Semiconductor device and method for manufacturing semiconductor device

Abstract

To suppress unevenness in the breakdown voltage of semiconductor devices.SOLUTION: Provided is a semiconductor device comprising a semiconductor substrate having a bulk doping region, an active part, and an edge termination structural part. The edge termination structural part has a first high concentration region of a first conductive type, the donor concentration of which is higher than the doping concentration of the bulk donor, the first high concentration region having a hydrogen peak part, and a second high concentration region of the first conductive type, in which the donor concentration in at least a partial region of the edge termination structural part including a section in contact with the active part, from the depth position of the hydrogen peak part to the underside of the semiconductor substrate, is higher than the doping concentration of the bulk donor, and the doping concentration is higher than that in the bulk doping region. A guard ring of a second conductive type is provided on the upper side of the semiconductor substrate of the edge termination structural part, and a well region is provided. The second high concentration region is adjacent closer to an end part side of the semiconductor substrate than the well region or the one or more guard rings.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Conventionally, a structure has been known in which a P-type guard ring is provided around the periphery of an N-type semiconductor substrate on which semiconductor elements such as IGBTs (insulated gate bipolar transistors) are formed, thereby improving the breakdown voltage (see, for example, Patent Document 1). Patent Document 1: Japanese Patent Application Laid-Open No. 8-167715 Summary of the Invention [Problem to be solved by the invention]

[0003] It is preferable that the semiconductor device has small variations in withstand voltage. [Means for solving the problem]

[0004] In order to achieve the above object, in a first aspect of the present invention, there is provided a semiconductor substrate having a bulk doped region of a first conductivity type in which bulk donors of a first conductivity type are distributed throughout and in which a doping concentration is the concentration of the bulk donor, an active portion provided in the semiconductor substrate, and an edge termination structure provided in the semiconductor substrate and disposed on an upper surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate, the edge termination structure having a first high concentration region of a first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the first high concentration region having a donor concentration higher than the doping concentration of the bulk donor, the upper surface of the first high concentration region being located on the upper surface side of the semiconductor substrate and the lower surface of the first high concentration region being located on the lower surface side of the semiconductor substrate, the first high concentration region being disposed on the upper surface side of the semiconductor substrate, the edge termination structure has a hydrogen peak portion where a hydrogen concentration peaks in at least a portion of the edge termination structure including a portion in contact with the active portion, a donor concentration from a depth position of the hydrogen peak portion to an underside of the semiconductor substrate is higher than a doping concentration of the bulk donor, the edge termination structure has a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region, the doping concentration of the bulk doped region being higher than that of the bulk doped region, and the edge termination structure has a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure having a doping concentration higher than that of the bulk donor, and the edge termination structure has a well region of a second conductivity type between the edge termination structure and the active portion, and the second high concentration region is adjacent to an edge side of the semiconductor substrate relative to the well region or one or more of the guard rings.

[0005] In order to achieve the above object, in a second aspect of the present invention, there is provided a semiconductor substrate having a bulk doped region of a first conductivity type, the bulk donor being distributed throughout the semiconductor substrate and having a doping concentration equal to the concentration of the bulk donor; an active portion provided in the semiconductor substrate; and an edge termination structure provided in the semiconductor substrate and disposed on an upper surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate, the edge termination structure having a first high concentration region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the first high concentration region having a donor concentration higher than the doping concentration of the bulk donor, the upper surface of the first high concentration region being located on the upper surface side of the semiconductor substrate, the lower surface of the concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region has a flat portion with a uniform carrier concentration in the depth direction, a second high concentration region of a first conductivity type having a doping concentration higher than that of the bulk doping region is provided on the upper surface side of the semiconductor substrate of the bulk doping region of the edge termination structure, a guard ring of a second conductivity type having a doping concentration higher than the doping concentration of the bulk donor is provided on the upper surface side of the semiconductor substrate of the edge termination structure, and a well region of a second conductivity type is provided between the edge termination structure and the active portion, and the second high concentration region is adjacent to the well region or one or more of the guard rings towards the edge of the semiconductor substrate.

[0006] In order to achieve the above object, in a third aspect of the present invention, there is provided a semiconductor substrate having a bulk doped region of a first conductivity type, the bulk donor being distributed throughout the semiconductor substrate and having a doping concentration equal to the concentration of the bulk donor; an active portion provided in the semiconductor substrate; and an edge termination structure provided in the semiconductor substrate and disposed on an upper surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate, the edge termination structure having a first highly doped region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the first highly doped region having a donor concentration higher than the doping concentration of the bulk donor, the upper surface of the first highly doped region being located on the upper surface side of the semiconductor substrate and the lower surface of the first highly doped region being located on the lower surface side of the semiconductor substrate, the first highly doped region being disposed on the upper surface side of the semiconductor substrate and having a depth direction the edge termination structure has a hydrogen peak portion where hydrogen concentration peaks in a hydrogen concentration distribution in a depth direction, the first high concentration region on the upper surface side of the hydrogen peak portion has a smaller width in the depth direction than the first high concentration region on the lower surface side of the hydrogen peak portion, the edge termination structure has a second high concentration region of a first conductivity type on the upper surface side of the semiconductor substrate of the bulk doped region, the edge termination structure has a guard ring of a second conductivity type on the upper surface side of the semiconductor substrate of the edge termination structure and has a doping concentration higher than that of the bulk donor, and the edge termination structure has a well region of a second conductivity type between the edge termination structure and the active portion, and the second high concentration region is adjacent to the well region or one or more of the guard rings on the edge side of the semiconductor substrate.

[0007] In order to achieve the above object, in a fourth aspect of the present invention, there is provided a semiconductor substrate having a bulk doped region of a first conductivity type, the bulk donor being distributed throughout the semiconductor substrate and having a doping concentration equal to the concentration of the bulk donor; an active portion provided in the semiconductor substrate; and an edge termination structure provided in the semiconductor substrate and disposed on an upper surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate, the edge termination structure having a first highly doped region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the first highly doped region having a donor concentration higher than the doping concentration of the bulk donor, the upper surface of the first highly doped region being located on the upper surface side of the semiconductor substrate and the lower surface of the first highly doped region being located on the lower surface side of the semiconductor substrate, the first highly doped region being disposed on the upper surface side of the semiconductor substrate and having a deep the edge termination structure includes a second high concentration region of a first conductivity type having a doping concentration higher than that of the bulk doping region, on the upper surface side of the semiconductor substrate in the bulk doping region of the edge termination structure; the edge termination structure includes a guard ring of a second conductivity type having a doping concentration higher than that of the bulk donor, on the upper surface side of the semiconductor substrate in the edge termination structure; and the edge termination structure includes a well region of a second conductivity type between the edge termination structure and the active portion, and the second high concentration region is adjacent to the well region or one or more of the guard rings on the edge side of the semiconductor substrate.

[0008] In order to achieve the above object, in a fifth aspect of the present invention, there is provided a semiconductor substrate having a bulk doped region of a first conductivity type, the bulk donor being distributed throughout the semiconductor substrate and having a doping concentration equal to the concentration of the bulk donor; an active portion provided in the semiconductor substrate; and an edge termination structure provided in the semiconductor substrate and disposed on an upper surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate, the edge termination structure having a first high concentration region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the first high concentration region having a donor concentration higher than the doping concentration of the bulk donor, the upper surface of the first high concentration region being located on the upper surface side of the semiconductor substrate, the lower surface of the concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region has a depth length that gradually increases away from the active portion, the edge termination structure has a bulk doped region of a first conductivity type on the upper surface side of the semiconductor substrate, the bulk doped region of the edge termination structure has a guard ring of a second conductivity type on the upper surface side of the semiconductor substrate of the edge termination structure, the guard ring has a doping concentration of a second conductivity type higher than the doping concentration of the bulk donor, and the edge termination structure has a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or one or more of the guard rings on the edge side of the semiconductor substrate.

[0009] In order to achieve the above object, a sixth aspect of the present invention provides a semiconductor substrate having a first conductivity type bulk donor distributed throughout, an active portion provided in the semiconductor substrate, and an edge termination structure provided in the semiconductor substrate and disposed on an upper surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate, the edge termination structure having a first high concentration region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the first high concentration region having a donor concentration higher than a doping concentration of the bulk donor, the upper surface of the first high concentration region being adjacent to an upper surface of the semiconductor substrate. the active portion has a fourth high concentration region of a first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the fourth high concentration region having a donor concentration higher than a doping concentration of the bulk donor and in contact with at least the first high concentration region, the upper surface of the fourth high concentration region being located on the upper surface side of the semiconductor substrate, the lower surface of the fourth high concentration region being located on the lower surface side of the semiconductor substrate, and the upper end position of the fourth high concentration region being located on the lower surface side of the semiconductor substrate.

[0010] In any of the above semiconductor devices, the semiconductor substrate may have a bulk doped region of a first conductivity type having a doping concentration equal to the concentration of the bulk donor, a second high concentration region of the first conductivity type having a doping concentration higher than that of the bulk doped region on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, a guard ring of the second conductivity type having a doping concentration higher than the doping concentration of the bulk donor on an upper surface side of the semiconductor substrate of the edge termination structure, and a well region of the second conductivity type between the edge termination structure and the active portion, and the second high concentration region may be adjacent to an edge side of the semiconductor substrate from the well region or one or more of the guard rings.

[0011] In any of the semiconductor devices described above, the first high concentration region may be disposed on an upper surface side of the semiconductor substrate, and may have a hydrogen peak portion where the hydrogen concentration exhibits a peak in a hydrogen concentration distribution in the depth direction.

[0012] In any of the above semiconductor devices, the hydrogen peak portion may contain helium.

[0013] In any of the semiconductor devices described above, the edge termination structure may include a plurality of the guard rings.

[0014] In any of the semiconductor devices described above, the second high concentration region may be provided between two of the guard rings adjacent to each other.

[0015] In any of the above semiconductor devices, the hydrogen peak portion may be disposed below the second high concentration region.

[0016] In any of the above semiconductor devices, the hydrogen peak portion may be disposed between a lower end of the guard ring and the lower surface of the semiconductor substrate.

[0017] In any of the above semiconductor devices, the first high concentration region may be in contact with the guard ring.

[0018] In any of the above semiconductor devices, the active portion may have a base region of a second conductivity type arranged on an upper surface side of the semiconductor substrate, and the distance in the depth direction between the hydrogen peak portion and the second high concentration region may be smaller than the maximum distance between the well region and each point of the guard ring closest to the well region.

[0019] In any of the above semiconductor devices, the second high concentration region contains hydrogen implanted from the upper surface of the semiconductor substrate, and the hydrogen peak portion contains hydrogen implanted from the lower surface of the semiconductor substrate, and a hydrogen concentration distribution in the depth direction of the second high concentration region has a first peak indicating a peak in hydrogen concentration, and the first peak and the hydrogen peak portion may overlap.

[0020] In any of the above semiconductor devices, the second high concentration region contains hydrogen implanted from the upper surface of the semiconductor substrate, the hydrogen peak portion contains hydrogen implanted from the lower surface of the semiconductor substrate, a hydrogen concentration distribution in the depth direction of the second high concentration region has a first peak indicating a peak in hydrogen concentration, and the hydrogen peak portion may be located between the first peak and the upper surface of the semiconductor substrate.

[0021] In any of the semiconductor devices described above, the second high concentration region may contain a hydrogen donor.

[0022] In any of the semiconductor devices described above, the second high concentration region may be provided between two adjacent guard rings, from a position shallower than the bottom ends of the guard rings to a position deeper than the bottom ends of the guard rings.

[0023] In any of the semiconductor devices described above, the second high concentration region may be in contact with the upper surface of the semiconductor substrate.

[0024] In any of the above semiconductor devices, the first high concentration region may have a hydrogen donor.

[0025] In any of the above semiconductor devices, the bulk donor may be phosphorus or antimony.

[0026] In any of the semiconductor devices described above, the first high concentration region may be provided in a range that does not reach the active portion.

[0027] In any of the semiconductor devices described above, the first high concentration region may have an inner portion and an outer portion that is provided outside the inner portion and has a length in a depth direction of the semiconductor substrate greater than that of the inner portion.

[0028] In any of the above semiconductor devices, the semiconductor substrate may have a bulk acceptor of the second conductivity type distributed throughout.

[0029] In any of the above semiconductor devices, the bulk acceptor may be boron.

[0030] In any one of the above semiconductor devices, the dose of the donor in the second high concentration region is 5×10 11 / cm 2 It may be the following:

[0031] In any one of the above semiconductor devices, the dose of the donor in the second high concentration region is 1×10 11 / cm 2 It may be more than that.

[0032] In any of the above semiconductor devices, a peak value of the donor concentration in the second high concentration region may be ten times or more the minimum value of the donor concentration in the first high concentration region.

[0033] In any of the above semiconductor devices, the distance between a bottom end of the second high concentration region and an top end of the first high concentration region may be 50 μm or less.

[0034] In any of the above semiconductor devices, the distance between a bottom end of the second high concentration region and an top end of the first high concentration region may be 15 μm or more.

[0035] In any of the semiconductor devices described above, a depth position of a lower end of the second heavily doped region may be 2 μm or more away from an upper surface of the semiconductor substrate.

[0036] In any of the above semiconductor devices, the active portion may have a fourth high concentration region of a first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the fourth high concentration region having a donor concentration higher than a doping concentration of the bulk donor, the upper surface of the fourth high concentration region being located on the upper surface side of the semiconductor substrate and the lower surface of the fourth high concentration region being located on the lower surface side of the semiconductor substrate, and the donor concentration of the fourth high concentration region may be different from the donor concentration of the first high concentration region.

[0037] In any of the above semiconductor devices, the active portion may have a fourth high concentration region of a first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the fourth high concentration region having a donor concentration higher than a doping concentration of the bulk donor, an upper surface of the fourth high concentration region being located on the upper surface side of the semiconductor substrate, a lower surface of the fourth high concentration region being located on the lower surface side of the semiconductor substrate, and an upper end position of the fourth high concentration region being different from an upper end position of the first high concentration region.

[0038] In any one of the above semiconductor devices, in the edge termination structure, the first high concentration region and the second high concentration region may be provided contiguously.

[0039] In any of the above semiconductor devices, the second high concentration region may be provided between two of the guard rings adjacent to each other. In any of the above semiconductor devices, the edge termination structure may have a plurality of the guard rings, and at least a portion of the region including a portion in contact with the active portion may include an area below the guard ring that is disposed closest to the active portion.

[0040] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0041] [Figure 1] FIG. 1 is a top view illustrating an example of a semiconductor device 100 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of an area A in FIG. [Diagram 3] FIG. 3 is a diagram showing an example of a bb cross section in FIG. 2. [Figure 4] FIG. 2 is a diagram showing an example of a cc cross section in FIG. [Diagram 5] 5 shows an example of the carrier concentration distribution, the donor concentration distribution, and the defect density distribution in the dd line shown in FIG. [Figure 6] 1 is a diagram showing an example of an equipotential surface in an edge termination structure 90. FIG. [Figure 7] 5 shows other examples of the carrier concentration distribution, the donor concentration distribution, and the defect density distribution in the dd line shown in FIG. [Figure 8] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 9] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 10] FIG. 10 is a diagram showing an example of hydrogen concentration distribution along the ee line in FIG. [Figure 11] 10 is a diagram showing another example of the hydrogen concentration distribution on the ee line in FIG. [Figure 12] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 13] 2 is an enlarged cross-sectional view of the well region 11 and the guard ring 92 and their vicinity. [Figure 14] 13 is a diagram showing another example of the structure of the second high concentration region 202. FIG. [Figure 15] 13 is a diagram showing another example of the second high concentration region 202. FIG. [Figure 16A] 2A to 2C are diagrams illustrating a part of the manufacturing process of the semiconductor device 100. [Figure 16B] 2A to 2C are diagrams illustrating a part of the manufacturing process of the semiconductor device 100. [Figure 17A] 1 is a cross-sectional view of the vicinity of the emitter electrode 52 and the peripheral gate wiring 130. FIG. [Figure 17B] 1 is a cross-sectional view of the vicinity of the emitter electrode 52 and the peripheral gate wiring 130. FIG. [Figure 18] 13 is a diagram showing another example of a cross section in the vicinity of edge termination structure 90. FIG. [Figure 19] 13 is a diagram showing another example of a cross section in the vicinity of the emitter electrode 52 and the peripheral gate wiring 130. FIG. [Figure 20] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 21] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 22] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 23] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 24A] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 24B] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 25A] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 25B] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 26] 24B is a diagram showing an example of a method for forming the first high concentration region 304 described in FIG. 24A. FIG. [Figure 27] 25A and 25B. FIG. 25B shows an example of a method for forming the first high concentration region 304. [Figure 28] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Figure 29] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Diagram 30] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Diagram 31] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Diagram 32] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Diagram 33] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. [Diagram 34] 3 shows an example of a carrier concentration distribution in the dd line shown in FIG. 4 or FIG. [Diagram 35] 34 is a diagram showing the relationship between the dose ( / cm 2 ) of the N-type dopant in the second high concentration region 202 shown in FIG. 33 and the breakdown voltage (V) of the semiconductor device 100. FIG. [Diagram 36] 13 is a diagram showing another example of the relationship between the dose amount ( / cm 2 ) of the N-type dopant and the breakdown voltage (V) of the semiconductor device 100. FIG. [Figure 37] 3 is a flowchart showing an example of a manufacturing process of the semiconductor device 100. [Figure 38A] FIG. 13 shows an example of the first hydrogen injection step S508. [Figure 38B] 13 is a diagram showing an example of hydrogen ion implantation through a shielding member 351. FIG. [Figure 39] FIG. 13 is a diagram showing another example of the first hydrogen injection step S508. [Diagram 40] 10 is a flowchart showing another example of the manufacturing process of the semiconductor device 100. [Diagram 41] 1. FIG. 4 is a diagram showing another example of the cc cross section in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0043] In this specification, one side in a direction parallel to the depth direction of a semiconductor substrate is referred to as "upper" and the other side as "lower." Of the two main surfaces of a substrate, layer, or other member, one surface is referred to as the upper surface and the other surface is referred to as the lower surface. The directions of "upper" and "lower" are not limited to the direction of gravity or the directions when the semiconductor device is mounted.

[0044] In this specification, technical matters may be explained using orthogonal coordinate axes of X-axis, Y-axis, and Z-axis. The orthogonal coordinate axes merely identify the relative positions of components, and do not limit a specific direction. For example, the Z-axis does not limit the height direction relative to the ground. Note that the +Z-axis direction and the -Z-axis direction are opposite directions. When the Z-axis direction is described without indicating positive or negative, it means a direction parallel to the +Z-axis and -Z-axis.

[0045] In this specification, the orthogonal axes parallel to the upper and lower surfaces of the semiconductor substrate are the X-axis and the Y-axis. The axis perpendicular to the upper and lower surfaces of the semiconductor substrate is the Z-axis. In this specification, the direction of the Z-axis may be referred to as the depth direction. In this specification, the direction parallel to the upper and lower surfaces of the semiconductor substrate, including the X-axis and the Y-axis, may be referred to as the horizontal direction.

[0046] In this specification, when the term "same" or "equal" is used, it may include cases where there is an error due to manufacturing variations, etc. The error is, for example, within 10%.

