semiconductor device containing field stop region

Abstract

Semiconductor device (100) comprising: a drift region (102) of a first conductivity type arranged between a first surface (104) and a second surface (106) of a semiconductor body (108); a first region (110) of the first conductivity type on the second surface (106); a second region (112) of a second conductivity type arranged adjacent to the first region (110) on the second surface (106); a field-stop region (114) of the first conductivity type arranged between the drift region (102) and the second surface (106); a first electrode (116) on the second surface (106), wherein the first electrode (116) is arranged directly adjacent to the first region (110) in a first part (1061) of the second surface (106) and to the second region (112) in a second part (1062) of the second surface (106). is;and wherein the field stop region (114) comprises a first subregion (1141) and a second subregion (1142) between the first subregion (1141) and the second surface (106), wherein over a predominant area of ​​the first part (1061) of the second surface (106) the second subregion (1142) is directly adjacent to the first region (110) and contains dopants of the second conductivity type that partially compensate for dopants of the first conductivity type, and wherein a concentration profile of the dopants of the second conductivity type in the second subregion (1142) of the field stop region (114) has a peak (P).

Description

TECHNICAL AREA The present disclosure relates to a semiconductor device, in particular a semiconductor device, e.g. a power semiconductor diode, which includes a field-stopping region. BACKGROUND The technological development of new generations of semiconductor devices, such as diodes or insulated-gate field-effect transistors (IGFETs) like metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs), aims to improve electrical device characteristics and reduce costs by miniaturizing device geometries. Exemplary semiconductor devices are known from German patent applications DE 10 2015 102 129 A1 and US 5 162 876 A. Although costs can be reduced by miniaturizing device geometries, a variety of trade-offs and challenges must be addressed when increasing device functionalities per unit area. In silicon power diodes, reducing the thickness of the semiconductor body can be advantageous in terms of reducing static and dynamic electrical losses. However, a reduction in thickness typically comes at the cost of, for example, reduced thermal performance.B. breakdown voltage and performance under cosmic radiation. Power diodes can therefore incorporate a fairly deep field-stopping region to provide sufficient softness during an electrical switching operation. The field-stopping region aims to protect a certain amount of charge carrier plasma so that these charges can carry the load current during one end of a reverse recovery, thus preventing a hard break or snap-off. This may require a certain depth and dose for the field-stopping region to prevent the electric field from reaching a rearward part of the device, e.g., a part near the cathode of a power diode. The field-stopping region can increase the maximum electric field at a given applied reverse recovery.This allows for a higher reverse bias voltage (at the same overall chip thickness) compared to a diode without a field-stopping region or with a very shallow field-stopping region. A higher electric field can decrease the breakdown voltage and increase the failure rate under cosmic radiation (FIT). There may be a desire to improve a semiconductor device to allow sufficient softness during a switching operation without increasing the chip thickness and without sacrificing the breakdown voltage. SUMMARY The problem is solved according to the invention by the teaching of the independent patent claims. Further developments are the subject of the dependent patent claims. The expert will recognize additional features and advantages upon reading the following detailed description and upon examining the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are enclosed to provide a further understanding of the embodiments and are incorporated into and form part of this description. The drawings illustrate examples of semiconductor devices and, together with the description, serve to explain the principles of the examples. Further examples are described in the following detailed description and the claims. Fig. 1 is a schematic cross-sectional view of a semiconductor device containing a field-stop region. Fig. 2 is a schematic graph to illustrate a doping concentration profile along a first lateral direction in a subregion of the field-stop region of Fig. 1 (along a section line AA' of Fig. 1). Fig. 3 is a schematic graph to illustrate a carrier mobility profile along a vertical direction y in a subregion of the field-stop region of Fig. 1 (along a section line BB' of Fig. 1).1) to illustrate. Figures 4, 5, 6 to 7 are schematic graphs to illustrate doping concentration profiles along section lines BB' and CC' of Figure 1. Figures 8 and 9 are schematic cross-sectional views to illustrate examples of field-stop regions of a semiconductor device. Figures 10A to 10D are schematic cross-sectional views to illustrate examples of a field-stop region of a semiconductor device with an embedded region. The following detailed description refers to the accompanying drawings, which form part thereof and show specific examples for illustrative purposes in which semiconductor substrates can be processed. It is understood that other examples may be used and structural or logical modifications may be made without departing from the scope of this disclosure. For example, features illustrated or described for one example may be used in or in connection with other examples to arrive at yet another example. It is intended that this disclosure includes such modifications and variations. The drawings are not to scale and are for illustrative purposes only. Corresponding elements are identified by the same reference numerals in the various drawings unless otherwise stated. The terms "have," "contain," "comprise," "exhibit," and the like are open-ended terms, indicating the presence of the identified structures, elements, or features, but not excluding the presence of additional elements or features. Indefinite and definite articles should encompass both the plural and the singular unless the context clearly indicates otherwise. The term "electrically connected" describes a permanent, low-resistance