Semiconductor device and method for manufacturing semiconductor device

Abstract

Provided is a semiconductor device provided with a semiconductor substrate having an upper surface and a lower surface, the semiconductor substrate having one or more hydrogen peaks in the depth direction, the hydrogen peaks being peaks of hydrogen chemical concentration, the one or more hydrogen peaks including a deepest peak farthest from the lower surface of the semiconductor substrate, the deepest peak including a deepest peak farthest from the lower surface of the semiconductor substrate, and the deepest peak including a deepest peak farthest from the deepest peak. The semiconductor substrate has: a lower region which is a region from the lower surface to the deepest peak; and an upper region that is disposed from the deepest peak to the upper surface, the concentration of the lower region being at least twice the concentration of the upper region with respect to the carbon chemical concentration and / or the oxidation chemical concentration.

Description

Technical Field

[0001] The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device. Background Art

[0002] There is known a semiconductor device obtained by implanting hydrogen ions such as protons into a semiconductor substrate (see, for example, Patent Documents 1 and 2).

[0003] Prior art literature Patent Literature Patent Document 1: U.S. Patent Application Publication No. 2016 / 0141399 Patent Document 2: U.S. Patent Application Publication No. 2015 / 0076650 Summary of the invention

[0004] Technical issues Hydrogen donors are formed by implanting hydrogen ions such as protons into a semiconductor substrate. However, the degree of hydrogen ion donors varies depending on the oxygen concentration or carbon concentration in the semiconductor substrate, resulting in fluctuations in the donor concentration.

[0005] Technical Solution In order to solve the above-mentioned problems, in a first embodiment of the present invention, a semiconductor device is provided, which has a semiconductor substrate, and the semiconductor substrate has an upper surface and a lower surface. In the above-mentioned semiconductor device, the semiconductor substrate may have one or more hydrogen peaks as peaks of hydrogen chemical concentration in the depth direction, and the one or more hydrogen peaks may include the deepest peak farthest from the lower surface of the semiconductor substrate. In any of the above-mentioned semiconductor devices, the semiconductor substrate may have: a lower side region, which is a region from the lower surface to the deepest peak; and an upper side region, which is a region configured from the deepest peak to the upper surface. In any of the above-mentioned semiconductor devices, for at least one of the carbon chemical concentration and the oxygen chemical concentration, the concentration of the lower side region may be more than twice the concentration of the upper side region.

[0006] In any of the above semiconductor devices, the semiconductor substrate may have a drift region of the first conductivity type. In any of the above semiconductor devices, the semiconductor substrate may have a buffer region of the first conductivity type, the buffer region of the first conductivity type being arranged between the lower surface and the drift region and having a doping concentration higher than that of the drift region. In any of the above semiconductor devices, the deepest peak may be arranged in the buffer region.

[0007] In any of the semiconductor devices described above, the lower region may have a flat portion in which at least one of the carbon chemical concentration and the oxygen chemical concentration is uniform.

[0008] In any of the above-mentioned semiconductor devices, the lower region may have one or more carbon peaks as peaks of the carbon chemical concentration in the depth direction.

[0009] In any of the above semiconductor devices, the lower region may have a plurality of carbon peaks in the depth direction.

[0010] In any of the semiconductor devices described above, the lower region may have a plurality of the hydrogen peaks in the depth direction. In any of the semiconductor devices described above, at least one carbon peak may be arranged between two hydrogen peaks in the depth direction.

[0011] In any of the above semiconductor devices, the upper region may have one or more carbon peaks.

[0012] In any of the above-mentioned semiconductor devices, the lower region may have one or more oxygen peaks as peaks of the oxygen chemical concentration in the depth direction.

[0013] In any of the above-mentioned semiconductor devices, the lower region may have a plurality of the oxygen peaks in the depth direction.

[0014] In any of the semiconductor devices described above, the lower region may have a plurality of the hydrogen peaks in the depth direction. In any of the semiconductor devices described above, at least one oxygen peak may be arranged between two hydrogen peaks in the depth direction.

[0015] In any of the above semiconductor devices, the upper region may have one or more oxygen peaks.

[0016] In any of the above-mentioned semiconductor devices, the lower region may have one or more carbon peaks as peaks of the carbon chemical concentration and one or more oxygen peaks as peaks of the oxygen chemical concentration in the depth direction.

[0017] In any of the above semiconductor devices, at least one of the carbon peaks and at least one of the oxygen peaks may be arranged at the same depth position.

[0018] In any of the semiconductor devices described above, the lower region may have a plurality of doping concentration peaks in the depth direction. In any of the semiconductor devices described above, the plurality of doping concentration peaks may have a plurality of first doping concentration peaks corresponding to the plurality of hydrogen peaks. In any of the semiconductor devices described above, the plurality of doping concentration peaks may have a second doping concentration peak disposed between two of the hydrogen peaks.

[0019] In any of the above semiconductor devices, at least one of the carbon peaks may be arranged at a depth position different from that of any of the oxygen peaks.

[0020] In any of the above semiconductor devices, the carbon chemical concentration in the lower region may be 1×10 14 atoms / cm 3 above.

[0021] In any of the above semiconductor devices, the oxygen chemical concentration of the lower region may be 2×10 17 atoms / cm 3 above.

[0022] In a second aspect of the present invention, a method for manufacturing a semiconductor device is provided. The semiconductor device may include a semiconductor substrate, the semiconductor substrate having an upper surface and a lower surface, the semiconductor substrate having one or more hydrogen peaks as peaks of hydrogen chemical concentration in the depth direction, the one or more hydrogen peaks including the deepest peak farthest from the lower surface of the semiconductor substrate, the semiconductor substrate having: a lower region, which is a region from the lower surface to the deepest peak; and an upper region, which is a region configured from the deepest peak to the upper surface. In the above manufacturing method, at least one of carbon, oxygen and silicon may be implanted into the region where the lower region is to be formed. In any of the above manufacturing methods, the semiconductor substrate may be annealed at a temperature of 700°C or higher. In any of the above manufacturing methods, hydrogen ions may be implanted into the depth position where the one or more hydrogen peaks are to be formed.

[0023] The above invention summary does not list all the essential features of the present invention. In addition, sub-combinations of these feature groups can also become inventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a plan view showing an example of a semiconductor device 100 according to an embodiment of the present invention.

[0025] Figure 2 yes Figure 1 Magnified view of area D in FIG.

[0026] Figure 3 It is shown Figure 2 A diagram showing an example of an ee cross section in .

[0027] Figure 4 It is shown Figure 3 A diagram showing an example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line.

[0028] Figure 5 It is shown Figure 3 A diagram showing another example of the distributions of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line.

[0029] Figure 6 It is shown Figure 3 A diagram showing another example of the distributions of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line.

[0030] Figure 7 It is shown Figure 3 A diagram showing another example of the distributions of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line.

[0031] Figure 8 It is shown Figure 3 A diagram showing another example of the distributions of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line.

[0032] Fig. 9 This is a diagram showing an example of the relative positions of the oxygen peak 232 and the carbon peak 242 .

[0033] Fig.10 This is a diagram showing another example of the relative positions of the oxygen peak 232 and the carbon peak 242 .

[0034] Fig.11 It is shown Figure 3 A diagram showing another example of the distributions of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line.

[0035] Fig.12 It is shown Figure 3 FIG. 1 is a diagram showing another example of the distribution of oxygen chemical concentration and carbon chemical concentration at the ff line.

[0036] Fig.13 The diagram shows a part of the steps of the method for manufacturing the semiconductor device 100 .

[0037] Fig.14 1 is a diagram schematically showing a method for manufacturing the semiconductor device 100 .

[0038] Explanation of symbols 10…semiconductor substrate, 11…well region, 12…emitter region, 14…base region, 15…contact region, 16…accumulation region, 18…drift region, 20…buffer region, 21…upper surface, 22…collector region, 23…lower surface, 24…collector electrode, 29…straight line portion, 30…dummy groove portion, 31…front end portion, 32…dummy insulating film, 34…dummy conductive portion, 38…interlayer insulating film, 39…straight line portion, 40…gate groove portion, 41…front end portion, 42…gate insulating film, 44…gate conductive portion, 52…emitter electrode , 54…contact hole, 60, 61…mesa portion, 70…transistor portion, 80…diode portion, 81…extension region, 82…cathode region, 90…edge terminal structure portion, 100…semiconductor device, 130…peripheral gate wiring, 131…active side gate wiring, 160…active portion, 162…edge, 164…gate pad, 201…lower side region, 202…upper side region, 211…doping concentration peak, 213…second doping concentration peak, 221…hydrogen peak, 231…flat portion, 232…oxygen peak, 242…carbon peak DETAILED DESCRIPTION

[0039] Hereinafter, the present invention will be described by way of the embodiments of the invention, but the following embodiments do not limit the invention involved in the claims. In addition, all combinations of features described in the embodiments are not necessarily essential to the technical means of the invention.

[0040] In this specification, one side in a direction parallel to the depth direction of the semiconductor substrate is referred to as "upper", and the other side is referred to as "lower". Of the two main surfaces of a substrate, layer, or other component, one surface is referred to as an upper surface, and the other surface is referred to as a lower surface. The directions of "upper" and "lower" are not limited to the direction of gravity or the direction when the semiconductor device is actually installed.

[0041] In this specification, sometimes the rectangular coordinate axes of the X-axis, Y-axis, and Z-axis are used to explain technical matters. The rectangular coordinate axes only determine the relative positions of the components and do not limit specific directions. For example, the Z-axis is not limited to indicating the height direction relative to the ground. It should be noted that the +Z-axis direction and the -Z-axis direction are opposite directions to each other. When the Z-axis direction is recorded without recording the positive or negative, it refers to the direction parallel to the +Z-axis and the -Z-axis.