[0047] In this specification, the conductivity type of a doped region doped with impurities is described as P type or N type. In this specification, the impurity may particularly mean either an N type donor or a P type acceptor, and may be described as a dopant. In this specification, doping means introducing a donor or an acceptor into a semiconductor substrate to make it a semiconductor exhibiting an N type conductivity type or a semiconductor exhibiting a P type conductivity type.

[0048] In this specification, the doping concentration means the concentration of donors or acceptors in a thermal equilibrium state. In this specification, the net doping concentration means the net concentration obtained by adding up the donor concentration as the concentration of positive ions and the acceptor concentration as the concentration of negative ions, including the polarity of the charge. As an example, the donor concentration is N D , acceptor concentration N A Then, the net doping concentration at any position is N D -N A It becomes.

[0049] A donor has the function of supplying electrons to a semiconductor. An acceptor has the function of receiving electrons from a semiconductor. Donors and acceptors are not limited to impurities themselves. For example, the VOH defect, which is a combination of vacancy (V), oxygen (O), and hydrogen (H) present in a semiconductor, functions as a donor that supplies electrons.

[0050] In this specification, when it is described as P+ type or N+ type, it means that the doping concentration is higher than that of P type or N type, and when it is described as P- type or N- type, it means that the doping concentration is lower than that of P type or N type. Also, when it is described as P++ type or N++ type, it means that the doping concentration is higher than that of P+ type or N+ type.

[0051] In this specification, the chemical concentration refers to the atomic density of an impurity measured regardless of the state of electrical activation. The chemical concentration can be measured, for example, by secondary ion mass spectrometry (SIMS). The above-mentioned net doping concentration can be measured by voltage-capacitance measurement (CV). The carrier concentration measured by spreading resistance measurement (SR) may be the net doping concentration. The carrier concentration measured by CV or SR may be a value in a thermal equilibrium state. In the N-type region, the donor concentration is sufficiently larger than the acceptor concentration, so the carrier concentration in the region may be the donor concentration. Similarly, in the P-type region, the carrier concentration in the region may be the acceptor concentration.

[0052] In addition, when the concentration distribution of the donor, acceptor or net doping has a peak, the peak value may be taken as the concentration of the donor, acceptor or net doping in the region. In cases where 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 may be taken as the concentration of the donor, acceptor or net doping.

[0053] The carrier concentration measured by the SR method may be lower than the concentration of the donor or acceptor. In the range where the current flows when measuring the spreading resistance, the carrier mobility of the semiconductor substrate may be lower than the value in the crystalline state. The reduction in carrier mobility occurs when the carriers are scattered due to a disorder in the crystal structure caused by lattice defects, etc.

[0054] The donor or acceptor concentration calculated from the carrier concentration measured by the CV method or the SR method may be lower than the chemical concentration of the element indicating the donor or acceptor. As an example, the donor concentration of phosphorus or arsenic, which acts as a donor in a silicon semiconductor, or the acceptor concentration of boron, which acts as an acceptor, is about 99% of the chemical concentration. On the other hand, the donor concentration of hydrogen, which acts as a donor in a silicon semiconductor, is about 0.1% to 10% of the chemical concentration of hydrogen.

[0055] Fig. 1 is a top view showing an example of a semiconductor device 100 according to an embodiment of the present invention. Fig. 1 shows the positions of each component projected onto the top surface of a semiconductor substrate 10. Fig. 1 shows only some of the components of the semiconductor device 100, and some components are omitted.

[0056] The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 has edges 102 in a top view. When simply referred to as a top view in this specification, it means that the semiconductor substrate 10 is viewed from the top surface side. The semiconductor substrate 10 of this example has two pairs of edges 102 that face each other in a top view. In FIG. 1, the X-axis and the Y-axis are parallel to either of the edges 102. The Z-axis is perpendicular to the top surface of the semiconductor substrate 10.

[0057] An active portion 160 is provided on the semiconductor substrate 10. The active portion 160 is a region through which a main current flows in the depth direction between the upper and lower surfaces of the semiconductor substrate 10 when the semiconductor device 100 is in operation. An emitter electrode is provided above the active portion 160, but is omitted in FIG.

[0058] The active section 160 is provided with at least one of a transistor section 70 including a transistor element such as an IGBT, and a diode section 80 including a diode element such as a free wheel diode (FWD). In the example of Fig. 1, the transistor section 70 and the diode section 80 are alternately arranged along a predetermined arrangement direction (the X-axis direction in this example) on the upper surface of the semiconductor substrate 10. In another example, the active section 160 may be provided with only one of the transistor section 70 and the diode section 80.

[0059] In FIG. 1, the region in which the transistor section 70 is arranged is marked with the symbol "I", and the region in which the diode section 80 is arranged is marked with the symbol "F". In this specification, the direction perpendicular to the arrangement direction in a top view may be referred to as the extension direction (Y-axis direction in FIG. 1). The transistor section 70 and the diode section 80 may each have a longitudinal direction in the extension direction. That is, the length of the transistor section 70 in the Y-axis direction is greater than its width in the X-axis direction. Similarly, the length of the diode section 80 in the Y-axis direction is greater than its width in the X-axis direction. The extension direction of the transistor section 70 and the diode section 80 may be the same as the longitudinal direction of each trench section described later.

[0060] The diode section 80 has an N+ type cathode region in a 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 section 80. In other words, the diode section 80 is a region that overlaps with the cathode region in a top view. A P+ type collector region may be provided in a region of the lower surface of the semiconductor substrate 10 other than the cathode region. In this specification, an extension region 81 in which the diode section 80 is extended in the Y-axis direction to a gate wiring to be described later may also be included in the diode section 80. A collector region is provided on the lower surface of the extension region 81.

[0061] 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 a gate structure, which has an N type emitter region, a P type base region, a gate conductive portion, and a gate insulating film, periodically arranged on the upper surface side of the semiconductor substrate 10.

[0062] 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 112. The semiconductor device 100 may also have pads such as an anode pad, a cathode pad, and a current detection pad. Each pad is disposed near an end edge 102. The vicinity of the end edge 102 refers to the region between the end edge 102 and the emitter electrode in a top view. When the semiconductor device 100 is mounted, each pad may be connected to an external circuit via wiring such as a wire.

[0063] A gate potential is applied to the gate pad 112. The gate pad 112 is electrically connected to a 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 112 and the gate trench portion. In FIG. 1, the gate wiring is hatched with oblique lines.

[0064] The gate wiring in this example has a peripheral gate wiring 130 and an active side gate wiring 131. The peripheral gate wiring 130 is disposed between the active portion 160 and the edge 102 of the semiconductor substrate 10 in a top view. The peripheral gate wiring 130 in this example surrounds the active portion 160 in a top view. The area surrounded by the peripheral gate wiring 130 in a top view may be the active portion 160. The peripheral gate wiring 130 is connected to the gate pad 112. The peripheral gate wiring 130 is disposed above the semiconductor substrate 10. The peripheral gate wiring 130 may be a metal wiring containing aluminum or the like.

[0065] The active side gate wiring 131 is provided in the active section 160. By providing the active side gate wiring 131 in the active section 160, the variation in wiring length from the gate pad 112 for each region of the semiconductor substrate 10 can be reduced.

[0066] The active side gate wiring 131 is connected to a gate trench portion of the active section 160. The active side gate wiring 131 is disposed above the semiconductor substrate 10. The active side gate wiring 131 may be a 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. In this example, the active side gate wiring 131 is provided extending in the X axis direction from one peripheral gate wiring 130 to the other peripheral gate wiring 130 at approximately the center in the Y axis direction so as to cross the active section 160. When the active section 160 is divided by the active side gate wiring 131, the transistor section 70 and the diode section 80 may be arranged alternately in the X axis direction in each divided region.

[0068] Furthermore, the semiconductor device 100 may include a temperature sensor (not shown) that is a PN junction diode formed of polysilicon or the like, and a current detector (not shown) that simulates the operation of a transistor section provided in the active section 160.

[0069] The semiconductor device 100 of this example includes an edge termination structure 90 between the active section 160 and the edge 102. The edge termination structure 90 of this example is disposed between the peripheral gate wiring 130 and the edge 102. The edge termination structure 90 relieves electric field concentration on the upper surface side of the semiconductor substrate 10. The edge termination structure 90 has a plurality of guard rings 92. The guard rings 92 are P-type regions in contact with the upper surface of the semiconductor substrate 10. The guard rings 92 may surround the active section 160 in a top view. The multiple guard rings 92 are disposed at predetermined intervals between the peripheral gate wiring 130 and the edge 102. The guard ring 92 disposed on the outer side may surround the guard ring 92 disposed one step inward. The outer side refers to the side closer to the edge 102, and the inner side refers to the side closer to the peripheral gate wiring 130. By providing multiple guard rings 92, the depletion layer on the upper surface side of active portion 160 can be extended outward, improving the breakdown voltage of semiconductor device 100. Edge termination structure 90 may further include at least one of a field plate and a resurf provided in an annular shape surrounding active portion 160.

[0070] 2 is an enlarged view of region A in FIG. 1. Region A is a region including a transistor section 70, a diode section 80, and an active side gate wiring 131. The semiconductor device 100 of this example includes a gate trench section 40, a dummy trench section 30, a well region 11, an emitter region 12, a base region 14, and a contact region 15 provided inside the upper surface side of a semiconductor substrate 10. The gate trench section 40 and the dummy trench section 30 are each an example of a trench section. The semiconductor device 100 of this example also 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 active side gate wiring 131 and the upper surface of the semiconductor substrate 10, but is omitted in Fig. 1. In the interlayer insulating film of this example, contact holes 54 are provided so as to penetrate the interlayer insulating film. In Fig. 2, each contact hole 54 is hatched with oblique lines.

[0072] The emitter electrode 52 is provided above the gate trench portion 40, the dummy trench 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 a contact hole 54. The emitter electrode 52 is also connected to a dummy conductive portion in the dummy trench portion 30 through a contact hole provided in the interlayer insulating film. The emitter electrode 52 may be connected to the dummy conductive portion of the dummy trench portion 30 at the tip of the dummy trench portion 30 in the Y-axis direction.

[0073] The active side gate wiring 131 is connected to the gate trench portion 40 through a contact hole provided in the interlayer insulating film. The active side gate wiring 131 may be connected to the gate conductive portion of the gate trench portion 40 at the tip portion 41 of the gate trench portion 40 in the Y-axis direction. The active side gate wiring 131 is not connected to the dummy conductive portion in the dummy trench portion 30.

[0074] The emitter electrode 52 is made of a material containing metal. FIG. 2 shows the range in which the emitter electrode 52 is provided. For example, at least a portion of the emitter electrode 52 is made 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 made of titanium, a titanium compound, or the like, below the region made of aluminum or the like. Furthermore, the emitter electrode 52 may have a plug formed by embedding tungsten or the like in the contact hole so as to contact the barrier metal and aluminum or the like.

[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 so as to extend by a predetermined width to an area where it does not overlap with the active side gate wiring 131. The well region 11 in this example is provided away from the end of the contact hole 54 in the Y-axis direction toward the active side gate wiring 131. The well region 11 is a region of a second conductivity type having a higher doping concentration than the base region 14. In this example, the base region 14 is P- type, and the well region 11 is P+ type.

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

[0077] The gate trench portion 40 in this example may have two straight line portions 39 (portions of the trench that are straight along the extension direction) extending along an extension direction perpendicular to the arrangement direction, and a tip portion 41 connecting the two straight line portions 39. The extension direction in FIG. 2 is the Y-axis direction.

[0078] At least a part of the tip portion 41 is preferably curved in a top view. By connecting the ends of the two straight portions 39 in the Y-axis direction with each other by the tip portion 41, electric field concentration at the ends of the straight portions 39 can be alleviated.

[0079] In the transistor section 70, the dummy trench section 30 is provided between the respective straight line portions 39 of the gate trench section 40. One dummy trench section 30 may be provided between the respective straight line portions 39, or a plurality of dummy trench sections 30 may be provided. The dummy trench section 30 may have a straight line shape extending in the extension direction, and may have a straight line portion 29 and a tip section 31, similar to the gate trench section 40. The semiconductor device 100 shown in FIG. 2 includes both a straight line dummy trench section 30 without a tip section 31 and a dummy trench section 30 with a tip section 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 in the Y-axis direction of the gate trench portion 40 and the dummy trench portion 30 are provided in the well region 11 when viewed from above. That is, at the ends in the Y-axis direction of each trench portion, the bottoms in the depth direction of each trench portion are covered by the well region 11. This makes it possible to alleviate electric field concentration at the bottoms of each trench portion.

[0081] A mesa portion is provided between each trench portion in the arrangement direction. The mesa portion refers to a region sandwiched between the trench portions 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 trench portion. The mesa portion in this example is provided on the upper surface of the semiconductor substrate 10, extending in the extension direction (Y-axis direction) along the trench. In this example, the transistor portion 70 is provided with a mesa portion 60, and the diode portion 80 is provided with a mesa portion 61. In this specification, when the term "mesa portion" is simply used, it refers to each of the mesa portion 60 and the mesa portion 61.

[0082] A base region 14 is provided in each mesa portion. Of the base regions 14 exposed on the upper surface of the semiconductor substrate 10 in the mesa portion, the region closest to the active side gate wiring 131 is defined as the base region 14-e. In FIG. 2, the base region 14-e is shown at one end in the extension direction of each mesa portion, but the base region 14-e is also provided at the other end of each mesa portion. In each mesa portion, at least one of the emitter region 12 of the first conductivity type and the contact region 15 of the second conductivity type may be provided in a region sandwiched between the base regions 14-e in a top view. In this example, the emitter region 12 is N+ type, and the contact region 15 is P+ type. The emitter region 12 and the contact region 15 may be provided 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] Each of the contact region 15 and the emitter region 12 in the mesa portion 60 is provided from one trench portion to the other trench portion in the X-axis direction. As an example, the contact region 15 and the emitter region 12 in the mesa portion 60 are alternately arranged along the extension direction of the trench portion (the Y-axis direction).

[0085] In another example, the contact region 15 and the emitter region 12 of the mesa portion 60 may be provided in a stripe shape along the extension direction (Y-axis direction) of the trench portion. For example, the emitter region 12 is provided in a region in contact with the trench portion, and the contact region 15 is provided in a region sandwiched between the emitter regions 12.

[0086] No emitter region 12 is provided in the mesa portion 61 of the diode portion 80. A base region 14 and a contact region 15 may be provided on the upper surface of the mesa portion 61. In a region sandwiched between the base regions 14-e on the upper surface of the mesa portion 61, a contact region 15 may be provided in contact with each of the base regions 14-e. In a region sandwiched between the contact regions 15 on the upper surface of the mesa portion 61, a base region 14 may be provided. The base region 14 may be disposed in the entire region sandwiched between the contact regions 15.

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

[0088] In the diode section 80, an N+ type cathode region 82 is provided in a region adjacent to the lower surface of the semiconductor substrate 10. 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. In FIG. 2, the boundary between the cathode region 82 and the collector region 22 is indicated by a dotted line.

[0089] The cathode region 82 is disposed away from the well region 11 in the Y-axis direction. This ensures a distance between the cathode region 82 and a P-type region (well region 11) that has a relatively high doping concentration and is formed to a deep position, thereby improving the breakdown voltage. In this example, the end of the cathode region 82 in the Y-axis direction is disposed farther from the well region 11 than the end of the contact hole 54 in the Y-axis direction. In another example, the end of the cathode region 82 in the Y-axis direction may be disposed between the well region 11 and the contact hole 54.

[0090] 3 is a diagram showing an example of the bb cross section in FIG. 2. The bb cross section is an XZ plane passing through the emitter region 12 and the cathode region 82. In this cross section, the semiconductor device 100 of this example has a semiconductor substrate 10, an interlayer insulating film 38, an emitter electrode 52, and a collector electrode 24. 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 layer of an insulating film such as silicate glass doped with impurities such as boron or phosphorus, a thermal oxide film, and other insulating films. The interlayer insulating film 38 is provided with the contact hole 54 described in FIG. 2.

[0091] The emitter electrode 52 is provided above the interlayer insulating film 38. The emitter electrode 52 passes through a contact hole 54 in the interlayer insulating film 38 and is in contact with the upper surface 21 of the semiconductor substrate 10. 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 made of a metal material such as aluminum. In this specification, the direction connecting the emitter electrode 52 and the collector electrode 24 (the Z-axis direction) is referred to as the depth direction.

[0092] The semiconductor substrate 10 has an N-type bulk doped region 18. The bulk doped region 18 is a region in which the doping concentration of the bulk doped region 18 matches the donor concentration of a bulk donor. The bulk donor will be described later. The bulk doped region 18 is provided in each of the transistor section 70 and the diode section 80.

[0093] In the mesa portion 60 of the transistor section 70, an N+ type emitter region 12 and a P- type base region 14 are provided in this order from the upper surface 21 side of the semiconductor substrate 10. A bulk doping 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 disposed between the base region 14 and the bulk doping region 18.

[0094] The emitter region 12 is exposed on the upper surface 21 of the semiconductor substrate 10 and is 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 emitter region 12 has a higher doping concentration than the bulk doping region 18.

[0095] 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 trench portions on both sides of the mesa portion 60.

[0096] 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 bulk doping region 18. By providing the high-concentration accumulation region 16 between the bulk doping region 18 and the base region 14, the carrier injection enhancement effect (IE effect) can be enhanced and the on-voltage can be reduced. The accumulation region 16 may be provided so as to cover the entire lower surface of the base region 14 in each mesa portion 60.

[0097] A P-type base region 14 is provided in the mesa portion 61 of the diode portion 80 in contact with the upper surface 21 of the semiconductor substrate 10. A bulk doping region 18 is provided below the base region 14. An accumulation region 16 may be provided below the base region 14 in the mesa portion 61.

[0098] In each of the transistor section 70 and the diode section 80, an N+ type buffer region 20 may be provided under the bulk doping region 18. The doping concentration of the buffer region 20 is higher than that of the bulk doping region 18. The buffer region 20 has one or more donor concentration peaks having a higher donor concentration than the bulk doping region 18. The multiple donor concentration peaks are disposed at different positions in the depth direction of the semiconductor substrate 10. The donor concentration peaks of the buffer region 20 may be, for example, concentration peaks of hydrogen (protons) or phosphorus. The buffer region 20 may function as a field stop layer that prevents a 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.

[0099] 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 a different acceptor. The acceptor of the collector region 22 is, for example, boron.

[0100] In the diode section 80, an N+ type cathode region 82 is provided under the buffer region 20. The donor concentration of the cathode region 82 is higher than the donor concentration of the bulk doping region 18. The donor of the cathode region 82 is, for example, hydrogen or phosphorus. The elements serving as the donor and acceptor of each region are not limited to the above-mentioned examples. The collector region 22 and the cathode region 82 are exposed to 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.

[0101] At least one gate trench portion 40 and at least one dummy trench portion 30 are provided on the upper surface 21 side of the semiconductor substrate 10. Each trench portion passes through the base region 14 from the upper surface 21 of the semiconductor substrate 10 to reach the bulk doping region 18. In a region where at least one of the emitter region 12, the contact region 15, and the accumulation region 16 is provided, each trench portion passes through these doping regions to reach the bulk doping region 18. The trench portion passing through the doping region is not limited to a case where the trench portion is formed in the order of forming the doping region and then the trench portion. A case where the trench portion is formed and then the doping region is formed between the trench portions is also included in the case where the trench portion passes through the doping region.

