Semiconductor device

Abstract

Provided is a semiconductor device including a semiconductor substrate that has a top surface and a bottom surface, in which a bulk donor is distributed between the top surface and the bottom surface, and that is provided with a first conductivity-type drift region, wherein: the semiconductor device includes a first conductivity-type high concentration region that is disposed between the drift region and the bottom surface of the semiconductor substrate, that contains a hydrogen donor, and in which the carrier concentration is higher than the bulk donor concentration; the high concentration region has a first section in which the hydrogen donor concentration in which the bulk donor concentration is subtracted from the carrier concentration is 7×1013 / cm3 to 1.5×1014 / cm3; and, in the depth direction of the semiconductor substrate, the length of the first section is equal to or greater than 50% of the length of the high concentration region.

Description

Semiconductor Devices

[0001] The present invention relates to a semiconductor device.

[0002] Semiconductor devices are known in which hydrogen ions such as protons are implanted into a semiconductor substrate to form hydrogen donors, thereby forming donor regions with a higher concentration than the bulk donor concentration (see, for example, Patent Documents 1 to 3). Problem to be solved

[0003] The characteristics of each element may vary depending on the configuration of the semiconductor device (for example, layer configuration, impurity concentration, etc.) and the manufacturing process. General disclosure

[0004] In order to solve the above-mentioned problems, a first aspect of the present invention provides a semiconductor device including a semiconductor substrate having an upper surface and a lower surface, bulk donors distributed between the upper surface and the lower surface, and a drift region of a first conductivity type. The semiconductor device may further include a high concentration region of the first conductivity type disposed between the drift region and the lower surface of the semiconductor substrate, the high concentration region containing hydrogen donors and having a carrier concentration higher than a bulk donor concentration. In any of the above-mentioned semiconductor devices, the high concentration region has a hydrogen donor concentration, calculated by subtracting the bulk donor concentration from the carrier concentration, of 7×10 １３ / cm ３ That's it, 1.5 x 10 １４ / cm ３ In any of the above semiconductor devices, the length of the first portion in the depth direction of the semiconductor substrate may be 50% or more of the length of the high concentration region.

[0005] In any of the above semiconductor devices, the high-concentration region may have a plurality of hydrogen donor concentration peaks in the depth direction. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks may include a shallowest donor concentration peak closest to the bottom surface of the semiconductor substrate and a deepest donor concentration peak closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the high-concentration region may have a second portion that is a region from the shallowest donor concentration peak to the deepest donor concentration peak. In any of the above semiconductor devices, the length of the first portion may be 50% or more of the length of the second portion in the depth direction of the semiconductor substrate.

[0006] In any of the above semiconductor devices, the high concentration region may have a plurality of hydrogen donor concentration peaks in the depth direction. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks may include a deepest donor concentration peak closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the high concentration region may have a hydrogen donor concentration of 7×10 or more in a region from the bottom surface of the semiconductor substrate to the deepest donor concentration peak. １３ / cm ３ In any of the above semiconductor devices, the third portion may have a length in the depth direction of 15 μm or less, the length in the depth direction of the third portion being continuous with the region of less than 15 μm.

[0007] In any of the above semiconductor devices, the high concentration region may have a plurality of hydrogen donor concentration peaks in the depth direction. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks may include a deepest donor concentration peak closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the high concentration region may have a hydrogen donor concentration of 7×10 or more in a region from the bottom surface of the semiconductor substrate to the deepest donor concentration peak. １３ / cm ３ In any of the above semiconductor devices, the length of the third portion may be 20% or less of the length of the high concentration region in the depth direction of the semiconductor substrate.

[0008] In any of the above semiconductor devices, the high-concentration region may have a plurality of hydrogen donor concentration peaks in the depth direction. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks may include a shallowest donor concentration peak closest to the bottom surface of the semiconductor substrate and a deepest donor concentration peak closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the minimum value of the hydrogen donor concentration from the shallowest donor concentration peak to the deepest donor concentration peak in the high-concentration region is 7×10 １３ / cm ３ It may be more than that.

[0009] In any of the semiconductor devices described above, the high-concentration region may have a plurality of hydrogen chemical concentration peaks in the depth direction, and the length in the depth direction of each hydrogen chemical concentration peak at a portion where the hydrogen chemical concentration is 10% or more of the maximum value may be defined as a hydrogen peak width, and in any of the semiconductor devices described above, the sum of the hydrogen peak widths of the plurality of hydrogen chemical concentration peaks may be 30% or more of the length in the depth direction of the high-concentration region.

[0010] In any of the above semiconductor devices, the sum of the hydrogen peak widths may be 50% or more of the length of the high concentration region.

[0011] In any of the semiconductor devices described above, the plurality of hydrogen chemical concentration peaks may include a same-concentration peak having a concentration that is 0.8 to 1.2 times the concentration of at least one hydrogen chemical concentration peak adjacent to the same-concentration peak in the depth direction. In any of the semiconductor devices described above, three or more of the same-concentration peaks may be arranged consecutively in the depth direction.

[0012] In any of the semiconductor devices described above, the high concentration region may have an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction, and in any of the semiconductor devices described above, three or more of the same concentration peaks may be arranged consecutively in the depth direction in the upper region.

[0013] In any of the above semiconductor devices, the sum of the hydrogen peak widths in the upper region may be 30% or more of the length of the upper region in the depth direction.

[0014] In any of the above semiconductor devices, the hydrogen donors in the high concentration region may include interstitial donors, and the concentration of the interstitial donors may be 30% or more of the concentration of the hydrogen donors.

[0015] In any of the above semiconductor devices, the high-concentration region may have, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks may include a deepest donor concentration peak closest to the top surface of the semiconductor substrate and a second deep donor concentration peak second closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the one or more hydrogen donor concentration valleys may include a deepest donor concentration valley closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, a value obtained by dividing the hydrogen donor concentration at the second deep donor concentration peak by the hydrogen donor concentration at the deepest donor concentration valley may be 1.1 or more and 2.0 or less.

[0016] In any of the above semiconductor devices, the high-concentration region may have a plurality of hydrogen chemical concentration peaks in the depth direction. In any of the above semiconductor devices, the plurality of hydrogen chemical concentration peaks may include a third hydrogen concentration peak that is third closest to the bottom surface of the semiconductor substrate. In any of the above semiconductor devices, the high-concentration region may have a lower region from the bottom surface of the semiconductor substrate to the third hydrogen concentration peak, and an upper region closer to the top surface of the semiconductor substrate than the third hydrogen concentration peak. In any of the above semiconductor devices, the lower region may have a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks in the depth direction. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks in the lower region may include a lower deepest donor concentration peak that is farthest from the bottom surface of the semiconductor substrate. In any of the above semiconductor devices, the one or more hydrogen donor concentration valleys in the lower region may include a lower deepest donor concentration valley that is farthest from the bottom surface of the semiconductor substrate. In any of the above semiconductor devices, the hydrogen donor concentration N １ the hydrogen donor concentration N ２ The value a obtained by dividing by may be 1.2 or more and 4.0 or less.

[0017] In any of the above semiconductor devices, the upper region may have, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks. In any of the above semiconductor devices, the plurality of hydrogen donor concentration peaks in the upper region may include a deepest donor concentration peak closest to the top surface of the semiconductor substrate and a second deep donor concentration peak second closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the one or more hydrogen donor concentration valleys in the upper region may include a deepest donor concentration valley closest to the top surface of the semiconductor substrate. In any of the above semiconductor devices, the hydrogen donor concentration n at the second deep donor concentration peak may be １ n of the hydrogen donor concentration at the deepest donor concentration valley ２The value a / b obtained by dividing the value a by the value b divided by may be greater than 0.5.

[0018] In any one of the above semiconductor devices, the hydrogen donor concentration n １ is the hydrogen donor concentration N at the bottom deepest donor concentration peak １ It may be 0.5 times or less.

[0019] In any of the above semiconductor devices, the high-concentration region may have a lower region closer to the lower surface of the semiconductor substrate than a center of the high-concentration region in the depth direction, and an upper region closer to the upper surface of the semiconductor substrate than the center of the high-concentration region. In any of the above semiconductor devices, the lower region and the upper region may each have, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks. In any of the above semiconductor devices, the hydrogen donor concentration in at least one hydrogen donor concentration valley in the upper region may be higher than the hydrogen donor concentration in at least one hydrogen donor concentration valley in the lower region.

[0020] In any of the semiconductor devices described above, the high concentration region may have an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction. In any of the semiconductor devices described above, the upper region may have a plurality of hydrogen chemical concentration peaks in the depth direction. In any of the semiconductor devices described above, of the plurality of hydrogen chemical concentration peaks in the upper region, 5×10 １５ / cm ３ The sum of the full widths at half maximum of one or more hydrogen chemical concentration peaks having the hydrogen chemical concentration above may be 20% or more and 90% or less of the length of the upper region in the depth direction.

[0021] In any of the semiconductor devices described above, the high concentration region may have an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction. In any of the semiconductor devices described above, the upper region may have a plurality of hydrogen donor concentration peaks in the depth direction. In any of the semiconductor devices described above, among the plurality of hydrogen donor concentration peaks in the upper region, 7×10 １３ / cm ３ The sum of the full widths at half maximum of one or more hydrogen donor concentration peaks having the above hydrogen donor concentrations may be 30% or more of the length of the upper region in the depth direction.

[0022] In any of the semiconductor devices described above, the high concentration region may have an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction. In any of the semiconductor devices described above, an integrated concentration obtained by integrating the hydrogen donor concentration in the depth direction in the upper region is 8×10 １０ / cm ２ That's it, 2 x 10 １１ / cm ２ It may be the following:

[0023] In any of the above semiconductor devices, the high concentration region may have an upper region provided in at least a portion of a range in which the distance in the depth direction from the lower surface of the semiconductor substrate is 25% or more and 50% or less of the thickness of the semiconductor substrate. In any of the above semiconductor devices, the upper region may have a plurality of hydrogen chemical concentration peaks in the depth direction. In any of the above semiconductor devices, among the plurality of hydrogen chemical concentration peaks in the upper region, 5×10 １５ / cm ３ The sum of the full widths at half maximum of one or more hydrogen chemical concentration peaks having the hydrogen chemical concentration above may be 20% or more and 90% or less of the length of the upper region in the depth direction.

[0024] In any of the above semiconductor devices, the high concentration region may have an upper region provided in at least a portion of a range in which the distance in the depth direction from the lower surface of the semiconductor substrate is 25% or more and 50% or less of the thickness of the semiconductor substrate. In any of the above semiconductor devices, the upper region may have a plurality of hydrogen donor concentration peaks in the depth direction. In any of the above semiconductor devices, among the plurality of hydrogen donor concentration peaks in the upper region, 7×10 １３ / cm ３ The sum of the full widths at half maximum of one or more hydrogen donor concentration peaks having the above hydrogen donor concentrations may be 30% or more of the length of the upper region in the depth direction.

[0025] In any of the above semiconductor devices, the high concentration region may have an upper region provided in at least a portion of a range in which the distance from the lower surface of the semiconductor substrate in the depth direction is 25% or more and 50% or less of the thickness of the semiconductor substrate. １０ / cm ２ That's it, 2 x 10 １１ / cm ２ It may be the following:

[0026] In any of the above semiconductor devices, the upper region may be provided over an entire range of 25% to 50% of the thickness of the semiconductor substrate.

[0027] In any one of the above semiconductor devices, the carbon concentration of the semiconductor substrate is 1×10 １３ / cm ３ That's it, 5 x 10 １５ / cm3 or less.

[0028] A second aspect of the present invention provides a semiconductor device including a semiconductor substrate having an upper surface and a lower surface, bulk donors distributed between the upper surface and the lower surface, and a first conductivity type drift region. The semiconductor device may further include a first conductivity type high concentration region disposed between the drift region and the lower surface of the semiconductor substrate, the high concentration region including hydrogen donors and having a carrier concentration higher than a bulk donor concentration. In any of the above semiconductor devices, the high concentration region may have multiple hydrogen chemical concentration peaks in the depth direction. For each hydrogen chemical concentration peak, the depth direction length of a portion where the hydrogen chemical concentration is 10% or more of the maximum value may be defined as a hydrogen peak width, and in any of the above semiconductor devices, the sum of the hydrogen peak widths of the multiple hydrogen chemical concentration peaks may be 30% or more of the depth direction length of the high concentration region.

[0029] In any of the above semiconductor devices, the sum of the hydrogen peak widths may be 50% or more of the length of the high concentration region.

[0030] In any of the semiconductor devices described above, the plurality of hydrogen chemical concentration peaks may include a same-concentration peak having a concentration that is 0.8 to 1.2 times the concentration of at least one hydrogen chemical concentration peak adjacent to the same-concentration peak in the depth direction. In any of the semiconductor devices described above, three or more of the same-concentration peaks may be arranged consecutively in the depth direction.

[0031] In any of the semiconductor devices described above, the high concentration region may have an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction, and in any of the semiconductor devices described above, three or more of the same concentration peaks may be arranged consecutively in the depth direction in the upper region.

[0032] In any of the above semiconductor devices, the sum of the hydrogen peak widths in the upper region may be 30% or more of the length of the upper region in the depth direction.

[0033] In any of the above semiconductor devices, a primary dopant in the drift region may be antimony. In any of the above semiconductor devices, a ratio of a standard deviation of the antimony chemical concentration in a first depth range in a depth direction of the semiconductor substrate to an average concentration of the antimony chemical concentration in the first depth range may be 0.2 or less. In any of the above semiconductor devices, a thickness in the first depth range may be 80% or more and 100% or less of a thickness of the semiconductor substrate.

[0034] A second aspect of the present invention provides a semiconductor device. The semiconductor device may include a semiconductor substrate having an upper surface and a lower surface, and having a first conductivity type drift region provided therein. In any of the above semiconductor devices, a primary dopant in the drift region may be antimony. In any of the above semiconductor devices, a ratio of a standard deviation of antimony chemical concentration in a first depth range in a depth direction of the semiconductor substrate to an average concentration of antimony chemical concentration in the first depth range may be 0.2 or less. In any of the above semiconductor devices, a thickness in the first depth range may be 80% or more and 100% or less of a thickness of the semiconductor substrate.