[0042] In this specification, the orthogonal axes parallel to the upper surface and the lower surface of the semiconductor substrate are referred to as the X-axis and the Y-axis. In addition, the axis perpendicular to the upper surface and the lower surface of the semiconductor substrate is referred to as the Z-axis. In this specification, the direction of the Z-axis is sometimes referred to as the depth direction. In addition, in this specification, the direction including the X-axis and the Y-axis and parallel to the upper surface and the lower surface of the semiconductor substrate is sometimes referred to as the horizontal direction.

[0043] In addition, the region from the center in the depth direction of the semiconductor substrate to the upper surface of the semiconductor substrate is sometimes referred to as the upper surface side. Similarly, the region from the center in the depth direction of the semiconductor substrate to the lower surface of the semiconductor substrate is sometimes referred to as the lower surface side.

[0044] In this specification, when the term "same" or "equal" is used, it may include a case where there is an error due to manufacturing variation, etc. The error is within 10%, for example.

[0045] In this specification, the conductivity type of the doped region doped with impurities is set to P type or N type for description. In this specification, impurities sometimes specifically refer to either N-type donors or P-type acceptors, and are sometimes described as dopants. In this specification, doping refers to the process of introducing donors or acceptors into a semiconductor substrate to form a semiconductor showing N-type conductivity or a semiconductor showing P-type conductivity.

[0046] In this specification, the doping concentration refers to the concentration of donors or acceptors in thermal equilibrium. In this specification, the net doping concentration refers to the actual concentration obtained by adding the polarity of the charges when the donor concentration is set to the concentration of positive ions and the acceptor concentration is set to the concentration of negative ions. As an example, if the donor concentration is set to N D , and the acceptor concentration is set to N A , then the net doping concentration at any position becomes N D -N A In this specification, the net doping concentration may be described simply as the doping concentration.

[0047] The donor has the function of supplying electrons to the semiconductor. The acceptor has the function of taking electrons from the semiconductor. The donor and the acceptor are not limited to the impurities themselves. For example, a VOH defect formed by the combination of vacancies (V), oxygen (O) and hydrogen (H) present in a semiconductor functions as a donor that supplies electrons. A hydrogen donor can be a donor that combines with at least a vacancy (V) and hydrogen (H). Alternatively, intercrystalline Si-H formed by the combination of intercrystalline silicon (Si-i) and hydrogen, and CiOi-H formed by the combination of intercrystalline carbon (Ci) and intercrystalline oxygen (Oi) and hydrogen in a silicon semiconductor also function as donors that supply electrons. In this specification, VOH defects, CiOi-H or intercrystalline Si-H are sometimes referred to as hydrogen donors.

[0048] In this specification, the semiconductor substrate is distributed with N-type body donors as a whole. Body donors are donors formed by dopants contained roughly uniformly in the ingot when manufacturing the ingot that serves as the basis of the semiconductor substrate. The body donor in this example is an element other than hydrogen. Although the dopant of the body donor is, for example, phosphorus, antimony, arsenic, selenium or sulfur, it is not limited to this. The body donor in this example is phosphorus. Body donors are also included in the P-type region. The semiconductor substrate can be a wafer cut from a semiconductor ingot or a chip formed by singulating the wafer. The semiconductor ingot can be manufactured by any of the CZ method, the magnetron crystal pulling method (MCZ method), and the floating zone melting method (FZ method). The ingot in this example is manufactured by the MCZ method. The oxygen concentration contained in the substrate manufactured by the MCZ method is 1×10 17 ~7×10 17 / cm 3 The oxygen concentration of the substrate produced by the FZ method is 1×10 15 ~5×10 16 / cm 3 There is a tendency that hydrogen donors are more likely to be generated when the oxygen concentration is high. The body donor concentration can use the chemical concentration of body donors distributed throughout the semiconductor substrate, or it can be a value between 90% and 100% of the chemical concentration. In addition, the semiconductor substrate can also use an undoped substrate that does not contain dopants such as phosphorus. In this case, the body donor concentration (D0) of the undoped substrate is, for example, 1×10 10 / cm 3 Above and 5×10 12 / cm 3 The bulk donor concentration (D0) of the undoped substrate is preferably 1×10 11 / cm 3 The bulk donor concentration (D0) of the undoped substrate is preferably 5×10 12 / cm 3 Hereinafter, each concentration in the present invention may be a value at room temperature. As an example, a value at room temperature may be a value at 300K (Kelvin) (approximately 26.9° C.).

[0049] In the case of being recorded as P+ type or N+ type in this specification, it means that the doping concentration is higher than the doping concentration of P type or N type, and in the case of being recorded as P- type or N- type, it means that the doping concentration is lower than the doping concentration of P type or N type. In addition, in the case of being recorded as P++ type or N++ type in this specification, it means that the doping concentration is higher than the doping concentration of P+ type or N+ type. Unless otherwise specified, the unit system in this specification is the SI unit system. Although the unit of length is sometimes expressed in cm, each calculation can be performed after conversion to meters (m).

[0050] In this specification, chemical concentration refers to the atomic density of impurities measured independently of the state of electrical activation. Chemical concentration can be measured by, for example, secondary ion mass spectrometry (SIMS). The above-mentioned net doping concentration can be measured by voltage-capacitance measurement (CV method). In addition, the carrier concentration measured by the extended resistance measurement method (SR method) can be used as the net doping concentration. The carrier concentration measured by the CV method or the SR method can be set to a value in a thermal equilibrium state. In addition, in the N-type region, the donor concentration is much greater than the acceptor concentration, so the carrier concentration in the region can also be set to the donor concentration. Similarly, in the P-type region, the carrier concentration in the region can also be set to the acceptor concentration. In this specification, the doping concentration of the N-type region is sometimes referred to as the donor concentration, and the doping concentration of the P-type region is sometimes referred to as the acceptor concentration.

[0051] When the concentration distribution of the donor, acceptor or net doping has a peak, the peak value can be used as the concentration of the donor, acceptor or net doping in the region. When the concentration of the donor, acceptor or net doping is almost uniform, the average value of the concentration of the donor, acceptor or net doping in the region can also be used as the concentration of the donor, acceptor or net doping. In this specification, atoms / cm is used to express the concentration per unit volume. 3 or / cm 3 This unit is used for donor or acceptor concentration or chemical concentration in a semiconductor substrate. The atoms symbol can also be omitted.

[0052] The carrier concentration measured by the SR method can be lower than the concentration of the donor or acceptor. In the range of current flow when measuring the spreading resistance, the carrier mobility of the semiconductor substrate may be lower than the value of the carrier mobility in the crystalline state. The disorder (disorder) of the crystal structure caused by lattice defects, etc., scatters the carriers, resulting in a decrease in carrier mobility.

[0053] The concentration of donors or acceptors calculated from the carrier concentration measured by the CV method or the SR method can be lower than the chemical concentration of the element representing the donor or acceptor. For example, the donor concentration of phosphorus or arsenic, which is a donor, or the acceptor concentration of boron, which is an acceptor, in a silicon semiconductor is about 99% of their chemical concentrations. On the other hand, the donor concentration of hydrogen, which is a donor, in a silicon semiconductor is about 0.1% to 10% of the chemical concentration of hydrogen.

[0054] Figure 1 FIG. 1 is a top view showing an example of a semiconductor device 100 according to an embodiment of the present invention. Figure 1 , the positions of the components projected onto the upper surface of the semiconductor substrate 10 are shown. Figure 1 In FIG. 1 , only some components of the semiconductor device 100 are shown, and some components are omitted.

[0055] The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 is a substrate formed of a semiconductor material. As an example, the semiconductor substrate 10 is a silicon substrate. The semiconductor substrate 10 has an edge 162 when viewed from above. In this specification, the condition referred to as viewed from above refers to the condition observed from the upper surface side of the semiconductor substrate 10. The semiconductor substrate 10 of this example has two sets of edge 162 that are opposite to each other when viewed from above. Figure 1 In the embodiment, the X-axis and the Y-axis are parallel to one of the end sides 162. In addition, the Z-axis is perpendicular to the upper surface of the semiconductor substrate 10.

[0056] The semiconductor substrate 10 is provided with an active portion 160. The active portion 160 is a region where a main current flows in the depth direction between the upper surface and the lower surface of the semiconductor substrate 10 when the semiconductor device 100 is in operation. An emitter electrode is provided above the active portion 160, but Figure 1 The active portion 160 may refer to a region overlapping with the emitting electrode in a plan view. In addition, a region sandwiched by the active portion 160 in a plan view may also be included in the active portion 160.

[0057] The active portion 160 is provided with at least one of a transistor portion 70 including a transistor element such as an IGBT (Insulated Gate Bipolar Transistor) and a diode portion 80 including a diode element such as a freewheeling diode (FWD). Figure 1 In the example, the transistor portions 70 and the diode portions 80 are alternately arranged along a predetermined arrangement direction (in this example, the X-axis direction) on the upper surface of the semiconductor substrate 10. The semiconductor device 100 of this example is a reverse conducting IGBT (RC-IGBT).

