Semiconductor device

Abstract

A semiconductor device includes a semiconductor substrate having a top surface and a bottom surface, and a bulk donor of a first conductivity type distributed throughout the semiconductor substrate; a high concentration region of the first conductivity type including a central position in a depth direction of the semiconductor substrate, and having a higher donor concentration than a doping concentration of the bulk donor; and an upper surface side oxygen reduction region disposed in contact with the top surface of the semiconductor substrate inside the semiconductor substrate, and having a smaller oxygen chemical concentration closer to the top surface of the semiconductor substrate. The oxygen chemical concentration distribution can have a maximum value region in which the oxygen chemical concentration is 50% or more of a maximum value, a first peak of an impurity chemical concentration can be disposed at an end portion in the depth direction of the high concentration region, the first peak can be disposed within the maximum value region, or can be disposed at a position closer to the top surface of the semiconductor substrate than the maximum value region.

Description

Technical Field

[0001] This invention relates to a semiconductor device. Background Technology

[0002] Previously, it was known that hydrogen donors could be generated from crystal defects caused by proton irradiation and the introduced protons during heat treatment of semiconductor wafers. (For example, see paragraph 0061 of Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-153183 Summary of the Invention

[0006] Technical issues

[0007] Semiconductor devices preferably have small deviations in donor concentration.

[0008] Technical means

[0009] To address the aforementioned problems, in one aspect of the present invention, a semiconductor device is provided comprising a semiconductor substrate having an upper surface and a lower surface, and on which bulk donors of a first conductivity type are uniformly distributed. The semiconductor device may include a high-concentration region of the first conductivity type, which is a region including a central location in the depth direction of the semiconductor substrate, wherein the donor concentration is higher than the doping concentration of the bulk donors. The semiconductor device may include an upper-surface oxygen-reducing region, which is disposed within the semiconductor substrate and in contact with the upper surface of the semiconductor substrate, and the oxygen concentration decreases the closer it is to the upper surface of the semiconductor substrate.

[0010] The oxidation chemical concentration distribution along the depth direction of the semiconductor substrate can have a maximum value region, which is a region including the location where the oxidation chemical concentration reaches its maximum value and where the oxidation chemical concentration is 50% or more of the maximum value. A first peak of impurity chemical concentration can be positioned at the depth end of the high concentration region. The first peak can be positioned within the maximum value region, or it can be positioned further towards the upper surface of the semiconductor substrate than the maximum value region.

[0011] The depth-direction distribution of impurity chemical concentration can have a lower side where the impurity chemical concentration decreases from the first peak toward the lower surface, and an upper side where the impurity chemical concentration decreases more sharply from the first peak toward the upper surface than the lower side.

[0012] The high-concentration region can be set from the first peak to the lower surface of the semiconductor substrate.

[0013] The oxidative concentration distribution can have an oxygen concentration peak where the oxidative concentration reaches a maximum value.

[0014] The impurity chemical concentration distribution may have a second peak of hydrogen chemical concentration positioned between the first peak and the lower surface.

[0015] The semiconductor device may include a lower surface-side oxygen reduction region, which is positioned further down the surface than the upper surface-side oxygen reduction region, and the closer to the lower surface of the semiconductor substrate, the lower the oxygen chemical concentration. A second peak of hydrogen chemical concentration may be located within the lower surface-side oxygen reduction region.

[0016] The second peak of hydrogen chemical concentration can be configured in the maximum value region.

[0017] The semiconductor device may include a drift region of a first conductivity type disposed on the semiconductor substrate. The semiconductor device may also include a buffer zone disposed between the drift region and the lower surface, having a higher doping concentration than the drift region. A second peak of hydrogen chemical concentration may be disposed within the buffer zone.

[0018] The recombination center concentration distribution along the depth direction of the semiconductor substrate can have a recombination concentration peak. This peak can be located in a region where the chemical concentration is above 70% of its maximum value.

[0019] The first peak can be configured in the region where the oxidative concentration is above 70% of the maximum value.

[0020] The donor can be phosphorus or antimony.

[0021] The semiconductor substrate can have bulk acceptors of the second conductivity type distributed throughout.

[0022] The acceptor can be boron.

[0023] The chemical concentration of impurities can be the chemical concentration of hydrogen.

[0024] The semiconductor device may have one or more guard rings in contact with the upper surface of the semiconductor substrate and having a second conductivity type. The semiconductor device may have a channel stop portion of either a first or second conductivity type, disposed further outward than the outermost guard ring, in contact with the upper surface of the semiconductor substrate, and having a higher doping concentration than the bulk donor. The channel stop portion may contain hydrogen.

[0025] Hydrogen can be distributed from the lower surface of the semiconductor substrate to the channel cutoff portion.

[0026] A peak for hydrogen chemical concentration can be set at the cutoff point of the channel.

[0027] 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

[0028] Figure 1 This is a cross-sectional view showing an example of a semiconductor device 100.

[0029] Figure 2 Show Figure 1 The oxidative concentration C at the location indicated by line AA OX Chemical concentration of impurities C I Hydrogen chemical concentration C H and VOH defect concentration N VOH Distribution example along the depth direction.

[0030] Figure 3 Show Figure 1 The oxidative concentration C at the position indicated by line AA OX Chemical concentration of impurities C I Hydrogen chemical concentration C H and VOH defect concentration N VOH Other distribution examples in the depth direction.

[0031] Figure 4 This is a graph showing an example of the change in the chemical concentration distribution of the MCZ substrate before and after oxygen annealing.

[0032] Figure 5 This is a graph showing an example of the change in the chemical concentration distribution of the FZ substrate before and after oxygen annealing.

[0033] Figure 6 This indicates the concentration of the complexation center N. r With oxidative concentration C OX The distribution of examples is shown in the figure.

[0034] Figure 7 This is a diagram illustrating the location of the third peak, 403.

[0035] Figure 8 This is an example of a top view of a semiconductor device 100.

[0036] Figure 9 yes Figure 8 An enlarged view of region A in the image.

[0037] Figure 10 It is shown Figure 9 A diagram of an example of the bb section.

[0038] Figure 11 It is shown Figure 8 A diagram of an example of the cc section.

[0039] Figure 12 Show Figure 11 The carrier concentration N at the dd line shownC Phosphorus chemical concentration C P VOH defect concentration N VOH and the chemical concentration of impurities C I Distribution example.

[0040] Figure 13A It is shown Figure 8 Figures of other examples of the cc section.

[0041] Figure 13B It is shown Figure 8 Figures of other examples of the cc section.

[0042] Figure 13C It is shown Figure 8 Figures of other examples of the cc section.

[0043] Figure 14 It is shown Figure 8 Figures of other examples of the cc section.

[0044] Figure 15 It is shown Figure 8 Figures of other examples of the cc section.

[0045] Figure 16 It is shown Figure 8 Figures of other examples of the cc section.

[0046] Figure 17 It is shown Figure 8 Figures of other examples of the cc section.

[0047] Figure 18A It is shown Figure 8 Figures of other examples of the cc section.

[0048] Figure 18B It is shown Figure 8 Figures of other examples of the cc section.

[0049] Figure 18C It is shown Figure 8 Figures of other examples of the cc section.

[0050] Figure 19 It is shown Figure 8 Figures of other examples of the cc section.

[0051] Figure 20 It is shown Figure 8 Figures of other examples of the cc section.

[0052] Figure 21A It is shown Figure 8 Figures of other examples of the cc section.

[0053] Figure 21B It is shown Figure 8 Figures of other examples of the cc section.

[0054] Figure 22 It is shown in Figure 20 A diagram illustrating an example of the method for forming the high-concentration region 460 as described in the text.

[0055] Figure 23 It is shown in Figure 21A A diagram illustrating an example of the method for forming the high-concentration region 460 as described in the text.

[0056] Symbol Explanation

[0057] 10. Semiconductor substrate; 11. Well region; 12. Emitter region; 14. Base region; 15. Contact region; 16. Accumulation region; 18. Bulk doped 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 portion, 41 • Front end portion, 42 • Gate insulating film, 44 • Gate conductive portion, 52 • Emitter, 54 • Contact hole, 60, 61 • Mesa portion, 70 • Transistor portion, 80 • Diode portion, 81 • Extended region, 82 • Cathode region, 90 • Edge termination structure portion, 91 • Region, 92 • Guard ring, 94 • Field plate, 100 • Semiconductor device, 102 • Edge, 106 • Through Region, 112···Gate pad, 130···Outer perimeter gate wiring, 131···Active-side gate wiring, 160···Active section, 174···Channel cutoff section, 202···Second high concentration region, 203···Third high concentration region, 313···Plateau, 314···Peak, 318···Phosphorus concentration peak, 323···Plateau, 350···Shielding component, 401···First peak, 402···Second peak, 403···Third peak, 404···Fourth peak, 405··· • Oxygen concentration peak, 406 • Complex center peak, 407 • Donor concentration peak, 408 • Peak, 411, 412, 413, 414 • Upper side sloping, 421, 422, 423, 424 • Lower side sloping, 425 • Fifth peak, 426 • Sixth peak, 435, 436 • Upper side sloping, 445, 446 • Lower side sloping, 450 • Upper surface oxygen reduction region, 452 • Maximum value region, 454 • Lower surface oxygen reduction region, 460 • High concentration region Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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 height direction 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.

[0061] 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, a 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. In this specification, the term "upper surface side of the semiconductor substrate" refers to the region along the depth direction of the semiconductor substrate extending from the center to the upper surface. The term "lower surface side of the semiconductor substrate" refers to the region along the depth direction of the semiconductor substrate extending from the center to the lower surface.

[0062] 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%.

[0063] In this specification, the conductivity type of doped regions is described as P-type or N-type. In this specification, "impurity" sometimes specifically refers to either an N-type donor or a P-type acceptor, and is sometimes referred to as a dopant. In this specification, doping refers to introducing donors or acceptors into a semiconductor substrate to create a semiconductor representing an N-type conductivity type or a semiconductor representing a P-type conductivity type.

[0064] 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, taking the donor concentration as the concentration of positive ions and the acceptor concentration as the concentration of negative ions. For example, if the donor concentration is set to N... D And set the acceptor concentration to N A Then the actual net doping concentration at any position becomes N. D -N A .

[0065] 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, which are formed by the combination of vacancies (V), oxygen (O), and hydrogen (H) in semiconductors, act as electron donors.

[0066] When referred to as P+ or N+ type in this specification, it means that the doping concentration is higher than that of P- or N- type. When referred to as P- or N- type, it means that the doping concentration is lower than that of P- or N- type. Furthermore, when referred to as P++ or N++ type in this specification, it means that the doping concentration is higher than that of P+ or N+ type.

[0067] In this specification, chemical concentration refers to the atomic density of impurities measured independently of the state of electrical activation. Chemical concentration (atomic density) can be measured using, for example, secondary ion mass spectrometry (SIMS). The net doping concentration can be measured using voltage-capacitance measurement (CV). Alternatively, the carrier concentration measured using extended resistance measurement (SR) can be used as the net doping concentration. The carrier concentration obtained by CV or SR can be considered 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 used as the donor concentration. Similarly, in the P-type region, the carrier concentration in this region can also be used as the acceptor concentration.

[0068] 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.

[0069] The carrier concentration obtained 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 value in the crystalline state. This decrease in carrier mobility is caused by the disorder (disorder) of the crystal structure due to lattice defects, etc., which leads to carrier dispersion.

[0070] The donor or acceptor concentration calculated from the carrier concentration measured by CV or SR methods 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 about 99% of their chemical concentration. On the other hand, in silicon semiconductors, the donor concentration of hydrogen (which acts as a donor) is about 0.1% to 10% of the chemical concentration of hydrogen.

[0071] 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.

[0072] 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 The arrangement of transistor and diode elements within the electrodes and semiconductor substrate 10 is omitted.

[0073] N-type body donors are distributed throughout the semiconductor substrate 10 in this example. Body donors are formed by dopants that are substantially uniformly contained within the blank during the fabrication of the substrate that forms the basis of the semiconductor substrate 10. In this example, the body donors are elements other than hydrogen. Although the dopants for the body donors are, for example, group V or group VI elements, such as 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 in the P-type regions. The semiconductor substrate 10 can be a wafer cut from a semiconductor blank or a chip monolithically formed from wafers. The semiconductor blank can be manufactured using any of the following methods: Czochralski (CZ) method, magnetic Czochralski (MCZ) method, or floating zone melting (FZ) method.

