Semiconductor devices and methods for manufacturing semiconductor devices

Abstract

The present invention provides a semiconductor device comprising: a semiconductor substrate having an upper surface and a lower surface, and including bulk donors; a buffer zone of a first conductivity type disposed on the lower surface side of the semiconductor substrate, including hydrogen donors, and having a single first doping concentration peak in the depth direction of the semiconductor substrate; a high concentration region of the first conductivity type disposed between the buffer zone and the upper surface of the semiconductor substrate, including hydrogen donors, and having a donor concentration higher than the bulk donor concentration; and a lower surface region of the first conductivity type or a second conductivity type disposed between the buffer zone and the lower surface of the semiconductor substrate, having a doping concentration higher than the high concentration region.

Description

Technical Field

[0001] This invention relates to a semiconductor device and a method for manufacturing a semiconductor device. Background Technology

[0002] Previously, techniques for adjusting the doping concentration of semiconductor wafers by injecting hydrogen ions were known (see, for example, Patent Document 1).

[0003] Patent Document 1: US2015 / 0050754 Summary of the Invention

[0004] Technical issues

[0005] Preferably, hydrogen can be easily diffused to areas far from the hydrogen injection site.

[0006] Technical solution

[0007] To address the aforementioned issues, in one aspect of the present invention, a semiconductor device is provided. This semiconductor device includes a semiconductor substrate having an upper surface and a lower surface and containing bulk donors. The semiconductor device may include a buffer zone of a first conductivity type disposed on the lower surface side of the semiconductor substrate and containing hydrogen donors, with the doping concentration distribution in the depth direction of the semiconductor substrate having a single first doping concentration peak. The semiconductor device may include a high-concentration region of the first conductivity type disposed between the buffer zone and the upper surface of the semiconductor substrate, containing hydrogen donors, and the donor concentration being higher than the bulk donor concentration. The semiconductor device may include a lower surface region of either a first or second conductivity type disposed between the buffer zone and the lower surface of the semiconductor substrate, with a doping concentration higher than that of the high-concentration region.

[0008] The doping concentration peak in the buffer zone can be the concentration peak of hydrogen donors.

[0009] The doping concentration peak in the buffer can be the concentration peak of N-type dopants other than hydrogen donors.

[0010] The semiconductor device may have impurity chemical concentration peaks disposed on the upper surface side of the semiconductor substrate. The impurity chemical concentration at the upper edge of the impurity chemical concentration peak decreases from the apex towards the upper surface side, and the impurity chemical concentration at the lower edge of the impurity chemical concentration peak decreases more sharply than the impurity chemical concentration at the lower edge of the impurity chemical concentration peak. The high concentration region can be set from the doping concentration peak of the buffer zone to the impurity chemical concentration peak.

[0011] The semiconductor device may have a hydrogen chemical concentration peak positioned at the same depth as the first doping concentration peak in the buffer zone. The semiconductor device may also have a second doping concentration peak positioned at the same depth as the impurity chemical concentration peak. The impurity chemical concentration peak may be a hydrogen chemical concentration peak. Each concentration peak may have a downward slope where the concentration increases from the lower surface to the upper surface of the semiconductor substrate. The value obtained by normalizing the slope of the downward slope of the second doping concentration peak using the slope of the impurity chemical concentration peak's downward slope can be smaller than the value obtained by normalizing the slope of the downward slope of the first doping concentration peak using the slope of the hydrogen chemical concentration peak's downward slope.

[0012] The high-concentration region can have a length of more than 50% of the thickness of the semiconductor substrate in the depth direction.

[0013] The high-concentration region can have a length of more than 70 μm in the depth direction of the semiconductor substrate.

[0014] The donor concentration in the high-concentration region can be more than twice the volume donor concentration.

[0015] The donor concentration in the high-concentration zone can be more than 5 times the volume donor concentration.

[0016] With the rated voltage of the semiconductor device set to x (V), the bulk donor concentration (atoms / cm³) 3 ) can be (9.20245×10 12 ) / x or more and (4.60123×10 16 Below ) / x.

[0017] Organism donor concentration (atoms / cm) 3 ) can be (9.20245×10 14 ) / x or more and (1.84049×10 16 Below ) / x.

[0018] Donor concentration at the center of the depth direction of the semiconductor substrate ( / cm) 3 ) can be (9.20245×10 15 ) / x or more and (9.20245×10 16 Below ) / x.

[0019] In a second aspect of the invention, a method for manufacturing a semiconductor device is provided. The manufacturing method may include a first implantation stage in which charged particles are implanted from the lower surface of a semiconductor substrate having an upper surface and a lower surface and containing a bulk donor to a second location, and hydrogen ions are implanted to a first location to create a single peak in the hydrogen chemical concentration distribution in a region further down the surface than the second location. The manufacturing method may include a first annealing stage in which the semiconductor substrate is annealed to form a high-concentration region between the first and second locations where the donor concentration is higher than the bulk donor concentration.

[0020] The manufacturing method may include a grinding stage, after a first annealing stage, grinding the lower surface side of the semiconductor substrate to remove the region including the first location.

[0021] The manufacturing method may include a second implantation stage, after the grinding stage, implanting an N-type dopant from the lower surface of the semiconductor substrate to a position further down the surface than the second position.

[0022] The manufacturing method may include a second implantation stage, after the grinding stage, where hydrogen ions are implanted from the lower surface of the semiconductor substrate to a position further down the surface than the second position.

[0023] It should be noted that the above description of the invention does not list all the essential features of the invention. Furthermore, sub-combinations of these feature groups can also constitute separate inventions. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view showing an example of a semiconductor device 100.

[0025] Figure 2 Show Figure 1 The lattice defect density D at the depth direction indicated by line AA V Hydrogen chemical concentration C H Doping concentration D d and the chemical concentration of impurities C I The distribution of each.

[0026] Figure 3 The lattice defect density D of the comparative example is shown. V Hydrogen chemical concentration C H Doping concentration D d and the chemical concentration of impurities C I The distribution of each.

[0027] Figure 4 This is a flowchart illustrating an example of a method for manufacturing a semiconductor device 100.

[0028] Figure 5 This is a flowchart illustrating another example of a method for manufacturing a semiconductor device 100.

[0029] Figure 6 Yes Figure 5 The figure illustrates the semiconductor device 100 involved in the manufacturing method.

[0030] Figure 7 Show Figure 6 The lattice defect density D at the depth direction indicated by line AA V Hydrogen chemical concentration C H Doping concentration D d and the chemical concentration of impurities C I The distribution of each.

[0031] Figure 8 This is a graph showing other examples of the first doping concentration peak 111.

[0032] Figure 9A This is a graph illustrating the relationship between the hydrogen chemical concentration peak 131 and the first doping concentration peak 111.

[0033] Figure 9B This is a graph illustrating the relationship between the impurity chemical concentration peak 141 and the second doping concentration peak 121.

[0034] Figure 9C This diagram illustrates the tilt of the lower hem 142.

[0035] Figure 10A This diagram illustrates other definitions of the normalized inclination of the lower hem 112.

[0036] Figure 10B This diagram illustrates other definitions of the normalized inclination of the lower hem 122.

[0037] Figure 11 This is a graph showing the relationship between ε' and γ expressed by equation (12) for each β.

[0038] Figure 12 This shows the concentration of donor N in vivo. Bre A diagram illustrating an example of the preferred range.

[0039] Figure 13 This shows the bulk donor concentration N when ε' is in the range B (above 0.01 and below 0.333). Bre A diagram illustrating an example of the preferred range.

[0040] Figure 14 This shows the bulk donor concentration N when ε' is in the range C (above 0.03 and below 0.25). Bre A diagram illustrating an example of the preferred range.

[0041] Figure 15 This shows the bulk donor concentration N when ε' is in the range D (above 0.1 and below 0.2). Bre A diagram illustrating an example of the preferred range.

[0042] Figure 16 This shows the bulk donor concentration N when ε' is in the range E (above 0.001 and below 0.1). Bre A diagram illustrating an example of the preferred range.

[0043] Figure 17 This shows the bulk donor concentration N when ε' is in the range F (above 0.002 and below 0.05). Bre A diagram illustrating an example of the preferred range.

[0044] Figure 18 This shows the bulk donor concentration N when ε' is in the range G (above 0.005 and below 0.02). Bre A diagram illustrating an example of the preferred range.

[0045] Figure 19 This shows the bulk donor concentration N when ε' is in the range H (0.01 ± 0.002). Bre A diagram illustrating an example of the preferred range.

[0046] Figure 20 This is an example of a top view of a semiconductor device 100.

[0047] Figure 21 yes Figure 20 An enlarged view of region A in the image.

[0048] Figure 22A It is shown Figure 21 A diagram of an example of the bb section.

[0049] Figure 22B It is shown Figure 22A The doping concentration D at the dd line d The distribution of examples is shown in the figure.

[0050] Figure 23 It is shown Figure 21 Figures of other examples of the bb section.

[0051] Symbol Explanation

[0052] 10···Semiconductor substrate, 11···Well region, 12···Emitter region, 14···Base region, 15···Contact region, 16···Accumulation region, 18···Bulk donor region, 19···Drift region, 20···Buffer zone, 21···Upper surface, 22···Collector region, 23···Lower surface, 24···Collector, 29···Linear portion, 30···Dummy trench portion, 31···Front end portion, 32···Dummy insulating film, 34···Dummy conductive portion, 38···Interlayer insulating film, 39···Linear portion 40···Gate trench, 41···Front end, 42···Gate insulating film, 44···Gate conductive part, 52···Emitter, 54···Contact hole, 60, 61···Mesa section, 70···Transistor part, 80···Diode part, 81···Extended region, 82···Cathode region, 90···Edge termination structure, 92···Guard ring, 100···Semiconductor device, 102···End edge, 106···Through region, 111···First doping concentration peak, 112···Lower side edge, 1 13···Upper side swing, 114···Tilting angle, 117···Doping concentration peak, 119···Chemical concentration peak, 121···Second doping concentration peak, 122···Lower side swing, 123···Upper side swing, 124···Tilting angle, 125···Tilting angle, 129···Active side gate wiring, 130···Outer peripheral gate wiring, 131···Hydrogen chemical concentration peak, 132···Lower side swing, 133···Upper side swing, 134···Tilting angle, 137···Hydrogen chemical concentration peak, 141·· Impurity chemical concentration peak, 142...lower side swing, 143...upper side swing, 144...tilt, 145...tilt, 150...high concentration region, 160...active part, 164...gate pad, 181...low concentration region, 201...lower surface region, 211...first defect density peak, 212...second defect density peak, 213...defect density peak, 214...defect density peak, 311...upper limit, 312...lower limit, 313...upper limit, 314...lower limit Detailed Implementation

[0053] The present invention will now be described through embodiments thereof, but these embodiments do not limit the scope of the invention as defined in the claims. Furthermore, not all combinations of the features described in the embodiments are necessarily required for the technical solution of the invention.

[0054] In this specification, one side parallel to the depth direction of the semiconductor substrate is referred to as "upper," and the other side as "lower." Of the two main surfaces of a substrate, layer, or other component, one is referred to as the upper surface, and the other as the lower surface. The directions of "upper" and "lower" are not limited to the direction of gravity or the actual orientation of the semiconductor device during mounting.

[0055] In this specification, rectangular coordinate axes, namely the X-axis, Y-axis, and Z-axis, are sometimes used to illustrate technical matters. Rectangular coordinate axes merely determine the relative positions of constituent elements and do not limit specific directions. For example, the Z-axis does not necessarily represent the direction of height relative to the ground. It should be noted that the +Z-axis direction and the -Z-axis direction are opposite to each other. When the Z-axis direction is not specified as positive or negative, it refers to a direction parallel to both the +Z-axis and -Z-axis.

[0056] In this specification, orthogonal axes parallel to the upper and lower surfaces of the semiconductor substrate are designated as the X-axis and Y-axis. An axis perpendicular to the upper and lower surfaces of the semiconductor substrate is designated as the Z-axis. In this specification, the direction of the Z-axis is sometimes referred to as the depth direction. Additionally, in this specification, the direction including the X-axis and Y-axis and parallel to the upper and lower surfaces of the semiconductor substrate is sometimes referred to as the horizontal direction.

[0057] Additionally, the region extending from the center of the semiconductor substrate in the depth direction to the upper surface of the semiconductor substrate is sometimes referred to as the upper surface side. Similarly, the region extending from the center of the semiconductor substrate in the depth direction to the lower surface of the semiconductor substrate is sometimes referred to as the lower surface side. In this specification, the center position in the depth direction of the semiconductor substrate is sometimes referred to as Zc.

[0058] In this specification, the terms "same" or "equal" may also include cases with errors caused by manufacturing deviations, etc. Such errors are, for example, within 10%.

[0059] In this specification, the conductivity type of the doped region containing impurities is described as P-type or N-type. In this specification, impurities sometimes specifically refer to either an N-type donor or a P-type acceptor, and are sometimes referred to as dopant. In this specification, doping refers to introducing donors or acceptors into a semiconductor substrate to form a semiconductor exhibiting an N-type conductivity type or a P-type conductivity type.

[0060] In this specification, doping concentration refers to the concentration of donors or acceptors at thermal equilibrium. In this specification, net doping concentration refers to the actual concentration obtained by adding the polarities of the charges, with the donor concentration set to the concentration of positive ions and the acceptor concentration set to the concentration of negative ions. For example, if the donor concentration is set to N... D And set the acceptor concentration to NA Then the actual net doping concentration at any position becomes N. D -N A In this specification, the net doping concentration is sometimes described as the doping concentration only.

[0061] Donors have the function of supplying electrons to semiconductors. Acceptors have the function of taking electrons from semiconductors. Donors and acceptors are not limited to impurities themselves. For example, VOH defects formed by the combination of vacancies (V), oxygen (O), and hydrogen (H) present in semiconductors act as electron-supplying donors. In this specification, VOH defects are sometimes referred to as hydrogen donors.

