Semiconductor device containing field stop area

Abstract

Semiconductor device (100), comprising: an n-doped drift region (102) arranged between a first surface (104) and a second surface (106) of a semiconductor body (108); a p-doped first region (110) arranged on the second surface (106); an n-doped field stop area (112) located between the drift area (102) and the first area (110), wherein the field stop area (112) has: a first subregion (1121) and a second subregion (1122), wherein a pn transition (pn) separates the first region (110) and the first subregion (1121), and hydrogen-related donors in the first subregion (1121) and in the second subregion (1122), wherein a concentration (cn) of hydrogen-related donors along a first vertical extension (d1) of the first subregion (1121) increases steadily from the pn transition (pn) to a maximum value (M) and decreases steadily from the maximum value to a reference value (R) at a first transition (T1) between the first subregion (1121) and the second subregion (1122), wherein in a depth interval starting at a depth of 1 µm upstream of the first transition (T1) and ending at a depth of 1 µm downstream of the first transition, a vertical gradient of the concentration (cn) of hydrogen-related donors varies by at least a factor of 2, and wherein a second vertical extension (d2) of the second subregion (1122) ends at a second transition (T2) to the drift region (102), where the concentration (cn) of hydrogen-related donors is 10% of the reference value (R),and wherein a maximum concentration value in the second sub-area (1122) is at most 20% greater than the reference value (R), and wherein the first vertical extent (d1) lies in a range between 50% and 200% of the second vertical extent (d2).

Description

TECHNICAL AREA

[0001] The present disclosure relates to a semiconductor device, in particular to a semiconductor device containing a field-stop region. BACKGROUND

[0002] The technological development of new generations of semiconductor devices, such as diodes or insulated-gate field-effect transistors (IGFETs), including metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs), aims to improve electrical device characteristics and reduce costs by shrinking or miniaturizing device geometries. For example, reference is made to the disclosures in German patent applications DE 11 2015 006 059 T5, DE 10 2011 113 549 A1, DE 10 2015 107 085 A1, and DE 10 2017 117 991 A1. Although costs can be reduced by miniaturizing device geometries, numerous trade-offs and challenges must be addressed when expanding device functionalities per unit area.For example, reducing the thickness of the semiconductor body can be advantageous in terms of reducing static and dynamic electrical losses. However, thickness reduction typically comes at the cost of, for example, breakdown voltage and cosmic radiation performance. Semiconductor devices may therefore incorporate a fairly deep field-stopping region to provide sufficient softness during electrical switching. 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 the reverse recovery. By avoiding punch-through, the field-stopping region can increase the maximum electric field at a given applied reverse recovery.This allows for higher blocking bias (at the same overall chip thickness) compared to a semiconductor device 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 (FIT) under cosmic radiation.

[0003] There may be a desire to improve a semiconductor device to allow sufficient softness during a switching operation without increasing the chip thickness. SUMMARY

[0004] The invention is defined in the independent patent claims. Further developments are the subject of the dependent patent claims.

[0005] An example from the present disclosure relates to a semiconductor device. The semiconductor device includes an n-doped drift region arranged between a first surface and a second surface of a semiconductor body. The semiconductor device further includes a p-doped first region arranged on the second surface. The semiconductor device also includes an n-doped field-stopping region arranged between the drift region and the first region. The field-stopping region comprises a first subregion and a second subregion. A pn ​​junction separates the first region and the first subregion. Hydrogen-related donors are contained in the first subregion and in the second subregion.The concentration of hydrogen-related donors increases steadily along a first vertical extension of the first subregion from the pn junction to a maximum value and decreases steadily from this maximum value to a reference value at a first transition between the first and second subregions. A second vertical extension of the second subregion terminates at a second transition to the drift region, where the concentration of hydrogen-related donors is 10% of the reference value. A maximum concentration value in the second subregion is at most 20% greater than the reference value. In some embodiments, the maximum concentration value in the second subregion is lower than the reference value.

