least one embodiment, the central a rea has atleast two axes of mirror symmetry, seen in top view . Forexample,the centralarea isofcircularshape.According to at least one embodiment, the intermedi ate areasurrounds the central area, for example, directly s urroundsthe central area. The intermediate area may directl y adjointhe central area, for example, all around. It is po ssiblethat the intermediate area is of ring-shape, especi allycompletelyaround the centralarea.According to at least one embodiment, the edge area surroundsthe intermediate area, for example, directly surrou nds theintermediate area. The edge area may directly adjoi n theintermediate area, for example, all around. It is p ossible P2024,0573 WO N / P230208WO01 June 3,2025 -8 -that the edge area is of ring-shape, especially com pletelyaround the intermediate area.According to at least one embodiment, seen in top v iew of thefirst electrode, the extensions are of island-shape . In otherwords, there can be a plurality of distinct extensi ons. Theextensions may not touch each other. Thus, directly at thefirstelectrode the extensionsmaybe distantfrom eachother. It is possible that all the extensions or at least theextensionsnotdirectlyatthe peripheraledge are completelysurrounded by the reverse layer, especially directl ysurrounded by the reverse layer. This may be true d irectly atthe first electrode and / or all along the extensions on theirwaythrough the reverse layer.According to at least one embodiment, seen in top v iew of thefirst electrode, the extensions have at least one o f acircular, ring, triangular, square, rectangular, he xagonal orn-polygonal shape, in case of the n-polygonal shape withn ≥ 8. It is possible that all the extensions have the samebasic shape, seen in top view, like being hexagonal .Otherwise, differently shaped extensions can be com bined witheach other, for example, circular extensions may be combinedwith square and / orhexagonalextensions.According to at least one embodiment, the reverse l ayer ispresent all along the first electrode. Thus, the re verselayer can be a continuous, uninterrupted layer. Thi s means,for example, that a doping, like a p +-doping, is present alloverthe firstelectrode.According to at least one embodiment, the extension s overlapin volume with the reverse layer. For example, a ma ximum P2024,0573 WO N / P230208WO01 June 3,2025 -9 -doping concentration of the extensions exceeds a ma ximumdoping concentration of the reverse layer by at lea st afactor of ten or by at least a factor of 50. In oth er words,the conductivitytype ofthe reverse layermaybe‘overwritten’ by the significantly higher implement ed dopingof the extensions of the other conductivity type. H ence, p-doping and strongern-doping maybe presentin the volume of the extensionsrunning through the reverse layer.Otherwise, it is possible that the reverse layer an d theextension do not or do not significantly overlap in volume sothat in the volume of the extensions only one dopin g type,like n-doping,maybe present.According to at least one embodiment, the reverse l ayer isthinner than the extensions, seen along the vertica ldirection. Otherwise, the reverse layer and the ext ensionsmay have a same thickness or the extensions may eve n bethickerthan the reverse layer.According to at least one embodiment, first ones of theextensions of the central area are larger than seco nd ones ofthe extensions of the intermediate area. Alternativ ely oradditionally, the second ones of the extensions are largerthan third ones of the extensions of the edge area. Forbrevity, the first ones of the extensions are refer red to asfirst extensions, and analogously the terms ‘secondextensions’and ‘third extensions’are used.According to at least one embodiment, first ones of theextensions of the central area are larger than thir d ones ofthe extensions of the edge area. Further, the inter mediatearea comprises a second one of the extensions and s aid one or P2024,0573 WO N / P230208WO01 June 3,2025 -10 -plurality of second extensions has an area proporti on of atleast 70% or of at least 85% of the intermediate ar ea. Hence,it is possible that there is just one second extens ion andsaid second extension may completely or virtually c ompletelyconstitute the intermediate area.According to at least one embodiment, the first one s of theextensions extend into the intermediate area but no t into theedge area. In other words, in the intermediate area there aresome of the first extensions. Thus, in the intermed iate areathe first and second extensions may coexist. For ex ample, atleast90% oratleast95% ofthe extensionsin theintermediate area are second extensions so that the secondextensions are the by far predominant species. In t his case,the intermediate area may be of ring-shape, for exa mple.According to at least one embodiment, the intermedi ate areadirectly adjoins