Semiconductor device and method of manufacture thereof

Abstract

Semiconductor device (100) comprising a semiconductor substrate (10) having a top (21) and a bottom (23), the semiconductor device (100) further comprising: a drift region (18) of a first conductivity type provided on the semiconductor substrate (10); a base region (14) of a second conductivity type provided between the drift region (18) and the top (21); a high concentration region of the first conductivity type or the second conductivity type provided in contact with the bottom (23) in the semiconductor substrate (10);and a buffer region (20) of the first conductivity type provided between the high concentration region and the drift region (18), wherein the buffer region (20) has one or more donor concentration peaks whose donor concentration is higher than that of the drift region (18), wherein: a donor concentration of the drift region (18) over the entire drift region (18) in the depth direction connecting the top (21) and the bottom (23) is higher than a base doping concentration of the semiconductor substrate.;

Description

BACKGROUND 1. TECHNICAL AREA The present invention relates to a semiconductor device and a manufacturing method thereof. 2. RELATED AREA It is conventionally known that the implantation and diffusion of hydrogen in a semiconductor substrate causes lattice defects present in a diffusion region to bind the hydrogen to act as a donor (see, for example, patent documents 1 to 6). Patent document 1: WO 2016 / 204 227 A1Patent document 2: DE 11 2018 000 050 T5Patent document 3: DE 11 2010 004 241 T5Patent document 4: JP 2014 - 107 278 APatent document 5: US 2015 / 0 311 279 A1Patent document 6: DE 10 2015 101 124 A1 Preferably, the range of a donor region and its donor concentration, caused by bonding of the lattice defect and the hydrogen, can be precisely controlled. GENERAL DISCLOSURE To solve the problem described above, according to one aspect of the present invention, a semiconductor device according to claim 1 is created, comprising a semiconductor substrate containing a top and a bottom. Each concentration peak value can exhibit a downward slope, with the concentration value decreasing from the bottom towards the top. For the second hydrogen concentration peak value, the upward slope can be smaller than the downward slope. For the second donor concentration peak value, the upward slope can be smaller than the downward slope. The donor concentration distribution between the first and second depths may exhibit a flat region where the donor concentration is approximately constant. The length of this flat region in the depth direction may be 10% or more of the thickness of the semiconductor substrate in that depth direction. The donor concentration distribution between the first and second depths may exhibit a flat region where the donor concentration is approximately constant. The length of this flat region in the depth direction may be 10 µm or more. A minimum donor concentration in the flat region can be greater than a donor concentration of the semiconductor substrate. A minimum donor concentration between the first depth and the second depth can be greater than the donor concentration of the semiconductor substrate. The concentration value of the second hydrogen concentration peak can be lower than the concentration value of the first hydrogen concentration peak. The semiconductor device can include an N-type drift region located on the semiconductor substrate. The semiconductor device can include an emitter region located in contact with the top surface of the semiconductor substrate, wherein the emitter region has a higher donor concentration than the drift region. The semiconductor device can include a P-type base region located between the emitter region and the drift region. The semiconductor device can include a P-type collector region located in contact with the bottom surface of the semiconductor substrate. The semiconductor device can include an N-type buffer region located between the collector region and the drift region, wherein the buffer region has one or more donor concentration peaks with a higher donor concentration than the donor concentration in the drift region.The first donor concentration peak value can be the donor concentration peak value in the buffer region. The semiconductor device can include an accumulation region located between the base region and the drift region, wherein the accumulation region has one or more donor concentration peaks whose donor concentration is higher than in the drift region. The second donor concentration peak can be the donor concentration peak in the accumulation region. The accumulation area may contain the donor concentration peak value of a donor other than hydrogen in addition to the second donor concentration peak value. The second donor concentration peak value can be located between the buffer region and the accumulation region. The semiconductor device can include a gate trench section located at the top of the semiconductor substrate. The second donor concentration peak can be positioned between the bottom of the gate trench section and the top of the semiconductor substrate. The semiconductor device may include an active section provided in the semiconductor substrate. The semiconductor device may include an edge termination section configured to enclose the active section in a top view of the semiconductor substrate. The semiconductor substrate may include a passage region into which hydrogen, implanted at a position of the second hydrogen concentration peak value, has penetrated. The passage region provided in the edge termination section may be shorter in depth than the passage region provided in the active section, or the passage region need not be provided in the edge termination section. The semiconductor device can comprise a transistor section and a diode section provided on the semiconductor substrate. The through-band provided in the diode section can be shorter in depth than the through-band provided in the transistor section, or the through-band need not be provided in the diode section at all. The through-band provided in the transistor section may be shorter in depth than the through-band provided in the diode section, or the through-band need not be provided in the transistor section. The first depth may be contained within a span of 5 µm or less from the underside in the depth direction. A donor concentration at the first hydrogen concentration peak value can be in the range of 1 × 1015 / cm3 to 1 × 1017 / cm3. According to a second aspect of the present invention, a method for manufacturing the semiconductor device of the first aspect according to claim 27 is provided. During initial implantation, at least a minimum dose of hydrogen, determined by the diffusion coefficient of hydrogen in the semiconductor substrate and the second depth, can be implanted. The semiconductor substrate is a silicon substrate, where, assuming that the second depth from the bottom is x(cm), a hydrogen dose Q ( / cm2) at initial implantation can satisfy the following equation. During initial implantation, hydrogen can be introduced to the first depth through plasma doping. The underside of the semiconductor substrate can be ground after plasma doping. The underside of the semiconductor substrate can be laser annealed after plasma doping. Further aspects of the invention are the subject of the dependent claims, the drawings, and the description of exemplary embodiments. The present invention may also be a subcombination of the features described above. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of an example of a semiconductor device 100. Fig. 2 shows a hydrogen concentration distribution, a donor concentration distribution, and a vacancy error concentration distribution 175 in the depth direction at line AA of Fig. 1. Fig. 3A is a diagram illustrating a relationship between a first hydrogen concentration peak value 131 and a first donor concentration peak value 111. Fig. 3B is a diagram illustrating a relationship between a second hydrogen concentration peak value 141 and a second donor concentration peak value 121. Fig. 3C is a diagram illustrating a slope of an upward inclination 142. Fig. 4A is a diagram illustrating a further definition of a normalization of a slope of an upward inclination 112. Fig. 4B is a diagram illustrating a further definition of a normalization of a slope of an upward inclination 122.Figure 5 is a diagram illustrating a flat region 150. Figure 6 is a diagram illustrating an example arrangement of a semiconductor device 100. Figure 7 is a diagram showing an example of a carrier concentration distribution in the depth direction along line BB of Figure 6. Figure 8 is a diagram illustrating further examples of arrangements of a semiconductor device 100. Figure 9 is a diagram showing an example of a carrier concentration distribution in the depth direction along line CC of Figure 8. Figure 10 shows a hydrogen concentration distribution and a carrier concentration distribution in the depth direction along line AA of Figure 1. Figure 11 shows an exemplary arrangement of corresponding elements on a top surface 21 of a semiconductor substrate 10. Figure 12 illustrates a cross-sectional view of an example along cc' of Figure 11. Figure 13 shows further examples of an arrangement of a through-region 106.Figure 14 shows further examples of an arrangement of a through-region 106. Figure 15 shows further examples of an arrangement of a through-region 106. Figure 16A shows further examples of an arrangement of a through-region 106. Figure 16B shows further examples of an arrangement of a through-region 106. Figure 17A shows further examples of an arrangement of a through-region 106. Figure 17B shows further examples of an arrangement of a through-region 106. Figure 17C is a diagram illustrating a minimum film thickness M of a photoresist film 200 to prevent hydrogen ions from penetrating a semiconductor substrate 10. Figure 18A shows further examples of an arrangement of a through-region 106. Figure 18B shows further examples of an arrangement of a through-region 106. Figure 19 is a flowchart for forming a through-region 106 in a method for fabricating a semiconductor device 100.Figure 20 shows an example of a carrier concentration distribution in a semiconductor substrate 10 after a diffusion step S1904. Figure 21 shows a relationship between a diffusion coefficient D of hydrogen and a first dose Q. Figure 22 shows a relationship between a diffusion coefficient D and an annealing temperature T. Figure 23 shows a relationship between a diffusion depth of hydrogen and a first dose. Figure 24 shows a relationship between a diffusion coefficient D and a diffusion depth x. Figure 25 shows straight lines defining a minimum dose for each annealing temperature. Figure 26 shows a relationship between a second dose and a minimum dose of a first dose. Figure 27 is a diagram illustrating an example of a first depth Z1. Figure 28 shows another example of a donor concentration distribution and a chemical hydrogen concentration distribution in the depth direction of a semiconductor substrate 10.Figure 29 shows an example of a chemical hydrogen concentration distribution and a chemical argon concentration distribution near a first hydrogen concentration peak value 131. Figure 30 is a diagram illustrating further arrangement examples of a semiconductor device 100. Figure 31 shows an example of a carrier concentration distribution, a chemical hydrogen concentration distribution, and a chemical boron concentration distribution along line DD of Figure 30. Figure 32 shows an example of a carrier concentration distribution, a chemical hydrogen concentration distribution, and a chemical phosphorus concentration distribution along line EE of Figure 30. Figure 33 is a flowchart illustrating part of a process for manufacturing a semiconductor device 100. Figure 34 is a flowchart illustrating part of a process for manufacturing a semiconductor device 100.Figure 35 shows an example sequence of implanting hydrogen ions to a first depth Z1 and a second depth Z2 in a single step of forming structures on one side of a bottom surface. Figure 36 shows another example sequence of implanting hydrogen ions to a first depth Z1 and a second depth Z2 in a single step of forming structures on one side of a bottom surface. DESCRIPTION OF EXAMPLE FORMS OF EXECUTION The present invention will now be described by means of embodiments of the invention. As used herein, one side in a direction parallel to the depth direction of a semiconductor substrate is referred to as the "top," while the other side is referred to as the "bottom." One of the two principal surfaces of a substrate, layer, or other element is referred to as a top surface, while the other surface is referred to as a bottom surface. A "top" and a "bottom" direction are not limited to the direction of gravity or the direction in which the semiconductor device is mounted. As used herein, in some cases technical content can be described using vertical coordinate axes: an X-axis, Y-axis, and Z-axis. The vertical coordinate axes are intended solely to indicate the relative positions of components and are not intended to restrict them to a specific direction. For example, the Z-axis is not intended to be limited to indicating an elevation direction relative to the ground. It should be noted that a +Z-axis direction and a -Z-axis direction are opposite directions. When the Z-axis direction is described without specifying positive and negative signs, the direction means a direction parallel to both the +Z-axis and the -Z-axis. As used herein, a reference to "identical" or "equal" may contain an error due to variations in manufacturing or the like. The error may be, for example, within the range of 10%.As used herein, a chemical concentration refers to an impurity concentration measured regardless of any activation state. The chemical concentration can be measured, for example, by a secondary ion mass spectrometry (SIMS) method. In some cases, a concentration difference between a donor and an acceptor may be a higher concentration of either the donor or the acceptor. The concentration difference can be measured by a voltage / capacitance (CV) method. Furthermore, a carrier concentration measured by a resistance scattering (SR) method may be a concentration of either a donor or an acceptor. Additionally, if a concentration distribution of a donor or an acceptor exhibits a peak, the peak may represent the concentration of either the donor or an acceptor within that region.For example, if the concentration of a donor or an acceptor is approximately uniform in an area where the donor or acceptor is present, then the average concentration of a donor or an acceptor in that area can be a donor concentration or an acceptor concentration. As used herein, a doping concentration can denote the concentration of an impurity that has been transformed into a donor or an acceptor. Here, in some cases, a doping concentration can be defined as the difference between the concentrations of a donor and an acceptor (i.e., a net doping concentration). Furthermore, in some cases, a peak value of a doping concentration distribution within a doped region can be defined as the doping concentration in the doped region. As used herein, atoms / cm³ or ions / cm³ or / cm³ are used as a concentration unit per unit volume. This unit is used for the concentration of a donor or acceptor in a semiconductor substrate or for chemical concentration. Atoms / cm² or ions / cm² or / cm² are used as a concentration unit per unit area. This unit is used for the amount (a dose) of atoms or ions to be implanted into a substrate. The representation of atoms and ions may be omitted. Unless otherwise stated, the SI system of units is used here. Although length is represented using centimeters, calculations can be performed after converting to meters (m). Fig. 1 is a cross-sectional view of an example of a semiconductor device 100. The semiconductor device 100 comprises a semiconductor substrate 10. The semiconductor substrate 10 is a substrate made of a semiconductor material. As an example, the semiconductor substrate 10 is a silicon substrate. The semiconductor substrate 10 has a donor concentration, which is determined by impurities and the like that are introduced during manufacturing. In this example, one conductivity type of the semiconductor substrate 10 is the N-type. In some cases, a donor concentration in the semiconductor substrate 10 can be referred to here as a substrate concentration. The semiconductor substrate 10 has a top surface 21 and a bottom surface 23. The top surface 21 and the bottom surface 23 are two main surfaces of the semiconductor substrate 10. Here, axes perpendicular to each other in a plane parallel to the top surface 21 and the bottom surface 23 are the x-axis and the y-axis, and an axis perpendicular to the top surface 21 and the bottom surface 23 is the z-axis. Although semiconductor elements such as IGBTs or FWDs are formed in the semiconductor substrate 10, these element structures are omitted in Fig. 1. The semiconductor substrate 10 is implanted with hydrogen ions from one side of the bottom surface 23. In this example, hydrogen ions are protons. Hydrogen ions are implanted to at least two depths Z1 and Z2 in the depth direction (along the z-axis) of the semiconductor substrate 10. In this example, of the two depths, the one closer to the bottom surface 23 is the first depth Z1, and the other, which is deeper from the bottom surface 23 than the first depth Z1, is the second depth Z2. In Fig. 1, although implanted hydrogens are schematically represented by Xs, hydrogens are distributed around the implantation positions Z1 and Z2. The first depth Z1 can be located closer to the bottom surface 23 of the semiconductor substrate 10 in the depth direction. For example, the first depth Z1 can be located at half or less than the thickness of the semiconductor substrate 10 with respect to the bottom surface 23, or at one-quarter or less of the thickness of the semiconductor substrate 10. The second depth Z2 can be located closer to the top surface 21 of the semiconductor substrate 10 in the depth direction. For example, the second depth Z2 can be located at half or less than the thickness of the semiconductor substrate 10 with respect to the top surface 21, or at one-quarter or less of the thickness of the semiconductor substrate 10. However, the first depth Z1 and the second depth Z2 are not limited to these ranges. Hydrogen ions implanted to the second depth Z2 pass from the underside 23 through a passage 106 to the second depth Z2. Vacancy defects such as a vacancy (V) and a divature (VV) are generated due to the penetration of hydrogen ions in the passage 106. As used herein, a vacancy is intended to contain a divature unless otherwise specified. A vacancy density in the passage 106 can be adjusted by a hydrogen ion dose implanted to the second depth Z2, etc. Hydrogen implanted at depths Z1 and Z2 is diffused into the through-region 106 by heat-treating the semiconductor substrate 10 after hydrogen ions have been implanted. The vacancies (V), oxygen (O), and hydrogen (H) present in the through-region 106 are bound to form VOH defects. The VOH defects act as donors, providing electrons. This can cause the donor concentration in the through-region 106 to be higher than a donor concentration Db (or a specific resistance, a base doping concentration) during the fabrication of a semiconductor block that forms the basis of the semiconductor substrate 10. Accordingly, the donor concentration of the semiconductor substrate 10 can be