[0102] 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 is not provided with the gate trench portion 40. 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.

[0103] The gate trench portion 40 has 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 on the inner wall of the gate trench. The gate conductive portion 44 is provided inside the gate insulating film 42 within the gate trench. In other words, 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.

[0104] The gate conductive portion 44 may be provided longer in the depth direction than the base region 14. The gate trench portion 40 in this cross section is covered with an interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10. The gate conductive portion 44 is electrically connected to the gate wiring. When a predetermined gate voltage is applied to the gate conductive portion 44, a channel is formed by an electron inversion layer in the surface layer of the interface of the base region 14 that contacts the gate trench portion 40.

[0105] The dummy trench portion 30 may have the same structure as the gate trench portion 40 in the cross section. The dummy trench portion 30 has a dummy trench, a dummy insulating film 32, and a dummy conductive portion 34 provided on the upper surface 21 of the semiconductor substrate 10. The dummy conductive portion 34 may be connected to an electrode different from the gate pad. For example, the dummy conductive portion 34 may be connected to a dummy pad (not shown) that is connected to an external circuit different from the gate pad, and may be controlled differently from the gate conductive portion 44. The dummy conductive portion 34 may also be electrically connected to the emitter electrode 52. The dummy insulating film 32 is provided to cover the inner wall of the dummy trench. The dummy conductive portion 34 is provided inside the dummy trench and is provided on the inner side of 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.

[0106] The gate trench portion 40 and the dummy trench portion 30 in this example are covered with an interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10. The bottoms of the dummy trench portion 30 and the gate trench portion 40 may be curved and convex downward (curved in cross section).

[0107] The semiconductor substrate 10 has a first conductivity type (N type) bulk donor distributed throughout. The bulk donor is a donor due to a dopant that is contained substantially uniformly in the ingot when the ingot that is the base of the semiconductor substrate 10 is manufactured. The bulk donor in this example is an element other than hydrogen. The dopant of the bulk donor is, for example, phosphorus or antimony, but is not limited thereto. The bulk donor in this example is phosphorus. The bulk donor is also contained in the P type region. The semiconductor substrate 10 may be a wafer cut from a semiconductor ingot, or may be a chip obtained by dividing the wafer. The semiconductor ingot may be manufactured by any of the Czochralski method (CZ method), the magnetic field application type Czochralski method (MCZ method), and the float zone method (FZ method). The ingot in this example is manufactured by the MCZ method. The bulk doped region 18 is a region in which the doping concentration of the bulk doped region 18 matches the donor concentration of the bulk donor. For example, the donor concentration of the bulk donor may be between 90% and 100% of the chemical concentration of the dopant of the bulk donor.

[0108] The semiconductor substrate 10 is disposed on the upper surface 21 side of the semiconductor substrate 10, and has a hydrogen peak portion 302 where the hydrogen concentration shows a peak in the hydrogen concentration distribution in the depth direction of the semiconductor substrate 10. The upper surface 21 side of the semiconductor substrate 10 is a region between the center position in the depth direction of the semiconductor substrate 10 and the upper surface 21. The lower surface 23 side is a region between the center position in the depth direction of the semiconductor substrate 10 and the lower surface 23. The hydrogen peak portion 302 may have a donor concentration distribution that reflects the peak shape of the hydrogen concentration distribution. The donor concentration at the peak portion of the hydrogen peak portion 302 is higher than the donor concentration of a bulk donor.

[0109] Hydrogen ions such as protons are implanted into the hydrogen peak portion 302 from the lower surface 23 of the semiconductor substrate 10. In the passing region through which the hydrogen ions have passed, vacancy-based lattice defects such as monovacancies (V) and polyvacancies (VV) are formed. Atoms adjacent to the vacancies have dangling bonds. Lattice defects include interstitial atoms and dislocations, and may also include donors and acceptors in a broad sense. In this specification, vacancy-based lattice defects may be referred to as vacancy-type lattice defects, vacancy-type defects, or simply lattice defects. In addition, the implantation of hydrogen ions into the semiconductor substrate 10 may cause a large number of lattice defects to be formed, which may strongly disturb the crystallinity of the semiconductor substrate 10. In this specification, this disturbance in crystallinity may be referred to as disorder. In addition, as the hydrogen injected into the hydrogen peak portion 302 diffuses, the vacancies (V) and oxygen (O) present in the passing region are bonded to hydrogen (H), forming VOH defects. The VOH defects function as donors that supply electrons. As a result, an N-type first high concentration region 304, in which the donor concentration is higher than the doping concentration of the bulk donor, is formed in the region between the hydrogen peak portion 302 and the lower surface 23 of the semiconductor substrate 10. In this specification, the VOH defect may be simply referred to as a hydrogen donor. The first high concentration region 304 in this example contains a hydrogen donor. The bulk doping region 18 and the first high concentration region 304 may be collectively referred to as a drift region 19. The drift region 19 may be a region in which a depletion layer spreads when a voltage is applied to the semiconductor device 100, supporting more than half of the applied voltage.

[0110] The first high concentration region 304 has an upper surface or an upper end disposed on the upper surface 21 side of the semiconductor substrate 10, and a lower surface or a lower end disposed on the lower surface 23 side of the semiconductor substrate 10. The first high concentration region 304 includes a hydrogen peak portion 302. The first high concentration region 304 may be provided continuously from the hydrogen peak portion 302 to the lower surface 23. However, the first high concentration region 304 does not have to be provided in a region from the hydrogen peak portion 302 to the lower surface 23 where the buffer region 20, the collector region 22, or the cathode region 82 are provided. The first high concentration region 304 in this example is provided in the region from the hydrogen peak portion 302 to the buffer region 20.

[0111] A first high concentration region 304 may also be provided above the hydrogen peak portion 302. The hydrogen concentration peak has a predetermined half-width in the depth direction. Therefore, hydrogen is also injected above the hydrogen peak portion 302 where the hydrogen concentration is maximum, and vacancy-type defects are formed. Therefore, a first high concentration region 304 is also formed above the hydrogen peak portion 302. However, the first high concentration region 304 above the hydrogen peak portion 302 has a smaller width in the Z-axis direction than the first high concentration region 304 below the hydrogen peak portion 302.

[0112] The hydrogen peak portion 302 may have a lifetime adjustment function. That is, the carrier lifetime may show a minimum value in the vicinity of the hydrogen peak portion 302. When the density of vacancy-type defects formed in the vicinity of the hydrogen peak portion 302 is sufficiently higher than the oxygen concentration present in the vicinity of the hydrogen peak portion 302, the density of vacancy-type defects remaining without becoming hydrogen donors becomes high. The remaining vacancy-type defects and carriers recombine with each other, shortening the carrier lifetime. The hydrogen peak portion 302 may have a lifetime adjustment function. Also, when the density of vacancy-type defects formed in the hydrogen peak portion 302 is not sufficiently higher than the oxygen concentration present in the hydrogen peak portion 302, most of the vacancy-type defects become hydrogen donors. The hydrogen peak portion 302 may not have a lifetime adjustment function and may function as a donor region with a high donor concentration.

[0113] Figure 4 is a diagram showing an example of a cc cross section in Figure 1. The cc cross section is an XZ plane passing through the edge termination structure portion 90, the transistor portion 70, and the diode portion 80. The structures of the transistor portion 70 and the diode portion 80 are the same as those of the transistor portion 70 and the diode portion 80 described in Figures 2 and 3. In Figure 4, the structures of the gate trench portion 40 and the dummy trench portion 30 are shown in a simplified manner.

[0114] In the semiconductor substrate 10, a well region 11 is provided between the edge termination structure portion 90 and the transistor portion 70. The well region 11 is a P+ type region in contact with the upper surface 21 of the semiconductor substrate 10. The well region 11 may be provided to a position deeper than the lower ends of the gate trench portion 40 and the dummy trench portion 30. A portion of the gate trench portion 40 and the dummy trench portion 30 may be disposed inside the well region 11.

[0115] An interlayer insulating film 38 covering the well region 11 may be provided on the upper surface 21 of the semiconductor substrate 10. Electrodes and wiring such as an emitter electrode 52 and a peripheral gate wiring 130 are provided above the interlayer insulating film 38. The emitter electrode 52 is provided extending from above the active portion 160 to above the well region 11. The emitter electrode 52 may be connected to the well region 11 via a contact hole provided in the interlayer insulating film 38.

[0116] The peripheral gate wiring 130 is disposed between the emitter electrode 52 and the edge termination structure 90. The emitter electrode 52 and the peripheral gate wiring 130 are disposed separately from each other, but the gap between the emitter electrode 52 and the peripheral gate wiring 130 is omitted in Figure 4. The peripheral gate wiring 130 is electrically insulated from the well region 11 by the interlayer insulating film 38.

[0117] The edge termination structure 90 includes a plurality of guard rings 92, a plurality of second high concentration regions 202, a plurality of field plates 94, and a channel stopper 174. The hydrogen peak portion 302 and the first high concentration region 304 described in FIG. 3 are also provided in at least a portion of the edge termination structure 90. The first high concentration region 304 may be provided below the guard ring 92. The hydrogen peak portion 302 and the first high concentration region 304 of the edge termination structure 90 may be provided contiguous with the hydrogen peak portion 302 and the first high concentration region 304 of the transistor portion 70 and the diode portion 80. The hydrogen peak portion 302 and the first high concentration region 304 may be provided across the entire edge termination structure 90 in the X-axis direction.

[0118] The hydrogen peak portion 302 in this example is provided below the second high concentration region 202 (i.e., at a position deeper than the second high concentration region 202 when viewed from the upper surface 21). The hydrogen peak portion 302 may be located at a position deeper than the lower end of the guard ring 92. In other words, the hydrogen peak portion 302 may be located between the lower end of the guard ring 92 and the lower surface 23 of the semiconductor substrate 10. The hydrogen peak portion 302 may be located at a position deeper than the lower end of the well region 11. The hydrogen peak portion 302 may be located at a position deeper than the lower end of the trench portion.

[0119] Although the first high concentration region 304 shown in FIG. 4 is not in contact with the guard ring 92, the first high concentration region 304 may be in contact with the lower end of the guard ring 92. The first high concentration region 304 may be provided up to between two guard rings 92. The first high concentration region 304 may or may not be in contact with the well region 11. The first high concentration region 304 may or may not be in contact with the trench portion. The first high concentration region 304 may be provided below the second high concentration region 202.

[0120] The first high concentration region 304 may be in contact with the well region 11. The first high concentration region 304 may be in contact with the trench portion. The first high concentration region 304 may not be in contact with any of the emitter region 12, the base region 14, and the accumulation region 16. In another example, the first high concentration region 304 may be in contact with the accumulation region 16. The first high concentration region 304 may be in contact with the base region 14. The first high concentration region 304 may or may not be in contact with the channel stopper 174.

[0121] The first highly concentrated region 304 may have the same or different depth lengths throughout the entire edge termination structure 90. The first highly concentrated region 304 may have the same or different depth lengths in the edge termination structure 90 and the active section 160.

[0122] In edge termination structure 90, collector region 22 may be provided in a region in contact with lower surface 23. Each guard ring 92 may be provided to surround active portion 160 on upper surface 21. The multiple guard rings 92 may have the function of spreading a depletion layer generated in active portion 160 to the outside of semiconductor substrate 10. This makes it possible to prevent electric field concentration inside semiconductor substrate 10, and improve the breakdown voltage of semiconductor device 100.

[0123] The guard ring 92 in this example is a P+ type semiconductor region formed by ion implantation near the top surface 21. The guard ring 92 can be formed by selectively implanting a P type dopant such as boron from the top surface 21 of the semiconductor substrate 10, followed by heat treatment. The depth of the bottom of the guard ring 92 may be deeper than the depth of the bottom of the gate trench portion 40 and the dummy trench portion 30. The depth of the bottom of the guard ring 92 may be the same as or different from the depth of the bottom of the well region 11.

[0124] The upper surface of the guard ring 92 is covered with the interlayer insulating film 38. The field plate 94 is made of a metal such as aluminum or a conductive material such as polysilicon. The field plate 94 may be made of a metal alloy such as an aluminum-silicon alloy, for example, AlSi or AlSiCu. The field plate 94 may be made of the same material as the peripheral gate wiring 130 or the emitter electrode 52. The field plate 94 is provided on the interlayer insulating film 38. The field plate 94 in this example is connected to the guard ring 92 through a through hole provided in the interlayer insulating film 38.

[0125] The channel stopper 174 is provided so as to be exposed on the top surface 21 and the sidewalls in the vicinity of the edge 102 of the semiconductor substrate 10. The channel stopper 174 is an N-type region having a higher doping concentration than the bulk doping region 18. The channel stopper 174 has a function of terminating a depletion layer generated in the active portion 160 in the vicinity of the edge 102 of the semiconductor substrate 10. Note that at least a portion of the field plate 94, the peripheral gate wiring 130, and the emitter electrode 52 are covered with a protective film such as a polyimide or nitride film, but the protective film may be omitted in the drawings in this specification.

[0126] The second high concentration region 202 is an N-type region having a donor concentration higher than the doping concentration of the bulk donor. The second high concentration region 202 is provided between two adjacent guard rings 92. The second high concentration region 202 may be in contact with the upper surface 21 of the semiconductor substrate 10. In this example, the second high concentration region 202 is provided in a range from the upper surface 21 to a position shallower than the lower end of the guard ring 92. In another example, the second high concentration region 202 may be provided to a position deeper than the lower end of the guard ring 92. The second high concentration region 202 may also be provided between the well region 11 and the guard ring 92.

[0127] The second high concentration region 202 may be formed by injecting a donor from the upper surface 21 of the semiconductor substrate 10 using the field plate 94 as a mask, and performing a heat treatment. In this case, at least a part of the second high concentration region 202 is formed in a region not covered by the field plate 94. At least a part of the second high concentration region 202 in this example does not overlap with the field plate 94 in the Z-axis direction. The donor implanted into the second high concentration region 202 may be phosphorus, hydrogen, or another donor. When the second high concentration region 202 is formed deep, the acceleration energy of the donor may be changed and the donor may be implanted at a plurality of depth positions.

[0128] In another example, the second high concentration region 202 may be formed by implanting a donor from the upper surface 21 of the semiconductor substrate 10 without using the field plate 94 as a mask, and performing a heat treatment. In this case, boron is selectively ion-implanted as a P-type dopant, and a guard ring is formed by a heat treatment. Thereafter, phosphorus is ion-implanted as an N-type dopant, and the second high concentration region 202 is formed by a heat treatment. The temperature of the heat treatment after the P-type dopant is implanted is higher than the temperature of the heat treatment after the N-type dopant is implanted. The dose of the N-type dopant in the ion implantation may be lower than the dose of the P-type dopant. In this case, the N-type dopant may be ion-implanted into the region where the guard ring is to be formed, or may be selectively implanted to avoid the region where the guard ring is to be formed.

[0129] 4, the second high concentration region 202 and the first high concentration region 304 are disposed apart from each other in the Z-axis direction. A region having the same donor concentration as the bulk donor concentration may be provided between the second high concentration region 202 and the first high concentration region 304. The first high concentration region 304 may reach the upper surface 21.

[0130] Note that if a long-term heat treatment is performed at high temperature after hydrogen injection, the hydrogen donors will disappear, or the lifetime adjustment function of the hydrogen peak portion 302 will disappear. For this reason, it is preferable to perform the hydrogen injection and heat treatment steps at the end of the manufacturing process of the semiconductor device 100. For example, the disappearance of the hydrogen donors can be suppressed by injecting hydrogen after forming a protective film above the field plate 94, etc.

[0131] Variations in the doping concentration on the top surface 21 side of the edge termination structure 90 will also result in variations in the extent of the depletion layer in the edge termination structure 90. If second high concentration region 202 and first high concentration region 304 are not provided, bulk doping region 18 with a bulk donor concentration will occupy a large area on the top surface 21 side of the edge termination structure 90. The bulk donor concentration is the concentration of donors that is contained in the semiconductor substrate 10 from the time of manufacture, and is therefore relatively prone to variation.

[0132] In contrast, the second high concentration region 202 and the first high concentration region 304 are formed by ion implantation or the like. Since the concentration of ion implantation is relatively easy to control, the variation in donor concentration of the second high concentration region 202 and the first high concentration region 304 is relatively small. Therefore, by providing the second high concentration region 202 and the first high concentration region 304, the variation in the extent to which the depletion layer extending from below the well region 11 to the edge termination structure 90 spreads in the X-axis direction can be reduced, and the variation in the breakdown voltage of the semiconductor device 100 can also be reduced. Furthermore, by providing the second high concentration region 202 and the first high concentration region 304, the depletion layer can be prevented from spreading too far in the X-axis direction in the edge termination structure 90.

[0133] Figure 5 shows an example of the carrier concentration distribution, donor concentration distribution, and defect density distribution for the dd line shown in Figure 4. The dd line passes through second highly doped region 202, bulk doping region 18, first highly doped region 304, buffer region 20, and collector region 22 in edge termination structure 90. The carrier concentration distribution may be the same as the net doping concentration distribution as described above.

[0134] In this example, the bulk donor is phosphorus. The second high concentration region 202 is formed by implanting phosphorus from the upper surface 21 of the semiconductor substrate 10. The upper part of FIG. 5 shows the carrier concentration distribution, and the lower part of FIG. 5 shows the phosphorus concentration distribution in the second high concentration region 202, the hydrogen concentration distribution in the first high concentration region 304, and the VOH defect density distribution. In this example, the bulk donor concentration is N B The bulk donor concentration is approximately uniform throughout the depth direction. The bulk donor concentration may be the minimum value of the concentration of donors distributed throughout the semiconductor substrate 10. For example, when phosphorus is distributed throughout the semiconductor substrate 10, the bulk donor concentration may be the minimum value of the concentration of phosphorus in the semiconductor substrate 10.

[0135] The phosphorus concentration distribution in the second high concentration region 202 has a first peak 318 where the phosphorus concentration reaches a maximum value. The depth position of the first peak 318 corresponds to the phosphorus implantation position. The hydrogen concentration distribution in the first high concentration region 304 reaches a maximum value at the hydrogen peak portion 302. Since hydrogen is implanted from the lower surface 23 of the semiconductor substrate 10, the slope 322 of the hydrogen concentration distribution on the upper surface 21 side of the hydrogen peak portion 302 is steeper than the slope 320 of the hydrogen concentration distribution on the lower surface 23 side of the hydrogen peak portion 302. In this example, the phosphorus concentration and the hydrogen concentration are the chemical concentrations of phosphorus and hydrogen.

[0136] The VOH defect density distribution may be a distribution that reflects the hydrogen concentration distribution or a distribution similar to the hydrogen concentration distribution. For example, the positions of inflection points such as maximum, minimum, and kink of each distribution may be located at approximately the same depth position. The approximately same depth position may have an error smaller than the full width at half maximum of the peak of the hydrogen concentration distribution, for example. The VOH defect density distribution may have a flat portion 323 with approximately uniform density on the lower surface 23 side than the hydrogen peak portion 302. The VOH defect density distribution may be the same as the distribution of the first high concentration region 304. For example, the concentration of the VOH defect density distribution may be the first high concentration region 304.