connection between electrically connected elements, for example, a direct contact between the elements in question or a low-resistance connection via a metal and / or a highly doped semiconductor material. A resistive contact is a non-rectifying electrical connection. For physical dimensions, specified ranges include the boundary values. For example, a range for a parameter y from a to b is read as a ≤ y ≤ b. The same applies to ranges with a boundary value such as "at most" and "at least". The term "on" should not be interpreted as meaning only "directly on". Rather, if an element is positioned "on" another element (e.g., a layer is "on" another layer or "on" a substrate), another component (e.g., another layer) can be positioned between the two elements (e.g., another layer can be positioned between a layer and a substrate if the layer is "on" the substrate). The first conductivity type can be an n-type, and the second conductivity type can be a p-type. Alternatively, the first conductivity type can be a p-type and the second conductivity type an n-type. When switching between conductivity types, for example, the positions of the anode and cathode of a power diode can be reversed. An example of a semiconductor device can include a drift region of a first conductivity type located between a first surface and a second surface of a semiconductor body. The semiconductor device can further include a first region of the first conductivity type on the second surface. Additionally, the semiconductor device can include a second region of a second conductivity type located adjacent to the first region on the second surface. A field-stopping region of the first conductivity type can be located between the drift region and the second surface. The semiconductor device can further include a first electrode on the second surface. The first electrode can be located directly adjacent to the first region in a first part of the second surface. Furthermore, the first electrode can be located directly adjacent to the second region in a second part of the second surface.The field stop region can comprise a first subregion and a second subregion between the first subregion and the second surface. Over a predominant portion of the first part of the second surface, the second subregion can directly adjoin the first region and can contain dopants of the second conductivity type that partially compensate for dopants of the first conductivity type. According to some embodiments, within the entire extent of the second subregion, the dopants of the second conductivity type compensate for the dopants of the first conductivity type only partially, at most. For example, throughout the entire second subregion, the dopants of the second conductivity type only partially compensate for the dopants of the first conductivity type. For instance, the dopants of the second conductivity type do not substantially exceed the dopants of the first conductivity type in number anywhere within the second subregion.Another example of a semiconductor device can include a drift region of a first conductivity type located between a first surface and a second surface of a semiconductor body. The semiconductor device can further include a first region of the first conductivity type on the second surface. The semiconductor device can also include a second region of a second conductivity type on the second surface, directly adjacent to the first region. A field-stopping region of the first conductivity type can be located between the drift region and the second surface. The semiconductor device can further include a first electrode on the second surface. The first electrode can be located directly adjacent to the first region in a first part of the second surface. Furthermore, the first electrode can be located directly adjacent to the second region in a second part of the second surface.The field-stop region can comprise a first subregion and a second subregion between the first subregion and the second surface. Over a predominant portion of the first part of the second surface, the second subregion can directly adjoin the first region and can include an embedded region of a second conductivity type integrated within the second subregion of the field-stop region, where the dopants of the second conductivity type exceed the dopants of the first conductivity type in number. The embedded region is electrically connected to the second region. For example, the embedded region can at least partially adjoin the second region.The embedded region can, for example, border the second region in a lateral direction, and / or a laterally overlapping region of the embedded region can border the second region in a vertical direction, with the overlapping region being formed by a region of the embedded region that laterally overlaps the second region. To provide the electrical connection, a continuous path of the second conductivity type can exist between the embedded region and the second region. The embedded region can, for example, be laterally homogeneous. Alternatively, the embedded region can be laterally structured, with the extent to which the dopants of the second conductivity type exceed the dopants of the first conductivity type in number varying along a significant portion of the embedded region, for example, at least 20%, at least 30%, or at least 40% of the lateral extent of the embedded region. The embedded region can, for example, have at least one ignition region with a lower level of dopants of the second conductivity type compared to other regions of the embedded region. Alternatively, the embedded region can be intermittent, with an interrupted region providing the ignition region. In both examples, the ignition region can extend along a lateral direction from the embedded region.be surrounded by or even bordering the other area of ​​the embedded territory. The semiconductor device can be, for example, an integrated circuit, a discrete semiconductor device, or a semiconductor module. The semiconductor device can be, or contain, a power semiconductor device, such as a vertical power semiconductor device with a load current flowing between the first and second surfaces. The semiconductor device can be, or contain, a power semiconductor diode. The power semiconductor device can be configured to conduct currents greater than 1 A, 10 A, or even 30 A, and can further be configured to block voltages between load terminals, such as between the cathode and anode of a diode, in the range of several hundred to several thousand volts, for