easily adjusted depending on the properties that elements formed on the semiconductor substrate 10 should possess.It should be noted that, unless otherwise specified, both VOH errors that have a distribution similar to a chemical concentration distribution of hydrogen and VOH errors that are similar to a distribution of vacancy errors in the passage area 106 are referred to as a hydrogen donor or hydrogen as a donor. It should be noted that a dopant used to adjust a base doping concentration Db is a dopant added during the fabrication of the semiconductor block. For example, if the semiconductor block is silicon, N-type dopants might contain phosphorus, antimony, or arsenic, and P-type dopants might contain boron, aluminum, or similar elements. In the case of a composite semiconductor or an oxide semiconductor other than silicon, the corresponding dopants would be used. Furthermore, the process for fabricating the semiconductor block could be a zone melting process (FZ process), a Czochralski process (CZ process), or a Czochralski process with an applied magnetic field (MCZ process). Normally, the semiconductor substrate 10 should be manufactured with a base doping concentration Db that corresponds to the properties of the elements to be formed on the semiconductor substrate 10, including a nominal voltage or a breakdown voltage. However, according to the semiconductor device 100 shown in Fig. 1, the donor concentration of the semiconductor substrate 10 and, within the range of the through-band 106, can be partially adjusted during the manufacturing of the semiconductor device 100 by controlling a hydrogen ion dose and an implantation depth, making the donor concentration partially higher than the base doping concentration Db. Therefore, elements with predetermined nominal voltage or breakdown voltage properties can be formed even when using the semiconductor substrate 10 with a different base doping concentration.Furthermore, although the fluctuation of the donor concentration during the fabrication of the semiconductor substrate 10 is relatively high, the hydrogen ion dose can be controlled with relatively high accuracy. Thus, the concentration of vacancies (V) created by hydrogen ion implantation can be controlled with high accuracy, thereby enabling the precise control of the donor concentration in the transition range 106. Fig. 2 shows a hydrogen concentration distribution, a donor concentration distribution, and a vacancy error concentration distribution 175 in the depth direction at the AA line of Fig. 1. The horizontal axis of Fig. 2 indicates a depth position from the bottom 23, and the vertical axis indicates a hydrogen concentration per unit volume, a donor concentration per unit volume, and a vacancy error concentration per unit volume on a logarithmic axis. It should be noted that the vacancy error concentration distribution 175 is a distribution immediately after hydrogen ions have been ion-implanted to obtain a second hydrogen concentration distribution, which is discussed below. At the time of completion of the semiconductor device 100, vacancies are reduced or eliminated compared to the time immediately after ion implantation and exhibit a concentration distribution different from that shown in Fig. 2.The hydrogen concentration in Fig. 2 is a chemical concentration, measured, for example, by a SIMS method. The donor concentration in Fig. 2 is an electrically activated doping concentration, measured, for example, by a CV or SR method. In Fig. 2, dashed lines indicate the hydrogen concentration distribution and the vacancy error concentration distribution 175, and a solid line indicates the donor concentration distribution. The hydrogen concentration distribution has a first hydrogen concentration peak value of 131 and a second hydrogen concentration peak value of 141. The first hydrogen concentration peak value of 131 shows a local maximum value at the first depth Z1. The second hydrogen concentration peak value of 141 shows a local maximum value at the second depth Z2. The donor concentration distribution has a first donor concentration peak value 111 and a second donor concentration peak value 121. The first donor concentration peak value 111 exhibits a local maximum value at the first depth Z1. The second donor concentration peak value 121 exhibits a local maximum value at the second depth Z2. However, a position where the first donor concentration peak value 111 exhibits the local maximum value does not necessarily coincide exactly with the first depth Z1. For example, it can be seen that if a position where the first donor concentration peak value 111 exhibits the local maximum value is contained within a total width at half the maximum of the first hydrogen concentration peak value 131 with respect to the first depth Z1, then the first donor concentration peak value 111 is essentially located at the first depth Z1.Accordingly, it can be seen that if a position where the second donor concentration peak value 121 shows the local maximum value is contained in a total width at half the maximum of the second hydrogen concentration peak value 141 with respect to the second depth Z2, then the second donor concentration peak value 121 is essentially located at the second depth Z2. The vacancy error concentration distribution 175 has a first vacancy concentration peak value, corresponding to the first hydrogen concentration peak value 131, and a second vacancy concentration peak value (vacancy concentration peak value 171), corresponding to the second hydrogen concentration peak value 141. However, it should be noted that the first vacancy concentration peak value is omitted for the purposes of this presentation. The vacancy concentration peak value 171 shows a local maximum value at depth Zd2. Each concentration peak value has an upward slope, in which a concentration value increases, and a downward slope, in which a concentration value decreases from the bottom 23 towards the top 21 of the semiconductor substrate 10. In this example, the first hydrogen concentration peak value 131 has an upward slope 132 and a downward slope 133. The second hydrogen concentration peak value 141 has an upward slope 142 and a downward slope 143. The first donor concentration peak value 111 has an upward slope 112 and a downward slope 113. The second donor concentration peak value 121 has an upward slope 122 and a downward slope 123. The vacancy concentration peak value 171 has an upward slope 172 and a downward slope 173. The donors of the semiconductor substrate 10 include a donor that was already present in the semiconductor substrate 10 prior to hydrogen ion implantation, i.e., the base doping concentration (the concentration Db), a donor activated by the implanted hydrogen, and the VOH defects described above. For example, the fraction in which hydrogen is activated as a donor is approximately 1%. In a region within the transition area 106, located some distance from the first depth Z1 and the second depth Z2, the fraction of VOH defect donors corresponding to the vacancy defect concentration is higher than the fraction of VOH defect donors corresponding to the chemical hydrogen concentration, and the donor concentration is proportionally controlled by the vacancy defect concentration.VOH errors corresponding to chemical hydrogen concentration refer to VOH errors where the chemical hydrogen concentration is more dominant than the vacancy error concentration. Here, VOH faults, where the chemical hydrogen concentration distribution is dominant, mean the following: When vacancies, oxygen, and hydrogen cluster to form a VOH fault, it indicates that the chemical hydrogen concentration is considerably higher than the vacancy fault concentration, such that the donor concentration distribution through the VOH fault is similar to the chemical hydrogen concentration distribution. For example, at a certain depth and a depth near that depth, when the chemical hydrogen concentration is higher than the vacancy fault concentration, this results in a donor concentration distribution similar to that of the VOH faults where the chemical hydrogen concentration distribution is dominant. On the other hand, for VOH defects where the vacancy defect concentration distribution 175 is dominant, it indicates that the vacancy defect concentration is considerably higher than the chemical hydrogen concentration, such that the donor concentration distribution through the VOH defect is similar to the vacancy defect concentration distribution. As an example, at a certain depth and a depth near it, when the vacancy defect concentration is higher than the chemical hydrogen concentration, it can be said that this results in the donor concentration distribution of the VOH defects where the vacancy defect concentration distribution 175 is dominant. It is argued that in the passage region 106, with the exception of the first depth Z1 and the second depth Z2, vacancies (V, VV, etc.) created by the penetrating hydrogen are distributed with approximately a uniform concentration along the depth direction, as shown in Fig. 2. It is also argued that oxygen (O), which is implanted, for example, during the fabrication of the semiconductor substrate 10, is uniformly distributed along the depth direction. Furthermore, in the passage region 106, hydrogen diffuses from both sides of the depth direction at the first hydrogen concentration peak value 131 and at the second hydrogen concentration peak value 141, such that a sufficient amount of hydrogen is present. These form a flat donor distribution as the VOH defects. It is argued that near the second hydrogen concentration peak value 141, the vacancy defects formed by hydrogen ion implantation, particularly unsaturated binding sites, are filled by the implanted hydrogen. Accordingly, in some cases, the second depth Zd2 of the vacancy concentration peak value 171 may be positioned somewhat closer to the implantation surface of an ion implantation or the first hydrogen concentration peak value 131 than the second depth Z2 of the second hydrogen concentration peak value 141. This also applies to the first vacancy concentration peak value; however, the positional gap is very small compared to that between Z2 and Zd2, which is why it is omitted from the illustration. Therefore, in the passage area 106, except near the first depth Z1 and the second depth Z2, there is a shallow area 150 in which the VOH defects, which are intended to act as donors, are distributed approximately uniformly. The donor concentration distribution in the shallow area 150 is approximately constant in the depth direction. "The donor concentration is approximately constant in the depth direction" can refer to a condition in which, for example, areas where the difference between the maximum and minimum donor concentration is 50% or less of the maximum donor concentration are consecutive in the depth direction. The difference can be 30% or less, or 10% or less of the maximum donor concentration in these areas. Alternatively, with respect to the average concentration of the donor concentration distribution in a given depth-directed range, a value of the donor concentration distribution can lie within ±50%, ±30%, or ±10% of the average concentration of the donor concentration distribution. As an example, a given depth-directed range could be as follows. That is, assuming a length of ZL from the first depth Z1 to the second depth Z2, the range could be a segment of length 0.5 ZL between two points, each spaced 0.25 ZL from the center Zc between Z1 and Z2 to either the first depth Z1 or the second depth Z2. Depending on the length of the shallow area 150, a length in the given range could be 0.75 ZL, 0.3 ZL, or 0.9 ZL. The range within which the flat region 150 is defined can be controlled by the position of the second hydrogen concentration peak value 141. The flat region 150 is defined between the first hydrogen concentration peak value 131 and the second hydrogen concentration peak value 141. Additionally, the donor concentration within the flat region 150 can be controlled by the hydrogen ion dose at the second hydrogen concentration peak value 141. Increasing the hydrogen ion dose results in more vacancies (V) being generated in the transition region 106, and consequently, the donor concentration increases. Alternatively, if hydrogen ions are implanted at a position lower than the first hydrogen concentration peak value 131, the acceleration energy of the hydrogen ions can be increased to such an extent that hydrogen penetrates (permeates) the semiconductor substrate 10. This means that the second hydrogen concentration peak value 141 can be generated in such a way that it does not remain within the semiconductor substrate 10. In this way, the vacancy defect concentration can also be increased. On the other hand, if the acceleration energy is excessive, the substrate is damaged too severely during ion implantation, to such an extent that, in some cases, the flatness of the vacancy defect distribution in the through-region 106 cannot be guaranteed. Accordingly, the second hydrogen concentration peak value 141 can be positioned within the semiconductor substrate 10. Because the second hydrogen concentration peak value 141 is located at a position lower than the first hydrogen concentration peak value 131, the peak value tends to spread further than the first hydrogen concentration peak value 131. Similarly, the second donor concentration peak value 121 also tends to spread further than the first donor concentration peak value 111. That is, the second donor concentration peak value 121 tends to be a gentler peak value than the first donor concentration peak value 111. Furthermore, in this example, the concentration value of the first hydrogen concentration peak value 131 is greater than the concentration value of the second hydrogen concentration peak value 141. The concentration value of the first hydrogen concentration peak value 131 can be 10 times or more than the concentration value of the second hydrogen concentration peak value 141, or it can be 100 times or more than the concentration value of the second hydrogen concentration peak value 141. In other examples, the concentration value of the first hydrogen concentration peak value 131 can be less than or equal to the concentration value of the second hydrogen concentration peak value 141. In this example, since the concentration value of the first hydrogen concentration peak 131 is large, the amount of hydrogen activated as a donor at the first hydrogen concentration peak 131 is relatively large. That is, a proportion of VOH error donors in which the chemical hydrogen concentration distribution is more dominant than the vacancy error concentration distribution 175 will be high. In this case, the shape of the first donor concentration peak 111 is similar to that of the first hydrogen concentration peak 131. On the other hand, the concentration value of the second hydrogen concentration peak 141 is relatively small, and the amount of hydrogen activated as a donor at the second hydrogen concentration peak 141 is also relatively small. That is, the proportion of VOH error donors in which the vacancy error concentration distribution 175 is dominant will be relatively higher than the proportion of VOH error donors in which the chemical hydrogen concentration distribution is dominant. In this case, the similarity between the shapes of the second donor concentration peak 121 and the second hydrogen concentration peak 141 will be less than the similarity between the shapes of the first donor concentration peak 111 and the first hydrogen concentration peak 131.Since it is assumed that the VOH errors are distributed almost uniformly over the entire transmission range 106, the second donor concentration peak value 121 takes on an even gentler shape. Peak shape similarity can be a statement indicating that the smaller value is greater than the difference in the slope angles of the corresponding inclinations between the hydrogen concentration peak value and the donor concentration peak value. According to such an arrangement, the flat region 150 can be provided between the first depth Z1 and the second depth Z2. Because hydrogen diffuses from both sides of the depth direction to the through-region 106, the flat region 150 can be easily formed as a flat area in the depth direction. The length of the flat region 150 in the depth direction can be 10% or more, 30% or more, or 50% or more of the thickness of the semiconductor substrate 10 in the depth direction. Furthermore, the length of the flat region 150 in the depth direction can be 10 µm or more, 30 µm or more, 50 µm or more, or 100 µm or more. A minimum donor concentration in the flat region 150 can be greater than the base doping concentration Db of the semiconductor substrate 10. This means that the donor concentration in the flat region 150 can be higher than the base doping concentration Db across the entire flat region 150. A difference between the donor concentration in the flat region 150 and the base doping concentration Db of the semiconductor substrate 10 can be adjusted, for example, by adding a hydrogen dose at the second hydrogen concentration peak value 141. A minimum donor concentration between the first depth Z1 and the second depth Z2 can be greater than the base doping concentration of the semiconductor substrate 10. N-type regions can be sequentially provided between the first hydrogen concentration peak value 131 and the second hydrogen concentration peak value 141. Furthermore, a minimum donor concentration between the second depth Z2 and the bottom surface 23 of the semiconductor substrate 10 can be greater than the donor concentration of the semiconductor substrate 10. Fig. 3A is a diagram illustrating a relationship between a first hydrogen concentration peak value 131 and a first donor concentration peak value 111. In this example, a slant 114 of the upward slope 112 of the first donor concentration peak value 111 is normalized using a slant 134 of the upward slope 132 of the first hydrogen concentration peak value 131. As an example, normalization is a process in which the slant 114 is subdivided by the slant 134. An upward slope can be a slope between a position where the concentration exhibits a local maximum and a position where the concentration is a predetermined fraction of the local maximum. The predetermined fraction can be 80%, 50%, 10%, or 1%, or other fractions can be used. Additionally, for the first hydrogen concentration peak value 131 and the first donor concentration peak value 111, a slope of the concentration distribution between the first depth Z1 and the bottom surface 23 of the semiconductor substrate 10 can be used. In the example shown in Fig. 3A, the slope 134 of the first hydrogen concentration peak value 131 is given by (H1 - aH1) / (Z1 - Z3), and the slope 114 of the first donor concentration peak value 111 is given by (D1 - aD1) / (Z1 - Z4).H1 is a hydrogen concentration at the first depth Z1, D1 is a donor concentration at the first depth Z1, a is a predetermined fraction, Z3 is a depth where the hydrogen concentration at the upward slope 132 of the first hydrogen concentration peak value 131 aH1, and Z4 is a depth where the donor concentration at the upward slope 112 of the first donor concentration peak value 111 aD1. For example, a normalization of the slope 114 by the slope 134 is (D1 - aD1)(Z1 - Z3) / {(H1 - aH1)(Z1 - Z4)}. α is defined as a slope where the slope 114 is normalized by the slope 134. Fig. 3B is a diagram illustrating a relationship between a second hydrogen concentration peak value 141 and a second donor concentration peak value 121. In this example, a slope 124 of the