[0137] A VOH defect is a defect in which hydrogen, oxygen, and vacancy type defects are combined. For this reason, the VOH defect density distribution may be limited by the distribution of an element with a low concentration or density among hydrogen, oxygen, and vacancy type defects. When oxygen is distributed almost uniformly in the semiconductor substrate 10, if the vacancy concentration is relatively small, the VOH defect density distribution has a flat portion 323. In another example, the VOH defect density may gradually decrease toward the lower surface 23 side, similar to the slope 320 of the hydrogen concentration distribution. For example, if the hydrogen concentration is relatively small in a portion other than the hydrogen peak portion 302, the VOH defect density distribution reflects the hydrogen concentration distribution.

[0138] The carrier concentration distribution in this example has a peak 312 at the same depth as the hydrogen peak portion 302. Also, in the second high concentration region 202, a peak 314 is at the same depth as the first peak 318 of the phosphorus concentration distribution. When the distance D1 between the peaks 312 and 314 is sufficiently large, the bulk donor concentration N B The base carrier concentration N 00 A bulk doping region 18 having a distance D1 is provided. The distance D1 is the distance between the apex of the peak 312 and the apex of the peak 314. The distance D1 may be the distance between the apex of the first peak 318 and the apex of the hydrogen peak portion 302. In this specification, the distance D1 may be used as the distance in the Z-axis direction between the hydrogen peak portion 302 and the second high concentration region 202.

[0139] The first high concentration region 304 may have a flat portion 313 between the peak 312 and the buffer region 20, in which the carrier concentration is substantially uniform. The flat portion 313 may have a carrier concentration varying in a range of not less than the minimum value N0 and not more than twice the minimum value N0 of the carrier concentration between the peak 312 and the buffer region 20. The flat portion 313 may have a carrier concentration varying in a range of not less than the minimum value N0 and not more than 1.5 times the minimum value N0, or may have a carrier concentration varying in a range of not less than the minimum value N0 and not more than 1.2 times the minimum value N0. The length of the flat portion 313 in the Z-axis direction may be not less than half the length of the first high concentration region 304 in the Z-axis direction. The first high concentration region 304 may have a carrier concentration gradually decreasing from the peak 312 toward the buffer region 20.

[0140] Similarly, the VOH defect density of the flat portion 323 may vary in a range from the minimum value of the VOH defect density between the hydrogen peak portion 302 and the buffer region 20 to twice the minimum value. The VOH defect density of the flat portion 313 may vary in a range from the minimum value to 1.5 times the minimum value, or may vary in a range from the minimum value to 1.2 times the minimum value. The length of the flat portion 323 in the Z-axis direction may be half or more of the length of the first high concentration region 304 in the Z-axis direction.

[0141] The peak value N1 of the carrier concentration in the second high concentration region 202 is greater than the minimum value N0 of the carrier concentration in the first high concentration region 304. The peak value N1 may be two or more times, five or more times, ten or more times, or even twenty or more times the minimum value N0. The peak value N1 is a value obtained by multiplying the base carrier concentration N 00 The base carrier concentration N in this example may be 10 times or more, or may be 100 times or more. 00 is the doping concentration of bulk donors.

[0142] Figure 6 is a diagram showing an example of equipotential surfaces in the edge termination structure 90. The hydrogen peak portion 302 is omitted in Figure 6. Also, the hatching in the first high concentration region 304 is omitted.

[0143] 6 shows an equipotential surface 306 when the second high concentration region 202 and the first high concentration region 304 are provided, an equipotential surface 308 when the first high concentration region 304 is provided without providing the second high concentration region 202, and an equipotential surface 310 when the second high concentration region 202 and the first high concentration region 304 are not provided. The equipotential surfaces 306, 308, and 310 are all equipotential surfaces at a predetermined potential Vo.

[0144] If the second high concentration region 202 and the first high concentration region 304 are not provided, the equipotential surface 310 spreads in the depth direction and the circumferential direction of the semiconductor substrate 10. The spread of the equipotential surface 310 is determined by the donor concentration of the bulk donor. Since the donor concentration of the bulk donor is set to a low value, the spread of the equipotential surface 310 is larger in both the depth direction and the circumferential direction of the semiconductor substrate than the equipotential surfaces 306 and 308.

[0145] In the case where the first high concentration region 304 is provided without providing the second high concentration region 202, the donor concentration of the bulk donor is lower than the donor concentration of the first high concentration region 304. Therefore, the curvature of the equipotential surface 308 changes at the boundary surface between the bulk doping region 18 and the first high concentration region 304. As a result, the equipotential surface 308 spreads toward the outer periphery of the semiconductor device 100 in the bulk doping region 18 compared to the first high concentration region 304. However, in the first high concentration region 304, the equipotential surface 308 spreads less in the depth direction and the outer periphery direction of the semiconductor substrate 10 compared to the equipotential surface 310. This is because the donor concentration of the first high concentration region 304 is higher than the bulk donor concentration. As a result, the spread of the equipotential surface 308 in the bulk doping region 18 toward the outer periphery can be made significantly narrower than the equipotential surface 310.

[0146] When second high concentration region 202 and first high concentration region 304 are provided, the doping concentration of second high concentration region 202 is higher than that of bulk doping region 18. Therefore, equipotential surface 306 is less likely to spread toward the outer periphery of semiconductor device 100 than equipotential surface 308. As a result, equipotential surface 306 is closer to well region 11 than equipotential surface 308. This makes it possible to prevent the depletion layer in edge termination structure 90 from spreading too far in the lateral direction. Therefore, the length of edge termination structure 90 in the outer periphery can be shortened, and the area of ​​top surface 21 of semiconductor device 100 can be reduced.

[0147] Fig. 7 shows another example of the carrier concentration distribution, donor concentration distribution, and defect density distribution in the dd line shown in Fig. 4. The second high concentration region 202 in this example is formed by injecting hydrogen from the upper surface 21 of the semiconductor substrate 10. That is, the second high concentration region 202 contains hydrogen donors such as VOH defects. The distributions other than the second high concentration region 202 are the same as the example in Fig. 5.

[0148] The hydrogen concentration distribution in the second high concentration region 202 has a maximum value at a first peak 318. Because hydrogen is implanted from the upper surface 21 of the semiconductor substrate 10, a slope 324 of the hydrogen concentration distribution on the lower surface 23 side of the first peak 318 is steeper than a slope 326 of the hydrogen concentration distribution on the upper surface 21 side of the first peak 318.

[0149] In the second high concentration region 202, the VOH defect density distribution may be similar to the hydrogen concentration distribution. For example, the positions of inflection points such as maximum, minimum, and kink of each distribution may be located at approximately the same depth position. The VOH defect density distribution may have a flat portion 327 with approximately uniform density on the upper surface 21 side of the first peak 318 of the hydrogen concentration distribution. In another example, the VOH defect density in the second high concentration region 202 may gradually decrease toward the upper surface 21 side, similar to the slope 326 of the hydrogen concentration distribution.

[0150] The carrier concentration distribution in this example has a peak 314 at the same depth as the first peak 318 of the hydrogen concentration distribution in the second high concentration region 202. Between the peaks 312 and 314, there is a bulk donor concentration N B The base carrier concentration N 00 The carrier concentration distribution may have a plateau 317 between the peak 314 and the upper surface 21, where the carrier concentration is approximately uniform.

[0151] The flat portion 317 may have a carrier concentration varying in a range of not less than the minimum value N0 of the carrier concentration between the peak 314 and the upper surface 21 and not more than twice the minimum value N0. The flat portion 317 may have a carrier concentration varying in a range of not less than the minimum value N0 and not more than 1.5 times the minimum value N0, or may have a carrier concentration varying in a range of not less than the minimum value N0 and not more than 1.2 times the minimum value N0. Similarly, the flat portion 327 may have a VOH defect density varying in a range of not less than the minimum value of the VOH defect density between the first peak 318 of the hydrogen concentration distribution and the upper surface 21 and not more than twice the minimum value. The flat portion 327 may have a VOH defect density varying in a range of not less than the minimum value and not more than 1.5 times the minimum value, or may have a VOH defect density varying in a range of not less than the minimum value and not more than 1.2 times the minimum value. The second high concentration region 202 may have a carrier concentration gradually decreasing from the peak 314 toward the upper surface 21.

[0152] The carrier concentration at the peak 314 of the second high concentration region 202 may be the same as or different from the carrier concentration at the peak 312 of the first high concentration region 304. The carrier concentration at the peak 314 of the second high concentration region 202 is greater than the minimum value N0 of the carrier concentration in the second high concentration region 202. The carrier concentration at the peak 314 may be two or more times, five or more times, or ten or more times the minimum value N0. The carrier concentration at the peak 314 is greater than the base carrier concentration N 00 It may be 10 times or more, or may be 100 times or more.

[0153] Fig. 8 is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the example shown in Fig. 4 in the depth range in which the first high concentration region 304 is provided. The position in the depth direction of the hydrogen peak part 302 may also differ from the example shown in Fig. 4. The other structures are the same as the example shown in Fig. 4.

[0154] The first high concentration region 304 in this example is in contact with the guard ring 92. The first high concentration region 304 is in contact with at least the lower end of the guard ring 92. The first high concentration region 304 may also be provided between two adjacent guard rings 92. The first high concentration region 304 in this example is not in contact with the second high concentration region 202. The first high concentration region 304 may be provided on the upper surface 21 side of the bottom surface of the trench portion. That is, the first high concentration region 304 may be provided up to the mesa portion sandwiched between the adjacent trench portions. A bulk doping region 18 having a bulk donor concentration may be provided between the first high concentration region 304 and the second high concentration region 202.

[0155] The hydrogen peak portion 302 in this example may not be in contact with the guard ring 92. In other words, the hydrogen peak portion 302 may be disposed below the guard ring 92. In another example, the hydrogen peak portion 302 may be in contact with the guard ring 92. The first high concentration region 304 may reach the upper surface 21.

[0156] According to this example, since the lower end of the guard ring 92 is covered with the first high concentration region 304, it is possible to reduce the variation in donor concentration in the region where the electric field is likely to concentrate, and therefore it is possible to further reduce the variation in the breakdown voltage.

[0157] Fig. 9 is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the example shown in Fig. 4 or 8 in the depth range in which the second high concentration region 202 and the first high concentration region 304 are provided. The other structure is the same as the example shown in Fig. 4 or 8.

[0158] In this example, a portion of the second high concentration region 202 and a portion of the first high concentration region 304 are provided in the same region. The lower end of the second high concentration region 202 is located within the range of the first high concentration region 304, and the upper end of the first high concentration region 304 is located within the range of the second high concentration region 202. With this configuration, the second high concentration region 202 and the first high concentration region 304 are connected, making it possible to reduce the region of bulk donor concentration in the edge termination structure 90. This makes it possible to further reduce variations in breakdown voltage.

[0159] The second high concentration region 202 may be formed to a position deeper than the lower end of the guard ring 92. This allows the second high concentration region 202 and the first high concentration region 304 to be easily connected. In another example, the second high concentration region 202 may be formed to a position shallower than the lower end of the guard ring 92. The hydrogen peak portion 302 in this example is disposed within the second high concentration region 202. The hydrogen peak portion 302 may be provided at a position in contact with the guard ring 92. This allows the first high concentration region 304 to be formed close to the upper surface 21, allowing the second high concentration region 202 and the first high concentration region 304 to be easily connected.

[0160] In edge termination structure 90, bulk doping region 18 of bulk donor concentration may remain outside guard ring 92 arranged at the outermost position, or second high concentration region 202 may be provided instead. In this example, no bulk doping region 18 remains. In the example of FIG. 9, second high concentration region 202 does not cover a portion of the lower end of guard ring 92. As shown by the dashed line in FIG. 9, second high concentration region 202 may cover the entire guard ring 92. First high concentration region 304 may reach upper surface 21.

[0161] Fig. 10 is a diagram showing an example of hydrogen concentration distribution on the ee line of Fig. 9. Fig. 10 shows the chemical concentration distribution of hydrogen. In this example, the second high concentration region 202 is formed of a hydrogen donor, but the second high concentration region 202 may be formed of a donor other than hydrogen, such as phosphorus.

[0162] In this example, a first peak 318 in the hydrogen concentration distribution due to hydrogen implanted from the upper surface 21 overlaps with a hydrogen peak portion 302 in the hydrogen concentration distribution due to hydrogen implanted from the lower surface 23. "Peaks overlap" means that the apex of one peak is included within the range of the full width at half maximum of the other peak.

[0163] The hydrogen concentration distribution may have a single peak at a position where the second high concentration region 202 and the first high concentration region 304 overlap, where the first peak 318 and the hydrogen peak portion 302 overlap. The hydrogen concentration distribution may gradually decrease from the peak to the upper surface 21, and gradually decrease from the peak to the buffer region 20.

[0164] Moreover, the carrier concentration distribution in this example may have a single peak at the depth position of the first peak 318 and the hydrogen peak portion 302. The carrier concentration distribution may have a flat portion 317 (see FIG. 7) on the upper surface 21 side of the peak, and a flat portion 313 (see FIG. 7) on the lower surface 23 side of the peak.

[0165] Moreover, the VOH defect density distribution of this example may have a single peak at the depth position of the first peak 318 and the hydrogen peak portion 302. The VOH defect density distribution may have a flat portion 327 (see FIG. 7) on the upper surface 21 side of the peak, and a flat portion 323 (see FIG. 7) on the lower surface 23 side of the peak.

[0166] Fig. 11 is a diagram showing another example of the hydrogen concentration distribution in the ee line of Fig. 9. Fig. 11 shows the chemical concentration distribution of hydrogen. In this example, the second high concentration region 202 is formed of a hydrogen donor, but the second high concentration region 202 may be formed of a donor other than hydrogen, such as phosphorus.

[0167] In this example, a first peak 318 in the hydrogen concentration distribution due to hydrogen implanted from the upper surface 21 and a hydrogen peak portion 302 in the hydrogen concentration distribution due to hydrogen implanted from the lower surface 23 are located apart from each other. However, the first peak 318 is located at a position overlapping with the first high concentration region 304, and the hydrogen peak portion 302 is located at a position overlapping with the second high concentration region 202. In other words, the hydrogen peak portion 302 is located between the first peak 318 and the upper surface 21 of the semiconductor substrate 10.

[0168] Slope 326 of first peak 318 on the upper surface 21 side is gentler than slope 324 on the lower surface 23 side. Also, slope 320 of hydrogen peak 302 on the lower surface 23 side is gentler than slope 322 on the upper surface 21 side. That is, in first peak 318 and hydrogen peak 302, relatively gentle slopes (slope 326 and slope 320) are arranged opposite each other.

[0169] Moreover, the carrier concentration distribution of this example may have peaks (peak 314 and peak 312 in FIG. 7) at the depth positions of the first peak 318 and the hydrogen peak portion 302, respectively. The carrier concentration distribution may have a flat portion 317 (see FIG. 7) on the upper surface 21 side of the peak 312, and a flat portion 313 (see FIG. 7) on the lower surface 23 side of the peak 314.

[0170] Furthermore, the VOH defect density distribution of this example may have peaks at the depth positions of the first peak 318 and the hydrogen peak portion 302. Of the two peaks, the VOH defect density distribution may have a flat portion 327 (see FIG. 7) located further toward the upper surface 21 than the peak on the upper surface side, and may have a flat portion 323 (see FIG. 7) located further toward the lower surface 23 than the peak on the lower surface side.

[0171] FIG. 12 is a diagram showing another example of the cc cross section in FIG. 1. In the semiconductor device 100 of this example, the arrangement of the high concentration regions in at least a part of region 91 of the edge termination structure 90 is different from the examples shown in FIG. 4, FIG. 8 or FIG. 9. In addition, in region 91, a third high concentration region 203 may be provided instead of the second high concentration region 202. The third high concentration region 203 is a high concentration region formed to a position deeper than the second high concentration region 202. In region 91, one or more of the bulk doping region 18, the second high concentration region 202, the first high concentration region 304 and the third high concentration region 203 may be provided. The other structure is the same as the example shown in FIG. 4, FIG. 8 or FIG.

[0172] The first high concentration region 304 in the example of FIG. 12 is not provided in a region 91 of a predetermined width in the edge termination structure 90 that contacts the edge 102 of the semiconductor substrate 10. The region 91 may include one or more guard rings 92. A bulk doping region 18 of a bulk donor concentration may be provided in the region 91 instead of the first high concentration region 304. The first high concentration region 304 does not have to be formed in the edge termination structure 90. The outer peripheral end of the first high concentration region 304 may be located on the inner side of the innermost guard ring 92. In another example, the first high concentration region 304 may also be provided in the region 91. The first high concentration region 304 in the region 91 may have the same length in the Z axis direction as the first high concentration region 304 disposed on the inside of the region 91, or the length may be shorter or longer.

[0173] The edge termination structure 90 inside region 91 has the same structure as the example shown in Figure 4, Figure 8 or Figure 9. The edge termination structure 90 inside region 91 includes one or more guard rings 92. As shown in Figure 4, 8 or 9, the first high concentration region 304 may be provided in a range that includes the bottom end of the guard ring 92, or may be provided in a range that does not include the bottom end of the guard ring 92.

[0174] The region 91 may or may not include the second high concentration region 202. Alternatively, instead of the second high concentration region 202, an N-type third high concentration region 203 having a donor concentration higher than the bulk donor concentration may be provided. The donor concentration of the third high concentration region 203 may be the same as or different from the donor concentration of the second high concentration region 202. The third high concentration region 203 is provided from the upper surface 21 of the semiconductor substrate 10 to a position deeper than the lower end of the second high concentration region 202. The third high concentration region 203 of this example may be provided to a position deeper than the lower end of the guard ring 92. A bulk doping region 18 is provided between the third high concentration region 203 and the buffer region 20.

[0175] The third high concentration region 203 may be formed by implanting a donor such as phosphorus or hydrogen from the upper surface 21. The implantation depth of the donor in the third high concentration region 203 may be deeper than the implantation depth of the donor in the second high concentration region 202. The heat treatment for the second high concentration region 202 and the third high concentration region 203 may be performed separately or commonly.

[0176] Fig. 13 is an enlarged cross-sectional view of the well region 11 and the vicinity of the guard ring 92. An XZ cross section is shown in Fig. 13. Fig. 13 also shows the well region 11 and the guard ring 92, and omits configurations such as the second high concentration region 202, the bulk doping region 18, the first high concentration region 304, and the hydrogen peak portion 302.

[0177] In FIG. 13, the distance between point 330 in the well region 11 and point 332 in the guard ring 92-1 closest to the well region 11 is defined as D2. Point 330 is the point in the well region 11 that is closest to the guard ring 92-1 on the upper surface 21 of the semiconductor substrate 10. Point 332 is the point in the guard ring 92-1 that is farthest from point 330. In other words, distance D2 is the maximum value of the distance between point 330 in the well region 11 and each point in the guard ring 92-1 closest to the well region 11. The distance in the Z-axis direction between the hydrogen peak portion 302 and the second high concentration region 202 shown in FIG. 4 and the like is defined as D1. Distance D1 is the distance between the apex of the peak of the carrier concentration in the second high concentration region 202 and the apex of the hydrogen peak portion 302 as shown in FIG. 5 and FIG. 7. Distance D1 may be smaller than distance D2. By reducing the distance D1, the region of bulk donor concentration can be reduced, and the variation in doping concentration can be suppressed.