[0062] In this specification, "P+" or "N+" indicates a higher doping concentration than "P" or "N" type, while "P-" or "N-" indicates a lower doping concentration than "P" or "N" type. Similarly, "P++" or "N++" indicates a higher doping concentration than "P+" or "N+" type. Unless otherwise stated, the units used in this specification are SI units. Although length is sometimes expressed in cm, all calculations should be converted to meters (m).

[0063] In this specification, chemical concentration refers to the atomic density of impurities measured independently of the electroactivated state. Chemical concentration (atomic density) can be measured using, for example, secondary ion mass spectrometry (SIMS). The net doping concentration described above can be measured using voltage-capacitance measurement (CV method). Alternatively, the carrier concentration measured using extended resistance measurement (SR method) can be used as the net doping concentration. The carrier concentration measured by CV or SR methods can be taken as the value under thermal equilibrium conditions. Furthermore, in the N-type region, the donor concentration is much greater than the acceptor concentration; therefore, the carrier concentration in this region can also be defined as the donor concentration. Similarly, in the P-type region, the carrier concentration in this region can also be defined as the acceptor concentration. In this specification, the doping concentration in the N-type region is sometimes referred to as the donor concentration, and the doping concentration in the P-type region is sometimes referred to as the acceptor concentration.

[0064] Furthermore, when the concentration distribution of donor, acceptor, or net dopant has a peak, the peak value can be taken as the concentration of donor, acceptor, or net dopant in that region. When the concentration of donor, acceptor, or net dopant is almost uniform, the average concentration of donor, acceptor, or net dopant in that region can also be taken as the concentration of donor, acceptor, or net dopant. In this specification, atoms / cm³ is sometimes used to express concentration per unit volume. 3 or / cm 3 This unit is used to indicate the concentration of donors or acceptors, or the chemical concentration, within a semiconductor substrate. The "atoms" designation can also be omitted.

[0065] The carrier concentration measured by the SR method can be lower than the donor or acceptor concentration. During the measurement of extended resistance, within the current flow range, there are cases where the carrier mobility of the semiconductor substrate is lower than the carrier mobility value in the crystalline state. This decrease in carrier mobility is due to the disorder (disorder) of the crystal structure caused by lattice defects, which disperses the carriers.

[0066] The donor or acceptor concentration calculated from the carrier concentration measured by the CV or SR method can be lower than the chemical concentration of the element representing the donor or acceptor. For example, in silicon semiconductors, the donor concentration of phosphorus or arsenic (which acts as a donor), or the acceptor concentration of boron (which acts as an acceptor), is approximately 99% of their chemical concentration. On the other hand, in silicon semiconductors, the donor concentration of hydrogen (which acts as a donor) is approximately 0.1% to 10% of the chemical concentration of hydrogen. The concentrations in this specification can be values ​​at room temperature. For example, values ​​at room temperature can be values ​​at 300 K (Kelvin) (approximately 26.9°C).

[0067] When charged particles such as ions or electrons are injected into a semiconductor substrate with a predetermined acceleration energy, these particles have a predetermined distribution in the depth direction. In this specification, the peak position of this distribution is sometimes referred to as the location where the particle is injected or the depth at which the particle is injected.

[0068] Figure 1 This is a cross-sectional view showing an example of a semiconductor device 100. The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 is a substrate formed of semiconductor material. As an example, the semiconductor substrate 10 is a silicon substrate.

[0069] At least one of a transistor element such as an insulated-gate bipolar transistor (IGBT) and a diode element such as a freewheeling diode (FWD) is formed on a semiconductor substrate 10. Figure 1 In this diagram, the electrodes of the transistor and diode elements and the regions disposed within the semiconductor substrate 10 are omitted. Examples of the configuration of the transistor and diode elements will be described later.

[0070] In this example, the semiconductor substrate 10 is uniformly distributed with N-type body donors. Body donors are formed during the fabrication of the ingot that forms the basis of the semiconductor substrate 10, by dopants that are contained substantially uniformly within the ingot. In this example, the body donors are elements other than hydrogen. While the dopants for body donors are, for example, phosphorus, antimony, arsenic, selenium, and sulfur, they are not limited to these. In this example, the body donor is phosphorus. Body donors are also contained within P-type regions. The semiconductor substrate 10 can be a wafer cut from a semiconductor ingot or a chip formed by monolithically stacking wafers. The semiconductor ingot can be manufactured using any of the following methods: Czochralski (CZ) method, magnetic Czochralski (MCZ) method, and floating zone melting (FZ) method. In this example, the ingot is manufactured using the MCZ method. The substrate manufactured using the MCZ method contains an oxygen concentration of 1 × 10⁻⁶. 17 ~7×10 17 / cm 3 The oxygen concentration in the substrate manufactured using the FZ method is 1 × 10⁻⁶. 15 ~5×10 16 / cm 3 High oxygen concentrations tend to promote the formation of hydrogen donors. The bulk donor concentration can be the chemical concentration of bulk donors distributed throughout the semiconductor substrate 10, or a value between 90% and 100% of that chemical concentration. Alternatively, the semiconductor substrate 10 can be an undoped substrate that does not contain dopants such as phosphorus. In this case, the bulk donor concentration of the undoped substrate is, for example, 1 × 10⁻⁶. 10 / cm 3 Above and 5×10 12 / cm 3 The bulk donor concentration of the undoped substrate is preferably 1×10⁻⁶. 11 / cm 3 The above. The preferred bulk donor concentration for the undoped substrate is 5 × 10⁻⁶. 12 / cm 3 the following.

[0071] The semiconductor substrate 10 has an upper surface 21 and a lower surface 23. The upper surface 21 and the lower surface 23 are the two main surfaces of the semiconductor substrate 10. In this specification, the orthogonal axes on the planes parallel to the upper surface 21 and the lower surface 23 are designated as the X-axis and the Y-axis, and the axis perpendicular to the upper surface 21 and the lower surface 23 is designated as the Z-axis.

[0072] Charged particles are implanted into the semiconductor substrate 10 from the lower surface 23 to a second depth position Z2. These charged particles are, for example, hydrogen ions, helium ions, electrons, etc. In this example, the semiconductor substrate 10 has an impurity chemical concentration peak 141 such as hydrogen or helium at the second depth position Z2. It should be noted that the second depth position Z2 can be a position higher than the upper surface 21. That is, charged particles can be implanted in a manner that penetrates the semiconductor substrate 10.

[0073] The depth position refers to the position in the depth direction (Z-axis direction) of the semiconductor substrate 10. In this specification, the distance from the lower surface 23 to each position is sometimes referred to as the depth position of each position. For example, the distance from the lower surface 23 to the second depth position Z2 is Z2. The second depth position Z2 can be disposed on the side of the upper surface 21 of the semiconductor substrate 10 (i.e., the region between the upper surface 21 and the central position Zc in the depth direction).

[0074] The average distance (also called range) that a charged particle travels through the interior of the semiconductor substrate 10 can be controlled by the acceleration energy used to accelerate the charged particle. In this example, the acceleration energy is set such that the average range of the charged particle is the distance Z2. The average range Z2 of the charged particle can be greater than half the thickness of the semiconductor substrate 10 in the depth direction.

[0075] In this specification, the region through which the injected charged particle passes is sometimes referred to as the passage region 106. Figure 1 In the example, the semiconductor substrate 10 extends from its lower surface 23 to the second depth position Z2 through region 106. Figure 1 In one example, charged particles are injected from the entire lower surface 23 of the semiconductor substrate 10. In other examples, charged particles may be injected only into a portion of the lower surface 23. This allows for the localization of the through region 106 in the XY plane.

[0076] An N-type buffer 20 is provided on the lower surface 23 side of the semiconductor substrate 10 (i.e., the region between the lower surface 23 and the central position Zc in the depth direction). A lower surface region 201 is provided between the buffer 20 and the lower surface 23. The lower surface region 201 is an N-type or P-type region with a higher doping concentration than the high-concentration region 150 described later. The lower surface region 201 can be a cathode region or a collector region described later. The buffer 20 suppresses the depletion layer extending from the upper surface 21 side of the semiconductor substrate 10 from reaching the lower surface region 201 (breakdown).

[0077] The doping concentration distribution in the depth direction of the semiconductor substrate 10 of the buffer 20 has a single first doping concentration peak 111. The first doping concentration peak 111 is located at a first depth position Z1. By setting the first doping concentration peak 111, it is possible to suppress the aforementioned depletion layer from extending beyond the first doping concentration peak 111 to the lower surface 23 side. The buffer 20 may contain hydrogen donors.

[0078] In this example, protons and other hydrogen ions are injected from the lower surface 23 to the first depth position Z1. In this example, between the first depth position Z1 and the second depth position Z2, no impurity ions other than the aforementioned hydrogen ions and charged particles are injected locally.

[0079] In the passage region 106 of the semiconductor substrate 10, where charged particles pass through, lattice defects, primarily composed of single-atom vacancies (V) and multi-atom vacancies (VV), are formed due to the passage of charged particles. Atoms adjacent to the vacancies have dangling bonds. Lattice defects also include interlattice atoms and / or dislocations, and in a broader sense, may include donors and / or acceptors. However, in this specification, lattice defects primarily composed of vacancies are sometimes referred to as vacancy-type lattice defects, or simply lattice defects. Furthermore, due to the formation of a large number of lattice defects by injecting charged particles into the semiconductor substrate 10, the crystallinity of the semiconductor substrate 10 becomes severely disordered. In this specification, this disordered crystallinity is sometimes referred to as disorder.

[0080] Furthermore, oxygen is present throughout the semiconductor substrate 10. This oxygen is intentionally or unintentionally introduced during the manufacture of the semiconductor ingot. Inside the semiconductor substrate 10, hydrogen (H), vacancies (V), and oxygen (O) combine to form VOH defects. Additionally, heat treatment of the semiconductor substrate 10 causes hydrogen implanted at the first depth position Z1 to diffuse, promoting the formation of VOH defects. When the charged particles implanted at the second depth position Z2 are hydrogen ions, hydrogen also diffuses from the second depth position Z2, further promoting the formation of VOH defects.

[0081] VOH defects function as electron donors. In this specification, VOH defects are sometimes referred to simply as hydrogen donors. In this example, hydrogen donors are formed in the passage region 106 of the charged particle. The doping concentration of the hydrogen donors is lower than the chemical concentration of hydrogen. If the ratio of the doping concentration of the hydrogen donors to the chemical concentration of hydrogen is defined as the activation rate, the activation rate can be a value from 0.1% to 30%. In this example, the activation rate is from 1% to 5%.

[0082] By forming hydrogen donors in the passage region 106 of the semiconductor substrate 10, it is possible to make the donor concentration in the passage region 106 higher than the bulk donor concentration. Typically, a semiconductor substrate 10 with a predetermined bulk donor concentration must be prepared, corresponding to the characteristics of the device to be formed on the semiconductor substrate 10, particularly its rated voltage or withstand voltage. In contrast, according to... Figure 1 The semiconductor device 100 shown can adjust the donor concentration of the semiconductor substrate 10 by controlling the dosage of charged particles and hydrogen ions. Therefore, the semiconductor device 100 can be manufactured using a semiconductor substrate 10 with a bulk donor concentration that does not correspond to the characteristics of the device. Although the deviation in bulk donor concentration during the manufacture of the semiconductor substrate 10 is relatively large, the dosage of charged particles and hydrogen ions can be controlled with relatively high precision. Therefore, the concentration of lattice defects generated by the implantation of charged particles can also be controlled with high precision, as can the concentration of hydrogen bound to lattice defects. Therefore, the donor concentration through region 106 can be controlled with high precision.

[0083] Furthermore, the hydrogen injected into the first depth position Z1 preferably diffuses towards the upper surface 21 to a more distant position. As a result, the length through the Z-axis of the region 106 can be increased, making it easier to cover a wide area of ​​the semiconductor substrate 10 and adjust the doping concentration.

[0084] If impurities other than hydrogen ions and charged particles are injected between the first depth position Z1 and the second depth position Z2, a large number of lattice defects will form near the injection position. In the region where a large number of lattice defects are formed, the diffusion of hydrogen ions is suppressed. Therefore, if there is a region with a high density of lattice defects between the first depth position Z1 and the second depth position Z2, the diffusion of hydrogen ions will be suppressed.

[0085] Typically, buffer 20 is configured with multiple doping concentration peaks to suppress the expansion of the depletion layer while suppressing electric field concentration. To prevent the depletion layer from reaching the lower surface region 201, the doping concentration peak closest to the lower surface 23 is set as the maximum concentration among the multiple doping concentration peaks. However, if buffer 20 is configured with multiple doping concentration peaks and hydrogen donors are formed in the passage region 106, the diffusion of hydrogen injected into the maximum concentration peak of buffer 20 will be hindered by lattice defects formed at the locations of other doping concentration peaks. Therefore, sometimes hydrogen does not diffuse throughout the entire passage region 106.

[0086] In this example, buffer 20 has a single first doping concentration peak 111. Therefore, hydrogen diffusion is not suppressed, at least within buffer 20. Consequently, hydrogen injected into the first depth position Z1 readily diffuses toward the upper surface 21.

[0087] Figure 2 Show Figure 1 The lattice defect density D in the depth direction at the location indicated by line AA V Hydrogen chemical concentration C H Doping concentration D d and the chemical concentration of impurities C I The distribution of each component. In this example, the impurities are helium or hydrogen. Figure 2 The horizontal axis represents the depth position 23 from the lower surface, and the vertical axis represents the chemical concentration of hydrogen, donor concentration, and impurity chemical concentration per unit volume in logarithmic form. Figure 2 The lattice defect density D in the distribution V The first concentration represents the distribution before annealing, while the other concentrations represent the distribution after annealing following the introduction of hydrogen ions and charged particles (impurities).

[0088] Figure 2 The chemical concentrations of hydrogen and impurities are measured, for example, by the SIMS method. Figure 2The doping concentration in the figure is, for example, the electroactive doping concentration measured by the CV method or the SR method.