[0074] The chemical concentration of the substrate manufactured using the MCZ method is, for example, 1 × 10⁻⁶. 17 ~7×10 17 atoms / cm 3 The chemical concentration of the substrate manufactured using the FZ method, for example, is 1 × 10⁻⁶. 15 ~5×10 16 atoms / cm 3The 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. In semiconductor substrates doped with group V or VI dopants such as phosphorus, the bulk donor concentration can be 1 × 10⁻⁶. 11 / cm 3 Above and 3×10 13 / cm 3 The bulk donor concentration of semiconductor substrates doped with group V or group VI dopants is preferably 1 × 10⁻⁶. 12 / cm 3 Above and 1×10 13 / cm 3 The following applies. Alternatively, the semiconductor substrate 10 can be an undoped substrate that substantially does not contain host dopants such as phosphorus. In this case, the bulk donor concentration (N) of the undoped substrate is... B0 ) is, for example, 1×10 10 / cm 3 Above and 5×10 12 / cm 3 The following is the bulk donor concentration (N) of the undoped substrate. B0 The preferred value is 1×10 11 / cm 3 The above. Bulk donor concentration (N) of the undoped substrate. B0 The preferred value is 5×10 12 / cm 3 the following.

[0075] 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.

[0076] In a semiconductor substrate 10, a beam of charged particles is injected from the lower surface 23 toward a predetermined depth position Z1. The main surface of the semiconductor substrate 10 to which the charged particle beam is injected may not be limited to the lower surface 23, but may also be the upper surface 21. In this specification, the distance in the Z-axis direction from the upper surface 21 is sometimes referred to as the depth position. In this specification, the central position in the depth direction of the semiconductor substrate 10 is defined as the depth position Zc. The depth position Z1 is the position at a distance Z1 from the upper surface 21 in the Z-axis direction. The depth position Z1 is disposed on the side of the upper surface 21 of the semiconductor substrate 10 (the region between the depth position Zc and the upper surface 21). Injecting a beam of charged particles into the depth position means that the average distance (also referred to as the range) that the charged particles travel through the interior of the semiconductor substrate 10 is Z1. The charged particles are accelerated with an acceleration energy corresponding to the predetermined depth position Z1 and introduced into the interior of the semiconductor substrate 10.

[0077] The region through which charged particles pass through the interior of the semiconductor substrate 10 is designated as the passage region 106. Figure 1 In this example, the region 106 extends from the lower surface 23 of the semiconductor substrate 10 to a depth Z1. Charged particles are particles capable of forming lattice defects in the region 106. These charged particles are, for example, hydrogen ions, helium ions, or electrons. Charged particles can be implanted onto the entire surface of the semiconductor substrate 10 in the XY plane, or only into a portion of the region.

[0078] The semiconductor substrate 10 has a first peak 401 of charged particle concentration at depth Z1. In this example, the charged particle is hydrogen. That is, the semiconductor substrate 10 in this example has a first peak 401 of hydrogen chemical concentration in the depth direction at depth Z1. The first peak 401 can also be a peak in the helium chemical concentration distribution.

[0079] In the passage region 106 where charged particles pass through the semiconductor substrate 10, 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. Although they can broadly include donors and / or acceptors, 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 numerous lattice defects from the injection of 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] Additionally, oxygen is present throughout the semiconductor substrate 10. This oxygen is intentionally or unintentionally introduced during the fabrication of the semiconductor blank. Furthermore, hydrogen is present in at least a portion of the region passing through region 106. This hydrogen can be intentionally injected into the interior of the semiconductor substrate 10.

[0081] In this example, hydrogen ions are injected from the lower surface 23 to a depth position Z2. The hydrogen ions in this example are protons. The main surface of the semiconductor substrate 10 where hydrogen ions are injected may not be limited to the lower surface 23, but may also be the upper surface 21. In this example, the semiconductor substrate 10 has a second peak 402 of hydrogen chemical concentration at depth position Z2. Figure 1In the diagram, the first peak 401 and the second peak 402 are schematically shown using dashed lines. The depth position Z2 can be included within the passage region 106. In this example, the depth position Z2 is located on the lower surface 23 side of the semiconductor substrate 10 (the region between the depth position Zc and the lower surface 23). It should be noted that hydrogen injected into the depth position Z1 can diffuse into the passage region 106, or hydrogen can be introduced into the passage region 106 using other methods. In these cases, hydrogen ions may not be injected into the depth position Z2.

[0082] After the through region 106 is formed on the semiconductor substrate 10 and hydrogen ions are implanted into the semiconductor substrate 10, hydrogen (H), vacancies (V), and oxygen (O) combine inside the semiconductor substrate 10 to form VOH defects. Furthermore, by performing heat treatment on the semiconductor substrate 10 (sometimes referred to as annealing in this specification), hydrogen diffusion is facilitated, promoting the formation of VOH defects. Additionally, by performing heat treatment after forming the through region 106, hydrogen can combine with vacancies, thus suppressing hydrogen from escaping to the outside of the semiconductor substrate 10.

[0083] VOH defects function as donors of electrons. In this specification, VOH defects are sometimes referred to simply as hydrogen donors. In the semiconductor substrate 10 of this example, hydrogen donors are formed in region 106. The doping concentration of the hydrogen donors at each location is lower than the chemical concentration of hydrogen at each location. Regarding the chemical concentration of hydrogen, the ratio of the chemical concentration of hydrogen to the doping concentration of the hydrogen donors (VOH defects) can be a value of 0.1% to 30% (i.e., 0.001 or more and 0.3 or less). In this example, the ratio of the chemical concentration of hydrogen to the doping concentration of the hydrogen donors (VOH defects) is 1% to 5%. It should be noted that, unless otherwise specified, in this specification, VOH defects having a distribution similar to the chemical concentration distribution of hydrogen, and VOH defects having a distribution similar to the vacancy defects in region 106, are both referred to as hydrogen donors, or hydrogen as a donor.

[0084] By forming hydrogen donors in the passage region 106 of the semiconductor substrate 10, the donor concentration in the passage region 106 can be made higher than the doping concentration of the bulk donor (sometimes simply referred to as 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 the rated voltage or withstand voltage. In this regard, according to... Figure 1The semiconductor device 100 shown can adjust the donor concentration of the semiconductor substrate 10 by controlling the dosage of charged particles. Therefore, the semiconductor device 100 can be manufactured using a semiconductor substrate with a bulk donor concentration that does not correspond to the characteristics of the device. Although the deviation of the bulk donor concentration during the manufacture of the semiconductor substrate 10 is relatively large, the dosage of charged particles 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, and the donor concentration in the transmission region can also be controlled with high precision.

[0085] Based on the upper surface 21, the depth position Z1 can be configured within a range of less than half the thickness of the semiconductor substrate 10, or within a range of less than one-quarter of the thickness of the semiconductor substrate 10. Based on the lower surface 23, the depth position Z2 can be configured within a range of less than half the thickness of the semiconductor substrate 10, or within a range of less than one-quarter of the thickness of the semiconductor substrate 10. However, the depth positions Z1 and Z2 are not limited to these ranges.

[0086] The semiconductor substrate 10 has an upper surface oxygen reduction region 450. The upper surface oxygen reduction region 450 is a region inside the semiconductor substrate 10 and is in contact with the upper surface 21 of the semiconductor substrate 10. Furthermore, the upper surface oxygen reduction region 450 is a region where the oxide concentration decreases as the depth approaches the upper surface 21. The upper surface oxygen reduction region 450 can be a region where the oxide concentration decreases over a length of at least 3% of the substrate thickness of the semiconductor substrate 10, or a region where the oxide concentration decreases over a length of at least 5% of the substrate thickness, or a region where the oxide concentration decreases over a length of at least 10% of the substrate thickness. The substrate thickness refers to the thickness of the semiconductor substrate 10 in the depth direction.

[0087] In semiconductor blanks or wafers cut from blanks, the oxygen content is generally uniform across the entire substrate. However, the oxygen concentration varies considerably between substrates. If the oxygen concentration varies, the concentration of VOH defects formed by hydrogen implantation is also prone to deviation.

[0088] In this example, the semiconductor substrate 10 is annealed at a predetermined annealing temperature and for a predetermined annealing time. The semiconductor substrate 10 can be annealed in the state of a wafer obtained from a blank, or in the state of a chip obtained from a wafer. Annealing is preferably performed before the implantation of a charged particle beam. In this specification, this annealing before the implantation of a charged particle beam is sometimes referred to as oxygen annealing.

[0089] During oxygen annealing, the surface of the semiconductor substrate 10 may be exposed in an oxygen-containing atmosphere or may have an oxide film formed thereon. The oxygen annealing time is a time long enough for oxygen at a concentration corresponding to the solid solution limit of the oxygen annealing temperature to be introduced into the substrate. The oxygen annealing time can be more than 1 hour, more than 2 hours, or more than 10 hours. The oxygen solid solution limit refers to the maximum concentration of oxygen that can dissolve into the substrate, and varies depending on the oxygen annealing temperature. The oxygen annealing temperature is, for example, 1000°C or higher, but is not limited to this. The oxygen annealing temperature can be set such that the oxygen solid solution limit is much higher than the chemical concentration of the oxide layer of the semiconductor substrate 10 before oxygen annealing.

[0090] By performing oxygen annealing for a certain or longer time, oxygen at a chemical concentration approximately consistent with the solid solution limit is introduced into the semiconductor substrate 10. Therefore, by managing the oxygen annealing temperature in a manner that corresponds to the solid solution limit and the desired oxidation concentration, the oxidation concentration of the semiconductor substrate 10 can be controlled. Furthermore, since the oxygen annealing temperature is relatively easy to manage, the deviation in oxidation concentration between substrates can also be reduced.

[0091] During the process of removing the semiconductor substrate 10 from the oxygen atmosphere and allowing the temperature to return from the oxygen annealing temperature to room temperature, oxygen near the surface of the semiconductor substrate 10 diffuses outward from the substrate (referred to as outward diffusion in this specification). Outward diffusion is more likely to occur closer to the surface of the semiconductor substrate 10. Therefore, an upper surface-side oxygen reduction region 450 is formed on the semiconductor substrate 10. It should be noted that a lower surface-side oxygen reduction region is also formed in the area contacting the lower surface 23 of the semiconductor substrate 10. However, in cases where the lower surface 23 side of the semiconductor substrate 10 has been ground, there may be instances where the lower surface-side oxygen reduction region remains unresidual.

[0092] This process reduces the deviation in the chemical concentration of oxides in the semiconductor substrate 10. Therefore, the concentration of VOH defects and the donor concentration of the semiconductor substrate 10 are easily controlled.

[0093] Figure 2 Show Figure 1 The oxidative concentration C at the position indicated by line AA OX Chemical concentration of impurities C I Hydrogen chemical concentration C H VOH defect concentration N VOH and net doping concentration N D Distribution example along the depth direction. Figure 2 The distributions after oxygen annealing and hydrogen annealing following hydrogen implantation are shown.

[0094] Figure 2 The horizontal axis shows the depth position 21 from the upper surface, and the vertical axis represents the concentration per unit volume in logarithmic form. Figure 2 The chemical concentration in the sample is measured using methods such as the SIMS method. Figure 2 In the diagram, dashed lines are used to represent the volume donor concentration N. B Donor concentration N B It can be uniform throughout the entire semiconductor substrate 10. As an example, the semiconductor substrate 10 in this example is an MCZ substrate.

[0095] Oxidative concentration C OX The distribution has an oxygen reduction region 450 on the upper surface side. As described above, oxygen annealing is performed to cause oxygen near the upper surface 21 to diffuse outward. In this example, after oxygen annealing, the lower surface 23 side of the semiconductor substrate 10 is ground. Therefore, no lower surface side oxygen reduction region is provided on the lower surface 23 of the semiconductor substrate 10.

[0096] In the oxygen reduction region 450 on the upper surface side, the rate of decrease in chemical concentration relative to the depth direction per unit distance becomes greater the closer it gets to the upper surface 21. That is, the closer to the upper surface 21, the more rapidly the chemical concentration can decrease.