[0035] In any of the semiconductor devices described above, a ratio of a standard deviation of the antimony chemical concentration in a second depth range in the depth direction of the drift region to an average concentration of the antimony chemical concentration in the second depth range in the depth direction of the drift region may be 0.2 or less. In any of the semiconductor devices described above, a thickness of the second depth range may be 50% or more and 100% or less of a thickness of the drift region.

[0036] In any of the semiconductor devices described above, a high-concentration region having a doping concentration higher than that of the drift region may be provided on the lower surface side of the drift region. In any of the semiconductor devices described above, a ratio of the thickness of the drift region to the sum of the thicknesses of the drift region and the high-concentration region in the depth direction may be 0.1 or more and 0.99 or less.

[0037] A third aspect of the present invention provides a semiconductor device. The semiconductor device may include a semiconductor substrate having an upper surface and a lower surface, and including a first conductivity type drift region. Any of the semiconductor devices may include a high concentration region on the lower surface side of the drift region, the high concentration region having a doping concentration higher than that of the drift region. In any of the semiconductor devices, the drift region may include antimony as a main dopant. In any of the semiconductor devices, the ratio of the thickness of the drift region to the sum of the depthwise thicknesses of the drift region and the high concentration region may be 0.1 or more and 0.99 or less.

[0038] The above summary of the invention does not list all of the necessary features of the present invention. In addition, subcombinations of these features may also constitute inventions.

[0039] 1 is a top view showing an example of a semiconductor device 100 according to an embodiment of the present invention. It is an enlarged view of region D in FIG. 1. It is a diagram showing an example of the e-e cross section in FIG. 2. It is a diagram showing a reference example of the distributions of hydrogen chemical concentration, carrier concentration, and hydrogen donor concentration along line ff in FIG. 3. It is a diagram showing an example of a variation in carrier concentration distribution depending on a variation in oxygen concentration and carbon concentration in a semiconductor substrate 10. It is a diagram showing an example of a variation in hydrogen donor concentration distribution depending on a variation in oxygen concentration and carbon concentration in a semiconductor substrate 10. It is a diagram showing the relationship between the ratio of the hydrogen donor increase amount in each concentration distribution and the hydrogen donor concentration in concentration distribution 310. It is a diagram showing the distributions of hydrogen chemical concentration, carrier concentration, and hydrogen donor concentration along line ff in FIG. 3 according to one embodiment. It is a diagram showing an example of a hydrogen donor concentration distribution in a high concentration region 20. It is a diagram showing another example of a hydrogen donor concentration distribution in a high concentration region 20. It is an enlarged view of hydrogen chemical concentration peak 202-m. It is a diagram showing a hydrogen donor concentration distribution. It is a diagram showing another example of a hydrogen chemical concentration distribution and a hydrogen donor concentration distribution. It is a diagram showing another example of a hydrogen chemical concentration distribution and a hydrogen donor concentration distribution. It is a diagram showing an example of a boundary position Zb. 17A-17C are diagrams showing other examples of the boundary position Zb; FIG. 17B are cross-sectional views taken along the line gg of FIG. 17A showing an example of a doping concentration distribution; FIG. 17C are diagrams showing an example of a chemical concentration distribution of each dopant along the line gg of FIG. 17A showing the distribution of antimony chemical concentration in a second depth range 192 of the drift region 18; FIG. 17C are flowcharts showing a manufacturing method of the semiconductor device 100A; FIG. 17D are diagrams showing steps S1010 to S1030 of the manufacturing method of the semiconductor device 100A; FIG. 17D are diagrams showing steps S1040 to S1060 of the manufacturing method of the semiconductor device 100A; FIG. 17D are diagrams showing steps S1070 to S1090 of the manufacturing method of the semiconductor device 100A; FIG. 17E are diagrams showing characteristics of breakdown voltage variations in the drift region 18 and the high-concentration region 20; and FIG. 17F are graphs showing the relationship between the coefficient ζ and the breakdown voltage variation ratio.

[0040] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0041] 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.

[0042] In this specification, technical matters may be explained using orthogonal coordinate axes of the 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 specifying positive or negative, it means a direction parallel to the +Z-axis and -Z-axis.

[0043] In this specification, orthogonal axes parallel to the upper and lower surfaces of the semiconductor substrate are referred to as the X-axis and Y-axis. Furthermore, an axis perpendicular to the upper and lower surfaces of the semiconductor substrate is referred to as the Z-axis. In this specification, the direction of the Z-axis may be referred to as the depth direction. Furthermore, in this specification, the direction parallel to the upper and lower surfaces of the semiconductor substrate, including the X-axis and Y-axis, may be referred to as the horizontal direction.

[0044] The region from the center of the semiconductor substrate in the depth direction to the top surface of the semiconductor substrate may be referred to as the top surface side. Similarly, the region from the center of the semiconductor substrate in the depth direction to the bottom surface of the semiconductor substrate may be referred to as the bottom surface side.

[0045] In this specification, when we say "same" or "equal," it may also include cases where there is an error due to manufacturing variations, etc. The error is, for example, within 10%.

[0046] In this specification, the conductivity type of a doped region doped with an impurity 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 referred to as a dopant. In this specification, doping means introducing a donor or an acceptor into a semiconductor substrate to form a semiconductor exhibiting an N-type conductivity or a P-type conductivity.

[0047] 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 together the donor concentration as the concentration of positive ions and the acceptor concentration as the concentration of negative ions, taking into account the polarity of the charge. As an example, the donor concentration is N Ｄ , acceptor concentration is N Ａ Then, the net doping concentration at any position is N Ｄ -N Ａ In this specification, the net doping concentration may be simply referred to as the doping concentration.

[0048] 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, a VOH defect in a semiconductor, in which a vacancy (V), oxygen (O), and hydrogen (H) are bonded, functions as a donor that supplies electrons. A hydrogen donor may be a donor in which at least a vacancy (V) and hydrogen (H) are bonded. Alternatively, an interstitial Si—H in a silicon semiconductor, in which interstitial silicon (Si-i) and hydrogen are bonded, also functions as a donor that supplies electrons. Alternatively, a CiOi-H in which interstitial carbon (Ci), interstitial oxygen (Oi), and hydrogen are bonded, also functions as a donor that supplies electrons. In this specification, a VOH defect, an interstitial Si—H, or a CiOi-H may be referred to as a hydrogen donor.

[0049] In this specification, the semiconductor substrate has N-type bulk donors distributed throughout. The bulk donors are donors due to dopants that are uniformly contained in the ingot that is the base of the semiconductor substrate when the ingot is manufactured. In this example, the bulk donors are elements other than hydrogen. The dopants of the bulk donors are, for example, but not limited to, phosphorus, antimony, arsenic, selenium, or sulfur. In this example, the bulk donors are phosphorus. The bulk donors are also contained in the P-type region. The semiconductor substrate 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-applied Czochralski method (MCZ method), and the float zone method (FZ method). The ingot in this example is manufactured by the MCZ method. The oxygen concentration contained in the substrate manufactured by the MCZ method is 1×10 １７ ~7 x 10 １７ / cm ３ The oxygen concentration in the substrate manufactured by the FZ method is 1×10 １５ ~5 x 10 １６ / cm ３ The higher the oxygen concentration, the more likely it is that hydrogen donors are generated. The bulk donor concentration may be the chemical concentration of bulk donors distributed throughout the semiconductor substrate, or may be a value between 90% and 100% of the chemical concentration. Alternatively, a non-doped substrate that does not contain dopants such as phosphorus may be used as the semiconductor substrate. In this case, the bulk donor concentration (D0) of the non-doped substrate is, for example, 1×10 １０ / cm ３ That's it, 5 x 10 １２ / cm ３ The bulk donor concentration (D0) of the non-doped substrate is preferably 1×10 １１ / cm ３ The bulk donor concentration (D0) of the non-doped substrate is preferably 5×10 １２ / cm ３ The concentrations in the present invention may be values ​​at room temperature, for example, values ​​at 300 K (Kelvin) (approximately 26.9° C.).

[0050] In this specification, when P+ type or N+ type is described, it means that the doping concentration is higher than that of P type or N type, and when P- type or N- type is described, it means that the doping concentration is lower than that of P type or N type. Furthermore, when P++ type or N++ type is described in this specification, it means that the doping concentration is higher than that of P+ type or N+ type. The unit system in this specification is the SI unit system unless otherwise specified. The unit of length may be expressed in cm, but various calculations may be performed after converting to meters (m).

[0051] In this specification, chemical concentration refers to the atomic density of an impurity measured regardless of its state of electrical activation. Chemical concentration can be measured, for example, by secondary ion mass spectrometry (SIMS). The net doping concentration can be measured by voltage-capacitance (CV) measurement. The carrier concentration measured by spreading resistance (SR) measurement may be used as the net doping concentration. The carrier concentration measured by CV or SR may be used as the value in a thermal equilibrium state. In addition, since the donor concentration in an N-type region is sufficiently greater than the acceptor concentration, the carrier concentration in that region may be used as the donor concentration. Similarly, in a P-type region, the carrier concentration in that region may be used as the acceptor concentration. In this specification, the doping concentration in an N-type region may be referred to as the donor concentration, and the doping concentration in a P-type region may be referred to as the acceptor concentration. The donor concentration of a hydrogen donor may be 0.1% or more and 50% or less of the hydrogen chemical concentration.

[0052] 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 that 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 that region may be taken as the concentration of the donor, acceptor, or net doping. In this specification, the concentration per unit volume is expressed in atoms / cm. ３ , or / cm ３This unit is used for donor or acceptor concentration or chemical concentration in a semiconductor substrate. The atoms notation may be omitted.

[0053] The carrier concentration measured by the SR method may be lower than the concentration of donors or acceptors. In the range where current flows when measuring 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 carriers are scattered due to disorder in the crystal structure caused by lattice defects or the like.

[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 representing 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 is a substrate made of a semiconductor material. As an example, the semiconductor substrate 10 is a silicon substrate. The semiconductor substrate 10 has end edges 162 in a top view. In this specification, the term "top view" simply refers to a view from the top surface side of the semiconductor substrate 10. The semiconductor substrate 10 in this example has two pairs of end edges 162 that face each other in a top view. In FIG. 1 , the X-axis and Y-axis are parallel to either of the end edges 162. The Z-axis is perpendicular to the top surface of the semiconductor substrate 10.

[0057] An active portion 160 is provided in 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 from FIG. 1 . The active portion 160 may refer to a region overlapped by the emitter electrode in a top view. The active portion 160 may also include a region sandwiched between the active portions 160 in a top view.

[0058] The active section 160 is provided with at least one of a transistor section 70 including a transistor element such as an insulated gate bipolar transistor (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 sections 70 and the diode sections 80 are alternately arranged along a predetermined arrangement direction (in this example, the X-axis direction) on the top surface of the semiconductor substrate 10. The semiconductor device 100 of this example is a reverse conducting IGBT (RC-IGBT).

[0059] In FIG. 1 , the region where the transistor section 70 is arranged is marked with the symbol "I," and the region where 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 (the 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. In other words, the length of the transistor section 70 in the Y-axis direction is greater than the width in the X-axis direction. Similarly, the length of the diode section 80 in the Y-axis direction is greater than the 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, which will be described later.

[0060] The diode section 80 has an N+ type cathode region in a region that contacts 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 that extends the diode section 80 in the Y-axis direction to the gate wiring described below 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. The transistor section 70 also 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 164. The semiconductor device 100 may also have pads such as an anode pad, a cathode pad, and a current detection pad. Each pad is disposed near an edge 162. The vicinity of the edge 162 refers to the region between the edge 162 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 164. The gate pad 164 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 164 and the gate trench portion. In FIG. 1, the gate wiring is hatched with diagonal 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 an edge 162 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 region surrounded by the peripheral gate wiring 130 in a top view may be the active portion 160. In addition, a well region is formed below the gate wiring. The well region is a P-type region with a higher concentration than a base region, which will be described later, and is formed from the top surface of the semiconductor substrate 10 to a position deeper than the base region. The region surrounded by the well region in a top view may be the active portion 160.

[0065] The peripheral gate wiring 130 is connected to the gate pad 164. The peripheral gate wiring 130 is disposed above the semiconductor substrate 10. The peripheral gate wiring 130 may be a metal wiring containing aluminum or the like.

[0066] 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, it is possible to reduce variations in wiring length from the gate pad 164 for each region of the semiconductor substrate 10.

[0067] The peripheral gate wiring 130 and the active side gate wiring 131 are connected to the gate trench portion of the active portion 160. The peripheral gate wiring 130 and the active side gate wiring 131 are disposed above the semiconductor substrate 10. The peripheral gate wiring 130 and the active side gate wiring 131 may be wiring formed of a semiconductor such as polysilicon doped with impurities.

[0068] The active side gate wiring 131 may be connected to the peripheral gate wiring 130. In this example, the active side gate wiring 131 extends in the X axis direction from one peripheral gate wiring 130 to the other peripheral gate wiring 130 that sandwich the active section 160, crossing the active section 160 at approximately the center in the Y axis direction. 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.

[0069] The semiconductor device 100 may include a temperature sensing section (not shown) which is a PN junction diode formed of polysilicon or the like, and a current detecting section (not shown) which simulates the operation of a transistor section provided in the active section 160.

[0070] In the present example, the semiconductor device 100 includes an edge termination structure 90 between the active section 160 and the edge 162 when viewed from above. The edge termination structure 90 in the present example is disposed between the peripheral gate wiring 130 and the edge 162. The edge termination structure 90 relieves electric field concentration on the upper surface side of the semiconductor substrate 10. The edge termination structure 90 may include at least one of a guard ring, a field plate, and a resurf, which are arranged in an annular shape surrounding the active section 160.

[0071] 2 is an enlarged view of region D in FIG. 1 . Region D includes 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 the 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.

[0072] 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 not shown in Fig. 2. In this example, contact holes 54 are provided in the interlayer insulating film so as to penetrate the interlayer insulating film. In Fig. 2, each contact hole 54 is hatched with diagonal lines.