[0178] The distance between point 330 in well region 11 and point 334 in guard ring 92-1 is defined as D3. Point 334 is the point of guard ring 92-1 that is the farthest from well region 11 on top surface 21 of semiconductor substrate 10. Distance D1 may be smaller than distance D3.

[0179] The distance between point 330 in well region 11 and point 336 in guard ring 92-1 is defined as D4. Point 336 is the lowest point in guard ring 92-1. Point 336 may be the lower end of guard ring 92-1 at the center in the X-axis direction. Distance D1 may be smaller than distance D4.

[0180] The distance between point 330 in well region 11 and point 338 in guard ring 92-1 is defined as D5. Point 338 is the point of guard ring 92-1 that is closest to well region 11 on top surface 21 of the semiconductor substrate. Distance D1 may be smaller than distance D5.

[0181] 14 is a diagram showing another structural example of the second high-concentration region 202. In this example, the position of the lower end of the guard ring 92 in the Z-axis direction is designated as Z1.

[0182] The second high concentration region 202 has a region located closer to the upper surface 21 than position Z1, and a region located closer to the lower surface 23 than position Z1. The second high concentration region 202 in this example is provided continuously from position Z0, where it contacts the upper surface 21 of the semiconductor substrate 10, to depth position Z2. Position Z2 is a position farther from the upper surface 21 than position Z1.

[0183] In this example, second high concentration region 202 covers a part of guard ring 92 when viewed from the lower surface 23 side of semiconductor substrate 10. That is, in the Z-axis direction, a part of second high concentration region 202 overlaps a part of guard ring 92. A region of second high concentration region 202 located between depth positions Z1 and Z2 may cover a part of guard ring 92. This makes it possible to alleviate electric field concentration near the lower end of guard ring 92.

[0184] FIG. 14 shows a schematic diagram of an equipotential surface 262. As shown in FIG. 14, an electric field may concentrate near a lower region 260 of the guard ring 92. The lower region 260 may be a region where the curvature of the boundary between the guard ring 92 and the N-type region is maximum. The lower region 260 may be a region where the change in the slope of the boundary between the guard ring 92 and the N-type region (i.e., the second-order differential value) is maximum. The lower region 260 is disposed near the lower end of the guard ring 92. The lower end of the guard ring 92 is the part of the guard ring 92 that is disposed at the deepest position.

[0185] Note that guard ring 92 may have lower region 260 and lower region 261. When the cross-sectional shape of guard ring 92 is line-symmetrical with respect to a center line parallel to the Z-axis, guard ring 92 has lower region 260 and lower region 261 at line-symmetrical positions. Of the two lower regions 260, the one closer to well region 11 is referred to as lower region 261, and the one farther from well region 11 is referred to as lower region 260. As shown in FIG. 14, an electric field is likely to concentrate near lower region 260.

[0186] By providing the second high concentration region 202, a high concentration N-type region can be arranged in the vicinity of the lower region 260 and the lower region 261. This makes it possible to suppress the spread of a depletion layer while mitigating electric field concentration in the vicinity of the lower region 260 and the lower region 261. The second high concentration region 202 preferably covers the lower region 260. In other words, the second high concentration region 202 preferably contacts the lower region 260. The second high concentration region 202 may further cover the lower region 261. The cross-sectional shape of the second high concentration region 202 may be symmetrical with respect to a center line parallel to the Z axis.

[0187] In addition, since the electric field is concentrated in the area between the guard rings 92 and in the area near the lower end of the guard rings 92, if the donor concentration in the area varies, the breakdown voltage will vary. If the second high concentration area 202 is not provided, the bulk doping area 18 is formed in the area. The donor concentration in the bulk doping area 18 is the concentration of the donor contained in the semiconductor substrate 10 from the time of manufacture, so it is relatively easy to vary. In contrast, in this example, the second high concentration area 202 is provided in the area. The second high concentration area 202 is formed by ion implantation or the like. Since the concentration of the ion implantation is relatively easy to control, the variation in the donor concentration in the second high concentration area 202 is relatively small. Therefore, by providing the second high concentration area 202, the variation in the breakdown voltage of the semiconductor device 100 can be reduced.

[0188] The second high concentration region 202 is provided in at least one of the regions sandwiched between the guard rings 92. The second high concentration region 202 may be disposed in all of the regions sandwiched between the guard rings 92.

[0189] Each guard ring 92 may have a region 204 that is not covered by the second high concentration region 202 when viewed from the lower surface 23 side of the semiconductor substrate 10. Region 204 may be a region that includes the lower end of the guard ring 92 at the center in the X-axis direction. Region 204 may be in contact with the bulk doping region 18. Region 204 may be in contact with the first high concentration region 304.

[0190] A width W2 of region 204 in the X-axis direction is smaller than a width W1 of guard ring 92 on upper surface 21 of semiconductor substrate 10. Width W2 may be 10% or more of width W1, 30% or more, 50% or more, or 70% or more.

[0191] FIG. 15 is a diagram showing another example of the second high concentration region 202. The structure other than the second high concentration region 202 is the same as the example shown in FIG. 14. The second high concentration region 202 of this example has an upper portion 206 and a lower portion 208. The upper portion 206 and the lower portion 208 are provided separately from each other. In this example, a bulk doping region 18 with a bulk donor concentration is provided between the upper portion 206 and the lower portion 208. When an N-type dopant is injected from the upper surface 21 to the lower portion 208, a donor may be formed in the region through which the N-type dopant has passed. In this case, the donor concentration gradually decreases from the lower portion 208 to the upper surface 21. Between the lower portion 208 and the upper portion 206, the donor concentration may gradually decrease from the lower portion 208 to the upper portion 206. For example, when hydrogen is used as an N-type dopant, vacancy defects (V) formed in the region through which hydrogen has passed combine with oxygen (O) contained in the semiconductor substrate 10 and hydrogen (H) diffused from the lower portion 208 to form VOH defects. The VOH defects function as donors.

[0192] The upper portion 206 is provided between the two guard rings 92 and in contact with the upper surface 21 of the semiconductor substrate 10. The upper portion 206 may be disposed away from the guard rings 92. This makes it possible to suppress the donors doped at a high concentration in the upper portion 206 from diffusing into the guard rings 92. In another example, the upper portion 206 may be in contact with the guard ring 92. The upper portion 206 may have a portion that does not overlap with the field plate 94 shown in FIG. 4 and the like. The upper portion 206 may be provided so as to overlap the entire gap between two adjacent field plates 94.

[0193] The lower portion 208 is provided from a position shallower than the lower end of the guard ring 92 to a position Z2 deeper than the lower end of the guard ring 92. The lower portion 208 of this example is provided in contact with the side 93-2 of the guard ring 92 that is farther from the well region 11 than the two side surfaces 93-1 and 93-2. The side surface 93-1 of the guard ring 92 in FIG. 5 is the surface closer to the well region 11 than the center of the guard ring 92 in the X-axis direction. The side surface 93-2 of the guard ring 92 is the surface on the opposite side to the side surface 93-1. The lower portion 208 may not be in contact with the side surface 93-1, or may be in contact with it. By providing the lower portion 208 in contact with the side surface 93-2, it is possible to protect a region where an electric field is likely to concentrate. The lower portion 208 is preferably in contact with the lower region 260. Moreover, the width W2 of the region 204 of this example is larger than half the width W1 of the guard ring 92.

[0194] The position in the Z-axis direction of the upper end of the lower portion 208 is designated as Z3. The distance Z1-Z3 between the positions Z1 and Z3 in the Z-axis direction may be the same as the distance Z2-Z1 between the positions Z1 and Z2 in the Z-axis direction. The distance Z2-Z1 may be greater than the distance Z1-Z3. This makes it easier to protect an area where an electric field is likely to concentrate. The distance Z2-Z1 may be less than the distance Z1-Z3.

[0195] Also, multiple types of N-type dopants may be used to form the second high concentration region 202. For example, a first dopant such as phosphorus may be implanted to form the upper portion 206, and a second dopant such as hydrogen may be implanted to form the lower portion 208. In this case, the upper portion 206 contains a higher concentration of the first dopant (phosphorus) than the second dopant (hydrogen), and the lower portion 208 contains a higher concentration of the second dopant (hydrogen) than the first dopant (phosphorus).

[0196] Furthermore, the dose of the N-type dopant implanted into the second high concentration region 202 may be adjusted according to the resistivity or donor concentration of the semiconductor substrate 10 before the implantation of the N-type dopant. This makes it possible to adjust the resistivity or donor concentration of the semiconductor substrate 10 after the second high concentration region 202 is formed with greater precision.

[0197] 16A and 16B are diagrams illustrating a part of the manufacturing process of semiconductor device 100. FIG. 16A and FIG. 16B show a process of forming lower portion 208 of second high concentration region 202. In this example, N-type dopants are implanted into lower portion 208 using electrodes such as field plate 94, peripheral gate wiring 130, and emitter electrode 52 as masks. In edge termination structure 90, N-type dopants are implanted through gaps 95 between adjacent field plates 94.

[0198] In this example, an N-type dopant is implanted after the interlayer insulating film 38, the field plate 94, and other electrodes are formed. The N-type dopant is, for example, hydrogen. Alternatively, an N-type dopant may be implanted into the lower portion 208 after the well region 11, the upper portion 206, and the guard ring 92 are formed. After the lower portion 208 is formed by implanting the N-type dopant, a protective film such as a polyimide or nitride film may be formed above the field plate 94, the peripheral gate wiring 130, and the emitter electrode 52, and other electrodes.

[0199] According to this example, since field plate 94 is used as a mask, it is possible to simplify the manufacturing process of semiconductor device 100. In this example, at least a part of the region of lower portion 208 overlaps with gap 95 in the Z-axis direction. In lower portion 208, a region where the donor concentration is maximum may overlap with gap 95 in the Z-axis direction.

[0200] Field plate 94 may overlap a portion of lower portion 208 in the Z-axis direction. N-type dopants implanted into lower portion 208 diffuse in the X-axis direction to form a portion of lower portion 208 at a position overlapping field plate 94. Field plate 94 may overlap a portion or the entire region of upper portion 206.

[0201] The central position of field plate 94 in the X-axis direction is designated as X1, and the central position of guard ring 92 in the X-axis direction is designated as X2. Central position X1 of field plate 94 may be located closer to well region 11 than central position X2 of guard ring 92. This makes it easier to form the lower portion in lower region 260 without forming lower portion 208 in lower region 261 shown in FIG.

[0202] In this example, the position of the lower end of the well region 11 in the Z-axis direction is Z4. In FIG. 16A, the position Z1 of the lower end of the guard ring 92 coincides with the position Z4 of the lower end of the well region 11. That is, the lower portion 208 is disposed in a region deeper than the well region 11. On the other hand, in FIG. 16B, the position Z4 of the lower end of the well region 11 is disposed in a position deeper than the position Z1 of the lower end of the guard ring 92. Also, in FIG. 16B, the position Z2 of the lower end of the lower portion 208 is disposed closer to the upper surface 21 than the position Z4 of the lower end of the well region 11. That is, the lower portion 208 is disposed in a region shallower than the well region 11. Also, in both FIG. 16A and FIG. 16B, the doping concentration of the lower portion 208 is lower than the doping concentration of the well region 11.

[0203] 17A and 17B are cross-sectional views in the vicinity of the emitter electrode 52 and the peripheral gate wiring 130. FIG. 17A corresponds to the example of FIG. 16A, and FIG. 17B corresponds to the example of FIG. 16B. That is, the depth position Z4 of the well region 11 in FIG. 17A is the same as that in the example shown in FIG. 16A, and the depth position Z4 of the well region 11 in FIG. 17B is the same as that in the example shown in FIG. 16B. In FIGS. 17A and 17B, the structure of the trench and the like is simplified, and the contact hole in the interlayer insulating film 38 is omitted. A gap 95 is provided between the emitter electrode 52 and the peripheral gate wiring 130.

[0204] If an N-type dopant is injected using the electrodes, such as the field plate 94, the peripheral gate wiring 130, and the emitter electrode 52, as a mask, the N-type dopant will also be injected from the gap 95 between the peripheral gate wiring 130 and the emitter electrode 52. In Figures 17A and 17B, the region into which the N-type dopant is injected is designated as region 209. Region 209 is located at the same depth as lower portion 208 shown in Figures 16A and 16B, etc.

[0205] Well region 11 is formed below gap 95. For this reason, when well region 11 and guard ring 92 are aligned at their lower ends as in Fig. 16A, if lower portion 208 is disposed at a position deeper than well region 11, lower portion 208 is formed to protrude from the lower end of well region 11 as in Fig. 17A.

[0206] On the other hand, as shown in FIG. 16B, when the position Z4 of the lower end of the well region 11 is deeper than the position Z1 of the lower end of the guard ring 92, the lower portion 208 is arranged in a region shallower than the well region 11, so that the lower portion 208 does not protrude from the lower end of the well region 11 as shown in FIG. 17B. In this case, the position Z4 of the lower end of the well region 11 is farther from the upper surface 21 of the semiconductor substrate 10 than the position Z2 of the lower end of the guard ring 92. That is, the well region 11 is provided deeper than the guard ring 92. This allows the lower portion 208 to be formed deeper than the guard ring 92 while being shallower than the well region 11. In the examples of FIG. 16A and FIG. 17A, a mask for decelerating or shielding ions may be provided at a position covering the gap 95 above the well region 11. This also allows the lower portion 208 to not protrude from the lower end of the well region 11.

[0207] In addition, if the doping concentration of the lower portion 208 is higher than that of the well region 11, the conductivity type of the region 209 in Figures 17A and 17B will be inverted from P type to N type. This may result in a PN junction being formed at an unintended position, causing the characteristics of the semiconductor device 100 to fluctuate.

[0208] In contrast, the doping concentration of the lower portion 208 is made lower than the doping concentration of the well region 11, thereby preventing the conductivity type of the region 209 from becoming N-type. The doping concentration of the well region 11 may be higher than, the same as, or lower than the doping concentration of the guard ring 92. The doping concentration of the guard ring 92 is 1.0×10 17 atoms / cm 3 It may be the following:

[0209] 16A to 17B, an example has been described in which ion implantation is performed using field plate 94 as a mask in lower portion 208. In another example, after a protective film such as polyimide is formed above field plate 94 etc., ion implantation may be performed using the protective film as a mask.

[0210] Figures 18 and 19 are diagrams showing an example of ion implantation using protective film 140 as a mask. Figure 18 is a diagram showing another example of a cross section in the vicinity of edge termination structure 90. Figure 19 is a diagram showing another example of a cross section in the vicinity of emitter electrode 52 and peripheral gate wiring 130.

[0211] 18, the protective film 140 has an opening 98 above the lower portion 208. The opening 98 passes through a gap 95 in the field plate 94. Neither the protective film 140 nor the field plate 94 is provided at the position where the opening 98 and the gap 95 overlap. In this example, an N-type dopant is implanted into the region of the lower portion 208 through the opening 98 and the gap 95. At this time, as shown in FIG. 19, by not providing an opening in the protective film 140 above the well region 11, it is possible to prevent ions from being implanted into the well region 11.

[0212] Alternatively, instead of the protective film 140, a mask pattern may be formed using photoresist or the like to perform N-type dopant implantation. Alternatively, when performing ion implantation of the lower portion 208 using the gaps in the field plate 94 above the guard ring 92 as a mask, the gaps 95 in the field plate 94 above the well region 11 may be covered with resist. In this case, ions may be prevented from being implanted into the semiconductor substrate 10 by being shielded by the resist, or the region 209 may be made shallower by being slowed down by the resist so as not to protrude below the well region 11. Note that a recess may be used instead of the opening 98. The recess may be formed by etching the protective film 140, or may be formed during deposition of the protective film 140. When the protective film 140 is a nitride film or the like, a recess reflecting the presence or absence of the gaps 95 in the field plate 94 may be formed during deposition.

[0213] FIG. 20 is a diagram showing another example of the cc cross section in FIG. 1. The semiconductor device 100 of this example is different from the semiconductor device 100 described in FIG. 1 to FIG. 19 in the range in the XY plane where the first high concentration region 304 is provided. The range in the XY plane where the hydrogen peak portion 302 is provided may also be different from the examples described in FIG. 1 to FIG. 19. The structure other than the first high concentration region 304 and the hydrogen peak portion 302 may be the same as any of the embodiments described in FIG. 1 to FIG. 19. In FIG. 20, the arrangement of the first high concentration region 304 and the hydrogen peak portion 302 is different from the example shown in FIG. 4. Also, in the example shown in FIG. 20, the second high concentration region 202 is not provided, as compared with the example shown in FIG. 4. The other structure is the same as the example shown in FIG. 4.

[0214] In this example, at least a portion of the first high concentration region 304 is provided in the edge termination structure 90, and is provided in a range that does not reach the active section 160. The first high concentration region 304 may be provided only in the edge termination structure 90, or may be provided from the edge termination structure 90 to below the well region 11. In the example of FIG. 20, the first high concentration region 304 is provided from the end of the semiconductor substrate 10 in the X-axis direction to below the well region 11. The first high concentration region 304 may reach the upper surface 21.

[0215] The first high concentration region 304b may be provided so as to include at least the active portion 160, or so as to include only the active portion 160. The first high concentration region 304b may include the first high concentration region 304 in a plan view (upper surface 21 or lower surface 23) or in the depth direction of the semiconductor substrate 10. The upper end of the first high concentration region 304b may be located in a region between the lower end of each trench portion and the lower surface 23, may reach between each trench portion and the upper surface 21, or may reach the upper surface 21. The doping concentration of the first high concentration region 304b may be lower than the doping concentration of the first high concentration region 304.

[0216] In this example, the first high concentration region 304 is not provided in the active section 160, and therefore it is possible to prevent a change in the characteristics of the active section 160 due to the provision of the first high concentration region 304. Since the edge termination structure 90 is provided with the first high concentration region 304, it is possible to suppress the spread of the depletion layer in the edge termination structure 90 and to reduce the area of ​​the edge termination structure 90 in the XY plane.

[0217] FIG. 21 is a diagram showing another example of the cc cross section in FIG. 1. The semiconductor device 100 of this example differs from the example described in FIG. 20 in that a second high concentration region 202 is provided. The other structures are the same as those of the semiconductor device 100 of any of the aspects described in FIG. 20. In this example as well, it is possible to suppress the spread of the depletion layer in the edge termination structure 90 while preventing the characteristic fluctuation of the active section 160. The first high concentration region 304 may reach the upper surface 21. In this example as well, a first high concentration region 304b may be provided, as in the example of FIG. 20.

[0218] FIG. 22 is a diagram showing another example of the cc cross section in FIG. 1. In the semiconductor device 100 of this example, the upper end position in the Z-axis direction of the first high concentration region 304 and the position in the Z-axis direction of the hydrogen peak portion 302 are different from those of the example described in FIG. 20 or FIG. 21. The other structures are the same as those of either of the examples described in FIG. 20 or FIG. 21. In the example shown in FIG. 22, the second high concentration region 202 is provided as in the example of FIG. 21. In addition, the upper end position in the Z-axis direction of the first high concentration region 304 and the position in the Z-axis direction of the hydrogen peak portion 302 are the same as those of the example described in FIG. 8. The first high concentration region 304 may reach the upper surface 21. In this example, the first high concentration region 304b may be provided as in the example of FIG. 20. In this example, the spread of the depletion layer in the edge termination structure 90 can be suppressed while preventing the characteristic fluctuation of the active portion 160.