example, 400 V, 650 V, 1.2 kV, 1.7 kV, 3.3 kV, 4.5 kV, 5.5 kV, 6 kV, 6.5 kV.The blocking voltage can, for example, correspond to a voltage class specified in a datasheet of the power semiconductor device. The semiconductor body may contain or consist of a semiconductor material from the elemental semiconductors of Group IV, a IV-IV compound semiconductor material, a III-V compound semiconductor material, or a II-VI compound semiconductor material. Examples of semiconductor materials from the elemental semiconductors of Group IV include silicon (Si) and germanium (Ge). Examples of IV-IV compound semiconductor materials include silicon carbide (SiC) and silicon germanium (SiGe). Examples of a III-V compound semiconductor material include gallium arsenide (GaAs), gallium nitride (GaN), gallium phosphide (GaP), indium phosphide (InP), indium gallium nitride (InGaN), and indium gallium arsenide (InGaAs). Examples of II-VI compound semiconductor materials include cadmium telluride (CdTe), mercury cadmium telluride (CdHgTe), and cadmium magnesium telluride (CdMgTe).For example, the semiconductor body may be, or may contain, a magnetic Czochraliski, MCZ, or fusion zone (FZ) substrate, or an epitaxially deposited silicon semiconductor body. For example, the first surface can be a front surface or top surface of the semiconductor device, and the second surface can be a back surface or rear surface of the semiconductor device. The semiconductor body can be attached to a conductor frame, for example, via the second surface. Bond pads can be arranged over the first surface of the semiconductor body, and bond wires can be bonded to the bond pads. In the drift region between the first and second surfaces, for example, the impurity or doping concentration can gradually increase or decrease with increasing distance from the first surface, at least in parts of its vertical extent. According to other examples, the impurity concentration in the drift region can be approximately uniform. For silicon-based diodes, the mean impurity concentration in the drift region can range from 5 × 10¹² cm⁻³ to 1 × 10¹⁵ cm⁻³, for example, in a range of 1 × 10¹³ cm⁻³ to 2 × 10¹⁴ cm⁻³. In the case of a SiC-based semiconductor device, the mean impurity concentration in the drift region can range from 5 × 10¹⁴ cm⁻³ to 1 × 10¹⁷ cm⁻³, for example, in a range of 1 × 10¹⁵ cm⁻³ to 2 × 10¹⁶ cm⁻³. The vertical extent of the drift region can be determined by voltage-blocking requirements, e.g., B. a specified voltage class, the vertical power semiconductor device depends on.When the vertical power semiconductor device is operated in reverse voltage mode, a space charge region may extend partially or completely through the drift region, depending on the reverse voltage applied to the vertical power semiconductor device. When the vertical power semiconductor device is operated at or near its specified maximum reverse voltage, the space charge region can reach or penetrate the field-stop region. The field-stop region is configured to prevent the space charge region from migrating further to the cathode or collector on the second surface of the semiconductor body. The field-stop region can be formed, for example, by one or a combination of dopants that can be introduced into the semiconductor body from the second surface. For instance, the field-stop region can contain hydrogen-related donors introduced by proton implantation and subsequent annealing.One or more ion implantation processes at different ion implantation tilt angles and / or ion implantation energies allow the doping concentration profile of the field-stop region to be tailored to the application requirements. The field-stop region can be unstructured, e.g., continuous without openings, relative to an active region of the semiconductor device, or relative to a region on the second surface that is covered by the first and second regions. In some examples, the field-stop region can be structured and can completely or partially cover the first region. Similarly, the field-stop region can be structured and can completely or partially cover the second region. For example, the field-stop region can be structured and completely cover the second region while partially covering the first region.The dopants of the second conductivity type in the second subregion of the field-stopping region can partially compensate for dopants of the first conductivity type. For example, dopants of the second conductivity type partially compensate for dopants of the first conductivity type if the number of dopants of the first conductivity type is greater than the number of dopants of the second conductivity type, and the excess number of dopants of the first conductivity type determines the effective doping concentration and the conductivity type of the respective region. Partial compensation of the doping in the second subregion of the field-stopping region can improve the softness of a diode by delaying the flow of charge carriers of the first conductivity type, e.g., electrons, towards the drift region, and by reducing the flow of charge carriers of the second conductivity type, e.g.,Holes are delayed from the second region towards the first region. This may be due to a reduction in carrier mobility caused by the additional charge carrier scattering resulting from the presence of the partially compensated dopants. The first region can, for example, be a cathode region. The first region, the field stop region, and the drift region can, for example, form a continuous region of the first conductivity type. The second region can interrupt the cathode region on the second surface. Similar to the cathode region on the second surface, the second region can also directly contact the first electrode on the second surface. The second region can improve softness by building up a temporary support plasma during backward recovery. The charge carriers of this temporary support plasma can, for example, prevent snap-off or detachment. The design of the second region, such as its doping profile, geometry, or dimensions, can be tailored to specific operating conditions. The second region can be laterally adjacent to the first region, for example, directly bordering it laterally, or it can be laterally separated from the first region by an intermediate region. The first electrode on the second surface can be a first load terminal L1, e.g., a cathode terminal of a diode, and can contain or consist of a conductive material or a combination of conductive materials, for example, a doped semiconductor material (e.g., a degenerate doped semiconductor material) such as doped polycrystalline silicon, metal, or a metal compound. The first load terminal L1 can also contain a combination of these materials, e.g., a lining or adhesive material and an electrode material. Examples of contact or electrode materials include one or more of titanium nitride (TiN) and tungsten (W), aluminum (Al), copper (Cu), alloys of aluminum or copper, e.g., AlSi, AlCu, or AlSiCu, nickel (Ni), titanium (Ti), tungsten (W), tantalum (Ta), silver (Ag), gold (Au), platinum (Pt), and palladium (Pd). The semiconductor device may, for example, include a second load terminal, such as the anode terminal of a diode. The second load terminal may be a contact surface or area and may be formed by an entire wiring layer or a portion thereof. For example, the wiring layer may correspond to a wiring plane of a wiring region above the first surface, with the one wiring plane of the wiring region being closest to the first surface in the case of multiple wiring planes. The wiring region may comprise one or more than one, such as two, three, four, or even more, wiring planes. Each wiring plane may be formed by a single or a stack of conductive layers, such as metal layer(s). The wiring planes may, for example, be lithographically structured. An interlayer dielectric may be placed between stacked wiring planes.A contact plug (contact plug) or contact line (contact lines) can be formed in openings in the interlayer dielectric to electrically connect parts, e.g., metal conductors or contact areas, of different wiring levels. For example, the contact area of ​​the second load electrode can be electrically connected to an anode region of each of a plurality of diode cells in the semiconductor body by contact plugs arranged between the anode region and the contact region of the second load electrode. For example, the semiconductor device can contain diode cells of a diode cell array. The diode cell array can be a one-dimensional or two-dimensional regular arrangement of a plurality of diode cells. For example, the plurality of diode cells of the diode cell array can be electrically connected in parallel. Anode regions of the plurality of diode cells of an IGBT transistor cell array can, for example, be electrically connected to one another. Likewise, cathode regions of the plurality of diode cells of the diode cell array can be electrically connected to one another, for example, by sharing a common cathode electrode. A diode cell of the diode cell array, or a part thereof, such as the anode region, can, for example, be designed in the shape of a strip, a polygon, a circle, or an oval. The second sub-area of ​​the field stop zone can, for example, directly border the first area across the entire first part of the second surface. Thus, the second sub-area can completely cover the first area. A lateral concentration profile of dopants of the second conductivity type and / or a lateral concentration profile of dopants of the first conductivity type can be constant, for example, in the second subregion of the field stop region over a predominant portion of the first part (1061) of the second surface. Thus, a lateral concentration profile of dopants of the second conductivity type can be constant over more than 50%, e.g., more than 60%, more than 70%, more than 80%, or more than 90% of the top surface of the first region. A lateral concentration profile of dopants of the second conductivity type can even be constant over the entire top surface of the first region. For example, the dopants of the second conductivity type partially compensate for at least 10%, 50%, or 80% of the dopants of the first conductivity type in at least one region of the second subregion of the field-stop region. The diode's softness can be adjusted within a certain range, for example, by varying the degree of partial compensation. A vertical concentration profile of the dopants of the second conductivity type can, for example, extend from within the second sub-area of ​​the field stop region to the second surface. For example, a vertical concentration profile of dopants of the second conductivity type along a predominant vertical extent of the second region may correspond to, or be identical to, a vertical concentration profile of dopants of the second conductivity type extending from the second subregion of the field stop region through the first region and to the second surface. Consequently, a vertical concentration profile of dopants of the second conductivity type constituting the second region may also be present in the first region and extend into the second subregion. The dopants of the second conductivity type in the second subregion may partially compensate for the dopants of the first conductivity type constituting the field stop region. For example, the carrier mobility in the second subregion of the field stop region is more than 10% or more than 20% lower than the carrier mobility in the first subregion of the field stop region. The carrier mobility can decrease, for example, with an increasing degree of partial compensation of the dopants of the first conductivity type by dopants of the second conductivity type. The concentration of dopants of the second conductivity type in a region of the second subregion of the field stop region can, for example, be greater than 1 × 10¹⁵ cm⁻³, greater than 1 × 10¹⁶ cm⁻³, or greater than 1 × 0¹⁷ cm⁻³. The concentration of dopants of the second conductivity type in the second subregion can, for example, decrease steadily towards the first surface. An effective concentration of dopants of the first conductivity type in the region of the second subregion of the field stop region can, for example, lie in a range between 2 × 10¹⁵ cm⁻³ and 5 × 10¹⁶ cm⁻³. The effective concentration can, for example, be a net doping concentration, which corresponds to an absolute value of the difference between electrically active n-type and electrically active p-type dopants. Each of the n-type and p-type dopants can, for example, contain one or more dopant types or dopant elements. A ratio of a concentration of dopants of the second conductivity type to a concentration of dopants of the first conductivity type can lie in a range of 0.1 to 0.9, or 0.1 to 0.5, or 0.1 to 0.2 in at least one region of the second subregion. For example, the dopants can be substitutional dopants. A vertical position where the concentration profile of the first conductivity-type dopants forming the field-stop region intersects a concentration profile of