[0089] In this example, the hydrogen chemical concentration C H The hydrogen chemical concentration peak 131 is located at the first depth position Z1. The hydrogen chemical concentration peak 131 exhibits a maximum value at the first depth position Z1.

[0090] In this example, the chemical concentration of the impurities is C. I At the second depth position Z2, there is an impurity chemical concentration peak 141. The impurity chemical concentration peak 141 exhibits a maximum value at the second depth position Z2.

[0091] Doping concentration D d It has a first doping concentration peak 111 and a second doping concentration peak 121. Additionally, the doping concentration D... d The lower surface region 201 can have a doping concentration peak. In this example, the lower surface region 201 has a P-type doping concentration peak. A P-type dopant such as boron can be implanted into the lower surface region 201. In other examples, the lower surface region 201 can have an N-type doping concentration peak. In this case, an N-type dopant such as phosphorus can be implanted into the lower surface region 201.

[0092] In this example, the first doping concentration peak 111 is the concentration peak of hydrogen donors (VOH defects) formed by the combination of lattice defects caused by the injection of hydrogen ions into the first depth position Z1 and the hydrogen injected into the first depth position Z1. Therefore, the first doping concentration peak 111 exhibits a maximum value at the first depth position Z1.

[0093] The second doping concentration peak 121 is the concentration peak of hydrogen donors formed by the combination of lattice defects caused by the injection of charged particles into the second depth position Z2 and hydrogen diffused from the first depth position Z1. Therefore, the second doping concentration peak 121 exhibits a maximum value at the second depth position Z2.

[0094] It should be noted that the location where the first doping concentration peak 111 reaches its maximum value may not strictly coincide with the first depth position Z1. For example, if the location where the first doping concentration peak 111 reaches its maximum value is included within the full width at half maximum (FWHM) of the first hydrogen chemical concentration peak 131 relative to the first depth position Z1, then the first doping concentration peak 111 can be considered substantially located at the first depth position Z1. Similarly, if the location where the second doping concentration peak 121 reaches its maximum value is included within the full FWHM of the impurity chemical concentration peak 141 relative to the second depth position Z2, then the second doping concentration peak 121 can be considered substantially located at the second depth position Z2.

[0095] In addition, if the first doping concentration peak 111 overlaps with the doping concentration peak of the lower surface region 201 and it is difficult to distinguish the first doping concentration peak 111, the doping concentration at the depth position Z1 of the apex of the hydrogen chemical concentration peak 131 can also be taken as the first doping concentration peak 111.

[0096] Each concentration peak has a lower sag (concentration decreases from the apex towards the lower surface 23) and an upper sag (concentration decreases from the apex towards the upper surface 21). In this example, the hydrogen chemical concentration peak 131 has a lower sag 132 and an upper sag 133. The impurity chemical concentration peak 141 has a lower sag 142 and an upper sag 143. The first doping concentration peak 111 has a lower sag 112 and an upper sag 113. The second doping concentration peak 121 has a lower sag 122 and an upper sag 123.

[0097] Since hydrogen ions are injected from the lower surface 23 at the first depth position Z1, a relatively large amount of hydrogen exists between the first depth position Z1 and the lower surface 23. Similarly, a large amount of impurities injected as charged particles exists between the second depth position Z1 and the lower surface 23. Therefore, in each concentration peak of each chemical concentration distribution, the concentration at the upper edge can decrease more sharply compared to the concentration at the lower edge. In addition, since the doping concentration depends on the hydrogen chemical concentration or the impurity chemical concentration, in each doping concentration peak, the concentration at the upper edge can also decrease more sharply compared to the concentration at the lower edge.

[0098] A relatively large number of lattice defects are formed by injecting hydrogen ions or charged particles near the first depth position Z1 and the second depth position Z2. Therefore, the lattice defect density D V A first defect density peak 211 is present at the first depth position Z1, and a second defect density peak 212 is present at the second depth position Z2. Additionally, the passage region 106 (see reference) extends from the second depth position Z2 to the lower surface 23. Figure 1 Except for the vicinity of the first depth position Z1 and the second depth position Z2, lattice defects caused by the passage of charged particles are formed at a roughly uniform density. Figure 2 Lattice defect density D V The distribution diagram shows the lattice defect density D as indicated by the dashed line. V The density can increase gradually towards peak 212 within a range not exceeding peak 212. At this point, the lattice defect density D... V With the increase in the orientation towards peak 212, lattice defects generated by the passage of charged particles can also form at a roughly uniform density.

[0099] Hydrogen injected into the first depth position Z1 diffuses toward the upper surface 21 through annealing. In this example, the buffer 20 has a single first doping concentration peak 111. Therefore, there are no defect density peaks other than the first defect density peak 211 in the buffer 20. Therefore, hydrogen easily diffuses from the first depth position Z1 to the second depth position Z2. VOH defects (hydrogen donors) are formed in the region formed by the diffusion of hydrogen at a concentration above a certain concentration in region 106, and a high-concentration region 150 containing hydrogen donors is formed. The high-concentration region 150 is where the donor concentration is higher than the bulk donor concentration D. b A higher concentration region. The high concentration region 150 is disposed between the buffer zone 20 and the upper surface 21 of the semiconductor substrate 10.

[0100] The high-concentration region 150 can be a region where the doping concentration is approximately uniform along the depth direction. Approximately uniform doping concentration along the depth direction can refer to, for example, a region where the difference between the maximum and minimum doping concentrations is within 50% of the maximum doping concentration, continuing continuously along the depth direction. This difference can be less than 30% or less than 10% of the maximum doping concentration in that region.

[0101] Alternatively, the value of the doping concentration distribution, relative to the average concentration of the doping concentration distribution within a predetermined range in the depth direction, can be within ±50%, ±30%, or ±10% of the average concentration of the doping concentration distribution. As an example, the predetermined range W in the depth direction can be as follows: that is, the length from the first depth position Z1 to the second depth position Z2 can be set as Z. L And from the center Z between Z1 and Z2 12 c moves 0.25Z away from both the first depth position Z1 and the second depth position Z2. L The length between the two points is 0.5Z. L The interval is set to this range. Based on the length of the high-concentration region 150, the length of the predetermined range can be set to 0.75Z. L It can also be set to 0.3Z L It can also be set to 0.9Z L The end position of the upper surface 21 side of the buffer 20 can also be the depth position where the approximately uniform doping concentration in the high concentration region 150 begins to monotonically increase toward the first doping concentration peak 111.

[0102] It should be noted that at doping concentration D d In the distribution measurement results, even in regions without dopant implantation, there may be small peaks due to noise during measurement. In this example, the doping concentration D d The peak can refer to the doping concentration D within a length of 10 μm. dA peak whose minimum to maximum value ratio is 1.1 or greater. This ratio can be 1.2 or greater, or 1.5 or greater. Similarly, a peak for each chemical concentration can also refer to a peak with this ratio.

[0103] Furthermore, it is preferable that there are no doping concentration peaks other than the first doping concentration peak 111 and the second doping concentration peak 121 between the first depth position Z1 and the second depth position Z2. Furthermore, it is preferable that there are no chemical concentration peaks other than the hydrogen chemical concentration peak 131 and the impurity chemical concentration peak 141 between the first depth position Z1 and the second depth position Z2. Furthermore, it is preferable that there are no defect density peaks other than the first defect density peak 211 and the second defect density peak 212 between the first depth position Z1 and the second depth position Z2. Therefore, hydrogen can easily diffuse from the first depth position Z1 to the second depth position Z2.

[0104] Because hydrogen diffuses easily, a high-concentration region 150 can easily form over a relatively long distance in the depth direction. The high-concentration region 150 can be continuously set from the first doping concentration peak 111 to the impurity chemical concentration peak 141. The high-concentration region 150 can also be continuously set from the upper end of the buffer zone 20 to the second depth position Z2.

[0105] The length of the high-concentration region 150 in the depth direction can be 50% or more, 60% or more, 70% or more, or 80% or more of the thickness of the semiconductor substrate 10 in the depth direction. Furthermore, the length of the high-concentration region 150 in the depth direction can be 70 μm or more, 80 μm or more, 90 μm or more, or 100 μm or more. In this example, since hydrogen easily diffuses to the second depth position Z2, the range of the high-concentration region 150 can be easily defined at the second depth position Z2.

[0106] The minimum donor concentration in the high-concentration region 150 is higher than the bulk donor concentration D of the semiconductor substrate 10. b That is, throughout the entire high-concentration region 150, the donor concentration (or doping concentration) in the high-concentration region 150 is higher than the bulk donor concentration D. b The donor concentration in the high-concentration region 150 is determined by the sum of the bulk donor concentration and the hydrogen donor concentration (VOH defect concentration). The hydrogen donor concentration can be precisely controlled by the dosage of charged particles at the second depth position Z2 and the dosage of hydrogen ions at the first depth position Z1. Therefore, by making the hydrogen donor concentration much higher than the bulk donor concentration, the deviation of the donor concentration in the high-concentration region 150 can be reduced even if there is a deviation in the bulk donor concentration. The donor concentration in the high-concentration region 150 can be the bulk donor concentration D. b It can be more than 2 times, or more than 5 times, or even more than 10 times.

[0107] Figure 3 The lattice defect density D of the comparative example is shown. V Hydrogen chemical concentration C H Doping concentration D d and the chemical concentration of impurities C I The distribution of each doping concentration peak. In the comparative example semiconductor device, in buffer 20, there is more than one doping concentration peak 117 located on the upper surface 21 side above the first doping concentration peak 111. As an example, each doping concentration peak 117 is formed by injecting hydrogen ions.

[0108] In this example, the hydrogen chemical concentration C H A hydrogen chemical concentration peak 137 is located at the same depth as the respective doping concentration peak 117. Additionally, the lattice defect density D... V A defect density peak 213 is present at the same depth position as each hydrogen chemical concentration peak 137. That is, the buffer zone 20 has more than one defect density peak 213 at a position on the upper surface 21 side than the first depth position Z1.

[0109] exist Figure 3 In the example, the concentration of hydrogen chemical concentration peak 131 is more than 10 times higher than that of other hydrogen chemical concentration peaks 137. Therefore, almost all the hydrogen diffusing from the buffer zone 20 to the upper surface 21 is hydrogen injected into the first depth position Z1. However, the diffusion of hydrogen injected into the first depth position Z1 is hindered by the defect density peak 213. For example, hydrogen is hindered by its combination with lattice defects or by the presence of lattice defects.

[0110] Therefore, in Figure 3 In this example, hydrogen cannot diffuse sufficiently to the second depth position Z2. In this case, the high-concentration region 150 does not form to the second depth position Z2, resulting in a residual low-concentration region 181 with a low donor concentration. The donor concentration of the low-concentration region 181 can be compared with the bulk donor concentration D. b The concentrations are similar. Furthermore, in cases where a large number of lattice defects remain in the low-concentration region 181, the carrier concentration in the low-concentration region 181 is sometimes higher than the bulk donor concentration D. b Low. Since almost no hydrogen donors are formed in the low concentration region 181, the influence of the bulk donor concentration on the donor concentration in the low concentration region 181 becomes greater. Therefore, this results in a relatively large deviation in the donor concentration of the low concentration region 181. Furthermore, since valley-like portions are generated in the doping concentration distribution, this sometimes affects the characteristics of the semiconductor device 100. In contrast, according to... Figure 2 The semiconductor device 100 shown can form a high concentration region 150 over a relatively wide area, thus suppressing deviations in doping concentration. In addition, the characteristics of the semiconductor device 100 can be adjusted with high precision.

[0111] It should be noted that, within buffer zone 20, the hydrogen chemical concentration peak 137 closest to the upper surface 21 is also considered to be of high concentration. This facilitates hydrogen diffusion to positions near the upper surface 21. However, if the hydrogen chemical concentration peak 137 near the upper surface 21 is set to a high concentration, under conditions of relatively high emitter-collector voltage, the depletion layer may sometimes reach a high doping concentration peak, reducing avalanche tolerance. According to... Figure 2 The example shown allows for the formation of a high-concentration region 150 near the upper surface 21 while suppressing the decrease in avalanche tolerance by positioning a high-concentration first dopant peak 111 near the lower surface 23. The distance between the first depth position Z1 and the lower surface 23 can be less than 5 μm or less than 3 μm.

[0112] Figure 4 This is a flowchart illustrating an example of a method for manufacturing a semiconductor device 100. First, in the upper surface-side structure formation stage S400, a structure is formed on the upper surface 21 side of the semiconductor substrate 10. The structure on the upper surface 21 side refers to at least a portion of the gate trench, dummy trench, emitter region, base region, accumulation region, interlayer insulating film, emitter, and gate wiring, which will be described later. All of these structures may also be formed in the upper surface-side structure formation stage S400.

[0113] Next, in the grinding stage S402, the thickness of the semiconductor substrate 10 is adjusted by grinding the lower surface 23 side of the semiconductor substrate 10. In the grinding stage S402, the thickness of the semiconductor substrate 10 can be adjusted according to the voltage withstand capability that the semiconductor device 100 should have.

[0114] Next, in the lower surface region formation stage S404, a lower surface region 201 is formed in the region that contacts the lower surface 23 of the semiconductor substrate 10. In the lower surface region formation stage S404, the lower surface region 201 can be formed by implanting an N-type dopant or a P-type dopant from the lower surface 23 and by performing local annealing on the vicinity of the lower surface 23 using a laser or the like.

[0115] Next, in the first implantation stage S406, charged particles and hydrogen ions are implanted into the semiconductor substrate 10. The first implantation stage S406 includes a charged particle implantation stage S408 and a hydrogen implantation stage S410. In the charged particle implantation stage S408, charged particles are implanted from the lower surface 23 of the semiconductor substrate 10 to a second depth position Z2. The charged particles can be hydrogen ions, helium ions, or an electron beam. In the hydrogen implantation stage S410, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 to a first depth position Z1. In the hydrogen implantation stage S410, hydrogen ions are implanted into the first depth position Z1 in a region further below the lower surface 23 than the second depth position Z2, in a manner that creates a single peak in the hydrogen chemical concentration distribution. It should be noted that when hydrogen ions are implanted into the second depth position Z2, a peak in the hydrogen chemical concentration may exist at the second depth position Z2. Either the charged particle implantation stage S408 or the hydrogen implantation stage S410 can be performed first.