the central area and the edge area directlyadjoinsthe intermediate area.In thiscase,there can beexactly the central, intermediate and edge areas wi thout anyfurtherareas.According to at least one embodiment, the edge area is anoutermostregion ofthe reverse layer,seen in top view ofthe first electrode. For example, the edge area for ms aperipheral edge of the semiconductor layer sequence , possiblytogether with other layers and / or regions of the fi rstregion.According to at least one embodiment, the central a rea, theintermediate area and the edge area are continuous areas.That is, the respective areas are not constituted b y sub-areasbutbyjustone space. P2024,0573 WO N / P230208WO01 June 3,2025 -11 -For example, the central area is a simply connected spacewhile the intermediate area and the edge area could beconnected spaces of genius 1. Possible further area s may besimply connected spaces or connected spaces of geni us 1 aswell.Hence,the centralarea can be a hole-free,uninterrupted area, seen in top view of the first e lectrode,while the intermediate area and the edge area can h aveexactlyone hole.According to at least one embodiment, the central a reaamounts for at least 3% or for at least 5% or for a t least 8%orforatleast10% ofan active area content.The activearea content is, for example, a size of the first e lectrodeand / or of the second electrode, seen in top view of therespective electrode. Especially, the active area c ontent mayrefer to the size of the second electrode. Alternat ively oradditionally, said active area content of the centr al regionis at most 30% or is at most 20% or is at most 15%.According to at least one embodiment, the intermedi ate areaamounts for at least 40% or for at least 60% or for at least70% or for at least 75% of the active area content.Alternatively or additionally, said active area con tent ofthe intermediate region is at most 94% or is at mos t 90% orisatmost85%.According to at least one embodiment, the edge area amountsforatleast3% orforatleast5% orforatleast 8% orforat least 10% of the active area content. Alternativ ely oradditionally,said active area contentofthe edge region is atmost30% orisatmost20% orisatmost15%. P2024,0573 WO N / P230208WO01 June 3,2025 -12 -It is possible that the above-recited area proporti ons applyfor only the central area, for only the intermediat e area,for only the edge area or for any combination of tw o of saidareas or for all three of said areas. In case of mo re thanthree areas,itispossible thatthe above-recited areaproportions apply for only one or two of said areas .According to at least one embodiment, the second el ectrode issmaller than the first electrode. Hence, seen in to p view ofthe first electrode, the first electrode may protru de allaround from the second electrode so that there is atermination region corresponding to an area ofthe first electrode notcovered bythe second electrode. Optionally,a size ofthe termination region isat least3%or at least 5% or at least 8% of the active area co ntent,seen in top view of the first electrode. Alternativ ely oradditionally, said size is at most 25% or at most 2 0% or atmost15% ofthe active area content.According to at least one embodiment, seen in top v iew of thefirst electrode, an overlap of the termination regi on and theintermediate area amounts for at least 5% or for at least 8%of the active area content. Alternatively or additi onally,said overlap amounts for at most 20% or for at most 15% orfor at most 12% of the active area content. It is p ossiblethat the termination region is distant from the cen tral area.According to at least one embodiment, the semicondu ctor layersequence becomes thinner in the termination region, forexample, starting from the second electrode or from startingnear the second electrode and towards the periphera l edge ofthe semiconductorlayersequence.Forexample,the P2024,0573 WO N / P230208WO01 June 3,2025 -13 -semiconductor layer sequence has the shape of a cyl inder witha truncated cone on top, or the shape of a prism wi th atruncated pyramid on top. It is possible that the f irstregion of the semiconductor layer sequence is unaff ected bythisbeveling.According to at least one embodiment, the power sem iconductordevice isa FRD ora RC-IGCT. Optionally,a diameterora mean diameterofthesemiconductor layer sequence is at least 2 cm or is at least3 cm or is at least 4 cm. Alternatively or addition ally, saiddiameter or mean diameter is at most 0.4 m or is at most 0.3m or is at most 0.2 m. For the mean diameter, refer red to asDm, it applies, for example: Dm = (4A / π) 0.5 , with A being thearea content of the semiconductor layer sequence, s een in topview ofthe firstelectrode.Optionally, the power semiconductor device is confi gured fora maximum voltage between the first electrode and t he secondelectrode, in a blocking state of the power semicon ductordevice, of