upward inclination 122 of the second donor concentration peak value 121 is normalized using a slope 144 of the upward inclination 142 of the second hydrogen concentration peak value 141. In the example shown in Fig. 3B, the slope 144 of the second hydrogen concentration peak value 141 is given by (H2 - aH2) / (Z2 - Z5) and the slope 124 of the second donor concentration peak value 121 is given by (D2 - aD2) / (Zd2 - Z6). H2 is a hydrogen concentration at the second depth Z2, D2 is a donor concentration at the second depth Z2, a is a predetermined fraction, Z5 is a depth at which the hydrogen concentration in the upward slope 142 of the second hydrogen concentration peak value 141 is aH2, and Z6 is a depth at which the donor concentration in the upward slope 122 of the second donor concentration peak value 121 is aD2. A fraction “a” used to normalize the skew of the second donor concentration peak value 121 may be the same as, or different from, a fraction “a” used to normalize the skew of the first donor concentration peak value 111.For example, normalizing the skew 124 by the skew 144 is (D2 - aD2)(Z2 - Z5) / {(Zd2 - Z6)(H2 - aH2)}. β is defined as a skew where the skew 124 is normalized by the skew 144. The normalized slope β of the upward tilt 122 of the second donor concentration peak 121 is smaller than the normalized slope α of the upward tilt 112 of the first donor concentration peak 111. In other words, the second donor concentration peak 121 is a gentler peak than the first donor concentration peak 111 with respect to the hydrogen concentration peak. Implanting hydrogen ions to form such a second donor concentration peak 121 allows the flat region 150 to be formed. Furthermore, forming the second donor concentration peak 121 in such a gentle manner allows changes in donor concentration at an edge of the flat region 150 to be gradual.The normalized inclination β of the upward slope 122 of the second donor concentration peak value 121 can be one or less, 0.1 times or less, or 0.01 times or less of the normalized inclination α of the upward slope 112 of the first donor concentration peak value 111. Furthermore, the inclination 144 of the upward slope 142 of the second hydrogen concentration peak value 141 can be smaller than the inclination 145 of the downward slope 143. Because a concentration distribution of hydrogen ions implanted from the underside 23 to a deep position can follow its gentle shape on one side of the underside 23, comparing the inclination 144 of the upward slope 142 with the inclination 145 of the downward slope 143 could, in some cases, determine whether the hydrogen of the second hydrogen concentration peak value 141 was implanted from one side of the underside 23. The inclination 145 is given by (H₂ - aH₂) / (Z₇ - Z₂). The inclination 125 is given by (D₂ - aD₂) / (Z₇ - Z₂). It should be noted that, although the inclination 124 of the upward slope 122 of the second donor concentration peak value 121 is greater than the inclination 125 of the downward slope 123 in Fig.3B, as in the second hydrogen concentration peak value 141, the tilt 124 of the upward slope 122 of the second donor concentration peak value 121 may be smaller than the tilt 125 of the downward slope 123. Fig. 3C is a diagram illustrating the slope of an upward gradient 142. The slope of the upward gradient 142 can be viewed as follows. As shown in Fig. 3C, at the second hydrogen concentration peak 141, there is a width (a 10% total width) between two positions Z8 and Z9, where 10% (0.1 x H2) of the peak H2 concentration falls, FW10%M. From the points above the peak position Z2, where the hydrogen concentration is 0.1 x H2, the two positions Z8 and Z9 are the two closest to the peak position Z2. One of the two positions Z8 and Z9 that is closer to the first hydrogen concentration peak is Z8. The slope of the donor concentration at position Z8 is approximately flat. The slope of the hydrogen concentration at position Z8 is more than 100 times the slope of the donor concentration at position Z8.For example, the slant of the hydrogen concentration at position Z8 can be 100 times or more, or 1000 times or more, the slant of the donor concentration at position Z8. Fig. 4A is a diagram that illustrates a further definition of normalizing the slope of an upward inclination 112. For example, the following specification γ is introduced for normalizing the slope of the upward inclination 112. Although in the example of Fig. 3A, positions Z3 and Z4 are different, in this example they are the same position (Z3 = Z4). Here, position Z3 is a predetermined position. Position Z3 can be a position where the hydrogen concentration distribution and the donor concentration distribution in the upward inclination 132 and the upward inclination 112, respectively, are near the bottom with respect to position Z1. At position Z3, the hydrogen concentration is a × H1 and the donor concentration is b × D1. “a” is a ratio of the hydrogen concentration at position Z3 to the concentration H1 of the first hydrogen concentration peak 131 at position Z1.“b” is a ratio of the donor concentration at position Z3 to the concentration D1 of the first donor concentration peak value 111 at position Z1. Here, a skew of the hydrogen concentration ratio between section Z3 and section Z1, a skew of the donor concentration ratio between section Z3 and section Z1, and a skew ratio γ, which normalizes them, are introduced. The skew of the hydrogen concentration ratio between section Z3 and section Z1 is defined as (H1 / aH1) / (Z1 - Z3). Similarly, the skew of the donor concentration ratio between section Z3 and section Z1 is defined as (D1 / bD1) / (Z1 - Z3).The skew ratio γ, in which the skew of the donor concentration ratio between section Z3 and section Z1 is normalized by the skew of the hydrogen concentration ratio between section Z3 and section Z1, is defined as {(D1 / bD1 / (Z1 - Z3)} / {(H1 / aH1) / (Z1 - Z3)}. The normalized skew ratio γ becomes a simple ratio a / b by calculating the preceding equation. Fig. 4B is a diagram illustrating a further definition of the normalization of the slope angle of an upward inclination 122. For normalizing the slope angle of the upward inclination 122, a value ε similar to the value γ is introduced. Although in the example of Fig. 3B, positions Z5 and Z6 are different, in this example they are the same position (Z5 = Z6). Here, position Z5 is a predetermined position. Position Z5 can be a position where the hydrogen concentration distribution and the donor concentration distribution are located in the upward inclination 142 and the upward inclination 122, respectively, and near the bottom with respect to position Z2. At position Z5, the hydrogen concentration is c × H2 and the donor concentration is d × D2. “c” is a ratio of the hydrogen concentration at position Z5 to the concentration H2 of the second hydrogen concentration peak value 141 at position Z2."d" is a ratio of the donor concentration at position Z5 to the concentration D2 of the second donor concentration peak value 121 at position Z1. Here, a skew of the hydrogen concentration ratio between section Z5 and section Z2, a skew of the donor concentration ratio between section Z5 and section Z2, and a skew ratio ε, which normalizes them, are introduced. The skew of the hydrogen concentration ratio between section Z5 and section Z2 is defined as (H2 / cH2) / (Z2 - Z5). Similarly, the skew of the donor concentration ratio between section Z5 and section Z2 is defined as (D2 / dD2) / (Zd2 - Z5).The skew ratio ε, in which the skew of the donor concentration ratio between section Z5 and section Z2 is normalized by the skew of the hydrogen concentration ratio between section Z5 and section Z2, is defined as {(D2 / dD2 / (Z2 - Z5)} / {(H2 / cH2) / (Zd2 - Z5)}. The normalized skew ratio ε becomes a simple ratio (c / d){(Zd2 - Z5) / (Z2 - Z5)} by calculating the preceding equation. Furthermore, if Zd2 is sufficiently close to Z2, the skew ratio ε can be approximated to c / d. For example, if |Zd2 - Z2| is 10% or less of Z2 - Z5, the skew ratio ε can be approximated to c / d. For the first hydrogen concentration peak value 131 and the first donor concentration peak value 111, the hydrogen concentration distribution and the donor concentration distribution often have a similar shape. As used here, "have a similar shape" means that if, for example, the depth is a horizontal axis and a base-10 logarithm of the concentration is a vertical axis, the donor concentration distribution will show a distribution that reflects the hydrogen concentration distribution. That is, the donor concentration distribution will be a distribution that reflects the hydrogen concentration distribution by implanting hydrogen ions and further performing thermal annealing in a predetermined section between Z3 and Z1.For example, if the first hydrogen concentration peak value H1 is 131 1 × 10¹⁷ atoms / cm³ and the hydrogen concentration aH1 at position Z3 is 2 × 10¹⁶ atoms / cm³, then a is equal to 0.2. Conversely, if the first donor concentration peak value D1 is 111 1 × 10¹⁶ atoms / cm³ and the donor concentration bD1 at position Z3 is 2 × 10¹⁵ atoms / cm³, then b is equal to 0.2. Thus, the normalized skew ratio γ of a / b is equal to 1. In other words, the ratio a of the hydrogen concentration distribution and the ratio b of the donor concentration distribution at depth position Z1 near the bottom are approximately the same value and can be said to have a similar shape. On the other hand, for the second hydrogen concentration peak value 141 and the second donor concentration peak value 121, the hydrogen concentration distribution and the donor concentration distribution need not have a similar shape. That is, in a given section from Z5 to Z2, the donor concentration distribution does not have to reflect the hydrogen concentration distribution. For example, if H2 of the second hydrogen concentration peak value 141 is equal to 1 × 10¹⁶ atoms / cm³ and the hydrogen concentration cH2 at position Z5 is 1 × 10¹⁵ atoms / cm³, then c is equal to 0.1. Conversely, if D2 of the second donor concentration peak value 121 is 3 × 10¹⁴ atoms / cm³ and the donor concentration dD2 at position Z5 is 1.5 × 10¹⁴ atoms / cm³, then d is equal to 0.5. Thus, the normalized skew ratio ε from c / d is equal to 0.2.In other words, the ratio age c of the hydrogen concentration distribution is a value of 0.2 times the ratio d of the donor concentration distribution at position-depth position Z2, which is sufficiently deep from the bottom, and one can say that they show shapes that are far from similar. Comparing the normalized skew ratio γ with the normalized skew ratio ε, γ can be approximately 1 if the peak position of the hydrogen concentration distribution is near the bottom, and ε can be a value sufficiently smaller than 1 if the peak position of the hydrogen concentration distribution is sufficiently far from the bottom. That is, the normalized skew ratio ε can be smaller than the normalized skew ratio γ. Furthermore, the skew ratio ε can be 0.9 or less, 0.5 or less, or 0.2 or less. Alternatively, the skew ratio ε can be 0.1 or less, or 0.01 or less. Furthermore, as another example of the second donor concentration peak value 121, in some cases, due to reduced carrier mobility, a donor concentration calculated by a scattering drag, i.e., a carrier concentration at depth position Z2, may be reduced compared to a carrier concentration before or after depth position Z2. In such a case, an upward slope 122 becomes a downward slope, which is why the sign of d is negative. That is, d is a negative number with a magnitude of 1 or more. As a result, ε becomes a negative number. That is, the normalized slope ratio ε can be smaller than the normalized slope ratio γ. Moreover, the slope ratio ε can be 0.9 or less, 0 or less, or -1 or less. Alternatively, the slope ratio ε can be -10 or less, or -100 or less. It should be noted that the actual position of the second hydrogen concentration peak value 141 and the actual position of the second donor concentration peak value 121 can differ. Furthermore, the positions of the corresponding hydrogen concentration peak values ​​and the corresponding donor concentration peak values ​​need not exactly coincide for the first and second hydrogen concentration peak values ​​and the first and second donor concentration peak values. In such a case, where a hydrogen concentration peak value position and a donor concentration peak value position do not coincide, a hydrogen concentration peak value position can be Z1, and a donor concentration at Z1 can conveniently be a peak value position. In this way, a calculation according to the definition given above is possible. An important point in the description above is that the second hydrogen concentration peak value, 141, has a local maximum. In other words, it is important that the hydrogen concentration distribution has a local maximum at depth Z2. The fact that the second hydrogen concentration peak value, 141, has a local maximum allows for the comparison of the normalized inclination ratios discussed above. Figure 5 is a diagram illustrating a shallow region 150. As described above, the donor concentration distribution is approximately constant in the depth direction within the shallow region 150. The shallow region 150 is a section in which a range of donor concentrations between a predetermined maximum value "max" and a predetermined minimum value "min" is continuous in the depth direction. The maximum value "max" can be any maximum donor concentration within the region. The minimum value "min" can be 50%, 70%, or 90% of the maximum value "max". Alternatively, as discussed above, with respect to the average concentration of the donor concentration distribution within a given depth range, a value of the donor concentration distribution can lie within ±50%, ±30%, or ±10% of the average concentration of the donor concentration distribution. The given depth range can be the same as the previous one. Fig. 6 is a diagram illustrating an example arrangement of a semiconductor device 100. The semiconductor device 100 of this example acts as an IGBT. The semiconductor device 100 of this example comprises a semiconductor substrate 10, a dielectric interlayer film 38, an emitter electrode 52, and a collector electrode 54. The dielectric interlayer film 38 is formed such that it covers at least a portion of the top surface 21 of the semiconductor substrate 10. Through-holes, such as contact holes, are formed in the dielectric interlayer film 38. The contact holes expose the top surface 21 of the semiconductor substrate 10. The dielectric interlayer film 38 can be silicate glass, such as PSG, BPSG, and the like, and can be an oxide film, a nitride film, or the like. The emitter electrode 52 is formed on the top surface of the semiconductor substrate 10 and on the top surface of the dielectric interlayer film 38. The emitter electrode 52 is also formed in the contact hole and in contact with the top surface 21 of the semiconductor substrate 10, which is exposed through the contact hole. The collector electrode 54 is formed on the underside 23 of the semiconductor substrate 10. The collector electrode 54 can be in contact with the entire underside 23 of the semiconductor substrate 10. The emitter electrode 52 and the collector electrode 54 are made of a metallic material such as aluminum. In the semiconductor substrate 10 of this example, a drift region 18 of the N- type, an emitter region 12 of the N+ type, a base region 14 of the P type, an accumulation region 16 of the N+ type, a buffer region 20 of the N+ type and a collector region 22 of the P+ type are provided. The emitter area 12 is in contact with the top surface 21 of the semiconductor substrate 10 and has a higher donor concentration than the drift area 18. The emitter area 12 contains an N-type impurity, e.g., phosphorus. The base region 14 is located between the emitter region 12 and the drift region 18. The base region 14 contains a P-type impurity, e.g., boron. In one direction of extension (along the y-axis of Fig. 6) of the trench section, P-type contact areas (not shown) are included, arranged alternately with the emitter regions 12. The contact areas can be formed on the top surface 21 of the base region and can be deeper than the emitter regions 12. The contact areas prevent an IGBT from latching upon switch-off. The accumulation zone 16 is located between the base zone 14 and the drift zone 18 and has one or more donor concentration peaks where the donor concentration is higher than in the drift zone 18. The accumulation zone 16 may contain an N-type impurity such as phosphorus or may contain hydrogen. The collector region 22 is in contact with the underside 23 of the semiconductor substrate 10. The acceptor concentration in the collector region 22 can be higher than the acceptor concentration in the base regions 14. The collector region 22 can contain the same p-type impurity as the base regions 14 or a different p-type impurity. The buffer zone 20 is located between the collector zone 22 and the drift zone 18 and has one or more donor concentration peaks where the donor concentration is higher than in the drift zone 18. The buffer zone 20 contains an N-type impurity such as hydrogen. The buffer zone 20 can act as a field stop layer to prevent depletion layer scattering from one side of the bottom of the base zone 14 from reaching the collector zone 22. A gate trench section 40 extends through the top surface 21 of the semiconductor substrate 10, the emitter region 12, the base region 14, and the accumulation region 16 to the drift region 18. The accumulation region 16 of this example is located above the lower end of the gate trench section 40. The accumulation region 16 can be configured to cover the entire underside of the base region 14. Providing the accumulation region 16, which has a higher concentration than the drift region 18, between the drift region 18 and the base region 14 enhances the carrier injection improvement effect (IE effect) and thus reduces the initial stress on the IGBT. The gate trench section 40 comprises a gate trench, a dielectric gate film 42, and a conductive gate section 44, which is formed closer to the top surface of the semiconductor substrate 10. The dielectric gate film 42 is formed such that it covers the inner wall of the gate trench. The dielectric gate film 42 can be formed by oxidizing or nitriding the semiconductor of the inner wall of the gate trench. The conductive gate section 44 is formed deeper in the gate trench than the dielectric gate film 42. That is, the dielectric gate film 42 insulates the conductive gate section 44 and the semiconductor substrate 10. The conductive gate section 44 is formed from a conductive material such as polysilicon. The conductive gate section 44 includes a region opposite the base region 14 that engages the dielectric gate film 42. Although the gate trench section 40 of this cross-section is covered by the dielectric interlayer film 38 in the top surface of the semiconductor substrate 10, the conductive gate section 44 is connected to a gate electrode in other cross-sections. When a predetermined gate voltage is applied to the conductive gate section 44, an electron inversion layer channel is formed on an outer layer of the base region 14 for connection to the gate trench section 40. The first donor concentration peak value 111 can be located in buffer area 20. The second donor concentration peak value 121 can be located in an N-type region above buffer area 20. The second donor concentration peak value 121 can be located between buffer area 20 and accumulation area 16. In this example, the second