[0073] 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. The dummy conductive portion of the dummy trench portion 30 does not need to be connected to the emitter electrode 52 and the gate conductive portion, and may be controlled to a potential different from the potential of the emitter electrode 52 and the potential of the gate conductive portion.

[0074] 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.

[0075] The emitter electrode 52 is made of a material containing metal. FIG. 2 shows the area where 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 contact hole may have a plug formed by embedding tungsten or the like so as to contact the barrier metal and aluminum or the like.

[0076] 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 into an area where it does not overlap with the active side gate wiring 131. In this example, the well region 11 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.

[0077] 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.

[0078] 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) that extend along an extension direction perpendicular to the arrangement direction, and a tip portion 41 that connects the two straight line portions 39. The extension direction in FIG. 2 is the Y-axis direction.

[0079] At least a portion 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.

[0080] In the transistor section 70, the dummy trench section 30 is provided between each of the linear portions 39 of the gate trench section 40. One or more dummy trench sections 30 may be provided between each of the linear portions 39. The dummy trench section 30 may have a linear shape extending in the extension direction, and may have a linear section 29 and a tip section 31, similar to the gate trench section 40. The semiconductor device 100 shown in FIG. 2 includes both linear dummy trench sections 30 without tip sections 31 and dummy trench sections 30 with tip sections 31.

[0081] The diffusion depth of the well region 11 may be deeper than the depths of the gate trench portion 40 and the dummy trench portion 30. The ends of the gate trench portion 40 and the dummy trench portion 30 in the Y-axis direction are provided in the well region 11 when viewed from above. In other words, at the ends of each trench portion in the Y-axis direction, the bottom of each trench portion in the depth direction is covered by the well region 11. This makes it possible to alleviate electric field concentration at the bottom of each trench portion.

[0082] A mesa portion is provided between each trench portion in the arrangement direction. The mesa portion refers to a region inside the semiconductor substrate 10 that is sandwiched between the trench portions. 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. In this example, the mesa portion 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, the mesa portion simply referred to as a mesa portion refers to both the mesa portion 60 and the mesa portion 61.

[0083] 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 referred to as the base region 14-e. While FIG. 2 shows the base region 14-e located at one end of each mesa portion in the extension direction, a base region 14-e is also located at the other end of each mesa portion. In each mesa portion, at least one of a first-conductivity-type emitter region 12 and a second-conductivity-type contact region 15 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.

[0084] 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.

[0085] The contact regions 15 and the emitter regions 12 in the mesa portion 60 are each provided from one trench portion to the other trench portion in the X-axis direction. As an example, the contact regions 15 and the emitter regions 12 in the mesa portion 60 are alternately arranged along the extension direction of the trench portions (the Y-axis direction).

[0086] 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 of the trench portion (Y-axis direction). 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.

[0087] The mesa portion 61 of the diode section 80 does not have an emitter region 12. A base region 14 and a contact region 15 may be provided on the upper surface of the mesa portion 61. In the 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 the 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.

[0088] A contact hole 54 is provided above each mesa portion. The contact hole 54 is arranged 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 arranged in the center of the arrangement direction (X-axis direction) of the mesa portions 60.

[0089] 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. A P+ type collector region 22 may be provided in a region of the lower surface of the semiconductor substrate 10 where the cathode region 82 is not provided. The cathode region 82 and the collector region 22 are provided between the lower surface 23 of the semiconductor substrate 10 and the high concentration region 20. In FIG. 2 , the boundary between the cathode region 82 and the collector region 22 is indicated by a dotted line.

[0090] 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 deep, 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.

[0091] Fig. 3 is a diagram showing an example of the e-e cross section in Fig. 2. The e-e 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.

[0092] 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 holes 54 described with reference to FIG. 2 .

[0093] 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 contacts 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.

[0094] The semiconductor substrate 10 has an N-type or N-type drift region 18. The drift region 18 is provided in each of the transistor section 70 and the diode section 80.

[0095] 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 drift region 18 is provided below the base region 14. An N+ type accumulation region 16 may be provided in the mesa portion 60. The accumulation region 16 is disposed between the base region 14 and the drift region 18.

[0096] The emitter region 12 is exposed on the upper surface 21 of the semiconductor substrate 10 and is provided in contact with the gate trench portion 40. The emitter region 12 may be in contact with the trench portions on both sides of the mesa portion 60. The emitter region 12 has a higher doping concentration than the drift region 18.

[0097] 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.

[0098] The accumulation region 16 is provided below the base region 14. The accumulation region 16 is an N+ type region with a higher doping concentration than the drift region 18. That is, the accumulation region 16 has a higher donor concentration than the drift region 18. By providing the high-concentration accumulation region 16 between the drift 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.

[0099] A P-type base region 14 is provided in the mesa portion 61 of the diode section 80 in contact with the upper surface 21 of the semiconductor substrate 10. A drift 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.

[0100] In each of the transistor section 70 and the diode section 80, an N+ type high concentration region 20 may be provided below the drift region 18. The doping concentration of the high concentration region 20 is higher than the doping concentration of the drift region 18. The high concentration region 20 may have a concentration peak with a higher doping concentration than the drift region 18. The doping concentration of the concentration peak refers to the doping concentration at the apex of the concentration peak. Furthermore, the doping concentration of the drift region 18 may be the average value of the doping concentration in a region where the doping concentration distribution is approximately flat.

[0101] The high concentration region 20 may have two or more concentration peaks in the depth direction (Z-axis direction) of the semiconductor substrate 10. The concentration peak of the high concentration region 20 may be located at the same depth as the chemical concentration peak of hydrogen (protons) or phosphorus, for example. The high concentration region 20 may function as a field stop layer that prevents the depletion layer extending from the lower end of the base region 14 from reaching the P+ type collector region 22 and the N+ type cathode region 82.

[0102] In the transistor section 70, a P+ type collector region 22 is provided below the high concentration 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.

[0103] In the diode section 80, an N+ type cathode region 82 is provided below the high-concentration region 20. The donor concentration of the cathode region 82 is higher than that of the drift region 18. The donor of the cathode region 82 is, for example, hydrogen or phosphorus. Note that the elements that serve as donors and acceptors in each region are not limited to the above-mentioned examples. The collector region 22 and the cathode region 82 are exposed on the lower surface 23 of the semiconductor substrate 10 and are connected to the collector electrode 24. The collector electrode 24 may be in contact with the entire lower surface 23 of the semiconductor substrate 10. The emitter electrode 52 and the collector electrode 24 are formed of a metal material such as aluminum.

[0104] One or more gate trenches 40 and one or more dummy trenches 30 are provided on the upper surface 21 of the semiconductor substrate 10. Each trench extends from the upper surface 21 of the semiconductor substrate 10, penetrating the base region 14, to below the base region 14. In regions where at least one of the emitter region 12, the contact region 15, and the accumulation region 16 is provided, each trench also penetrates these doped regions. The trenches penetrating the doped regions do not necessarily mean that the trenches are formed in the order of forming the doped regions and then the trenches. The trenches penetrating the doped regions also include trenches formed in the order of forming the trenches and then forming the doped regions.

[0105] As described above, the transistor section 70 is provided with the gate trench section 40 and the dummy trench section 30. The diode section 80 is provided with the dummy trench section 30, but is not provided with the gate trench section 40. In this example, the boundary between the diode section 80 and the transistor section 70 in the X-axis direction is the boundary between the cathode region 82 and the collector region 22.

[0106] 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 trench and further inside than the gate insulating film 42. 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.

[0107] The gate conductive portion 44 may be provided to be 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.

[0108] 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 includes 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 is electrically connected to the emitter electrode 52. The dummy insulating film 32 covers the inner wall of the dummy trench. The dummy conductive portion 34 is provided inside the dummy trench and is provided further inward than the dummy insulating film 32. The dummy insulating film 32 insulates the dummy conductive portion 34 from the semiconductor substrate 10. The dummy conductive portion 34 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 in the depth direction as the gate conductive portion 44.

[0109] 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 have a downwardly convex curved shape (a curved shape in cross section).

[0110] 4 is a diagram showing a reference example of the distribution of the hydrogen chemical concentration, carrier concentration, and hydrogen donor concentration along line ff in FIG. 3. Line ff is a line parallel to the Z axis that passes through the high-concentration region 20. The horizontal axis in FIG. 4 indicates the depth position (position in the Z axis direction) within the semiconductor substrate 10. In this specification, unless otherwise specified, the lower surface 23 of the semiconductor substrate 10 is defined as the reference position in the Z axis direction, and the distance from the lower surface 23 is defined as the position in the Z axis direction.

[0111] The drift region 18 is provided above the high-concentration region 20. The drift region 18 may have a substantially constant doping concentration. The doping concentration of the drift region 18 may be equal to the bulk donor concentration BD. The bulk donor concentration BD is the chemical concentration of bulk donors distributed throughout the semiconductor substrate 10 between the upper surface 21 and the lower surface 23. The bulk donor concentration BD may be the minimum value of the bulk donor chemical concentration in the semiconductor substrate 10, the bulk donor chemical concentration at a central position in the depth direction of the semiconductor substrate 10, or the average value of the bulk donor chemical concentration in the drift region 18. The depth position Z18 of the boundary between the drift region 18 and the high-concentration region 20 is defined as Z18. The depth position Z18 is the depth position where the doping concentration first becomes BD in the direction from the high-concentration region 20 toward the drift region 18.

[0112] A high-concentration region 20 is provided between the drift region 18 and the lower surface 23. A collector region 22 is provided between the high-concentration region 20 and the lower surface 23. The hydrogen chemical concentration, carrier concentration, and hydrogen donor concentration in the collector region 22 are omitted in Fig. 4. A boundary position Z0 between the collector region 22 and the high-concentration region 20 is the position of the PN junction between the collector region 22 and the high-concentration region 20.

[0113] The high concentration region 20 is a region containing hydrogen donors. In this specification, the high concentration region 20 is defined as an N-type region between the drift region 18 and the collector region 22, in which hydrogen atoms exist and the carrier concentration is higher than the bulk donor concentration BD.

[0114] The high-concentration region 20 has a plurality of hydrogen chemical concentration peaks 202 in the depth direction. In the example of FIG. 4 , hydrogen chemical concentration peak 202-1, hydrogen chemical concentration peak 202-2, hydrogen chemical concentration peak 202-3, hydrogen chemical concentration peak 202-4, ..., hydrogen chemical concentration peak 202-k are arranged in the high-concentration region 20 in order from the peak closest to the lower surface 23 of the semiconductor substrate 10. Here, k is an integer of 2 or greater. In this specification, hydrogen chemical concentration peak 202-1 may be referred to as the shallowest hydrogen peak, and hydrogen chemical concentration peak 202-k may be referred to as the deepest hydrogen peak. The maximum value of the hydrogen chemical concentration of hydrogen chemical concentration peak 202-m (m is an integer from 1 to k) is defined as Hpm. In other words, the hydrogen chemical concentration at the apex of hydrogen chemical concentration peak 202-m is defined as Hpm. The depth position Zm of the apex of hydrogen chemical concentration peak 202-m is defined as the depth position of each hydrogen chemical concentration peak 202-m.

[0115] In each example in this specification, the range from the upper end of the collector region 22 to the lower end of the drift region 18 is defined as the high concentration region 20. In each example in this specification, the high concentration region 20 may also be defined as the range from the position Z1 of the apex of the shallowest hydrogen peak (hydrogen chemical concentration peak 202-1) to the position Zk of the apex of the deepest hydrogen peak (hydrogen chemical concentration peak 202-k).

[0116] A hydrogen chemical concentration valley 204 is provided between two adjacent hydrogen chemical concentration peaks 202 in the depth direction. One or more hydrogen chemical concentration valleys 204 are arranged in the high-concentration region 20 in the depth direction. In the example of FIG. 4 , hydrogen chemical concentration valley 204-1, hydrogen chemical concentration valley 204-2, hydrogen chemical concentration valley 204-3, ..., hydrogen chemical concentration valley 204-(k-1) are arranged in the high-concentration region 20, in order from the valley closest to the underside 23 of the semiconductor substrate 10, where k is an integer greater than or equal to 1. In this specification, hydrogen chemical concentration valley 204-1 may be referred to as the shallowest hydrogen valley, and hydrogen chemical concentration valley 204-(k-1) may be referred to as the deepest hydrogen valley. The minimum value of the hydrogen chemical concentration of hydrogen chemical concentration valley 204-m (m is an integer from 1 to k-1) is designated Hvm. That is, the hydrogen chemical concentration at the bottom of the hydrogen chemical concentration valley 204-m is defined as Hvm.

[0117] The high-concentration region 20 has multiple carrier concentration peaks 212 in the depth direction. In the example of FIG. 4 , carrier concentration peak 212-1, carrier concentration peak 212-2, carrier concentration peak 212-3, carrier concentration peak 212-4, ..., carrier concentration peak 212-k are arranged in the high-concentration region 20 in order from the peak closest to the lower surface 23 of the semiconductor substrate 10. Here, k is an integer of 2 or greater. In this specification, carrier concentration peak 212-1 may be referred to as the shallowest carrier peak, and carrier concentration peak 212-k may be referred to as the deepest carrier peak. The maximum value of the carrier concentration of carrier concentration peak 212-m (m is an integer from 1 to k) is defined as Cpm. In other words, the carrier concentration at the apex of carrier concentration peak 212-m is defined as Cpm. Carrier concentration peak 212-m is arranged at the same depth position Zm as hydrogen chemical concentration peak 202-m. If the depth position Zm is included within the full width at half maximum of the carrier concentration peak 212-m in the depth direction, the carrier concentration peak 212-m may be located at the depth position Zm. The apex of the carrier concentration peak 212-m may be located at the depth position Zm.