at least 1.5 kV or of at least 3 kV or o f at least5 kV.Alternativelyoradditionally,said value is atmost30kV or is at most 20 kV or is at most 15 kV. The res pectivemaximum voltage defines, for example, a minimum thi ckness ofthe first and second regions, a thickness of a pass ivationlayer and / or distances of the first and second elec trodes tocurrent-leading components of the power semiconduct or device.According to at least one embodiment, the semicondu ctor layersequence is made of silicon, Si. However, the semic onductorlayer sequence can alternatively be of a wide-bandg apsemiconductor material like SiC, Ga 2O3 or GaN. P2024,0573 WO N / P230208WO01 June 3,2025 -14 -A power semiconductor device described herein is ex plained ingreater detail below by way of exemplary embodiment s withreference to the drawings. Elements which are the s ame in theindividual figures are indicated with the same refe rencenumerals. The relationships between the elements ar e notshown to scale, however, but rather individual elem ents maybe shown exaggeratedly large to assist in understan ding.In the figures:Figures 1 to 5 are schematic sectional views of exe mplaryembodiments of power semiconductor devices describe dherein,Figures 6 to 9 are schematic top views of exemplaryembodiments of power semiconductor devices describe dherein,Figure 10 are schematic top views of exemplary embo diments ofextensions of first regions for power semiconductordevicesdescribed herein,Figure 11 is a schematic top view of an exemplary e mbodimentofa structuring forpowersemiconductordevices described herein,and Figures12 and 13 are schematicrepresentationsof electric data of exemplary embodiments of power semiconducto rdevices described herein and of comparison devices.Figure 1 illustrates an exemplary embodiment of a p owersemiconductor device 1. The power semiconductor dev ice 1 P2024,0573 WO N / P230208WO01 June 3,2025 -15 -comprises a semiconductor layer sequence 3. The sem iconductorlayer sequence 3 has a first region 31 and a second region32. For example, the first region 31 is n-doped and n-conductive and the second region 32 isp-doped and p-conductive, or vice versa. In Figure 1, however, on ly halfthe semiconductorlayersequence 3 isshown.Thus, an axisRis an axis of mirror symmetry, for example. It is p ossiblethatthe axisR isan axisofrotation symmetry. Atthe firstregion 31,there isa firstelectrode 21 and atthe second region 32 there is a second electrode 22 . Theelectrodes 21, 22 are, for example, metallic electr odes. Itispossible thatthe firstregion 32 and the first electrode21 are congruent, seen in top view of the first ele ctrode 21.Optionally, the same may apply for the second regio n 32 andthe second electrode 22.A verticaldirection R is orientedperpendicular to the first electrode 21, for exampl e, andthusparallelwith the axisR.Moreover, the semiconductor layer sequence 3 includ es areverse layer44.The reverse layer44 isarranged between the firstelectrode 21 and the firstregion 31.It ispossible that the reverse layer 44 is in direct con tact withthe first electrode 21. If the first region 31 is n -conductive, then the reverse layer 44 is p-conducti ve.Atthe reverse layer44,there isa structuring 4. The structuring 4 isachieved byextensions5,51,52, 53 ofthefirst region 31. Hence, in the extensions 5, 51, 52 , 53, thefirst region 31 extends through the reverse layer 4 4 to thefirst electrode 21. The extensions 5, 51, 52, 53 ma y touchthe first electrode 21. As the extensions 5, 51, 52 , 53 canbe attributed to the first region 31, the extension s 5, 51, P2024,0573 WO N / P230208WO01 June 3,2025 -16 -52, 53 are of the same conduction type as the first region31.See extensions5,51,52,53 are,forexample, ofisland- shape,seen in top view ofthe firstelectrode 21. Thatis,adjacent extensions 5, 51, 52, 53 as illustrated in Figure 1may notbe connected with each other.Also seen in top view,the extensions 5, 51, 52, 53 may have different sha pes,compare also Figure 10 below.There are three areas 41, 42, 43 in which the exten sions 5,51, 52, 53 have different sizes and / or distances fr om eachother. Alternatively or additionally, the extension s 5, 51,52, 53 can have different area proportions in the a reas 41,42, 43. For example, ‘area proportion’ means a quot ient of anarea occupied by all the respective extensions 5, 5 1, 52, 53ofa specificone ofthe areas41,42,43 and area contentofsaid specific one of the areas 41, 42, 43. Thus, no t only thesizes of the extensions 5, 51, 52, 53 but also thei rdistancesfrom one anothermaybe differentin the areas41, 42,43.In a central one of the areas 41, there are first o nes of theextensions 51, and in an intermediate one of the ar eas 42,there are second onesofthe extensions52,and in an edgeone of the areas 43, there are third ones of the ex tensions53. The edge area 43 is next to a peripheral edge 4 6 of