first conductivity-type dopants forming the first region can, for example, define the vertical extent of the first region to the second surface. For instance, the field-stop region dopants may include hydrogen-related donors, the first region dopants may include phosphorus, and the second conductivity-type dopants in the second subregion of the field-stop region may include boron. In this case, the first region can extend from the second surface to the vertical position where the phosphorus concentration profile and the hydrogen-related donor concentration profile intersect.Further towards the first surface, the boron dopants can partially compensate for the hydrogen-related donors in the second subregion of the field stop region to bring about a decrease in carrier mobility. According to another example, a vertical position where the concentration profile of the second conductivity-type dopants, which partially compensate for the first conductivity-type dopants within the second subregion of the field-stop region, intersects a concentration profile of first conductivity-type dopants forming the first region, can define the vertical extent of the first region to the second surface. For example, the field-stop region dopants may include hydrogen-related donors, the first region dopants may include phosphorus, and the second conductivity-type dopants in the second subregion of the field-stop region may include boron. In this case, the first region can extend from the second surface to the vertical position where the phosphorus concentration profile and the boron concentration profile intersect.Further towards the first surface, the boron dopants can outnumber the phosphorus dopants in the second subregion of the field stop region, in order to cause a decrease in carrier mobility. For example, a pn transition between the second region and the field stop region may be located closer to the second surface than a separation plane between the second subregion of the field stop region and the first region. The separation plane between the second subregion of the field stop region and the first region may, for instance, be located where a vertical doping concentration profile of the second subregion of the field stop region and a vertical doping concentration profile of the first region intersect. A separation plane between the second subregion of the field-stop region and the first region can, for example, be located closer to the second surface than a pn junction between the second region and the field-stop region. The second region can be formed, for example, by means of a masked ion implantation process using dopants of the second conductivity type. For example, the concentration profile of the second-conductivity-type dopants in the second subregion of the field-stop region may exhibit a peak. This peak could be a local or global maximum in the second subregion. For instance, the concentration profile of the second-conductivity-type dopants in the second subregion of the field-stop region may decrease continuously towards the first surface. In this case, the second-conductivity-type dopants in the second subregion could represent an extension of a thermally activated ion implantation or diffusion profile of second-conductivity-type dopants that constitute the second region and were introduced into the semiconductor body via an unmasked ion implantation or diffusion process.In some other cases, the concentration profile of the dopants of the second conductivity type in the second subregion of the field stop region decreases steadily from the tip towards the first surface and continues to decrease steadily, at least over a vertical range, towards the first region. In this case, the dopants of the second conductivity type in the second subregion can be established or defined by a thermally activated ion implantation profile of dopants of the second conductivity type, which is implanted at an ion implantation depth within the second subregion, and, for example, a different ion implantation or diffusion profile of dopants can form the second region. Functional or structural details described above with respect to the features of the semiconductor device shall apply equally to corresponding features of the method described below. A method for manufacturing a semiconductor device may include providing a semiconductor body containing a drift region of a first conductivity type, arranged between a first surface and a second surface of the semiconductor body. The method may further include forming a first region of the first conductivity type on the second surface. The method may also further include forming a second region of a second conductivity type on the second surface, adjacent to the first region. Finally, the method may further include forming a field-stop region of the first conductivity type, arranged between the drift region and the second surface.Furthermore, the method can include forming a first electrode on the second surface, wherein the first electrode is directly adjacent to the first region in a first part of the second surface and to the second region in a second part of the second surface. The field-stop region can comprise a first subregion and a second subregion between the first subregion and the second surface. Over a predominant portion of the first part of the second surface, the second subregion is directly adjacent to the first region and contains dopants of the second conductivity type, which partially compensate for dopants of the first conductivity type. For example, the formation of the second region can involve an unmasked ion implantation process and a second implantation process, whereby dopants for the formation of the first region and the dopants of the second conductivity type can be implanted through the same mask. In this case, dopants for the formation of the second region can be formed by means of an unmasked ion implantation process and / or a diffusion process that introduces the dopants not only into a region where the second region is being formed, but also into a region where the first region is to be formed or has already been formed. However, in the first region, the doping by the dopants of the first conductivity type counteracts the dopants of the second conductivity type that were introduced by the doping process of the second region.The mask for implanting the dopants of the first conductivity type, which form the first area, can be used to implant the dopants of the second conductivity type with an implantation depth within the second