[0118] A carrier concentration valley 214 is provided between two carrier concentration peaks 212 adjacent to each other in the depth direction. One or more carrier concentration valleys 214 are arranged in the depth direction in the high-concentration region 20. In the example of FIG. 4 , carrier concentration valleys 214-1, 214-2, 214-3, ..., 214-(k-1) are arranged in the high-concentration region 20 in order from the valley closest to the lower surface 23 of the semiconductor substrate 10, where k is an integer greater than or equal to 1. In this specification, carrier concentration valley 214-1 may be referred to as the shallowest carrier concentration valley, and carrier concentration valley 214-(k-1) may be referred to as the deepest carrier concentration valley. The minimum value of the carrier concentration of carrier concentration valley 214-m (m is an integer from 1 to k-1) is defined as Cvm. In other words, the carrier concentration at the bottom of carrier concentration valley 214-m is defined as Cvm.

[0119] At each depth position in the high-concentration region 20, the concentration obtained by subtracting the bulk donor concentration BD from the carrier concentration is defined as the hydrogen donor concentration. The high-concentration region 20 has multiple hydrogen donor concentration peaks 222 in the depth direction. In the example of FIG. 4 , hydrogen donor concentration peak 222-1, hydrogen donor concentration peak 222-2, hydrogen donor concentration peak 222-3, hydrogen donor concentration peak 222-4, ..., hydrogen donor concentration peak 222-k are arranged in the high-concentration region 20, in order from the peak closest to the lower surface 23 of the semiconductor substrate 10, where k is an integer of 2 or greater. In this specification, the hydrogen donor concentration peak 222-1 may be referred to as the shallowest hydrogen donor concentration peak, and the hydrogen donor concentration peak 222-k may be referred to as the deepest hydrogen donor concentration peak. The maximum value of the hydrogen donor concentration peak 222-m (m is an integer from 1 to k) is defined as Dpm. That is, the hydrogen donor concentration at the apex of the hydrogen donor concentration peak 222-m is defined as Dpm. The hydrogen donor concentration peak 222-m is located at the same depth position Zm as the carrier concentration peak 212-m.

[0120] A hydrogen donor concentration valley 224 is provided between two hydrogen donor concentration peaks 222 adjacent to each other in the depth direction. One or more hydrogen donor concentration valleys 224 are arranged in the high-concentration region 20 in the depth direction. In the example of FIG. 4 , hydrogen donor concentration valleys 224-1, 224-2, 224-3, ..., 224-(k-1) are arranged in the high-concentration region 20 in order from the valley closest to the lower surface 23 of the semiconductor substrate 10, where k is an integer of 1 or greater. In this specification, the hydrogen donor concentration valley 224-1 may be referred to as the shallowest hydrogen donor concentration valley, and the hydrogen donor concentration valley 224-(k-1) may be referred to as the deepest hydrogen donor concentration valley. The minimum value of the hydrogen donor concentration of the hydrogen donor concentration valleys 224-m (m is an integer from 1 to k-1) is designated Dvm. That is, the hydrogen donor concentration at the bottom of the hydrogen donor concentration valley 224-m is defined as Dvm.

[0121] Hydrogen donor concentration ( / cm ３ ) is the dose ( / cm ) of hydrogen ions such as protons implanted into the semiconductor substrate 10 ２ ) can be adjusted. For example, increasing the dose of hydrogen ions increases the hydrogen donor concentration. On the other hand, even if the dose of hydrogen ions is constant, the degree to which hydrogen ions become donors varies depending on the oxygen concentration and carbon concentration in the semiconductor substrate 10, resulting in a change in the hydrogen donor concentration. In other words, the donor concentration varies. Therefore, the carrier concentration in the high-concentration region 20 varies depending on the oxygen concentration and carbon concentration in the semiconductor substrate 10. If the carrier concentration in the high-concentration region 20 varies, the characteristics of the semiconductor device 100, such as the breakdown voltage, will vary.

[0122] 5 is a diagram showing an example of the variation in carrier concentration distribution in response to variations in oxygen concentration and carbon concentration in the semiconductor substrate 10. Concentration distribution 300 shows the carrier concentration distribution in the high concentration region 20 when the semiconductor substrate 10, which has sufficiently low oxygen concentration and carbon concentration, is heat-treated by doping hydrogen ions so as to have the hydrogen chemical concentration distribution shown in FIG. 4. The semiconductor substrate 10 in concentration distribution 300 is a substrate formed by, for example, the FZ method, and has an oxygen concentration of 1×10 １６ / cm ３Below, the carbon concentration is 1 × 10 １５ / cm ３ The following is the result.

[0123] The other concentration distributions 302, 304, and 306 show carrier concentration distributions in the high-concentration region 20 when the high-concentration region 20 is formed under the same dose conditions and heat treatment conditions as those for the concentration distribution 300 in a semiconductor substrate 10 having different oxygen and carbon concentrations from those of the concentration distribution 300. The oxygen and carbon concentrations in the semiconductor substrate 10 increase in the order of concentration distribution 300, concentration distribution 302, concentration distribution 304, and concentration distribution 306. The semiconductor substrate 10 in concentration distribution 302 has an oxygen concentration of 3×10 １７ / cm ３ Below, the carbon concentration is 3 × 10 １６ / cm ３ The semiconductor substrate 10 in the concentration distribution 304 has an oxygen concentration of 3×10 １７ / cm ３ ~5 x 10 １７ / cm ３ , carbon concentration is 3×10 １６ / cm ３ ~5 x 10 １６ / cm ３ The semiconductor substrate 10 in the concentration distribution 306 has an oxygen concentration of 5×10 １７ / cm ３ Above, the carbon concentration is 5 × 10 １６ / cm ３ That's all.

[0124] 5, the carrier concentration tends to increase as the oxygen concentration and carbon concentration of the semiconductor substrate 10 increase. Therefore, if the oxygen concentration and carbon concentration of the semiconductor substrate 10 vary, the carrier concentration in the high-concentration region 20 also varies. This is thought to be because the degree of formation of hydrogen donors changes depending on the oxygen concentration and carbon concentration of the semiconductor substrate 10.

[0125] 6 is a diagram showing an example of the variation in hydrogen donor concentration distribution in response to variations in oxygen concentration and carbon concentration in the semiconductor substrate 10. As described above, the hydrogen donor concentration in this specification is the concentration obtained by subtracting the bulk donor concentration B from the carrier concentration. Concentration distributions 310, 312, 314, and 316 correspond to concentration distributions 300, 302, 304, and 306 in FIG. 5.

[0126] The hydrogen donor increase amount is the amount of increase in the hydrogen donor concentration in each concentration distribution when the hydrogen donor concentration in concentration distribution 310 is used as a reference. In Figure 6, the hydrogen donor increase amount in concentration distribution 312 at a certain depth position is illustrated by an arrow, but the hydrogen donor increase amount can be calculated for all depth positions and all concentration distributions. As shown in Figure 6, when the oxygen concentration and carbon concentration in semiconductor substrate 10 vary, the hydrogen donor increase amount also varies.

[0127] 6 , the lower the hydrogen donor concentration in the concentration distribution 310, the greater the variation in the amount of increase in hydrogen donors in other concentration distributions at the same depth. Furthermore, near the peaks of the concentration distribution 310, the variation in the amount of increase in hydrogen donors in each concentration distribution is small, while near the valleys, the variation in the amount of increase in hydrogen donors in each concentration distribution is large. Therefore, by reducing the area of ​​the high-concentration region 20 where the hydrogen donor concentration is low and / or increasing the pulse density in the high-concentration region 20 (the depth ratio of the hydrogen donor peak region to the high-concentration region 20), the variation in the amount of increase in hydrogen donors in the high-concentration region 20 can be suppressed, thereby suppressing the variation in the carrier concentration.

[0128] FIG. 7 is a graph showing the relationship between the hydrogen donor concentration in the concentration distribution 310 and the ratio of the hydrogen donor increase amount in each concentration distribution. The horizontal axis of FIG. 7 represents the hydrogen donor concentration in the concentration distribution 310. The vertical axis of FIG. 7 represents the hydrogen donor increase ratio, which is calculated by dividing the hydrogen donor increase amount (see FIG. 6 ) at each depth position in the concentration distributions 312, 314, and 316 by the hydrogen donor concentration in the concentration distribution 310 at the same depth position. In FIG. 7, the circle plot corresponds to the concentration distribution 316, the cross plot corresponds to the concentration distribution 314, and the triangle plot corresponds to the concentration distribution 312. In this example, the hydrogen donor increase ratio in each concentration distribution at multiple depth positions was calculated for the characteristics shown in FIG. 6. The graph of FIG. 7 was then created by plotting each hydrogen donor increase ratio with the corresponding hydrogen donor concentration in the concentration distribution 310 on the horizontal axis. In FIG. 7, the distributions of the plots corresponding to the concentration distributions 312, 314, and 316 are approximated by straight lines.

[0129] As shown in FIG. 7, the hydrogen donor concentration on the horizontal axis is 7×10 １３ / cm ３ When the hydrogen donor concentration on the horizontal axis is 1×10 or more, the variation in the hydrogen donor increase ratio is almost converged. １４ / cm ３ Above this, the hydrogen donor increase ratio is approximately constant at about 1 to 1.6, regardless of the oxygen concentration and carbon concentration of the semiconductor substrate 10. On the other hand, when the hydrogen donor concentration on the horizontal axis is 7×10 １３ / cm ３ In the region below 7×10, as the hydrogen donor concentration decreases, the hydrogen donor increase ratio in each concentration distribution increases, and the variation between concentration distributions also increases. １３ / cm ３ In the region below 1000 kJ / cm2, the smaller the hydrogen donor concentration is, the greater the variation in the hydrogen donor increase rate due to the oxygen concentration and carbon concentration of the semiconductor substrate 10 is.

[0130] 8 is a diagram showing the distributions of hydrogen chemical concentration, carrier concentration, and hydrogen donor concentration along line ff in FIG. 3 according to one embodiment. In FIG. 8, the same symbols as in the example described in FIG. 4 are used. However, among the multiple hydrogen chemical concentration peaks 202, the m-th peak (m is an integer from 1 to k) counting from the lower surface 23 of the semiconductor substrate 10 is designated as hydrogen chemical concentration peak 202-m. Furthermore, among the multiple hydrogen chemical concentration valleys 204, the m-th valley (m is an integer from 1 to k-1) counting from the lower surface 23 of the semiconductor substrate 10 is designated as hydrogen chemical concentration valley 204-m. The hydrogen chemical concentration at hydrogen chemical concentration peak 202-m is designated as Hpm, and the hydrogen chemical concentration at hydrogen chemical concentration valley 204-m is designated as Hvm.

[0131] 8, of the multiple carrier concentration peaks 212, the m-th peak (m is an integer from 1 to k) counting from the lower surface 23 of the semiconductor substrate 10 is designated as carrier concentration peak 212-m. Also, of the multiple carrier concentration valleys 214, the m-th valley (m is an integer from 1 to k-1) counting from the lower surface 23 of the semiconductor substrate 10 is designated as carrier concentration valley 214-m. The hydrogen chemical concentration of carrier concentration peak 212-m is designated as Cpm, and the carrier concentration of carrier concentration valley 214-m is designated as Cvm.

[0132] 8, of the multiple hydrogen donor concentration peaks 222, the m-th peak (m is an integer from 1 to k) counting from the lower surface 23 of the semiconductor substrate 10 is designated as a hydrogen donor concentration peak 222-m. Also, of the multiple hydrogen donor concentration valleys 224, the m-th valley (m is an integer from 1 to k-1) counting from the lower surface 23 of the semiconductor substrate 10 is designated as a hydrogen donor concentration valley 224-m. The hydrogen donor concentration of the hydrogen donor concentration peak 222-m is designated as Dpm, and the hydrogen donor concentration of the hydrogen donor concentration valley 224-m is designated as Dvm.

[0133] In this example, the high concentration region 20 has a carrier concentration and a hydrogen donor concentration of 7×10 １３ / cm ３4. As a result, even if at least one of the oxygen concentration and the carbon concentration of the semiconductor substrate 10 varies, the variations in the carrier concentration and the hydrogen donor concentration can be suppressed, thereby suppressing the variations in the characteristics of the semiconductor device 100. As an example, the high-concentration region 20 of this example has a higher density of hydrogen chemical concentration peaks 202 in the depth direction than in the example of FIG. 4. As a result, the region where the hydrogen donor concentration is low can be made smaller, and the variations in the carrier concentration and the hydrogen donor concentration can be suppressed.

[0134] 9 is a diagram showing an example of the hydrogen donor concentration distribution in the high concentration region 20. The distribution in FIG. 9 is the same as the hydrogen donor concentration distribution shown in FIG. 8. In the high concentration region 20, the hydrogen donor concentration is 7×10 １３ / cm ３ That's it, 1.5 x 10 １４ / cm ３ The high-concentration region 20 may have a single first portion 231, or may have a plurality of first portions 231 that are discretely arranged in the depth direction. When the apex of the hydrogen donor concentration peak 222-k is included in the first portion 231, the depth position Zk of the hydrogen donor concentration peak 222-k may be the end position of the first portion 231 on the upper surface 21 side.

[0135] In the semiconductor device 100 of this example, the length of the first portion 231 in the depth direction is 50% or more of the length (Z18-Z0) of the high concentration region 20. When a plurality of first portions 231 are provided, the total length of the first portions 231 may be used. By making 50% or more of the high concentration region 20 the first portions 231, the hydrogen donor concentration is 7×10 １３ / cm ３ Therefore, the variation in the carrier concentration and the hydrogen donor concentration can be suppressed. １４ / cm ３By setting the hydrogen donor concentration in the first portion 231 to 1.5×10 or less, it is possible to prevent a peak with an excessively high hydrogen donor concentration from being formed. Therefore, it is possible to suppress the generation of a surge voltage when a space charge region (depletion layer) spreading from the upper surface 21 side of the semiconductor substrate 10 reaches the first portion 231 when the semiconductor device 100 is turned off, etc. １４ / cm ３ By setting the value to be equal to or less than this, it is possible to prevent the integral value of the hydrogen donor concentration in the high concentration region 20 from becoming too high.