[0097] Oxidative concentration C OX The distribution has a maximum region of 452. The maximum region of 452 is located in the depth direction, encompassing the chemical concentration C. OX Become the maximum value C OX_max Location and oxidative concentration C OX For the predetermined boundary concentration C b The above area. Boundary concentration C b It can be the maximum value C OX_max The oxygen reduction area can be 50%, 70% or more, 80% or more, 90% or more, or even 100% or more. In this example, the oxygen reduction area 450 on the upper surface is positioned between the maximum value area 452 and the upper surface 21. The depth position of the boundary between the oxygen reduction area 450 on the upper surface and the maximum value area 452 is set to Zb. Furthermore, in this example, the maximum value area 452 extends from depth position Zb to the lower surface 23.

[0098] Maximum value C OX_max It can be 3×10 15 atoms / cm 3 Above and 2×10 18 atoms / cm 3 Below. Maximum value C OX_max It can be 1×10 16 atoms / cm 3 The above can also be 1×10 17 atoms / cm 3 That's all. Maximum value C OX_max It can be 1×10 18atoms / cm 3 The following can also be 1×10 17 atoms / cm 3 the following.

[0099] Impurity chemical concentration C I The first peak at depth Z1 is 401. In this example, the impurity is hydrogen. The impurity chemical concentration C... I The distribution has impurity chemical concentration C I The decrease in the upper side swing 411 from the first peak 401 towards the upper surface 21, and the impurity chemical concentration C I The lower side swings down from the first peak 401 toward the lower surface 23, decreasing in size. (As in...) Figure 1 As explained, the impurity (hydrogen in this example) is injected from the lower surface 23 to depth position Z1. Therefore, the impurity chemical concentration C of the upper lower helix 411 is... I The impurity chemical concentration C of the lower hem 421 can be compared. I A more drastic reduction. The lower edge 421 can be set from the first peak 401 to the lower surface 23. Impurity chemical concentration C I This can be the chemical concentration of hydrogen injected from the lower surface 23 of the semiconductor substrate 10 to depth position Z1. The first peak 401 can be positioned in the oxygen reduction region 450 on the upper surface side. The depth position Z1 of the first peak 401 can be positioned further from the upper surface 21 than the depth position Zc. The depth position Z1 of the first peak 401 can be positioned further from the depth position Zc than the depth position Zc. b The position is further up on the upper surface 21 side.

[0100] In this example, the hydrogen chemical concentration C H A second peak 402 is located at a depth position Z2 between the first peak 401 and the lower surface 23. In this example, the second peak 402 is located in the maximum value region 452. The chemical concentration of the second peak 402 can be greater than that of the first peak 401. This facilitates hydrogen diffusion into the passage region 106. The value of the second peak 402 can be more than twice, more than five times, more than ten times, or more than one hundred times that of the first peak 401.

[0101] Hydrogen chemical concentration C H The distribution has hydrogen chemical concentration C H The upper side swing 412 decreases from the second peak 402 towards the upper surface 21, and the hydrogen chemical concentration C H The lower side swings down from the second peak 402 toward the lower surface 23, decreasing in size. (As in...) Figure 1 As explained, hydrogen ions are injected from the lower surface 23 to depth position Z2. Therefore, the hydrogen chemical concentration C at the upper side lower helix 412 is... H The hydrogen chemical concentration C can be compared to that of the lower hem 422.H A more rapid reduction. Specifically, by heat-treating the semiconductor substrate 10, hydrogen diffuses from the second peak 402 to the first peak 401, thus the upper sloping edge 412 can have a gentler portion than the lower sloping edge 422. At various positions between the first peak 401 and the second peak 402, a bulk donor concentration of N can be present. B Hydrogen concentrations can be more than 10 times higher than chemical concentrations, or even more than 100 times higher, or even more than 200 times higher.

[0102] In this example, the VOH defect concentration N VOH The distribution at depth Z1 exhibits a third peak, 403. Numerous vacancy defects caused by charged particle beam injection form at depth Z1. Therefore, VOH defects readily form at depth Z1. Furthermore, in this example, the VOH defect concentration N... VOH The distribution at depth Z2 exhibits a fourth peak, 404. Numerous vacancy defects caused by hydrogen ion implantation form at depth Z2. Therefore, VOH defects are readily formed at depth Z2.

[0103] VOH defect concentration N VOH The distribution has VOH defect concentration N VOH The decrease in the upper side swing 413 from the third peak 403 towards the upper surface 21, and the VOH defect concentration N VOH The lower side sloping downwards from the third peak 403 toward the lower surface 23 decreases. The VOH defect concentration N of the upper side sloping downwards 413... VOH The VOH defect concentration N can be compared with the lower hem 423. VOH A more dramatic reduction.

[0104] VOH defect concentration N VOH The distribution has VOH defect concentration N VOH The decrease in the upper side swing 414 from the fourth peak 404 towards the upper surface 21, and the VOH defect concentration N VOH The lower side swing 424 decreases from the fourth peak 404 towards the lower surface 23. The VOH defect concentration N of the upper side swing 414... VOH The VOH defect concentration N can be compared to the lower hem 424. VOH A more dramatic reduction.

[0105] In this example, the net doping concentration N D It has the ability to increase the concentration of donor N in the body B With VOH defect concentration N VOH The concentration obtained by addition. Due to the concentration of the bulk donor N B The net doping concentration N remains approximately constant throughout the semiconductor substrate 10, therefore... D The shape of the distribution is related to the VOH defect concentration N VOHThe shapes of their distributions are similar.

[0106] In this example, the net doping concentration N D The distribution at depth Z1 exhibits a fifth peak at 425. Additionally, the net doping concentration N in this example... D The distribution at depth Z2 has a sixth peak at 426. Net doping concentration N D The distribution has a net doping concentration N D The decrease in the upper side swing 435 from the fifth peak 425 towards the upper surface 21, and the net doping concentration N D The lower side swing 445 decreases from the fifth peak 425 towards the lower surface 23. The net doping concentration N of the upper side swing 435 is... D It can be compared to the net doping concentration N of the lower side 445. D A more dramatic reduction.

[0107] Net doping concentration N D The distribution has a net doping concentration N D The decrease in the upper side swing 436 from the sixth peak 426 towards the upper surface 21, and the net doping concentration N D The lower side swing 446 decreases from the sixth peak 426 towards the lower surface 23. The net doping concentration N of the upper side swing 436 is... D It can be compared to the net doping concentration N of the lower side 446. D A more dramatic reduction.

[0108] It should be noted that the positions of the vertices of the first peak 401, the third peak 403, and the fifth peak 425 do not need to be strictly consistent. Similarly, the positions of the vertices of the second peak 402, the fourth peak 404, and the sixth peak 426 also do not need to be strictly consistent. As long as the vertex of another peak is located within half the full width of one peak, the two peaks can be set in the same position.

[0109] Because VOH defects are formed in region 106, the donor concentration in region 106 is higher than the bulk donor concentration N. B In this specification, VOH defects with donor concentrations higher than the bulk donor concentration N will be included. B The high-concentration region is referred to as the high-concentration region 460. The high-concentration region 460 includes a depth position Zc of the semiconductor substrate 10 and is provided throughout a predetermined length in the depth direction. The length of the high-concentration region 460 in the depth direction can be more than 50%, 60%, 70%, 80%, or 90% of the substrate thickness. In this example, the high-concentration region 460 extends from the first peak 401 to the lower surface 23.

[0110] Additionally, a high-concentration region 460 may be formed above the first peak 401. The first peak 401 has a predetermined half-peak width in the depth direction. Therefore, vacancy defects are also formed at a position higher than the first peak 401, and a high-concentration region 460 is formed thereas. The width of the high-concentration region 460 above the first peak 401 in the depth direction is smaller than the width of the high-concentration region 460 below the first peak 401 in the depth direction.

[0111] The high concentration region 460 can be the VOH defect concentration N. VOH Specific donor concentration N B High regions. Therefore, even with a high in vivo donor concentration of N... B Even with deviations, the VOH defect concentration N can be controlled with high precision. VOH To suppress donor concentration deviation. VOH defect concentration N VOH It can be the concentration of the donor N. B It can be more than 2 times, or more than 5 times, or even more than 10 times.

[0112] like Figure 2 As shown, a first peak 401 is disposed at the end of the high concentration region 460 on the upper surface 21 side. The first peak 401 can be disposed within the maximum value region 452, or it can be disposed at a position further on the upper surface 21 than the maximum value region 452. In this example, the first peak 401 is disposed within the oxygen reduction region 450 on the upper surface side. As a result, the high concentration region 460 can be formed over a wider range in the depth direction. Therefore, the donor concentration of the semiconductor substrate 10 can be controlled with high precision over a wider range.

[0113] The first peak, 401, can be configured at an oxidation concentration of C. OX The maximum value C OX_max Areas with an oxidation concentration of C of 10% or more can be configured. OX The maximum value C OX_max Areas exceeding 30% can be configured at an oxidation concentration of C. OX The maximum value C OX_max Areas with an oxidation concentration of C of more than 50% can also be configured. OX The maximum value C OX_max In areas where over 70% of the oxygen concentration is present, it can also be configured at chemical concentrations of C. OX The maximum value C OX_max More than 90% of the area. If the chemical concentration C OX If the concentration of oxidation C is small, then the chemical concentration C is small. OX The variation in positional offset relative to depth increases. This is achieved through the determination of the chemical concentration C... OXBy configuring a first peak 401 in a region above a predetermined value, variations in the size of the third peak 403 can be suppressed when the depth position of the first peak 401 shifts. Therefore, variations in the characteristics of the semiconductor device 100 can be suppressed.

[0114] Figure 3 Show Figure 1 The oxidative concentration C at the position indicated by line AA OX Chemical concentration of impurities C I Hydrogen chemical concentration C H VOH defect concentration N VOH and net doping concentration N D Other distribution examples in the depth direction. Figure 3 The distributions after heat treatment are shown. In this example, the oxidizing concentration C... OX and Figure 2 The examples differ. Other concentration distributions are different. Figure 2 The example is the same. In this example, the semiconductor substrate 10 is, for example, an FZ substrate.

[0115] In this example, the oxidative concentration C OX At depth Zp, there is a maximum value C. OX_max The oxygen concentration peak is 405. Maximum value C. OX_max The range can be with Figure 2 The maximum value C OX_max The range is the same. The oxidative concentration C in this example is... OX The distribution of Figure 2 In addition to the maximum value region 452 and the upper surface oxygen reduction region 450 shown, there is also a lower surface oxygen reduction region 454. The lower surface oxygen reduction region 454 is in contact with the lower surface 23, and the closer it is to the lower surface 23, the higher the oxidative concentration C. OX The area with the greatest reduction. The maximum value area 452 is located between the oxygen reduction area 450 on the upper surface side and the oxygen reduction area 454 on the lower surface side.

[0116] The lower surface oxygen reduction region 454 can be compared to the upper surface oxygen reduction region 450, with a higher oxidative concentration C. OX A region that reduces oxygen more slowly. The lower surface-side oxygen reduction region 454 can be longer in the depth direction than the upper surface-side oxygen reduction region 450. Therefore, compared to the case where the upper surface-side oxygen reduction region 450 is longer, the oxidation concentration C in the semiconductor substrate 10 can be reduced more. OX The variation is relatively small. The length in the depth direction of the oxygen reduction region 454 on the lower surface side can be more than 30%, more than 40%, or more than 50% of the substrate thickness. In this example, the second peak 402 and the fourth peak 404 are disposed in the oxygen reduction region 454 on the lower surface side.

[0117] In this example, the first peak 401 can also be configured in the oxygen reduction region 450 on the upper surface side. The depth position Z1 of the first peak 401 can be configured further to the upper surface 21 than the depth position Zc. p The position is further up on the upper surface 21. The depth position Z1 of the first peak 401 can be configured to be higher than the depth position Z. b The position is further up on the upper surface 21. The depth position Z1 of the first peak 401 can be configured at depth position Z. p With depth position Z b between.

[0118] Figure 4 This is a graph illustrating an example of the change in the chemical concentration distribution of the MCZ substrate before and after oxygen annealing. Before oxygen annealing, the chemical concentration C of the MCZ substrate... MCZ Relatively high. Oxidative concentration C MCZ For example, the solution limit is higher than the oxygen annealing temperature. If such a substrate is oxygen annealed, oxygen in the substrate diffuses outward, increasing the chemical concentration C of the substrate. OX It becomes approximately equal to the solid solution limit. This is because outward diffusion is promoted near the upper surface 21 of the semiconductor substrate 10, thus increasing the oxidation concentration C. OX The concentration decreases as it approaches the upper surface 21. It should be noted that in this example, the semiconductor substrate 10 is ground on the lower surface 23 side after oxygen annealing. Therefore, on the lower surface 23 side, the oxidation concentration C... OX Roughly constant.