donor concentration peak value 121 is located in drift area 18. The second donor concentration peak value 121 can be located below the lower end of gate trench section 40, in contact with the lower end of gate trench section 40, or above the lower end of gate trench section 40. Fig. 7 is a diagram showing an example of a carrier concentration distribution in the depth direction along line BB of Fig. 6. Fig. 7 shows a portion of a hydrogen concentration distribution. The vertical axis of Fig. 7 is a logarithmic axis. A carrier concentration distribution in the buffer region 20 of this example has several peak values ​​24, which are provided at different positions in the depth direction. The peak values ​​24 are donor concentration peak values. The peak values ​​24 may contain hydrogen as an impurity. Providing several peak values ​​24 can more effectively suppress the depletion layer from reaching the collector region 22. The first donor concentration peak value 111 can act as the peak values ​​24 in the buffer region 20. As an example, the first donor concentration peak value 111 among the multiple peak values ​​24 in the buffer region 20 can be considered the peak value furthest from the bottom 23 of the semiconductor substrate 10. The flat region 150 is located between the first donor concentration peak value 111 contained in the buffer region 20 and the second donor concentration peak value 121. Among the multiple peak values ​​24 in the buffer region 20, the first donor concentration peak value 111 may have a higher donor concentration than the peak value 24 furthest from the bottom 23. Increasing the concentration of the first donor concentration peak value 111 facilitates the formation of the shallow region 150, even if the first donor concentration peak value 111 and the second donor concentration peak value 121 are spaced apart. A chemical hydrogen concentration distribution may include one or more hydrogen concentration peak values ​​194 between the first depth Z1 and the bottom 23. The hydrogen concentration peak values ​​194 may be located in the buffer region 20, as discussed with reference to Fig. 6, etc. The hydrogen concentration peak values ​​194 may be located at the same depth position as the peak values ​​24. The accumulation region 16 of this example contains several peak values ​​25. The peak values ​​25 are donor concentration peak values. The second donor concentration peak value 121 is located closer to the bottom 23 than the accumulation region 16. A region of the base doping concentration Db (a base-doped region 180) of the substrate may be located between the second donor concentration peak value 121 and the accumulation region 16. In other examples, a donor concentration between the second donor concentration peak value 121 and the accumulation region 16 may be higher than the base doping concentration Db of the semiconductor substrate. Furthermore, the semiconductor device 100 can use an undoped substrate as the semiconductor substrate 10, whereby dopants such as phosphorus (P) are not completely incorporated into the semiconductor block during its fabrication. In this case, the base doping concentration Dn of the semiconductor substrate 10 is lower than the base doping concentration Db. In the example in Fig. 7, a region where the doping concentration is the base doping concentration Dn is an undoped region 181. The base doping concentration Dn of the undoped region 181, for example, lies in the range of 1 × 10¹⁰ atoms / cm³ to 5 × 10¹² atoms / cm³. The base doping concentration Dn can be at least 1 × 10¹¹ atoms / cm³. The base doping concentration Dn can be at most 5 × 10¹² atoms / cm³. It should be noted that any concentration here can be a value at room temperature.As an example of the value at room temperature, a value at 300 K (Kelvin) (approximately 26.9 degrees Celsius) can be used. Fig. 8 is a diagram illustrating further examples of the arrangement of a semiconductor device 100. The semiconductor device 100 of this example differs from the semiconductor device 100 described in Figs. 6 and 7 in that the second donor concentration peak value 121 (and the second hydrogen concentration peak value 141) are arranged in the accumulation region 16. The further arrangement can be the same as that of the semiconductor device 100 described in Figs. 6 and 7. Fig. 9 is a diagram showing an example of a carrier concentration distribution in the depth direction along line CC of Fig. 8. Fig. 9 also shows a portion of a hydrogen concentration distribution. The vertical axis of Fig. 9 is a logarithmic axis. A carrier concentration distribution in accumulation region 16 of this example has several peak values ​​located at different positions along the depth. These peak values ​​are donor concentration peaks. The peak values ​​in accumulation region 16 may contain hydrogen or phosphorus as an impurity. Providing multiple peak values ​​in accumulation region 16 can suppress displacement current to the gate trench section in a structure where the gate trench section and a placeholder trench section are located adjacent to each other (see, e.g., WO 2018 / 030440A1). The placeholder trench section comprises a structure similar to the gate trench section and is a trench section to which an emitter potential is applied. The second donor concentration peak value 121 of this example acts as one of the donor concentration peak values ​​in the accumulation region 16. As an example among the multiple peak values ​​in the accumulation region 16, the second donor concentration peak value 121 can act as a peak value that is furthest from the top surface 21 of the semiconductor substrate 10. The flat region 150 of this example is located between the first donor concentration peak value 111, which is contained in the buffer region 20, and the second donor concentration peak value 121, which is contained in the accumulation region 16. A donor concentration of the second donor concentration peak value 121 can be lower than, equal to, or higher than a donor concentration of the other peak values ​​25 in the buffer area 20. If the buffer area 20 has three or more peak values, the donor concentrations of the peak values ​​25, except for the second donor concentration peak value 121, can be equal. A donor concentration of the second donor concentration peak value 121 can be determined based on a donor concentration that the flat area 150 should have. The carrier concentration in drift region 18 of this example can be higher than the base doping concentration Db of the substrate over the entire depth direction. Such a structure can precisely control the total carrier concentration in drift region 18. The peak values ​​25, excluding the second donor concentration peak value 121, can be a peak value due to a donor other than hydrogen. For example, the peak values ​​25 represent a peak value where phosphorus acts as a donor. VOH errors are minimal due to the use of phosphorus as a donor, and this can easily control the donor concentration at the peak values ​​25 and the surrounding area with the phosphorus concentration. Furthermore, the width of the second donor concentration peak value 121 in the depth direction can be designed to be wider than the width of the peak values ​​25 in the depth direction. In this way, displacement current to the gate trench section can be further suppressed. Additionally, as shown in Fig. 9, a valley of a donor concentration distribution can exist between the second donor concentration peak value 121 and the peak value 25 in the accumulation region 16.Alternatively, as shown by the dashed lines between the two peak values ​​in Fig. 9, the donor concentration distribution in the accumulation area 16 can be a kink instead of a trough. Fig. 10 shows a hydrogen concentration distribution and a carrier concentration distribution in the depth direction along line AA of Fig. 1. The carrier concentration was measured by the SR method. Near a span (Z2) of the second hydrogen concentration peak value 141, slightly more errors occur than in the passage range 106. In some cases, residual errors that were not bound by hydrogen can cause a trough 151 in the carrier concentration distribution near the second depth Z2. In some cases, if the valley 151 is present, the calculated slope of the upward gradient 122 of the second donor concentration peak value 121 may be steep. Therefore, the slope of the upward gradient 122 is preferably calculated without the effect of the valley 151. For example, corresponding slopes of the upward gradients of the second donor concentration peak value 121 and the second hydrogen concentration peak value 141 can be calculated using the corresponding concentrations at the second depth Z2 and a depth Zc. The depth Zc may be located closer to the bottom 23 than the valley 151. The depth Zc in this example is located at the mean depth of the shallow area 150 in the depth direction.As another example, Zc can be a position where a hydrogen concentration distribution has a local minimum between the first hydrogen concentration peak value 131 and the second hydrogen concentration peak value 141. In this way, the slope of the upward gradient 122 of the second donor concentration peak value 121 can be normalized, excluding the effect of the valley 151. As described above, a slope of a concentration difference or a slope of a concentration ratio can be used for normalization. Fig. 11 shows an exemplary arrangement of corresponding elements on a top surface 21 of a semiconductor substrate 10. In Fig. 11, an outer edge of the semiconductor substrate 10 is designated as an outer edge 140. The semiconductor device 100 comprises an active section 120 and an edge termination section 90. The active section 120 is an area in which a main current flows between the top 21 and the bottom 23 of the semiconductor substrate 10 when the semiconductor device 100 is switched ON. In other words, the active section is an area in which current flows in the semiconductor substrate 10 in the depth direction from the top 21 to the bottom 23 or from the bottom 23 to the top 21 of the semiconductor substrate 10. In the active section 120 of this example, transistor sections 70 and diode sections 80 are provided. The transistor sections 70 and the diode sections 80 can be arranged side by side in the x-axis direction. In the example of Fig. 11, the transistor sections 70 and the diode sections 80 are arranged alternately in the x-axis direction. The transistor sections 70 can be provided at both ends of the active section 120 in the x-axis direction. The emitter electrode 52 can cover the transistor sections 70 and the diode sections 80. The active section 120 can designate an area covered by the emitter electrode 52. The transistor section 70 of this example comprises an IGBT (insulated-gate bipolar transistor), which is discussed in Figures 6 to 10. The diode section 80 of this example comprises an FWD (freewheeling diode). For each diode section 80, an N+-type cathode region 82 is provided in an area that contacts the bottom surface 23 of the semiconductor substrate 10. In Figure 11, the diode sections 80, indicated by solid lines, are areas in which the cathode regions 82 are provided on the bottom surface 23 of the semiconductor substrate 10. In the semiconductor device 100 of this example, collector regions 22 are provided in the areas that contact the bottom surface 23 of the semiconductor substrate 10, with the exception of the areas of the cathode regions 82. The diode sections 80 are surfaces onto which the cathode regions 82 are projected in the z-axis direction. The transistor sections 70 are surfaces in which the collector regions 22 are provided on the underside 23 of the semiconductor substrate 10 and a structural unit containing the emitter region 12 is provided at regular intervals on the top side 21 of the semiconductor substrate 10. A boundary between the diode section 80 and the transistor section 70 in the y-axis direction is a boundary between the cathode region 82 and the collector region 22. A section extending from the surface onto which the cathode region 82 is projected to one end of the active section 120, or a gate distributor 48 in the y-axis direction (a section indicated in Fig. 11 by dashed lines where the diode section 80 runs) may also be included in the diode section 80.Emitter area 12 is not included in the current section. The semiconductor device 100 of this example further comprises a gate metal layer 50 and a gate distributor 48. The semiconductor device 100 can also include corresponding contacts, such as a gate contact 116 and an emitter contact 118. The gate contact 116 is electrically connected to the gate metal layer 50 and the gate distributor 48. The emitter contact 118 is electrically connected to the emitter electrode 52. The gate metal layer 50 can be configured to enclose the active section 120 in a top view. The gate contact 116 and the emitter contact 118 can be located within the area enclosed by the gate metal layer 50. The gate metal layer 50 can be made of a metallic material such as aluminum or an aluminum-silicon alloy. The gate metal layer 50 is insulated from the semiconductor substrate 10 by the dielectric interlayer film 38. In Fig. 11, the dielectric interlayer film 38 is omitted. Furthermore, the gate metal layer 50 is provided separately from the emitter electrode 52. The gate metal layer 50 transmits a gate voltage, applied to the gate contact 116, to the transistor section 70. A conductive gate section 44 of the transistor section 70 is directly connected to the gate metal layer 50 or indirectly connected to the gate metal layer 50 via other conductive elements. The gate distributor 48 connects the gate metal layer 50 to the conductive gate section 44. The gate distributor 48 can be made of a semiconductor material such as polysilicon doped with impurities. A section of the gate distributor 48 can be positioned over the active section 120. The gate distributor 48 shown in Fig. 11 is configured to extend over the active section 120 in the x-axis direction. This prevents voltage dilution and latency, even within the active section 120, away from the gate metal layer 50. A section of the gate distributor 48 can be arranged to enclose the active section 120 along the gate metal layer 50. The gate distributor 48 can be connected to the conducting gate section 44 at one end of the active section 120. The edge termination section 90 is located between the active section 120 and the outer edge 140 of the semiconductor substrate 10 in the top surface 21 of the semiconductor substrate 10. In this example, the gate metal layer 50 is arranged between the edge termination section 90 and the active section 120. The edge termination section 90 can be arranged in a ring-like configuration such that it encloses the active section 120 in the top surface 21 of the semiconductor substrate 10. The edge termination section 90 in this example is arranged along the outer edge 140 of the semiconductor substrate 10. The edge termination section 90 reduces the concentration of the electric field on one side of the top surface 21 of the semiconductor substrate 10. The edge termination section 90 includes, for example, a guide ring, a field plate, a RESURF, and a combination thereof. Fig. 12 illustrates a cross-sectional view of an example along cc' from Fig. 11. Fig. 12 shows an exemplary arrangement in cross-section of the passage area 106, as described with reference to Figs. 1 to 10. In Fig. 12, the passage area 106 is hatched. It should be noted that the passage area 106 is shown only in the drift area 18 in Fig. 12 and is omitted in the buffer area 20, the collector area 22, and the cathode area 82. The cross-section shown in Fig. 12 is an XZ plane containing the edge-termination structure section 90, the transistor section 70, and the diode section 80. It should be noted that, although the gate metal layer 50 and the gate distributor 48 are located between the edge-termination structure section 90 and the transistor section 70, they are omitted in Fig. 12. The arrangement of the transistor sections 70 is similar to that of the IGBT described with reference to Figs. 6 to 10. The diode section 80 comprises the base region 14, the drift region 18, the cathode region 82, and the placeholder trench section 30 in the semiconductor substrate 10. The base region 14 and the drift region 18 are the same as the base region 14 and the drift region 18 in the transistor section 70. In the diode section 80, the base region 14 or a contact region 15 may be provided in areas in contact with the top surface 21 of the semiconductor substrate 10. The contact region 15 is a P+-type area with a higher doping concentration than the base region 14. The emitter region 12 is not provided in the diode section 80 of this example. Furthermore, the accumulation region 16 may or may not be provided in the diode section 80. The placeholder trench section 30 has the same arrangement as the gate trench section 40. However, the placeholder trench section 30 is electrically connected to the emitter electrode 52. The placeholder trench section 30 is configured such that it extends from the top surface 21 of the semiconductor substrate 10 through the base region 14 to the drift region 18. The placeholder trench section 30 can also be located within the transistor section 70. Within the transistor section 70, the placeholder trench section 30 and the gate trench section 40 can be arranged in a predetermined sequence. A central boundary region 190 may be present between the transistor section 70 and the diode section 80. The central boundary region 190 is an area in which no action is directly performed by either the transistor section 70 or the diode section 80. For example, an area of ​​the central boundary region 190 that is in contact with the top surface 21 may have the same arrangement as the diode section 80 on the top surface 21. Furthermore, in a top view, the collector area of ​​the central boundary region 190 may be provided in an area that is in contact with the bottom surface 23 by extending the collector area of ​​the transistor section 70. In Fig. 12, only an exemplary span of the central boundary region 190 is indicated by an arrow. In Fig. 12, this exemplary span, as the central boundary region 190, also has the same arrangement as the transistor section 70. In the drift region 18 of the diode section 80, a lifetime control region 192 can be provided closer to the top surface 21 than to the center in the depth direction. The lifetime control region 192 is an area in which a recombination center of a carrier (an electron or a hole) is provided at a higher concentration than in the surrounding area. The recombination center can be a vacancy-type defect such as a vacancy, a divacant, or the like, a transition, an interstitial atom, or a transition metal, etc. The lifetime control region 192 can extend from the diode section 80 to the central boundary region 190. Several guide rings 92, several field plates 94, and a channel closure 174 are provided in the edge termination structure section 90. The collector area 22 can be provided in a surface in contact with the bottom surface 23 of the edge termination structure section 90. Each guide ring 92 can be configured to enclose the active section 120 within the top surface 21. The multiple guide rings 92 can serve to direct the depletion layer generated in the active section 120 away from the semiconductor substrate 10. This can prevent a concentration of the electric field in the semiconductor substrate 10 and improve the breakdown voltage of the semiconductor device 100. The guide ring 92 of this example is a P+-type semiconductor