[0136] The lower limit of the hydrogen donor concentration in the first portion 231 is 7×10 １３ / cm ３ may be 1×10 １４ / cm ３ As described in FIG. 7, the hydrogen donor concentration may be 1×10 １４ / cm ３ In the above region, the hydrogen donor increase rate is almost constant regardless of the oxygen concentration and carbon concentration of the semiconductor substrate 10. １４ / cm ３ By increasing the above-mentioned regions, the variations in the carrier concentration and the hydrogen donor concentration can be further suppressed. The lower limit of the hydrogen donor concentration in the first portion 231 is 1.1×10 １４ / cm ３ may be 1.2 × 10 １４ / cm ３ The upper limit of the hydrogen donor concentration in the first portion 231 may be 1.4×10 １４ / cm ３ may be 1.3×10 １４ / cm ３ may be.

[0137] In the depth direction, the length of the first portion 231 may be 60% or more, 70% or more, 80% or more, or 90% or more of the length of the high-concentration region 20. By increasing the size of the first portion 231, it is possible to further suppress variations in the carrier concentration and hydrogen donor concentration in the high-concentration region 20. At least a part of the first portion 231 may be located closer to the upper surface 21 than the center of the high-concentration region 20 in the depth direction. The high-concentration region 20 has a hydrogen donor concentration of 1.5×10１４ / cm ３ The hydrogen donor concentration of the high concentration peak may be greater than 5×10. １４ / cm ３ or more, and may be 7×10 １４ / cm ３ or more, and may be 1×10 １５ / cm ３ Of the multiple hydrogen donor concentration peaks 222, one or more hydrogen donor concentration peaks 222 closest to the lower surface 23 of the semiconductor substrate 10 may be high-concentration peaks. In the example of Figure 9, hydrogen donor concentration peaks 222-1 and hydrogen donor concentration peaks 222-2 are high-concentration peaks, but the three hydrogen donor concentration peaks 222 closest to the lower surface 23 of the semiconductor substrate 10 may be high-concentration peaks, or four or more hydrogen donor concentration peaks 222 may be high-concentration peaks.

[0138] In the high-concentration region 20, the region from the shallowest donor concentration peak (hydrogen donor concentration peak 222-1) to the deepest donor concentration peak (hydrogen donor concentration peak 222-k) is defined as the second portion 232. The positions (Z1, Zk) of the apexes of the peaks may be defined as the end positions of the second portion 232 in the depth direction. The second portion 232 may include a part of the first portion 231 or the entire first portion 231. In the depth direction, the length of the first portion 231 may be 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more of the length of the second portion 232. By increasing the size of the first portion 231, variations in the carrier concentration and hydrogen donor concentration in the high-concentration region 20 can be further suppressed.

[0139] The minimum hydrogen donor concentration in the second portion 232 is 7×10 １３ / cm ３ That is, the entire second portion 232 may be 7×10 １３ / cm ３ The second portion 232 may have a hydrogen donor concentration of 1×10 or more. This can further reduce variations in the carrier concentration and the hydrogen donor concentration. １４ / cm３ or more, and may be 1.1 × 10 １４ / cm ３ or more, and may be 1.2 × 10 １４ / cm ３ It may be more than that.

[0140] 10 is a diagram showing another example of the hydrogen donor concentration distribution in the high concentration region 20. In this example, the high concentration region 20 has a hydrogen donor concentration of 7×10 １３ / cm ３ The third portion 233 has a third portion 233 in which the portions where the distance between the first portion 231 and the third portion 233 is less than 1 / 2 are continuous in the depth direction. That is, the third portion 233 has a predetermined length in the depth direction. A plurality of the third portions 233 may be arranged discretely in the depth direction. In the example of Fig. 10, the first portion 231 and the third portion 233 are alternately arranged in a repeated manner two or more times in the depth direction. The first portion 231 and the third portion 233 may be alternately arranged in a repeated manner three or more times, or may be alternately arranged in a repeated manner four or more times.

[0141] In this example, the length of the third portion 233 in the depth direction is 15 μm or less. When a plurality of third portions 233 are provided, the length of each of the third portions 233 may be 15 μm or less, and the total length of the third portions 233 may be 15 μm or less. Furthermore, the length of each of the third portions 233 or the total length may be 10 μm or less, or 5 μm or less. This makes it possible to suppress variations in the carrier concentration and the hydrogen donor concentration.

[0142] The length of each of the third portions 233 or the total length thereof may be 20% or less, 15% or less, or 10% or less of the depth direction length of the high-concentration region 20. This makes it possible to suppress variations in the carrier concentration and the hydrogen donor concentration. The length of each of the third portions 233 or the total length thereof may be 20% or less, 15% or less, or 10% or less of the depth direction length of the first portions 231.

[0143] FIG. 11 is an enlarged view of hydrogen chemical concentration peak 202-m. The width of hydrogen chemical concentration peak 202-m in the depth direction is defined as hydrogen peak width Wpm. The hydrogen peak width Wpm is the depth direction length of the portion of hydrogen chemical concentration peak 202 where the hydrogen chemical concentration is α times or more the maximum value Hpm. α may be 0.1 (10%), 0.2 (20%), or 0.5 (50%). In the example of FIG. 11, α is 0.1. When the hydrogen chemical concentration of at least one of the two hydrogen chemical concentration valleys 204-(m-1), 204-m sandwiching hydrogen chemical concentration peak 202-m in the depth direction is greater than α×Hpm, the position where the hydrogen chemical concentration in that valley is at its minimum value is defined as the end position of the hydrogen peak width Wpm. When the valley has a flat portion that continues in the depth direction from the portion where the hydrogen chemical concentration is at a minimum, the center position of the flat portion in the depth direction may be taken as the end position of the hydrogen peak width Wpm. While the peak width of the hydrogen chemical concentration peak 202 has been described in Figure 11, the peak widths of the carrier concentration peak 212 and the hydrogen donor concentration peak 222 may also be determined in a similar manner using the respective concentration values ​​Cpm and Dpm.

[0144] The sum of the hydrogen peak widths Wpm of the multiple hydrogen chemical concentration peaks 202 in the high-concentration region 20 may be 30% or more of the depth direction length of the high-concentration region 20. This can improve the density of the hydrogen donor concentration peaks 222 in the high-concentration region 20, and as described in FIG. 7 , can suppress variations in the carrier concentration and hydrogen donor concentration. The sum of the hydrogen peak widths Wpm may be 40% or more, 50% or more, 60% or more, or 70% or more of the depth direction length of the high-concentration region 20. In the example of FIG. 11 , the sum of the peak widths of the hydrogen chemical concentration peaks 202 is used for the description. However, instead of the sum of the peak widths of the hydrogen chemical concentration peaks 202, the sum of the peak widths of the carrier concentration peaks 212 or the sum of the peak widths of the hydrogen donor concentration peaks 222 may be used.

[0145] 8, hydrogen chemical concentration peaks 202 (referred to as "same-concentration peaks") having similar hydrogen chemical concentrations may be arranged consecutively in the depth direction in high-concentration region 20. Each same-concentration peak has a hydrogen chemical concentration that is 0.8 to 1.2 times the hydrogen chemical concentration of at least one hydrogen chemical concentration peak 202 adjacent to it in the depth direction. For example, if the hydrogen chemical concentration Hpm of hydrogen chemical concentration peak 202-m is 0.8 to 1.2 times the hydrogen chemical concentration Hp(m-1) of hydrogen chemical concentration peak 202-(m-1) and / or the hydrogen chemical concentration Hp(m+1) of hydrogen chemical concentration peak 202-(m+1), then hydrogen chemical concentration peak 202-m is a same-concentration peak.

[0146] In the high-concentration region 20, the upper region 242, or the first portion 231, three or more identical concentration peaks may be arranged consecutively in the depth direction. Four or more identical concentration peaks may be arranged consecutively, or five or more identical concentration peaks may be arranged consecutively. The intervals between the identical concentration peaks may be constant or may not be constant. In the examples described herein using the identical concentration peak of the hydrogen chemical concentration peak 202, the identical concentration peak of the carrier concentration peak 212 or the identical concentration peak of the hydrogen donor concentration peak 222 may be used instead of the identical concentration peak of the hydrogen chemical concentration peak 202. The concentrations of the carrier concentration peak 212 and the hydrogen donor concentration peak 222 are also 0.8 to 1.2 times higher than the concentration of at least one concentration peak adjacent to them in the depth direction.

[0147] Fig. 12 is a diagram showing the hydrogen donor concentration distribution. The hydrogen donor concentration distribution in Fig. 12 is the same as the hydrogen donor concentration distribution in the example of Fig. 8. The high-concentration region 20 in this example has a lower region 241 and an upper region 242. The lower region 241 is a region on the lower surface 23 side of a predetermined boundary position Zb in the depth direction, and the upper region 242 is a region on the upper surface 21 side of the boundary position Zb.

[0148] The boundary position Zb may be a position 20 μm away from the lower surface 23 of the semiconductor substrate 10 in the depth direction, may be a central position in the depth direction of the high concentration region 20, may be the position of the hydrogen chemical concentration valley 204-3, or may be a position 25% away from the lower surface 23 of the semiconductor substrate 10 in the thickness direction of the semiconductor substrate 10. In an embodiment including at least one of the lower region 241 and the upper region 242 described in this specification, either of the above-mentioned boundary positions Zb may be used.

[0149] In this example, the boundary position Zb is, for example, 20 μm away from the lower surface 23 of the semiconductor substrate 10 in the depth direction. That is, the upper region 242 is a portion of the high-concentration region 20 that is 20 μm or more away from the lower surface 23 of the semiconductor substrate 10 in the depth direction. In the upper region 242, three or more of the same concentration peaks described in FIG. 11 may be arranged consecutively in the depth direction. Four or more, or even five or more, of the same concentration peaks may be arranged consecutively in the depth direction in the upper region 242. More than half, three-quarters or more, or all of the hydrogen donor concentration peaks 222 included in the upper region 242 may be the same concentration peak. By arranging the same concentration peaks in the upper region 242, the number of protruding concentration peaks in the upper region 242 is reduced, thereby suppressing surge voltages that may occur when a space charge region reaches the upper region 242.

[0150] The sum of the hydrogen peak widths Wpm (see FIG. 11 ) of the hydrogen chemical concentration peaks 202 located in the upper region 242 may be 30% or more of the depth length of the upper region 242. The sum of the hydrogen peak widths Wpm in the upper region 242 may be 40% or more, 50% or more, 60% or more, or 70% or more of the depth length of the upper region 242.

[0151] 9 , three or more identical concentration peaks may be arranged consecutively in the depth direction. Four or more identical concentration peaks may be arranged consecutively in the depth direction in the first portion 231, or five or more identical concentration peaks may be arranged consecutively in the depth direction in the first portion 231. Half or more of the hydrogen donor concentration peaks 222 included in the first portion 231 may be identical concentration peaks, three-quarters or more may be identical concentration peaks, or all of them may be identical concentration peaks.

[0152] The sum of the hydrogen peak widths Wpm (see FIG. 11 ) of the hydrogen chemical concentration peaks 202 located in the first portion 231 may be 30% or more of the length in the depth direction of the first portion 231. The sum of the hydrogen peak widths Wpm in the first portion 231 may be 40% or more of the length in the depth direction of the first portion 231, 50% or more, 60% or more, or 70% or more.

[0153] 50% or more of the depth of the upper region 242 may be the first portion 231. 60% or more of the depth of the upper region 242 may be the first portion 231, 70% or more, 80% or more, 90% or more, or the entire upper region 242 may be the first portion 231. By arranging the first portion 231 in the upper region 242, it is possible to suppress a surge voltage when a space charge region reaches the upper region 242.

[0154] FIG. 13 shows other examples of the hydrogen chemical concentration distribution and the hydrogen donor concentration distribution. The carrier concentration distribution is a distribution obtained by adding the bulk donor concentration DB to the hydrogen donor concentration distribution. In this example, the hydrogen chemical concentration varies significantly between hydrogen chemical concentration peak 202-3 and hydrogen chemical concentration peak 202-4. Hydrogen chemical concentration peak 202-3 is an example of a third hydrogen concentration peak. The hydrogen chemical concentration of hydrogen chemical concentration peak 202-3 may be 1.5 times or more, 2 times or more, 5 times or more, or 10 times or more than the hydrogen chemical concentration of hydrogen chemical concentration peak 202-4. The hydrogen donor concentration of hydrogen donor concentration peak 222-3 may be 1.5 times or more, 2 times or more, 5 times or more, or 10 times or more than the hydrogen donor concentration of hydrogen donor concentration peak 222-4. The other distributions are similar to the examples described with reference to FIGS. 4 to 12.

[0155] In this example, among the multiple hydrogen donor concentration peaks 222, the hydrogen donor concentration peak 222-(k-1) that is second closest to the upper surface 21 of the semiconductor substrate 10 is defined as the second deep donor concentration peak. The hydrogen donor concentration peak 222-(k-1) has a hydrogen donor concentration n1, and the hydrogen donor concentration valley 224-(k-1) has a hydrogen donor concentration n2. The hydrogen donor concentration peak 222-(k-1) and the hydrogen donor concentration valley 224-(k-1) may be included in the first portion 231 (see FIG. 9 ). The value n1 / n2 obtained by dividing the hydrogen donor concentration n1 by the hydrogen donor concentration n2 may be 1.1 or more and 2.0 or less. This allows the hydrogen donor concentration peak 222-(k-1), which has a relatively small amplitude, to be located between the hydrogen donor concentration peak 222-k and the hydrogen donor concentration peak 222-4, as compared to the reference example shown in FIG. 4 . This makes it possible to suppress variations in the carrier concentration and hydrogen donor concentration between the hydrogen donor concentration peak 222-k and the hydrogen donor concentration peak 222-4. The value n1 / n2 may be 1.2 or greater, or may be 1.3 or greater. The value n1 / n2 may be 1.9 or less, or may be 1.8 or less. The contents described regarding the value n1 / n2 can also be applied to configurations other than those shown in FIG. 13.

[0156] In this example, boundary position Zb between upper region 242 and lower region 241 is the position of hydrogen chemical concentration valley 204-3 or hydrogen donor concentration valley 224-3. In other words, lower region 241 is the region from bottom surface 23 of semiconductor substrate 10 to the region including hydrogen chemical concentration peak 202-3, and upper region 242 is the region closer to top surface 21 of semiconductor substrate 10 than hydrogen chemical concentration peak 202-3.