[0119] Figure 5 This is a graph illustrating an example of the change in the oxide concentration distribution of an FZ substrate before and after oxygen annealing. Before oxygen annealing, the oxide concentration C of the FZ substrate... FZ Relatively low. Oxidative concentration C FZ For example, the solid solution limit below the oxygen annealing temperature. If such a substrate is subjected to oxygen annealing, oxygen is introduced into the substrate, and in the region with a small distance from the upper surface 21 of the semiconductor substrate 10, the chemical concentration C of the oxide in the substrate is low. OX It becomes approximately equal to the solid solution limit. Since oxygen is difficult to introduce in regions far from the upper surface 21, the chemical concentration C increases with increasing distance from the upper surface 21. OX It decreases slowly. Furthermore, due to the promotion of outward diffusion near the upper surface 21 of the semiconductor substrate 10, the oxidation concentration C... OX The value decreases as it approaches the upper surface 21. Therefore, sometimes the chemical concentration C... OX It exhibits an oxygen concentration peak of 405. It should be noted that in this example, the semiconductor substrate 10 undergoes grinding on the lower surface 23 side after oxygen annealing. Therefore, on the lower surface 23 side, the oxidation concentration C... OXIt does not have a peak and descends slowly and monotonously toward the lower surface 23.

[0120] exist Figure 4 and Figure 5 In any of the examples shown, even if the original oxidation concentration is different, the oxidation concentration inside the semiconductor substrate 10 can be controlled by means of oxygen annealing temperature, etc. Therefore, the deviation of VOH defect concentration can be reduced.

[0121] Figure 6 This indicates the concentration of the complexation center N. r With oxidative concentration C OX The distribution of examples. Chemical concentration C. OX and Figure 2 or Figure 3 The example shown is the same. In Figure 6 In the middle, magnified view Figure 3 The oxidative concentration C shown OX The distribution is near the upper surface 21.

[0122] In the semiconductor device 100, recombination centers such as vacancy defects are formed to adjust the lifetime of charge carriers. For example, recombination centers can be formed by injecting charged particles such as hydrogen, helium, or electron beams into the semiconductor substrate 10. In this example, the recombination center concentration N... r At depth position Z r The semiconductor substrate 10 exhibits a recombination center peak 406. Regarding the vacancy concentration, calculation methods are known, for example, using well-known computational software and / or tools (e.g., see http: / / www.srim.org / ). Alternatively, the location of the minimum value of the resistivity distribution in the depth direction of the semiconductor substrate 10 can also be used as the location of the recombination center peak 406.

[0123] The recombination center peak 406 can be formed on the upper surface 21 side of the semiconductor substrate 10 at an oxidation concentration of C. OX The region accounts for over 70%. The complex center peak 406 can combine with hydrogen to become a VOH defect. Therefore, if the oxidative concentration C OX Large deviations in concentration lead to inaccurate recombination center concentrations, making it difficult to precisely adjust carrier lifetimes. In this example, because the recombination center peak 406 is positioned at an oxidation concentration of C... OX The concentration of recombination centers is relatively stable in this region, making it easy to control the concentration and allowing for precise adjustment of carrier lifetimes. The recombination center peak 406 can form in areas with a chemical concentration of C... OX The maximum value C OX_max It can be configured in more than 80% of the area, or in more than 90% of the area.

[0124] Depth position Z rThis location can be the same as the depth position Z1 to which the injected charged particle beam is located. That is, the carrier lifetime can be adjusted by injecting a charged particle beam into depth position Z1. Furthermore, depth position Z... r It could also be a location near depth Z1 but closer to the injection surface of the charged particle beam (lower surface 23 in this example) than depth Z1. When the charged particles injected into depth Z1 are hydrogen ions, recombination centers near depth Z1 become VOH defects by combining with hydrogen. Therefore, the concentration of recombination centers at depth Z1 is lower. r Displacement towards the hydrogen ion injection surface (lower surface 23 in this example). Depth position Z1 and depth position Z r The distance can be less than 5μm, less than 3μm, or less than 1μm.

[0125] In other examples, the depth position Z r It can also be a position different from depth position Z1. In this case, in addition to injecting a charged particle beam into depth position Z1, a beam is also injected into depth position Z. r Inject a beam of charged particles. Towards depth position Z. r The injection of a charged particle beam can be performed after hydrogen annealing, which is used to diffuse the hydrogen injected to depth position Z2.

[0126] Figure 7 This is a diagram illustrating the location of the third peak, 403. Figure 7 In this context, variations of the position of the third peak 403 are represented as third peaks 403-1, 403-2, and 403-3. An arbitrary third peak 403 is provided on the semiconductor substrate 10. The third peak 403-1 is positioned between the oxygen concentration peak 405 and the boundary position Zb. The boundary position Zb is the oxygen chemical concentration C. OX The boundary position between the maximum concentration region 452 and the oxygen reduction region 450 on the upper surface side. Therefore, the high concentration region 460 (refer to...) can be... Figure 2 , Figure 3 The formation is relatively long and can suppress the deviation of the value of the third peak 403.

[0127] In other examples, the third peak 403-2 is positioned in the oxygen reduction region 450 on the upper surface side. In this case, the high concentration region 460 can be formed longer. In other examples, the third peak 403-3 is positioned between the oxygen concentration peak 405 and the depth position Zc. In this case, the third peak 403-3 can be positioned at the oxygen concentration C. OX The variation is relatively gradual in the region. The third peak, 403-3, can be configured in the maximum value region of 452.

[0128] Figure 8 This is an example of a top view of a semiconductor device 100. Figure 8The image shows the positions of the components projected onto the upper surface of the semiconductor substrate 10. Figure 8 The image shows only a portion of the components of the semiconductor device 100, with some components omitted.

[0129] Semiconductor device 100 is equipped with Figures 1 to 7 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 1 In this configuration, the X and Y axes are parallel to either end edge 102. Additionally, the Z axis is perpendicular to the upper surface of the semiconductor substrate 10.

[0130] 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 operated. An emitter is provided above the active portion 160, but... Figure 8 The emitter is omitted.

[0131] 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 8 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.

[0132] exist Figure 8 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 the context of the diagram). Figure 8 (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.

[0133] 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.

[0134] The transistor section 70 has a P+ type collector region in the region 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.

[0135] Semiconductor device 100 may have one or more pads above semiconductor substrate 10. In this example, semiconductor device 100 has a gate pad 112. Semiconductor device 100 may 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. When actually mounting semiconductor device 100, each pad can be connected to external circuitry via wiring such as cables.

[0136] A gate potential is applied to the gate pad 112. The gate pad 112 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 112 to the gate trench portion. Figure 8 In the diagram, a shading line is marked on the gate wiring.

[0137] The gate wiring in this example includes a peripheral gate wiring 130 and an active-side gate wiring 131. 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 112. The peripheral gate wiring 130 is disposed above the semiconductor substrate 10. The peripheral gate wiring 130 can be a metal wiring, including aluminum.

[0138] An active-side gate wiring 131 is provided in the active portion 160. By providing the active-side gate wiring 131 in the active portion 160, the deviation in wiring length from the gate pad 112 can be reduced for each region of the semiconductor substrate 10.

[0139] The active-side gate wiring 131 is connected to the gate trench portion of the active portion 160. The active-side gate wiring 131 is disposed above the semiconductor substrate 10. The active-side gate wiring 131 can be a wiring formed from a semiconductor such as polysilicon doped with impurities.

[0140] The active-side gate wiring 131 can be connected to the outer peripheral gate wiring 130. In this example, the active-side gate wiring 131 is provided such that it crosses 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 of the outer peripheral gate wiring 130, and extends along the X-axis direction. When the active portion 160 is divided using the active-side gate wiring 131, in each divided region, the transistor portion 70 and the diode portion 80 can be alternately arranged along the X-axis direction.

[0141] 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.

[0142] 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 a field plate arranged in an annular shape surrounding the active part 160 and a surface electric field reducing element.

[0143] Figure 9 yes Figure 8An enlarged view of region A is shown. Region A includes the transistor section 70, the diode section 80, and the active-side gate wiring 131. 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 131 disposed above the upper surface of the semiconductor substrate 10. The emitter 52 and the active-side gate wiring 131 are disposed separately from each other.

[0144] 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 131 and the upper surface of the semiconductor substrate 10, but in Figure 9 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 9 In the middle, the shading of the diagonal lines marks each contact hole 54.

[0145] 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. Furthermore, the emitter 52 is connected to a dummy conductive portion within the dummy trench 30 through a contact hole provided 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 the dummy conductive portion of the dummy trench 30.

[0146] The active-side gate wiring 131 is connected to the gate trench portion 40 through a contact hole provided in the interlayer insulating film. The active-side gate wiring 131 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 131 is not connected to the dummy conductive portion within the dummy trench portion 30.

[0147] The emitter 52 is formed of a material containing metal. Figure 9 The area where the emitter 52 is provided 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.

[0148] The well region 11 is disposed overlapping with the active-side gate wiring 131. The well region 11 is also disposed with a predetermined width in a region that does not overlap with the active-side gate wiring 131. In this example, the well region 11 is disposed separately from the end-to-end active-side gate wiring 131 in the Y-axis direction of the contact hole 54. The well region 11 is a region of the 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.

[0149] 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.

[0150] 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 9 The direction of extension in the middle is the Y-axis direction.

[0151] 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.

[0152] 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 9 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.

[0153] 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.

[0154] Mesa-shaped portions are provided between the trench portions in the arrangement direction. A mesa-shaped portion refers to a region 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 is at the same depth as the lower end of the trench portion. In this example, the mesa-shaped portion is located on the upper surface of the semiconductor substrate 10 and extends along the trench portion in the extending 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 are used interchangeably.

[0155] 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 that is closest to the active-side gate wiring 131 is designated as base region 14-e. Figure 9 Although a base region 14-e is shown disposed at one end of each stage in the extending direction, a base region 14-e is also disposed at the other end of each stage. In each stage, the area sandwiched by the base region 14-e in top view may 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 may be disposed between the base region 14 and the upper surface of the semiconductor substrate 10 in the depth direction.

[0156] 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.

[0157] 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).

[0158] In other examples, the contact area 15 and the emission area 12 of the platform 60 can be configured as strips 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 that is held by the emission area 12.

[0159] 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 on the upper surface of the mesa 61 in contact with each base region 14-e in the area sandwiched by the base regions 14-e. A base region 14 may be provided on the upper surface of the mesa 61 in 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.

[0160] A contact hole 54 is provided above each stage surface. The contact hole 54 is located in the area held by the base region 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).

[0161] 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 9 In the diagram, a dashed line is used to represent the boundary between the cathode region 82 and the collector region 22.

[0162] 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.

[0163] Figure 10 It is shown Figure 9 A diagram illustrating an example of a bb cross-section. The bb cross-section 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. A layer of [missing information - likely a specific type of insulating film] is disposed on the interlayer insulating film 38. Figure 9 Contact hole 54 as described in the text.

[0164] 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.

[0165] The semiconductor substrate 10 has an N-type body doped region 18. The body doped region 18 is a region where the doping concentration of the body doped region 18 is the same as the donor concentration of the body donor. The body doped region 18 is disposed in each transistor section 70 and each diode section 80.

[0166] 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 bulk doped 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 bulk doped region 18.

[0167] 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 doped region 18.

[0168] 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.

[0169] Accumulation region 16 is disposed below base region 14. Accumulation region 16 is an N+ type region with a higher doping concentration than the bulk doped region 18. By providing a high-concentration accumulation region 16 between the bulk doped region 18 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.

[0170] 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 doped 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.

[0171] In each transistor section 70 and diode section 80, an N+ type buffer 20 may be provided at a position lower than the bulk doped region 18 and the high concentration region 460 on the surface 23 side. The doping concentration of the buffer 20 is higher than that of the bulk doped region 18. The buffer 20 has one or more donor concentration peaks with a higher donor concentration than that of the bulk doped region 18. The multiple donor concentration peaks are arranged at different positions in the depth direction of the semiconductor substrate 10. The donor concentration peaks of the buffer 20 may be, for example, concentration peaks of hydrogen (proton) or phosphorus. The buffer 20 may include a second peak 402 of hydrogen chemical concentration (see reference). Figure 2 (etc.). Buffer 20 can function as a field cutoff layer to prevent the depletion layer extending from the lower end of base region 14 from reaching the P+ type collector region 22 and the N+ type cathode region 82.