region formed by ion implantation near the top surface 21. The depth of the bottom of the guide ring 92 can be greater than the depth of the bottom of the gate trench section 40 and the placeholder trench section 30. One upper surface of the guide ring 92 is covered with the dielectric interlayer film 38. The field plate 94 is made of a conductive material such as metal or polysilicon, etc. The field plate 94 can be made of the same material as the gate metal layer 50 or the emitter electrode 52. The field plate 94 is provided on the dielectric interlayer film 38. The field plate 94 is connected to the guide ring 92 by a through-hole provided in the dielectric interlayer film 38. A protective film 182 is provided on one side of the top surface 21 of the semiconductor substrate 10. The protective film 182 can cover the edge termination structure section 90, the gate metal layer 50, the boundary section 72, and a portion of the active section that is in contact with the boundary section 72. The protective film 182 can be an insulating film or an organic thin film. The protective film 182 in this example is polyimide. A plating layer 184 can be provided on the entire surface of an exposed section of the emitter electrode 52 where the protective film 182 is not formed. A surface of the plating layer 184 can be positioned closer to the top surface 21 than a surface of the protective film 182. The plating layer 184 is connected to an electrode terminal of a power module in which the semiconductor device 100 is mounted. The channel closure 174 is designed to be exposed on the top surface 21 and on a side surface at the outer edge 140. The channel closure 174 is an N-type surface with a higher doping concentration than in the drift region 18. The channel closure 174 serves to close the depletion layer that was created in the active section 120 at the outer edge 140 of the semiconductor substrate 10. Furthermore, the boundary section 72 can be provided between the transistor section 70 and the edge termination section 90. The boundary section 72 can include the contact area 15, the base area 14, and the placeholder trench section 30 in the top surface 21 of the semiconductor substrate 10. The boundary section 72 can include a P+-type well area 11 with a higher doping concentration than the base area 14. The well area 11 is in contact with the top surface 21 of the semiconductor substrate 10. The gate metal layer 50 and the gate distributor 48 can be provided above the well area 11. The depth of the bottom of the well area 11 can be the same as the depth of the bottom of the guide ring 92. A section of the trench in the boundary section 72 can be formed in the well area 11. In the boundary section 72, the collector area 22 can be provided in an area that is in contact with the underside 23. In this example, the second hydrogen concentration peak 141 is located between the bottom of the gate trench section 40 in the z-axis direction and the top surface 21 of the semiconductor substrate 10. While the second hydrogen concentration peak 141 is located deeper than the accumulation region 16 in the example of Fig. 12, it can be located at the same depth as the accumulation region 16, or at the same depth as the base region 14, or at the same depth as the emitter region 12. It should be noted that, as shown by the dashed lines in Fig. 12, the accumulation region 16 can also be formed within the diode section 80. The passage area 106 is formed in a span from the underside 23 of the semiconductor substrate 10 to the second hydrogen concentration peak value 141. In each figure, although the second hydrogen concentration peak value 141 and the passage area 106 do not overlap, the passage area 106 is formed such that it reaches the depth of the second hydrogen concentration peak value 141. Furthermore, the through-area 106 of this example is provided for each of the transistor section 70, the diode section 80, the boundary section 72, and the edge termination section 90. The depth of the through-area 106 can be the same in each of the transistor section 70, the diode section 80, the boundary section 72, and the edge termination section 90. In a top view, the through-area 106 can also be provided entirely within the semiconductor substrate 10. According to this example, the donor concentration can be matched substantially over the entire depth direction of the semiconductor substrate 10. In this example, an area where the pass-through region 106 is not formed is provided, in particular in a section in contact with the top surface 21 in the edge termination structure section 90. The donor concentration in the area where the pass-through region 106 is not formed is the same as the base doping concentration Db. The area where the pass-through region 106 is not formed is closer to the top surface 21 than the depth of the second hydrogen concentration peak value 141. In other words, the area where the pass-through region 106 is not formed can be an area whose doping concentration is essentially the base doping concentration Db. The area whose doping concentration is the base doping concentration Db is referred to as a base-doped region 180.In this example, the base-doped area 180 is in contact with the top surface 21 and is provided at a section that is flatter than the trough area 11. Fig. 13 shows a further example of an arrangement of a passage area 106. The passage area 106 in this example differs from the passage area 106 of Fig. 12 in its width in the depth direction. A top view of the arrangement is the same as that of the passage area 106 in Fig. 12. The second hydrogen concentration peak 141 of this example is located between the bottom of the gate trench section 40 and the bottom surface 23 of the semiconductor substrate 10. A thickness of the semiconductor substrate 10 in the depth direction is designated T1, and a distance between the second hydrogen concentration peak 141 and the bottom surface 23 of the semiconductor substrate 10 is designated T2. The distance T2 corresponds to a thickness of the passage area 106 in the depth direction. The distance T2 can be at least 40% and at most 60% of the thickness T1. In other words, the passage area 106 can be located from the bottom surface 23 of the semiconductor substrate 10 to approximately the midpoint in the depth direction of the semiconductor substrate 10. However, the distance T2 can be modified as appropriate. As described above, the base-doped region 180 is located closer to the top surface 21 than the second hydrogen concentration peak value 141. In this example, the base-doped region 180 extends from the bottom surface of the trench section to the second hydrogen concentration peak value 141 and has a depth of approximately T1-T2. In a top view, the base-doped region 180 of this example covers the entire surface of the semiconductor substrate 10. Fig. 14 shows a further example of an arrangement of a passage area 106. The passage area 106 in this example differs from the passage area 106 of Fig. 12 in its arrangement in a top view. The arrangement in the depth direction can be the same as that of the passage area 106 of Fig. 12. In this example, in a top view, the passage area 106 and the second hydrogen concentration peak value 141 are not provided in at least one section of the edge termination structure section 90. Fig. 14 shows an example in which the passage area 106 and the second hydrogen concentration peak value 141 are not provided for the entire edge termination structure section 90 in a top view. In other examples, the passage area 106 and the second hydrogen concentration peak value 141 may be provided at one end closer to the active section 120 of the edge termination structure section 90. In other words, the passage area 106 and the second hydrogen concentration peak value 141 are not provided in an area in contact with the outer edge 140 of the semiconductor substrate 10.In this example, since the second hydrogen concentration peak value 141 is not located near the outer edge 140, faults that form near the outer edge 140 can be suppressed. This can suppress an increase in leakage current at the outer edge 140. This means that the base-doped region 180 of this example is located in an area in contact with the outer edge 140 of the semiconductor substrate 10. In a top view, the base-doped region 180 of this example is located in at least one section of the edge termination section 90. Furthermore, in a top view, the base-doped region 180 can be located in the entire edge termination section 90 and in the boundary section 72. It should be noted that the arrangement of the through-area 106 in the boundary section 72 can be the same as in the edge termination structure section 90, can be the same as in the transistor section 70, or can be the same as in the diode section 80. Fig. 14 shows an example in which the through-area 106 is not provided in the boundary section 72. Fig. 15 shows further examples of an arrangement of a through-region 106. The arrangement in the depth direction of the through-region 106 of this example is the same as that of the through-region 106 shown in Fig. 13, and the arrangement in a top view of the through-region 106 of this example is the same as that of the through-region 106 shown in Fig. 14. That is, the through-region 106 is not provided in the edge termination structure section 90. Furthermore, the through-region 106 is provided in the transistor section 70 and the diode section 80, extending from the bottom surface 23 of the semiconductor substrate 10 to near the center of the semiconductor substrate 10 in the depth direction. The base-doped region 180 of this example is formed in the boundary section 72 and the edge termination section 90 from the top surface 21 to the buffer region 20. Furthermore, in the active section, the base-doped region 18 is formed in the drift region 18 closer to the top surface 21 than the second hydrogen concentration peak value 141. In a top view, the base-doped region 180 of this example is provided over the entire surface of the semiconductor substrate 10 on one side closer to the top surface 21 than the second hydrogen concentration peak value 141. Fig. 16A shows a further example of an arrangement of a through-section 106. This example differs from the examples in Figs. 12 to 15 in that the through-section 106 and the second hydrogen concentration peak value 141 are not provided in at least a portion of the diode section 80 in a top view. The further arrangements are the same as those of the examples described with reference to Figs. 12 to 15. Fig. 16A shows an example in which the through-area 106 and the second hydrogen concentration peak value 141 are not provided for the entire diode section 80 in a top view. In other words, the base-doped area 180 is provided for the entire diode section 80 in a top view. Furthermore, the base-doped area 180 is also fully provided for the boundary section 72 and the edge termination section 90. In other examples, the through-area 106 and the second hydrogen concentration peak value 141 may be provided at one end of the diode section 80 in contact with the transistor section 70. A different arrangement of the through-area 106 between the transistor section 70 and the diode section 80 can vary the doping concentration distribution in the diode section 80 and in the transistor section 70, as applicable. Fig. 16B shows an arrangement of a through-band 106 and a base-doped band 180, formed in an active section, which is the opposite of that shown in Fig. 16A. Forming the through-band 106 in the diode section 80 suppresses the expansion of a space charge region during reverse recovery and also suppresses waveform oscillation during reverse recovery. On the other hand, for example, designing the transistor section 70 as the base-doped band 180 enhances the expansion of a space charge region during a short circuit, thereby promoting hole injection and suppressing short-circuit disturbances. Fig. 17A shows further examples of an arrangement of a through-band 106. The arrangement in the depth direction of the through-band 106 in this example is the same as that of the through-band 106 shown in Fig. 13, and the arrangement in a top view of the through-band 106 in this example is the same as that of the through-band 106 shown in Fig. 16A. That is, the through-band 106 is not provided in the diode section 80. The through-band 106 is provided in the transistor section 70, extending from the underside 23 of the semiconductor substrate 10 to near the center of the semiconductor substrate 10 in the depth direction. Furthermore, in the example of Fig.17A the second hydrogen concentration peak value 141 is withdrawn closer to the bottom 23 from the bottom surface of the trench section and on one side closer to the top 21 than the second hydrogen concentration peak value 141, the basal-doped area 180 is formed over the entire surface in a top view. Fig. 17B shows a further example of an arrangement of a passage region 106. Fig. 17B is an arrangement of the passage region 106 and the base-doped region 180 opposite to that of Fig. 17A, which is formed in the active section. The example of Fig. 17B also achieves similar effects to those in Fig. 16B. To form the passage area 106, described with reference to Figures 14 to 17B, selective implantation of hydrogen ions is carried out in a second implantation step S1902, which will be discussed later, as shown in a top view. For example, hydrogen ions can be selectively implanted using the photoresist film 200 shown in Figures 14 to 17B. In this case, prior to the second implantation step S1902, the photoresist film 200, which has a predetermined thickness, is selectively formed in a section of the underside 23 of the semiconductor substrate 10. The thickness of the photoresist film 200 is sufficient to shield hydrogen ions. After the photoresist film 200 has formed, the second implantation step S1902 is performed. In an area where the photoresist film 200 has formed, it can shield hydrogen ions. Therefore, hydrogen ions do not penetrate the area covered by the photoresist film 200 in the semiconductor substrate 10. In areas where the photoresist film 200 has not formed, hydrogen ions are implanted to the second depth position Z2 depending on acceleration energies. It should be noted that in each example of Fig. 14, Fig. 15, Fig. 16A, Fig. 16B, Fig. 17A, and Fig. 17B, the photoresist film 200 is formed in contact with the underside 23 of the semiconductor substrate 10. In one step of the photoresist film 200 formation, the collector electrode 54 is not yet positioned on the underside 23. Fig. 17C is a diagram illustrating a minimum film thickness M of a photoresist film 200 to prevent hydrogen ions from penetrating a semiconductor substrate 10. Fig. 17C shows a film thickness M in relation to the span Rp of hydrogen ions. In this example, the hydrogen ions are implanted into the semiconductor substrate 10 by an accelerator via no absorbers other than the photoresist film 200. The range Rp of the hydrogen ions is uniquely determined by an acceleration energy in the accelerator. Furthermore, the minimum film thickness M of the photoresist film 200 that can shield the hydrogen ions is determined by the acceleration energy of the hydrogen ions. Accordingly, the minimum film thickness M of the photoresist film 200 can be represented by the span Rp of the hydrogen ions. Fig. 17C is a diagram showing an approximate straight line connecting three data points, each representing a relationship between the span Rp of the hydrogen ions and the film thickness M. The relationship between the film thickness M (µm) and the span Rp (µm) can be expressed as follows. The thickness of the photoresist film 200 is preferably equal to or greater than the minimum film thickness M expressed by the expression given above. Fig. 18A shows further examples of an arrangement of a through-area 106. In this example, a width T5 in the depth direction of the through-area 106 provided in the edge termination structure section 90 is smaller than a width T4 in the depth direction of the through-area 106 provided in the active section 120 (the diode section 80 in this example). In the diode section 80, the second hydrogen concentration peak value 141 can be located between the bottom of the placeholder trench section 30 and the top surface 21 of the semiconductor substrate 10. In the edge termination section 90, the second hydrogen concentration peak value 141 can be located between the guide ring 92 and the bottom surface 23 of the semiconductor substrate 10. The width T5 of the passage area 106 in the edge termination section 90 can be greater than half the thickness T of the semiconductor substrate 10. Furthermore, the width T3 in the depth direction of the through-area 106 provided in transistor section 70 can be smaller than the width T4 in the depth direction of the through-area 106 provided in diode section 80. In other words, the base-doped area 180 in transistor section 70 is formed deeper than the depth of the trench section. That is, the second hydrogen concentration peak 141 in transistor section 70 is positioned closer to the bottom surface 23 than the bottom surface of the trench section. In transistor section 70, the second hydrogen concentration peak 141 can be located between the bottom of the gate trench section 40 and the bottom surface 23 of the semiconductor substrate 10. The width T3 can be equal to, greater than, or less than the width T5. The width T3 of the through-area 106 in transistor section 70 can be greater than half the thickness T of the semiconductor substrate 10.This allows the base region 14, in which a channel is formed, to be spaced away from the second hydrogen concentration peak value 141 in the transistor section 70. In this way, an increase in errors near the channel can be suppressed. The through-band 106 in the boundary section 72 can have the same arrangement as the through-band 106 in the edge termination section 90, the same arrangement as the through-band 106 in the transistor section 70, or the same arrangement as the through-band 106 in the diode section 80. Furthermore, in the example of Fig. 18A, the through-band 106 need not be provided in the transistor section 70. The through-band 106 need not be provided in the diode section 80. The through-band 106 need not be provided in the edge termination section 90. The through-band 106 need not be provided in the boundary section 72. Fig. 18B is a further example of an arrangement of a through-area 106. In this example, a width T5 in the depth direction of the through-area 106 provided in the edge termination structure section 90 is smaller than a width T3 in the depth direction of the through-area 106 provided in the active section 120 (the transistor section 70 in this example). In transistor section 70, the second hydrogen concentration peak value 141 can be arranged between the bottom of the gate trench section 40 and the top 21 of the semiconductor substrate 10. The arrangement of the through-area 106 and the second hydrogen concentration peak value 141 in the edge termination structure section 90 is similar to the example shown in Fig. 18A. A width T4 in the depth direction of the through-area 106 provided in diode section 80 can be smaller than a width T3 in the depth direction of the through-area 106 provided in transistor section 70. In other words, the base-doped area 180 in diode section 80 is formed deeper than the depth of the trench section. That is, the second hydrogen concentration peak 141 in diode section 80 is positioned closer to the bottom 23 than the bottom surface of the trench section. In diode section 80, the second hydrogen concentration