[0157] Of the hydrogen donor concentration peaks 222 in the lower region 241, the hydrogen donor concentration peak 222-3 that is farthest from the lower surface 23 of the semiconductor substrate 10 is referred to as the "lower deepest donor concentration peak." Of the hydrogen donor concentration valleys 224 in the lower region 241, the hydrogen donor concentration valley 224-2 that is farthest from the lower surface 23 of the semiconductor substrate 10 is referred to as the "lower deepest donor concentration valley." The hydrogen donor concentration of the hydrogen donor concentration peak 222-3 is designated N1, and the hydrogen donor concentration of the hydrogen donor concentration valley 224-2 is designated N2. The value N1 / N2 obtained by dividing the hydrogen donor concentration N1 by the hydrogen donor concentration N2 may be 1.2 or more and 4.0 or less. This allows the hydrogen donor concentration peak 222, which has a relatively large amplitude, to be located in the lower region 241, preventing the space charge region from reaching the collector region 22. The value N1 / N2 may be equal to or greater than 2, and may be equal to or greater than 2.5. The value N1 / N2 may be equal to or less than 3.5, and may be equal to or less than 3. The description regarding the value N1 / N2 can also be applied to configurations other than those shown in FIG. 13 .

[0158] Let a be the value N1 / N2 and b be the value n1 / n2. The value a / b obtained by dividing the value a by the value b may be greater than 0.5. The value a / b may be greater than 1, or may be 2 or greater.

[0159] The hydrogen donor concentration n1 may be 0.5 times or less the hydrogen donor concentration N1. This allows low-concentration hydrogen donor concentration peaks 222 to be located in the upper region 242. All of the hydrogen donor concentration peaks 222 included in the upper region 242 may have the hydrogen donor concentration n1. The hydrogen donor concentration n1 may be 0.2 times or less, or may be 0.1 times or less, the hydrogen donor concentration N1.

[0160] 14 is a diagram showing another example of the hydrogen chemical concentration distribution and the hydrogen donor concentration distribution. In this example, the boundary position Zb between the lower region 241 and the upper region 242 is the center in the depth direction of the high-concentration region 20. In other words, the region of the high-concentration region 20 closer to the lower surface 23 than the center in the depth direction is defined as the lower region 241, and the region closer to the upper surface 21 is defined as the upper region 242.

[0161] In this example, the hydrogen donor concentration of at least one hydrogen donor concentration valley 224 in the upper region 242 is higher than the hydrogen donor concentration of at least one hydrogen donor concentration valley 224 in the lower region 241. The hydrogen donor concentration of at least one hydrogen donor concentration valley 224 in the first portion 231 (see FIG. 9 ) included in the upper region 242 may be higher than the hydrogen donor concentration of at least one hydrogen donor concentration valley 224 in the lower region 241.

[0162] 14 , the hydrogen donor concentration of the hydrogen donor concentration valley 224-1 is the minimum value Dmin of the hydrogen donor concentration in the lower region 241. The hydrogen donor concentration of at least one hydrogen donor concentration valley 224 in the upper region 242 (or the first portion 231 of the upper region 242) is greater than the minimum value Dmin. The hydrogen donor concentrations of multiple hydrogen donor concentration valleys 224 in the upper region 242 (or the first portion 231 of the upper region 242) may be greater than the minimum value Dmin, or the hydrogen donor concentrations of more than half of the hydrogen donor concentration valleys 224 in the upper region 242 (or the first portion 231 of the upper region 242) may be greater than the minimum value Dmin, or the hydrogen donor concentrations of all the hydrogen donor concentration valleys 224 in the upper region 242 (or the first portion 231 of the upper region 242) may be greater than the minimum value Dmin. This increases the hydrogen donor concentration in the upper region 242, thereby suppressing variations in the carrier concentration and hydrogen donor concentration.

[0163] 15 is a diagram showing an example of the boundary position Zb. In this example, the boundary position Zb is a position 20 μm away from the lower surface 23 of the semiconductor substrate 10 in the depth direction. The value obtained by integrating the hydrogen donor concentration in the upper region 242 in the depth direction is defined as the integrated concentration S ( / cm ２) The integral density S corresponds to the area of ​​the hatched portion in FIG. 15. In this example, the integral density S is 8×10 １０ / cm ２ That's it, 2 x 10 １１ / cm ２ The following is the result.

[0164] This increases the hydrogen donor concentration in the upper region 242 to a certain extent, thereby suppressing variations in the carrier concentration and hydrogen donor concentration. Furthermore, the hydrogen donor concentration in the upper region 242 is prevented from becoming too high, thereby suppressing surge voltages that occur when the space charge region reaches the upper region 242. The integral concentration S is 1×10 １１ / cm ２ or more, and may be 1.2 × 10 １１ / cm ２ The integral concentration S may be 1.8×10 １１ / cm ２ may be equal to or less than 1.6×10 １１ / cm ２ It may be the following:

[0165] Of the hydrogen chemical concentration peaks 202 in the upper region 242, the hydrogen chemical concentration at the apex is 5×10 １５ / cm ３ The sum of the full widths at half maximum of the hydrogen chemical concentration peaks 202 may be 20% or more and 90% or less of the depth direction length of the upper region 242. In the first portion 231 included in the upper region 242, the sum of the full widths at half maximum of the hydrogen chemical concentration peaks 202 may be 20% or more and 90% or less of the depth direction length of the first portion 231 included in the upper region 242.

[0166] In the example of FIG. 15, for all hydrogen chemical concentration peaks 202 in the upper region 242, the hydrogen chemical concentration at the apex is 5×10 １５ / cm ３11 , when the hydrogen chemical concentration of at least one of the two hydrogen chemical concentration valleys 204 sandwiching the hydrogen chemical concentration peak 202 is greater than 50% of the hydrogen chemical concentration at the apex of the hydrogen chemical concentration peak 202, the position of the hydrogen chemical concentration valley 204 is defined as the end position of the full width at half maximum of the hydrogen chemical concentration peak 202. The sum of the full widths at half maximum of the hydrogen chemical concentration peaks 202 described above may be 30% or more, 40% or more, 50% or more, or 60% or more of the depth length of the upper region 242. In the first portion 231 included in the upper region 242, the sum of the full widths at half maximum of the hydrogen chemical concentration peaks 202 described above may be 40% or more, 50% or more, or 60% or more of the depth length of the first portion 231 included in the upper region 242.

[0167] Of the hydrogen donor concentration peaks 222 in the upper region 242, the hydrogen donor concentration at the apex is 7×10 １３ / cm ３ The sum of the full widths at half maximum of the hydrogen donor concentration peaks 222, which are equal to or greater than 100%, may be 30% or more of the length in the depth direction of the upper region 242. In the first portion 231 included in the upper region 242, the sum of the full widths at half maximum of the hydrogen donor concentration peaks 222 may be 30% or more of the length in the depth direction of the first portion 231 included in the upper region 242.

[0168] 11 , when the hydrogen donor concentration of at least one of the two hydrogen donor concentration valleys 224 sandwiching the hydrogen donor concentration peak 222 is greater than 50% of the hydrogen donor concentration at the apex of the hydrogen donor concentration peak 222, the position of the hydrogen donor concentration valley 224 is defined as the end position of the full width at half maximum of the hydrogen donor concentration peak 222. The sum of the full widths at half maximum of the hydrogen donor concentration peaks 222 described above may be 40% or more, 50% or more, 60% or more, or 70% or more of the length of the upper region 242 in the depth direction. The sum of the full widths at half maximum of the hydrogen donor concentration peaks 222 described above may be 90% or less of the length of the upper region 242 in the depth direction. In the first portion 231 included in the upper region 242, the sum of the full widths at half maximum of the above-mentioned hydrogen donor concentration peaks 222 may be 40% or more of the depth direction length of the first portion 231 included in the upper region 242, 50% or more, 60% or more, or 70% or more.

[0169] FIG. 16 is a diagram showing another example of the boundary position Zb. In this example, the thickness of the semiconductor substrate 10 in the depth direction is Tb. In this example, the boundary position Zb is a position where the distance from the lower surface 23 of the semiconductor substrate 10 is 25% (0.25×Tb) of the thickness of the semiconductor substrate 10. In this example, the upper region 242 is provided in at least a portion of the range where the distance from the lower surface 23 of the semiconductor substrate 10 is 0.25×Tb or more and 0.5×Tb or less. In this example, the entire upper region 242 is located in a depth range from 0.25×Tb to 0.5×Tb. The upper region 242 may be provided throughout the entire depth range from 0.25×Tb to 0.5×Tb. If the high-concentration region 20 extends toward the upper surface 21 beyond the depth position 0.5×Tb, the region from 0.25×Tb to 0.5×Tb may be defined as the upper region 242.

[0170] The structure other than the position of the upper region 242 is the same as any of the examples described in the drawings in this specification. For example, the integrated concentration S in the upper region 242, the sum of the peak widths of the hydrogen chemical concentration peaks 202, and the sum of the peak widths of the hydrogen donor concentration peaks 222 may be the same as the example in FIG.

[0171] In each example described in each figure of this specification, the carbon concentration of the semiconductor substrate 10 is 1×10 １３ / cm ３ That's it, 5 x 10 １５ / cm or less. The average carbon concentration in the entire semiconductor substrate 10 may be used as the carbon concentration of the semiconductor substrate 10. The carbon concentration of the semiconductor substrate 10 may be 5×10 １３ / cm ３ or more, and may be 1×10 １４ / cm ３ The carbon concentration of the semiconductor substrate 10 may be 3×10 １５ / cm ３ may be equal to or less than 1×10 １５ / cm ３ It may be the following:

[0172] The hydrogen donors in the high-concentration region 20 may include interstitial donors Si—H. As an example, the hydrogen donors in the high-concentration region 20 include VOH defects and interstitial donors SiH. The concentration of the interstitial donors in the high-concentration region 20 may be 30% or more of the concentration of the hydrogen donors. The value obtained by integrating the concentration of the interstitial donors in the high-concentration region 20 in the depth direction may be 30% or more, 40% or more, or 50% or more of the value obtained by integrating the hydrogen donor concentration in the high-concentration region 20 in the depth direction. The degree to which the interstitial donors Si—H are formed is relatively little affected by the oxygen concentration and carbon concentration of the semiconductor substrate 10. Therefore, by increasing the ratio of the interstitial donors Si—H, variations in the carrier concentration and hydrogen donor concentration in the high-concentration region 20 can be suppressed. The value obtained by integrating the concentration of interstitial donors in the first portion 231 in the depth direction may be 30% or more, 40% or more, or 50% or more of the value obtained by integrating the concentration of hydrogen donors in the depth direction in the first portion 231. As an example, the concentration of interstitial donors Si—H may be determined by fitting the peak portion of the carrier concentration distribution with a Gaussian and subtracting the bulk donor concentration DB.

[0173] 17 is a cross-sectional view taken along the line e-e showing an example of a semiconductor device 100A according to another embodiment of the present invention. Each of the examples described in FIGS. 1 to 16 can be combined with the semiconductor device 100A shown in FIG. 17 and subsequent figures, and some of the components of each of the examples described in FIGS. 1 to 16 can be extracted and applied to the semiconductor device 100A. Also, some of the components of the semiconductor device 100A can be extracted and applied to the semiconductor device 100 described in FIGS. 1 to 16.

[0174] 1 to 16 , the semiconductor device 100A may further include at least one of the N-type second high concentration region 26, the P-type electric field relaxation region 89, the P-type floating region 84, and the P-type second cathode region 87. However, the second high concentration region 26, the P-type electric field relaxation region 89, the P-type floating region 84, and the P-type second cathode region 87 are not essential for the semiconductor device 100A. The semiconductor device 100A may include one of these, multiple of these, all of these, or none of these.

[0175] The electric field relaxation region 89 may be electrically floating. The electric field relaxation region 89 may be in contact with the bottom of at least one gate trench portion 40. The electric field relaxation region 89 may cover the bottom of the gate trench portion 40. By providing the electric field relaxation region 89, it is possible to relax the electric field concentration at the bottom of the trench portion. A drift region 18 may be provided between the electric field relaxation region 89 and the base region 14. In the example of FIG. 17 , the drift region 18 is provided between the electric field relaxation region 89 and the accumulation region 16.

[0176] The electric field relaxation region 89 may be provided for all gate trench portions 40. The electric field relaxation region 89 may or may not be provided for the dummy trench portion 30. In the example of FIG. 17 , the electric field relaxation region 89 is provided for the dummy trench portion 30 sandwiched between two gate trench portions 40. The electric field relaxation region 89 may be provided continuously across a plurality of trench portions arranged side by side in the X-axis direction. At least one electric field relaxation region 89 may be provided for each transistor portion 70. The electric field relaxation region 89 may or may not be provided for the diode portion 80.

[0177] The second high concentration region 26 is a region having a higher doping concentration than the drift region 18. The second high concentration region 26 may have a concentration peak of a hydrogen donor, or may have a concentration peak of another donor. In this example, the second high concentration region 26 is provided on the upper surface 21 side of the semiconductor substrate 10. In this example, the second high concentration region 26 is located below the bottom of the trench portion. The second high concentration region 26 may be located below the electric field relaxation region 89. The second high concentration region 26 may or may not be in contact with the electric field relaxation region 89. In this example, the drift region 18 is provided between the second high concentration region 26 and the electric field relaxation region 89.

[0178] The floating region 84 is provided above the cathode region 82. The floating region 84 may be separated from the collector region 22. The floating region 84 may be provided between the high-concentration region 20 and the cathode region 82. The end of the floating region 84 on the transistor section 70 side may be located inside the cathode region 82 in a top view. By providing the floating region 84, carrier injection from the cathode region 82 can be suppressed, and the characteristics of the diode section 80 can be adjusted.

[0179] The second cathode region 87 is arranged alongside the cathode region 82 in the X-axis direction. In the diode section 80 of this example, the cathode region 82 and the second cathode region 87 are arranged alternately multiple times in the X-axis direction. By providing the second cathode region 87, the area of ​​the cathode region 82 is limited, and carrier injection from the underside of the diode section 80 is suppressed, thereby enabling the characteristics of the diode section 80 to be adjusted.