[0006] Another example from the present disclosure relates to a semiconductor device. The semiconductor device includes an n-doped drift region located between a first surface and a second surface of a semiconductor body. The semiconductor device further includes a p-doped first region located on the second surface. The semiconductor device also includes an n-doped field-stopping region located between the drift region and the first region. The field-stopping region comprises a first subregion and a second subregion. A pn ​​junction separates the first region and the first subregion. Hydrogen-related donors are contained in the first subregion and in the second subregion.The concentration of hydrogen-related donors increases steadily along a first vertical extension of the first subregion from the pn transition to a maximum value and decreases steadily from this maximum value to a reference value at a first transition between the first and second subregions. A second vertical extension of the second subregion ends at a second transition to the drift region, where the concentration of hydrogen-related donors is 10% of the reference value. The maximum value of a vertical gradient of a logarithmic-linear graph, in which the ordinate is a nonlinear logarithmic scale of the hydrogen-related donor concentration and the abscissa is a linear scale of depth along a vertical direction, is at least three times greater in the first subregion than in the second subregion.Alternatively or additionally, a maximum positive value of a vertical gradient of a log-linear graph, in which the ordinate is a non-linear logarithmic scale of the concentration of hydrogen-related donors and the abscissa is a linear scale of depth along a vertical direction, is at least three times greater in the first sub-area than in the second sub-area.

[0007] 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

[0008] The accompanying drawings are included 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. Figure 1 is a schematic cross-sectional view of a semiconductor device containing a field-stop region. Fig. Figures 2 to 4 are logarithmic-linear graphs to create a profile of doping concentration along a line AA' of Fig. 1 to illustrate. Fig. Figures 5 to 7 are graphs representing the gradient of the logarithmic-linear graphs of the Fig. 2 to 4 to illustrate. Fig. Figure 8 is a schematic cross-sectional view to illustrate an IGBT that has a field stop region as shown in Figure 8. Fig. 2 to 7 are described.

[0009] 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 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.

[0010] 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.

[0011] 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.

[0012] 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".

[0013] 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).

[0014] An example of a semiconductor device can include an n-doped drift region located between a first surface and a second surface of a semiconductor body. The semiconductor device can further include a p-doped first region located on the second surface. Additionally, the semiconductor device can include an n-doped field-stopping region located between the drift region and the first region. The field-stopping region can comprise a first subregion and a second subregion. A pn ​​junction can separate the first region and the first subregion. Hydrogen-related donors are located in the first subregion and in the second subregion.The concentration of hydrogen-related donors along a first vertical extension of the first subregion can increase steadily from the pn junction to a maximum value and decrease steadily from this maximum value to a reference value at a first transition between the first and second subregions. A second vertical extension of the second subregion can terminate at a second transition to the drift region, where the concentration of hydrogen-related donors is 10% of the reference value. Alternatively, the second vertical extension of the second subregion can terminate at a depth where the concentration of hydrogen-related donors falls below the donor concentration of the drift region. The donor concentration of the drift region could, for example, be the background doping concentration of a silicon semiconductor substrate or an epitaxial layer deposited on a substrate.A maximum concentration value in the second sub-area can be at most 20%, at most 15%, or at most 10% greater than the reference value.

[0015] For example, in a depth interval beginning at a depth of 1 µm before the first transition and ending at a depth of 1 µm after the first transition, a vertical gradient of the concentration of hydrogen-related donors varies by at least a factor of 2, or at least a factor of 4, or at least a factor of 10. For example, at the first transition, a vertical gradient of the concentration of hydrogen-related donors varies by at least a factor of 2, or at least a factor of 4, or at least a factor of 10 over a vertical distance of 500 nm. For example, the concentration of hydrogen-related donors may exhibit a minimum or a saddle point at the first transition. According to some embodiments, the gradient of the concentration of hydrogen-related donors at the first transition may therefore be zero.

[0016] The semiconductor device can be, for example, a trench transistor device or a planar transistor device with vertical current flow. The trench transistor could, for example, be an insulated-gate bipolar transistor (IGBT).

[0017] 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, for example, be mounted on a conductor frame 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.

[0018] 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).