[0058] exist Figure 1 In the figure, the region where the transistor portion 70 is arranged is marked with a symbol "I", and the region where the diode portion 80 is arranged is marked with a symbol "F". In this specification, the direction perpendicular to the arrangement direction in a plan view is sometimes referred to as the extension direction (in Figure 1 The transistor portion 70 and the diode portion 80 may each have a long side in the extension direction. That is, the length of the transistor portion 70 in the Y-axis direction is greater than the width in the X-axis direction. Similarly, the length of the diode portion 80 in the Y-axis direction is greater than the width in the X-axis direction. The extension direction of the transistor portion 70 and the diode portion 80 may be the same as the long side direction of each groove portion described later.

[0059] The diode portion 80 has an N+ type cathode region in the region in contact with the lower surface of the semiconductor substrate 10. In this specification, the region in which the cathode region is provided is referred to as the diode portion 80. That is, the diode portion 80 is a region overlapping with the cathode region when viewed from above. On the lower surface of the semiconductor substrate 10, a P+ type collector region may be provided in a region other than the cathode region. In this specification, the diode portion 80 sometimes also includes 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.

[0060] The transistor section 70 has a P+ type collector region in a region in contact with 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.

[0061] The semiconductor device 100 may have one or more pads above the semiconductor substrate 10. The semiconductor device 100 of this example has a gate pad 164. The semiconductor device 100 may also have pads such as an anode pad, a cathode pad, and a current detection pad. Each pad is arranged near the end 162. The vicinity of the end 162 refers to the area between the end 162 and the emitter electrode when viewed from above. When the semiconductor device 100 is actually installed, each pad can be connected to an external circuit via wiring such as a wire.

[0062] A gate potential is applied to the gate pad 164. The gate pad 164 is electrically connected to the conductive portion of the gate trench portion of the active portion 160. The semiconductor device 100 includes a gate wiring that connects the gate pad 164 to the gate trench portion. Figure 1 In the figure, the gate wiring is shaded with diagonal lines.

[0063] The gate wiring of this example has a peripheral gate wiring 130 and an active side gate wiring 131. The peripheral gate wiring 130 is arranged between the active portion 160 and the end 162 of the semiconductor substrate 10 when viewed from above. The peripheral gate wiring 130 of this example surrounds the active portion 160 when viewed from above. The area surrounded by the peripheral gate wiring 130 when viewed from above can also be set as the active portion 160. In addition, a well region is formed below the gate wiring. The well region refers to a P-type region with a higher concentration than the base region described later, and is formed from the upper surface of the semiconductor substrate 10 to a position deeper than the base region. The area surrounded by the well region when viewed from above can also be set as the active portion 160.

[0064] The peripheral gate wiring 130 is connected to the gate pad 164. The peripheral gate wiring 130 is arranged above the semiconductor substrate 10. The peripheral gate wiring 130 may be a metal wiring containing aluminum or the like.

[0065] The active-side gate wiring 131 is provided in the active portion 160. Since the active-side gate wiring 131 is provided in the active portion 160, the variation in wiring length from the gate pad 164 in each region of the semiconductor substrate 10 can be reduced.

[0066] The peripheral gate wiring 130 and the active side gate wiring 131 are connected to the gate groove portion of the active portion 160. The peripheral gate wiring 130 and the active side gate wiring 131 are arranged above the semiconductor substrate 10. The peripheral gate wiring 130 and the active side gate wiring 131 may be wiring formed of a semiconductor such as polysilicon doped with impurities.

[0067] The active-side gate wiring 131 may be connected to the peripheral gate wiring 130. The active-side gate wiring 131 of this example is provided to extend in the X-axis direction so as to cross the active portion 160 from the peripheral gate wiring 130 on one side sandwiching the active portion 160 to the peripheral gate wiring 130 on the other side at the approximate center in the Y-axis direction. When the active portion 160 is divided by the active-side gate wiring 131, the transistor portion 70 and the diode portion 80 may be alternately arranged in the X-axis direction in each divided region.

[0068] In addition, 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 detection unit (not shown) which simulates the operation of a transistor unit provided in the active unit 160 .

[0069] In a plan view, the semiconductor device 100 of this example includes an edge termination structure portion 90 between the active portion 160 and the edge 162. The edge termination structure portion 90 of this example is arranged between the peripheral gate wiring 130 and the edge 162. The edge termination structure portion 90 alleviates the electric field concentration on the upper surface side of the semiconductor substrate 10. The edge termination structure portion 90 may include at least one of a guard ring, a field plate, and a surface electric field reduction portion that surrounds the active portion 160 and is provided in an annular shape.

[0070] Figure 2 yes Figure 1 1 is an enlarged view of the region D in FIG. The region D is a region including the transistor portion 70, the diode portion 80, and the active side gate wiring 131. The semiconductor device 100 of this example includes a gate groove portion 40, a dummy groove portion 30, a well region 11, an emitter region 12, a base region 14, and a contact region 15 provided inside the upper surface side of the semiconductor substrate 10. The gate groove portion 40 and the dummy groove portion 30 are each an example of a groove portion. In addition, the semiconductor device 100 of this example includes an emitter electrode 52 and an active side gate wiring 131 provided above the upper surface of the semiconductor substrate 10. The emitter electrode 52 and the active side gate wiring 131 are provided separately from each other.

[0071] An interlayer insulating film is provided between the emitter electrode 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. Figure 2 In this example, the interlayer insulating film is provided with a contact hole 54 so as to penetrate the interlayer insulating film. Figure 2 In FIG. 1 , each contact hole 54 is shaded with diagonal lines.

[0072] The emitter electrode 52 is disposed above the gate groove portion 40, the dummy groove portion 30, the well region 11, the emitter region 12, the base region 14, and the contact region 15. The emitter electrode 52 contacts the emitter region 12, the contact region 15, and the base region 14 on the upper surface of the semiconductor substrate 10 through the contact hole 54. In addition, the emitter electrode 52 is connected to the dummy conductive portion in the dummy groove portion 30 through the contact hole provided in the interlayer insulating film. The front end of the emitter electrode 52 in the Y-axis direction of the dummy groove portion 30 may be connected to the dummy conductive portion of the dummy groove portion 30. The dummy conductive portion of the dummy groove portion 30 may not be connected to the emitter electrode 52 and the gate conductive portion, or may be controlled to a potential different from the potential of the emitter electrode 52 and the potential of the gate conductive portion.

[0073] The active side gate wiring 131 is connected to the gate groove 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 groove portion 40 at the front end portion 41 in the Y-axis direction of the gate groove portion 40. The active side gate wiring 131 is not connected to the dummy conductive portion in the dummy groove portion 30.

[0074] The emitter electrode 52 is formed of a material including metal. Figure 2 , the range where the emitter electrode 52 is provided is shown in FIG. For example, at least a portion of the emitter electrode 52 is formed of aluminum or an aluminum-silicon alloy, such as a metal alloy such as AlSi or AlSiCu. The emitter electrode 52 may have a barrier metal formed of titanium or a titanium compound, etc., in the lower layer of the region formed of aluminum, etc. Furthermore, a plug formed by embedding tungsten, etc., in a manner in contact with the barrier metal and aluminum, etc., may be provided in the contact hole.

[0075] The well region 11 is provided so as to overlap with the active side gate wiring 131. The well region 11 is also provided to extend with a predetermined width in a range not overlapping with the active side gate wiring 131. The well region 11 of this example is provided to be separated from the active side gate wiring 131 side relative to the end portion in the Y-axis direction of the contact hole 54. The well region 11 is a region of the second conductivity type having a higher doping concentration than the doping concentration of the base region 14. The base region 14 of this example is of P- type, and the well region 11 is of P+ type.

[0076] The transistor section 70 and the diode section 80 each have a plurality of groove sections arranged along the arrangement direction. In the transistor section 70 of this example, one or more gate groove sections 40 and one or more dummy groove sections 30 are alternately arranged along the arrangement direction. In the diode section 80 of this example, a plurality of dummy groove sections 30 are arranged along the arrangement direction. In the diode section 80 of this example, no gate groove section 40 is provided.

[0077] The gate trench portion 40 of this example may include two straight line portions 39 extending in an extending direction perpendicular to the arrangement direction (a portion forming a straight groove in the extending direction) and a front end portion 41 connecting the two straight line portions 39 . Figure 2 The extension direction is the Y-axis direction.

[0078] Preferably, at least a portion of the tip portion 41 is curved in a plan view. The tip portion 41 connects the ends of the two straight portions 39 in the Y-axis direction, thereby alleviating electric field concentration at the ends of the straight portions 39 .

[0079] In the transistor portion 70, the dummy trench portion 30 is provided between the straight line portions 39 of the gate trench portion 40. One dummy trench portion 30 may be provided between the straight line portions 39, or a plurality of dummy trench portions 30 may be provided. The dummy trench portion 30 may have a straight line shape extending in the extending direction, or may have a straight line portion 29 and a front end portion 31 similarly to the gate trench portion 40. Figure 2 The semiconductor device 100 shown includes both a linear dummy trench portion 30 having no front end portion 31 and a dummy trench portion 30 having a front end portion 31 .

[0080] The diffusion depth of the well region 11 may be deeper than the depth 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 in a plan view. 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. Thus, the electric field concentration at the bottom of each trench portion can be alleviated.

[0081] A mesa portion is provided between each groove portion in the arrangement direction. The mesa portion refers to an area clamped by the groove portion inside the semiconductor substrate 10. As an example, the upper end of the mesa portion is the upper surface of the semiconductor substrate 10. The depth position of the lower end of the mesa portion is the same as the depth position of the lower end of the groove portion. The mesa portion of this example is provided on the upper surface of the semiconductor substrate 10, extending along the groove in the extension direction (Y-axis direction). In this example, a mesa portion 60 is provided in the transistor portion 70, and a mesa portion 61 is provided in the diode portion 80. In this specification, when only the mesa portion is referred to, it refers to the mesa portion 60 and the mesa portion 61 in general.