[0219] FIG. 23 is a diagram showing another example of the cc cross section in FIG. 1. In the semiconductor device 100 of this example, the structure of the second high concentration region 202 is different from that of the example shown in FIG. 22. The other structures are the same as those of the example shown in FIG. 22. The second high concentration region 202 of this example has the same structure as that of the example shown in FIG. 9. The first high concentration region 304 may reach the upper surface 21. This example may also have the first high concentration region 304b, as in the example of FIG. 20. This example also makes it possible to suppress the spread of the depletion layer in the edge termination structure 90 while preventing the characteristics of the active section 160 from fluctuating.

[0220] Fig. 24A is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the semiconductor device 100 described with reference to Figs. 20 to 23 in that the first high concentration region 304 has a plurality of regions with different lengths in the Z-axis direction. In addition, the position of the hydrogen peak part 302 in the Z-axis direction also differs in each region of the first high concentration region 304. The other structure is the same as any of the examples described with reference to Figs. 20 to 23.

[0221] The first high concentration region 304 has an inner portion and an outer portion provided outside the inner portion. The outer portion refers to the side farther from the active portion 160 in the XY plane. The outer portion has a length in the Z-axis direction greater than that of the inner portion. In the example of FIG. 24A, the first high concentration region 304 includes a first high concentration region 304-1, a first high concentration region 304-2, and a first high concentration region 304-3. The first high concentration region 304-2 is disposed outside the first high concentration region 304-1 and is provided longer in the Z-axis direction than the first high concentration region 304-1. The first high concentration region 304-3 is disposed outside the first high concentration region 304-2 and is provided longer in the Z-axis direction than the first high concentration region 304-2. In other words, when the first high concentration region 304-1 is defined as the inner portion, the first high concentration region 304-2 and the first high concentration region 304-3 are the outer portions. Moreover, if the first high concentration region 304-2 is an inner portion, the first high concentration region 304-3 is an outer portion. In this example, the length of each region of the first high concentration region 304 in the Z-axis direction changes stepwise.

[0222] An upper end of each of the first high concentration regions 304 may be disposed within the drift region 19. In another example, an upper end of the first high concentration region 304-3 may be disposed at a position overlapping with the guard ring 92 or the well region 11.

[0223] The hydrogen peak 302-2 included in the first high concentration region 304-2 is located higher in the Z-axis direction than the hydrogen peak 302-1 included in the first high concentration region 304-1. The hydrogen peak 302-3 included in the first high concentration region 304-3 is located higher in the Z-axis direction than the hydrogen peak 302-2 included in the first high concentration region 304-2. The first high concentration region 304-3 may reach the upper surface 21. This example may also have a first high concentration region 304b, as in the example of FIG. 20.

[0224] According to the semiconductor device 100 of this example, the first high concentration region 304 in the vicinity of the active portion 160 is short in the Z-axis direction, so that it is possible to suppress the influence of the first high concentration region 304 on the characteristics of the active portion 160. In addition, since the first high concentration region 304 away from the active portion 160 is long in the Z-axis direction, it is possible to suppress the spread of the depletion layer in the edge termination structure 90.

[0225] Fig. 24B is a diagram showing another example of the cc cross section in Fig. 1. In the semiconductor device 100 of this example, similar to the example of Fig. 24A, the first high concentration region 304 has a plurality of regions having different lengths in the Z-axis direction. The other structures are the same as any of the examples described in Fig. 20 to Fig. 23.

[0226] In this example, the height of the step of the first high concentration region 304 below the well region 11 (Z8 in this example) is greater than the height of the step of the first high concentration region 304 in the edge termination structure 90 (0 μm in this example). The upper end position of the first high concentration region 304 in the edge termination structure 90 may be constant. If there are multiple steps of the first high concentration region 304 in any region, the smallest step of the first high concentration region 304 below the well region 11 may be greater than the largest step of the first high concentration region 304 in the edge termination structure 90.

[0227] Furthermore, when the upper end position of the first high concentration region 304 changes continuously instead of stepwise, the slope of the upper end position of the first high concentration region 304 below the well region 11 is larger than the slope of the upper end position of the first high concentration region 304 in the edge termination structure 90. When the slope of the upper end position of the first high concentration region 304 changes in any region, the minimum value of the slope of the upper end position of the first high concentration region 304 below the well region 11 may be larger than the maximum value of the slope of the upper end position of the first high concentration region 304 in the edge termination structure 90. Note that the slope of the upper end position is, for example, the amount of change in the Z-axis position of the upper end of the first high concentration region 304 per unit length in the X-axis direction. According to this example, the Z-axis length of the first high concentration region 304 below the well region 11 and in the active portion 160 can be reduced, and the Z-axis length of the first high concentration region 304 in the edge termination structure 90 can be increased. This makes it possible to suppress avalanche breakdown from occurring on the upper surface side of the semiconductor substrate 10 in the well region 11 and the active portion 160. The first high concentration region 304-2 may reach the upper surface 21. This example may also have the first high concentration region 304b, as in the example of FIG.

[0228] Fig. 25A is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the semiconductor device 100 described with reference to Figs. 20 to 23 in that the first high concentration region 304 has a plurality of regions with different lengths in the Z-axis direction. In addition, the position of the hydrogen peak part 302 in the Z-axis direction also differs in each region of the first high concentration region 304. The other structure is the same as any of the examples described with reference to Figs. 20 to 23.

[0229] The first high concentration region 304 of this example differs from the first high concentration region 304 of FIG. 24A in that the length in the Z-axis direction gradually increases as it moves away from the active section 160. The other structures may be the same as those of the example of FIG. 24A. The hydrogen peak section 302 of this example is disposed on the upper side as it moves away from the active section 160. In this example as well, the upper end of the first high concentration region 304 may be entirely disposed within the drift region 19. In another example, a part of the upper end of the first high concentration region 304 may be disposed at a position overlapping with the guard ring 92 or the well region 11. In this example as well, the first high concentration region 304b may be provided as in the example of FIG. 20. In this example as well, the influence of the first high concentration region 304 on the characteristics of the active section 160 can be suppressed. In addition, the spread of the depletion layer in the edge termination structure section 90 can be suppressed.

[0230] Fig. 25B is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the example of Fig. 25A in that the first high concentration region 304 reaches the upper surface 21 in a region extending from the outer circumferential end of the semiconductor device 100 to a predetermined length toward the inner circumferential side in a plan view. The other structures are similar to the example of Fig. 25A.

[0231] Figure 26 is a diagram showing an example of a method for forming first high concentration region 304 described in Figure 24A. In this example, hydrogen ions are irradiated from the lower surface 23 side with a shielding member 350 disposed below the lower surface 23 of semiconductor substrate 10. Shielding member 350 covers the entire active portion 160 and at least a portion of edge termination structure 90. Shielding member 350 covering active portion 160 has a thickness sufficient to completely block hydrogen ions and prevent them from reaching semiconductor substrate 10.

[0232] The shielding member 350 covering the region where the first high concentration region 304 is to be provided has a thickness corresponding to the length in the Z-axis direction of each first high concentration region 304. That is, the longer the region where the first high concentration region 304 is to be formed, the thinner the shielding member 350. By making the shielding member 350 thinner, hydrogen ions can reach deeper into the semiconductor substrate 10, and the first high concentration region 304 becomes longer.

[0233] In this example, the shielding member 350 becomes thinner in a stepped manner as it moves away from the active portion 160. The shielding member 350 may or may not be provided below the first high concentration region 304-3. In FIG. 26, the collector electrode 24 is provided, but the lower surface 23 may be irradiated with hydrogen ions before the collector electrode 24 is formed. The hydrogen ion implantation of the first high concentration region 304b may be performed before or after the first high concentration region 304.

[0234] Fig. 27 is a diagram showing an example of a method for forming the first high concentration region 304 described in Fig. 25A or 25B. In this example, the shape of the shielding member 350 is different from the example in Fig. 26. The other conditions are the same as those in the example in Fig. 26.

[0235] In the present example, the shielding member 350 becomes thinner linearly or curvedly as it moves away from the active portion 160. The shielding member 350 may or may not be provided below the first high concentration region 304-3. The hydrogen ion implantation into the first high concentration region 304b may be performed before or after the first high concentration region 304.

[0236] 20 to 27, the resistivity (resistivity) of the first high concentration region 304 is lower than the resistivity of the drift region 19 in the active section 160 (transistor section 70 or diode section 80). The resistivity of the first high concentration region 304 may be 1 / 1.5 or less and 1 / 10 or more of the resistivity of the drift region 19 in the active section 160. The resistivity of the first high concentration region 304 may be 1 / 2 or less of the resistivity of the drift region 19 in the active section 160. The resistivity of each region may be the median value in the Z-axis direction of each region, or an average value.

[0237] 20 to 27, the resistivity of the drift region 19 of the active portion 160 may have a value according to the rated voltage of the semiconductor device 100. As an example, when the rated voltage is 600V, the resistivity may be 20 to 80 Ωcm, when the rated voltage is 1200V, the resistivity may be 40 to 120 Ωcm, when the rated voltage is 1700V, the resistivity may be 60 to 200 Ωcm, and when the rated voltage is 3300V, the resistivity may be 150 to 450 Ωcm.

[0238] In the embodiments shown in Figures 1 to 27, the semiconductor substrate 10 may have bulk acceptors of the second conductivity type distributed throughout. The bulk acceptors are acceptors that are uniformly introduced into the ingot during its manufacture, similar to the bulk donors. The bulk acceptors may be boron. The bulk acceptor concentration may be lower than the bulk donor concentration, i.e. the ingot is N-type. In one embodiment, the bulk acceptor concentration is 5 x 10 11 ( / cm 3 )~8×10 14 ( / cm 3 ) and the bulk donor concentration is 5×10 12 ( / cm 3 )~1×10 15 ( / cm 3 The bulk acceptor concentration may be 1% or more, 10% or more, or 50% or more of the bulk donor concentration. The bulk acceptor concentration may be 99% or less, 95% or less, or 90% or less of the bulk donor concentration.

[0239] The presence of bulk acceptors throughout the semiconductor substrate 10 makes it possible to reduce the net doping concentration in the semiconductor substrate 10 before implanting hydrogen ions or the like. This makes it possible to reduce the absolute value of the variation in the net doping concentration of the semiconductor substrate 10. This makes it easier to adjust the resistivity by implanting hydrogen ions.

[0240] Fig. 28 is a diagram showing another example of the cc cross section in Fig. 1. In the semiconductor device 100 of this example, the active portion 160 has an N-type fourth high concentration region 404. The structure other than the fourth high concentration region 404 is similar to that of the semiconductor device 100 of any of the aspects described with reference to Figs. 1 to 27. The first high concentration region 304 may reach the upper surface 21.

[0241] The fourth high concentration region 404 is provided from the upper surface 21 side to the lower surface 23 side of the semiconductor substrate 10, and has a donor concentration higher than the doping concentration of the bulk donor. The method of forming the fourth high concentration region 404 is similar to that of the first high concentration region 304. That is, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 to a predetermined depth position on the upper surface 21 side of the semiconductor substrate 10. By annealing the semiconductor substrate 10 after implanting the hydrogen ions, hydrogen donors are formed in the region through which the hydrogen ions have passed. As a result, the fourth high concentration region 404 is formed, which has a donor concentration higher than the bulk donor concentration.

[0242] The donor concentration of the fourth high concentration region 404 is different from the donor concentration of the first high concentration region 304. For example, the donor concentrations of these regions can be made different by making the dose of hydrogen ions into the active portion 160 and the dose of hydrogen ions into the edge termination structure 90 different. The implantation of hydrogen ions into the active portion 160 and the edge termination structure 90 may be performed in separate steps. Alternatively, after implanting hydrogen ions into the active portion 160 and the edge termination structure 90 in the same step with the same dose, additional hydrogen ions may be implanted into one of the active portion 160 and the edge termination structure 90.

[0243] In the example of FIG. 28, the donor concentration of the fourth high concentration region 404 is lower than the donor concentration of the first high concentration region 304. By making the donor concentration of the fourth high concentration region 404 lower than the donor concentration of the first high concentration region 304, it is possible to suppress the extension of the electric field in the vertical direction (Z-axis direction). Furthermore, by making the donor concentration of the fourth high concentration region 404 higher than the bulk donor concentration, it is possible to suppress the oscillation of the voltage or current waveform, for example, during switching of the semiconductor device 100. Furthermore, by making the donor concentration of the first high concentration region 304 higher than the donor concentration of the fourth high concentration region 404, it is possible to suppress the extension of the electric field in the horizontal direction and reduce the width of the edge termination structure 90 in the horizontal direction (X-axis direction and Y-axis direction). The donor concentration of the fourth high concentration region 404 may be 0.9 times or less, 0.5 times or less, or 0.1 times or less than that of the first high concentration region 304.

[0244] In the depth direction, the upper end position Z4 of the first high concentration region 304 and the upper end position Z5 of the fourth high concentration region 404 may be the same position or may be different. The upper end position Z5 of the fourth high concentration region 404 may be disposed below (toward the lower surface 23) or above (toward the upper surface 21) the upper end position Z4 of the first high concentration region 304. The boundary between the fourth high concentration region 404 and the first high concentration region 304 in the X-axis direction may be disposed below the well region 11. In another example, the boundary may be disposed in the active portion 160 or in the edge termination structure portion 90.

[0245] Fig. 29 is a diagram showing another example of the cc cross section in Fig. 1. In the semiconductor device 100 of this example, the donor concentration of the fourth high concentration region 404 is higher than the donor concentration of the first high concentration region 304. The other structures are similar to those of the semiconductor device 100 described in Fig. 28. The first high concentration region 304 may reach the upper surface 21.

[0246] According to this example, the donor concentration of the first high concentration region 304 is low in the edge termination structure 90, so that it is possible to suppress the occurrence of avalanche breakdown in the vicinity of the guard ring. The donor concentration of the fourth high concentration region 404 may be 1.1 times or more, 2 times or more, or 10 times or more that of the first high concentration region 304.

[0247] Fig. 30 is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example has a first high concentration region 304-4 and a first high concentration region 304-5 having different donor concentrations. The other structures are similar to those of the semiconductor device 100 described in Fig. 28 or 29. The first high concentration region 304-5 may reach the upper surface 21.

[0248] The first high concentration region 304-4 is the same as the first high concentration region 304 described in FIG. 28 or FIG. 29. The first high concentration region 304-5 is disposed between the first high concentration region 304-4 and the upper surface 21. The first high concentration region 304-5 may be in contact with the first high concentration region 304-4. The upper end position of the first high concentration region 304-5 may be the same as any of the first high concentration regions 304 described in FIG. 1 to FIG. 27. The upper end position of the first high concentration region 304-5 may be disposed above the upper end position Z5 of the fourth high concentration region 404.

[0249] The donor concentration of the first high concentration region 304-5 is lower than the donor concentration of the first high concentration region 304-4. The donor concentration of the first high concentration region 304-5 may be higher than, the same as, or lower than the donor concentration of the fourth high concentration region 404. For example, the structure of this example can be formed by performing a first step of implanting hydrogen ions into the active portion 160 and the edge termination structure 90 at the same depth position (Z5, Z6) with the same dose amount from the lower surface 23, and a second step of selectively implanting hydrogen ions into the edge termination structure 90 from the lower surface 23 to a position closer to the upper surface 21 than the depth position Z6. In the first step, at least one of the implantation depth and the dose amount of hydrogen ions into the active portion 160 and the edge termination structure 90 may be made different.

[0250] 31 is a diagram showing another example of the cc cross section in FIG. 1. In the semiconductor device 100 of this example, a first high concentration region 304 is also provided in the active section 160. In addition, in the active section 160, a P-type low concentration region 17 having a lower doping concentration than the base region 14 is provided between the base region 14 and the first high concentration region 304. The other structures are similar to those of the semiconductor device 100 of any of the aspects described in FIG. 1 to FIG. 30. The low concentration region 17 of this example is disposed between the accumulation region 16 and the first high concentration region 304 in a part of the active section 160 such as the transistor section 70, and functions as a part of the drift region 19.

[0251] The semiconductor substrate 10 of this example is a substrate in which hydrogen ions are implanted into an entirely P-type semiconductor substrate to form the first high concentration region 304 and the like, and more than half of the region is inverted to N-type. The doping concentration in the low concentration region 17 may be the same as the bulk acceptor concentration. The hydrogen donor concentration in the first high concentration region 304 is higher than the bulk acceptor concentration. In a portion of the active portion 160, hydrogen ions or phosphorus or the like may be implanted from the upper surface 21 of the semiconductor substrate 10 to form a fifth high concentration region 502 so as to be continuous with the first high concentration region 304. The fifth high concentration region 502 may be formed in various ways depending on the design.

[0252] In addition, in a region other than the active portion 160, the second high concentration region 202 may be provided between the first high concentration region 304 and the upper surface 21 of the semiconductor substrate 10. In the edge termination structure 90, the first high concentration region 304 and the second high concentration region 202 may be provided continuously. The second high concentration region 202 may be provided continuously from the upper end of the first high concentration region 304 to the upper surface 21 of the semiconductor substrate 10. The second high concentration region 202 can be formed by implanting hydrogen ions or phosphorus from the upper surface 21 of the semiconductor substrate 10, as described in FIG. 4 and the like. When the second high concentration region 202 is formed by implanting hydrogen ions, the hydrogen donor concentration in the second high concentration region 202 is higher than the bulk acceptor concentration. The second high concentration region 202 may also be provided below the well region 11. The second high concentration region 202 and the fifth high concentration region 502 may be formed simultaneously or separately. The second high concentration region 202 and the fifth high concentration region 502 may be formed so as to overlap with the first high concentration region 304. The second high concentration region 202 and the first high concentration region 304 do not have to be substantially uniform, and may be formed so as to have locally different concentrations or boundary positions.

[0253] A fifth high concentration region 502 may be provided between the well region 11 and the outer periphery of the transistor section 70 (in the +X-axis direction). That is, the low concentration region 17 of the transistor section 70 may be separated from the well region 11 by sandwiching the fifth high concentration region 502. Since the low concentration region 17 is of p-type, by separating it from the well region 11 so as not to be in contact with it, the low concentration region 17 becomes electrically floating.

[0254] Furthermore, a bottom high concentration region 170 of p type having a higher concentration than the low concentration region 17 may be provided so as to contact the bottom of one or more trench portions. The bottom high concentration region 170 may be provided continuously in the X-axis direction across a plurality of trench portions. The bottom high concentration region 170 may be separated from the well region 11 and may be electrically floating. The top surface 21 side of the bottom high concentration region 170 may contact the accumulation region 16 or may be separated from it. The bottom surface 23 side of the bottom high concentration region 170 may contact the low concentration region 17. The end of the bottom high concentration region 170 in the X-axis direction may be located inside the fifth high concentration region 502, may contact the fifth high concentration region 502, or may be separated from the fifth high concentration region 502. In this example, the end of the bottom high concentration region 170 in the X-axis direction is located inside the fifth high concentration region 502.