[0019] The semiconductor device can, for example, contain transistor cells of a transistor cell array. The transistor cell array can be a one-dimensional or two-dimensional regular arrangement of a plurality of transistor cells. For example, the plurality of transistor cells of the transistor cell array can be electrically connected in parallel. For example, source or emitter regions of the plurality of transistor cells of an array of IGBT transistor cells can be electrically connected to each other. Likewise, collector regions of the plurality of transistor cells of an array of IGBT transistor cells can be electrically connected to each other. Gate electrodes of the plurality of transistor cells of an array of IGBT transistor cells can, for example, be electrically connected to each other. A transistor cell of the transistor cell array, or a part thereof, e.g.,The gate electrode can be designed, for example, in the shape of a strip, a polygon, a circle or an oval.

[0020] For example, the semiconductor device may include a first load electrode, such as a source or emitter electrode of an IGBT. The first load electrode may be a contact surface or region 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 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 can be arranged between stacked wiring levels. A contact plug (contact plug) or contact line (contact lines) can be formed in openings in the interlayer dielectric to electrically connect parts, such as metal conductors or contact areas, of different wiring levels. For example, the contact area of ​​the first load electrode can be electrically connected to a source or emitter region of each of the plurality of transistor cells in the semiconductor body by contact plugs arranged between the source region and the contact area of ​​the first load electrode.

[0021] Similar to the first load electrode, a second load electrode, such as a collector electrode of an IGBT, can be a contact area and may consist of an entire additional wiring layer or part thereof. For example, the additional wiring layer may correspond to a wiring plane of a wiring area above the second surface. Structural variations of the wiring area and / or the second load electrode above the second surface may be similar to the structural variations described above with respect to the wiring area and / or the first load electrode.

[0022] For example, the trench transistor device can be part of an integrated circuit or a discrete transistor device. The trench transistor device can be a power trench transistor device, such as a vertical power trench transistor device with a load current flowing between the first load electrode above the first surface of the semiconductor body and the second load electrode above the second surface. In the vertical transistor device, a load current can flow along the vertical direction perpendicular to the first and / or second surface. The transistor device can be configured to conduct currents greater than 1 A, 10 A, or even 30 A. The number of transistor cells in the transistor cell array, for example, can depend on the maximum load current.For example, the number of transistor cells in the transistor cell array may be greater than 100, greater than 1000, or even greater than 10000. The power transistor device may also be configured to block voltages between the load terminals, such as between the emitter and collector of an IGBT, of more than 10 V, 12 V, 60 V, 100 V, 400 V, 650 V, 1.2 kV, 1.7 kV, 3.3 kV, 4.5 kV, 5.5 kV, 6 kV, or 6.5 kV. The blocking voltage may, for example, correspond to a voltage class specified in a datasheet for the power semiconductor device. The blocking voltage of the transistor device may be set by impurity concentration and / or a vertical extent of a drift region in the semiconductor body. The doping concentration of the drift area can gradually increase or decrease with increasing distance from the first main surface, at least in areas or sections of its vertical extent.According to other examples, the impurity concentration in the drift region can be approximately uniform. For silicon-based power transistors, an average impurity concentration in the drift region can be between 2 × 10⁻⁶. 12 cm -3 and 1 × 10 17 cm -3 , for example in an area of ​​5 × 10 12 cm -3 up to 1 × 10 15 cm -3 or 2 × 10 14 cm -3 , lie. In some cases, the average impurity concentration in the drift region for silicon-based power transistors can be in the range of 1 × 10 . 15 cm -3 up to 1 × 10 17 cm -3The vertical extent of the drift region may depend on voltage blocking requirements, such as a specified voltage class, of the vertical power semiconductor device. When the vertical power semiconductor device is operated in voltage blocking mode, a space charge region may extend vertically, partially or completely, through the drift region, depending on the blocking voltage applied to the vertical power semiconductor device. If the vertical power semiconductor device is operated at or near the specified maximum blocking voltage, the space charge region may reach or penetrate the field-stop region, which is configured to prevent the space charge region from propagating further to a back-emitter-collector contact on the second major surface of the semiconductor body.For IGBTs, the drift region can be formed in this way using desired doping levels and with a desired thickness, while achieving a smooth switching behavior.

[0023] For example, the p-doped first region can be a collector or a back-emitter region. The p-doped first region can, for example, be directly adjacent to the second load electrode on the second surface of the semiconductor body. A maximum doping concentration of the p-doped first region can, for example, be greater than the maximum value in the first subregion. In some embodiments, the p-doped first region can be interrupted by one or more n-doped regions, which are also located on the second surface.