peak 141 can be located between the bottom of the placeholder trench section 30 and the bottom 23 of the semiconductor substrate 10. The width T4 can be equal to, greater than, or less than the width T5. The width T4 of the through-area 106 in diode section 80 can be greater than half the thickness T of the semiconductor substrate 10. The through-band 106 in the boundary section 72 can have the same arrangement as the through-band 106 in the edge termination section 90, the same arrangement as the through-band 106 in the transistor section 70, or the same arrangement as the through-band 106 in the diode section 80. Furthermore, in the example of Fig. 18B, the through-band 106 need not be provided in the transistor section 70. The through-band 106 need not be provided in the diode section 80. The through-band 106 need not be provided in the edge termination section 90. The through-band 106 need not be provided in the boundary section 72. As shown in Figures 12 to 18B, adjusting the arrangement of the passband 106 can easily adapt the donor concentration distribution in the transistor section 70, the diode section 80, and the edge termination section 90. The arrangement of the passband 106 is not limited to the examples shown in Figures 12 to 18B. Fig. 19 shows a flow diagram for forming a through-region 106 in a method for fabricating a semiconductor device 100. When the through-region 106 is formed, hydrogen ions are implanted to the first depth Z1 from the bottom surface 23 of the semiconductor substrate 10 in the first implantation step S1900. Furthermore, in the second implantation step S1902, the through-region 106 is formed by implanting hydrogen ions to the second depth Z2 from the bottom surface 23 of the semiconductor substrate 10. Either the first implantation step S1900 or the second implantation step S1902 can be performed first. It should be noted that if the first implantation step S1900 is performed first, and heat treatment is carried out between the first implantation step S1900 and the second implantation step S1902, in some cases the donor concentration in the through-region 106 could not be increased. In other words, in some cases, if heat treatment was performed before the formation of the through-region 106, hydrogen implanted in the first implantation step S1900 could not bond to the lattice defect in the through-region 106 and could leave the semiconductor substrate 10. Therefore, it is preferable not to perform heat treatment between the first implantation step S1900 and the second implantation step S1902. Heat treatment is a process of heating the semiconductor substrate 10 to, for example, 300 degrees Celsius or more. Following the first implantation step S1900 and the second implantation step 1902, a diffusion step S1904 is performed. In diffusion step S1904, the semiconductor substrate 10 is heat-treated to diffuse the hydrogen implanted to the first depth Z1 into the passage area 106. In diffusion step S1904, the semiconductor substrate 10 can be heated to 300 degrees Celsius or more. The heating temperature can be 350 degrees Celsius or more. In diffusion step S1904, the semiconductor substrate 10 can be heated for one hour or more, or for three hours or more. In diffusion step S1904, hydrogen is diffused to bind a crystal defect and hydrogen in the through-region 106, thus acting as a donor. In this way, the donor concentration in the through-region 106 can be increased. In diffusion step S1904, the minimum donor concentration in the through-region 106 is preferably higher than the donor concentration (the base doping concentration) of the semiconductor substrate 10 before the first and second implantation steps S1900 and S1902. In other words, the donor concentration is preferably higher than the base doping concentration across the entire through-region 106. To increase the donor concentration throughout the entire passage area 106, it is preferred to diffuse the hydrogen implanted at the first depth position Z1 to the vicinity of the second depth position Z2. In the first implantation step S1900, a sufficient amount of hydrogen can be diffused to the vicinity of the second depth position Z2 by adjusting the hydrogen dose implanted at the first depth position Z1. In the first implantation step S1900, it is preferred to determine a hydrogen dose such that a minimum donor concentration in the passage area 106 is higher than the base doping concentration. If several hydrogen donor peak values ​​24, as shown in Fig. 9 et seq., are formed in the buffer region 20, hydrogen ion implantation can be performed multiple times in addition to the hydrogen ion implantation in the first implantation step S1900 and the second implantation step S1902. Multiple hydrogen ion implantations to form the peak values ​​24 can be performed in the first implantation step S1900 or in the second implantation step S1902. In other words, the first implantation step S1900 can be performed multiple times, or the second implantation step S1902 can be performed multiple times. Furthermore, the first implantation step S1900 and the second implantation step S1902 can each be performed multiple times. If hydrogen ion implantation is performed several times in the second implantation step S1902, the photoresist film 200, which has a thickness that depends on the respective spans Rp of the hydrogen ions (see Fig. 14, etc.), can be formed. Alternatively, the photoresist film 200, which has a thickness sufficiently greater than a minimum film thickness M corresponding to the deepest span Rpmax (see Fig. 17C), can be formed in the repeated hydrogen ion implantations. Hydrogen ion implantation can be performed using the photoresist film 200, which has a film thickness M at an acceleration energy corresponding to each of the spans Rps. The thickness of the photoresist film 200 can be twice or more than the minimum film thickness M corresponding to the deepest span Rpmax.In this way, it can reduce the number of times the photoresist film 200 is formed, while ensuring the durability of the photoresist film 200 against repeated hydrogen ion implantations. Figures 20 to 26 are diagrams illustrating how to determine the hydrogen ion dose to be implanted at the first depth Z1 (referred to as the first dose). In the first implantation step S1900 of this example, a hydrogen dose greater than or equal to a minimum dose is implanted, determined by a diffusion coefficient of hydrogen in the semiconductor substrate 10 and a second depth position Z2 (i.e., a distance over which the hydrogen implanted at the first depth position Z1 diffuses). Fig. 20 shows an example of a carrier concentration distribution in a semiconductor substrate 10 after a diffusion step S1904. The carrier concentration distribution in Fig. 20 can be obtained, for example, by leakage resistance profiling. In each of Figs. 20 to 26, the underside 23 of the semiconductor substrate 10 is to be a reference position (0 µm) at a depth (µm). Furthermore, the first depth Z1 is at most 10 µm. Alternatively, the first depth Z1 can be treated as 0 µm. Figure 20 shows carrier concentrations of three types of semiconductor substrates 10. A first example 161 and a second example 162 are examples in which hydrogen ions are implanted to the first depth Z1 and the second depth Z2, respectively, and a third example 163 is an example in which hydrogen ions are implanted only to the second depth Z2. In each example, the hydrogen ion dose to the second depth Z2 (referred to as a second dose) was 1 × 10¹³ / cm². Furthermore, the hydrogen ion span to the second depth Z2 was 100 µm, and the acceleration energy was 3.1 MeV. The hydrogen ion span can be tuned by the acceleration energy or by an aluminum absorber, etc. In the first example 161 and in the second example 162, the acceleration energy of hydrogen ions to the first depth Z1 was 400 keV. In the first example 161, the first dose was 1 × 10¹⁵ / cm². In the second example 162, the first dose was 3 × 10¹⁴ / cm². After the hydrogen ions were implanted, the semiconductor substrates 10 of the respective examples were annealed for five hours at 370 degrees Celsius in the same annealing furnace. Fig. 20 shows carrier concentration distributions after annealing. In each example, lattice defects were formed in the through-region 106 (in the span from the bottom surface 23 of the semiconductor substrate 10 to the second depth position Z2) before annealing. Therefore, the carrier concentrations in the through-region 106 are reduced. After annealing, the carrier concentration increases due to donor formation, which is generated by the binding of hydrogen and lattice defects. However, in the third example 163, the carrier concentration hardly increases because hydrogen is not implanted to the first depth Z1. As shown in the first example 161 and the second example 162, the carrier concentrations in the transition regions 106 increase more as the first dose increases. It should be noted that in the second example 162, a valley of the carrier concentration is created at a position (near 80 µm depth) that is shallower than the second depth Z2. This can be understood because, if the hydrogen implanted at the first depth Z1 diffused in the depth direction, the concentration of the diffusing hydrogen was insufficient, and a sufficient concentration of hydrogen did not diffuse to a position deeper than x2. On the other hand, in the first example 161, the carrier concentration is higher than the base doping concentration (in this example 1.0 × 10¹⁴ / cm³) across the entire range of the passage area 10⁶ from depth 0 µm to the second depth Z2.This can be understood because, when the hydrogen implanted to the first depth Z1 diffused in the depth direction, the concentration of diffusing hydrogen was sufficient and a sufficient concentration of hydrogen diffused to a position deeper than x1. Assuming that the first dose is Q, the diffusion depth of hydrogen from the first depth is Z1 × (x1, x2) (cm), the diffusion coefficient of hydrogen is D (cm² / s), the diffusion time is t (s), and the basic doping concentration of the semiconductor substrate is 10 C0 (atoms / cm³), these relationships can be expressed by the following expression (1). Expression (1) is a value calculated from a solution of a diffusion equation. A solution where the diffusion equation is solved under a boundary condition where the total amount of hydrogen is constant is a normal distribution. In the solution of the obtained normal distribution, x is given by equation (1) when a concentration C(x, t) is equal to the basic doping concentration C0. The diffusion coefficient D of hydrogen in the semiconductor substrate 10 can be calculated numerically using equation (1). The diffusion depth x in the second example 162 can be determined according to a profile shape from Fig. 20. For example, the diffusion depth x can be a distance from the first depth position Z1 to the first inflection point in a valley of the carrier concentration. Alternatively, the diffusion depth x can be a distance from the first depth position Z1 to a position where the carrier concentration first falls below the base doping concentration. For the first example 161 in Fig. 20, Q = 1 × 10¹⁵ / cm², t = 5 h (= 1.8 × 10³ s), x₁ = 85 µm (= 8.5 × 10³ cm), and C₀ = 1 × 10¹⁴ / cm³. For the second example, Q = 3 × 1014 / cm2, t = 5h (= 1.8 × 103s), x2 = 75 µm (= 7.5 × 103cm) and C0 = 1 × 1014 / cm3. The lattice defects formed when hydrogen ions are implanted at the second depth Z2 are of various types, such as point defects, transition defects, and the like. Point defects include vacancy-type defects containing a vacancy and a divacant. In this case, the concentration of the lattice defect peaks at a position slightly closer to an ion implantation surface (the bottom surface 23 of the semiconductor substrate 10) at the second depth Z2. Because the hydrogen ions implanted at the first depth Z1 are bound to the lattice defects, the diffusion depth x1 of hydrogen in the first example 161 has a value (85 µm in this example) that is slightly smaller than the second depth Z2 (100 µm). Figure 21 shows a relationship between the diffusion coefficient D of hydrogen and a first dose Q. In Figure 21, the first example 161 and the second example 162, shown in Figure 20, are graphically represented. The dependence of the diffusion coefficient D on the first dose Q is not relatively strong. However, the diffusion coefficient D increases slightly more than the first dose Q. The hydrogen implanted at the first depth Z1 diffuses to the second depth Z2, while unsaturated binding sites in the passage area 106 are closed. It can be seen that the hydrogen diffuses readily, as the proportion of hydrogen diffusing into areas where unsaturated binding sites are closed increases with increasing first dose Q. It should be noted that the value of the diffusion coefficient D can vary depending on experimental conditions, etc.For the diffusion coefficient D shown in Fig. 21, a tolerance of at least ±50% is allowed. Furthermore, a tolerance of ±100% is allowed. Fig. 22 shows a relationship between a diffusion coefficient D and an annealing temperature T. Fig. 22 shows a diagram in which the diffusion coefficients described in Figs. 20 and 21 are obtained with respect to several annealing temperatures T and are graphically represented in an Arrhenius graph. In this example, the first dose Q = 1 × 10¹⁵ / cm². The diffusion coefficient D is expressed by D = D0 exp(-Ea / kBT). D0 is a constant, Ea is an activation energy, and kB is a Boltzmann constant. According to the diagram in Fig. 22, D0 = 0.33237 (cm² / s), Ea = 1.204 (eV). Accordingly, the diffusion coefficient of hydrogen in the semiconductor substrate 10 can be calculated. Fig. 23 shows a relationship between the diffusion depth of hydrogen and a first dose. In Fig. 23, the first example 161 and the second example 162, shown in Fig. 20, are graphically represented by black spheres. As described with reference to Fig. 20, for the first example 161, the first dose Q = 1 × 10¹⁵ / cm² and the diffusion depth x₁ = 85 µm. Furthermore, for the second example 162, the first dose Q = 3 × 10¹⁴ / cm² and the diffusion depth x₂ = 75 µm. As shown in Fig. 23, connecting the graphical representation of the first example 161 and the graphical representation of the second example 162 with a straight line can determine a first dose for corresponding diffusion depths x. In other words, the straight line indicates a minimum first dose for corresponding diffusion depths x. In the first implantation step S1900, setting a first dose greater than this straight line allows the total donor concentration in the passage area 106 to be higher than the base doping concentration. As an example, a first dose Q (ions / cm²) can satisfy the following equation if the second depth Z2 is a diffusion depth x (µm). It should be noted that in this example, the unit for x is (µm). As described above, when hydrogen ions are implanted to the second depth Z2, a peak value of a crystal defect concentration is provided at a position slightly shallower than the second depth Z2. The horizontal axis in Fig. 23 corresponds to peak value positions of a crystal defect concentration. Therefore, when the passage region 106, which has a length X0 corresponding to the horizontal axis of Fig. 23, is formed, hydrogen ions are implanted to the second depth Z2 according to a span Rp in the following equation, taking into account a scatter ΔRp during ion implantation.The passage area 106 can be formed substantially entirely in the depth direction of the semiconductor substrate 10 by setting a peak value position of a crystal defect concentration (a position of length X0 from the bottom 23) closer to the top 21 than to the bottom of the trench section provided on the top 21 of the semiconductor substrate 10. A minimum dose can be calculated on the basis of the following equation (2), which is a variant of equation (1). The diffusion coefficient D is calculated according to the procedure described in Fig. 22. In Fig. 23, the minimum doses calculated from equation (2) are graphically represented by white spheres. It should be noted that, because the diffusion coefficient D has a quadratic distance extent, it can be expressed as a function of the diffusion depth x of hydrogen. Fig. 24 shows a relationship between a diffusion coefficient D and a diffusion depth x. In Fig. 24, the first example 161 and the second example 162, which are shown in Fig. 20, are graphically represented. As shown in Fig. 24, the diffusion coefficient D increases as the diffusion depth x increases. As the diffusion depth x increases, the distance from the first depth Z1 to a peak value of a crystal defect concentration also increases. Therefore, the proportion of areas with relatively few lattice defects increases in the transition region 106. Since fewer lattice defects occur as the diffusion coefficient increases with increasing diffusion depth x, the average diffusion coefficient is higher in the transition region 106. It should be noted that the second dose in Figures 20 to 24 is 1 × 10¹³ / cm². However, if the second dose is changed, a minimum dose of the first dose can be determined in a similar manner. Furthermore, a donor concentration in the passage area 10⁶ can be adjusted by tuning the second dose. A concentration of lattice defects formed in the passage area 10⁶ can also be adjusted by tuning the second dose. Additionally, although the annealing temperature is set to 370 degrees Celsius, a minimum dose can be determined according to equation (2) if the annealing temperature is changed. Fig. 25 shows straight lines that define a minimum dose for each annealing temperature. In this example, the diffusion coefficient D is constant regardless of the diffusion depth. In the first implantation step S1900, a hydrogen ion dose higher than the minimum doses indicated by the corresponding straight lines in Fig. 25 can be implanted to the first depth Z1. Fig. 26 shows a relationship between a second dose and a minimum dose of a first dose. In this example, the relationship is given for each diffusion depth x. In the first implantation step S1900, a hydrogen ion dose higher than the minimum doses indicated by the corresponding curves in Fig. 26 can be implanted to the first depth Z1. Fig. 27 is a diagram illustrating an example of a first depth Z1. Fig. 27 shows a donor concentration distribution and a chemical hydrogen concentration distribution in the depth direction of a semiconductor substrate 10. For the chemical hydrogen concentration distribution, only the distribution near the peak values ​​is shown schematically. In Fig. 27, the distributions near the top surface 21 of the semiconductor substrate 10 (an area 100 µm or more from the bottom surface 23) are omitted. Furthermore, a carrier concentration distribution in an N-type region of the semiconductor substrate 10 can be used as the donor concentration distribution. In this example, the first depth Z1 of the first hydrogen concentration peak value 131 is contained within a span of 5 µm or less from the bottom surface 23 of the semiconductor substrate 10 in the depth direction. In the semiconductor device 100, arrangements other than the first depth Z1 are the same as any aspects described with respect to Figs. 1 to 26. The donor concentration distribution of the semiconductor device 100 of this example is similar to that of the example of Fig. 10. Positioning the first depth Z1 near the base 23 can increase the distance between the first depth Z1 and the second depth Z2. Therefore, the donor concentration can be precisely controlled over a larger area within the semiconductor substrate 10. The first depth Z1 can be