[0116] Next, in annealing stage S412, the semiconductor substrate 10 is annealed. In annealing stage S412, the semiconductor substrate 10 is placed in an annealing furnace, and the entire semiconductor substrate 10 is annealed. A high-concentration region 150 is formed between the first depth position Z1 and the second depth position Z2 through annealing stage S412. Annealing stage S412 is preferably performed under conditions where the hydrogen injected into the first depth position Z1 can diffuse to the second depth position Z2. For example, the annealing temperature in annealing stage S412 is 350°C or higher and 400°C or lower. The annealing temperature can be 360°C or higher or 380°C or lower. The annealing time in annealing stage S412 can be 30 minutes or more, 1 hour or more, or 3 hours or more. The annealing time can be 10 hours or less or 7 hours or less.

[0117] Next, in the lower surface side electrode formation stage S414, a metal electrode is formed on the lower surface 23 of the semiconductor substrate 10. This metal electrode may be a collector electrode as described later. Alternatively, between the annealing stage S412 and the lower surface side electrode formation stage S414, impurities such as helium may be injected into the semiconductor substrate 10 to locally form lattice defects and adjust the carrier lifetime.

[0118] Figure 5 This is a flowchart illustrating another example of a method for manufacturing a semiconductor device 100. The manufacturing method in this example is relative to... Figure 4 The example shown differs in that it also includes a grinding stage S500, a second injection stage S502, and a second annealing stage S504. Other processes may be the same as... Figure 4 The example shown is the same. However, in this example, the lower surface region formation stage S404 is not performed before the first injection stage S406.

[0119] In this example, after the first annealing stage S412, the lower surface 23 side of the semiconductor substrate 10 is ground in the grinding stage S500. In the grinding stage S500, the lower surface 23 is ground in a manner that removes the region including the first depth position Z1 from the semiconductor substrate 10. In the grinding stage S500, grinding can be performed such that a portion of the upper lower edge 113 of the first doping concentration peak 111 remains on the semiconductor substrate 10, or grinding can be performed such that the upper lower edge 113 does not remain on the semiconductor substrate 10. In the grinding stage S500, the semiconductor substrate 10 can be ground such that the high concentration region 150 is exposed on the lower surface 23.

[0120] In this example, the thickness of the semiconductor substrate 10 ground by grinding stages S402 and S500 is a thickness corresponding to a preset withstand voltage. The grinding amount in grinding stages S402 and S500 can be arbitrarily set. Grinding stage S402 can also be omitted. Next, in the lower surface region forming stage S404, the lower surface region 201 is formed.

[0121] Next, in the second implantation stage S502, an N-type dopant is implanted into the third depth position Z3. The third depth position Z3 is the location where the buffer zone 20 should be formed. The N-type dopant can be hydrogen or a dopant other than hydrogen, such as phosphorus.

[0122] Next, in the second annealing stage S504, the semiconductor substrate 10 is annealed. In the second annealing stage S504, the N-type dopant implanted at the third depth position Z3 is activated and donor-ized. This allows the buffer zone 20 to be formed. In the second annealing stage S504, the entire semiconductor substrate 10 can be annealed, or only a portion can be annealed. Next, in the lower surface side electrode formation stage S414, a metal electrode is formed on the lower surface 23 of the semiconductor substrate 10.

[0123] Figure 6 Yes Figure 5 The figure illustrates the semiconductor device 100 involved in the manufacturing method. The lower surface of the semiconductor substrate 10 before grinding in the grinding stage S500 is designated as lower surface 23-2, and the lower surface after grinding is designated as lower surface 23-1.

[0124] In the first injection stage S406, hydrogen ions are injected from the lower surface 23-2 to the first depth position Z1, and charged particles are injected from the lower surface 23-2 to the second depth position Z2. Additionally, the hydrogen injected to the first depth position Z1 is diffused through the first annealing stage S412.

[0125] Next, in the grinding stage S500, the lower surface 23-2 is ground to remove the region including the first depth position Z1. Then, in the lower surface region forming stage S404, the lower surface region 201 is formed in the region that contacts the lower surface 23-1.

[0126] Next, in the second implantation stage S502, an N-type dopant is implanted into the third depth position Z3. Then, in the second annealing stage S504, the semiconductor substrate 10 is annealed to activate the N-type dopant implanted into the third depth position Z3, forming a buffer zone 20.

[0127] Figure 7 Show Figure 6 The lattice defect density D at the depth direction indicated by line AA V Hydrogen chemical concentration C H Doping concentration D d and the chemical concentration of impurities C I The distribution of each component. In this example, the impurities are helium or hydrogen. Figure 7 The lattice defect density D in the distribution V This represents the lattice defect density formed when hydrogen ions are injected into the first depth position Z1, the second depth position Z2, and the third depth position Z3. That is, the lattice defect density D. V The lattice defects formed during the formation of the lower surface region 201 are omitted. Figure 2 Similarly, the lattice defect density D V It can increase gradually towards peak 212 within a range not exceeding peak 212. Figure 7 In the diagram, dashed lines are used to represent the lattice defect density D. V The way it increases. At such a lattice defect density D V As the direction of peak 212 increases, lattice defects generated by the passage of charged particles can also form at a substantially uniform density. Additionally, the density of lattice defects that have been hydrogen-donated through annealing is also shown. Concentrations other than the lattice defect density are shown as the distribution after performing the second annealing stage S504.

[0128] At the first depth position Z1, a high concentration of hydrogen is injected to allow hydrogen to diffuse to the second depth position Z2. Therefore, this can sometimes result in a higher concentration of hydrogen donors at the first depth position Z1 than the concentration that buffer zone 20 should have.

[0129] In this example, after the hydrogen injected into the first depth position Z1 diffuses, the region including the first depth position Z1 is ground through a grinding stage S500. Then, an N-type dopant of the appropriate concentration for the buffer 20 is injected into the third depth position Z3. This facilitates the formation of a high-concentration region 150 over a wide range while simultaneously forming a buffer 20 of appropriate concentration. It should be noted that at the third depth position Z3, a defect density peak 214 is formed by the injection of the N-type dopant. However, since the formation of the defect density peak 214 occurs after the first annealing stage S412, it does not hinder the diffusion of hydrogen injected into the first depth position Z1.

[0130] In this example, the hydrogen chemical concentration peak 131 at the first depth position Z1 was removed. The hydrogen chemical concentration C... H It gradually decreases from the lower surface 23 toward the second depth position Z2.

[0131] exist Figure 7 In the example, an N-type dopant other than hydrogen was implanted into the third depth position Z3. That is, the first doping concentration peak 111 is the concentration peak of the N-type dopant other than the hydrogen donor. In other examples, hydrogen can also be implanted into the third depth position Z3. In this case, the first doping concentration peak 111 is the concentration peak of the hydrogen donor. Additionally, the hydrogen chemical concentration C... H A chemical concentration peak (not shown) is present at the first depth position Z1.

[0132] Figure 8 This is a graph illustrating another example of the first doping concentration peak 111. The first doping concentration peak 111 in this example can be applied to... Figures 1 to 7 The examples described herein. In this example, the first doping concentration peak 111 is a concentration peak containing both hydrogen donors and N-type dopants other than hydrogen donors. As an example, the N-type dopant is phosphorus. In other examples, the N-type dopant is selenium or arsenic.

[0133] In this example, phosphorus is implanted from the lower surface 23 to a first depth position Z1 to form a first doping concentration peak 111. Figure 8 In the diagram, the dashed line represents the chemical concentration of phosphorus, C. P Phosphorus chemical concentration C P A chemical concentration peak 119 is present at the first depth position Z1. Furthermore, the doping concentration D, which represents the donor concentration for phosphorus activation, is indicated by a dashed line. P Doping concentration D P It is the phosphorus chemical concentration C P The concentration is obtained by multiplying by the activation rate of phosphorus. The activation rate of phosphorus can be set to 1. In this case, the phosphorus chemical concentration C can be used. P As doping concentration D P .

[0134] The doping concentration D1 of the first doping concentration peak 111 is approximately equal to the phosphorus chemical concentration C. P The corresponding doping concentration D P The concentration of hydrogen donors, D H and the concentration of donor D b The sum. Hydrogen can be implanted at a first depth position Z1 in the semiconductor substrate 10. In this case, the hydrogen chemical concentration C... H A peak is observed at the first depth position Z1. In other examples, the hydrogen chemical concentration C... H The peak may not be present at the first depth position Z1. For example, the first doping concentration peak 111 may also be as follows. Figure 7 As shown, hydrogen donors are formed by the diffusion of hydrogen injected into the grinding area.

[0135] Furthermore, the implantation of N-type dopants such as phosphorus can be performed after the implantation of hydrogen ions. In this case, it is preferable to locally anneal the vicinity of the first depth position Z1 using a laser or the like after the N-type dopant implantation. This can suppress the reduction of hydrogen donors contained in the semiconductor substrate 10.

[0136] Figure 9A This is a graph illustrating the relationship between the hydrogen chemical concentration peak 131 and the first doping concentration peak 111. In this example, the slope 114 of the lower edge 112 of the first doping concentration peak 111 is normalized using the slope 134 of the lower edge 132 of the hydrogen chemical concentration peak 131. As an example, normalization is the process of dividing the slope 114 by the slope 134.

[0137] The tilt angle of the lower edge can be the tilt angle between the position where the concentration reaches a maximum value and the position where the concentration relative to the maximum value becomes a predetermined ratio. The predetermined ratio can be 80%, 50%, 10%, 1%, or other ratios. In addition, the tilt angle of the concentration distribution between the first depth position Z1 and the lower surface 23 of the semiconductor substrate 10 can also be used in the hydrogen chemical concentration peak 131 and the first doping concentration peak 111.

[0138] exist Figure 9AIn the example shown, the slope 134 of the hydrogen chemical concentration peak 131 is given by (H1-aH1) / (Z1-Z4), and the slope 114 of the first doping concentration peak 111 is given by (D1-aD1) / (Z1-Z5). H1 is the hydrogen chemical concentration at the first depth position Z1, D1 is the doping concentration at the first depth position Z1, 'a' is a pre-set ratio, Z4 is the depth at which the hydrogen concentration in the lower edge 132 of the hydrogen chemical concentration peak 131 becomes aH1, and Z5 is the depth at which the doping concentration in the lower edge 112 of the first doping concentration peak 111 becomes aD1. For example, if the slope 114 is normalized using the slope 134, it becomes (D1-aD1)(Z1-Z4) / {(H1-aH1)(Z1-Z5)}. The slope obtained by normalizing the slope 114 using the slope 134 is set as α.

[0139] Figure 9B This is a graph illustrating the relationship between the impurity chemical concentration peak 141 and the second doping concentration peak 121. In this example, hydrogen ions are injected as charged particles at the second depth position Z2. In this example, the tilt 124 of the lower swing 142 of the impurity chemical concentration peak 141 is normalized by the tilt 144 of the lower swing 142 of the second doping concentration peak 121.

[0140] exist Figure 9B In the example shown, the slope 144 of the impurity chemical concentration peak 141 is given by (H2-aH2) / (Z2-Z6), and the slope 124 of the second doping concentration peak 121 is given by (D2-aD2) / (Z2-Z7). H2 is the hydrogen chemical concentration at the second depth position Z2, D2 is the doping concentration at the second depth position Z2, a is a pre-set ratio, Z6 is the depth at which the hydrogen chemical concentration becomes aH2 in the lower edge 142 of the impurity chemical concentration peak 141, and Z7 is the depth at which the doping concentration becomes aD2 in the lower edge 122 of the second doping concentration peak 121. The ratio a used to normalize the slope of the second doping concentration peak 121 can be the same as or different from the ratio a used to normalize the slope of the first doping concentration peak 111. For example, if we normalize the tilt 124 using the tilt 144, it becomes (D2-aD2)(Z2-Z6) / {(Z2-Z7)(H2-aH2)}. Let the tilt obtained by normalizing the tilt 124 using the tilt 144 be β.

[0141] The normalized slope β of the lower edge 122 of the second doping concentration peak 121 is less than the normalized slope α of the lower edge 112 of the first doping concentration peak 111. That is, compared with the first doping concentration peak 111, the second doping concentration peak 121 is a flatter peak relative to the hydrogen chemical concentration peak. By implanting hydrogen ions in a manner that forms such a second doping concentration peak 121, a high concentration region 150 with a flat concentration distribution can be formed. In addition, by setting the second doping concentration peak 121 to a flat shape, the change in doping concentration at the leading edge of the high concentration region 150 can also be made gentler. The normalized slope β of the lower edge 122 of the second doping concentration peak 121 can be less than 1 times, less than 0.1 times, or less than 0.01 times the normalized slope α of the lower edge of the first doping concentration peak 111.

[0142] Furthermore, the inclination 144 of the lower sill 142 of the impurity chemical concentration peak 141 can be smaller than the inclination 145 of the upper sill 143. The chemical concentration distribution of hydrogen injected from the lower surface 23 to a deeper location sometimes results in a gentle sill on the lower surface 23 side. Therefore, by comparing the inclination 144 of the lower sill 142 with the inclination 145 of the upper sill 143, it can sometimes be determined whether the hydrogen injected to the second depth position Z2 was injected from the lower surface 23 side. The inclination 145 is given by (H2-aH2) / (Z8-Z2). The inclination 125 is given by (D2-aD2) / (Z9-Z2). Z8 is the depth at which the hydrogen chemical concentration in the upper sill 143 of the impurity chemical concentration peak 141 becomes aH2, and Z9 is the depth at which the doping concentration in the upper sill 123 of the second doping concentration peak 121 becomes aD2. It should be noted that in Figure 9B In the second doping concentration peak 121, although the tilt angle 124 of the lower side 122 is greater than the tilt angle 125 of the upper side 123, it can also be the same as the impurity chemical concentration peak 141, where the tilt angle 124 of the lower side 122 of the second doping concentration peak 121 is smaller than the tilt angle 125 of the upper side 123.