[0255] Figure 32 is a diagram showing another example of the cc cross section in Figure 1. In the semiconductor device 100 of this example, in the edge termination structure 90 etc., the first high concentration region 304 is provided above the lower end of the guard ring. The other structures are similar to those of the semiconductor device 100 described in Figure 31. In this example, the first high concentration region 304 is provided up to the upper surface 21 of the semiconductor substrate 10.

[0256] In this example, hydrogen ions may be implanted in the active portion 160 and the edge termination structure 90 in the same process via shielding members of different thicknesses, or in different processes. The acceleration energy of the hydrogen ions may be set for a portion of the edge termination structure 90 and the active portion 160 so that the hydrogen ions penetrate the semiconductor substrate 10. In addition, the first high concentration region 304 does not have to be substantially uniform, and may be formed so that the concentration or boundary position is locally different. In this example, an example in which the second high concentration region 202 is not provided has been described, but the second high concentration region 202 may be provided.

[0257] A first high concentration region 304 may be provided between the well region 11 and the outer periphery of the transistor section 70 (in the +X-axis direction). That is, the low concentration region 17 of the transistor section 70 may be separated from the well region 11 by sandwiching the first high concentration region 304. Since the low concentration region 17 is of p-type, by separating it from the well region 11 so as not to be in contact with it, it becomes electrically floating.

[0258] Furthermore, a bottom high concentration region 170 having a higher concentration than the low concentration region 17 and of p type may be provided so as to contact the bottom of one or more trench portions. The bottom high concentration region 170 may be provided continuously across a plurality of trench portions. The bottom high concentration region 170 may be separated from the well region 11 and may be electrically floating. The top surface 21 side of the bottom high concentration region 170 may contact the accumulation region 16 or may be separated from it. The bottom surface 23 side of the bottom high concentration region 170 may contact the low concentration region 17. The end of the bottom high concentration region 170 in the X-axis direction may be located inside the first high concentration region 304, may contact the first high concentration region 304, or may be separated from the first high concentration region 304. In this example, the end of the bottom high concentration region 170 in the X-axis direction is located inside the first high concentration region 304.

[0259] Fig. 33 is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the example shown in Fig. 4 in that the second high concentration region 202 is also disposed between the channel stopper 174 and the outermost guard ring 92. The other structures are similar to those of the semiconductor device 100 described in Fig. 4. The second high concentration region 202 may be provided from the upper surface 21 of the semiconductor substrate 10 to below the lower end of the channel stopper 174, or may be provided to above the lower end of the channel stopper 174.

[0260] FIG. 34 shows an example of the carrier concentration distribution in the dd line shown in FIG. 4 or FIG. 33. This distribution is similar to the example shown in FIG. 5. In this example, the distance in the depth direction between the bottom end of the second high concentration region 202 and the top end of the first high concentration region 304 is set to D6. The bottom end of the second high concentration region 202 and the top end of the first high concentration region 304 have a carrier concentration of the bulk donor concentration N00 The lower end of the second high concentration region 202 and the upper end of the first high concentration region 304 are positions where the carrier concentration becomes larger than the bulk donor concentration N 00 It may be at a position where the distance is twice as long as the distance .

[0261] Distance D6 is preferably 50 μm or less. That is, in edge termination structure 90, the width in the Z-axis direction of the region sandwiched between first high concentration region 304 and second high concentration region 202 is preferably 50 μm or less. If distance D6 is too large, it becomes difficult to suppress the extension of the depletion layer in edge termination structure 90. As a result, the depletion layer may reach the side surface of semiconductor substrate 10, increasing leakage current. Distance D6 may be 40 μm or less, or may be 30 μm or less. Distance D6 may be 15 μm or more. If distance D6 is too small, edge termination structure 90 may not have sufficient breakdown voltage. Distance D6 may be 17 μm or more.

[0262] The distance in the Z-axis direction between the lower end of the second high concentration region 202 and the upper surface 21 of the semiconductor substrate 10 is defined as D7. Distance D7 may be 2 μm or more. Distance D7 may be 3 μm or more, or may be 5 μm or more. Distance D7 may be smaller than the length of the guard ring in the depth direction.

[0263] FIG. 35 shows the dose ( / cm 2 ) of the N-type dopant in the second high concentration region 202 shown in FIG. 2 35 is a diagram showing the relationship between the amount of surface charge (V) of the semiconductor device 100 and the breakdown voltage (V) of the semiconductor device 100. The N-type dopant in this example is phosphorus. The rated value of the breakdown voltage of the semiconductor device 100 is Vr. The rated voltage Vr is a voltage between 1000V and 1500V. The breakdown voltage of the semiconductor device 100 is the emitter-collector voltage at which avalanche breakdown occurs. In the example of FIG. 35, the amount of surface charge on the upper surface of the interlayer insulating film 38 is in the range of 0, -2×10 12 / cm 2 , +2×10 12 / cm 2 The relationship shown in Fig. 35 was measured at room temperature (25°C). In this example, the distance D7 is about 3 µm, and the distance D6 is about 17 µm.

[0264] In this example, regardless of the amount of surface charge, the dose of the second high concentration region 202 is 5×10 11 / cm 2 If the dose is 5×10 or less, the breakdown voltage of the semiconductor device 100 is hardly decreased and can be maintained at or above the rated value. 11 / cm 2 When the dose of the second high concentration region 202 exceeds 5×10, the rated voltage is small when the surface charge amount is negative. 11 / cm 2 It is preferable that:

[0265] FIG. 36 shows the dose of N-type dopant ( / cm 2 35A and 35B are diagrams showing another example of the relationship between the thickness of the semiconductor device 100 and the breakdown voltage (V) of the semiconductor device 100. In the semiconductor device 100 of this example, the length in the X-axis direction of the edge termination structure 90 (edge ​​length) is smaller than in the example shown in FIG. The other conditions are the same as in the example of FIG.

[0266] In this example, the dose of the second high concentration region 202 is 1×10 11 / cm 2 When the dose of the second high concentration region 202 is smaller than 1×10, the breakdown voltage in the example where a negative surface charge is applied is decreased. 11 / cm 2 35, the dose of the second high concentration region 202 is preferably 5×10 11 / cm 2 When the dose of the second high concentration region 202 exceeds 5×10, the rated voltage is small when the surface charge amount is negative. 11 / cm 2 It is preferable that the dose of the second high concentration region 202 is equal to or less than the above range. Note that the dose of the second high concentration region 202 may be an integral value obtained by integrating the donor concentration distribution of the second high concentration region 202 from the upper surface 21 over a distance D7.

[0267] Fig. 37 is a flow chart showing an example of a manufacturing process of the semiconductor device 100. Each process shown in Fig. 37 may be performed on a semiconductor substrate 10 in a wafer state. A plurality of semiconductor substrates 10 can be cut out from the wafer. Bulk donors such as phosphorus are distributed throughout the wafer.

[0268] First, in the upper surface side structure formation step S502, each structure to be provided on the upper surface 21 side of the semiconductor substrate 10 is formed. The structure on the upper surface 21 side includes at least one of the emitter region 12, the base region 14, the accumulation region 16, the well region 11, the second high concentration region 202, each trench portion, the interlayer insulating film 38, the emitter electrode 52, the gate wiring, the guard ring 92, the field plate 94, and the channel stopper 174.

[0269] Next, in a grinding step S504, the lower surface 23 side of the semiconductor substrate 10 is ground to adjust the thickness of the semiconductor substrate 10 in the Z-axis direction. In S504, the thickness of the semiconductor substrate 10 in the Z-axis direction is determined according to the withstand voltage that the semiconductor device 100 should have. In S504, the semiconductor substrate 10 may be ground by a method such as back grinding or CMP.

[0270] Next, in measurement step S506, the thickness of the semiconductor substrate 10 is measured. In S506, probes may be brought into contact with both the upper surface 21 and the lower surface 23 of the semiconductor substrate 10, and the thickness of the semiconductor substrate 10 may be measured from the distance between the probes. Alternatively, infrared rays may be irradiated onto the semiconductor substrate 10, and the thickness of the semiconductor substrate 10 may be measured from the spectrum of interference light between the reflected light from the upper surface 21 side of the semiconductor substrate 10 and the reflected light from the lower surface 23 side. The method of measuring the thickness of the semiconductor substrate 10 is not limited to these.

[0271] Next, in a first hydrogen implantation step S508, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 toward the upper surface 21 of the semiconductor substrate 10. This forms the hydrogen peak portion 302 as described in FIG. 5. In S508, the implantation conditions of the hydrogen ions are adjusted according to the thickness of the semiconductor substrate 10 measured in S506. The implantation conditions of the hydrogen ions may include the implantation depth of the hydrogen ions. The implantation depth of the hydrogen ions is the distance from the lower surface 23 of the semiconductor substrate 10 to the apex of the hydrogen peak portion 302.

[0272] When hydrogen ions are implanted at a constant implantation depth, if the thickness of the semiconductor substrate 10 varies, the distance between the hydrogen peak portion 302 and the upper surface 21 of the semiconductor substrate 10 varies. This distance corresponds to the distance between the upper end of the first high concentration region 304 and the upper surface 21 of the semiconductor substrate 10. The area between the upper end of the first high concentration region 304 and the upper surface 21 of the semiconductor substrate 10 is the bulk doping region 18, and this distance is the thickness of the bulk doping region 18 in the depth direction. If this distance varies, it will affect the way the depletion layer spreads in the edge termination structure 90. Therefore, if this distance varies, the characteristics of the semiconductor device 100 will vary.

[0273] In S508, the implantation depth of the hydrogen ions may be adjusted according to the thickness of the semiconductor substrate 10 so that the distance between the hydrogen peak portion 302 and the upper surface 21 of the semiconductor substrate 10, i.e., the thickness of the bulk doping region 18, becomes a predetermined value. The implantation depth of the hydrogen ions can be adjusted by, for example, the acceleration energy of the hydrogen ions.

[0274] A target thickness of the semiconductor substrate 10 is D (μm), and a distance between the upper end of the first high concentration region 304 and the upper surface 21 of the semiconductor substrate 10 is Z (μm). The distance X from the upper end of the first high concentration region 304 to the lower surface 23 of the semiconductor substrate 10 (i.e., the range Rp of the hydrogen ions) is X=DZ. When the thickness of the semiconductor substrate 10 matches the target value D, the acceleration energy E (eV) of the hydrogen ions to be set in the first hydrogen implantation stage S508 is given by the formula (1), where y=log(E) and x=log(X). y=-0.0047x 4 +0.0528x 3 -0.2211x 2 +0.9923x+5.0474...Formula (1)

[0275] The difference between the measured thickness A of the semiconductor substrate 10 measured in S506 and the target thickness D is defined as d=DA. If the difference d is greater than 0, this indicates that the semiconductor substrate 10 has been over-grinded in S504 and has become thin. If the difference d is less than 0, this indicates that the semiconductor substrate 10 has not been ground enough and has become thick. Taking the difference d into consideration, the distance X' from the upper end of the first high concentration region 304 to the lower surface 23 of the semiconductor substrate 10 is X'=Xd=DZd.

[0276] When the difference d is taken into consideration, the acceleration energy E (eV) of the hydrogen ions to be set in the first hydrogen implantation stage S508 is given by the formula (2), where y1=log(E') and x1=log(X'). y1=-0.0047x1 4 +0.0528x1 3 -0.2211x1 2 +0.9923x1+5.0474...Formula (2)

[0277] Furthermore, in S508, the implantation depth of the hydrogen ions may be adjusted depending on the characteristics such as the thickness of the shielding member disposed on the lower surface 23 of the semiconductor substrate 10 in S507. Furthermore, both the acceleration energy E of the hydrogen ions and the characteristics of the shielding member may be adjusted. For example, the implantation depth may be roughly adjusted by the thickness of the shielding member, and the implantation depth may be adjusted with higher resolution by the acceleration energy E. A lower shielding member formation step S507 may be included between S506 and S508. The lower shielding member formation step S507 will be described later.

[0278] Next, in annealing step S510, the entire semiconductor substrate 10 is annealed. This allows the first high concentration region 304 to be formed in the passage region through which the hydrogen ions have passed. Since the implantation depth of the hydrogen ions is adjusted in S508, the upper end position in the Z-axis direction of the first high concentration region 304 can be adjusted.

[0279] Next, in lower surface side structure formation step S512, a structure on the lower surface 23 side of the semiconductor substrate 10 is formed. The structure on the lower surface 23 side may include at least one of the buffer region 20, the collector region 22, the cathode region 82, and the collector electrode 24, for example. It is preferable that the lower surface side structure formation step S512 does not include a process of annealing the entire semiconductor substrate 10 at a temperature higher than that of the annealing step S510. When forming the collector region 22 and the cathode region 82, local annealing may be performed by a laser or the like. This makes it possible to reduce the thermal history after the formation of the first high concentration region 304.

[0280] 38A is a diagram showing an example of the first hydrogen implantation step S508. In this example, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 in a state in which a shielding member 351 is formed on the lower surface 23 of the semiconductor substrate 10. The shielding member 351 in this example is, for example, a photosensitive resist material applied to the lower surface 23 of the semiconductor substrate 10.

[0281] In S507, based on the thickness of semiconductor substrate 10 measured in S506, thickness T1 of shielding member 351 to be disposed on lower surface 23 is calculated, and shielding member 351 is formed to adjust the implantation depth of hydrogen ions. If the measured value of the thickness of semiconductor substrate 10 is greater than a predetermined target value, thickness T1 of shielding member 351 is reduced to increase range Rp of the hydrogen ions, and if the measured value is less than the target value, thickness T1 of shielding member 351 is increased to decrease range Rp of the hydrogen ions. The amount of change in range Rp of the hydrogen ions when thickness T1 of shielding member 351 is changed may be measured in advance.

[0282] Furthermore, in S508, the range Rp of the hydrogen ions may be adjusted depending on the degree of hardening of the shielding member 351. The degree of hardening of the shielding member 351 can be adjusted by the exposure time or the like. The amount of change in the range Rp of the hydrogen ions when the hardening of the shielding member 351 is adjusted may be measured in advance.

[0283] FIG. 38B is a diagram showing an example of hydrogen ion implantation through a shielding member 351. The shielding member 351 is formed on the lower surface 23. If there is variation in the thickness of the semiconductor substrate 10 after grinding within the surface of the semiconductor substrate 10, the distance Z between the upper end of the first high concentration region 304 and the upper surface 21 of the semiconductor substrate 10 also varies. Therefore, after forming the shielding member 351 on the lower surface 23, hydrogen ions are implanted into the lower surface 23. When the shielding member is a resist film, the coated surface after the resist film is applied can be flattened regardless of the unevenness of the lower surface 23 of the underlying semiconductor substrate 10. This can reduce the effect of the variation in the thickness of the semiconductor substrate 10 within the surface on the distance Z.

[0284] The measured thickness of the semiconductor substrate 10 in the measurement step S506 after grinding has a maximum value Amax. and a minimum value Amin. in the surface of the substrate. At this time, the average thickness Ac after grinding is defined as Ac=(Amax.+Amin.) / 2. In FIG. 38B, the average surface 25 corresponding to the average value Ac is shown by a broken line. If the measured value A in S506 is Ac and the difference d between the measured value A and the target value D is d=D-Ac, then Ac=Dd. The hydrogen ion implantation in step S508 is performed through a shielding member 351 having a thickness T1 (μm). Therefore, the distance X' from the upper end of the first high concentration region 304 to the lower surface 23 of the semiconductor substrate 10, taking into account the difference d, is X'=Ac+T1-Z, taking into account the thickness T1 of the shielding member 351. Here, the thickness T1 of the shielding member 351 is defined as the thickness from the average surface 25 corresponding to the average measured value Ac to the surface on the opposite side to the average surface 25. Since Ac is Dd, X'=D-d+T1-Z. By substituting X' into equation (2), the acceleration energy E (eV) of the hydrogen ions to be set in the first hydrogen implantation step S508 can be obtained.

[0285] 39 is a diagram showing another example of the first hydrogen implantation step S508. In this example, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 with a shielding member 352 disposed on the lower surface 23 side of the semiconductor substrate 10. The shielding member 352 in this example is a solid member formed of a metal material such as aluminum or other material. The shielding member 352 may be disposed away from the lower surface 23.

[0286] Also in this example, the thickness T2 of the shielding member 352 disposed on the lower surface 23 is adjusted based on the measured thickness of the semiconductor substrate 10. The method of adjusting the thickness T2 may be the same as the method of adjusting the thickness T1 shown in FIG.

[0287] When the acceleration energy E of the hydrogen ions is fixed, the relationship with the range Rp of the hydrogen ions in the first hydrogen implantation step S508 is given by equation (3), where y2=log(Rp) and x2=log(E). y2=-0.0082x2 4 +0.1664x2 3 -1.0210x2 2 +2.8528x2-4.4625...Formula (3) From the formula (3), the range of hydrogen ions that should be reduced by the thickness T2 of the shielding member 352 is T2=Rp-X'=10 y2 -D+Z+d (μm). Between the lower surface 23 and the shielding member 352, the shielding member 351 in contact with the lower surface 23 may be formed in S507. This reduces the effect of the thickness variation of the semiconductor substrate 10. In this case, X'=D-d+T1-Z, and T2=Rp-X'=10 y2 -(D-d+T1-Z) (μm).

[0288] The acceleration energy of the hydrogen ions may be set according to the largest possible variation in thickness of the semiconductor substrate 10. The smaller the thickness of the semiconductor substrate 10, the smaller the thickness of the shielding member may be. This allows the implantation depth of the hydrogen ions to be adjusted without changing the acceleration energy. Also, when the thickness T2 of the shielding member 352 becomes small, it becomes difficult to adjust the thickness T2. For this reason, the acceleration energy of the hydrogen ions may be set so that the thickness T2 of the shielding member 352 is equal to or greater than a predetermined value even if the thickness of the semiconductor substrate 10 varies. The predetermined value is, for example, 100 μm or greater.

[0289] In the first hydrogen implantation step S508, the dose of hydrogen ions may be adjusted based on the thickness of the semiconductor substrate 10. If the thickness of the semiconductor substrate 10 varies, the breakdown voltage of the semiconductor device 100 may vary. In response to this, the dose of hydrogen ions may be adjusted to adjust the breakdown voltage of the semiconductor device 100. For example, if the thickness of the semiconductor substrate 10 is smaller than a predetermined target value, the breakdown voltage may be reduced. In this case, the dose of hydrogen ions may be reduced in S508. The reduction in the breakdown voltage can be suppressed by reducing the concentration of hydrogen donors formed in the hydrogen ion passage region. If the thickness of the semiconductor substrate 10 is larger than a predetermined target value, the dose of hydrogen ions may be increased. The relationship between the thickness of the semiconductor substrate 10 and the preferred dose of hydrogen ions may be measured in advance.

[0290] In addition, in the annealing step S510, the annealing conditions of the semiconductor substrate 10 may be adjusted based on the thickness of the semiconductor substrate 10. The annealing conditions include at least one of the annealing time and the annealing temperature. When the thickness of the semiconductor substrate 10 is greater than a predetermined target value, the annealing time may be adjusted or the annealing temperature may be adjusted so that the concentration of hydrogen donors formed in the hydrogen ion passage region is higher than the target value. When the thickness of the semiconductor substrate 10 is smaller than a predetermined target value, the annealing time may be adjusted or the annealing temperature may be adjusted so that the concentration of hydrogen donors formed in the hydrogen ion passage region is lower than the target value.