[0024] The pn transition between the first region and the first subregion can, for example, be at least partially shaped as a plane that is at least substantially parallel to the second main surface.

[0025] The semiconductor device containing the field-stop region, which comprises the first and second subregions described above, offers several technical advantages when device dimensions are reduced. For example, the sensitivity of the field-stop doping profiles to variations in the oxygen and carbon impurities in the wafer base material, such as CZ or, in particular, MCZ crystalline silicon, can be reduced by avoiding pronounced minima in the field-stop profile, since the region of minima is highly susceptible to the formation of donor-like carbon-oxygen-hydrogen complexes. Furthermore, the dynamic characteristics of the semiconductor device, such as softness or dU / dt or dI / dt characteristics, can be improved by reducing the ripple of the doping profile of the hydrogen-related donor-containing field-stop region.

[0026] Structural and functional details described above regarding features of the semiconductor device can equally apply to the corresponding features related to the examples below.

[0027] Another example of a semiconductor device can include an n-doped drift region located between a first surface and a second surface of a semiconductor body. The semiconductor device can further include a p-doped first region located on the second surface. Additionally, the semiconductor device can further include an n-doped field-stopping region located between the drift region and the first region. The field-stopping region can comprise a first subregion and a second subregion. A pn ​​junction separates the first region and the first subregion. Hydrogen-related donors are located in the first subregion and in the second subregion.The concentration of hydrogen-related donors along a first vertical extension of the first subregion can increase steadily from the pn transition to a maximum value and decrease steadily from the maximum value to a reference value at a first transition between the first and second subregions. A second vertical extension of the second subregion can terminate at a second transition to the drift region, where the concentration of hydrogen-related donors is 10% of the reference value. The maximum value of a vertical gradient of a log-linear graph, where the ordinate is a non-linear logarithmic scale of the hydrogen-related donor concentration and the abscissa is a linear scale of depth along a vertical direction, is at least three times greater in the first subregion than in the second subregion.In other exemplary embodiments, the maximum value of the vertical gradient in the first subregion can be at least twice, or at least four times, or at least six times, or even at least ten times greater than in the second subregion.

[0028] The aforementioned abscissa can be defined as follows: the depth scale can be oriented from the second surface, e.g., the back of the semiconductor device, towards the first surface, e.g., the front of the semiconductor device. In other words, the depth can increase along the abscissa with increasing distance from the second surface, e.g., the back of the semiconductor device. Both the first and second sub-regions can be located closer to the second surface than to the first surface; for example, the first and second sub-regions can be located closer to the back than to the front of the semiconductor device. Therefore, the vertical gradient can exhibit positive values, with the graph representing the concentration of hydrogen-related donors increasing as one moves along the abscissa from a position on the second surface to a position on the first surface.

[0029] The vertical gradient, for example, shows positive values ​​in the first vertical extension of the first subregion. In particular, the vertical gradient may exhibit a relative or even a global maximum within the first vertical extension of the first subregion. The vertical gradient may, for example, show positive and / or negative values ​​in the second subregion. Compared to all values ​​of the vertical gradient within the second subregion, the value of a relative or global maximum of the vertical gradient within the first vertical extension of the first subregion may be at least twice, at least three times, at least four times, at least six times, or even at least ten times greater.In another embodiment, a maximum value of the vertical gradient in the first subregion is at least three times greater than any value of the gradient in the second subregion, where the vertical gradient is the gradient of a log-linear graph in which the ordinate is a non-linear logarithmic scale of the concentration of hydrogen-related donors and the abscissa is a linear scale of depth along a vertical direction. The sign of the gradient can be taken into account when comparing the gradient values. Naturally, when considering the sign, a positive value is always greater than any negative value by an arbitrary factor. Therefore, in some embodiments, a maximum value of the vertical gradient in the first subregion is at least three times greater than any positive value of the gradient in the second subregion.

[0030] For example, in a depth interval beginning at a depth of 1 µm before the first transition and ending at a depth of 1 µm after the first transition, a vertical gradient of the hydrogen-related donor concentration varies by at least a factor of 2, or at least a factor of 4, or at least a factor of 10. For example, at the first transition, the vertical gradient of the hydrogen-related donor concentration varies by at least a factor of 2, or at least a factor of 4, or at least a factor of 10 over a vertical distance of 500 nm. The hydrogen-related donor concentration may, for example, exhibit a minimum or a saddle point at the first transition. Therefore, according to some embodiments, the gradient of the hydrogen-related donor concentration at the first transition may be zero.