thesemiconductor layer sequence 3, and the central are a 41surrounds the axis R, for example. The first extens ions 51are larger and more distant from one another than t he secondextensions 52, and the second extensions 52 are lar ger andmore distant from one another than the third extens ions 53.Concerning an area content of the areas 41, 42, 43, thecentral area 41 and the edge area 43 are of about t he same P2024,0573 WO N / P230208WO01 June 3,2025 -17 -size whereas the intermediate area 42 is the larges t one ofthe areas 41, 42, 43, for example. An overall diame ter D ofthe semiconductor layer sequence 3 is, for example, at least90 mm and / oratmost150 mm.Optionally,the power semiconductordevice 1 isan FRD oran RC-IGCT.By way of example, the extensions 5, 51, 52, 53 are thickerthan the reverse layer44.Thus,the extensions5, 51,52,53may run into the first region 31. This means, for e xample,that in the extensions 5, 51, 52, 53 the semiconduc tor layersequence 3 has a higher maximum or mean doping conc entrationsthan in adjacentpartsofthe firstregion 31.In the embodiment of Figure 2 it is shown that in t heintermediate area 42 there is just one second exten sion 52that completely fills the intermediate area 42. Acc ordingly,an area proportion of said second extension 52 on t heintermediate area 42 is one or close to one, for ex ample, isatleast0.95 orisatleast0.98.Otherwise, the same as to Figure 1 may also apply t o Figure2,and vice versa.In Figure 3, an exemplary design of the semiconduct or layersequence 3 and of the electrodes 21, 22 is shown in moredetail.Forexample,the second region 32 includes a contact layer33 directlyatthe second electrode 22 and a bufferlayer 34 directly at the contact layer 33 and at th e firstregion 31. A maximum or mean doping concentration o f thecontact layer 33 is higher than of the buffer layer 34. Asthe doping is done by ion implantation, for example , in theindividual layers 33, 34, 36, 37, 44 of the semicon ductorlayer sequence 3 the doping concentration may not b e constant P2024,0573 WO N / P230208WO01 June 3,2025 -18 - butmayvaryaccording to a doping profile typical forion implantation.For example, a thickness or a design thickness of t he contactlayer 33 is at least 5 µm and at most 40 µm, depend ing on amaximum voltage between the electrodes 21, 22 the p owersemiconductordevice 1 isconfigured for.A dopingconcentration of the contact layer 33 directly at t he secondelectrode 22 is, for example, at least 1 x 10 17 cm -3 and / oris at most 1 x 10 19 cm -3 . A doping concentration of thebuffer layer 34 directly at the contact layer 33 is , forexample, at least 1 x 10 15 cm -3 and / or is at most1 x 10 17 cm -3 . The buffer layer 34 may optionally have athickness of at least 60 µm and / or of at most 180 µ m.Forexample,the firstregion 31 comprisesa drift region 35,a buffer layer 36 and a contact layer 37, the latte r beingcomposed of the extensions 5, 51, 52, 53. A thickne ss of thecontact layer 37 and, thus, of the extensions 5, 51 , 52, 53may be at least 5 µm and / or at most 40 µm, again de pendent onthe voltage class of the power semiconductor device 1. Adoping concentration of the contact layer 37 direct ly at thefirst electrode 21 is, for example, at least 1 x 10 20 cm -3and / or is at most 1 x 10 22 cm -3 . The buffer layer 36 may havea thicknessofatleast10 µm and / orofatmost50 µm and its doping concentration directlyatthe contactlayer 37 couldbe, for example, at least 1 x 10 15 cm -3 and / or is at most1 x 10 17 cm -3 .The thickest layer of the first region 31 is the dr ift region35. In the drift region 35, the doping concentratio n may beabout constant all along the vertical direction V a s the P2024,0573 WO N / P230208WO01 June 3,2025 -19 - driftregion 35 maystem from a substrate ofthesemiconductor layer sequence 3 so that no ion impla ntationfor doping may be required. The drift region 35 may have athicknessofatleast0.3 mm and / orofatmost1.2 mm,depending on the voltage class of the power semicon ductordevice 1. A maximum or mean doping concentration of the driftregion 35 is, for example, at least 1 x 10 12 cm -3 and / or isat most 1 x 10 14 cm -3 .A thickness of the reverse layer 44 is, for example , the sameas the thickness of the contact layer 37, or the re verselayer 44 is thinner than the thickness of the conta ct layer37. A minimum thickness of the reverse layer 44 is, forexample, at least 30% or at least 50& of the thickn ess of thecontact layer 37. The reverse layer 44 may directly adjointhe first electrode 21 and the buffer layer 36. For example,the reverse layer 44 is present all along the firstelectrode.In case ofan n-conductive firstregion 31,thereverse layer 44 has a p-doping concentration direc tly at thefirst electrode 21, for example, at least 1 x 10 17 cm -3and / or is at most 1 x 10 19 cm -3 . As the n-dopingconcentration of the contact layer 37 