[0180] In the semiconductor device 100A, the dopant of the bulk donor in the semiconductor substrate 10 may be antimony. In each of the examples of FIGS. 1 to 16 , the bulk donor may also be antimony. The primary dopant in the drift region 18 may be antimony. For example, the primary dopant in a region may be the dopant with the highest doping concentration that determines the conductivity type of the region, among one or more dopants that impart N-type or P-type conductivity to the region. If the drift region 18 is N-type, the primary dopant in the drift region 18 is the N-type dopant with the highest doping concentration. The doping concentration of each dopant may be calculated by dividing the integral concentration of the doping concentration in the drift region 18 in the depth direction by the distance of the depth range over which the integration is performed. The doping concentration of a dopant may be calculated by multiplying the chemical concentration of the dopant by the electrical activation rate. When the dopant is phosphorus, antimony, arsenic, or boron, the value of the electrical activation rate is 95% or more, and the electrical activation rate may be substantially 100%.

[0181] The net doping concentration of the drift region 18 may be the sum of the doping concentrations of one or more dopants that exhibit N-type or P-type conductivity in the drift region 18, where the doping concentration of the N-type dopant (i.e., donor concentration) is + and the doping concentration of the P-type dopant (i.e., acceptor concentration) is −. That is, the donor concentrations of i types of N-type dopants are expressed as ΣN Ｄ (i) The acceptor concentration of j kinds of P-type dopants is ΣN Ａ (j), the net doping concentration N of the drift region 18 is N=ΣN Ｄ(i) -ΣN Ａ (j). Note that Σ is a symbol for summation, and the subscript i or j that should be written below each symbol Σ is omitted. As an example, if there are two types of N-type dopants in the drift region 18 and two types of P-type dopants in the drift region 18, the net doping concentration N of the drift region 18 is N = N Ｄ (1) + N Ｄ (2) - {N Ａ (1) + N Ａ The net doping concentration N of the drift region 18 may be the net doping concentration N of the entire drift region 18, or may be the net doping concentration N in a partial depth region of the drift region 18. The main dopant in the drift region 18 is N Ｄ The dopant with the largest value of (i) is the dopant.

[0182] The primary dopant in drift region 18 may be a bulk donor distributed throughout semiconductor substrate 10, and the bulk donor may be antimony. The primary dopant in drift region 18 may be the primary dopant at any depth position in drift region 18 throughout semiconductor device 100 in top view, or may be the primary dopant over 90% or more of the entire area of ​​semiconductor device 100 in top view.

[0183] Fig. 18A is a diagram showing an example of the doping concentration distribution along line gg in Fig. 17. Line gg is a line that passes through the electric field relaxation region 89 and is parallel to the Z axis. The horizontal axis in Fig. 18A indicates the depth position (position in the Z axis direction) within the semiconductor substrate 10. In Fig. 18A, the upper surface 21 of the semiconductor substrate 10 is set as the reference position.

[0184] Each of the emitter region 12, the base region 14, the accumulation region 16, and the field relaxation region 89 has one or more concentration peaks. In this example, the accumulation region 16 and the field relaxation region 89 are in contact with each other.

[0185] The drift region 18 of this example is provided from the lower end of the electric field relaxation region 89 to the upper end of the high concentration region 20. The semiconductor substrate 10 of this example does not have the second high concentration region 26. The drift region 18 may have a substantially uniform doping concentration from the lower end of the electric field relaxation region 89 to the upper end of the high concentration region 20. In another example, the drift region 18 may have a substantially uniform doping concentration from the lower end of the second high concentration region 26 to the upper end of the high concentration region 20. "Substantially uniform" may mean that the maximum value of the doping concentration is 200% or less of the minimum value of the doping concentration, or may mean that the maximum value is 150% or less, or may mean that the maximum value is 130% or less, or may mean that the maximum value is 110% or less.

[0186] The high-concentration region 20 has one or more doping concentration peaks 213 in the depth direction. The doping concentration peaks 213 correspond to the carrier concentration peaks 212 described with reference to FIGS. 1 to 16 . The high-concentration region 20 may have four or fewer doping concentration peaks 213 as shown in FIG. 18A , or may have more than four doping concentration peaks 213. The high-concentration region 20 may have the same structure as any of the examples described with reference to FIGS. 1 to 16 . In this example, the length of the drift region 18 in the depth direction is Wd (μm), and the length of the high-concentration region 20 in the depth direction is Wfs (μm).

[0187] A collector region 22 is provided between the high concentration region 20 and the lower surface 23. In the diode section 80, a cathode region 82 or a second cathode region 87 is provided instead of the collector region 22.

[0188] In this specification, a predetermined range in the depth direction of the semiconductor substrate 10 may be referred to as a first depth range 191. Furthermore, a predetermined range in the depth direction of the drift region 18 may be referred to as a second depth range 192. The first depth range 191 and the second depth range 192 will be described later.

[0189] Fig. 18B is a diagram showing an example of the chemical concentration distribution of each dopant along line gg in Fig. 17. However, Fig. 18B also shows the chemical concentration distribution of the dopant in the cathode region 82. The example in Fig. 18B shows the distributions of hydrogen H, phosphorus P, boron B, antimony Sb, and arsenic As in the semiconductor substrate 10.

[0190] The bulk donor of the semiconductor substrate 10 in this example is antimony. The chemical concentration of antimony is approximately uniform inside the semiconductor substrate 10. As shown in FIG. 19, the chemical concentration of antimony contained in the semiconductor substrate 10 is 1×10 １２ / cm ３ That's it, 1 x 10 １４ / cm ３ It may be the following:

[0191] The primary dopant in drift region 18 is antimony. In this example, drift region 18 does not have any chemical concentration peaks of dopants other than antimony. Throughout the entire depth of drift region 18, the chemical concentration of antimony may be higher than the chemical concentrations of any other dopants.

[0192] A hydrogen donor may be used as the main dopant in the high concentration region 20. The hydrogen chemical concentration contained in the semiconductor substrate 10 is 1×10 １５ / cm ３ That's it, 5 x 10 １８ / cm ３ The chemical concentration of each dopant may be a peak value.

[0193] Boron may be used as a main dopant in the base region 14, the well region 11, or the contact region 15. The boron chemical concentration in the semiconductor substrate 10 is 1×10 １６ / cm ３ That's it, 1 x 10 １９ / cm ３ It may be the following:

[0194] Phosphorus may be used as the primary dopant in the cathode region 82 or the accumulation region 16. The phosphorus chemical concentration in the semiconductor substrate 10 is 1×10 １６ / cm ３ That's it, 5 x 10 １９ / cm ３ It may be the following:

[0195] Arsenic may be used as the primary dopant in the emitter region 12. The chemical concentration of arsenic contained in the semiconductor substrate 10 is 1×10 １９ / cm ３ That's it, 1 x 10 ２０ / cm ３ The magnitude relationship of the chemical concentrations of the dopants contained in the semiconductor substrate 10 may be antimony chemical concentration<hydrogen chemical concentration<boron chemical concentration or phosphorus chemical concentration<arsenic chemical concentration.

[0196] The average concentration of antimony chemical concentration in the first depth range 191 of the semiconductor substrate 10 is denoted by <Nsb>, and the standard deviation of the antimony chemical concentration in the first depth range 191 is denoted by <ΔNsb>. The thickness of the first depth range 191 may be 50% or more, 60% or more, or 70% or more of the thickness of the semiconductor substrate 10. The thickness of the first depth range 191 may be 100% or less, less than 100%, 90% or less, or 80% or less of the thickness of the semiconductor substrate 10.

[0197] The ratio R of the standard deviation <ΔNsb> of the antimony chemical concentration to the average concentration <Nsb> of the antimony chemical concentration is defined as R = <ΔNsb> / <Nsb>. The ratio R may be 0.2 or less, 0.15 or less, 0.1 or less, or 0.08 or less. The ratio R may be 0.001 or more, 0.01 or more, or 0.03 or more. For example, the ratio R in the first depth range 191 being 0.2 or less means that there exists a first depth range 191 in which the ratio R is 0.2 or less. Furthermore, the thickness of the first depth range 191 being, for example, 50% or more of the thickness of the semiconductor substrate 10 means that there exists a first depth range 191 that satisfies the above condition of the ratio R and is 50% or more of the thickness of the semiconductor substrate 10.

[0198] The upper end of the first depth range 191 may or may not coincide with the upper surface 21 of the semiconductor substrate 10. The lower end of the first depth range 191 may or may not coincide with the lower surface 23 of the semiconductor substrate 10. The first depth range 191 includes at least a portion of the drift region 18 in the depth direction. The first depth range 191 may include half or more of the drift region 18 in the depth direction, or may include the entire drift region 18.

[0199] In the depth direction of the semiconductor substrate 10, the thickness of the drift region 18 may be 20% or more and 90% or less of the thickness of the semiconductor substrate 10. The thickness of the drift region 18 may be 40% or more, 50% or more, or 60% or more of the thickness of the semiconductor substrate 10.

[0200] 19 is a diagram showing the distribution of antimony chemical concentration in a second depth range 192 of the drift region 18. The average concentration of antimony chemical concentration in the second depth range 192 is defined as <Nsb_d>, and the standard deviation of the antimony chemical concentration in the second depth range 192 is defined as <ΔNsb_d>. The thickness of the second depth range 192 is 50% or more and 100% or less of the thickness Wd of the drift region 18. The thickness of the second depth range 192 may be 70% or more, 80% or more, or 90% or more of the thickness of the drift region 18.

[0201] The ratio Rd of the standard deviation <ΔNsb_d> of antimony chemical concentration to the average concentration <Nsb_d> of antimony chemical concentration is defined as Rd = <ΔNsb_d> / <Nsb_d>. The ratio Rd may be 0.2 or less, 0.15 or less, 0.1 or less, or 0.08 or less. The ratio Rd may be 0.001 or more, 0.01 or more, or 0.03 or more. Since the donor conversion rate of antimony is 95% or more of the antimony chemical concentration, the above ratio Rd may be the ratio of donor concentration or doping concentration.

[0202] 1 to 16, in semiconductor device 100 or semiconductor device 100A, the impurity elements and their concentrations added to semiconductor substrate 10 affect variations in the characteristics of each element at the product stage. Semiconductor device 100A provides a configuration that suppresses variations in the characteristics of each element at the product stage and enables cost reduction.

[0203] As shown in FIG. 19 , by reducing the ratio Rd, which indicates the variation in the primary dopant, the variation in the doping concentration in the second depth range 192 can be reduced. This can suppress the variation in the characteristics of the semiconductor device 100A. In the drift region 18, dopants other than bulk donors may be almost absent. For example, in the drift region 18, the concentration of bulk donors may be two or more times, five or more times, or even ten or more times the concentration of other dopants. Therefore, by suppressing the variation in the concentration of bulk donors, which are the primary dopants in the drift region 18, the variation in the doping concentration in the drift region 18 can be easily suppressed. As will be described later, by using antimony as the primary dopant in the drift region 18, the ratio Rd in the drift region 18 can be easily reduced.

[0204] Variations in the characteristics of the semiconductor device 100A can also be suppressed by reducing the ratio R in the first depth range 191. By using antimony as the bulk donor, the ratio R can be easily reduced.

[0205] 20A is a flow diagram showing a method for manufacturing the semiconductor device 100A. The method for manufacturing the semiconductor device 100A includes a bulk wafer preparation step (S1010), an upper surface structure formation step (S1020), a collector region / second cathode region implantation step (S1030), a cathode region implantation step (S1040), a floating region implantation step (S1050), a first annealing step (S1060), a high concentration region implantation step (S1070), a second annealing step (S1080), and a collector electrode formation step (S1090). In this embodiment, each step is performed in ascending order of the number following the S.

[0206] FIG. 20B illustrates steps S1010 to S1030 of the manufacturing method for the semiconductor device 100A. In S1010, an N-type bulk wafer is prepared as the semiconductor substrate 10. N-type bulk donors are distributed throughout the N-type bulk wafer. The bulk donors are dopant donors uniformly contained within the ingot that forms the base of the semiconductor substrate 10 during its manufacture. In this example, the bulk donor is a volatile first element. For example, the first element is antimony. Alternatively, the first element may be arsenic. By selecting these volatile elements as the bulk donor, it is possible to adjust the concentration of impurity elements by controlling the pressure during the ingot manufacturing process. In other words, it is possible to uniformly adjust the resistivity. This improves the yield of bulk wafers that can be cut from the ingot.

[0207] In S1020, an upper surface structure 116 is formed. The upper surface structure 116 includes a mesa portion 60, a mesa portion 61, a dummy trench portion 30, a gate trench portion 40, an interlayer insulating film 38, and an emitter electrode 52. The mesa portion 60 may include an emitter region 12, a base region 14, a contact region 15, and an accumulation region 16. The mesa portion 61 may include the base region 14, the contact region 15, and the accumulation region 16. In S1020, a P-type dopant for the base region 14 may be implanted into the upper surface 21 of the N-type semiconductor substrate 10. An N-type dopant for the second high concentration region 26 may also be implanted. The second high concentration region 26 is formed on the upper surface 21 side of the semiconductor substrate 10 in the depth direction and has a higher donor concentration than the drift region 18. Then, trench portions may be formed in the semiconductor substrate 10. In the process of forming the dummy conductive portion 34 and the gate conductive portion 44 in each trench portion, a polysilicon layer of the peripheral gate wiring 130 may be further formed. The dopant contained in the semiconductor substrate 10 may be accelerated in an ion state by an implanter and implanted into the semiconductor substrate 10. The semiconductor substrate 10 may be annealed as appropriate.

[0208] In step S1020, after forming each trench portion, an N-type dopant for the accumulation region 16, an N-type dopant for the emitter region 12, and a P-type dopant for the contact region 15 may be selectively implanted in sequence. After implanting these dopants, the semiconductor substrate 10 may be annealed as appropriate. In step S1020, after implanting the dopants and annealing, an interlayer insulating film 38 may be formed by CVD. An opening including the contact hole 54 may be formed by selectively removing the interlayer insulating film 38 and the thermal oxide film on the upper surface 21 by etching. The thermal oxide film is, for example, an insulating film formed on the upper surface 21 when forming the gate insulating film 42 and the dummy insulating film 32. In step S1020, the implantation order of the dopants may be changed as appropriate.