[0031] For example, the average value of a vertical gradient of the logarithmic linear graph from the pn transition to the maximum value in the first subregion can be at least three times greater than the average value from the first transition to a peak in the second subregion.

[0032] The concentration of hydrogen-related donors decreases, for example, along at least 70% or at least 80% of the second vertical extent. For instance, the second subregion may contain at most two peaks and / or at most two minima.

[0033] The vertical gradient of the logarithmic-linear graph within the second subregion is, for example, less than 2×10 13 cm -3 / 100 nm. For example, the vertical gradient within the second subregion exceeds 2×10 13 cm -3 / 100 nm not. Falling edges of the vertical gradient, e.g., at the second transition, can, in contrast, show negative values, which are of course less than 2×10 13 cm -3 / 100 nm, regardless of the steepness of a falling edge. For example, all rising edges of the vertical gradient of the logarithmic-linear graph within the second subregion are less than 2×10 13 cm -3 / 100 nm. In one embodiment, the vertical gradient shows slight ripples within the second subregion, which 2×10 13 cm -3 / exceed 100 nm. In at least 90% or even 95% of the second subregion, for example, the vertical gradient can be less than 2×10 13 cm -3 / 100 nm.

[0034] For example, a vertical profile of the hydrogen-related donor concentration in the second subregion may exhibit two peaks. The hydrogen-related donor concentration at a minimum between the two peaks can be at most 40%, 35%, or 30% lower than the concentration at the peak with the lower peak concentration. For example, 30% or 20% lower means that the difference is less than 30% or 20%, respectively.

[0035] For example, a vertical profile of the hydrogen-related donor concentration in the second subregion may exhibit a single peak. A hydrogen-related donor concentration at a minimum between the single peak in the second subregion and the maximum value in the first subregion can be at most 30% or at most 20% lower than a concentration at the single peak.

[0036] A vertical profile of the hydrogen-related donor concentration in the second subregion may, for example, decrease steadily from the first transition to the second transition. The second subregion may be free of hydrogen-related donor concentration peaks. Alternatively, or additionally, the hydrogen-related donor concentration may reach its maximum value within the second subregion at the first transition. In other words, the hydrogen-related donor concentration can never be higher in the second subregion than at the first transition.

[0037] For example, the first vertical extent can be in a range between 15% and 200% or between 50% and 200% of the second vertical extent.

[0038] A vertical distance between the pn junction and a position of maximum value can, for example, be in a range between 0.5 µm and 4 µm, or between 0.5 µm and 3 µm, or between 0.5 µm and 2 µm. A dose of electrically active hydrogen-related donors between the pn junction and a position of maximum value can, for example, be in a range between 1 × 10 11 cm -2 and 2.5×10 12 cm -2 or between 2×10 11 cm -2 and 2.5×10 12 cm -2 lay.

[0039] The vertical distance between the pn junction and the second junction can, for example, be in a range between 6 µm and 20 µm, or between 7 µm and 15 µm, or between 8 µm and 11 µm. For example, the dose of hydrogen-related donors between the pn junction and the second junction can be in a range between 5 × 10 11 cm -2 and 3.5×10 12 cm -2or between 1×10 12 cm -2 and 3.5×10 12 cm -2 lay.

[0040] For example, a vertical distance between the pn transition and a position of the maximum value can be smaller than a vertical distance between the position of the maximum value and the first transition.

[0041] For example, the ratio of the maximum value to a maximum concentration of hydrogen-related donors in the second sub-area may be in a range of 3 to 50 or 3 to 20.

[0042] A ratio between a concentration of donors that are on C i O i H n-complexes, and a total donor concentration along at least 80% of the second vertical extent is, for example, less than 0.1. By reducing the ripple of the doping profile of the field-stop region, the sensitivity of the field-stop doping profiles to variations in oxygen and carbon defects in the wafer base material, e.g., CZ (Czochralski) silicon such as MCZ (magnetic CZ) crystalline silicon, can be reduced.