and, thus, of theextensions 5, 51, 52, 53 is higher than said p-dopi ng, in theextensions 5, 51, 52, 53 the reverse layer 44 is ef fectivelyn-conductive but is both p-doped and n-doped, for e xample.By way of example, the first and / or the second elec trode 21,22 can optionally be of multilayer-fashion. A first layer 61of the first electrode 21 comprises or is made of a metallike molybdenum,forexample.A second layer62 is made ofor comprisesexemplarilyaluminum and / orothermetals like copper,titanium and / ornickel.In particular,the firstlayer 61 is configured to be electrically conductiv ely P2024,0573 WO N / P230208WO01 June 3,2025 -20 - contacted externallyand the second layer62 isametallization. For example, the metallization is applied in amethod using a sputtering process or an evaporation process.The second electrode 22 can comprise a third layer 63 and afourth layer 64, being stacked above one another in theverticaldirection V.Forexample,the third layer 63comprises a metal which is different than a metal c omprisedby the fourth layer 64. The third layer 63 comprise s orconsists exemplarily aluminum and / or other metals l ikecopper, titanium, nickel, tungsten, platinum and / or gold andthe fourth layer 64 comprises or consists exemplari lymolybdenum.In particular,the third layer63 isametallization and the further layer 64 is configure d to beelectricallyconductivelycontacted externally.All these aspects with regard to the electrodes 21, 22 andthe semiconductor layer sequence 3 can individually or in anycombination apply for all other examples of the pow ersemiconductordevice 1. Otherwise,the same asto Figures1 and 2 mayalso applyto Figure 3,and vice versa. The example ofFigure 4 isbased on the embodiment ofFigure2, however, the same can apply for the embodiment o f Figure1, that is, can be the case for the intermediate ar ea 42being composed by the plurality of the relatively s mallsecond extensions52.According to Figure 4, the semiconductor layer sequ ence 3comprisesa termination region 45.The termination region 45is a region in which the second electrode 22 is not present. P2024,0573 WO N / P230208WO01 June 3,2025 -21 -The region below the second electrode 22 may be ref erred toasactive region 47 so thatan overallarea ofthesemiconductor layer sequence 3 is an area content o f theactive region 47 plus an area content of the termin ationregion 45. The termination region 45 comprises a be veling 8.The beveling 8 may start at a kink 81 at some dista nce fromthe second electrode 22. For example, said distance is atleast 0.1% or at least 0.3% of the diameter D and / o r is atmost 2% or is at most 1% of the diameter D. The kin k 81 is ata side of the second region 32 remote from the firs t region31.The beveling 8 may extend into the drift region 35, forexample,foratmost10% orforatmost20% ofthe thickness ofthe driftregion 35 into the latter,seen along thevertical direction V. Optionally, the beveling is o f linearshape,butothershapesare also possible.Further, the edge region 43 can extend into the act ive region47. Other than shown it is alternatively also possi ble thatthe edge region 43 is limited to the termination re gion 45,and the regions43,45 maybe congruent.Based on Figure 4, in the example of Figure 5 the b eveling 8starts directly at the second electrode 22. Moreove r, as anoption it is possible that the beveling 8 terminate s with thesecond region 22, seen along the vertical direction V.For example, in central region 41, seen in cross-se ction, awidth of individual sections the reverse regions 44 betweenadjacentextensions51 isbetween 0.5 mm and 3 mm, forexample, 2.0 mm. A spacing between adjacent section s is, forexample, between 0.5 mm and 2.5 mm, like 1.5 mm; th e spacing P2024,0573 WO N / P230208WO01 June 3,2025 -22 - correspondsto a width ofthe firstextensions51. Itispossible that the spacing exceeds the width, option ally by atleast a factor of 1.2 and / or by at most a factor of 2.If structured, like in Figure 1, in the intermediat e region42, seen in cross-section, the spacing is between 0 .3 mm and2 mm,typically0.8 mm,corresponding to the width ofthesecond extensions 52. The width of the sections, an d, thus,the distance between the extensions 52 is between 0 .2 mm and1 mm, like 0.4 mm. It is possible that the width of theextensions 52 exceeds the distance between the exte nsions 52,forexample,byatleasta factorof1.5 and / orby atmosta factorof2.5.In edge region 43, seen in cross-section, a width o f thesections, that is, a distance between the third ext ensions53, is between 0.05 mm and 0.5 mm, for example, 0.1 mm to 0.2mm. The same may apply for the width of the third e xtensions53. Hence, said distance and said width 60 µm may b e the sameor may differ by at most a factor of 1.3 or by at m ost afactorof1.1. These dimensionsofthe structuring 4 can applyin the sameway for all other embodiments, individually