[0082] A base region 14 is provided in each mesa portion. A region of the base region 14 exposed on the upper surface of the semiconductor substrate 10 in the mesa portion and arranged closest to the active-side gate wiring 131 is referred to as a base region 14-e. Figure 2 In the figure, although the base region 14-e is shown to be arranged at the end of one side in the extension direction of each mesa portion, the base region 14-e is also arranged at the end of the other side of each mesa portion. In each mesa portion, the area sandwiched by the base region 14-e in a plan view can be provided with at least one of the emitter region 12 of the first conductivity type and the contact region 15 of the second conductivity type. The emitter region 12 in this example is of N+ type, and the contact region 15 is of P+ type. The emitter region 12 and the contact region 15 can be arranged between the base region 14 and the upper surface of the semiconductor substrate 10 in the depth direction.

[0083] 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 provided 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.

[0084] The contact regions 15 and emitter regions 12 in the mesa portion 60 are arranged from one groove portion to the other groove portion in the X-axis direction. As an example, the contact regions 15 and emitter regions 12 of the mesa portion 60 are alternately arranged along the extending direction of the groove portion (Y-axis direction).

[0085] In other examples, the contact area 15 and the emitter area 12 of the mesa portion 60 may be arranged in strips along the extending direction of the groove portion (Y-axis direction). For example, the emitter area 12 is arranged in the area connected to the groove portion, and the contact area 15 is arranged in the area sandwiched by the emitter area 12.

[0086] The emitter region 12 is not provided in the mesa portion 61 of the diode portion 80. The base region 14 and the contact region 15 may be provided on the upper surface of the mesa portion 61. The contact region 15 may be provided in contact with each base region 14-e in the region sandwiched by the base region 14-e on the upper surface of the mesa portion 61. The base region 14 may be provided in the region sandwiched by the contact region 15 on the upper surface of the mesa portion 61. The base region 14 may be arranged in the entire region sandwiched by the contact region 15.

[0087] A contact hole 54 is provided above each mesa portion. The contact hole 54 is arranged in a region sandwiched by the base region 14-e. The contact hole 54 of this example is provided above each region of the contact region 15, the base region 14, and the emitter region 12. The contact hole 54 is not provided in a region corresponding to the base region 14-e and the well region 11. The contact hole 54 may be arranged in the center of the mesa portion 60 in the arrangement direction (X-axis direction).

[0088] In the diode portion 80, an N+ type cathode region 82 is provided in a region adjacent to the lower surface of the semiconductor substrate 10. In the lower surface of the semiconductor substrate 10, a P+ type collector region 22 may be provided in a region where the cathode region 82 is not provided. The cathode region 82 and the collector region 22 are provided between the lower surface 23 of the semiconductor substrate 10 and the buffer region 20. Figure 2 In FIG. 8 , a dotted line is used to indicate a boundary between the cathode region 82 and the collector region 22 .

[0089] The cathode region 82 is arranged to be separated from the well region 11 in the Y-axis direction. Thus, the distance between the P-type region (well region 11) formed to a deep position with a relatively high doping concentration and the cathode region 82 can be ensured, thereby improving the withstand voltage. The end of the cathode region 82 in the Y-axis direction of this example is arranged to be farther 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 can be arranged between the well region 11 and the contact hole 54.

[0090] Figure 3 It is shown Figure 2 ee cross section in FIG. The ee cross section is an XZ plane passing through the emitter region 12 and the cathode region 82. The semiconductor device 100 of this example includes the semiconductor substrate 10, the interlayer insulating film 38, the emitter electrode 52, and the collector electrode 24 in this cross section.

[0091] The interlayer insulating film 38 is provided on the upper surface of the semiconductor substrate 10. The interlayer insulating film 38 is a film including at least one of an insulating film such as silicate glass to which impurities such as boron or phosphorus are added, a thermal oxide film, and other insulating films. Figure 2 The contact hole 54 described in FIG.

[0092] The emitter electrode 52 is provided above the interlayer insulating film 38. The emitter electrode 52 contacts the upper surface 21 of the semiconductor substrate 10 through the contact hole 54 of the interlayer insulating film 38. The collector electrode 24 is provided on the lower surface 23 of the semiconductor substrate 10. The emitter electrode 52 and the collector electrode 24 are formed of a metal material such as aluminum. In this specification, the direction connecting the emitter electrode 52 and the collector electrode 24 (Z-axis direction) is referred to as the depth direction.

[0093] The semiconductor substrate 10 has an N-type or N-type drift region 18. The drift region 18 is provided in the transistor portion 70 and the diode portion 80, respectively.

[0094] In the mesa portion 60 of the transistor portion 70, an N+ type emitter region 12 and a P- type base region 14 are provided in order from the upper surface 21 side of the semiconductor substrate 10. A drift region 18 is provided below the base region 14. An N+ type accumulation region 16 may be provided in the mesa portion 60. The accumulation region 16 is arranged between the base region 14 and the drift region 18.

[0095] The emitter region 12 is exposed on the upper surface 21 of the semiconductor substrate 10 and is provided in contact with the gate trench portion 40. The emitter region 12 may be in contact with 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 drift region 18.

[0096] The base region 14 is provided below the emitter region 12. In this example, the base region 14 is provided in contact with the emitter region 12. The base region 14 may be in contact with the groove portions on both sides of the mesa portion 60.

[0097] The accumulation region 16 is provided below the base region 14. The accumulation region 16 is an N+ type region having a higher doping concentration than the drift region 18. That is, the donor concentration of the accumulation region 16 is higher than the donor concentration of the drift region 18. By providing a high-concentration accumulation region 16 between the drift region 18 and the base region 14, the carrier injection promotion effect (IE effect) can be improved and the on-state voltage can be reduced. The accumulation region 16 can be provided in a manner covering the entire lower surface of the base region 14 in each mesa portion 60.

[0098] The mesa portion 61 of the diode portion 80 is provided with a P-type base region 14 in contact with the upper surface 21 of the semiconductor substrate 10. The drift region 18 is provided below the base region 14. The reservoir region 16 may be provided below the base region 14 in the mesa portion 61.

[0099] In each transistor section 70 and each diode section 80, an N+ type buffer zone 20 may be provided below the drift region 18. The doping concentration of the buffer zone 20 is higher than the doping concentration of the drift region 18. The buffer zone 20 may have a concentration peak having a doping concentration higher than the doping concentration of the drift region 18. The doping concentration of the concentration peak refers to the doping concentration at the top of the concentration peak. In addition, the doping concentration of the drift region 18 may use the average value of the doping concentration in a region where the doping concentration distribution is substantially flat.

[0100] The buffer region 20 may have two or more concentration peaks in the depth direction (Z-axis direction) of the semiconductor substrate 10. The concentration peak of the buffer region 20 may be set at the same depth position as, for example, a chemical concentration peak of hydrogen (protons) or phosphorus. The buffer region 20 may function as a field stop layer that prevents the depletion layer extending from the lower end of the base region 14 from reaching the P+ type collector region 22 and the N+ type cathode region 82.

[0101] In the transistor portion 70, a P+ type collector region 22 is provided below the buffer region 20. The acceptor concentration of the collector region 22 is higher than the acceptor concentration of the base region 14. The collector region 22 may contain the same acceptor as the base region 14 or may contain an acceptor different from the base region 14. The acceptor of the collector region 22 is, for example, boron.

[0102] In the diode portion 80, an N+ type cathode region 82 is provided below the buffer region 20. The donor concentration of the cathode region 82 is higher than that of the drift region 18. The donor of the cathode region 82 is, for example, hydrogen or phosphorus. It should be noted that the elements that become the donors and acceptors of each region are not limited to the above examples. The collector region 22 and the cathode region 82 are exposed on the lower surface 23 of the semiconductor substrate 10 and are connected to the collector electrode 24. The collector electrode 24 may be in contact with the entire lower surface 23 of the semiconductor substrate 10. The emitter electrode 52 and the collector electrode 24 are formed of a metal material such as aluminum.

[0103] One or more gate groove portions 40 and one or more dummy groove portions 30 are provided on the upper surface 21 side of the semiconductor substrate 10. Each groove portion penetrates the base region 14 from the upper surface 21 of the semiconductor substrate 10 and is provided below the base region 14. In the region where at least any one of the emitter region 12, the contact region 15 and the accumulation region 16 is provided, each groove portion also penetrates these doped regions. The method of manufacturing in which the groove portion penetrates the doped region is not limited to the order of forming the groove portion after the doped region is formed. The method of forming the doped region between the groove portions after the groove portion is formed is also included in the method of the groove portion penetrating the doped region.

[0104] As described above, the transistor portion 70 is provided with the gate trench portion 40 and the dummy trench portion 30. The diode portion 80 is provided with the dummy trench portion 30, but no gate trench portion 40 is provided. In this example, the boundary between the diode portion 80 and the transistor portion 70 in the X-axis direction is the boundary between the cathode region 82 and the collector region 22.

[0105] The gate trench portion 40 includes a gate trench provided 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 provided to cover the inner wall of the gate trench. The gate insulating film 42 may be formed by oxidizing or nitriding the semiconductor of the inner wall of the gate trench. The gate conductive portion 44 is provided inside the gate trench at a position further inside 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.

[0106] The gate conductive portion 44 can be set longer than the base region 14 in the depth direction. The gate groove portion 40 in the cross section is covered by the 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 inversion layer of electrons is formed in the surface layer of the interface in the base region 14 that is connected to the gate groove portion 40.