[0172] In the transistor section 70, a P+ type collector region 22 is provided below the buffer 20. 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. The acceptors in the collector region 22 are, for example, boron.

[0173] In the diode section 80, an N+ type cathode region 82 is provided below the buffer zone 20. The donor concentration of the cathode region 82 is higher than that of the bulk doped region 18. The donors of 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 can contact the entire lower surface 23 of the semiconductor substrate 10. The emitter 52 and the collector electrode 24 can be formed of a metallic material such as aluminum.

[0174] One or more gate trench portions 40 and one or more dummy trench portions 30 are provided on the upper surface 21 side of the semiconductor substrate 10. Each trench portion extends from the upper surface 21 of the semiconductor substrate 10, penetrates the base region 14, and reaches the body doped region 18. In regions where at least one of the emitter region 12, contact region 15, and accumulation region 16 is provided, each trench portion also penetrates these doped regions and reaches the body doped region 18. The trench portion penetrating the doped region is not limited to being manufactured in the order of forming the trench portion after forming the doped region. The step of forming the doped region between the trench portions after forming the trench portion is also included in the step of trench portion penetrating the doped region.

[0175] 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.

[0176] 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.

[0177] The gate conductive portion 44 may be 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.

[0178] 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.

[0179] 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).

[0180] Semiconductor substrate 10 has a common feature with Figures 1 to 6 The same oxidative concentration C is used in any of the examples described. OX Chemical concentration of impurities C I Hydrogen chemical concentration C H and VOH defect concentration N VOH The distribution of. In Figure 10In the diagram, the first peak 401 is represented by an × symbol, and the high-concentration region 460 is marked with a shading. The buffer zone 20, cathode region 82, and collector region 22 can also be included within the high-concentration region 460, but... Figure 10 The slashes are omitted. The high-concentration region 460 can be set from the first peak 401 to the lower surface 23.

[0181] As described above, the high-concentration region 460 includes VOH defects. The bulk doped region 18 and the high-concentration region 460 are sometimes collectively referred to as the drift region 19. The drift region 19 may be a region where the depletion layer expands and supports more than half of the applied voltage when a voltage is applied to the semiconductor device 100.

[0182] Figure 11 It is shown Figure 8 A diagram illustrating an example of the cc section. The cc section is the XZ plane passing through the edge terminal structure 90, transistor section 70, and diode section 80. The structures of transistor section 70 and diode section 80 are similar to those in... Figure 9 and Figure 10 The transistor section 70 and diode section 80 described herein are the same. Figure 11 The structure of the gate trench portion 40 and the dummy trench portion 30 is simplified and shown in the figure.

[0183] In the semiconductor substrate 10, a well region 11 is provided between the edge termination structure portion 90 and the transistor portion 70. The well region 11 is a P+ type region that contacts the upper surface 21 of the semiconductor substrate 10. The well region 11 can be provided at a position deeper than the lower ends of the gate trench portion 40 and the dummy trench portion 30. A portion of the gate trench portion 40 and the dummy trench portion 30 can be disposed inside the well region 11.

[0184] An interlayer insulating film 38 covering the well region 11 may be disposed on the upper surface 21 of the semiconductor substrate 10. Electrodes and wirings such as an emitter 52 and a peripheral gate wiring 130 are disposed above the interlayer insulating film 38. The emitter 52 extends from above the active portion 160 to above the well region 11. The emitter 52 can be connected to the well region 11 through a contact hole provided in the interlayer insulating film 38.

[0185] The outer peripheral gate wiring 130 is disposed between the emitter 52 and the edge termination structure 90. Although the emitter 52 and the outer peripheral gate wiring 130 are disposed separately from each other, in Figure 11 In this diagram, the gap between the emitter 52 and the peripheral gate wiring 130 is omitted. The peripheral gate wiring 130 is electrically insulated from the well region 11 by the interlayer insulating film 38.

[0186] The edge terminal structure 90 is provided with multiple guard rings 92, multiple second high-concentration regions 202, multiple field plates 94, and a channel cutoff portion 174. Additionally, a first peak 401 and a high-concentration region 460 are also provided in at least a portion of the edge terminal structure 90. The high-concentration region 460 may be located below the guard rings 92. The first peak 401 and the high-concentration region 460 of the edge terminal structure 90 may be continuously provided with the first peak 401 and the high-concentration region 460 of the transistor section 70 and the diode section 80. The first peak 401 and the high-concentration region 460 may be provided throughout the entire X-axis direction of the edge terminal structure 90.

[0187] In this example, the first peak 401 is located further below the second high-concentration region 202 (i.e., deeper than the second high-concentration region 202 when viewed from the upper surface 21). The first peak 401 can be located deeper than the lower end of the guard ring 92. That is, the first peak 401 can be located between the lower end of the guard ring 92 and the lower surface 23 of the semiconductor substrate 10. The first peak 401 can be located deeper than the lower end of the well region 11. The first peak 401 can be located deeper than the lower end of the trench portion.

[0188] Although Figure 11 The high-concentration region 460 shown does not contact the guard ring 92, but it may contact the lower end of the guard ring 92. The high-concentration region 460 may extend between the two guard rings 92. The high-concentration region 460 may or may not contact the trap region 11. The high-concentration region 460 may or may not contact the trench portion. The high-concentration region 460 may be located below the second high-concentration region 202.

[0189] The high-concentration region 460 may contact the sink region 11. The high-concentration region 460 may contact the trench portion. The high-concentration region 460 may not contact any of the emission region 12, the base region 14, and the accumulation region 16. In other examples, the high-concentration region 460 may contact the accumulation region 16. The high-concentration region 460 may contact the base region 14. The high-concentration region 460 may or may not contact the channel cutoff portion 174.

[0190] Throughout the edge terminal structure 90, the length of the high concentration region 460 in the depth direction can be the same or different. Similarly, the length of the high concentration region 460 in the depth direction can be the same or different between the edge terminal structure 90 and the active part 160.

[0191] In the edge terminal structure 90, a current collector region 22 may be provided in the area contacting the lower surface 23. Each guard ring 92 may be provided such that it surrounds the active portion 160 on the upper surface 21. The plurality of guard rings 92 may have the function of extending the depletion layer generated in the active portion 160 to the outside of the semiconductor substrate 10. As a result, electric field concentration inside the semiconductor substrate 10 can be prevented, and the withstand voltage of the semiconductor device 100 can be improved.

[0192] In this example, the guard ring 92 is a P+ type semiconductor region formed near the upper surface 21 by ion implantation. The guard ring 92 can be formed by selectively implanting a P-type dopant such as boron from the upper surface 21 of the semiconductor substrate 10 and then performing heat treatment. The depth of the bottom of the guard ring 92 can be deeper than the depth of the bottom of the gate trench 40 and the dummy trench 30. The depth of the bottom of the guard ring 92 can be the same as or different from the depth of the bottom of the well region 11.

[0193] The upper surface of the guard ring 92 is covered by the interlayer insulating film 38. The field plate 94 is formed of a metal such as aluminum or a conductive material such as polycrystalline silicon. The field plate 94 can be formed of an aluminum-silicon alloy, such as AlSi or AlSiCu. The field plate 94 can be formed of the same material as the outer peripheral gate wiring 130 or the emitter 52. The field plate 94 is disposed on the interlayer insulating film 38. In this example, the field plate 94 is connected to the guard ring 92 through a through-hole provided in the interlayer insulating film 38.

[0194] The channel cutoff portion 174 is an N-type or P-type region disposed further outward than the outermost guard ring 92 and exposed on the upper surface 21 of the semiconductor substrate 10. It should be noted that "outer outward" refers to the side where the distance from the active portion 160 increases when viewed from above. That is, the outermost guard ring 92 refers to the guard ring 92 furthest from the active portion 160 in the X-axis direction. In this example, the channel cutoff portion 174 is provided exposed on the upper surface 21 and sidewalls near the end edge 102 of the semiconductor substrate 10. The channel cutoff portion 174 is an N-type region with a higher doping concentration than the bulk doped region 18. The doping concentration of the channel cutoff portion 174 can be higher than the doping concentration of the high-concentration region 460. The channel cutoff portion 174 has the function of terminating the depletion layer generated in the active portion 160 near the end edge 102 of the semiconductor substrate 10. It should be noted that at least a portion of the field plate 94, the outer peripheral gate wiring 130, and the emitter 52 are covered by a protective film such as polyimide or nitride film, although the protective film is sometimes omitted in the accompanying drawings of this specification.

[0195] The second high-concentration region 202 is an N-type region where the donor concentration is higher than the bulk donor doping concentration. The second high-concentration region 202 is disposed between two adjacent guard rings 92. The second high-concentration region 202 can contact the upper surface 21 of the semiconductor substrate 10. In this example, the second high-concentration region 202 extends from the upper surface 21 to a depth shallower than the lower end of the guard rings 92. In other examples, the second high-concentration region 202 can also be disposed deeper than the lower end of the guard rings 92. The second high-concentration region 202 can also be disposed between the well region 11 and the guard rings 92.

[0196] The second high-concentration region 202 can be formed by using the field plate 94 as a mask, through implanting donors from the upper surface 21 of the semiconductor substrate 10 and performing heat treatment. In this case, at least a portion of the second high-concentration region 202 is formed in a region not covered by the field plate 94. In this example, at least a portion of the second high-concentration region 202 does not overlap with the field plate 94 in the Z-axis direction. The donors implanted into the second high-concentration region 202 can be phosphorus, hydrogen, or other donors. When the second high-concentration region 202 is formed at a deeper location, the acceleration energy of the donors can be changed to implant donors at multiple depths.

[0197] In other examples, the second high-concentration region 202 can be formed without using the field plate 94 as a mask by implanting donors from the upper surface 21 of the semiconductor substrate 10 and then performing heat treatment. In this case, boron is selectively implanted as a P-type dopant, and a guard ring is formed by heat treatment. Subsequently, phosphorus is implanted as an N-type dopant, and the second high-concentration region 202 is formed by heat treatment. The heat treatment temperature after implanting the P-type dopant is higher than the heat treatment temperature after implanting the N-type dopant. The dose of the N-type dopant in the ion implantation can be lower than the dose of the P-type dopant. In this case, the N-type dopant ion implantation can be performed either in the region forming the guard ring or selectively in a manner that avoids the region forming the guard ring.

[0198] exist Figure 11 In this example, the second high-concentration region 202 and the high-concentration region 460 are configured separately in the Z-axis direction. A region with the same donor concentration as the bulk donor concentration can be provided between the second high-concentration region 202 and the high-concentration region 460.

[0199] It should be noted that if hydrogen is injected followed by prolonged heat treatment at high temperatures, the hydrogen donors will disappear, or the lifetime adjustment function at the first peak 401 will be lost. Therefore, the hydrogen injection and heat treatment processes are preferably performed in the final stage of the semiconductor device 100 manufacturing process. For example, by injecting hydrogen after forming a protective film over the field plate 94, the disappearance of hydrogen donors can be suppressed.

[0200] If the doping concentration on the upper surface 21 side of the edge termination structure 90 deviates, the extent of depletion layer expansion in the edge termination structure 90 will also deviate. Without the second high-concentration region 202 and the high-concentration region 460, the bulk doped region 18 with high bulk donor concentration occupies a large area on the upper surface 21 side of the edge termination structure 90. Since the bulk donor concentration is the concentration of donors included during the manufacturing of the semiconductor substrate 10, deviations are more likely to occur.

[0201] For this purpose, the second high-concentration region 202 and the high-concentration region 460 are formed by ion implantation or the like. Since the concentration of ion implantation is relatively easy to control, the deviation in donor concentration between the second high-concentration region 202 and the high-concentration region 460 is relatively small. Therefore, by providing the second high-concentration region 202 and the high-concentration region 460, the deviation in the extent of the depletion layer extending from below the well region 11 to the edge terminal structure 90 in the X-axis direction can be reduced, and the breakdown voltage deviation of the semiconductor device 100 can also be reduced. Furthermore, by providing the second high-concentration region 202 and the high-concentration region 460, excessive extension of the depletion layer in the edge terminal structure 90 along the X-axis direction can be suppressed.