or in a nycombination.A corresponding top view the device 1 of Figure 5 c an be seenin Figure 6.Otherwise, the same as to Figures 1 to 3 may also a pply toFigures4 to 6,and vice versa.Especially,such a beveling 8 can be presentin the device ofFigure 1. P2024,0573 WO N / P230208WO01 June 3,2025 -23 - In Figures7 to 9,furtherexamplesofthe powersemiconductor devices 1 are shown. According to Fig ure 7, theintermediate area 42 hassome ofthe furtherfirst extensions 511.Forexample,the centralarea 41 maycomprise justonefirst extension 51, and the further first extension s 511 havea same size as the first extensions 51. For example , thereare at most 10 3 or at most 10 2 of the further firstextensions 511 in the intermediate area 42. It is p ossiblethat a number of the second extensions 52 exceed th e numberof the further first extensions 511 by at least a f actor of10 or by at least a factor of 10 2 or by at least a factor of103.In Figure 7, the further first extensions 511 exten d in across-like manner. In Figure 8, the further first e xtensions511 form a circle around the central area 41. In Fi gure 9 itisshown thatthe furtherfirstextensions511 are arrangedin a couple of straight rays emerging from the cent ral area41. For example, there are at least three and / or at most 15of such rays, like the three rays of Figure 9. With in therays, a distance between the further first extensio ns 511 canbe the same as the distance between the first exten sions 51in the central area 41, or the distance between the furtherfirstextensions511 can be larger.Otherwise, the same as to Figures 1 to 6 may also a pply toFigures7 to 9,and vice versa. In Figure 10,some examplesofbasicshapesofthe extensions5, 51, 52, 53 are illustrated in top view. These ex tensions 5can be present in all of the embodiments of the dev ice 1, inany combination. For example, all the extensions 5, 51, 52,53 of the respective device 1 are of the same basic shape as P2024,0573 WO N / P230208WO01 June 3,2025 -24 -is possible in Figure 1, or the first and third ext ensions51, 53 are of the same basic shape and the second e xtension52 is of ring-shape as in Figures 2, 4 or 5, for ex ample.For example, the extensions 5, 51, 52, 53 can be of circularshape, of hexagonal shape, of rectangular shape, of squareshape or of polygonal shape, like octagonal. Especi ally, theextensions5,51,52,53 are ofhexagonalshape.Otherwise, the same as to Figures 1 to 9 may also a pply toFigure 10,and vice versa.In Figure 11, another example of the power semicond uctordevice 1 is illustrated. In this case, there are mo re thanthree of the areas 41, 42, 43. For example, the int ermediatearea 42 is split into a first and a second intermed iate area421, 422. This option can be present in all other e xamples aswell.Further, in Figure 11 it is shown that the areas 41 , 42, 421,422, 43 does not necessarily need to be rotation sy mmetric.For example, one of the areas 422 may engage into a nother oneof the areas 421. This is possible in all other emb odiments,too. Finally,in Figure 11 the axisR isnotan axisof rotationsymmetry, but just a central axis. Hence, seen in t op viewthe semiconductor layer sequence 3 does not need to be ofcircular shape but can have other shapes as well, a spolygonalshapeslike being a hexagon.Thisoption aswell can applyforallotherembodiments. P2024,0573 WO N / P230208WO01 June 3,2025 -25 - Otherwise,the same asto Figures1 to 10 mayalso applyto Figure 11,and vice versa.In Figure 12 and 13, some electrical data is illust rated.Compared is a power semiconductor device 1 as descr ibedherein, having the first extensions 51 with a width of 1.4 mmand a distance of 1.0 mm in the central area 12 whi ch has asize of 12% of the active region 47 as shown in Fig ure 4. Theintermediate area 42 has the second extensions 52 w ith awidth of0.8 mm and a distance of0.4 mm,the size oftheintermediate area 42 is 0.8 of the active region 47 . In theedge area 43, there are the third extensions 53 wit h a widthand a distance of 0.16 mm. All the extensions 51, 5 2, 53 areof hexagonal shape, seen in top view. The semicondu ctor layersequence 3 isofthe design ofFigure 3.Thus,theembodiments of Figures 1, 3 and 4 are combined with eachother.In the first comparison device 91, there is no inte rmediatearea but a centrally arranged main area spans until the edgearea and has thus a size of about 92% of the active region47. The extensions of the first comparison device 9 1 in themain area are as the first extensions 51 of the pow ersemiconductor device 1 of the previous paragraph. T he secondcomparison device 92 corresponds to the first compa risondevice 91 but with the main extensions being of theconfiguration of the second extensions 52 of the po wersemiconductor device 1 of the previous paragraph. O therwise,the first and second comparison devices 91, 92 corr espond tothe power semiconductor device 