located within a range of 4 µm or less from the base 23, or within a range of 3 µm or less from the base 23. To diffuse hydrogen over a larger span, it is preferred to increase the hydrogen dose implanted at the first depth Z1. In this example, the hydrogen dose to be implanted at the first depth Z1 can be at least 1 × 10¹⁵ atoms / cm², at least 1 × 10¹⁶ atoms / cm², at least 1 × 10¹⁷ atoms / cm², or at least 1 × 10¹⁸ atoms / cm². At the first depth Z1, the first donor concentration peak 111 can be formed by a hydrogen donor. The donor concentration of the first donor concentration peak 111 can be at least 1 × 10¹⁵ / cm³ or at least 1 × 10¹⁶ / cm³. The donor concentration of the first donor concentration peak 111 can be at most 1 × 10¹⁷ / cm³. Hydrogen implantation to the first depth Z1 can be achieved by plasma doping. In plasma doping, a plasma excitation gas and a raw material gas containing hydrogen are supplied to a container holding the semiconductor substrate 10. The plasma excitation gas can contain inert elements such as argon. Monophosphine (PH3), for example, can be used as the raw material gas. By generating plasma using these gases in the container and then exposing the bottom surface 23 of the semiconductor substrate 10 to the plasma, a high concentration of hydrogen can be easily implanted to a shallow position from the bottom surface 23. Furthermore, implanting the hydrogen to the shallow position near the bottom surface 23 using plasma doping can suppress lattice defects that would otherwise be generated in the semiconductor substrate 10.Furthermore, the annealing temperature can be reduced to such an extent due to fewer lattice defects that the throughput for manufacturing the semiconductor device 100 can be improved. However, one method of implanting hydrogen to the first depth Z1 is not limited to plasma doping. Hydrogen implantation to the second depth Z2 of the second hydrogen concentration peak value 141 can be performed by means other than plasma doping. Hydrogen can be implanted to the second depth Z2 by accelerating the hydrogen ions using an electric field, and so on. The second depth position Z2 can be 80 µm or more from the bottom surface 23 in the depth direction. The second depth position Z2 can be 90 µm or more, or 100 µm or more from the bottom surface 23. The distance between the first depth position and the second depth position in the depth direction can be 50% or more, 65% or more, or 80% or more of the thickness of the semiconductor substrate 10 in the depth direction. Fig. 28 shows another example of a donor concentration distribution and a chemical hydrogen concentration distribution in the depth direction of a semiconductor substrate 10. The first depth Z1 of this example is the same as in the example of Fig. 27. In addition, the second depth Z2 can be located closer to the top surface 21 of the semiconductor substrate 10. “Closer to the top surface 21” refers to an area extending from the center in the depth direction to the top surface 21 of the semiconductor substrate 10. In each example from Fig. 27 or Fig. 28, the chemical hydrogen concentration distribution can have one or more hydrogen concentration peaks 194 between the first depth Z1 and the second depth Z2. The hydrogen concentration peaks 194 can be located in the buffer region 20, as described in Fig. 6, etc. The first hydrogen concentration peak 131 can be located in the buffer region 20 or between the buffer region 20 and the bottom 23. Fig. 29 shows an example of a chemical hydrogen concentration distribution and a chemical argon concentration distribution near a first hydrogen concentration peak value 131. In this example, the first hydrogen concentration peak value 131 is a peak value corresponding to the hydrogen implanted by plasma doping, and the hydrogen concentration peak value 194 is a peak value corresponding to the hydrogen implanted by other means, instead of plasma doping. In some cases, when hydrogen is implanted to the first depth position Z1 via plasma doping, impurities other than hydrogen can be implanted in the vicinity of the first depth position Z1. For example, in some cases, when argon gas is used for plasma excitation, argon can be implanted in the vicinity of the first depth position Z1. Figure 29 shows a peak argon concentration value of 196 at a depth position Z0. Depth position Z0 can be located between the bottom position 23 and the first depth position Z1. Because argon is a heavier element than hydrogen, the argon concentration peak value 196 tends to form at a position that is shallower than the first hydrogen concentration peak value 131. In this example, a peak chemical argon concentration is not provided between the first depth position Z1 and the second depth position Z2. Because the hydrogen concentration peak 194 at the second depth position Z2 is formed in a manner other than plasma doping, no argon is implanted into the vicinity of the hydrogen concentration peak 194. The chemical argon concentration between the first depth position Z1 and the second depth position Z2 is lower than the argon concentration peak 196. A maximum value of the chemical argon concentration between the first depth position Z1 and the second depth position Z2 can be less than or equal to a minimum value of the chemical argon concentration between the bottom surface 23 and the first depth position Z1. Depending on the composition of the gas used for plasma doping, other impurities besides argon can be implanted into the semiconductor substrate 10. If PH2 gas is used for plasma doping, a phosphorus concentration peak value can be provided between the bottom layer 23 and the first depth position Z1. If BF3 gas is used for plasma doping, a fluorine concentration peak value can be provided between the bottom layer 23 and the first depth position Z1, or a boron concentration peak value can be provided between the bottom layer 23 and the first depth position Z1. The concentration value of a peak value of argon, phosphorus, fluorine, or boron can be lower than the concentration value of the first hydrogen concentration peak value 131.A concentration value of the peak concentration value of argon, phosphorus, fluorine or boron may be less than or equal to half a concentration value of the first hydrogen concentration peak value 131 or may be less than or equal to one tenth of a concentration value of the first hydrogen concentration peak value 131. Fig. 30 is a diagram illustrating further arrangement examples of a semiconductor device 100. The semiconductor device 100 of this example comprises the transistor section 70 and the diode section 80 as in the example shown in Fig. 11. The arrangement of the transistor section 70 is the same as that of the example shown in Fig. 6. The transistor section 70 and the diode section 80 are arranged side by side in the x-axis direction. The diode section 80 of this example differs from a configuration of the transistor section 70 in that the diode section 80 includes the placeholder trench sections 30 instead of the gate trench sections 40, the cathode region 82 instead of the collector region 22, and does not include the emitter regions 12. The further arrangement is similar to that of the transistor section 70. The placeholder trench section 30 can have the same arrangement as the gate trench section 40. The placeholder trench section 30 comprises a dielectric placeholder film 32 and a conductive placeholder section 34. The dielectric placeholder film 32 and the conductive placeholder section 34 can have the same arrangement and material as the dielectric gate film 42 and the conductive gate section 44. However, it should be noted that the conductive gate section 44 is electrically connected to the gate electrode, while the conductive placeholder section 34 is electrically connected to the emitter electrode 52. It should also be noted that the placeholder trench section 30 can be provided within the transistor section 70. That is, a portion of the gate trench section 40 within the transistor section 70 can be replaced by the placeholder trench section 30. The cathode region 82 is exposed on the underside 23 of the semiconductor substrate 10, as in the case of the collector region 22. The cathode region 82 is connected to the collector electrode 54 in the underside 23. The cathode region 82 is an N+-type region in which an N-type impurity, such as phosphorus, is doped. The buffer region 20 can be provided between the cathode region 82 and the drift region 18. Furthermore, the base region 14 on the top surface 21 in the diode section 80 can be exposed. The base region 14 in the diode section 80 is electrically connected to the emitter electrode 52. According to such a configuration, the diode section 80 acts as a diode. In this example, hydrogen is also implanted at the first depth position Z1 and the second depth position Z2 in the diode section 80. Furthermore, the pass region, which is similar to that in the transistor section 70, is also formed in the diode section 80. Any concentration distribution in the transistor section 70 can be the same as any aspect described with reference to Figures 1 to 29. A chemical hydrogen concentration distribution in the depth direction of the diode section 80 can be the same as the chemical hydrogen concentration distribution in the depth direction of the transistor section 70. Fig. 31 shows an example of a carrier concentration distribution, a chemical hydrogen concentration distribution, and a chemical boron concentration distribution along line DD from Fig. 30. Line DD passes through the collector region 22 and part of the buffer region 20 in transistor section 70. The collector region 22 of this example is formed by the implantation of boron. The boron in this example is implanted in the collector region 22 in a separate step from the hydrogen of the first hydrogen concentration peak value 131. At least one section of the boron in the collector region 22 can also be implanted by plasma doping to implant the hydrogen of the first hydrogen concentration peak value 131. The first hydrogen concentration peak 131 is located in the buffer region 20 in the example of Fig. 7, etc. In this example, the first hydrogen concentration peak 131 is located in the cathode region 82 and the collector region 22. Because the doping concentration in the cathode region 82 and the collector region 22 is very high, changes in the carrier concentration distribution can be suppressed, even if a high concentration of hydrogen donors is generated by providing the first hydrogen concentration peak 131 in the cathode region 82 and the collector region 22. This allows for easier suppression of effects on the properties of the semiconductor device 100. The concentration of the first hydrogen concentration peak value 131 is set such that the hydrogen donor concentration is considerably lower than the carrier concentration at the first depth position Z1. The activation ratio of hydrogen is approximately 1%. 1% of the chemical hydrogen concentration can be lower than the chemical boron concentration at the first depth position Z1. Furthermore, a peak value of the carrier concentration distribution in collector area 22 is located closer to a peak value of the chemical boron concentration than the first hydrogen concentration peak value 131. In the example of Fig. 31, the peak value of the chemical boron concentration is located at the bottom 23. The peak value of the carrier concentration distribution in collector area 22 can be the same as the peak value of the chemical boron concentration. The first hydrogen concentration peak value 131 can be located between the peak value of the carrier concentration distribution in collector area 22 and the buffer area 20. In this example, the peak value of the carrier concentration distribution in collector area 22 coincides with the bottom 23.It should be noted that in buffer area 20 the depth position of one or more hydrogen concentration peak values ​​194 and the depth position of one or more peak values ​​24 of the carrier concentration distribution may coincide. Fig. 32 shows an example of a carrier concentration distribution, a chemical hydrogen concentration distribution, and a chemical phosphorus concentration distribution along line EE from Fig. 30. Line EE passes through the cathode region 82 and part of the buffer region 20 in the diode section 80. The cathode region 82 of this example is formed by implanting phosphorus. The phosphorus in the cathode region 82 is implanted in a step separate from the hydrogen of the first hydrogen concentration peak 131. At least a portion of the phosphorus in the cathode region 82 can be implanted by plasma doping to implant the hydrogen of the first hydrogen concentration peak 131. The first hydrogen concentration peak value 131 of this example is located in the cathode region 82 and the collector region 22. The concentration of the first hydrogen concentration peak value 131 is set such that the hydrogen donor concentration is considerably lower than the carrier concentration at the first depth Z1. The activation ratio of hydrogen is approximately 1%. 1% of the chemical hydrogen concentration can be lower than the chemical phosphorus concentration at the first depth Z1. Furthermore, a peak value of the carrier concentration distribution in the cathode region 82 is located closer to a peak value of the chemical phosphorus concentration than the first hydrogen concentration peak value 131. In the example of Fig. 32, the peak value of the chemical phosphorus concentration is located on the bottom surface 23. The peak value of the carrier concentration distribution in the cathode region 82 can be the same as the peak value of the chemical phosphorus concentration. The first hydrogen concentration peak value 131 can be located between the peak value of the carrier concentration distribution in the cathode region 82 and in the buffer region 20. In this example, the peak value of the carrier concentration distribution in the cathode region 82 coincides with the bottom surface 23.It should be noted that in buffer area 20 the depth position of one or more hydrogen concentration peak values ​​194 and the depth position of one or more peak values ​​24 of the carrier concentration distribution may coincide. Fig. 33 is a flowchart illustrating part of a process for manufacturing a semiconductor device 100. Prior to the steps shown in Fig. 33, structures such as the corresponding trench sections, the emitter regions 12, the base regions 14, and the accumulation region 16 can be formed on one side of the top surface 21. In this example, in implantation step S3300, hydrogen ions are implanted to the second depth Z2 from the underside 23 of the semiconductor substrate 10. Implantation step S3300 can be the same as the second implantation step S1902 in the example shown in Fig. 19. Additionally, in implantation step S3302, hydrogen ions are implanted to the first depth Z1 from the underside 23 of the semiconductor substrate 10. In implantation step S3302, hydrogen ions are implanted by plasma doping. The hydrogen dose in implantation step S3302 can be the same as the hydrogen dose in the first implantation step S1900 in the example shown in Fig. 19. Either implantation step S3300 or implantation step S3302 can be performed first. Following implantation steps S3300 and S3302, a diffusion step S3304 is performed. Diffusion step S3304 is similar to diffusion step S1904 in the example shown in Fig. 19. In diffusion step S3304, hydrogen is diffused to bond a lattice defect with hydrogen in the passage region 106, thus acting as a donor. In this way, the donor concentration in the passage region 106 can be increased. Following diffusion step S3304, a grinding step S3306 is performed. In grinding step S3306, one side of the bottom surface 23 of the semiconductor substrate 10 is ground by chemical-mechanical polishing (CMP), etc. Grinding step S3306 can be performed on a surface shallower than the first depth Z1 or on a surface deeper than the first depth Z1. This can grind areas where a high concentration of hydrogen is distributed, thereby reducing the amount of hydrogen near the bottom surface 23. Following the grinding step S3306, structures such as the collector region 22, the cathode region 82, and the buffer region 20 are formed on one side of the bottom surface 23 in a single-side structure formation step S3308. In this step, laser annealing can be performed in the vicinity of the bottom surface 23 after the implantation of dopants into the cathode region 82 and the buffer region 20. This allows for localized, high-temperature heat treatment of the area surrounding the bottom surface 23 of the semiconductor substrate 10. Furthermore, after laser annealing, dopants such as hydrogen can be implanted into the buffer region 20. Following the implantation of the dopants into the buffer region 20, the entire semiconductor substrate 10 can be heat-treated in an annealing furnace. Fig. 34 is a flowchart illustrating part of a method for manufacturing a semiconductor device 100. The method for manufacturing this example differs in that it includes a laser annealing step S3307 instead of the grinding step S3306 of Fig. 33. The remaining steps are the same as those of the example in Fig. 33. In laser annealing step S3307, the underside 23 of the semiconductor substrate 10 is laser annealed. In laser annealing step S3307, a laser can be directed near the first depth Z1. This can remove at least some of the hydrogen near the first depth Z1 from the semiconductor substrate 10. This can reduce the chemical hydrogen concentration near the first depth Z1. In laser annealing step S3307, a laser can be directed in such a way that the first hydrogen concentration peak value 131 remains, or a laser can be directed in such a way that the first hydrogen concentration peak value 131 does not remain. It should be noted that heavier elements such as argon tend to remain in the semiconductor substrate 10 compared to hydrogen, even when a laser is directed. Therefore, in some cases, even when laser annealing step S3307 is performed, a concentration peak value of an impurity such as argon may not remain.Argon, shown in Fig. 29, is present in the semiconductor substrate 10. Furthermore, in laser annealing step S3307, a laser can be emitted to transistor section 70 and does not have to be emitted to diode section 80. If a high concentration of hydrogen donors remains on the underside 23 of diode section 80, its influence on properties is relatively small. In this case, the chemical hydrogen concentration at the first depth Z1 in diode section 80 is higher than the chemical hydrogen concentration at the first depth Z1 in transistor section 70. In the examples shown in Fig. 19, Fig. 33 and Fig. 34, hydrogen ion implantation to the first depth Z1 and to the second depth Z2 and heat treatment can be carried out before, after or during the formation of the structures on one side of the underside. Fig. 35 shows an example sequence of hydrogen ion implantation to a first depth Z1 and a second depth Z2 in a single step of structure formation on one side of a bottom surface. In this example, the hydrogen ion implantation to the first depth Z1 and the second depth Z2 and the heat treatment are performed in a single step of buffer region formation S3504 to form buffer region 20. The step of forming structures on one side of a bottom surface can be performed after a step of forming structures on one side of a top surface (S3500), such as the trench section. The step of forming structures on one side of a bottom surface comprises a step of forming a collector region (S3502) and a step of forming a buffer region (S3504). In