[0107] The dummy groove portion 30 may have the same structure as the gate groove portion 40 in this cross section. The dummy groove portion 30 includes a dummy groove 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 is electrically connected to the emitter electrode 52. The dummy insulating film 32 is provided to cover the inner wall of the dummy groove. The dummy conductive portion 34 is provided inside the dummy groove and is provided at a position closer to the inner side 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 may 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.

[0108] The gate trench 40 and the dummy trench 30 of this example are covered by the interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10. The bottoms of the dummy trench 30 and the gate trench 40 may be curved surfaces convex downward (curved in cross section).

[0109] Figure 4 It is shown Figure 3 FIG. 1 is a diagram showing an example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line. The doping concentration can use the carrier concentration measured by the SR method or the like. The chemical concentrations of hydrogen, oxygen, and carbon can be measured by the SIMS method or the like. The ff line is a line parallel to the Z axis and passes through a portion of the buffer region 20 and the drift region 18. Figure 4 The horizontal axis in represents the depth position (position in the Z-axis direction) in the semiconductor substrate 10. In this specification, unless otherwise specified, the lower surface 23 of the semiconductor substrate 10 is set as the reference position (0) in the Z-axis direction, and the distance from the lower surface 23 is set as the position in the Z-axis direction.

[0110] A drift region 18 is provided above the buffer region 20. The doping concentration of the drift region 18 may be substantially constant. The doping concentration of the drift region 18 may be consistent with the body donor concentration BD, or may be higher than the body donor concentration BD. In this example, the doping concentration of the drift region 18 is consistent with the body donor concentration BD.

[0111] The body donor concentration BD may use the minimum value of the chemical concentration of the body donors in the semiconductor substrate 10, the chemical concentration of the body donors at the central position in the depth direction of the semiconductor substrate 10, or the average value of the chemical concentration of the body donors in the drift region 18. The body donor is a dopant other than oxygen and carbon, and is distributed throughout the semiconductor substrate 10. The body donor is, for example, phosphorus, but may also be arsenic, or antimony, and is not limited to these elements. In the case where both P-type body acceptors and N-type body donors are distributed throughout the semiconductor substrate 10, the body donor concentration BD is a net concentration determined by the difference between the concentration of the body donors and the concentration of the body acceptors. The concentrations of the body donors and the body acceptors may be values ​​measured by the SIMS method or the like.

[0112] The depth position of the boundary between the drift region 18 and the buffer region 20 is denoted as Zb. The depth position Zb in this example is a depth position at which the doping concentration first reaches the bulk donor concentration BD in the direction from the buffer region 20 toward the drift region 18 .

[0113] A buffer region 20 is provided between the drift region 18 and the lower surface 23. A collector region 22 is provided between the buffer region 20 and the lower surface 23. A boundary position Z0 between the collector region 22 and the buffer region 20 is a position of a PN junction between the collector region 22 and the buffer region 20.

[0114] The buffer region 20 in this example is a region containing hydrogen donors. In this specification, the buffer region 20 is an N-type region where hydrogen atoms (for example, chemical hydrogen concentration is greater than the detection limit) exist between the drift region 18 and the collector region 22 and the doping concentration is higher than the body donor concentration BD.

[0115] The buffer region 20 has more than one doping concentration peak 211 in the depth direction. Figure 4 In the example, the buffer region 20 is provided with a doping concentration peak 211-1, a doping concentration peak 211-2, a doping concentration peak 211-3, a doping concentration peak 211-4, and a doping concentration peak 211-5, starting from the peak close to the lower surface 23 of the semiconductor substrate 10. In this specification, the doping concentration peak 211-1 closest to the lower surface 23 is sometimes referred to as the shallowest doping concentration peak, and the doping concentration peak 211-5 farthest from the lower surface 23 is sometimes referred to as the deepest doping concentration peak.

[0116] The buffer zone 20 has one or more hydrogen peaks 221 in the depth direction. The hydrogen peak 221 is a peak of hydrogen chemical concentration. Figure 4In the example of , hydrogen peak 221-1, hydrogen peak 221-2, hydrogen peak 221-3, hydrogen peak 221-4, and hydrogen peak 221-5 are arranged in the buffer area 20 in order from the peak close to the lower surface 23 of the semiconductor substrate 10. In this specification, the hydrogen peak 221-1 closest to the lower surface 23 is sometimes referred to as the shallowest peak, and the hydrogen peak 221-5 farthest from the lower surface 23 is sometimes referred to as the deepest peak. It should be noted that the dopant of the doping concentration peak 211-1 closest to the lower surface 23 of the semiconductor substrate 10 can be phosphorus. In this case, the peak 211-1 becomes the phosphorus peak 211-1.

[0117] The depth position of the apex of the hydrogen peak 221-m (m is an integer greater than or equal to 1) is set to Zm. In this specification, the position of the apex of the peak is sometimes referred to as the position of the peak. In addition, the concentration at the apex of the peak is sometimes referred to as the concentration of the peak. The doping concentration peak 211-m can be configured at the same depth position Zm as the hydrogen peak 221-m. In the case where the depth position of the apex of one of the two peaks is included in the half-maximum width in the depth direction of the other peak, the two peaks can be configured at the same depth position.

[0118] The semiconductor substrate 10 has a lower region 201 and an upper region 202. The lower region 201 is a region extending from the lower surface 23 to the deepest peak (in this example, the hydrogen peak 221-5). The depth position of the upper end of the lower region 201 may be the depth position Z5 of the apex of the hydrogen peak 221-5, or may be the depth position (at the depth Z5) at which the hydrogen chemical concentration becomes below the detection lower limit on the upper surface 21 side from the apex of the hydrogen peak 221-5. Figure 4 In the example of FIG. 2 , the lower region 201 may be Zb), or may be the depth position Zb of the boundary between the buffer zone 20 and the drift zone 18. The upper end position of the lower region 201 in this example is Zb. The lower region 201 in this example includes the buffer zone 20, but in other examples, the lower region 201 may also be a region different from the buffer zone 20. In this case, the lower region 201 also includes one or more hydrogen peaks 221.

[0119] The upper region 202 is a region extending from the deepest peak (the hydrogen peak 221-5 in this example) to the upper surface 21. The upper region 202 is arranged at a position closer to the upper surface 21 than the lower region 201. The depth position of the lower end of the upper region 202 may be the same as the depth position of the upper end of the lower region 201, or may be different from the depth position of the upper end of the lower region 201. The depth position of the lower end of the upper region 202 in this example is Zb, which is the same as the depth position Zb of the upper end of the lower region 201. The upper region 202 may be the entire region from the depth position Zb to the upper surface 21, or may be a partial region from the depth position Zb to the upper surface 21. The upper region 202 in this example is a partial region from the depth position Zb to the upper surface 21. The upper end position Zu of the upper region 202 may be arranged in the drift region 18. The length of the upper region 202 in the depth direction (Zu-Zb in this example) may be the same as the length (Zb) of the lower region 201 in the depth direction, or may be smaller than the length (Zb) of the lower region 201 in the depth direction, or may be larger than the length (Zb) of the lower region 201 in the depth direction.

[0120] The carbon chemical concentration of the lower region 201 is set to Ca1, and the oxygen chemical concentration is set to Ox1. The carbon chemical concentration of the upper region 202 is set to Ca2, and the oxygen chemical concentration is set to Ox2. The carbon chemical concentration Ca1 and the oxygen chemical concentration Ox1 of the lower region 201 may use the average value of the carbon chemical concentration and the oxygen chemical concentration of the lower region 201, or the maximum value. The carbon chemical concentration Ca2 and the oxygen chemical concentration Ox2 of the upper region 202 may use the average value of the carbon chemical concentration and the oxygen chemical concentration of the upper region 202, or the maximum value.

[0121] Regarding at least one of the carbon chemical concentration and the oxygen chemical concentration, the concentration in the lower region 201 is at least twice the concentration in the upper region 202. Figure 4 In the example, the carbon chemical concentration Ca1 of the lower region 201 is more than twice the carbon chemical concentration Ca2 of the upper region 202 , and the oxygen chemical concentration OX1 of the lower region 201 is more than twice the oxygen chemical concentration Ox2 of the upper region 202 .

[0122] The carbon chemical concentration Ca1 can be 1×10 14 atoms / cm 3 The carbon chemical concentration Ca1 can be 5×10 14 atoms / cm 3 Above, it can also be 1×10 15 atoms / cm 3 Above, it can also be 5×10 15 atoms / cm 3Above, it can also be 1×10 16 atoms / cm 3 The oxygen chemical concentration Ox1 can be 2×10 17 atoms / cm 3 The oxygen chemical concentration Ox1 can be 3×10 17 atoms / cm 3 Above, it can also be 5×10 17 atoms / cm 3 above.

[0123] Carbon and oxygen are distributed roughly evenly on the semiconductor substrate 10 (semiconductor wafer) cut from the semiconductor ingot. Among them, the carbon chemical concentration and the oxygen chemical concentration vary between substrates. Sometimes hydrogen ions are injected into the semiconductor substrate 10 to form hydrogen donors, forming a high concentration area such as the buffer zone 20. The degree of hydrogen donor formation fluctuates according to the carbon chemical concentration and oxygen chemical concentration of the semiconductor substrate 10 relative to the dose of hydrogen ions. For example, the degree of VOH defect formation fluctuates according to the oxygen chemical concentration, and the degree of CiOi-H formation fluctuates according to the oxygen chemical concentration and the carbon chemical concentration. Therefore, the doping concentration of a high concentration area such as the buffer zone 20 fluctuates according to the carbon chemical concentration and the oxygen chemical concentration of the semiconductor substrate 10.