[0043] An example of a method for fabricating the semiconductor device described above as an example may involve forming the field-stop region by ion implantation of protons based on one ion implantation energy or based on two different ion implantation energies. The protons may be implanted at at least two different implantation angles, e.g., 2, 4, 8, 16, or 32 different implantation angles, for each ion implantation energy.

[0044] For example, a first implantation angle for proton ions can be smaller than a second implantation angle for proton ions. The first ion implantation dose of protons implanted at the first implantation angle can be lower than the second ion implantation dose of protons implanted at the second implantation angle.

[0045] For example, the ion implantation dose of protons can increase with increasing implantation angle for at least two different implantation angles.

[0046] Following ion implantation of protons, hydrogen-related donors, for example, are electrically activated by curing in a temperature range of 370°C to 430°C or from 380°C to 400°C or, more specifically, from 382°C to 395°C.

[0047] The examples and features described above and below can be combined.

[0048] Regarding the examples described above, the functional and structural details should apply equally to the exemplary examples illustrated in the figures and described below.

[0049] 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 further below. The conductivity type of the illustrated semiconductor regions can be interchanged; that is, an n-type can be a p-type and a p-type can be an n-type.

[0050] Fig. Figure 1 schematically and exemplarily shows a section of a cross-sectional view of a semiconductor device 100, e.g., an IGBT. The schematic graphical representations or graphs of the Fig. Figures 2 to 4 show schematic and exemplary logarithmic-linear concentration profiles of a p-doping cp and an n-doping cn.

[0051] Referring to the schematic cross-sectional view of Fig. 1 contains the semiconductor device 100 an n - -doped drift region 102, which is arranged between a first surface 104 and a second surface 106 of a semiconductor body 108, e.g. a silicon semiconductor substrate. A p + A doped first region 110, e.g., a collector or back-emitter region, is located on the second surface 106. An n-doped field stop region 112 is located between the drift region 102 and the first region 110. The field stop region 112 comprises a first subregion 1121 and a second subregion 1122. The first region 110 and the first subregion 1121 are separated by a pn junction. Hydrogen-related donors defined n-type conductivity in the first subregion 1121 and in the second subregion 1122.

[0052] Referring to the schematic graphs of the Fig. In equations 2 to 4, where the ordinate is a nonlinear logarithmic scale of the concentration cn of hydrogen-related donors and the abscissa is a linear scale of depth along a vertical direction y, the concentration cn of hydrogen-related donors along a first vertical extension d1 of the first subregion 1121 increases steadily from the pn transition pn to a maximum value M and decreases steadily from this maximum value to a reference value R at a first transition T1 between the first subregion 1121 and the second subregion 1122. A second vertical extension d2 of the second subregion 1122 ends at a second transition T2 to the drift region 102, where the concentration cn of hydrogen-related donors is 10% of the reference value R. A maximum concentration value in the second subregion 1122 is at most 20% greater than the reference value R.The second vertical extension d2 of the second subregion 1122 can also end at a depth where the concentration of hydrogen-related donors falls below a donor concentration of the drift region 102.

[0053] A vertical distance d3 between the pn junction pn and a position of maximum value M can be in a range between 0.5 µm and 4 µm. A vertical distance between the pn junction pn and the second junction T2 can be in a range between 6 µm and 20 µm. The vertical distance d3 between the pn junction pn and a position of maximum value M can be smaller than a vertical distance d4 between the position of maximum value M and the first junction T1.

[0054] In the Fig. In the illustrated example 2, the vertical profile of the concentration cn of hydrogen-related donors in the second subregion 1122 decreases steadily from the first transition T1 to the second transition T2. ​​No peaks are present in the second subregion 1122. The concentration cn of hydrogen-related donors decreases along at least 70% of the second vertical extension d2.

[0055] In the Fig. In the illustrated example 3, the vertical profile of the concentration cn of hydrogen-related donors in the second subregion 1122 shows a single peak P1.

[0056] In the Fig. In the illustrated example 4, the vertical profile of the concentration cn of the hydrogen-related donors in the second sub-area 1122 shows two peaks P1, P2.