[0143] Figure 9C This diagram illustrates the inclination of the lower hem 142. The inclination of the lower hem 142 can also be considered as follows: [Example diagram would be inserted here]. Figure 9CAs described, in the impurity chemical concentration peak 141, the width (10% full width) between the two positions Z10 and Z11 that will result in a concentration of 10% (0.1 × H2) of the peak concentration H2 is set as FW10%M. The two positions Z10 and Z11 are the two positions closest to the second depth position Z2, separated by a second depth position Z2, among the points where the hydrogen chemical concentration is 0.1 × H2. The position on the side of the hydrogen chemical concentration peak 131 in the two positions Z10 and Z11 is set as Z10. The slope of the doping concentration at position Z10 is approximately flat. The slope of the hydrogen chemical concentration at position Z10 is more than 100 times the slope of the doping concentration at position Z10. For example, the slope of the hydrogen chemical concentration at position Z10 can be more than 100 times, or even more than 1000 times, the slope of the doping concentration at position Z10.

[0144] Figure 10A This diagram illustrates another definition for the normalization of the tilt angle of the lower hem 112. In the normalization of the tilt angle of the lower hem 112, for example, the following index γ is introduced. Figure 9A In the example, although positions Z4 and Z5 are different, in this example, positions Z4 and Z5 are set to the same position (Z4 = Z5). Position Z4 is a pre-defined position. Position Z4 is determined by the hydrogen chemical concentration C. H and doping concentration D d Positions 132 and 112 are located on the lower surface 23 side, which is lower than the first depth position Z1. The hydrogen chemical concentration at position Z4 is defined as a × H1, and the doping concentration as b × D1. a is the ratio of the hydrogen chemical concentration at position Z4 to the concentration H1 of the hydrogen chemical concentration peak 131 at the first depth position Z1. b is the ratio of the doping concentration at position Z4 to the concentration D1 of the first doping concentration peak 111 at the first depth position Z1. Here, the ratio of the tilt of the hydrogen chemical concentration and the doping concentration in the interval Z4 to Z1, and the tilt ratio γ obtained by normalizing this tilt ratio, are introduced. The tilt ratio of the hydrogen chemical concentration in the interval Z4 to Z1 is defined as (H1 / aH1) / (Z1-Z4). Similarly, the tilt ratio of the donor concentration in the interval Z4 to Z1 is defined as (D1 / bD1) / (Z1-Z4). Furthermore, using the ratio of the tilt of hydrogen chemical concentration in the interval Z4 to Z1, the tilt ratio γ, obtained by normalizing the tilt ratio of doping concentration, is defined as {(D1 / bD1) / (Z1-Z4)} / {(H1 / aH1) / (Z1-Z4)}. By calculating the previous formula, the normalized tilt ratio γ becomes the simple ratio a / b.

[0145] Figure 10BThis diagram illustrates other definitions of the normalization of the inclination angle of the lower hem 122. In the normalization of the inclination angle of the lower hem 122, for example, an index ε, the same as the index γ, is introduced. Although in Figure 9B In the previous example, position Z6 was different from position Z7, but in this example, position Z6 and position Z7 are set to the same position (Z6 = Z7). Position Z6 is a pre-defined position here. Position Z6 is simply a position where the hydrogen chemical concentration and doping concentration are located on the lower surface 23 side, forming the lower swings 142 and 122, respectively, compared to the second depth position Z2. The hydrogen chemical concentration at position Z6 is set as c × H2, and the doping concentration is set as d × D2. c is the ratio of the hydrogen chemical concentration at position Z6 to the hydrogen chemical concentration H2 at the second depth position Z2. d is the ratio of the doping concentration at position Z6 to the concentration D2 of the second doping concentration peak 121 at the second depth position Z2. Here, the ratio of the slope of the hydrogen chemical concentration and the doping concentration in the interval Z6 to Z2 is introduced, as well as the slope ratio ε obtained by normalizing this slope ratio. The slope ratio of the hydrogen chemical concentration in the interval Z6 to Z2 is defined as (H2 / cH2) / (Z2-Z6). Similarly, the slope ratio of the doping concentration in the interval Z6 to Z2 is defined as (D2 / dD2) / (Z2-Z6). Furthermore, using the slope ratio of the hydrogen chemical concentration in the interval Z6 to Z2, the slope ratio ε, obtained by normalizing the slope ratio of the doping concentration, is defined as {(D2 / dD2) / (Z2-Z6)} / {(H2 / cH2) / (Z2-Z6)}. The normalized slope ratio ε obtained by calculating the previous equation becomes a simple ratio (c / d).

[0146] Regarding the hydrogen chemical concentration peak 131 and the first doping concentration peak 111, the hydrogen chemical concentration distribution and the doping concentration distribution largely exhibit similar shapes. Here, "similar shapes" means that, for example, when the horizontal axis is set to depth and the vertical axis to the common logarithm of concentration, the doping concentration distribution reflects the hydrogen chemical concentration distribution. That is, within a pre-defined interval Z4 to Z1, by ion implantation of hydrogen ions followed by annealing, the doping concentration distribution becomes a distribution that reflects the hydrogen chemical concentration distribution. As an example, if the H1 of the hydrogen chemical concentration peak 131 is 1 × 10⁻⁶... 17 atoms / cm 3 The hydrogen chemical concentration aH1 at position Z4 is 2 × 10⁻⁶. 16 atoms / cm 3 Then a becomes 0.2. On the other hand, if we assume that D1 of the first doping concentration peak 111 is 1×10 16 / cm 3 The doping concentration bD1 at position Z4 is 2 × 10⁻⁶. 15 / cm 3Then b becomes 0.2. Therefore, since the normalized slope ratio γ is a / b, it becomes 1. That is, at the first depth position Z1 near the lower surface 23, the slope ratio a of the hydrogen chemical concentration distribution and the slope ratio b of the doping concentration distribution are approximately the same value, which can be said to be similar shapes.

[0147] On the other hand, regarding the impurity chemical concentration peak 141 and the second doping concentration peak 121, the hydrogen chemical concentration distribution and the doping concentration distribution may not be similar in shape. That is, within the predetermined interval Z6 to Z2, the doping concentration distribution may not reflect the hydrogen chemical concentration distribution. As an example, if the hydrogen chemical concentration H2 of the impurity chemical concentration peak 141 is assumed to be 1 × 10⁻⁶... 16 atoms / cm 3 The chemical concentration of hydrogen (cH2) at position Z6 is 1 × 10⁻⁶. 15 atoms / cm 3 Then c becomes 0.1. On the other hand, if the concentration D2 of the second doping concentration peak 121 is set to 3 × 10⁻⁶, then c becomes 0.1. 14 / cm 3 The doping concentration dD2 at position Z6 is 1.5 × 10⁻⁶. 14 / cm 3 Then d becomes 0.5. Therefore, since the normalized slope ratio ε is c / d, it becomes 0.2. That is, at a second depth position Z2, which is sufficiently deep from the lower surface 23, the slope ratio c of the hydrogen chemical concentration distribution becomes a value 0.2 times smaller than the slope ratio d of the doping concentration distribution, and can be said to exhibit a shape that is not similar to c / d.

[0148] If we compare the normalized slope ratio γ with ε, then when the peak position of the hydrogen chemical concentration distribution is close to the lower surface 23, γ is close to 1, and when the peak position of the hydrogen chemical concentration distribution is sufficiently deep from the lower surface 23, ε can be a value much higher than 1. That is, the normalized slope ratio ε can be greater than the normalized slope ratio γ. Furthermore, the slope ratio ε can be greater than 1.1, greater than 1.5, or greater than 2. Alternatively, it can be greater than 10 or greater than 100.

[0149] It should be noted that there are cases where the actual positions of the hydrogen chemical concentration peak 131 and the impurity chemical concentration peak 141 differ from the actual positions of the first doping concentration peak 111 and the second doping concentration peak 121. In such cases, when the positions of the chemical concentration peaks and the doping concentration peaks are inconsistent, the position of the chemical concentration peak can be set to either the first depth position Z1 or the second depth position Z2. For convenience, the concentration at either the first depth position Z1 or the second depth position Z2 can be set as the peak position. This allows for calculations based on the above definition.

[0150] Figures 11 to 19 This diagram illustrates an example of a method for determining the preferred range of the bulk donor concentration and the donor concentration in the high-concentration region 150. In this example, the bulk donor concentration and the donor concentration are set in a manner that makes the final donor concentration (doping concentration) in the high-concentration region 150 a relatively stable concentration, even if there is a deviation in the bulk donor concentration.

[0151] In this example, the specification value for the bulk donor concentration is set to N. B0 The actual donor concentration is set as N. Bre The specification value for bulk donor concentration refers to the specification value specified by the semiconductor wafer manufacturer. Where there is a range in the specification value, the median value can be used. The resistivity ρ, determined by the concentration of bulk donors such as phosphorus, is given by N = 1 / qμρ, where q is the elementary charge and μ is the electron mobility in the semiconductor substrate 10.

[0152] Set the concentration of hydrogen donors (VOH defects) to N. H Hydrogen donor concentration N H The deviation is so small that it is negligible compared to the deviation in the bulk donor concentration. In this example, the hydrogen donor concentration N... H The deviation is set to 0.

[0153] Set the target value for the final donor concentration to N. F0 Additionally, the actual final donor concentration is set as N. Fre All the concentrations mentioned above are concentrations per unit volume ( / cm³). 3 ).

[0154] The target value N of the final donor concentration F0 It is the specification value N of the donor concentration. B0 Add hydrogen donor concentration N H The value obtained is given by the following formula.

[0155] N F0 =N H +N B0 ...Formula (1)

[0156] On the other hand, the actual donor concentration N Fre This refers to the actual donor concentration N. Bre Add hydrogen donor concentration N H The value obtained is given by the following formula.

[0157] N Fre =N H +N Bre ...Formula (2)

[0158] The parameter β is defined using the following formula.

[0159] β=N Bre / N B0 ...Formula (3)

[0160] The parameter β is the actual bulk donor concentration N. Bre With specification value N B0 The ratio, and shows that the further away from 1 the actual donor concentration N. Bre The greater the deviation from the specification value N B0 The situation.

[0161] The parameter γ is defined using the following formula.

[0162] γ=N Fre / N F0 ...Formula (4)

[0163] The parameter γ is the actual donor concentration N. Fre With the target value N F0 The ratio, and shows that the further away from 1 the actual donor concentration N. Fre The greater the deviation from the target value N F0 In this case, if γ is sufficiently close to 1, it shows that even at actual bulk donor concentrations N... Bre Relative to specification value N B0 When the actual donor concentration N deviates by a factor of β, Fre It also depends almost entirely on the objective value N, without relying on β. F0 The situation is largely the same.

[0164] Here, the resistivity deviation of silicon wafers manufactured by the FZ method, which has a relatively small deviation in bulk donor concentration, is typically as described below.

[0165] • Neutron irradiation of FZ wafers • ±8% (ratio from 0.92 to 1.08)

[0166] • Gas-doped FZ wafers • ±12% (ratio from 0.88 to 1.12)

[0167] Therefore, if γ is above 0.85 and below 1.15, then the final donor concentration N Fre The deviation is to the same extent as the bulk donor concentration of the silicon wafer produced by the FZ method described above. In this specification, the allowable value of γ is set to be 0.85 or higher and 1.15 or lower.

[0168] Actual donor concentration N Fre Subject to the actual body donor concentration N Bre The effect of the bias (β). On the other hand, the hydrogen donor concentration N H If the deviation is related to the donor concentration N Bre Compared to the deviation, it can be considered approximately 0. Therefore, by adjusting the specification value N of the donor concentration...B0 relative to the target value N of the donor concentration F0 It decreases, thus reducing the donor concentration N. Fre This can reduce the proportion of the deviation component.

[0169] The parameter ε' is defined using the following formula.

[0170] N B0 =ε'×N F0 ...Formula (5)

[0171] Where 0 < ε' < 1. The parameter ε' represents the specification value N of the bulk donor concentration. B0 Set as the target value N relative to the donor concentration F0 A parameter that means something like ε'.

[0172] We explore how much smaller ε' is than 1 within a range that is not 0, so that γ is independent of β and sufficiently close to 1.

[0173] The parameter ε is defined using the following formula.

[0174] ε=1 / ε'···Equation (6)

[0175] The following equation is derived from equations (5) and (6).

[0176] N B0 =N F0 / ε···Equation (7)

[0177] Substituting equation (1) into equation (7) yields the following equation.

[0178] N F0 =N H +N F0 / ε, that is, N H =(1-1 / ε)N F0 ...Formula (8)

[0179] Substituting equation (2) into equations (8) and (3) yields the following equation.

[0180] N Fre =(1-1 / ε)N F0 +βN B0 ...Formula (9)

[0181] Substituting equation (9) into equation (7) yields the following equation.

[0182] N Fre =(1-1 / ε)N F0 +(β / ε)N F0

[0183] = (1 - 1 / ε + β / ε)N F0...Formula (10)

[0184] Substituting equation (4) into equation (10) yields the following equation.

[0185] γ=1-1 / ε+β / ε

[0186] =1+(β-1) / ε···Equation (11)

[0187] The following equation is derived from equations (6) and (11).

[0188] γ=1+ε'(β-1)···Equation (12)

[0189] Figure 11 This is a graph showing the relationship between ε' and γ, expressed by equation (12), for each β. As mentioned above, γ represents the actual donor concentration N. Fre Relative to the target value N F0 The ratio, β represents the actual body donor concentration N. Bre Relative to specification value N B0 The ratio. Additionally, the permissible value for γ is above 0.85 and below 1.15.