Fig. 35, the subsequent steps in the step of forming structures on one side of a bottom surface are omitted. In this example, in the step of forming a buffer region (S3504), hydrogen ions are implanted at several positions, including the first depth Z1 and the second depth Z2. In S3504, the semiconductor substrate 10 is heat-treated to allow the hydrogen ions to diffuse after implantation.After the step of forming structures on one side of a bottom surface, a step of forming a collector electrode S3506 can be performed. Fig. 36 shows another example of the implantation of hydrogen ions to a first depth Z1 and a second depth Z2 in the step of forming structures on one side of a bottom surface. In this example, the hydrogen ion implantation to the first depth Z1 and the heat treatment are performed in a single step of forming a cathode region S3503. Furthermore, the hydrogen ion implantation to the second depth Z2 and the heat treatment are performed in the step of forming a buffer region S3506. The step of forming structures on one side of a bottom surface can be performed after the step of forming structures on one side of a top surface (S3500), such as the trench section. The step of forming structures on one side of a bottom surface in this example includes the step of forming a cathode region (S3503) and the step of forming a buffer region (S3504). In Fig. 36, the further steps in the step of forming structures on one side of a bottom surface are omitted. The semiconductor device 100 of this example can comprise the transistor section 70 and the diode section 80. In this case, after forming the cathode region 82, 23 collector regions 22 of the P-type can be formed in sections of the cathode regions 82 by selectively implanting P-type dopants. In the step of forming a cathode region S3503, raw material gas such as PH3, containing N-type dopants such as phosphorus, can be used. In the step of forming a cathode region S3503, hydrogen ions are implanted into the entire bottom surface 23 to the first depth Z1. Furthermore, after the optional formation of the collector region 22 on the underside 23, the cathode regions 82 can be formed by implanting N-type dopants and hydrogen ions into the entire underside 23. In this case, to prevent a conductivity type from being reversed to an N-type, a high concentration of P-type dopants can be pre-implanted in the collector region 22. According to this procedure, the first depth Z1 is located in the collector region 22 and in the cathode region 82. It should be noted that if the semiconductor device 100 comprises not the transistor section 70 but the diode section 80, the step of forming the collector region 22 can be omitted. Furthermore, hydrogen implantation to the second depth Z2 can be performed in the step of forming the buffer region 20. After the step of forming structures on one side of a bottom surface, a step of forming a collector electrode S3506 can be performed. It should be noted that the operations, procedures, steps, and stages of each process performed by a device, system, program, or method shown in the claims, embodiments, or drawings may be carried out in any order, as long as the order is not specified by "before," "before," or the like, and as long as the output of a preceding process is not used in a subsequent process. Even if process sequences are conveniently described in the claims, embodiments, or drawings using phrases such as "first" or "then," this does not necessarily mean that they must be performed in that order. REFERENCE MARK LIST 10 Semiconductor substrate 11 Well area 12 Emitter area 14 Base area 15 Contact area 16 Accumulation area 18 Drift area 20 Buffer area 21 Top side 22 Collector area 23 Bottom side 24, 25 Peak values ​​30 Placeholder trench section 32 Dielectric placeholder film 34 Conductive placeholder section 38 Dielectric intermediate film 40 Gate trench section 42 Dielectric gate film 44 Conductive gate section 48 Gate distributor 50 Gate metal layer 52 Emitter electrode 54 Collector electrode 70 Transistor section 72 Limiting section 80 Diode section 82 Cathode area 90 Edge termination section 92 Guard ring 94 Field plate 100 Semiconductor device 106 Pass-through area 111 First donor concentration peak value 112, 122, 132, 142, 172 Upward slope 113, 123, 133, 143, 173 Downward slope 114, 124, 125, 134, 144,145 Inclination 116 Gate contact 118 Emitter contact 120 Active section 121 Second donor concentration peak value 131 First hydrogen concentration peak value 140 Outer edge 141 Second hydrogen concentration peak value 150 Flat area 151 Valley 161 First example 162 Second example 163 Third example 171 Vacancy concentration peak value 174 Channel closure 175 Vacancy defect concentration distribution 180 Base-doped area 181 Undoped area 182 Protective film 184 Plating layer 190 Mid-range boundary 192 Lifetime control area 194 Hydrogen concentration peak value 196 Argon concentration peak value 200 Photoresist film

Claims

A semiconductor device (100) comprising a semiconductor substrate (10) having a top surface (21) and a bottom surface (23), the semiconductor device (100) further comprising: a drift region (18) of a first conductivity type provided on the semiconductor substrate (10); a base region (14) of a second conductivity type provided between the drift region (18) and the top surface (21); a high concentration region of the first conductivity type or the second conductivity type provided in contact with the bottom surface (23) in the semiconductor substrate (10); and a buffer region (20) of the first conductivity type provided between the high concentration region and the drift region (18), the buffer region (20) having one or more donor concentration peaks whose donor concentration is higher than that of the drift region (18), wherein: a donor concentration of the drift region (18) over the entire drift region (18) in the depth direction connecting the top side (21) and the bottom side (23) is higher than a base doping concentration of the semiconductor substrate.The semiconductor device (100) according to claim 1, wherein in the depth direction, a hydrogen concentration distribution includes a first hydrogen concentration peak (131) and a second hydrogen concentration peak (141), and a donor concentration distribution includes a first donor concentration peak (111) and a second donor concentration peak (121), and the first hydrogen concentration peak (131) and the first donor concentration peak (111) are placed at a first depth, and the second hydrogen concentration peak (141) and the second donor concentration peak (121) are placed at a second depth deeper than the first depth relative to the bottom surface (23).The semiconductor device (100) according to claim 2, wherein the donor concentration distribution between the first depth and the second depth comprises a flat region (150) in which a value of a donor concentration distribution is within ±50% of an average concentration of a donor concentration distribution in a first region, assuming that a length from the first depth to the second depth is ZL, the first region is a region of a length of 0.5 ZL between two points each spaced by 0.25 ZL from a center between the first depth and the second depth in the depth direction to either the first depth or the second depth, and a length of the flat region (150) in the depth direction is 10% or more of a thickness of the semiconductor substrate in the depth direction.The semiconductor device (100) according to claim 2, wherein the donor concentration distribution between the first depth and the second depth comprises a flat region in which a value of a donor concentration distribution is within ±50% of an average concentration of a donor concentration distribution in a first region, assuming that a length from the first depth to the second depth is ZL, the first region is a region of a length of 0.5 ZL between two points each spaced by 0.25 ZL from a center between the first depth and the second depth in the depth direction to either the first depth or the second depth, and a length of the flat region (150) in the depth direction is 10 μm or more.The semiconductor device (100) according to claim 1, wherein the drift region (18) includes a flat region in which regions in which a difference between a maximum value and a minimum value of a donor concentration is 50% or less of the maximum value of the donor concentration are consecutive in the depth direction, and a length of the flat region in the depth direction is 10 μm or more.The semiconductor device (100) according to claim 1, wherein the drift region (18) includes a flat region in which regions in which a difference between a maximum value and a minimum value of a donor concentration is 50% or less of the maximum value of the donor concentration are consecutive in the depth direction, and a length of the flat region in the depth direction is 10% or more of a thickness of the semiconductor substrate (10) in the depth direction.The semiconductor device (100) according to claim 5 or 6, wherein a hydrogen concentration distribution has a first hydrogen concentration peak and a second hydrogen concentration peak, and a donor concentration distribution has a first donor concentration peak and a second donor concentration peak in a depth direction, wherein the first hydrogen concentration peak and the first donor concentration peak are placed at a first depth, and the second hydrogen concentration peak and the second donor concentration peak are placed at a second depth deeper than the first depth relative to the bottom surface (23).The semiconductor device (100) according to any one of claims 1 to 7, wherein the drift region (18) comprises hydrogen as a donor.The semiconductor device (100) according to any one of claims 2 to 4 and 7, wherein each concentration peak includes an upward slope at which a concentration value increases from the lower side (23) toward the upper side (21), and a value at which a gradient of the upward slope of the second donor concentration peak (121) is standardized by a gradient of the upward slope of the second hydrogen concentration peak (141) is smaller than a value at which a gradient of the upward slope of the first donor concentration peak (111) is standardized by a gradient of the upward slope of the first hydrogen concentration peak (131).The semiconductor device (100) according to claim 9, wherein each hydrogen concentration peak (131, 141) comprises a downward slope at which a concentration value decreases from the lower side (23) toward the upper side (21), wherein at the second hydrogen concentration peak (141), a gradient of the upward slope is smaller than a gradient of the downward slope.The semiconductor device (100) according to claim 10, wherein each donor concentration peak (111, 121) comprises a downward slope at which a concentration value decreases from the bottom surface (23) toward the top surface (21), wherein at the second donor concentration peak (121), a gradient of the upward slope is smaller than a gradient of the downward slope.The semiconductor device (100) according to any one of claims 9 to 11, wherein a concentration value of the second hydrogen concentration peak (141) is smaller than a concentration value of the first hydrogen concentration peak (131).The semiconductor device (100) according to any one of claims 9 to 12, wherein the first donor concentration peak (111) is the donor concentration peak in the buffer region (20).The semiconductor device (100) according to any one of claims 9 to 13, further comprising an accumulation region (16) provided between the base region (14) and the drift region (18), the accumulation region (16) having one or more donor concentration peaks whose donor concentration is higher than that of the drift region (18), the second donor concentration peak (121) being the donor concentration peak in the accumulation region (16).The semiconductor device (100) according to claim 14, wherein the accumulation region (16) has the donor concentration peak of a donor other than hydrogen in addition to the second donor concentration peak (121).The semiconductor device (100) according to any one of claims 9 to 13, further comprising an accumulation region (16) provided between the base region (14) and the drift region (18), the accumulation region (16) having one or more donor concentration peaks whose donor concentration is higher than that of the drift region (18), the second donor concentration peak (121) being placed between the buffer region (20) and the accumulation region (16).The semiconductor device (100) according to any one of claims 9 to 15, further comprising a gate trench portion (40) provided on the top surface (21) of the semiconductor substrate, wherein the second donor concentration peak is placed between a bottom of the gate trench portion (40) and the top surface (21) of the semiconductor substrate.The semiconductor device (100) according to any one of claims 9 to 17, further comprising: an active portion (120) provided in the semiconductor substrate (10); and an edge termination structure portion (90) provided so as to enclose the active portion (120) in plan view of the semiconductor substrate; wherein the semiconductor substrate (10) comprises a through region (106) in which hydrogen implanted at a position of the second hydrogen concentration peak (141) has passed, wherein the through region (106) provided in the edge termination structure portion (90) is shorter in the depth direction than the through region (106) provided in the active portion (120) or the through region (106) is not provided in the edge termination structure portion (90).The semiconductor device (100) according to any one of claims 9 to 18, further comprising a transistor portion (70) and a diode portion (80) provided on the semiconductor substrate (10), wherein the semiconductor substrate (10) comprises a through region (106) in which hydrogen implanted at a position of the second hydrogen concentration peak (141) has passed, wherein the through region (106) provided in the diode portion (80) is shorter in the depth direction than the through region (106) provided in the transistor portion (70) or the through region (106) is not provided in the diode portion (80).The semiconductor device (100) according to any one of claims 9 to 18, further comprising a transistor portion (70) and a diode portion (80) provided on the semiconductor substrate (10), wherein the semiconductor substrate (10) comprises a through region (106) in which hydrogen implanted at a position of the second hydrogen concentration peak (141) has passed, wherein the through region (106) provided in the transistor portion (70) is shorter in the depth direction than the through region (106) provided in the diode portion (80) or the through region (106) is not provided in the transistor portion (70).The semiconductor device (100) according to any one of claims 9 to 20, wherein the first depth is included within a range of 5 μm or less from the bottom surface (23) in the depth direction.The semiconductor device (100) according to any one of claims 9 to 21, wherein a donor concentration at the first hydrogen concentration peak (131) is between 1×10 15 / cm 3 and 1×10 17 cm 3.The semiconductor device (100) according to any one of claims 1, 5, and 6, wherein a hydrogen concentration distribution in a depth direction connecting the top surface (21) and the bottom surface (23) of the semiconductor substrate includes a first hydrogen concentration peak (131) disposed within a range of 5 μm or less from the bottom surface (23) in the depth direction and a second hydrogen concentration peak (141) disposed closer to the top surface (21) than the first hydrogen concentration peak (131) and within a range 80 μm or more from the bottom surface (23) in the depth direction, and a minimum value of a donor concentration between a depth at which the first hydrogen concentration peak (131) is disposed and a depth at which the second hydrogen concentration peak (141) is disposed, greater than a donor concentration of the semiconductor substrate.The semiconductor device (100) according to claim 23, wherein the semiconductor substrate (10) has an impurity concentration peak between the bottom surface (23) and the first hydrogen concentration peak (131), and an impurity of the impurity concentration peak is argon or fluorine.The semiconductor device (100) according to any one of claims 1, 5, and 6, wherein a hydrogen concentration distribution in a depth direction connecting the top surface (21) and the bottom surface (23) of the semiconductor substrate has a first hydrogen concentration peak (131) disposed within a range of 5 μm or less from the bottom surface (23) in the depth direction and a second hydrogen concentration peak (141) disposed closer to the top surface (21) than the first hydrogen concentration peak (131), the semiconductor substrate (10) has an impurity concentration peak between the bottom surface (23) and the first hydrogen concentration peak (131), an impurity of the impurity concentration peak is argon or fluorine, and a concentration value of the impurity concentration peak is smaller than a concentration value of the first hydrogen concentration peak (131).The semiconductor device (100) according to claim 25, wherein the concentration value of the impurity concentration peak is less than or equal to one tenth of the concentration value of the first hydrogen concentration peak (131).A method for manufacturing the semiconductor device (100) according to claim 1, comprising: implanting hydrogen at a position closer to the top surface (21) than a region where the drift region (18) is to be formed from the bottom surface (23) of the semiconductor substrate to form a through region (106) in which the hydrogen has passed; and forming a hydrogen donor in the through region (106) by applying a heat treatment to the semiconductor substrate (10) such that the donor concentration of the drift region (18) is higher than the base doping concentration of the semiconductor substrate entirely across the drift region (18) in the depth direction.The method of claim 27, wherein implanting hydrogen comprises: first implanting hydrogen to a first depth from the bottom surface (23) of the semiconductor substrate; second implanting hydrogen to a second depth from the bottom surface (23) of the semiconductor substrate, the second depth being positioned closer to the top surface (21) than the region in which the drift region (18) is to be formed.The method of claim 28, wherein the first implanting includes implanting at least a minimum dose of hydrogen determined by a diffusion coefficient of hydrogen in the semiconductor substrate (10) and the second depth.The method according to claim 28 or 29, wherein the semiconductor substrate (10) is a silicon substrate, wherein assuming that the second depth from the bottom surface (23) is × (μm), a dose of hydrogen Q (ions / cm2) at the first implanting satisfies Q ≥ 2.6186 × 10 10 × e 0,12412x.The method of any of claims 28 to 30, wherein in the first implanting, hydrogen is implanted to the first depth by plasma doping.Method according to claim 31, wherein the bottom side (23) of the semiconductor substrate is ground after the plasma doping.Method according to claim 31, wherein the top side (21) of the semiconductor substrate is laser annealed after the plasma doping.The semiconductor device (100) according to claim 1, wherein the drift region (18) comprises hydrogen donors throughout the depth direction; and the donor concentration of the drift region (18) comprises the base doping concentration and a concentration of the hydrogen donors.

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