[0057] Fig. 5 to 7 each refer to the profiles of the Fig. 2 to 4 and illustrate a vertical gradient of the logarithmic-linear graphs of the Fig. 2 to 4. A maximum value of the vertical gradient of the log-linear graph is at least three times greater in the first sub-area 1121 than in the second sub-area 1122, or is at least three times greater in the first sub-area 1121 than in a first half of the second sub-area 1122 that is closer to the second surface 106 than a second half. Furthermore, a maximum positive value of the vertical gradient of the log-linear graph is at least three times greater in the first sub-area 1121 than in the second sub-area 1122, or is at least three times greater in the first sub-area 1121 than in a first half of the second sub-area 1122 that is closer to the second surface 106 than a second half.

[0058] The field stop area 112 described with reference to the examples above can be divided into a Fig.Figure 8 illustrates the integration of a second electrode 114 on the second surface 106. The second electrode 114 is located directly adjacent to the first area 110. The second electrode 114 can be a collector electrode on a rear side or back face of the IGBT 101. For example, the second electrode 114 can be located on a chip carrier, such as a conductor frame.

[0059] Furthermore, the IGBT 101 contains a p-doped body region 116 and an n +The p-doped source or emitter region 118. The p-doped body region 116 is located between the first surface 104 and the drift region 102 and forms a pn junction 119 with the drift region 102. A first electrode 120, e.g., an emitter electrode E, is located on a front or top surface of the IGBT 101 and is electrically connected to the source and body regions 118, 116. The emitter electrode E can form a wiring region over the semiconductor body 108 or be part thereof. The wiring region can comprise one, two, three, or more wiring levels, which may contain structured or unstructured metal layers and interlayer dielectrics arranged between the structured or unstructured metal layers. Contact holes, for example, can electrically connect the different wiring levels.The IGBT 101 further comprises a gate trench structure 122, which includes a gate dielectric 1221 and a gate electrode 1222. The gate electrode is electrically connected to the gate terminal G.

[0060] The examples illustrated in the figures can be combined and can further be combined with other designs or configurations of the second region 112 that are not illustrated in the figures but are disclosed herein as examples. By varying different configurations of the first and second subregions of the field-stop region, for example, geometry, doping dose, vertical extent, softness, or dU / dt or dI / dt characteristics can be improved by reducing the ripple of the doping profile of the field-stop region, thereby enabling access to tailoring the semiconductor device to the requirements of the application.

[0061] 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.

[0062] Although specific embodiments are illustrated and described herein, it is obvious to the person skilled in the art that a multitude of alternative and / or equivalent designs can be substituted for the specific embodiments shown and described.