[0190] For example, the specification value N of the body donor concentration. B0 Let N be the target value of the donor concentration. F0 Below 0.5 times, that is, setting ε' to below 0.5. In this case, even if β is, for example, 1.3, γ becomes below 1.15 and thus falls within the acceptable range. That is, even at the actual bulk donor concentration N Bre Specification value N B0 At a 30% increase, the actual donor concentration N Fre It also becomes the target value N F0 Below 1.15 times. Furthermore, even when β is 0.7, γ is within the acceptable range if ε' is below 0.5. If ε' is close to 0, γ converges towards 1. For example, when β = 2, γ is within the acceptable range if ε' is approximately below 0.2.

[0191] In order to set γ within the above-mentioned allowable range, for example, consider the following ranges A to D as the preferred range for ε'.

[0192] (Scope A)

[0193] ε' is between 0.001 and 0.5. When ε' is 0.5, if β is in the range of 0.7 to 1.3, then γ is within the permissible range. For example, the specification value N for the bulk donor concentration. B0 1×10 14 / cm 3 When ε' is 0.001, the target value N of the donor concentration is...F0 1×10 11 / cm 3 This is equivalent to approximately 46,000 Ωcm.

[0194] (Scope B)

[0195] ε' is between 0.01 and 0.333. When ε' is 0.333, if β is in the range of 0.5 to 1.5, then γ is within the permissible range. For example, the specification value N for the bulk donor concentration. B0 1×10 14 / cm 3 When ε' is 0.01, the target value N of the donor concentration is... F0 1×10 12 / cm 3 This is equivalent to approximately 4600 Ωcm.

[0196] (Scope C)

[0197] ε' is 0.03 or higher and 0.25 or lower. When ε' is 0.25, if β is in the range of approximately 0.4 to 1.6, then γ is within the permissible range. For example, the specification value N for the bulk donor concentration. B0 1×10 14 / cm 3 When ε' is 0.03, the target value N of the donor concentration is... F0 3×10 12 / cm 3 This is equivalent to approximately 1500 Ωcm.

[0198] (Range D)

[0199] ε' is between 0.1 and 0.2. When ε' is 0.2, if β is in the range of approximately 0.2 to 1.8, then γ is within the acceptable range. For example, the specification value N for the bulk donor concentration. B0 1×10 14 / cm 3 When ε' is 0.1, the target value N of the donor concentration is... F0 1×10 13 / cm 3 This is equivalent to approximately 460 Ωcm.

[0200] Furthermore, since a small deviation in resistivity is suitable for practical applications, ε' is preferably 0.1 or less, and more preferably 0.02 or less. In this case, the range E to H, as described below, is considered.

[0201] (Range E)

[0202] ε' is greater than or equal to 0.001 and less than or equal to 0.1. When ε' is 0.1, if β is in the range of approximately 0.05 (not shown) to 3.0, then γ is sufficiently within the permissible range. For example, the specification value N for the bulk donor concentration... B0 1×10 14 / cm 3 When ε' is 0.1, the target value N of the donor concentration is... F0 1×10 13 / cm 3 This is equivalent to approximately 460 Ωcm.

[0203] (Range F)

[0204] ε' is greater than or equal to 0.002 and less than or equal to 0.05. When ε' is 0.05, if β is in the range of approximately 0.01 (not shown) to 5.0, then γ is sufficiently within the permissible range. For example, the specification value N for the bulk donor concentration... B0 1×10 14 / cm 3 When ε' is 0.05, the target value N of the donor concentration is... F0 5×10 12 / cm 3 This is equivalent to approximately 920 Ωcm.

[0205] (Range G)

[0206] ε' is greater than or equal to 0.005 and less than or equal to 0.02. When ε' is 0.02, if β is in the range of approximately 0.01 (not shown) to 10.0, then γ is sufficiently within the permissible range. For example, the specification value N for the bulk donor concentration... B0 1×10 14 / cm 3 When ε' is 0.02, the target value N of the donor concentration is... F0 2×10 12 / cm 3 This is equivalent to approximately 2300 Ωcm.

[0207] (Range H)

[0208] The case where ε' has a range of 0.01 ± 0.002 (20%). When ε' is 0.01, if β is in the range of approximately 0.01 (not shown) to 20.0 (not shown), then γ is sufficiently within the permissible range. For example, the specification value N for the bulk donor concentration. B0 1×10 14 / cm 3 When ε' is 0.01, the target value N of the donor concentration is... F0 1×10 12 / cm3 This is equivalent to approximately 4600 Ωcm.

[0209] As mentioned above, the actual donor concentration N Fre The donor concentration corresponds to the high-concentration region 150. Based on the donor concentration of the high-concentration region 150, which occupies a large area in the semiconductor substrate 10, the withstand voltage of the semiconductor device 100 is approximately determined. Therefore, based on the rated voltage of the semiconductor device 100, the donor concentration N of the high-concentration region 150 is... Fre The preferred range is determined. This is related to the donor concentration N. Fre Accordingly, it can make the donor concentration N Fre Stable body donor concentration N Bre The scope is determined.

[0210] Figure 12 This shows the concentration of donor N in vivo. Bre A diagram illustrating an example of a preferred range. In this example, the donor concentration N at the center Zc in the depth direction of the semiconductor substrate 10 is... Fre ( / cm 3 (9.20245×10) 15 ) / x or more and (9.20245×10 16 Below ) / x. Where x is the rated voltage (V). Donor concentration N Fre ( / cm 3 The doping concentration can be determined by referring to the doping concentration of the drift region in a typical semiconductor substrate formed by the FZ method, but it can also be determined by referring to the doping concentration of the drift region in a semiconductor substrate formed by the MCZ method. Figure 12 In the diagram, the dashed line represents the donor concentration N. Fre ( / cm 3 The upper limit 311 and the lower limit 312 of the preferred range.

[0211] exist Figure 12 In the diagram, the solid line represents the bulk donor concentration N in the range A (ε' is 0.001 or higher and 0.5 or lower). Bre The preferred range is defined by the upper limit 313 and the lower limit 314. Organism donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.5). The donor concentration N Bre The lower limit of 314 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.001. Organism donor concentration N BreThe upper limit 313 and lower limit 314 are as follows. It should be noted that the units for the upper limit 313 and lower limit 314 in each example are ( / cm). 3 As mentioned above, x is the rated voltage (V).

[0212] • Lower limit 314: (9.20245×10 12 ) / x

[0213] • Upper limit 313: (4.60123×10 16 ) / x

[0214] Figure 13 This shows the bulk donor concentration N when ε' is in the range B (above 0.01 and below 0.333). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.333). The donor concentration N is... Bre The lower limit of 314 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.01. Organism donor concentration N Bre The upper limit 313 and the lower limit 314 are as follows.

[0215] • Lower limit 314: (9.20245×10 13 ) / x

[0216] • Maximum value 313: (3.06442×10 16 ) / x

[0217] Figure 14 This shows the bulk donor concentration N when ε' is in the range C (above 0.03 and below 0.25). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.25). The donor concentration N is... Bre The lower limit of 314 is the donor concentration NFre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.03. The donor concentration N is... Bre The upper limit 313 and the lower limit 314 are as follows.

[0218] • Lower limit 314: (2.76074×10 14 ) / x

[0219] • Upper limit 313: (2.30061×10 16 ) / x

[0220] Figure 15 This shows the bulk donor concentration N when ε' is in the range D (above 0.1 and below 0.2). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.2). The donor concentration N is... Bre The lower limit of 314 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.1. The donor concentration N is... Bre The upper limit 313 and the lower limit 314 are as follows.

[0221] • Lower limit 314: (9.20245×10 14 ) / x

[0222] • Upper limit 313: (1.84049×10 16 ) / x

[0223] Figure 16 This shows the bulk donor concentration N when ε' is in the range E (above 0.001 and below 0.1). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.1). The donor concentration N is... Bre The lower limit of 314 is the donor concentration NFre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.001. Organism donor concentration N Bre The upper limit 313 and the lower limit 314 are as follows.

[0224] • Lower limit 314: (9.20245×10 12 ) / x

[0225] • Maximum value 313: (9.20245×10 15 ) / x

[0226] Figure 17 This shows the bulk donor concentration N when ε' is in the range F (above 0.002 and below 0.05). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.05). The donor concentration N is... Bre The lower limit of 314 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.002. The donor concentration N is... Bre The upper limit 313 and the lower limit 314 are as follows.

[0227] • Lower limit 314: (1.84049×10 13 ) / x

[0228] • Upper limit 313: (4.60123×10 15 ) / x

[0229] Figure 18 This shows the bulk donor concentration N when ε' is in the range G (above 0.005 and below 0.02). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.02). The donor concentration N is... BreThe lower limit of 314 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.005. Organism donor concentration N Bre The upper limit 313 and the lower limit 314 are as follows.

[0230] • Lower limit 314: (4.60123×10 13 ) / x

[0231] • Upper limit 313: (1.84049×10 15 ) / x

[0232] Figure 19 This shows the bulk donor concentration N when ε' is in the range H (0.01 ± 0.002). Bre A diagram illustrating an example of the preferred range. It should be noted that the donor concentration N... Fre ( / cm 3 The upper limit 311 and the lower limit 312 of ) are related to Figure 12 The example is the same. Donor concentration N Bre The upper limit of 313 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the upper limit of 311 of ε' by the upper limit of ε' (0.01). The donor concentration N is... Bre The lower limit of 314 is the donor concentration N Fre ( / cm 3 The value is obtained by multiplying the lower limit of 312 (ε') by the lower limit of 0.01. Organism donor concentration N Bre The upper limit 313 and the lower limit 314 are as follows.

[0233] • Lower limit 314: (9.20245×10 13 ) / x

[0234] • Maximum value 313: (9.20245×10 14 ) / x

[0235] It should be noted that the upper limit 313 and lower limit 314 within each range can have a range of ±20%.

[0236] like Figures 12 to 19 As shown, by adjusting the donor concentration N... Bre Let the concentration be between the upper limit 313 and the lower limit 314 in each example, so that the final donor concentration N can be represented. Fre The γ-suppression of the deviation is within the allowable range. It should be noted that the curve for the lower limit of 314 is sometimes smaller than the intrinsic carrier concentration. Here, the intrinsic carrier concentration is 1.45 × 10⁻⁶ at room temperature (e.g., 300 K). 10 / cm 3If the value of the curve at the lower limit of 314 is smaller than the intrinsic carrier concentration, then the lower limit of 314 can be replaced by the intrinsic carrier concentration.

[0237] Figure 20 This is an example of a top view of a semiconductor device 100. Figure 20 The image shows the positions formed by projecting each component onto the upper surface of the semiconductor substrate 10. Figure 20 The image shows only a portion of the components of the semiconductor device 100, with some components omitted.

[0238] Semiconductor device 100 is equipped with Figures 1 to 19 The semiconductor substrate 10 is described herein. The semiconductor substrate 10 has end edges 102 when viewed from above. In this specification, "viewed from above" simply means viewed from the top surface side of the semiconductor substrate 10. In this example, the semiconductor substrate 10 has two sets of end edges 102 that are opposite each other when viewed from above. Figure 20 In this configuration, the X and Y axes are parallel to one of the end edges 102. Additionally, the Z axis is perpendicular to the upper surface of the semiconductor substrate 10.

[0239] An active portion 160 is provided on the semiconductor substrate 10. The active portion 160 is a region between the upper and lower surfaces of the semiconductor substrate 10 where the main current flows along the depth direction when the semiconductor device 100 is operating. Although an emitter is provided above the active portion 160, ... Figure 20 The emitter is omitted.

[0240] The active section 160 is provided with at least one of a transistor section 70 including transistor elements such as IGBTs and a diode section 80 including diode elements such as freewheeling diodes (FWDs). Figure 20 In this example, the transistor section 70 and the diode section 80 are alternately arranged along a predetermined alignment direction (the X-axis direction in this example) on the upper surface of the semiconductor substrate 10. In other examples, only one of the transistor section 70 and the diode section 80 may be provided in the active section 160.

[0241] exist Figure 20 In this specification, the area where the transistor section 70 is arranged is marked with the symbol "I", and the area where the diode section 80 is arranged is marked with the symbol "F". In this specification, the direction perpendicular to the arrangement direction when viewed from above is sometimes referred to as the extension direction (in...). Figure 20 (The middle direction is the Y-axis direction). The transistor section 70 and the diode section 80 may each have a long side in the extending direction. That is, the length of the transistor section 70 in the Y-axis direction is greater than its width in the X-axis direction. Similarly, the length of the diode section 80 in the Y-axis direction is greater than its width in the X-axis direction. The extending directions of the transistor section 70 and the diode section 80 may be the same as the long side direction of each trench section described later.

[0242] The diode portion 80 has an N+ type cathode region in the area contacting the lower surface of the semiconductor substrate 10. In this specification, the area where the cathode region is provided is referred to as the diode portion 80. That is, the diode portion 80 is the area that overlaps with the cathode region when viewed from above. A P+ type collector region may be provided on the lower surface of the semiconductor substrate 10 in the area other than the cathode region. In this specification, the diode portion 80 may sometimes also include an extension region 81 that extends the diode portion 80 along the Y-axis direction to the gate wiring described later. A collector region is provided on the lower surface of the extension region 81.

[0243] The transistor section 70 has a P+ type collector region in the area that contacts the lower surface of the semiconductor substrate 10. In addition, the transistor section 70 has an N-type emitter region, a P-type base region, and a gate structure having a gate conductive portion and a gate insulating film periodically arranged on the upper surface side of the semiconductor substrate 10.

[0244] The semiconductor device 100 may have one or more pads above the semiconductor substrate 10. In this example, the semiconductor device 100 has a gate pad 164. The semiconductor device 100 may also have anode pads, cathode pads, and current sensing pads, etc. Each pad is located near the edge 102. "Near the edge 102" refers to the area between the edge 102 and the emitter when viewed from above. During actual installation of the semiconductor device 100, each pad can be connected to external circuitry via wiring such as cables.

[0245] A gate potential is applied to the gate pad 164. The gate pad 164 is electrically connected to the conductive portion of the gate trench portion of the active portion 160. The semiconductor device 100 includes gate wiring connecting the gate pad 164 to the gate trench portion. Figure 20 In the diagram, a shading line is marked on the gate wiring.