[0202] Figure 12 Show Figure 11 The carrier concentration N at the dd line shown C Phosphorus chemical concentration C P VOH defect concentration N VOH and the chemical concentration of impurities C I The distribution example is shown below. In this example, the impurity is hydrogen. That is, the impurity chemical concentration C... I This indicates the hydrogen chemical concentration. The dd line passes through the second high-concentration region 202, the bulk doped region 18, the high-concentration region 460, the buffer zone 20, and the collector region 22 at the edge terminal structure 90. The carrier concentration distribution can be the same as the net doping concentration distribution.

[0203] In this example, the bulk donor is phosphorus. Furthermore, phosphorus is implanted from the upper surface 21 of the semiconductor substrate 10 to form a second high-concentration region 202. In this example, the bulk donor concentration is set to N. B The bulk donor concentration is approximately uniform throughout the entire depth direction. The bulk donor concentration can be the minimum concentration of donors distributed throughout the semiconductor substrate 10. For example, in the case where phosphorus is distributed throughout the semiconductor substrate 10, the bulk donor concentration can be taken as the minimum concentration of phosphorus in the semiconductor substrate 10.

[0204] The phosphorus concentration distribution in the second high-concentration region 202 has a phosphorus concentration peak 318 where the phosphorus concentration reaches a maximum. The depth of the phosphorus concentration peak 318 corresponds to the phosphorus injection site. The hydrogen chemical concentration in the high-concentration region 460 reaches a maximum at the first peak 401.

[0205] The VOH defect density distribution can be a distribution that reflects the hydrogen chemical concentration distribution, or a distribution with a similar shape to the hydrogen chemical concentration distribution. For example, the locations of the maxima, minima, kinks, and other inflection points of each distribution can be located at approximately the same depth. These approximately the same depth locations can have an error, for example, smaller than the full width at half maximum (FWHM) of the first peak 401.

[0206] In this example, the carrier concentration distribution has a peak 408 at the same depth as the first peak 401. Additionally, in the second high-concentration region 202, a peak 314 is present at the same depth as the phosphorus concentration peak 318. When the distance between peaks 408 and 314 is sufficiently large, a bulk doped region 18 is provided between peaks 314 and 408. This bulk doped region 18 has a density corresponding to the bulk donor concentration N. B The corresponding basic carrier concentration N 00 .

[0207] The high-concentration region 460 may have a flat portion 313 with approximately uniform carrier concentration between the first peak 401 and the buffer zone 20. The carrier concentration of the flat portion 313 may vary within a range greater than or less than twice the minimum carrier concentration N0 between the first peak 401 and the buffer zone 20. The carrier concentration of the flat portion 313 may vary within a range greater than or less than 1.5 times the minimum carrier concentration N0, or it may vary within a range greater than or less than 1.2 times the minimum carrier concentration N0. The length of the flat portion 313 in the Z-axis direction may be more than half the length of the high-concentration region 460 in the Z-axis direction. In addition, the carrier concentration of the high-concentration region 460 may gradually decrease from the peak 408 toward the buffer zone 20.

[0208] VOH defect concentration N VOH The distribution at the same depth as the flat portion 313 can also have a flat portion 323. Similarly to the flat portion 313, the VOH defect density of the flat portion 323 can vary within a range above and below twice the minimum VOH defect density between the first peak 401 and the buffer zone 20. For the flat portion 323, the VOH defect density can vary within a range above and below 1.5 times the minimum value, and the VOH defect density can also vary within a range above and below 1.2 times the minimum value. The length of the flat portion 323 in the Z-axis direction can be more than half the length of the high-concentration region 460 in the Z-axis direction.

[0209] The peak carrier concentration N1 in the second high-concentration region 202 is greater than the minimum carrier concentration N0 in the high-concentration region 460. The peak N1 can be more than twice, more than five times, or more than ten times the minimum N0. The peak N1 can be the basic carrier concentration N... 00It can be more than 10 times, or even more than 100 times.

[0210] In this example, buffer 20 has multiple donor concentration peaks 407 at different depths. At least one donor concentration peak 407 can be a hydrogen donor concentration peak. That is, a hydrogen chemical concentration peak can be located at the same depth as the donor concentration peak 407. This hydrogen chemical concentration peak serves as... Figure 2 The second peak 402, as described above, is responsible for its effect. All donor concentration peaks, including 407, can also be hydrogen donor concentration peaks.

[0211] Figure 13A It is shown Figure 8 Figures for other examples of the cc section are shown. In this example, the semiconductor device 100 has a high-concentration region 460 with a depth direction range equal to... Figure 11 The example shown is different. The position of the first peak 401 in the depth direction can also be different. Figure 11 The example shown is different. Other structures are different. Figure 11 The example shown is the same.

[0212] In this example, the high-concentration region 460 is in contact with the guard ring 92. The high-concentration region 460 includes at least the lower end of the guard ring 92. The high-concentration region 460 can also be disposed between two adjacent guard rings 92. In this example, the high-concentration region 460 is not in contact with the second high-concentration region 202. The high-concentration region 460 can be disposed at a position higher than the bottom surface of the trench portion on the upper surface 21 side. That is, the high-concentration region 460 can be disposed all the way to the mesa portion sandwiched by the adjacent trench portion. A bulk doped region 18 with a bulk donor concentration can be disposed between the high-concentration region 460 and the second high-concentration region 202.

[0213] In this example, the first peak 401 is in contact with the guard ring 92. That is, the first peak 401 is positioned above the lower end of the guard ring 92.

[0214] In this example, since the high-concentration region 460 covers the lower end of the protective ring 92, the deviation in donor concentration in areas where the electric field tends to concentrate can be reduced. Therefore, the deviation in withstand voltage can be further reduced.

[0215] Figure 13B It is shown Figure 8 Figures for other examples of the cc section are shown. In this example, the semiconductor device 100 has a high-concentration region 460 with a depth direction range equal to... Figure 13A The example shown is different. The position of the first peak 401 in the depth direction can also be different. Figure 13A The example shown is different. Other structures can be similar. Figure 13A The example shown is the same.

[0216] In this example, the channel cutoff portion 174 contains hydrogen. In this example, the first peak 401 is located at a depth position overlapping with the channel cutoff portion 174. Similarly, the hydrogen chemical concentration peak is located at a position overlapping with the channel cutoff portion 174. That is, hydrogen is distributed from the lower surface 23 of the semiconductor substrate 10 to the depth position overlapping with the channel cutoff portion 174. Hydrogen may be contained in the emitter region 12, the contact region 15, the base region 14, or the accumulation region 16. The first peak 401 may overlap with the emitter region 12, the contact region 15, the base region 14, or the accumulation region 16.

[0217] The high-concentration region 460 extends to a depth overlapping with the channel cutoff portion 174. The high-concentration region 460 may extend up to the upper surface 21 of the semiconductor substrate 10, or it may be positioned further below the upper surface 21. In the region sandwiched between the two guard rings 92, a second high-concentration region 202 may be provided between the high-concentration region 460 and the upper surface 21, or a bulk doped region 18 may be provided.

[0218] In this example, a high-concentration region 460 is provided below the channel stop portion 174, and there is no residual doped region 18. Therefore, it is possible to suppress the depletion layer extending along the X-axis direction to a position further outward than the channel stop portion 174.

[0219] Figure 13C It is shown Figure 8 Figures for other examples of the cc section are shown. In this example, the semiconductor device 100 has a high-concentration region 460 with a depth direction range equal to... Figure 13A or Figure 13B The example shown is different. Furthermore, the first peak 401 is absent within the semiconductor substrate 10. Other structures can be similar. Figure 13A or Figure 13B The example shown is the same.

[0220] In this example, impurities (hydrogen) are implanted through the semiconductor substrate 10 from either the lower surface 23 or the upper surface 21. That is, the acceleration energy of the hydrogen ions is adjusted so that the range of the hydrogen ions is greater than the thickness of the semiconductor substrate 10. Therefore, a first peak 401 is not provided on the semiconductor substrate 10. When implanting hydrogen ions, an absorber such as the shielding member 350 described later can be used, or it can be omitted.

[0221] The high-concentration region 460 extends from the lower surface 23 to the upper surface 21 of the semiconductor substrate 10. In this example, the second high-concentration region 202 may not be provided; alternatively, the second high-concentration region 202 may be provided overlapping the high-concentration region 460.

[0222] In this example, a high-concentration region 460 is provided below the channel cutoff portion 174, and there is no residual doped region 18. Therefore, it is possible to suppress the depletion layer extending along the X-axis direction to a position further outward than the channel cutoff portion 174. In addition, since there is no first peak 401, the impact on the doped regions (e.g., emitter region 12, base region 14, contact region 15, accumulation region 16, well region 11, guard ring 92) locally provided on the upper surface 21 side of the semiconductor substrate 10 can be reduced.

[0223] Figure 14 It is shown Figure 8 Figures show other examples of the cc section. In this example, the semiconductor device 100 is provided with a second high-concentration region 202 and a high-concentration region 460, the depth direction of which is... Figure 11 , Figure 13A , Figure 13B or Figure 13C The example shown is different. Other structures are different. Figure 11 , Figure 13A , Figure 13B or Figure 13C The example shown is the same.

[0224] In this example, a portion of the second high-concentration region 202 and a portion of the high-concentration region 460 are located in the same area. The lower end of the second high-concentration region 202 is disposed within the range of the high-concentration region 460, and the upper end of the high-concentration region 460 is disposed within the range of the second high-concentration region 202. With this structure, the second high-concentration region 202 and the high-concentration region 460 can be connected, thereby reducing the area of ​​bulk donor concentration in the edge terminal structure 90. Therefore, the withstand pressure deviation can be further reduced.

[0225] The second high-concentration region 202 can be formed deeper than the lower end of the guard ring 92. This allows for easy connection between the second high-concentration region 202 and the high-concentration region 460. In other examples, the second high-concentration region 202 can also be formed shallower than the lower end of the guard ring 92. In this example, the first peak 401 is disposed within the second high-concentration region 202. The first peak 401 can be positioned at the contact point with the guard ring 92. This allows the high-concentration region 460 to be formed near the upper surface 21, facilitating easy connection between the second high-concentration region 202 and the high-concentration region 460.

[0226] In the edge terminal structure 90, a bulk doped region 18 with a high concentration of bulk donors may remain at a position further outward than the outermost protective ring 92, or a second high-concentration region 202 may be provided without the bulk doped region 18 remaining. In this example, the bulk doped region 18 is not present. Figure 14 In the example, the second high-concentration region 202 does not cover a portion of the lower end of the protective ring 92. For example... Figure 14As shown by the dashed line, the second high-concentration zone 202 can also cover the entire protective ring 92.

[0227] Figure 15 It is shown Figure 8 Figures for other examples of the cc cross-section. In region 91, which is at least a portion of the edge terminal structure 90, the high-concentration region 460 of the semiconductor device 100 in this example is configured similarly to... Figure 11 , Figure 13A , Figure 13B , Figure 13C or Figure 14 The example shown is different. Alternatively, a third high-concentration region 203 can be provided in region 91 instead of the second high-concentration region 202. The third high-concentration region 203 is a high-concentration region formed at a deeper location than the second high-concentration region 202. One or more of the following can be provided in region 91: bulk doped region 18, second high-concentration region 202, high-concentration region 460, and third high-concentration region 203. Other structures are similar to... Figure 11 , Figure 13A , Figure 13B , Figure 13C or Figure 14 The example shown is the same.

[0228] Figure 15 The high-concentration region 460 is not provided in the predetermined width region 91 of the edge terminal structure 90 that contacts the end edge 102 of the semiconductor substrate 10. Region 91 may include one or more guard rings 92. A bulk doped region 18 with a bulk donor concentration may be provided in region 91 instead of the high-concentration region 460. The high-concentration region 460 may also not be formed in the edge terminal structure 90. The outer peripheral end of the high-concentration region 460 may be located further inward than the innermost guard ring 92. In other examples, the high-concentration region 460 may also be provided in region 91. The length of the high-concentration region 460 in the Z-axis direction of region 91 may be the same as, shorter than, or longer than the length of the high-concentration region 460 disposed further inward than region 91.