Claims

[1] Semiconductor device (100), comprising: an n-doped drift region (102) arranged between a first surface (104) and a second surface (106) of a semiconductor body (108); a p-doped first region (110) arranged on the second surface (106); an n-doped field stop area (112) located between the drift area (102) and the first area (110), wherein the field stop area (112) has: a first subregion (1121) and a second subregion (1122), wherein a pn transition (pn) separates the first region (110) and the first subregion (1121), and hydrogen-related donors in the first subregion (1121) and in the second subregion (1122), wherein a concentration (cn) of hydrogen-related donors along a first vertical extension (d1) of the first subregion (1121) increases steadily from the pn transition (pn) to a maximum value (M) and decreases steadily from the maximum value to a reference value (R) at a first transition (T1) between the first subregion (1121) and the second subregion (1122), wherein in a depth interval starting at a depth of 1 µm upstream of the first transition (T1) and ending at a depth of 1 µm downstream of the first transition, a vertical gradient of the concentration (cn) of hydrogen-related donors varies by at least a factor of 2, and wherein a second vertical extension (d2) of the second subregion (1122) ends at a second transition (T2) to the drift region (102), where the concentration (cn) of hydrogen-related donors is 10% of the reference value (R),and wherein a maximum concentration value in the second sub-area (1122) is at most 20% greater than the reference value (R), and wherein the first vertical extent (d1) lies in a range between 50% and 200% of the second vertical extent (d2). [2] Semiconductor device (100), comprising: an n-doped drift region (102) arranged between a first surface (104) and a second surface (106) of a semiconductor body (108); a p-doped first region (110) arranged on the second surface (106); an n-doped field stop area (112) located between the drift area (102) and the first area (110), wherein the field stop area (112) has: a first subregion (1121) and a second subregion (1122), wherein a pn transition (pn) separates the first region (110) and the first subregion (1121), and hydrogen-related donors in the first subregion (1121) and in the second subregion (1122), wherein a concentration (cn) of hydrogen-related donors along a first vertical extension (d1) of the first subregion (1121) increases steadily from the pn transition (pn) to a maximum value (M) and decreases steadily from the maximum value to a reference value (R) at a first transition (T1) between the first subregion (1121) and the second subregion (1122), wherein in a depth interval starting at a depth of 1 µm upstream of the first transition (T1) and ending at a depth of 1 µm downstream of the first transition, a vertical gradient of the concentration (cn) of hydrogen-related donors varies by at least a factor of 2, wherein a second vertical extension (d2) of the second subregion (1122) ends at a second transition (T2) to the drift region (102), where the concentration (cn) of hydrogen-related donors is 10% of the reference value (R), and wherein a maximum value of a vertical gradient of a logarithmic-linear graph,in which the ordinate is a nonlinear logarithmic scale of the concentration (cn) of the hydrogen-related donors and the abscissa is a linear scale of depth along a vertical direction, in the first subregion (1121) is at least three times larger than in the second subregion (1122), and wherein the first vertical extent (d1) lies in a range between 50% and 200% of the second vertical extent (d2). [3] Semiconductor device (100) according to the preceding claim, wherein an average value of the vertical gradient of the log-linear graph from the pn junction (pn) to the maximum value (M) in the first subregion (1121) is at least three times greater than from the first junction (T1) to a peak in the second subregion (1122). [4] Semiconductor device (100) according to the preceding claim, wherein - the concentration (cn) of hydrogen-related donors decreases along at least 70% of the second vertical extent (d2) and / or - all rising edges of the vertical gradient of the logarithmic-linear graph within the second subregion (1122) are less than 2×10 13 cm -3 / 100 nm are. [5] Semiconductor device (100) according to one of the preceding claims, wherein a vertical profile of the concentration (cn) of the hydrogen-related donors in the second subregion (1122) has two peaks. [6] Semiconductor device (100) according to any one of claims 1 to 4, wherein a vertical profile of the concentration (cn) of the hydrogen-related donors in the second subregion (1122) has a single peak. [7] Semiconductor device (100) according to one of claims 1 to 2, wherein a vertical profile of the concentration (cn) of the hydrogen-related donors in the second subregion (1122) decreases continuously from the first transition (T1) to the second transition (T2). [8] Semiconductor device (100) according to one of the preceding claims, wherein a vertical distance (d3) between the pn junction (pn) and a position of the maximum value (M) is in a range between 0.5 µm and 4 µm. [9] Semiconductor device (100) according to one of the preceding claims, wherein a vertical distance between the pn junction (pn) and the second junction (T2) is in a range between 6 µm and 20 µm. [10] Semiconductor device (100) according to one of the preceding claims, wherein a vertical distance (d3) between the pn junction (pn) and a position of the maximum value (M) is smaller than a vertical distance (d4) between the position of the maximum value (M) and the first junction (T1). [11] Semiconductor device (100) according to one of the preceding claims, wherein a ratio of the maximum value (M) to a maximum concentration (cn) of the hydrogen-related donors in the second sub-area (1122) is in a range of 2 to 50. [12] Method for manufacturing the semiconductor device (100) according to any one of the preceding claims, comprising: a formation of a field stop region (112) by means of ion implantation of protons based on one ion implantation energy or based on two different ion implantation energies with at least two different implantation angles for each ion implantation energy. [13] Method according to the preceding claim, wherein a first implantation angle for the ion implantation of protons is smaller than a second implantation angle for the ion implantation of protons and wherein a first ion implantation dose of the protons implanted under the first implantation angle is less than a second ion implantation dose of the protons implanted under the second implantation angle. [14] Method according to the preceding claim, wherein an ion implantation dose of protons increases with increasing implantation angle for the at least two different implantation angles. [15] Method according to one of the three preceding claims, wherein, after ion implantation of protons, hydrogen-related donors are electrically activated by curing in a temperature range of 380°C to 390°C.

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