[0246] The gate wiring in this example includes a peripheral gate wiring 130 and an active-side gate wiring 129. The peripheral gate wiring 130 is disposed between the active portion 160 and the edge 102 of the semiconductor substrate 10 in plan view. In this example, the peripheral gate wiring 130 surrounds the active portion 160 in plan view. Alternatively, the area surrounded by the peripheral gate wiring 130 in plan view can also be considered as the active portion 160. Furthermore, the peripheral gate wiring 130 is connected to the gate pad 164. The peripheral gate wiring 130 is disposed above the semiconductor substrate 10. The peripheral gate wiring 130 can be a metal wiring, including aluminum.

[0247] An active-side gate wiring 129 is provided in the active portion 160. By providing the active-side gate wiring 129 in the active portion 160, the deviation in wiring length from the gate pad 164 can be reduced for each region of the semiconductor substrate 10.

[0248] The active-side gate wiring 129 is connected to the gate trench portion of the active portion 160. The active-side gate wiring 129 is disposed above the semiconductor substrate 10. The active-side gate wiring 129 may be wiring formed from semiconductors such as polysilicon doped with impurities.

[0249] The active-side gate wiring 129 can be connected to the outer peripheral gate wiring 130. In this example, the active-side gate wiring 129 is provided to cross the active portion 160 approximately at the center in the Y-axis direction, from one side of the outer peripheral gate wiring 130 to the other side. When the active portion 160 is divided using the active-side gate wiring 129, in each divided region, the transistor portion 70 and the diode portion 80 can be alternately arranged in the X-axis direction.

[0250] Additionally, the semiconductor device 100 may include: a temperature sensing unit (not shown) which is a PN junction diode formed of polysilicon or the like; and a current sensing unit (not shown) which simulates the operation of the transistor unit disposed in the active unit 160.

[0251] In this example, the semiconductor device 100 has an edge termination structure 90 between the active portion 160 and the edge 102. The edge termination structure 90 is disposed between the peripheral gate wiring 130 and the edge 102. The edge termination structure 90 alleviates electric field concentration on the upper surface side of the semiconductor substrate 10. The edge termination structure 90 has multiple guard rings 92. Each guard ring 92 is a P-type region that contacts the upper surface of the semiconductor substrate 10. The guard rings 92 can surround the active portion 160 when viewed from above. The multiple guard rings 92 are arranged at predetermined intervals between the peripheral gate wiring 130 and the edge 102. An outer guard ring 92 can surround an inner guard ring 92. The outer side refers to the side closer to the edge 102, and the inner side refers to the side closer to the peripheral gate wiring 130. By providing multiple guard rings 92, the depletion layer on the upper surface side of the active portion 160 can extend outwards, thereby improving the breakdown voltage of the semiconductor device 100. The edge terminal structure 90 may also include at least one of an annular field plate surrounding the active part 160 and a surface electric field reduction part.

[0252] Figure 21 yes Figure 20An enlarged view of region A is shown. Region A includes the transistor section 70, the diode section 80, and the active-side gate wiring 129. The semiconductor device 100 of this example includes a gate trench section 40, a dummy trench section 30, a well region 11, an emitter region 12, a base region 14, and a contact region 15 disposed inside the upper surface side of the semiconductor substrate 10. The gate trench section 40 and the dummy trench section 30 are examples of trench sections. Furthermore, the semiconductor device 100 of this example includes an emitter 52 and an active-side gate wiring 129 disposed above the upper surface of the semiconductor substrate 10. The emitter 52 and the active-side gate wiring 129 are disposed separately from each other.

[0253] An interlayer insulating film is provided between the emitter 52 and the upper surface of the semiconductor substrate 10, and between the active-side gate wiring 129 and the upper surface of the semiconductor substrate 10, but in Figure 21 The details are omitted. In this example, the interlayer insulating film has contact holes 54 provided in a manner that penetrates the interlayer insulating film. Figure 21 In the middle, the shading of the diagonal lines marks each contact hole 54.

[0254] An emitter 52 is disposed above the gate trench 40, the dummy trench 30, the well region 11, the emitter region 12, the base region 14, and the contact region 15. The emitter 52 contacts the emitter region 12, the contact region 15, and the base region 14 on the upper surface of the semiconductor substrate 10 through a contact hole 54. Furthermore, the emitter 52 is connected to a dummy conductive portion within the dummy trench 30 through a contact hole disposed in the interlayer insulating film. The front end of the emitter 52 in the dummy trench 30 along the Y-axis direction can be connected to a dummy conductive portion of the dummy trench 30.

[0255] The active-side gate wiring 129 is connected to the gate trench portion 40 through a contact hole provided in the interlayer insulating film. The active-side gate wiring 129 can be connected to the gate conductive portion of the gate trench portion 40 at the front end 41 in the Y-axis direction. The active-side gate wiring 129 is not connected to the dummy conductive portion within the dummy trench portion 30.

[0256] The emitter 52 is formed of a material containing metal. Figure 21 The area where the emitter 52 is disposed is shown. For example, at least a portion of the emitter 52 is formed of aluminum or an aluminum-silicon alloy, such as AlSi, AlSiCu, or other metal alloys. The emitter 52 may have a barrier metal formed of titanium or titanium compounds in the lower layer of the area formed of aluminum or the like. Furthermore, a plug formed by embedding tungsten or the like in contact with the barrier metal and the aluminum or the like may be provided within the contact hole.

[0257] The well region 11 is disposed overlapping the active-side gate wiring 129. The well region 11 also extends with a predetermined width in a region that does not overlap with the active-side gate wiring 129. In this example, the well region 11 is separated from the active-side gate wiring 129 at its end relative to the Y-axis direction of the contact hole 54. The well region 11 is a region of a second conductivity type with a higher doping concentration than the base region 14. In this example, the base region 14 is P-type, and the well region 11 is P+ type.

[0258] Both the transistor section 70 and the diode section 80 have multiple trench sections arranged along the arrangement direction. In the transistor section 70 of this example, one or more gate trench sections 40 and one or more dummy trench sections 30 are alternately arranged along the arrangement direction. In the diode section 80 of this example, multiple dummy trench sections 30 are arranged along the arrangement direction. In the diode section 80 of this example, no gate trench section 40 is provided.

[0259] In this example, the gate trench portion 40 may have two straight portions 39 (the trench portion that is straight in the extension direction) extending in an extension direction perpendicular to the arrangement direction, and a front end portion 41 connecting the two straight portions 39. Figure 21 The direction of extension in the middle is the Y-axis direction.

[0260] Preferably, at least a portion of the front end portion 41 is curved when viewed from above. By connecting the ends of the two straight portions 39 in the Y-axis direction through the front end portion 41, the electric field concentration at the ends of the straight portions 39 can be alleviated.

[0261] In the transistor section 70, dummy trench sections 30 are provided between each straight portion 39 of the gate trench section 40. One dummy trench section 30 may be provided between each straight portion 39, or multiple dummy trench sections 30 may be provided. The dummy trench section 30 may have a straight shape extending in the extension direction, or it may have the same straight portion 29 and front end portion 31 as the gate trench section 40. Figure 21 The semiconductor device 100 shown includes both a dummy trench portion 30 with a straight shape and no front end portion 31, and a dummy trench portion 30 with a front end portion 31.

[0262] The diffusion depth of the well region 11 can be deeper than the depths of the gate trench portion 40 and the dummy trench portion 30. The ends of the gate trench portion 40 and the dummy trench portion 30 in the Y-axis direction are provided in the well region 11 when viewed from above. That is, at the ends of each trench portion in the Y-axis direction, the bottom of each trench portion in the depth direction is covered by the well region 11. This helps to alleviate electric field concentration at the bottom of each trench portion.

[0263] Mesa-shaped portions are provided between the trench portions in the arrangement direction. A mesa-shaped portion refers to the area within the semiconductor substrate 10 that is held between the trench portions. For example, the upper end of the mesa-shaped portion is the upper surface of the semiconductor substrate 10. The lower end of the mesa-shaped portion has the same depth as the lower end of the trench portion. In this example, the mesa-shaped portion is provided on the upper surface of the semiconductor substrate 10, extending along the trench in the extension direction (Y-axis direction). In this example, a mesa-shaped portion 60 is provided in the transistor portion 70, and a mesa-shaped portion 61 is provided in the diode portion 80. In this specification, when referred to simply as a mesa-shaped portion, the terms mesa-shaped portion 60 and mesa-shaped portion 61 generally refer to each other.

[0264] A base region 14 is provided on each mesa. The region of the base region 14 exposed on the upper surface of the semiconductor substrate 10 within the mesa, closest to the active-side gate wiring 129, is designated as base region 14-e. Figure 21 Although a base region 14-e is shown at one end of each stage in the extending direction, a base region 14-e is also provided at the other end of each stage. In each stage, the area sandwiched between the base regions 14-e in top view can be provided with at least one of a first conductivity type emitter region 12 and a second conductivity type contact region 15. In this example, the emitter region 12 is N+ type, and the contact region 15 is P+ type. The emitter region 12 and the contact region 15 can be disposed between the base region 14 and the upper surface of the semiconductor substrate 10 in the depth direction.

[0265] The mesa portion 60 of the transistor portion 70 has an emitter region 12 exposed on the upper surface of the semiconductor substrate 10. The emitter region 12 is disposed in contact with the gate trench portion 40. The mesa portion 60 in contact with the gate trench portion 40 may be provided with a contact region 15 exposed on the upper surface of the semiconductor substrate 10.

[0266] Each contact area 15 and each emission area 12 in the platform surface 60 extends from a groove on one side to a groove on the other side in the X-axis direction. As an example, the contact areas 15 and emission areas 12 of the platform surface 60 are alternately arranged along the extension direction of the groove (Y-axis direction).

[0267] In other examples, the contact area 15 and the emission area 12 of the platform 60 can be arranged in a strip shape along the extension direction (Y-axis direction) of the groove. For example, the emission area 12 is provided in the area that contacts the groove, and the contact area 15 is provided in the area sandwiched by the emission area 12.

[0268] The emitter region 12 is not provided on the mesa 61 of the diode section 80. A base region 14 and a contact region 15 may be provided on the upper surface of the mesa 61. A contact region 15 may be provided in contact with each base region 14-e on the upper surface of the mesa 61. A base region 14 may be provided on the upper surface of the mesa 61 within the area sandwiched by the contact region 15. The base region 14 may be disposed over the entire area sandwiched by the contact region 15.

[0269] A contact hole 54 is provided above each stage surface. The contact hole 54 is located in the area sandwiched between the base regions 14-e. In this example, the contact hole 54 is located above the contact region 15, the base region 14, and the emitter region 12. The contact hole 54 is not located in the region corresponding to the base region 14-e and the sink region 11. The contact hole 54 can be located at the center of the stage surface 60 in the arrangement direction (X-axis direction).

[0270] In the diode section 80, an N+ type cathode region 82 is provided in a region adjacent to the lower surface of the semiconductor substrate 10. On the lower surface of the semiconductor substrate 10, in a region where the cathode region 82 is not provided, a P+ type collector region 22 may be provided. Figure 21 In the diagram, a dashed line is used to represent the boundary between the cathode region 82 and the collector region 22.

[0271] The cathode region 82 is disposed separately from the well region 11 in the Y-axis direction. This ensures a sufficient distance between the cathode region 82 and the P-type region (well region 11) with a high doping concentration and deep formation, thereby improving the breakdown voltage. In this example, the end of the cathode region 82 in the Y-axis direction is disposed further away from the well region 11 than the end of the contact hole 54 in the Y-axis direction. In other examples, the end of the cathode region 82 in the Y-axis direction may be disposed between the well region 11 and the contact hole 54.

[0272] Figure 22A It is shown Figure 21 The diagram shows an example of a cross-section bb. The cross-section bb is the XZ plane passing through the emitter region 12 and the cathode region 82. In this example, the semiconductor device 100 has a semiconductor substrate 10, an interlayer insulating film 38, an emitter 52, and a collector 24 in this cross-section. The interlayer insulating film 38 is disposed on the upper surface of the semiconductor substrate 10. The interlayer insulating film 38 is a film comprising at least one layer of an insulating film such as silicate glass with impurities such as boron or phosphorus, a thermally oxidized film, and other insulating films. The interlayer insulating film 38 has a... Figure 21 Contact hole 54 as described in the diagram.

[0273] The emitter 52 is disposed above the interlayer insulating film 38. The emitter 52 contacts the upper surface 21 of the semiconductor substrate 10 through the contact hole 54 of the interlayer insulating film 38. The collector 24 is disposed on the lower surface 23 of the semiconductor substrate 10. The emitter 52 and the collector 24 are formed of a metallic material such as aluminum. In this specification, the direction (Z-axis direction) connecting the emitter 52 and the collector 24 is referred to as the depth direction.

[0274] The semiconductor substrate 10 has an N-type drift region 19. In this example, the drift region 19 is an N-type region extending from the lower end of the accumulation region 16 to the upper end of the buffer zone 20. The drift region 19 in this example has... Figures 1 to 19 The high concentration zone 150 is described in the text. Figure 22A In the diagram, the high-concentration region 150 is shaded by a diagonal line. The high-concentration region 150 can be located in the transistor section 70, the diode section 80, or both. The high-concentration region 150 is the area extending from the upper end of the buffer zone 20 towards the upper surface 21. An impurity chemical concentration peak 141 (see reference) is located at the upper end of the high-concentration region 150. Figure 1 wait).

[0275] The drift region 19 may have an N-type body donor region 18. The body donor region 18 is a region where the doping concentration is the same as the donor concentration of the body donor. The body donor region 18 is disposed in a region that is higher than the high concentration region 150. In this example, the body donor region 18 is disposed in both the transistor section 70 and the diode section 80.