sub-area of ​​the field stop area. For example, dopants of the second conductivity type can be formed using an unmasked ion implantation process. Dopants for forming the first region can be implanted through a mask that differs from the mask used for implanting dopants of the second region. Examples and features described above and below can be combined. Functional and structural details described in relation to the examples above shall apply equally to the exemplary examples illustrated in the figures and further described below. Further examples of semiconductor devices are explained below in conjunction with the accompanying drawings. Functional and structural details described in relation to the examples above are intended to apply equally to the exemplary embodiments illustrated in the figures and described below. The conductivity type of the illustrated semiconductor regions can also be interchanged, i.e., an n-type is a p-type and a p-type is an n-type. Fig. 1 schematically and by way of example shows a section of a cross-sectional view of a semiconductor device 100, e.g., a power semiconductor diode. The schematic graphs of Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6 schematically and by way of example show graphs of concentration profiles or carrier mobility along vertical or lateral directions of intersection lines AA', BB', CC'. Referring to the schematic cross-sectional view of Fig. 1, the semiconductor device 100 includes an n-doped drift region 102 located between a first surface 104 and a second surface 106 of a semiconductor body 108, e.g., a silicon semiconductor substrate. A p-doped region 101, e.g., an anode region, is located on the first surface 104, which is oriented along a vertical direction y opposite the second surface 106. In the illustrated example, the anode region is a continuous region directly adjacent to the first surface 104. The anode region can comprise a plurality of anode subregions spaced laterally apart. The anode subregions can be laterally separated, for example, by trenches. The trenches can, for example, contain a trench electrode structure with a trench dielectric and a trench electrode. An n+-doped first region 110, e.g., a cathode region, is arranged on the second surface 106. A p+-doped second region 112 is arranged, e.g., along a first lateral direction x1 adjacent to the first region 110 on the second surface 106. A first electrode 116, e.g., a first load electrode or cathode electrode, is arranged, e.g., along a second vertical direction y, directly adjacent to the first region 110 in a first part 1061 of the second surface 106 on the second surface 106. The first electrode 116 is furthermore directly adjacent to the second region 112 in a second part 1062 of the second surface 106. An n-doped field stop region 114 is located between the drift region 102 and the second surface 106. The field stop region 114 comprises a first subregion 1141 and a second subregion 1142 between the first subregion 1141 and the second surface 106. Over a predominant portion of the first subregion 1141 of the second surface 106, the second subregion 1142 directly borders the first subregion 1141 and contains p-type dopants, e.g., one or more types of boron, aluminum, gallium, or indium in the case of a silicon semiconductor body, which partially compensate for the n-type doping of the field stop region 114. The n-doped field stop region 114 may contain hydrogen-related donors in the case of a silicon semiconductor body. The second sub-area 1142 of the field stop area 114 can directly border the first area 110 across the entire first part 1061 of the second surface 106. Thus, partial compensation of the n-type doping in the field stop area 114 can occur, for example, across the entire first area 110. The p-type dopants can partially compensate for at least 10%, at least 50%, or at least 80% of the n-type dopants in at least one region of the second sub-area 1142 of the field stop area 114. The schematic graph in Fig. 2 illustrates a concentration profile of p-type dopants in the second subregion 1142 along the first lateral direction x1 (intersection line AA') in Fig. 1. In the illustrated example, the concentration profile in the second subregion 1142 of the field stop region 114 is constant over a predominant area of ​​the first part 1061 of the second surface 106. This can be achieved, for example, by implanting the p-type dopants using an unmasked ion implantation process or by implanting the p-type dopants using the same mask that is used to implant the n-type dopants, e.g., phosphorus, to form the first region 110. The schematic graph in Fig. 3 illustrates a profile of a beam mobility µ along the vertical direction y (intersection line BB') in Fig. 1. The schematic graph illustrates an average beam mobility µ in each of the first region 110, the second subregion 1142 of the field stop region 114, and the first subregion 1141 of the field stop region 114. The beam mobility in the second subregion 1142 of the field stop region is, for example, more than 10% or more than 20% lower than the beam mobility µ in the first subregion 1141 of the field stop region 114. The schematic graph in Fig. 4 illustrates schematic doping and / or carrier concentration profiles along the vertical direction y of Fig. 1 (along the intersection line BB' of Fig. 1). The doping concentration profiles may refer to an electrically active doping concentration. Profile c1 is a concentration profile of an n-type doping, e.g., a phosphorus profile, that defines the first region 110. Profile c2 is a concentration profile of an n-type doping (e.g., measurable by secondary ion mass spectrometry, SIMS) or a charge carrier profile (e.g., measurable by diffusion resistance profiling, SRP), e.g., a hydrogen-related donor profile measurable by SRP, that defines the field stop region 114. The first region 110 extends from a vertical position y1, where profiles c1 and c3 intersect, to the second surface 106. Profile c3 is a p-type profile, e.g., a boron profile, that partially compensates for the n-type doping in the second subregion 1142 of the field stop region 114. For example, the concentration c3 in a region of the second subregion 1142 of the field stop region 114 can be greater than 1 × 10¹⁵ cm⁻³, greater than 1 × 10¹⁶ cm⁻³, or greater than 1 × 10¹⁷ cm⁻³. For example, a difference between c2 and c3, such as an effective or net doping concentration, in a region of the second subregion 1142 of the field stop region 114 can be, for example, in a range between 1 × 10¹⁴ cm⁻³ and 2 × 10¹⁶ cm⁻³. The net doping concentration can, for example, be a difference between electrically activated dopants of different conductivity types. In a specific example, the net doping concentration can be the absolute value of the concentration of the electrically activated dopants of the first conductivity type minus the concentration of the electrically activated dopants of the second conductivity type.The ratio of c2 to c3 can be in at least one area of ​​the second sub-area 1142 of field stop area 114 in a range of 0.1 to 0.9, 0.1 to 0.5, or 0.1 to 0.2. The dopants can be, for example, substitution dopants. The schematic graph of Fig. 5 illustrates schematic doping concentration profiles along the vertical direction y of Fig. 1 (along a section line CC' of Fig. 1). Profile c2 is the concentration profile of an n-type doping, also illustrated in Fig. 4, e.g., a profile of hydrogen-related donors, which defines the field stop region 114. Profile c4 is a p-type profile, e.g., a boron profile, which defines the second region 112. Profiles c3 and c4 can be identical (correspond to each other), e.g., formed by an unmasked ion implantation process for boron. The p-type profiles c3 and c4 can also differ from each other, e.g., by forming the second region 112 via masked ion implantation of p-type dopants and by forming the concentration profile c3 over the first region 110 via a masked or unmasked ion implantation process.Similarly, profile c3 in the second region 112 can be formed using an unmasked ion implantation process, and p-type dopants can also be introduced into the second subregion 1142 using a masked ion implantation process. Alternatively, profiles c3 and c4 can be formed, for example, using various masked ion implantation processes. The schematic graph of Fig. 6 illustrates schematic doping concentration profiles along the vertical direction y of Fig. 1 (along the intersection line BB' of Fig. 1). Profiles c1 and c2 are similar to the example illustrated in Fig. 4. Profile c3 differs from the example illustrated in Fig. 4 in that profile c3 has a local peak in the second sub-region 1142 and does not extend to the second surface 106. Thus, profile c3 can be used to define part of the second region 112. The schematic graph of Fig. 7 illustrates schematic doping concentration profiles along the vertical direction y of Fig. 1 (along the intersection line CC' of Fig. 1). Profile c2 is the concentration profile of an n-type doping, e.g., a hydrogen-related donor profile, also illustrated in Fig. 5, which defines the field stop region 114. Profile c4 is a p-type profile, also illustrated in Fig. 5, e.g., a boron profile, which defines the second region 112. Profiles c3 and c4 can be identical, e.g., generated by an unmasked ion implantation process for boron. The p-type profile c3 can be identical to the p-type profile c3 illustrated in Fig. 6. The p-type profile c3 can also be omitted over the second region 112, for example, by using a masked ion implantation process that limits the profile over the entire first region 110 or a part thereof. Similarly, profile c4 illustrated in Fig. 7 can also be used in the first region 110 (e.g., the graph of Fig. 6).6 added) may be present by forming the c4 profile, for example, by means of an unmasked ion implantation process. It is particularly worth mentioning that the profiles illustrated in the graphs will be overlapped in a finished device and can be thermally widened. The schematic cross-sectional view of Fig. 8 is an example of a semiconductor device 100 that can be formed by a method in which the p+-doped second region 112 is formed by an unmasked ion implantation process. The dopants of the n+-doped first region 110 and the p-type dopants for partial compensation of the n-doping in the second subregion 1142 are implanted through the same mask. In the illustrated example, a pn junction 120 between the second region 112 and the field-stop region 114 lies at the same vertical level as a separation plane 122 between the second subregion 1142 of the field-stop region 114 and the first region 110. In other examples, the plane 122 may be located closer to or farther from the second surface than the pn junction 120. The schematic cross-sectional view of Fig. 9 is an example of a semiconductor device 100 which can be formed by a method wherein p-type dopants are formed for partial compensation of the n-doping in the second subregion 1142 by means of an unmasked ion implantation process and wherein dopants for forming the first region 110 are implanted through a mask which differs from a mask used for implanting dopants of the second region 112. Figures 10A to 10D are schematic cross-sectional views to illustrate examples of field-stop regions of a semiconductor device with an embedded region. In the schematic cross-sectional view of Fig. 10A, the second subregion 1142 of the n-doped field-stop region 114 borders directly on the first region 110 and has a p-doped embedded region 115 of a second conductivity type, which is integrated into the second subregion 1142 of the field-stop region 114. In the embedded region 115, p-type dopants exceed n-type dopants in number. The embedded region 115 is electrically connected to the p+-doped second region 112. The example illustrated in Fig. 10B is similar to the example in Fig. 10A, but further includes an opening 1151 in the embedded region 115 above the n+-doped first region 110. The field-stop region 114 is electrically connected to the first electrode 116 via the opening 1151 in the embedded region 115. The examples illustrated in Fig. 10C , Fig. 10D differ from the examples illustrated in Fig. 10A and 10B in that part of the n-doped second subregion 1142 is arranged between the embedded region 115 and the n+-doped first region 110. The examples illustrated in the figures can be combined and can further be combined with other designs or configurations not illustrated in the figures but disclosed herein as examples. By varying the different configurations of the p-dopers in the second area, e.g., dose, vertical extent, lateral extent, ratio of c2 to c3, the diode's softness can be improved, thus enabling the semiconductor diode to be tailored to the requirements of applications. The aspects and features mentioned and described together with one or more of the previously described examples and figures can also be combined with one or more of the other examples to replace an identical feature of the other example or to additionally introduce the feature into the other example.