[0124] In the semiconductor device 100 of this example, at least one of carbon and oxygen is selectively implanted into the lower region 201 of the semiconductor substrate 10, thereby adjusting at least one of the carbon chemical concentration and the oxygen chemical concentration in the lower region 201. As a result, the influence of the deviation of the carbon chemical concentration and the oxygen chemical concentration of the semiconductor substrate 10 can be reduced, and the doping concentration in the lower region 201 (the buffer region 20 in this example) can be controlled with high accuracy.

[0125] For one or both of the carbon chemical concentration and the oxygen chemical concentration, the concentration of the lower region 201 may be more than 5 times the concentration of the upper region 202, or more than 10 times the concentration of the upper region 202. The dose of carbon and oxygen injected into the lower region 201 can be controlled with relatively high precision. Therefore, by injecting a large amount of carbon or oxygen into the lower region 201, the proportion of the deviation of the carbon chemical concentration and the oxygen chemical concentration in the semiconductor substrate 10 in the overall carbon chemical concentration and the oxygen chemical concentration can be reduced. For both the carbon chemical concentration and the oxygen chemical concentration, the concentration of the lower region 201 may be less than 1000 times the concentration of the upper region 202, or less than 100 times the concentration of the upper region 202, or less than 50 times the concentration of the upper region 202.

[0126] The lower region 201 of this example has a flat portion 231. In the flat portion 231, at least one of the chemical concentration of carbon and the chemical concentration of oxygen, which is twice or more the concentration in the upper region 202, is uniform. Figure 4 The flat portion 231 of the example has both uniform carbon chemical concentration and oxygen chemical concentration. In the flat portion 231, with respect to at least one of the carbon chemical concentration and the oxygen chemical concentration, the maximum concentration may be less than 1.1 times the minimum concentration, or less than 1.07 times the minimum concentration, or less than 1.05 times the minimum concentration. The length of the flat portion 231 in the depth direction may be more than 10% of the lower region 201, or more than 30% of the lower region 201, or more than 50% of the lower region 201, or more than 70% of the lower region 201, or more than 90% of the lower region 201, or 100% of the lower region 201. The length of the flat portion 231 in the depth direction may be more than 5 μm, or more than 10 μm, or more than 20 μm. By providing the flat portion 231, the hydrogen donor concentration of the lower region 201 can be controlled with high precision, and the doping concentration can be controlled with high precision.

[0127] Figure 5 It is shown Figure 3 ff line of the graph of another example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration and carbon chemical concentration. In this example, the distribution of carbon chemical concentration is Figure 4 The other distributions are different from Figure 4 Same as the example.

[0128] The carbon concentration of the lower region 201 in this example is less than twice the carbon concentration of the upper region 202. The carbon concentration of the lower region 201 may be less than 1.5 times the carbon concentration of the upper region 202, or may be the same as the carbon concentration of the upper region 202. In this example, oxygen is locally injected into the lower region 201, and carbon is not locally injected. By increasing the oxygen chemical concentration of the lower region 201, the deviation of the doping concentration caused by the deviation of the oxygen chemical concentration can be suppressed.

[0129] Figure 6 It is shown Figure 3 ff line of FIG. 1 is another example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration. In this example, the distribution of oxygen chemical concentration is Figure 4 The other distributions are different from Figure 4 Same as the example.

[0130] In this example, the oxygen concentration of the lower region 201 is less than twice the oxygen concentration of the upper region 202. The oxygen concentration of the lower region 201 may be less than 1.5 times the oxygen concentration of the upper region 202, or may be the same as the oxygen concentration of the upper region 202. In this example, carbon is locally injected into the lower region 201, and oxygen is not locally injected. By increasing the carbon chemical concentration of the lower region 201, the deviation of the doping concentration caused by the deviation of the carbon chemical concentration can be suppressed.

[0131] Figure 7 It is shown Figure 3 ff line of FIG. 1 is a graph showing another example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration. In this example, the distribution of at least one of the oxygen chemical concentration and the carbon chemical concentration is Figures 4 to 6 The other distributions are different from Figures 4 to 6 The same as any of the examples in Figure 7 In the Figures 4 to 6 However, one of the oxygen chemical concentration and the carbon chemical concentration may be different from Figures 4 to 6 The same as one of the examples in .

[0132] The lower region 201 of this example has one or more carbon peaks 242 as peaks of carbon chemical concentration in the depth direction. Figure 7 In the example, there is one carbon peak 242. The vertex position of the carbon peak 242 can be arranged near the center of the lower region 201 in the depth direction. The center vicinity can refer to the central region when the lower region 201 is divided into three equal parts along the depth direction. The half-maximum full width of the carbon peak 242 in the depth direction can be more than 50% of the length Zb of the lower region 201 in the depth direction, or more than 70% of the length Zb of the lower region 201 in the depth direction, or more than 90% of the length Zb of the lower region 201 in the depth direction, or more than 100% of the length Zb of the lower region 201 in the depth direction.

[0133] The carbon chemical concentration at the depth position Zb may be greater than the carbon chemical concentration Ca2 of the upper region 202. The carbon chemical concentration at the depth position Z0 may be greater than the carbon chemical concentration Ca2 of the upper region 202. The carbon chemical concentration at the vertex position Zm of each hydrogen peak 221-m may be greater than the carbon chemical concentration Ca2 of the upper region 202, and may be 1.5 times or more of the carbon chemical concentration Ca2 of the upper region 202, or may be 2 times or more of the carbon chemical concentration Ca2 of the upper region 202, or may be 5 times or more of the carbon chemical concentration Ca2 of the upper region 202, or may be 10 times or more of the carbon chemical concentration Ca2 of the upper region 202. The carbon chemical concentration Ca1 of the carbon peak 242 is 2 times or more of the carbon chemical concentration Ca2 of the upper region 202. The carbon chemical concentration Ca1 of the carbon peak 242 may be 5 times or more of the carbon chemical concentration Ca2 of the upper region 202, or may be 10 times or more of the carbon chemical concentration Ca2 of the upper region 202.

[0134] By accelerating carbon ions with relatively high acceleration energy and configuring an absorber on the carbon ion injection surface to adjust the range of carbon ions, it is possible to set Figure 7 The carbon peak 242 has a relatively large full width at half maximum as shown. According to this example, the variation in doping concentration caused by the variation in carbon chemical concentration can also be suppressed.

[0135] The lower region 201 of this example has one or more oxygen peaks 232 as peaks of oxygen chemical concentration in the depth direction. Figure 7 In the example, there is one oxygen peak 232. The apex position of the oxygen peak 232 can be arranged near the center in the depth direction of the lower region 201. The half-maximum width of the oxygen peak 232 in the depth direction can be more than 50% of the length Zb in the depth direction of the lower region 201, or more than 70% of the length Zb in the depth direction of the lower region 201, or more than 90% of the length Zb in the depth direction of the lower region 201, or more than 100% of the length Zb in the depth direction of the lower region 201.

[0136] The oxygen chemical concentration at the depth position Zb may be greater than the oxygen chemical concentration Ox2 of the upper region 202. The oxygen chemical concentration at the depth position Z0 may be greater than the oxygen chemical concentration Ox2 of the upper region 202. The oxygen chemical concentration at the vertex position Zm of each hydrogen peak 221-m may be greater than the oxygen chemical concentration Ox2 of the upper region 202, and may be 1.5 times or more of the oxygen chemical concentration Ox2 of the upper region 202, or may be 2 times or more of the oxygen chemical concentration Ox2 of the upper region 202, or may be 5 times or more of the oxygen chemical concentration Ox2 of the upper region 202, or may be 10 times or more of the oxygen chemical concentration Ox2 of the upper region 202. The oxygen chemical concentration Ox1 of the oxygen peak 232 is more than 2 times of the oxygen chemical concentration Ox2 of the upper region 202. The oxygen chemical concentration Ox1 of the oxygen peak 232 may be 5 times or more than the oxygen chemical concentration Ox2 of the upper region 202, or may be 10 times or more than the oxygen chemical concentration Ox2 of the upper region 202. According to this example, the variation in doping concentration caused by the variation in oxygen chemical concentration can also be suppressed.

[0137] Figure 8 It is shown Figure 3 ff line of FIG. 1 is a graph showing another example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration. In this example, the distribution of at least one of the oxygen chemical concentration and the carbon chemical concentration is Figures 4 to 7 The other distributions are different from Figures 4 to 7 The same as any of the examples in Figure 8 In the Figures 4 to 7 However, one of the oxygen chemical concentration and the carbon chemical concentration may be different from Figures 4 to 7 The same as one of the examples in .

[0138] The lower region 201 of this example has a plurality of carbon peaks 242 in the depth direction. In this example, at least one carbon peak 242 is arranged between two hydrogen peaks 221 in the depth direction. When the vertex of the carbon peak 242 is arranged in the central region obtained by dividing the region between the vertices of the two hydrogen peaks 221 into three equal parts along the depth direction, it can be regarded that the carbon peak 242 is arranged between the vertices of the two hydrogen peaks 221. In other examples, when the vertex of the carbon peak 242 is arranged between the vertices of the two hydrogen peaks 221 and the vertex of the carbon peak 242 is not arranged within the range of the half-maximum full width of the two hydrogen peaks 221, it can also be regarded that the carbon peak 242 is arranged between the vertices of the two hydrogen peaks 221.