1 of the previous pa ragraph.As can be seen from the diagram of Figure 12 showin g theforward voltage FV vs. the recovery energy Erec, by combining P2024,0573 WO N / P230208WO01 June 3,2025 -26 -the first and second extensions 51, 52 the recovery energyEreccan be reduced byabout7.5 percent,compared with thefirst comparison device 91. At the same time, see t herepresentation of the forward current IF vs. the pe ak voltageVP in Figure 13, the snap-off behavior can be impro ved.Hence, having the central area 41 and the intermedi ate area42 with both the first and second extensions 51, 52 offers animproved technological trade-off and overall improv edelectricalproperties. The componentsshown in the figuresfollow,unless indicatedotherwise, exemplarily in the specified sequence di rectly oneon top of the other. Components which are not in co ntact inthe figures are exemplarily spaced apart from one a nother. Iflines are drawn parallel to one another, the corres pondingsurfaces may be oriented in parallel with one anoth er.Likewise, unless indicated otherwise, the positions of thedrawn components relative to one another are correc tlyreproduced in the figures.The invention described here is not restricted by t hedescription on the basis of the exemplary embodimen ts.Rather, the invention encompasses any new feature a nd alsoany combination of features, which includes in part icular anycombination offeaturesin the patentclaims,even ifthisfeature or this combination itself is not explicitl yspecified in the patent claims or exemplary embodim ents.This patent application claims the priority of Euro peanpatent application 24187414.8, the disclosure cont ent ofwhich isherebyincorporated byreference. P2024,0573 WO N / P230208WO01 June 3,2025 -27 - ListofReference Signs 1 powersemiconductordevice 21 firstelectrode (cathode) 22 second electrode (anode) 3 semiconductorlayersequence31 first region of first conductivity type (n-doped )32 second region of second conductivity type (p-dop ed)33 second contactlayerdirectlyatthe anode 34 second bufferlayer 35 driftregion 36 firstbufferlayer 37 firstcontactlayer 4 structuring 41 centralarea 42 intermediate area 421 firstintermediate area 422 second intermediate area 43 edge area 44 reverse layerofthe second conductivitytype 45 termination region 46 peripheraledge 47 active region5 extension of the first region through the reverse layer51 firstextension511 first extension extending into the intermediate area52 second extension 53 third extension 61 firstlayer 62 second layer 63 third layer 64 fourth layer 7 passivation P2024,0573 WO N / P230208WO01 June 3,2025 -28 - 8 beveling 81 kink 91 firstcomparison device 92 second comparison deviceD / 2 half diameter of the semiconductor layer sequen ceErecrecoveryenergy IF forward current R axisofrotation symmetry V verticaldirection VF forward voltage VP peakvoltage

Claims

P2024,0573 WO N / P230208WO01 June 3,2025 -29 - PatentClaims 1.A powersemiconductordevice (1)comprising- a first electrode (21) and a second electrode (22 ), and-a semiconductorlayersequence (3), wherein- seen along a vertical direction (V), the semicond uctorlayer sequence (3) comprises a first region (31) of a firstconductivity type, a second region (32) adjacent to thesecond electrode (22) of a second conductivity type differentfrom the first conductivity type, and a reverse lay er (44) ofthe second conductivity type between the first elec trode (21)and the firstregion (31),- the first region (31) comprises a plurality of ex tensions(5, 51, 52, 53) running through the reverse layer ( 44) alongthe vertical direction (V) towards the first electr ode (21),- seen in top view of the first electrode (21), the reverselayer (44) comprises a central area (41) in which t heextensions (5, 51, 52, 53) have a first size, an in termediatearea (42) in which the extensions (5, 51, 52, 53) h ave asecond size, and an edge area (43) in which the ext ensions(5, 51, 52, 53) have a third size, and the first si ze isdifferent from the second size and the third size a nd thesecond size isdifferentfrom the third size. 2.The powersemiconductordevice (1)according to the preceding claim, wherein the firstelectrode (21)isa cathode,the second electrode (22)isan anode,the firstconductivity type isn-conductive and the second conductivity type is p-co nductive,wherein the reverse layer (44) is directly at the f irstelectrode (21) and the extensions (5, 51, 52, 53) t ouch thefirst electrode (21) and are in direct contact with theP2024,0573 WO N / P230208WO01 June 3,2025 -30 - reverse layer(44),wherein the first region (31) comprises a drift reg ion (35)which is the layer of the first region (31) being m ostdistant from the first electrode (21), and the drif t region(35) is in direct contact with the second region (3 2).3.The powersemiconductordevice (1)according to anyone of the preceding claims, wherein the centralarea (41)isofcircularshape and theintermediate area (42) and the edge area (43) are o f ring-shape,wherein the intermediate area (42) completely surro unds thecentral area (41) and the edge area (43) completely surroundsthe intermediate area (42). 