Claims

Semiconductor device (100) comprising: a drift region (102) of a first conductivity type arranged between a first surface (104) and a second surface (106) of a semiconductor body (108); a first region (110) of the first conductivity type on the second surface (106); a second region (112) of a second conductivity type arranged adjacent to the first region (110) on the second surface (106); a field-stop region (114) of the first conductivity type arranged between the drift region (102) and the second surface (106); a first electrode (116) on the second surface (106), wherein the first electrode (116) is arranged directly adjacent to the first region (110) in a first part (1061) of the second surface (106) and to the second region (112) in a second part (1062) of the second surface (106). is;and wherein the field stop region (114) comprises a first subregion (1141) and a second subregion (1142) between the first subregion (1141) and the second surface (106), wherein over a predominant area of ​​the first part (1061) of the second surface (106) the second subregion (1142) is directly adjacent to the first region (110) and contains dopants of the second conductivity type that partially compensate for dopants of the first conductivity type, and wherein a concentration profile of the dopants of the second conductivity type in the second subregion (1142) of the field stop region (114) exhibits a peak (P). Semiconductor device (100) according to the preceding claim, wherein the second sub-area (1142) of the field stop region (114) borders directly on the first region (110) over the entire first part (1061) of the second surface (106). Semiconductor device (100) according to one of the preceding claims, wherein a lateral concentration profile (clat) of the dopants of the second conductivity type and / or a lateral concentration profile of the dopants of the first conductivity type in the second sub-region (1142) of the field stop region (114) is constant over a predominant area of ​​the first part (1061) of the second surface (106). Semiconductor device (100) according to one of the preceding claims, wherein the dopants of the second conductivity type partially compensate at least 10% of the dopants of the first conductivity type in at least one region of the second sub-region (1142) of the field stop region (114). Semiconductor device (100) according to one of the preceding claims, wherein a vertical concentration profile (cv, cv1, cv2) of the dopants of the second conductivity type extends from within the second sub-area (1142) of the field stop region (114) to the second surface (106). Semiconductor device (100) according to claim 5, wherein a vertical concentration profile (cv, cv3, cv4) of dopants of the second conductivity type along a predominant vertical extent of the second region (112) corresponds to a vertical concentration profile of dopants (cv, cv1, cv2) of the second conductivity type extending from the second subregion (1142) of the field stop region (114) through the first region (110) and to the second surface (106). Semiconductor device (100) comprising: a drift region (102) of a first conductivity type arranged between a first surface (104) and a second surface (106) of a semiconductor body (108); a first region (110) of the first conductivity type on the second surface (106); a second region (112) of a second conductivity type arranged adjacent to the first region (110) on the second surface (106); a field-stop region (114) of the first conductivity type arranged between the drift region (102) and the second surface (106); a first electrode (116) on the second surface (106), wherein the first electrode (116) is arranged directly adjacent to the first region (110) in a first part (1061) of the second surface (106) and to the second region (112) in a second part (1062) of the second surface (106). is;and wherein the field stop region (114) comprises a first subregion (1141) and a second subregion (1142) between the first subregion (1141) and the second surface (106), wherein over a predominant area of ​​the first part (1061) of the second surface (106) the second subregion (1142) is directly adjacent to the first region (110) and has an embedded region (115) of a second conductivity type integrated into the second subregion (1142) of the field stop region (114), wherein in the embedded region (115) dopants of the second conductivity type exceed dopants of the first conductivity type in number, and wherein the embedded region (115) is electrically connected to the second region (112), and wherein a part of the second subregion (1142) having the first conductivity type is electrically connected to the first region (110). Semiconductor device (100) according to one of the preceding claims, wherein a carrier mobility in the second sub-area (1142) of the field stop region (114) is more than 10% lower than a carrier mobility in the first sub-area (1141) of the field stop region (114). Semiconductor device (100) according to one of the preceding claims, wherein a concentration of the dopants of the second conductivity type in a region of the second subregion (1142) of the field stop region (114) is greater than 1x1015cm-3. Semiconductor device (100) according to one of the preceding claims, wherein an effective concentration of dopants of the first conductivity type in the region of the second subregion (1142) of the field stop region (114) is in a range between 1×1014cm-3 and 2×1016cm-3. Semiconductor device (100) according to one of the preceding claims, wherein a vertical position in which the concentration profile of the dopants of the first conductivity type forming the first region intersects a concentration profile of dopants of the first conductivity type forming the field stop region defines the vertical extent of the first region (110) to the second surface (106). Semiconductor device (100) according to the preceding claim, wherein the dopants of the second conductivity type comprise boron, the dopants of the first conductivity type comprise phosphorus, and the field stop region (114) contains hydrogen-related donors. Semiconductor device (100) according to the preceding claim, wherein a pn junction between the second region (112) and the field stop region (114) is located closer to the second surface (106) than a separation plane between the second subregion (1142) of the field stop region (114) and the first region (110). Semiconductor device (100) according to one of claims 1 to 12, wherein a separation plane between the second subregion (1142) of the field-stop region (114) and the first region (110) is closer to the second surface (106) than a pn junction between the second region (112) and the field-stop region (114). A method for manufacturing a semiconductor device (100) comprising: providing a semiconductor body (108) containing a drift region (102) of a first conductivity type, arranged between a first surface (104) and a second surface (106) of the semiconductor body (108); forming a first region (110) of the first conductivity type on the second surface (106); forming a second region (112) of a second conductivity type, arranged adjacent to the first region (110), on the second surface; forming a field-stop region (114) of the first conductivity type, arranged between the drift region (102) and the second surface (106);a formation of a first electrode (116) on the second surface (106), wherein the first electrode (116) is arranged directly adjacent to the first region (110) in a first part (1061) of the second surface (106) and to the second region (112) in a second part (1062) of the second surface (106); and wherein the field stop region (114) comprises a first subregion (1141) and a second subregion (1142) between the first subregion (1141) and the second surface (106), wherein over a predominant area of ​​the first part (1061) of the second surface (106) the second subregion (1142) is directly adjacent to the first region (110) and contains dopants of the second conductivity type that partially compensate for dopants of the first conductivity type, and wherein a concentration profile of the dopants of the second conductivity type in the second subregion (1142) of the field stop region (114) exhibits a peak (P). The method according to the preceding claim, wherein forming the second region (112) comprises an unmasked ion implantation process and a second ion implantation process, wherein dopants for forming the first region (110) and the dopants of the second conductivity type are implanted through the same mask. The method of claim 15, wherein the dopants of the second conductivity type are formed by means of an unmasked ion implantation process and wherein dopants for forming the first region (110) are implanted through a mask which differs from a mask used for implanting dopants of the second region (112).

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