[0139] All carbon peaks 242 may be arranged between two hydrogen peaks 221 in the depth direction. Carbon peak 242-m may be arranged between hydrogen peak 221-m and hydrogen peak 221-(m+1). In the depth direction, the number of carbon peaks 242 may be less than the number of hydrogen peaks 221.

[0140] By arranging the carbon peak 242 between the two hydrogen peaks 221, the depth position of the carbon ion implantation can be made different from the depth position of the hydrogen ion implantation. This can prevent the density of lattice defects formed by ion implantation from becoming locally too high.

[0141] The lower region 201 of this example has a plurality of oxygen peaks 232 in the depth direction. In this example, at least one oxygen peak 232 is arranged between two hydrogen peaks 221 in the depth direction. In the case where the apex of the oxygen peak 232 is arranged in the central region obtained by dividing the region between the apexes of the two hydrogen peaks 221 into three equal parts along the depth direction, it can be regarded that the oxygen peak 232 is arranged between the apexes of the two hydrogen peaks 221. In other examples, in the case where the apex of the oxygen peak 232 is arranged between the apexes of the two hydrogen peaks 221 and the apex of the oxygen peak 232 is not arranged within the range of the half-maximum full width of the two hydrogen peaks 221, it can also be regarded that the oxygen peak 232 is arranged between the apexes of the two hydrogen peaks 221.

[0142] All oxygen peaks 232 may be arranged between two hydrogen peaks 221 in the depth direction. Oxygen peak 232-m may be arranged between hydrogen peak 221-m and hydrogen peak 221-(m+1). In the depth direction, the number of oxygen peaks 232 may be less than the number of hydrogen peaks 221.

[0143] By arranging the oxygen peak 232 between the two hydrogen peaks 221, the depth position of oxygen ion implantation can be made different from the depth position of hydrogen ion implantation. This can prevent the density of lattice defects formed by ion implantation from becoming excessively high locally.

[0144] Fig. 9 2 is a diagram showing an example of the relative positions of the oxygen peak 232 and the carbon peak 242. The lower region 201 of this example has one or more carbon peaks 242 and one or more oxygen peaks 232 in the depth direction. In addition, at least one carbon peak 242 and at least one oxygen peak 232 are arranged at the same depth position. Fig. 9 In the example of FIG. 1 , an example is shown in which the oxygen peak 232-2 and the carbon peak 242-2 are arranged at the same depth position, but other oxygen peaks 232-m and carbon peaks 242-m may also be arranged at the same depth position. In this example, the apex of the carbon peak 242-2 is arranged within the range of the half-maximum full width FWHM of the oxygen peak 232-2. In other examples, the apex of the oxygen peak 232-2 may also be arranged within the range of the half-maximum full width FWHM of the carbon peak 242-2.

[0145] If the oxygen peak 232 and the carbon peak 242 are arranged at the same depth position, both the oxygen chemical concentration and the carbon chemical concentration near the position are increased. Therefore, the concentration of hydrogen donors such as CiOi-H near the position is stabilized, and the deviation of the doping concentration can be suppressed.

[0146] Hydrogen donors such as CiOi-H are easily formed near the apex of the oxygen peak 232-2 and the carbon peak 242-2. Therefore, a second doping concentration peak 213 is sometimes formed at a depth position of the apex of the oxygen peak 232-2 and the carbon peak 242-2. Fig. 9 As shown, when the oxygen peak 232-2 and the carbon peak 242-2 are arranged between the two hydrogen peaks 221-2 and 221-3, the second doping concentration peak 213 can be arranged between the two doping concentration peaks 211-2 and 211-3. The doping concentration peak 211 in this example is an example of the first doping concentration peak.

[0147] The doping concentration of the second doping concentration peak 213 is set to D3. The doping concentration of the doping concentration peak 211-2 adjacent to the second doping concentration peak 213 in the depth direction is set to D12, and the doping concentration of the doping concentration peak 211-3 is set to D13. The doping concentration D3 may be smaller than either the doping concentration D12 or the doping concentration D13. The doping concentration D3 may be less than 50% or less than 30% relative to either the doping concentration D12 or the doping concentration D13. The doping concentration D3 may be more than 1% or more than 10% relative to either the doping concentration D12 or the doping concentration D13. According to this example, the doping concentration distribution between the doping concentration peaks 211 can be flattened.

[0148] Fig.10 2 is a diagram showing another example of the relative positions of the oxygen peak 232 and the carbon peak 242. The lower region 201 of this example has one or more carbon peaks 242 and one or more oxygen peaks 232 in the depth direction. In addition, at least one carbon peak 242 is configured at a depth position different from any oxygen peak 232. In addition, at least one oxygen peak 232 is configured at a depth position different from any carbon peak 242. Fig.10 In the example of FIG. 1 , an example is shown in which the oxygen peak 232-2 and the carbon peak 242-2 are not arranged at the same depth position, but the other oxygen peaks 232-m and the carbon peaks 242-m may not be arranged at the same depth position. In other examples, some of the oxygen peaks 232-m and the carbon peaks 242-m in the combination of the oxygen peak 232-m and the carbon peak 242-m may be arranged at the same depth position, and the other oxygen peaks 232-m and the carbon peaks 242-m may not be arranged at the same depth position.

[0149] In this example, the apex of the carbon peak 242-2 is arranged outside the range of the full width at half maximum FWHM of the oxygen peak 232-2. In addition, the apex of the oxygen peak 232-2 is arranged outside the range of the full width at half maximum FWHM of the carbon peak 242-2. According to this example, it is possible to suppress the situation where the density of lattice defects formed by oxygen ion implantation and carbon ion implantation becomes excessively high locally.

[0150] Fig.11 It is shown Figure 3 FIG. 1 is another example of the distribution of the doping concentration, hydrogen chemical concentration, oxygen chemical concentration, and carbon chemical concentration at the ff line. In this example, the upper region 202 has at least one of one or more carbon peaks 242 and one or more oxygen peaks 232. Fig.11 The upper region 202 is shown to have a carbon peak 242-5 and an oxygen peak 232-5.

[0151] The carbon peak 242-4 and the oxygen peak 232-5 are arranged at a position closer to the upper surface 21 than the hydrogen peak 221-5. The carbon peak 242-5 can be arranged near the carbon peak 242-4. The carbon peak 242-5 can be arranged in a manner that the minimum value Ca3 of the carbon chemical concentration between the carbon peak 242-4 and the carbon peak 242-5 is greater than the carbon chemical concentration Ca2 of the upper region 202. The carbon chemical concentration Ca3 can be more than twice the carbon chemical concentration Ca2. According to this example, the carbon chemical concentration can also be increased near the depth position Zb. Therefore, the doping concentration of the buffer zone 20 near the depth position Zb can be stabilized.

[0152] The oxygen peak 232-5 can be arranged near the oxygen peak 232-4. The oxygen peak 232-5 can be arranged in such a way that the minimum value Ox3 of the oxygen chemical concentration between the oxygen peak 232-4 and the oxygen peak 232-5 is greater than the oxygen chemical concentration Ox2 of the upper region 202. The oxygen chemical concentration Ox3 can be more than twice the oxygen chemical concentration Ox2. According to this example, the oxygen chemical concentration can also be increased near the depth position Zb. Therefore, the doping concentration of the buffer region 20 near the depth position Zb can be stabilized.

[0153] The doping concentration distribution of this example has a plurality of second doping concentration peaks 213. A second doping concentration peak 213 is arranged between each of the two hydrogen peaks 221. The carbon peak 242-4 and the oxygen peak 232-5 can be arranged at the same depth position. In this case, the second doping concentration peak 213-5 can be arranged at a position closer to the upper surface 21 than the doping concentration peak 211-5. Thus, the fluctuation of the doping concentration near the depth position Zb can be smoothed. Therefore, when the semiconductor device 100 is turned off, etc., the vibration of the emitter-collector voltage when the space charge region (depletion layer) extending from the boundary between the drift region 18 and the base region 14 reaches the vicinity of the depth position Zb can be suppressed.

[0154] Fig.12 It is shown Figure 3 1 is a diagram showing another example of the distribution of the oxygen chemical concentration and the carbon chemical concentration at the ff line. In this example, the lower region 201 has more peaks than the hydrogen peak 221 in at least one of the oxygen chemical concentration and the carbon chemical concentration. Fig.12The lower region 201 shown in FIG. 1 has more peaks than the hydrogen peak 221 in both the oxygen chemical concentration and the carbon chemical concentration. By changing the acceleration energy of the ions implanted into the semiconductor substrate 10 in stages, a plurality of concentration peaks can be formed. According to this example, at least one of the oxygen chemical concentration and the carbon chemical concentration in the lower region 201 can be flattened. By increasing the density of the peaks in the depth direction, a peak density can be formed. Figure 4 A flat portion 231 as shown.

[0155] Fig.13 FIG. 1 is a diagram showing a part of the steps of the method for manufacturing the semiconductor device 100. Fig.13 , an adjustment step S1200 is shown in which at least one of carbon, oxygen, and silicon is implanted into the lower region 201 and annealed. The concentration adjustment step S1200 is included in the manufacturing process of the semiconductor device 100. The concentration adjustment step S1200 is performed before the step of implanting hydrogen ions into the lower region 201.