[0229] The edge terminal structure 90, which is located further inside region 91, has the same... Figure 11 , Figure 13A , Figure 13B , Figure 13C or Figure 14 The example shown has the same structure. The edge terminal structure 90, located further inside region 91, includes one or more protective rings 92. (As shown...) Figure 11 , Figure 13A , Figure 13B , Figure 13C or Figure 14 As shown, the high concentration zone 460 can be set in the range including the lower end of the protective ring 92, or it can be set in the range excluding the lower end of the protective ring 92.

[0230] A second high-concentration region 202 may be provided in region 91; alternatively, it may not be provided. Alternatively, a third high-concentration region 203 of N-type doped material with a higher donor concentration than the bulk donor concentration may be provided instead of the second high-concentration region 202. The donor concentration of the third high-concentration region 203 may be the same as or different from that of the second high-concentration region 202. The third high-concentration region 203 extends from the upper surface 21 of the semiconductor substrate 10 to a depth greater than the lower end of the second high-concentration region 202. In this example, the third high-concentration region 203 may be located deeper than the lower end of the guard ring 92. A bulk doped region 18 is provided between the third high-concentration region 203 and the buffer zone 20.

[0231] The third high-concentration region 203 can be formed by injecting donors such as phosphorus or hydrogen from the upper surface 21. The injection depth of the donors in the third high-concentration region 203 can be deeper than the injection depth of the donors in the second high-concentration region 202. The heat treatment of the second high-concentration region 202 and the third high-concentration region 203 can be performed separately or together.

[0232] Figure 16 It is shown Figure 8 Figures for other examples of the cc section. In this example, the semiconductor device 100 has a high-concentration region 460 extending over the XY plane, and... Figures 1 to 15 The semiconductor device 100 described herein differs. The range on the XY plane where the first peak 401 is located can also be the same as that in... Figures 1 to 15 The examples described in the text differ. Structures other than the high-concentration region 460 and the first peak 401 can be related to... Figures 1 to 15 The same applies to any of the methods described herein. In Figure 16 In the middle, the configuration of the high-concentration region 460 and the first peak 401 is relative to Figure 11 The example shown is different. Additionally, with... Figure 11 Compared to the example shown, in Figure 16 The example shown does not include a second high-concentration region 202. Other structures are similar. Figure 11 The example shown is the same.

[0233] In this example, at least a portion of the high-concentration region 460 is disposed in the edge terminal structure 90, and the high-concentration region 460 is disposed in a region that does not reach the active part 160. The high-concentration region 460 may be disposed only in the edge terminal structure 90, or it may extend from the edge terminal structure 90 to below the trap region 11. Figure 16In the example, the high-concentration region 460 is disposed from the end of the semiconductor substrate 10 in the X-axis direction to below the well region 11.

[0234] In this example, since the high-concentration region 460 is not provided in the active section 160, it is possible to prevent changes in the characteristics of the active section 160 caused by the provision of the high-concentration region 460. Since the high-concentration region 460 is provided in the edge terminal structure section 90, it is possible to suppress the expansion of the depletion layer in the edge terminal structure section 90, and to reduce the area of ​​the edge terminal structure section 90 on the XY plane.

[0235] Figure 17 It is shown Figure 8 Figures of other examples of the cc cross section. The semiconductor device 100 in this example differs from others in that it has a second high-concentration region 202. Figure 16 The examples described in [the text] differ. Other structures are different from those in [the text]. Figure 16 The semiconductor device 100 described herein is identical to any of the embodiments described herein. In this example, it is also possible to suppress the expansion of the depletion layer in the edge termination structure 90 while preventing changes in the characteristics of the active portion 160.

[0236] Figure 18A It is shown Figure 8 Figures of other examples of the cc cross section. The upper position of the high-concentration region 460 in the Z-axis direction and the position of the first peak 401 in the Z-axis direction of the semiconductor device 100 in this example are compared with... Figure 16 or Figure 17 This differs from any of the examples described. Other structures are similar to those in... Figure 16 or Figure 17 The same applies to any of the examples described herein. Figure 18A In the example shown, with Figure 17 The example also includes a second high-concentration region 202. Furthermore, the upper position of the high-concentration region 460 in the Z-axis direction and the position of the first peak 401 in the Z-axis direction are similar to those in... Figure 13A The example described above is the same. In this example, it is also possible to suppress the expansion of the depletion layer in the edge terminal structure 90 while preventing changes in the characteristics of the active part 160.

[0237] Figure 18B It is shown Figure 8 Figures for other examples of the cc section are shown. In this example, the semiconductor device 100 has a high-concentration region 460 with a depth direction range equal to... Figure 18A The example shown is different. The position of the first peak 401 in the depth direction can also be the same as... Figure 18A The example shown is different. Other structures can be similar. Figure 18A The example shown is the same.

[0238] In this example, the high concentration zone 460 is defined within a certain range, and the depth of the first peak 401 is defined within a certain range. Figure 13B The example is the same. That is, in this example, the first peak 401 is positioned at a depth that overlaps with the channel cutoff portion 174. Similarly, the hydrogen chemical concentration peak is positioned at a depth that overlaps with the channel cutoff portion 174. In this example, the high concentration region 460 is positioned up to a depth that overlaps with the channel cutoff portion 174.

[0239] In this example, a high-concentration region 460 is provided below the channel stop portion 174, and there is no residual doped region 18. Therefore, it is possible to suppress the depletion layer extending along the X-axis direction to a position further outward than the channel stop portion 174.

[0240] Figure 18C It is shown Figure 8 Figures for other examples of the cc section are shown. In this example, the semiconductor device 100 has a high-concentration region 460 with a depth direction range equal to... Figure 18A or Figure 18B The example shown is different. Furthermore, the first peak 401 is absent within the semiconductor substrate 10. Other structures can be similar. Figure 18A or Figure 18B The example shown is the same.

[0241] In this example, with Figure 13C Similarly, in this example, impurities (hydrogen) are implanted through the semiconductor substrate 10 from its lower surface 23. In this example, the depth range of the high concentration region 460 is set to... Figure 13C The example is the same. That is, the high-concentration region 460 is formed from the lower surface 23 to the upper surface 21 of the semiconductor substrate 10.

[0242] In this example, a high-concentration region 460 is provided below the channel cutoff portion 174, and there is no residual doped region 18. Therefore, it is possible to suppress the depletion layer extending along the X-axis direction to a position further outward than the channel cutoff portion 174. In addition, since there is no first peak 401, the impact on the doped regions (e.g., well region 11, guard ring 92) locally provided on the upper surface 21 side of the semiconductor substrate 10 can be reduced.

[0243] Figure 19 It is shown Figure 8 Figures of other examples of the cc section are shown. The structure of the second high-concentration region 202 of the semiconductor device 100 in this example is similar to... Figure 18A , Figure 18B or Figure 18C The example shown is different. Other structures are different. Figure 18A , Figure 18B or Figure 18C The example shown is the same. The second high-concentration region 202 in this example has the same... Figure 14The example shown has the same structure. In this example, it is also possible to suppress the expansion of the depletion layer in the edge terminal structure 90 while preventing changes in the characteristics of the active part 160.

[0244] Figure 20 It is shown Figure 8 Figures of other examples of the cc section are shown. In this example, the semiconductor device 100 has multiple regions of different lengths in the Z-axis direction in the high-concentration region 460, which is different from... Figures 16 to 19 The semiconductor device 100 described herein differs. Furthermore, the position of the first peak 401 along the Z-axis varies in different regions of the high-concentration region 460. Other structures are different from those described herein. Figures 16 to 19 The same applies to any of the examples described herein.

[0245] The high-concentration region 460 has an inner portion and an outer portion located further outward than the inner portion. The outer portion refers to the side on the XY plane furthest from the active part 160. The length of the outer portion in the Z-axis direction is greater than the length of the inner portion in the Z-axis direction. Figure 20 In this example, the high-concentration region 460 includes high-concentration region 460-1, high-concentration region 460-2, and high-concentration region 460-3. High-concentration region 460-2 is positioned further outward than high-concentration region 460-1 and is longer in the Z-axis direction than high-concentration region 460-1. High-concentration region 460-3 is positioned further outward than high-concentration region 460-2 and is longer in the Z-axis direction than high-concentration region 460-2. That is, if high-concentration region 460-1 is considered the inner portion, then high-concentration regions 460-2 and 460-3 are the outer portions. Furthermore, if high-concentration region 460-2 is considered the inner portion, then high-concentration region 460-3 is the outer portion. In this example, the length of each region of the high-concentration region 460 varies in a stepped manner in the Z-axis direction.

[0246] The upper end of each high-concentration zone 460 can be configured within the drift zone 19. In other examples, the upper end of the high-concentration zone 460-3 can be configured at a position overlapping with the guard ring 92 or the trap zone 11.

[0247] In the Z-axis direction, the first peak 401-2 contained in the high concentration region 460-2 is positioned higher than the first peak 401-1 contained in the high concentration region 460-1. In the Z-axis direction, the first peak 401-3 contained in the high concentration region 460-3 is positioned higher than the first peak 401-2 contained in the high concentration region 460-2.

[0248] According to the semiconductor device 100 of this example, since the high-concentration region 460 near the active portion 160 is short in the Z-axis direction, the influence of the high-concentration region 460 on the characteristics of the active portion 160 can be suppressed. In addition, since the high-concentration region 460 far from the active portion 160 is long in the Z-axis direction, the expansion of the depletion layer in the edge termination structure portion 90 can be suppressed.

[0249] Figure 21A It is shown Figure 8 Figures of other examples of the cc section are shown. In this example, the semiconductor device 100 has multiple regions of varying lengths in the Z-axis direction within the high-concentration region 460, which is consistent with... Figures 16 to 19 The semiconductor device 100 described herein differs. Furthermore, the position of the first peak 401 along the Z-axis varies in different regions of the high-concentration region 460. Other structures are different from those described herein. Figures 16 to 19 The same applies to any of the examples described herein.

[0250] In this example, the high-concentration region 460 gradually increases in length along the Z-axis as it moves further away from the active part 160, which is consistent with... Figure 20 The high concentration region 460 is different. Other structures can be related to... Figure 20 The example is similar. In this example, the first peak 401 is positioned upwards as it moves further away from the active part 160. In this example, the upper end of the high-concentration region 460 can be entirely positioned within the drift region 19. In other examples, a portion of the upper end of the high-concentration region 460 can also be positioned to overlap with the guard ring 92 or the trap region 11. In this example, the influence of the high-concentration region 460 on the characteristics of the active part 160 can also be suppressed. In addition, the expansion of the depletion layer in the edge terminal structure 90 can be suppressed.

[0251] Figure 21B It is shown Figure 8 Figures for other examples of the cc cross section. In this example, the semiconductor device 100 is configured with a high-concentration region 460 at a depth range and the position of the first peak 401... Figure 21A The examples differ. Other structures are different. Figure 21A The examples are the same.

[0252] and Figure 21ASimilarly, the depth of the first peak 401 is closer to the upper surface 21 the further away from the active portion 160. Likewise, the depth of the hydrogen chemical concentration peak is closer to the upper surface 21 the further away from the active portion 160. A hydrogen chemical concentration peak can be positioned at the location of the first peak 401. In this example, the first peak 401 overlaps with the channel cutoff portion 174. The first peak 401 may also overlap with one or more guard rings 92. Furthermore, in the region near the sidewall of the semiconductor substrate 10, hydrogen ions injected from the lower surface 23 can also penetrate the semiconductor substrate 10. The first peak 401 is not positioned in the region where hydrogen ions penetrate. For example, the first peak 401 may not be positioned in the region of the channel cutoff portion 174 that contacts the sidewall of the semiconductor substrate 10.

[0253] Furthermore, the length of the high-concentration region 460 gradually increases in the Z-axis direction as it moves further away from the active portion 160. In this example, the high-concentration region 460 is formed from the lower surface 23 to a position where it contacts or overlaps with the channel stop portion 174. In this example, the high-concentration region 460 is provided in the area below the channel stop portion 174, and there are no residual doped regions 18. Therefore, it is possible to suppress the depletion layer extending in the X-axis direction to a position further outward than the channel stop portion 174.

[0254] Figure 22 It is shown in Figure 20 The figure shows an example of a method for forming the high-concentration region 460 as described herein. In this example, with the shielding member 350 configured, hydrogen ions are irradiated from the lower surface 23 side towards the area below the lower surface 23 of the semiconductor substrate 10. The shielding member 350 covers the entire active portion 160 and at least a portion of the edge terminal structure portion 90. The shielding member 350 covering the active portion 160 completely blocks hydrogen ions and just prevents the hydrogen ions from reaching the thickness of the semiconductor substrate 10.