[0291] 40 is a flowchart showing another example of the manufacturing process of the semiconductor device 100. In this example, a second hydrogen implantation step S509 is included before the annealing step S510. The second hydrogen implantation step S509 is performed after the measurement step S506. The steps other than the second hydrogen implantation step S509 are the same as those in the example of FIG.

[0292] In the second hydrogen implantation step S509, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 into a region on the lower surface 23 side of the semiconductor substrate 10. In S509, hydrogen ions may be implanted into any peak position of the carrier concentration of the buffer region 20 shown in Fig. 5. In S509, hydrogen ions may be implanted into each peak position of the buffer region 20.

[0293] The hydrogen ions implanted into the lower surface 23 of the semiconductor substrate 10 diffuse toward the upper surface 21 of the semiconductor substrate 10 by the annealing step S510. This makes it easier to form hydrogen donors in the first high concentration region 304. The donor concentration in the first high concentration region 304 can also be adjusted by the dose of hydrogen ions implanted into the lower surface 23 of the semiconductor substrate 10. The donor concentration in the first high concentration region 304 can also be adjusted by the depth position of the hydrogen ions implanted into the lower surface 23 of the semiconductor substrate 10.

[0294] In S509 of this example, the implantation conditions of the hydrogen ions implanted on the lower surface 23 side are adjusted according to the measured thickness of the semiconductor substrate 10. The implantation conditions include at least one of the dose amount and the implantation depth of the hydrogen ions. This allows the donor concentration of the first high concentration region 304 to be adjusted to adjust the breakdown voltage of the semiconductor device 100. For example, when the thickness of the semiconductor substrate 10 is smaller than a predetermined target value, the breakdown voltage may be reduced. In this case, the dose amount of the hydrogen ions may be adjusted in S509 to suppress a decrease in the breakdown voltage. The implantation depth of the hydrogen ions may be adjusted. When the thickness of the semiconductor substrate 10 is larger than a predetermined target value, the dose amount of the hydrogen ions may be adjusted, or the implantation depth of the hydrogen ions may be adjusted. The relationship between the preferred dose amount or implantation depth of the hydrogen ions and the thickness of the semiconductor substrate 10 may be measured in advance.

[0295] In S509, the conditions for implanting hydrogen ions into the highest hydrogen concentration peak among the multiple hydrogen concentration peaks in the buffer region 20 may be adjusted. Also, the conditions for implanting hydrogen ions into the peak closest to the lower surface 23 of the semiconductor substrate 10 among the multiple hydrogen concentration peaks in the buffer region 20 may be adjusted.

[0296] 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 clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0297] For example, in order to adjust the electric field distribution in the active section 160 and the edge termination structure section 90, a structure having a first high concentration region 304, a second high concentration region 202, and a fourth high concentration region 404 as shown in FIG. 41 is also included.

[0298] Fig. 41 is a diagram showing another example of the cc cross section in Fig. 1. The semiconductor device 100 of this example differs from the other configuration examples in this specification in the arrangement of each high concentration region. The other structures are similar to any of the examples described in this specification.

[0299] The semiconductor device 100 of this example has a first high concentration region 304-6, a first high concentration region 304-7, a second high concentration region 202, and a fourth high concentration region 404. The shape of each high concentration region can be an appropriate combination of each high concentration region described in this specification.

[0300] At least a portion of the first high concentration region 304-6 and the first high concentration region 304-7 are provided in the edge termination structure 90. In the example shown in FIG. 41, the first high concentration region 304-6 is similar to the first high concentration region 304 described in FIG. 25A. The first high concentration region 304-7 has a lower doping concentration than the first high concentration region 304-6 and is disposed above the first high concentration region 304-6. The entire first high concentration region 304-6 may be disposed below the first high concentration region 304-7.

[0301] 21. However, the shapes of the first high concentration region 304-6, the first high concentration region 304-7 and the second high concentration region 202 may be the shapes of other high concentration regions described in this specification. As shown in FIG. 41, the second high concentration region 202 may also be provided between the channel stopper 174 and the guard ring 92 closest to the channel stopper 174. The second high concentration region 202 may be formed by implanting phosphorus or may be formed with a hydrogen donor.

[0302] The fourth high concentration region 404 is formed in the active section 160. The fourth high concentration region 404 may have a lower concentration than the first high concentration region 304-6. The fourth high concentration region 404 may have a lower concentration than the first high concentration region 304-7. The upper end of the first high concentration region 304-7 may be disposed closer to the upper surface 21 than the upper end of the fourth high concentration region 404. In the example of FIG. 41, the upper end of the fourth high concentration region 404 is disposed below each trench portion or well region 11. In the active section 160, an N-type bulk doping region 18 may be provided on the fourth high concentration region 404, and a P-type low concentration region 17 may be provided.

[0303] An upper end of the first high concentration region 304-7 is located above a lower end of the well region 11 or a lower end of the guard ring 92. In another example, an upper end of the fourth high concentration region 404 in the edge termination structure 90 may be located below the well region 11 or the guard ring 92. An upper end of the first high concentration region 304-7 is located below a lower end of the second high concentration region 202. That is, the first high concentration region 304-7 and the second high concentration region 202 are located apart from each other. In this example, a bulk doping region 18 is provided between the first high concentration region 304-7 and the second high concentration region 202 in the edge termination structure 90.

[0304] In the above-mentioned embodiments, the first high concentration region 304 is formed by ion implantation of hydrogen, but the present invention is not limited thereto. For example, the first high concentration region 304 can be formed by implanting helium ions to generate disorder in the substrate, and diffusing hydrogen into the substrate to generate VOH defects. In this case, the hydrogen peak portion 302 contains helium. This also achieves the effect of suppressing the lateral spread of the electric field as shown in FIG. 6. The first high concentration region 304 can also be formed by diffusing and activating other impurity elements that form a donor band from the lower surface 23.

[0305] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0306] 10 semiconductor substrate, 11 well region, 12 emitter region, 14 base region, 15 contact region, 16 accumulation region, 17 low concentration region, 18 bulk doping region, 19 drift region, 20 buffer region, 21 upper surface, 22 collector region, 23 lower surface, 24 collector electrode, 25 average surface, 29 straight line portion, 30 dummy trench portion, 31 tip portion, 32 dummy insulator insulating film, 34 dummy conductive portion, 38 interlayer insulating film, 39 straight portion, 40 gate trench portion, 41 tip 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 termination structure portion, 91 region, 92 guard ring, 93 side surface, 9 4 field plate, 95 gap, 98 opening, 100 semiconductor device, 102 edge, 112 gate pad, 130 peripheral gate wiring, 131 active side gate wiring, 140 protective film, 160 active portion, 174 channel stopper, 202 second high concentration region, 203 third high concentration region, 204 region, 206 upper portion, 208 lower portion, 209 region, 260 lower region, 261 Lower region, 262 Equipotential surface, 302 Hydrogen peak portion, 304 First high concentration region, 306, 308, 310 Equipotential surface, 312, 314 Peak, 313, 317 Plateau, 318 First peak, 320, 322, 324, 326 Slope, 323, 327 Plateau, 330, 332, 334, 336, 338 Point, 350, 351, 352 Shielding member, 404 Fourth high concentration region, 502 Fifth high concentration region

Claims

1. a semiconductor substrate having a bulk doped region of a first conductivity type having a bulk donor distributed therethrough and a doping concentration of said bulk donor; an active portion provided on the semiconductor substrate; an edge termination structure provided on the semiconductor substrate, the edge termination structure being provided on a top surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate; Equipped with the edge termination structure includes a first highly doped region of a first conductivity type in a region between a top surface and a bottom surface of the semiconductor substrate, the first highly doped region having a donor concentration greater than a doping concentration of the bulk donors; an upper surface of the first high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the first high concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region is disposed on an upper surface side of the semiconductor substrate and has a hydrogen peak portion where a hydrogen concentration shows a peak in a hydrogen concentration distribution in a depth direction; in at least a portion of the edge termination structure including a portion in contact with the active portion, a donor concentration from a depth position of the hydrogen peak portion to a bottom surface of the semiconductor substrate is higher than a doping concentration of the bulk donor; a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, the second high concentration region having a doping concentration higher than that of the bulk doped region; a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure, the guard ring having a doping concentration higher than a doping concentration of the bulk donor; a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or the one or more guard rings on the edge side of the semiconductor substrate; Semiconductor device.

2. a semiconductor substrate having a bulk doped region of a first conductivity type having a bulk donor distributed therethrough and a doping concentration of said bulk donor; an active portion provided on the semiconductor substrate; an edge termination structure provided on the semiconductor substrate, the edge termination structure being provided on a top surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate; Equipped with the edge termination structure includes a first highly doped region of a first conductivity type in a region between a top surface and a bottom surface of the semiconductor substrate, the first highly doped region having a donor concentration greater than a doping concentration of the bulk donors; an upper surface of the first high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the first high concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region has a flat portion in which the carrier concentration is uniform in a depth direction, a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, the second high concentration region having a doping concentration higher than that of the bulk doped region; a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure, the guard ring having a doping concentration higher than a doping concentration of the bulk donor; a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or the one or more guard rings on the edge side of the semiconductor substrate; Semiconductor device.

3. a semiconductor substrate having a bulk doped region of a first conductivity type having a bulk donor distributed therethrough and a doping concentration of said bulk donor; an active portion provided on the semiconductor substrate; an edge termination structure provided on the semiconductor substrate, the edge termination structure being provided on a top surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate; Equipped with the edge termination structure includes a first highly doped region of a first conductivity type in a region between a top surface and a bottom surface of the semiconductor substrate, the first highly doped region having a donor concentration greater than a doping concentration of the bulk donors; an upper surface of the first high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the first high concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region is disposed on an upper surface side of the semiconductor substrate and has a hydrogen peak portion where a hydrogen concentration shows a peak in a hydrogen concentration distribution in a depth direction; the first high concentration region on the upper surface side of the hydrogen peak portion has a smaller width in the depth direction than the first high concentration region on the lower surface side of the hydrogen peak portion, a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, the second high concentration region having a doping concentration higher than that of the bulk doped region; a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure, the guard ring having a doping concentration higher than a doping concentration of the bulk donor; a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or the one or more guard rings on the edge side of the semiconductor substrate; Semiconductor device.

4. a semiconductor substrate having a bulk doped region of a first conductivity type having a bulk donor distributed therethrough and a doping concentration of said bulk donor; an active portion provided on the semiconductor substrate; an edge termination structure provided on the semiconductor substrate, the edge termination structure being provided on a top surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate; Equipped with the edge termination structure includes a first highly doped region of a first conductivity type in a region between a top surface and a bottom surface of the semiconductor substrate, the first highly doped region having a donor concentration greater than a doping concentration of the bulk donors; an upper surface of the first high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the first high concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region is disposed on an upper surface side of the semiconductor substrate and has a hydrogen peak portion where a hydrogen concentration shows a peak in a hydrogen concentration distribution in a depth direction; a slope of the hydrogen concentration distribution on the upper surface side of the hydrogen peak portion is greater than a slope of the hydrogen concentration distribution on the lower surface side of the hydrogen peak portion; a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, the second high concentration region having a doping concentration higher than that of the bulk doped region; a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure, the guard ring having a doping concentration higher than a doping concentration of the bulk donor; a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or the one or more guard rings on the edge side of the semiconductor substrate; Semiconductor device.

5. a semiconductor substrate having a bulk doped region of a first conductivity type having a bulk donor distributed therethrough and a doping concentration of said bulk donor; an active portion provided on the semiconductor substrate; an edge termination structure provided on the semiconductor substrate, the edge termination structure being provided on a top surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate; Equipped with the edge termination structure includes a first highly doped region of a first conductivity type in a region between a top surface and a bottom surface of the semiconductor substrate, the first highly doped region having a donor concentration greater than a doping concentration of the bulk donors; an upper surface of the first high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the first high concentration region is located on the lower surface side of the semiconductor substrate, the first high concentration region has a depth direction length that gradually increases as it is away from the active portion, a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, the second high concentration region having a doping concentration higher than that of the bulk doped region; a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure, the guard ring having a doping concentration higher than a doping concentration of the bulk donor; a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or the one or more guard rings on the edge side of the semiconductor substrate; Semiconductor device.

6. a semiconductor substrate having bulk donors of a first conductivity type distributed throughout; an active portion provided on the semiconductor substrate; an edge termination structure provided on the semiconductor substrate, the edge termination structure being provided on a top surface of the semiconductor substrate between the active portion and an edge of the semiconductor substrate; Equipped with the edge termination structure includes a first highly doped region of a first conductivity type in a region between a top surface and a bottom surface of the semiconductor substrate, the first highly doped region having a donor concentration greater than a doping concentration of the bulk donors; an upper surface of the first high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the first high concentration region is located on the lower surface side of the semiconductor substrate, the active portion has a fourth high concentration region of the first conductivity type in a region between the upper surface and the lower surface of the semiconductor substrate, the fourth high concentration region having a donor concentration higher than a doping concentration of the bulk donor and in contact with at least the first high concentration region; an upper surface of the fourth high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the fourth high concentration region is located on the lower surface side of the semiconductor substrate, An upper end position of the fourth high concentration region is located on the lower surface side of an upper end position of the first high concentration region. Semiconductor device.

7. the semiconductor substrate having a bulk doped region of a first conductivity type having a doping concentration of the bulk donor; a second high concentration region of a first conductivity type on an upper surface side of the semiconductor substrate of the bulk doped region of the edge termination structure, the second high concentration region having a doping concentration higher than that of the bulk doped region; a guard ring of a second conductivity type on an upper surface side of the semiconductor substrate of the edge termination structure, the guard ring having a doping concentration higher than a doping concentration of the bulk donor; a well region of a second conductivity type between the edge termination structure and the active portion, the second high concentration region being adjacent to the well region or the one or more guard rings on the edge side of the semiconductor substrate; The semiconductor device according to claim 6.

8. The first high concentration region is disposed on the upper surface side of the semiconductor substrate and has a hydrogen peak portion where the hydrogen concentration shows a peak in a hydrogen concentration distribution in a depth direction. The semiconductor device according to claim 2 or 5 to 7.

9. The hydrogen peak contains helium The semiconductor device according to claim 8.

10. The edge termination structure includes a plurality of the guard rings.

5. The semiconductor device according to claim 1, 3 or 4.

11. The second high concentration region is provided between two adjacent guard rings. The semiconductor device according to claim 10.

12. The hydrogen peak portion is disposed below the second high concentration region. The semiconductor device according to claim 11.

13. The hydrogen peak portion is disposed between a lower end of the guard ring and the lower surface of the semiconductor substrate. The semiconductor device according to claim 10 .

14. The first high concentration region is in contact with the guard ring. The semiconductor device according to claim 10 .

15. The active portion is a base region of a second conductivity type disposed on an upper surface side of the semiconductor substrate; a distance in the depth direction between the hydrogen peak portion and the second high concentration region is smaller than a maximum value of a distance between the well region and each point of the guard ring that is closest to the well region; The semiconductor device according to claim 11 or 12.

16. the second high concentration region includes hydrogen implanted from the top surface of the semiconductor substrate; the hydrogen peak portion includes hydrogen implanted from the lower surface of the semiconductor substrate, a hydrogen concentration distribution in a depth direction of the second high concentration region has a first peak indicating a peak of hydrogen concentration; The first peak and the hydrogen peak portion overlap.

5. The semiconductor device according to claim 1, 3 or 4.

17. the second high concentration region includes hydrogen implanted from the top surface of the semiconductor substrate; the hydrogen peak portion includes hydrogen implanted from the lower surface of the semiconductor substrate, a hydrogen concentration distribution in a depth direction of the second high concentration region has a first peak indicating a peak of hydrogen concentration; The hydrogen peak portion is disposed between the first peak and the upper surface of the semiconductor substrate.

5. The semiconductor device according to claim 1, 3 or 4.

18. The second high concentration region includes a hydrogen donor. The semiconductor device according to claim 1 , wherein the first insulating layer is a first insulating layer.

19. The second high concentration region is provided between two adjacent guard rings from a position shallower than the lower ends of the guard rings to a position deeper than the lower ends of the guard rings.

19. The semiconductor device according to claim 1, wherein the first and second electrodes are electrically connected to the first and second electrodes.

20. The second high concentration region is in contact with the upper surface of the semiconductor substrate.

20. The semiconductor device according to claim 19.

21. The first high concentration region has a hydrogen donor. The semiconductor device according to claim 1 .

22. The bulk donor is phosphorus or antimony. The semiconductor device according to claim 1 .

23. The first high concentration region is provided in a range not reaching the active portion. The semiconductor device according to claim 1 .

24. The first high concentration region is The inner part and an outer portion that is provided outside the inner portion and has a length in a depth direction of the semiconductor substrate that is greater than that of the inner portion; The semiconductor device according to claim 1 , further comprising:

25. The semiconductor substrate has a bulk acceptor of a second conductivity type distributed throughout.

25. The semiconductor device according to claim 1.

26. The bulk acceptor is boron. The semiconductor device according to claim 25.

27. The dose of the donor in the second high concentration region is 5×10 １１ / cm ２ is less than or equal to The semiconductor device according to claim 1 , wherein the first insulating layer is a first insulating layer.

28. The dose of the donor in the second high concentration region is 1×10 １１ / cm ２ That's all.

28. The semiconductor device according to claim 27.

29. The peak value of the donor concentration in the second high concentration region is 10 times or more the minimum value of the donor concentration in the first high concentration region.

29. The semiconductor device according to claim 1 , wherein the first and second electrodes are electrically connected to the first and second electrodes.

30. The distance between the lower end of the second high concentration region and the upper end of the first high concentration region is 50 μm or less.

30. The semiconductor device according to claim 27.

31. The distance between the lower end of the second high concentration region and the upper end of the first high concentration region is 15 μm or more.

31. The semiconductor device according to claim 27.

32. The depth position of the lower end of the second high concentration region is 2 μm or more away from the upper surface of the semiconductor substrate.

32. The semiconductor device according to claim 27.

33. the active portion has a fourth high concentration region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the fourth high concentration region having a donor concentration higher than a doping concentration of the bulk donor; an upper surface of the fourth high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the fourth high concentration region is located on the lower surface side of the semiconductor substrate, The donor concentration of the fourth high concentration region is different from the donor concentration of the first high concentration region. The semiconductor device according to claim 1 .

34. the active portion has a fourth high concentration region of the first conductivity type in a region between an upper surface and a lower surface of the semiconductor substrate, the fourth high concentration region having a donor concentration higher than a doping concentration of the bulk donor; an upper surface of the fourth high concentration region is located on the upper surface side of the semiconductor substrate; a lower surface of the fourth high concentration region is located on the lower surface side of the semiconductor substrate, The fourth high concentration region has an upper end position different from an upper end position of the first high concentration region. The semiconductor device according to claim 1 .

35. In the edge termination structure, the first high concentration region and the second high concentration region are provided continuously. The semiconductor device according to claim 1 .

36. The second high concentration region is provided between two adjacent guard rings.

8. The semiconductor device according to claim 2, 5 or 7.

37. the edge termination structure includes a plurality of the guard rings; At least a part of the region including a portion in contact with the active portion includes a portion below the guard ring disposed closest to the active portion. The semiconductor device according to claim 1 .

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