[0276] On the mesa 60 of the transistor section 70, an N+ type emitter region 12 and a P- type base region 14 are sequentially disposed from the upper surface 21 side of the semiconductor substrate 10. A body donor region 18 is disposed below the base region 14. An N+ type accumulation region 16 may be disposed on the mesa 60. The accumulation region 16 is disposed between the base region 14 and the body donor region 18.

[0277] The emitter region 12 is exposed on the upper surface 21 of the semiconductor substrate 10 and is disposed in contact with the gate trench portion 40. The emitter region 12 may contact the trench portions on both sides of the mesa portion 60. The doping concentration of the emitter region 12 is higher than that of the bulk donor region 18.

[0278] The base region 14 is disposed below the launch region 12. In this example, the base region 14 is disposed in contact with the launch region 12. The base region 14 can contact the groove portions on both sides of the platform surface 60.

[0279] Accumulation region 16 is disposed below base region 14. Accumulation region 16 is an N+ type region with a higher doping concentration than drift region 19. The doping concentration of accumulation region 16 can be higher than that of high-concentration region 150. By providing a high-concentration accumulation region 16 between drift region 19 and base region 14, the carrier injection enhancement effect (IE effect) can be improved, and the turn-on voltage can be reduced. Accumulation region 16 can be disposed such that it covers the entire lower surface of base region 14 in each mesa 60.

[0280] A P-type base region 14 is provided in contact with the upper surface 21 of the semiconductor substrate 10 on the mesa 61 of the diode section 80. A bulk donor region 18 is provided below the base region 14. An accumulation region 16 may be provided on the mesa 61 below the base region 14.

[0281] In each transistor section 70 and diode section 80, an N+ type buffer 20 can be provided at a position lower than the high-concentration region 150 on the surface 23 side. Figures 1 to 19 The buffer 20 described herein is the same. The buffer 20 can function as a field cutoff layer to prevent the depletion layer extending from the lower end of the base region 14 from reaching the P+ type collector region 22 and the N+ type cathode region 82.

[0282] In the transistor section 70, a P+ type collector region 22 is provided below the buffer 20. The collector region 22 is... Figures 1 to 19 An example of the lower surface region 201 described herein. The acceptor concentration in the collector region 22 is higher than that in the base region 14. The collector region 22 may contain the same acceptors as the base region 14, or it may contain different acceptors than the base region 14. The acceptors in the collector region 22 are, for example, boron.

[0283] In the diode section 80, an N+ type cathode region 82 is provided below the buffer zone 20. The cathode region 82 is... Figures 1 to 19 An example of the lower surface region 201 described herein. The donor concentration in the cathode region 82 is higher than that in the high-concentration region 150. The donors in the cathode region 82 are, for example, hydrogen or phosphorus. It should be noted that the elements that become donors and acceptors in each region are not limited to the examples described above. The collector region 22 and the cathode region 82 are exposed on the lower surface 23 of the semiconductor substrate 10 and are connected to the collector electrode 24. The collector electrode 24 may contact the entire lower surface 23 of the semiconductor substrate 10. The emitter 52 and the collector electrode 24 may be formed of a metallic material such as aluminum.

[0284] One or more gate trenches 40 and one or more dummy trenches 30 are provided on the upper surface 21 side of the semiconductor substrate 10. Each trench extends from the upper surface 21 of the semiconductor substrate 10, through the base region 14, and reaches the drift region 19. In regions where at least one of the emitter region 12, contact region 15, and accumulation region 16 is provided, each trench also extends through these doped regions and reaches the body donor region 18. The trenches extending through the doped regions are not limited to being formed in the order of forming the trenches after forming the doped regions. The case where doped regions are formed between the trenches after the trenches are formed is also included in the case where the trenches extend through the doped regions.

[0285] As described above, the transistor section 70 is provided with a gate trench section 40 and a dummy trench section 30. The diode section 80 is provided with a dummy trench section 30, but not with a gate trench section 40. In this example, the boundary between the diode section 80 and the transistor section 70 in the X-axis direction is the boundary between the cathode region 82 and the collector region 22.

[0286] The gate trench portion 40 includes a gate trench disposed on the upper surface 21 of the semiconductor substrate 10, a gate insulating film 42, and a gate conductive portion 44. The gate insulating film 42 is disposed covering the inner wall of the gate trench. The gate insulating film 42 may be formed by oxidizing or nitriding the semiconductor on the inner wall of the gate trench. The gate conductive portion 44 is disposed inside the gate trench, at a position further inward than the gate insulating film 42. That is, the gate insulating film 42 insulates the gate conductive portion 44 from the semiconductor substrate 10. The gate conductive portion 44 is formed of a conductive material such as polysilicon.

[0287] The gate conductive portion 44 can be made longer than the base region 14 in the depth direction. The gate trench portion 40 in this cross section is covered by an interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10. The gate conductive portion 44 is electrically connected to the gate wiring. If a predetermined gate voltage is applied to the gate conductive portion 44, a channel formed by an electron inversion layer is formed on the surface layer of the interface in the base region 14 that contacts the gate trench portion 40.

[0288] The dummy trench portion 30 can have the same structure as the gate trench portion 40 in this cross-section. The dummy trench portion 30 has a dummy trench provided on the upper surface 21 of the semiconductor substrate 10, a dummy insulating film 32, and a dummy conductive portion 34. The dummy conductive portion 34 can be connected to an electrode different from the gate pad. For example, the dummy conductive portion 34 can be connected to a dummy pad (not shown) connected to an external circuit different from the gate pad, and controlled differently from the gate conductive portion 44. Alternatively, the dummy conductive portion 34 can be electrically connected to the emitter 52. The dummy insulating film 32 is provided to cover the inner wall of the dummy trench. The dummy conductive portion 34 is provided inside the dummy trench and is located further inward than the dummy insulating film 32. The dummy insulating film 32 insulates the dummy conductive portion 34 from the semiconductor substrate 10. The dummy conductive portion 34 can be formed of the same material as the gate conductive portion 44. For example, the dummy conductive portion 34 is formed of a conductive material such as polysilicon. The dummy conductive portion 34 may have the same length as the gate conductive portion 44 in the depth direction.

[0289] In this example, the gate trench portion 40 and the dummy trench portion 30 are covered by an interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10. It should be noted that the bottom of the dummy trench portion 30 and the gate trench portion 40 can be a downwardly convex curved surface (curved in cross-section).

[0290] Semiconductor substrate 10 has a common feature with Figures 1 to 19 In any example described, the same impurity chemical concentration C I Hydrogen chemical concentration C H and doping concentration D d The distribution of doping concentration in the drift region 19 is thus suppressed by providing a high concentration region 150, according to the semiconductor device 100 of this example.

[0291] Figure 22B It is shown Figure 22A The doping concentration D at the dd line d The distribution example is shown in the figure. The dd line is a line parallel to the Z-axis passing through collector region 22 and mesa 60. In this example, the distribution of doping concentration Dd from collector region 22 to doping concentration peak 121 is shown. Figure 2 The doping concentration D shown d The distribution is the same. In this example, the doping concentration D... d Concentration peaks are present in the accumulation region 16, base region 14, and emitter region 12, respectively. In this example, the semiconductor substrate 10 has a bulk donor region 18 between the accumulation region 16 and the doping concentration peak 121. The bulk donor region 18 can contact the accumulation region 16. That is, at the boundary between the bulk donor region 18 and the accumulation region 16, the doping concentration D... d From the donor concentration D b The concentration increases continuously up to the peak of the accumulation zone 16.

[0292] Figure 23 It is shown Figure 21 Figures for other examples of the bb cross section. In the semiconductor device 100 of this example, the high concentration region 150 is positioned throughout the entire drift region 19, which is consistent with... Figure 22A The examples differ. Other structures can be similar to... Figure 22A The examples are the same.

[0293] In this example, the high-concentration region 150 can be positioned from the upper end of the buffer zone 20 up to the position contacting the accumulation region 16. The high-concentration region 150 can also extend into the interior of the accumulation region 16. In this case, the second doping concentration peak 121 can be positioned within the accumulation region 16. If the semiconductor device 100 does not have an accumulation region 16, the high-concentration region 150 can be positioned up to the position contacting the base region 14. According to this example, doping concentration deviation can be suppressed throughout the entire drift region 19.

[0294] While the present invention has been described above using embodiments, its technical scope is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or alterations can be made to the above embodiments. As can be seen from the claims, such modifications or alterations can also be included within the technical scope of the present invention.

[0295] It should be noted that the execution order of actions, processes, steps, and stages in the apparatus, system, program, and method shown in the claims, specification, and drawings can be implemented in any order unless specifically stated as "earlier than" or "before," and unless the results of previous processes are used in subsequent processes. Even if the flow of actions in the claims, specification, and drawings is described using terms such as "firstly" or "next" for convenience, this does not mean that they must be implemented in this order.

Claims

1. A semiconductor device, characterized in that, have: A semiconductor substrate having an upper surface and a lower surface, and containing a bulk donor; A buffer of the first conductivity type is disposed on the lower surface side of the semiconductor substrate and contains hydrogen donors, and the doping concentration distribution in the depth direction of the semiconductor substrate has a single first doping concentration peak. A high-concentration region of a first conductivity type is disposed between the buffer zone and the upper surface of the semiconductor substrate, and contains hydrogen donors, wherein the donor concentration is higher than the bulk donor concentration; A lower surface region of a first conductivity type or a second conductivity type is disposed between the buffer zone and the lower surface of the semiconductor substrate, and the doping concentration is higher than that of the high concentration region; as well as Impurity chemical concentration peaks, which are disposed on the upper surface side of the semiconductor substrate. The high-concentration region is set from the first doping concentration peak in the buffer zone to the impurity chemical concentration peak.

2. The semiconductor device according to claim 1, characterized in that, The first doping concentration peak in the buffer is the concentration peak of hydrogen donors.

3. The semiconductor device according to claim 1, characterized in that, The first doping concentration peak in the buffer is the concentration peak of N-type dopants other than hydrogen donors.

4. The semiconductor device according to claim 1, characterized in that, The impurity chemical concentration at the upper edge of the impurity chemical concentration peak decreases from the apex toward the upper surface, and the impurity chemical concentration at the lower edge of the impurity chemical concentration peak decreases from the apex toward the lower surface. The impurity chemical concentration at the upper edge of the impurity chemical concentration peak decreases more sharply than the impurity chemical concentration at the lower edge of the impurity chemical concentration peak.

5. The semiconductor device according to claim 4, characterized in that, The semiconductor device also includes: The hydrogen chemical concentration peak is located at the same depth as the first doping concentration peak in the buffer zone; and The second doping concentration peak is located at the same depth as the impurity chemical concentration peak. The impurity chemical concentration peak is the hydrogen chemical concentration peak. Each concentration peak exhibits a downward swing in concentration as it increases from the lower surface of the semiconductor substrate toward the upper surface. The value obtained by normalizing the slope of the lower edge of the second doping concentration peak using the slope of the lower edge of the impurity chemical concentration peak is less than the value obtained by normalizing the slope of the lower edge of the first doping concentration peak using the slope of the lower edge of the hydrogen chemical concentration peak.

6. The semiconductor device according to any one of claims 1 to 5, characterized in that, The high-concentration region has a length in the depth direction of the semiconductor substrate that is more than 50% of the thickness of the semiconductor substrate.

7. The semiconductor device according to any one of claims 1 to 5, characterized in that, The high-concentration region has a length of more than 70 μm in the depth direction of the semiconductor substrate.

8. The semiconductor device according to any one of claims 1 to 5, characterized in that, The donor concentration in the high-concentration region is more than twice the bulk donor concentration.

9. The semiconductor device according to claim 8, characterized in that, The donor concentration in the high-concentration region is more than 5 times the bulk donor concentration.

10. The semiconductor device according to any one of claims 1 to 5, characterized in that, With the rated voltage of the semiconductor device set to xV, the bulk donor concentration is 9.20245 × 10⁻⁶. 12 / x or higher and 4.60123×10 16 Below / x, the unit for the volume donor concentration is atoms / cm. 3 .

11. The semiconductor device according to claim 10, characterized in that, The concentration of the organ donor was 9.20245 × 10⁻⁶. 14 / x or higher and 1.84049×10 16 / x and below.

12. The semiconductor device according to claim 10, characterized in that, The donor concentration at the center of the depth direction of the semiconductor substrate is 9.20245 × 10⁻⁶. 15 / x or higher and 9.20245×10 16 Below / x, the unit of donor concentration at the center of the depth direction of the semiconductor substrate is / cm. 3 .

13. The semiconductor device according to any one of claims 1 to 5, characterized in that, The semiconductor device further includes an accumulation region disposed on the upper surface side of the semiconductor substrate, and the accumulation region has a higher doping concentration than the high-concentration region. The high-concentration zone is set up until it contacts the accumulation zone.

14. A method for manufacturing a semiconductor device, characterized in that, include: In the first implantation stage, charged particles are implanted from the lower surface of a semiconductor substrate having an upper and lower surface and containing a volume donor to a second position on the upper surface side of the semiconductor substrate, and hydrogen ions are implanted to a first position so that the hydrogen chemical concentration distribution has a single peak in a region closer to the lower surface side than the second position; and In the first annealing stage, the semiconductor substrate is annealed to form a high-concentration region with a higher donor concentration than the bulk donor concentration, such that the hydrogen ions implanted at the first position diffuse from the first position to the second position.

15. The method for manufacturing a semiconductor device according to claim 14, characterized in that, The method for manufacturing the semiconductor device further includes a grinding stage, in which the lower surface side of the semiconductor substrate is ground after the first annealing stage to remove the region including the first location.

16. The method for manufacturing a semiconductor device according to claim 15, characterized in that, The method for manufacturing the semiconductor device further includes a second implantation stage, after the grinding stage, where an N-type dopant is implanted from the lower surface of the semiconductor substrate to a position closer to the lower surface than the second position.

17. The method for manufacturing a semiconductor device according to claim 15, characterized in that, The method of manufacturing the semiconductor device further includes a second implantation stage, after the grinding stage, where hydrogen ions are implanted from the lower surface of the semiconductor substrate to a position further from the lower surface than the second position.

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