[0255] The shielding member 350 covering the area where the high concentration region 460 should be formed has a thickness corresponding to the length of each high concentration region 460 in the Z-axis direction. That is, the shielding member 350 is thinner in the region where the high concentration region 460 is formed longer. By making the shielding member 350 thinner, hydrogen ions can reach deep into the semiconductor substrate 10, thereby making the high concentration region 460 longer.

[0256] In this example, the shielding member 350 becomes thinner in a stepped manner the further away from the active part 160. The shielding member 350 can be provided below the high concentration region 460-3, or it can be omitted. Although in Figure 22 A collector 24 is provided, but hydrogen ions can also be irradiated onto the lower surface 23 before the collector 24 is formed.

[0257] Figure 23 It is shown in Figure 21AThe diagram illustrates an example of a method for forming the high-concentration region 460 as described in the illustration. In this example, the shape of the shielding member 350 is similar to... Figure 22 The examples are different. Other conditions are the same as... Figure 22 The examples are the same.

[0258] In this example, the shielding member 350 becomes thinner in a straight line or curve as it moves further away from the active part 160. The shielding member 350 may or may not be provided below the high concentration region 460-3.

[0259] exist Figures 16 to 23 In the illustrated configuration, the resistivity of the high-concentration region 460 is lower than that of the drift region 19 in the active section 160 (transistor section 70 or diode section 80). The resistivity of the high-concentration region 460 can be less than 1 / 1.5 and more than 1 / 10 of the resistivity of the drift region 19 in the active section 160. The resistivity of the high-concentration region 460 can be less than 1 / 2 of the resistivity of the drift region 19 in the active section 160. The resistivity of each region can be the value at the center of the Z-axis direction of each region, or it can be the average value.

[0260] exist Figures 16 to 23 In the illustrated configuration, the resistivity of the drift region 19 of the active portion 160 can vary depending on the rated voltage of the semiconductor device 100. For example, at a rated voltage of 600V, the resistivity can be 20–80 Ωcm; at a rated voltage of 1200V, the resistivity can be 40–120 Ωcm; at a rated voltage of 1700V, the resistivity can be 60–200 Ωcm; and at a rated voltage of 3300V, the resistivity can be 150–450 Ωcm.

[0261] exist Figures 1 to 23 In the illustrated configuration, the semiconductor substrate 10 can be integrally distributed with bulk acceptors of the second conductivity type. Similar to bulk donors, bulk acceptors are acceptors uniformly introduced into the blank during blank manufacturing. The bulk acceptor can be boron. The bulk acceptor concentration can be lower than the bulk donor concentration. That is, the blank is N-type. As an example, the bulk acceptor concentration is 5 × 10⁻⁶. 11 ( / cm 3 )~9×10 13 ( / cm 3 The donor concentration is 5 × 10⁻⁶. 12 ( / cm 3 )~1×10 14 ( / cm 3 The concentration of the acceptor can be more than 1%, more than 10%, or more than 50% of the donor concentration. The concentration of the acceptor can be less than 99%, less than 95%, or less than 90% of the donor concentration.

[0262] By ensuring that the bulk acceptor is present throughout the entire semiconductor substrate 10, the net doping concentration in the semiconductor substrate 10 before hydrogen ion implantation can be reduced. Therefore, the absolute value of the deviation in the net doping concentration of the semiconductor substrate 10 can be reduced. Consequently, adjustment of the resistivity based on hydrogen ion implantation becomes easier.

[0263] exist Figures 1 to 7 The oxygen annealing described in the text can form Figures 8 to 23 The oxygen annealing is performed before the structures described herein, except for the bulk doped region 18. In other examples, oxygen annealing may also be performed after the formation of each doped region inside the semiconductor substrate 10. In this case, the interlayer insulating film 38, the gate insulating film 42, and other individual films can be formed after oxygen annealing. As a result, the degradation of the properties of the insulating films, etc., due to oxygen annealing can be suppressed.

[0264] Furthermore, before oxygen annealing, an N-type dopant such as phosphorus can be implanted onto the upper surface of the semiconductor substrate 10. The N-type dopant can be selectively implanted in a top-view view or implanted onto the entire surface. The N-type dopant can also be implanted into the region forming the third high-concentration region 203. After implanting the N-type dopant, the semiconductor substrate 10 is annealed in an oxygen atmosphere at a temperature above 1100°C and below 1300°C for at least 20 hours (first annealing). This allows the N-type dopant to diffuse to a relatively deep location. The N-type dopant can diffuse until it reaches the high-concentration region 460. This allows the donor concentration of the semiconductor substrate 10 to be adjusted throughout the entire depth direction. It should be noted that the first annealing introduces oxygen into the semiconductor substrate 10 at a concentration equal to the solid solution limit.

[0265] Next, the semiconductor substrate 10 is annealed at a lower temperature than the first annealing (second annealing). The second annealing can be performed in an oxygen atmosphere. The annealing time for the second annealing can be shorter than that for the first annealing. For example, the first annealing is at or above 900°C and below 1000°C, and for 15 hours or less. As a result, oxygen in the semiconductor substrate 10 diffuses outward, forming an oxygen reduction region 450 on the upper surface side. After the second annealing, a structure other than the third high-concentration region 203 can be formed. The second annealing can also be included in the process of forming the structure on the upper surface 21 side of the semiconductor substrate 10.

[0266] It should be noted that the temperature of the first annealing can be below 1000°C. In this case, the introduction of oxygen into the semiconductor substrate 10 can be suppressed during the first annealing.

[0267] 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.

[0268] 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 having bulk donors of a first conductivity type distributed throughout it; The high-concentration region of the first conductivity type includes the central position in the depth direction of the semiconductor substrate, and the donor concentration is higher than the doping concentration of the bulk donor. as well as An oxygen reduction region on the upper surface is formed inside the semiconductor substrate and in contact with the upper surface of the semiconductor substrate, and the closer it is to the upper surface of the semiconductor substrate, the lower the oxygen concentration. The high-concentration region extends from a position that does not contact the upper surface of the semiconductor substrate to the lower surface of the semiconductor substrate. The end of the high-concentration zone on the upper surface side is located in the oxygen-reduced zone on the upper surface side.

2. The semiconductor device according to claim 1, characterized in that, At the end of the high concentration region in the depth direction, there is a first peak where the chemical concentration distribution of impurities becomes a peak.

3. The semiconductor device according to claim 2, characterized in that, The first peak is located at the end of the high concentration region near the upper surface and in the oxygen-reduced region on the upper surface side.

4. The semiconductor device according to claim 3, characterized in that, The chemical concentration distribution of the semiconductor substrate in the depth direction has a maximum value region, which is a region including the location where the chemical concentration is at its maximum value and the chemical concentration is more than 50% of the maximum value.

5. The semiconductor device according to claim 4, characterized in that, The impurity chemical concentration distribution has a second peak of hydrogen chemical concentration located between the first peak and the lower surface.

6. The semiconductor device according to claim 5, characterized in that, The semiconductor device further includes a lower surface-side oxygen reduction region, which is positioned further down the lower surface than the upper surface-side oxygen reduction region, and the closer it is to the lower surface of the semiconductor substrate, the lower the oxide concentration. The second peak of the hydrogen chemical concentration is located in the oxygen-reduced region on the lower surface side.

7. The semiconductor device according to claim 1, characterized in that, The high-concentration zone is set until it overlaps with the oxygen-reducing zone on the upper surface.

8. The semiconductor device according to claim 4, characterized in that, In a portion of the depth direction of the semiconductor substrate, the maximum value region overlaps with the high concentration region.

9. A semiconductor device, characterized in that, have: A semiconductor substrate having an upper surface and a lower surface, and having bulk donors of a first conductivity type distributed throughout it; The high-concentration region of the first conductivity type includes the central position in the depth direction of the semiconductor substrate, and the donor concentration is higher than the doping concentration of the bulk donor. An oxygen reduction region on the upper surface is provided inside the semiconductor substrate and in contact with the upper surface of the semiconductor substrate, and the closer it is to the upper surface of the semiconductor substrate, the lower the oxygen concentration. The maximum value region is a region that includes the location where the chemical concentration reaches its maximum value and the chemical concentration is more than 50% of the maximum value. as well as The lower surface-side oxygen reduction region is positioned further down the lower surface than the upper surface-side oxygen reduction region, and the closer it is to the lower surface of the semiconductor substrate, the lower the oxygen concentration. The high-concentration region extends from a position that does not contact the upper surface of the semiconductor substrate to the lower surface of the semiconductor substrate. The end of the high concentration zone near the upper surface is located within the maximum value zone.

10. The semiconductor device according to claim 9, characterized in that, At the end of the high concentration region in the depth direction, there is a first peak where the chemical concentration distribution of impurities becomes a peak.

11. The semiconductor device according to claim 10, characterized in that, The first peak is located at the end of the high concentration region near the upper surface and within the maximum value region.

12. The semiconductor device according to claim 2 or 11, characterized in that, The depth-direction distribution of the impurity chemical concentration has a lower sloping edge where the impurity chemical concentration decreases from the first peak toward the lower surface, and an upper sloping edge where the impurity chemical concentration decreases more sharply from the first peak toward the upper surface than the lower sloping edge.

13. The semiconductor device according to claim 2 or 11, characterized in that, The high-concentration region extends from the first peak to the lower surface of the semiconductor substrate.

14. The semiconductor device according to any one of claims 2 to 10, characterized in that, The oxidative concentration distribution has an oxygen concentration peak where the oxidative concentration reaches a maximum value.

15. The semiconductor device according to claim 10, characterized in that, The impurity chemical concentration distribution has a second peak of hydrogen chemical concentration located between the first peak and the lower surface.

16. The semiconductor device according to claim 15, characterized in that, The second peak of the hydrogen chemical concentration is located in the oxygen-reduced region on the lower surface side.

17. The semiconductor device according to claim 5 or 15, characterized in that, The second peak of the hydrogen chemical concentration is located in the maximum value region.

18. The semiconductor device according to claim 5 or 15, characterized in that, The semiconductor device also includes: A drift region of a first conductivity type is disposed on the semiconductor substrate; and A buffer zone, disposed between the drift region and the lower surface, has a higher doping concentration than the drift region. The second peak of the hydrogen chemical concentration is positioned in the buffer zone.

19. The semiconductor device according to claim 4 or 10, characterized in that, The recombination center concentration distribution along the depth direction of the semiconductor substrate has a recombination concentration peak. The composite concentration peak is located in the region where the chemical concentration is more than 70% of the maximum value.

20. The semiconductor device according to claim 4 or 10, characterized in that, The first peak is located in the region where the chemical concentration is more than 70% of the maximum value.

21. The semiconductor device according to claim 2 or 10, characterized in that, The chemical concentration of the impurities is the chemical concentration of hydrogen.

22. The semiconductor device according to any one of claims 1 to 10, characterized in that, The donor is either phosphorus or antimony.

23. The semiconductor device according to any one of claims 1 to 10, characterized in that, The semiconductor substrate is generally distributed with bulk acceptors of the second conductivity type.

24. The semiconductor device according to claim 23, characterized in that, The acceptor of the body is boron.

25. The semiconductor device according to any one of claims 1 to 10, characterized in that, The semiconductor device also includes: One or more protective rings are in contact with the upper surface of the semiconductor substrate and have a second conductivity type; and The channel cutoff portion of the first or second conductivity type is disposed at a position further outward than the outermost guard ring, in contact with the upper surface of the semiconductor substrate, and has a higher doping concentration than the bulk donor. The channel stop section contains hydrogen.

26. The semiconductor device according to claim 25, characterized in that, Hydrogen is distributed from the lower surface of the semiconductor substrate to the channel cutoff portion.

27. The semiconductor device according to claim 25, characterized in that, A peak for hydrogen chemical concentration is provided at the cutoff section of the channel.

28. The semiconductor device according to claim 26, characterized in that, A peak for hydrogen chemical concentration is provided at the cutoff section of the channel.

29. The semiconductor device according to claim 9, characterized in that, In a portion of the depth direction of the semiconductor substrate, the maximum value region overlaps with the high concentration region.

30. The semiconductor device according to any one of claims 1 to 10, characterized in that, An emitter region of a first conductivity type is disposed on the upper surface of the semiconductor substrate.

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