[0156] The adjustment step S1200 includes an ion implantation step S1201 and an annealing step S1202. In the ion implantation step S1201, at least one of carbon, oxygen, and silicon is implanted into the region where the lower region 201 is to be formed. Figures 1 to 12 In the example of , at least one of carbon and oxygen is implanted into the lower region 201, but the concentration of hydrogen donors formed in the lower region 201 can also be adjusted by implanting silicon into the lower region 201. In the ion implantation step S1201, at least one of the carbon concentration and the oxygen concentration in the semiconductor substrate 10 can be measured, and the dose of at least one of carbon and oxygen can be adjusted based on the measurement result. In the ion implantation step S1201, the dose of at least one of carbon and oxygen can be adjusted based on the difference between at least one of the carbon concentration and the oxygen concentration in the semiconductor substrate 10 and a preset reference value.

[0157] In the annealing step S1202, the semiconductor substrate 10 is annealed by furnace annealing or the like. The annealing temperature in the annealing step S1202 is above 700°C. The annealing temperature in the annealing step S1202 may be above 750°C or above 800°C. By annealing at a relatively high temperature, the carbon and the like injected into the lower region 201 can be diffused, and the distribution of the carbon and the like in the lower region 201 can be made uniform. After the annealing step S1202, hydrogen ions are injected into the lower region 201 to form the buffer region 20. Since the concentration of carbon and the like in the lower region 201 is adjusted, the doping concentration in the lower region 201 can be controlled with high precision.

[0158] Fig.14 FIG. 1 is a diagram showing an overview of a method for manufacturing a semiconductor device 100. The method for manufacturing a semiconductor device 100 may include steps other than Fig.14The steps other than those shown may not have Fig.14 A portion of the process is shown.

[0159] In the manufacturing method of this example, in the upper surface side structure forming step S1302, a structure is formed on the upper surface 21 side of the semiconductor substrate 10. The structure on the upper surface 21 side is, for example, a structure on the upper side than the center in the depth direction of the semiconductor substrate 10. The structure on the upper surface 21 side includes the emitter region 12, the base region 14, the groove portion, the insulating film, the gate wiring, the gate pad 164, and at least a portion of the emitter electrode 52.

[0160] Next, in the protective film forming step S1304, a protective film is formed to cover at least a portion of the emitter electrode 52, the gate pad 164, and the gate wiring. The protective film is, for example, a polyimide film. The protective film may cover the emitter electrode 52, the gate pad 164, and the gate wiring where no wiring such as a wire or a lead frame is connected.

[0161] Next, in the substrate thinning step S1306, the lower surface of the semiconductor substrate 10 is ground to thin the semiconductor substrate 10. In the substrate thinning step S1306, the semiconductor substrate 10 can be thinned according to the withstand voltage that the semiconductor device 100 should have. In the substrate thinning step S1306, the semiconductor substrate 10 can be ground by a CMP method or the like.

[0162] Next, in the lower surface etching step S1308, the lower surface of the semiconductor substrate 10 is etched to remove the region damaged in the substrate thinning step S1306.

[0163] Next, in the lower surface ion implantation step S1310, dopant ions are implanted into the lower surface 23 of the semiconductor substrate 10. In the lower surface ion implantation step S1310, dopant ions are implanted into the region where the collector region 22 and the cathode region 82 are to be formed. Next, in the annealing step S1312, laser annealing is performed on the collector region 22 and the cathode region 82 to activate the dopant.

[0164] Next, in the hydrogen ion implantation step S1314, hydrogen ions are implanted from the lower surface 23 into the region where the buffer region 20 is to be formed. In the hydrogen ion implantation step S1314, hydrogen ions are implanted into a depth position where one or more hydrogen peaks 221 are to be formed.

[0165] Before the hydrogen ion implantation step S1314, a resist may be formed on the lower surface 23. The range of hydrogen ions may be adjusted by the resist. Next, in the resist removal step S1316, the resist on the lower surface 23 is removed. Next, in the annealing step S1318, the semiconductor substrate 10 is annealed by furnace annealing or the like. Thus, hydrogen donors are formed, thereby forming the buffer region 20. The annealing temperature in the annealing step S1318 is below 400°C. The annealing temperature in the annealing step S1318 may be below 390°C, or below 380°C. Next, in the lower surface electrode formation step S1320, a collector electrode 24 is formed. The collector electrode 24 may be formed by sputtering or the like.

[0166] like Fig.14 As shown, the adjustment step S1200 is performed at any time before the hydrogen ion implantation step S1314. By performing the relatively high temperature annealing step S1202 before the hydrogen ion implantation step S1314, the disappearance of hydrogen donors due to the high temperature annealing can be suppressed.

[0167] The adjustment step S1200 may be performed before the upper surface side structure forming step S1302, before the protective film forming step S1304, or before the substrate thinning step S1306. When the adjustment step S1200 is performed before the substrate thinning step S1306, carbon, oxygen, and silicon ions may be injected from the upper surface 21 of the semiconductor substrate 10. When the adjustment step S1200 is performed after the substrate thinning step S1306, carbon, oxygen, and silicon ions may be injected from the lower surface 23 of the semiconductor substrate 10.

[0168] The adjustment step S1200 may be performed before the lower surface etching step S1308, or before the lower surface ion implantation step S1310, or before the annealing step S1312. The process after the adjustment step S1200 may be performed at a temperature below 400°C. The process after the adjustment step S1200 may be performed at a temperature below 390°C, or at a temperature below 380°C.

[0169] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. According to the description of the claims, the method to which such changes or improvements are made can also be included in the technical scope of the present invention.

[0170] It should be noted that the execution order of each process such as actions, sequences, steps and stages in the apparatus, system, program and method shown in the claims, specifications and drawings can be implemented in any order unless it is specifically stated "before...", "in advance", etc., and the result of the previous process is not used in the subsequent process. Even if the action flow in the claims, specifications and drawings is described using "first", "next", etc. for convenience, it does not mean that it must be implemented in this order.

Claims

1. A semiconductor device, characterized in that: A semiconductor substrate is provided, wherein the semiconductor substrate has an upper surface and a lower surface, The semiconductor substrate has one or more hydrogen peaks as peaks of hydrogen chemical concentration in a depth direction, the one or more hydrogen peaks including a deepest peak farthest from the lower surface of the semiconductor substrate, The semiconductor substrate includes: a lower region which is a region extending from the lower surface to the deepest peak; and an upper region which is a region extending from the deepest peak to the upper surface. With respect to at least one of a carbon chemical concentration and an oxygen chemical concentration, a concentration in the lower region is at least twice a concentration in the upper region.

2. The semiconductor device according to claim 1, wherein: The semiconductor substrate has: A drift region of a first conductivity type; and a buffer zone of the first conductivity type, which is disposed between the lower surface and the drift region and has a doping concentration higher than that of the drift region, The deepest peak is arranged in the buffer zone.

3. The semiconductor device according to claim 1, wherein: The lower region has a flat portion where at least one of the carbon chemical concentration and the oxygen chemical concentration is uniform.

4. The semiconductor device according to claim 1, wherein: The lower region has one or more carbon peaks as peaks of the carbon chemical concentration in the depth direction.

5. The semiconductor device according to claim 4, wherein: The lower region has a plurality of the carbon peaks in the depth direction.

6. The semiconductor device according to claim 4, wherein: The lower region has a plurality of hydrogen peaks in the depth direction, At least one of the carbon peaks is arranged between two of the hydrogen peaks in the depth direction.

7. The semiconductor device according to claim 4, wherein: The upper region has one or more carbon peaks.

8. The semiconductor device according to claim 1, wherein: The lower region has one or more oxygen peaks as peaks of the oxygen chemical concentration in the depth direction.

9. The semiconductor device according to claim 8, wherein: The lower region has a plurality of oxygen peaks in the depth direction.

10. The semiconductor device according to claim 8, wherein: The lower region has a plurality of hydrogen peaks in the depth direction, At least one of the oxygen peaks is arranged between the two hydrogen peaks in the depth direction.

11. The semiconductor device according to claim 8, wherein: The upper region has one or more oxygen peaks.

12. The semiconductor device according to claim 1, wherein: The lower region has one or more carbon peaks as peaks of the carbon chemical concentration and one or more oxygen peaks as peaks of the oxygen chemical concentration in the depth direction.

13. The semiconductor device according to claim 12, wherein: At least one of the carbon peaks and at least one of the oxygen peaks are arranged at the same depth position.

14. The semiconductor device according to claim 13, wherein: The lower region has a plurality of doping concentration peaks in the depth direction, The multiple doping concentration peaks have: a plurality of first doping concentration peaks corresponding to the plurality of hydrogen peaks; and The second doping concentration peak is arranged between the two hydrogen peaks.

15. The semiconductor device according to claim 12, wherein: At least one of the carbon peaks is arranged at a depth position different from that of any of the oxygen peaks.

16. The semiconductor device according to any one of claims 1 to 15, characterized in that The carbon chemical concentration in the lower region is 1×10 14 atoms / cm 3 above.

17. The semiconductor device according to any one of claims 1 to 15, characterized in that The oxygen chemical concentration in the lower area is 2×10 17 atoms / cm 3 above.

18. A method for manufacturing a semiconductor device, characterized in that: The semiconductor device includes a semiconductor substrate having an upper surface and a lower surface. The semiconductor substrate has one or more hydrogen peaks as peaks of hydrogen chemical concentration in a depth direction, the one or more hydrogen peaks including a deepest peak farthest from the lower surface of the semiconductor substrate, The semiconductor substrate includes: a lower region which is a region extending from the lower surface to the deepest peak; and an upper region which is a region extending from the deepest peak to the upper surface. The manufacturing method: injecting at least one of carbon, oxygen and silicon into the region where the lower region is to be formed; Annealing the semiconductor substrate at a temperature above 700° C.; as well as Hydrogen ions are implanted into the depth position where one or more hydrogen peaks should be formed.

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