4.The powersemiconductordevice (1)according to anyone of the preceding claims,wherein, seen in top view of the first electrode (3 1), theextensions (5, 51, 52, 53) are of island-shape so t hatdirectly at the first electrode (31) the extensions (5, 51,52, 53) are distant from each other and have at lea st one ofcircular, ring, triangular, square, rectangular, he xagonal orn-polygonal shape, in case of the n-polygonal shape withn ≥ 8. 5.The powersemiconductordevice (1)according to anyone of the preceding claims,wherein the reverse layer (44) is present all along the firstelectrode (21) and the extensions (5, 51, 52, 53) o verlap involume with the reverse layer(44),wherein a maximum doping concentration of the exten sions (5,51,52,53)exceedsa maximum doping concentration ofthe reverse layer(44)byatleasta factoroften.P2024,0573 WO N / P230208WO01 June 3,2025 -31 - 6.The powersemiconductordevice (1)according to anyone of the preceding claims, wherein the reverse layer(44)isthinnerthan the extensions (5,51,52,53),seen along the verticaldirection (V). 7.The powersemiconductordevice (1)according to anyone of the preceding claims,wherein first ones of the extensions (51) of the ce ntral area(41) having the first size are larger than second o nes of theextensions (52) of the intermediate area (42) havin g thesecond size,and the second onesofthe extensions (53)having the second size are larger than third ones o f theextensions (53) of the edge area (43) having the th ird size.8.The powersemiconductordevice (1)according to anyone of the preceding claims,wherein the power semiconductor device (1) is a fas t recoverydiode,FRD. 9.The powersemiconductordevice (1)according to anyone of the two preceding claims,wherein the first ones of the extensions (51) exten d into theintermediate area (42) but not into the edge area ( 43).

10. The power semiconductor device (1) according to any oneofthe preceding claims,wherein the intermediate area (42) directly adjoins thecentral area (41) and the edge area (43) directly a djoins theintermediate area (42),wherein the edge area (43) is an outermost region o f thereverse layer (44), seen in top view of the first e lectrodeP2024,0573 WO N / P230208WO01 June 3,2025 -32 -wherein the central area (41), the intermediate are a (42) andthe edge area (43) are continuous areas and the cen tral area(41) is a hole-free, uninterrupted area, seen in to p view ofthe firstelectrode (21).

11. The power semiconductor device (1) according to any oneofthe preceding claims, wherein the centralarea (41)amountsforatleast 3% and at most30% ofan active area contentwhich isa size ofthefirst electrode (21) and / or of the second electrode (22),wherein the intermediate area (42) amounts for at l east 40%and atmost94% ofthe active area content,and wherein the edge area (43)amountsforatleast3% and at most30% ofthe active area content.

12. The power semiconductor device (1) according to thepreceding claim,wherein the second electrode (22) is smaller than t he firstelectrode (21) so that, seen in top view, the first electrode(21) protrudes all around from the second electrode (22) sothat there is a termination region (45) correspondi ng to anarea of the first electrode (21) not covered by the secondelectrode (22), seen in top view of the first elect rode (21),wherein a size of the termination region (45) is at least 3%and at most 25% of the active area content, seen in top viewofthe firstelectrode (21).

13. The power semiconductor device (1) according to thepreceding claim,wherein, seen in top view of the first electrode (2 1), anoverlap of the termination region (45) and the inte rmediatearea (42) amounts for at least 5% and at most 20% o f theP2024,0573 WO N / P230208WO01 June 3,2025 -33 -active area content, and the termination region (45 ) isdistantfrom the centralarea (41).

14. The power semiconductor device (1) according to any oneofthe two preceding claims,wherein the semiconductor layer sequence (3) become s thinnerin the termination region (45) from the second elec trode (22)towards a peripheral edge (46) of the semiconductor layersequence (3).

15. The power semiconductor device (1) according to any oneofthe preceding claims,wherein a diameter (D) of the semiconductor layer s equence(3)isatleast3 cm and atmost0.3 m,wherein the power semiconductor device (1) is confi gured fora maximum voltage between the firstelectrode (21) and thesecond electrode (22) in a blocking state of the po wersemiconductordevice (1)ofatleast1.5 kV and of atmost30 kV,wherein the semiconductor layer sequence (3) is mad e ofsilicon.

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