[0209] In S1020, after forming the interlayer insulating film 38 and the contact hole 54, the emitter electrode 52 may be deposited by sputtering. When depositing the emitter electrode 52 by sputtering, the metal layer of the peripheral gate wiring 130 and the gate pad 164 may also be deposited. After depositing these metal layers, the emitter electrode 52, the metal layer of the peripheral gate wiring 130, and the gate pad may be patterned into a predetermined shape. S1020 may also include a step of forming a passivation layer including a predetermined opening on the emitter electrode 52, etc.

[0210] In S1020, a second element having a lower mass number than the first element is implanted to form the emitter region 12. The second element is, for example, arsenic. Furthermore, a third element having a lower mass number than the second element is implanted to form the accumulation region 16. The third element is, for example, phosphorus. Furthermore, a fourth element having a lower mass number than the third element is implanted to form the second high concentration region 26. The fourth element is, for example, hydrogen. The second high concentration region 26 may be formed by hydrogen ion implantation from the upper surface 21 side of the semiconductor substrate 10.

[0211] In this way, by using an element with a lower mass number for a dopant whose implantation position relative to the upper surface 21 of the semiconductor substrate 10 is deeper, it is possible to improve manufacturing efficiency and reduce damage to the semiconductor substrate 10 (e.g., silicon substrate). Also, by changing the element implanted into each layer, if contamination or the like occurs, it becomes possible to easily analyze which process caused the problem. Therefore, it is possible to achieve overall cost reduction.

[0212] The semiconductor device 100A does not need to have all of the emitter region 12, the accumulation region 16, and the second high-concentration region 26. For example, the semiconductor device 100A may not have either the accumulation region 16 or the second high-concentration region 26, or both. In this case, for example, the first element constituting the bulk wafer may be arsenic, and the second element constituting the emitter region 12 may be phosphorus. The second element is preferably lighter than the first element. That is, in this embodiment, at least the N-type bulk donor in the semiconductor substrate 10 is an element with a higher mass number than the donor locally implanted into the semiconductor substrate 10. The bulk donor may include multiple elements. Any of the multiple elements of the bulk donor may be the element with the highest mass number among the donors contained in the semiconductor substrate 10.

[0213] In S1030, a P-type dopant is implanted into the entire lower surface 23 of the semiconductor substrate 10. In S1030, a dopant may be implanted to form the collector region 22 in the transistor portion 70. That is, in S1030, the P-type dopant may be doped at a dose corresponding to the doping concentration of the collector region 22 in the semiconductor device 100A.

[0214] 20C is a diagram showing steps S1040 to S1060 of the manufacturing method of the semiconductor device 100A. In S1040, a mask 68-1 made of a photoresist material or the like is first formed in contact with the entire lower surface 23 of the semiconductor substrate 10. Thereafter, the mask 68-1 is left in an area corresponding to the collector region 22 in the XY plane. When the second cathode region 87 is formed in the diode section 80, the mask 68-1 is also left in an area corresponding to the second cathode region 87. The mask 68-1 is removed from an area corresponding to the cathode region 82.

[0215] After patterning the mask 68-1, an N-type dopant is implanted into the lower surface 23 of the semiconductor substrate 10. In S1040, a dopant for forming the cathode region 82 in the diode section 80 may be implanted. That is, in S1040, the N-type dopant may be doped at a dose corresponding to the doping concentration of the cathode region 82 in the semiconductor device 100A. In this example, in S1040, a fifth element having a mass number lower than that of the first element is implanted to form the cathode region 82. The fifth element is, for example, phosphorus or arsenic.

[0216] Since the P-type dopant is implanted into the entire lower surface 23 in S1030, a P-type region is formed across the entire lower surface 23 before the ion implantation in S1040. In S1040, an N-type dopant is counter-doped into the area where the mask 68-1 is not provided, forming an N-type region in that area. The N-type dopant does not need to be implanted into the area where the mask 68-1 is provided. After doping, the mask 68-1 may be removed.

[0217] In S1050, a P-type dopant is implanted to form floating region 84. If floating region 84 is not provided in semiconductor device 100A, S1050 may be omitted. In S1050, mask 68-2 is provided in an area other than the area corresponding to floating region 84 in the XY plane. Mask 68-2 is formed in the same manner as mask 68-1, but is provided in a different area in the XY plane from mask 68-1.

[0218] After patterning the mask 68-2, a P-type dopant is implanted into the underside 23 of the semiconductor substrate 10. In S1050, the dopant may be implanted to form the P-type floating region 84. That is, in S1050, the P-type dopant may be doped at a dose corresponding to the doping concentration of the floating region 84 in the semiconductor device 100A. The implantation depth range of the P-type dopant in S1050 may be deeper than the implantation depth range of the N-type dopant in S1040. After doping, the mask 68-2 may be removed.

[0219] The floating region 84 is a P-type region that is in an electrically floating state. The floating region 84 may be provided in the diode section 80. The floating region 84 may be provided dispersedly throughout the diode section 80. In principle, being in an electrically floating state refers to a state in which the floating region 84 is not electrically connected to either the collector electrode 24 or the emitter electrode 52. By providing the floating region 84, injection of electrons from the cathode region 82 can be suppressed. This makes it possible to adjust the carrier distribution in the depth direction of the semiconductor substrate 10 without providing a lifetime killer on the underside 23 of the semiconductor substrate 10. This reduces the cost of providing a lifetime control region. In addition, it is also possible to reduce leakage current caused by the lifetime control region.

[0220] As described above, in steps S1040 and S1050, multiple mask processes are performed for forming, patterning, and removing masks 68-1 and 68-2, respectively. Therefore, the later the implantation stage of the multiple implantation stages for implanting dopant ions, the higher the possibility of particles 86 being generated and adhering to the underside 23 of the semiconductor substrate 10. This may result in defects 88 or scratches in the semiconductor substrate 10 due to the particles 86. Defects 88 and scratches in the cathode region 82 directly affect the electrical characteristics of the diode section 80, and therefore significantly affect the characteristics of the semiconductor device 100A. For example, defects 88 and scratches in the cathode region 82 may result in junction leakage, poor breakdown voltage, and reduced switching characteristics.

[0221] In the manufacturing method of this example, S1050 is performed after S1040. As a result, the state of the lower surface 23 when S1040 is performed can be made cleaner with fewer particles 86 and the like, compared to when S1040 is performed after S1050. This reduces the risk of defects 88 or scratches occurring in the cathode region 82 in S1040. This reduces current leakage and breakdown voltage defects in the semiconductor device 100. In this way, the manufacturing method of this example can improve the yield rate of RC-IGBTs.

[0222] In the manufacturing method of this example, S1030 is performed while the lower surface 23 is clean, thereby reducing defects 88 and scratches in the collector region 22. This also reduces current leakage and breakdown voltage defects in the collector region 22. However, in this example, S1050 is performed after S1030 and S1040, so a relatively large number of particles 86 may have been generated when S1050 was performed. As a result, a relatively large number of defects 88 may be introduced into the floating region 84. However, compared to defects 88 and scratches introduced into the cathode region 82, defects 88 introduced into the floating region 84 have a smaller impact on the diode section 80. It is relatively easy to reduce the number of defects 88 introduced into the floating region 84 to an acceptable level.

[0223] In S1060, the vicinity of the lower surface 23 of the semiconductor substrate 10 is locally annealed by irradiating the lower surface 23 with laser light. The temperature of the region irradiated with the laser light in S1060 is, for example, approximately 1000° C. The laser light may have energy higher than the band gap energy of the semiconductor substrate 10. By S1060, crystal defects caused by dopant ion implantation can be repaired and the implanted dopants can be activated.

[0224] FIG. 20D illustrates steps S1070 to S1090 of the manufacturing method for the semiconductor device 100A. In S1060, a dopant is implanted to form the high-concentration region 20 (e.g., functioning as a field stop region). In this example, in S1060, a sixth element having a lower mass number than the first element and the fifth element is implanted. The sixth element is, for example, hydrogen. The hydrogen is implanted from the lower surface 23 to a predetermined depth range. Note that the hydrogen may be implanted into the semiconductor substrate 10 in the form of hydrogen ions (e.g., protons). The hydrogen ions may be implanted into the semiconductor substrate 10 in multiple stages by varying the implantation energy so that the high-concentration region 20 has multiple concentration peaks in the Z-axis direction. In S1060, the high-concentration region 20 described with reference to FIGS. 1 to 16 may be formed.

[0225] In S1080, the semiconductor substrate 10 is annealed. In this example, the semiconductor substrate 10 is placed in a heat treatment furnace 150 and the entire semiconductor substrate 10 is annealed at a temperature of approximately 400° C. By separately performing the annealing for forming the high-concentration region 20 in S1050, the annealing temperature can be changed. This allows the N-type dopant implanted in S1070 to be activated at a temperature different from that of the P-type and N-type dopants implanted in S1030 to S1050. For example, if hydrogen is implanted in S1070, the hydrogen in the high-concentration region 20 can be activated in S1080 at a temperature optimal for hydrogen activation.

[0226] By performing S1070 after S1060, it is possible to improve the accuracy of dopant implantation for the high concentration region 20 compared to when S1070 is performed before S1060. For lifetime control, after S1080, there may be a step of implanting impurities to form a lifetime killer into the semiconductor substrate 10, and a third annealing step to recover excessively formed defects.

[0227] In S1090, the collector electrode 24 is formed. In this example, the collector electrode 24 is formed by sputtering so as to contact the entire lower surface 23. This completes the semiconductor device 100A.

[0228] According to the semiconductor device 100A of this embodiment, by using light elements to be implanted deeper from the bottom surface 23 side of the semiconductor substrate 10, it is possible to improve manufacturing efficiency and reduce damage to the semiconductor substrate 10 (silicon substrate). Furthermore, by varying the elements constituting each layer, if contamination or other issues occur, it is easy to analyze which process caused the problem. In particular, in the semiconductor device 100A, the bulk wafer, top surface 21 side, and bottom surface 23 side structures are differentiated based on the properties of the impurities (elements) to create each n-type region, thereby effectively suppressing variations in resistivity. This allows for overall cost reduction.

[0229] As described above, the semiconductor device 100A may not have either the accumulation region 16 or the second high-concentration region 26, or both. In this case, the second element constituting the emitter region 12 and the fifth element constituting the cathode region 82 may be different elements. That is, the emitter region 12, drift region 18, high-concentration region 20, and cathode region 82 provided in a field-stop RC-IGBT may each be formed with a different element as the main dopant. In this case, the fifth element may have a lower mass number than the second element. Furthermore, the length of the emitter region 12 in the depth direction (Z-axis direction) of the semiconductor substrate 10 may be shorter than the length of the cathode region 82. As an example, the second element is arsenic and the fifth element is phosphorus. This allows the above-mentioned effects to be obtained more effectively. The second element, third element, fourth element, fifth element, and sixth element may each contain the same element. For example, the third element and the fifth element may be the same element, and the fourth element and the sixth element may be the same element. Note that it is preferable that the element constituting the main dopant of the bulk wafer is not used in the subsequent ion implantation.

[0230] In one example, the semiconductor device 100A is configured such that the semiconductor layer in contact with the upper surface 21 or the lower surface 23 of the semiconductor substrate 10 is formed by ion implantation of phosphorus or arsenic. Hydrogen ions are implanted between the semiconductor layer on the upper surface 21 side or the semiconductor layer on the lower surface 23 side, closer to the center of the semiconductor substrate 10 than these. The bulk wafer is formed by converting antimony, which is heavier than these, into a donor.

[0231] The order of execution of the processes described with reference to FIGS. 20A to 20D does not necessarily have to be this order. For example, dopant implantation for forming cathode region 82 in S1040 may be performed after formation of top surface structure 116 in S1020. For example, dopant implantation for forming collector region 22 in S1030 may be performed after dopant implantation for forming floating region 84 in S1050. Furthermore, although FIGS. 20A to 20D describe the configuration of an RC-IGBT, the present invention is also applicable to semiconductor devices such as diodes or MOSFETs. In this case, for example, the "source" and "drain" of a transistor such as a MOSFET may also be included within the scope of the terms "emitter" and "collector" in this specification.

[0232] Figure 21 is a diagram showing the characteristics of breakdown voltage variations in drift region 18 and high-concentration region 20. In this example, the main dopant in drift region 18 is antimony, and the main dopant in high-concentration region 20 is hydrogen. The vertical axis of Figure 21 represents electric field strength E (V / cm). The horizontal axis of Figure 21 represents the depth position (μm) in the direction toward bottom surface 23, with the end of drift region 18 on the top surface 21 side as the reference position (position 0).

[0233] The variation in withstand voltage is defined as ΔV / Vc (where Vc is the average value of the withstand voltage, and ΔV is the difference between the maximum and minimum values ​​of the withstand voltage). To simplify the calculation, the doping concentration is set to a constant concentration in each of the drift region 18 and the high-concentration region 20. The average concentration of each region may be used as this constant concentration. By triangular approximation, the voltage can be calculated using Poisson's equation and the equation E = -gradV. The drift region 18 is defined as region I, and the high-concentration region is defined as region II. The variation in withstand voltage is calculated by dividing the two regions.

[0234] (Region I) The gradient of the electric field strength is G1. In this example, gradient G1 is a negative value. Due to variations in the dopant concentration in the drift region 18, gradient G1 increases to a value βG1 multiplied by a coefficient β, or decreases to a value αG1 multiplied by a coefficient α. In this example, coefficient β is greater than 1, and coefficient α is less than 1. In this specification, an increase or decrease in the absolute value of the gradient of the electric field strength is simply referred to as an increase or decrease in the gradient of the electric field strength.

[0235] The maximum electric field strength Ec at position 0 is expressed as y ２ The boundary position in the Z-axis direction between the drift region 18 and the high-concentration region 20 is defined as x ０ Position x ０ Among the electric field intensities at ｃ , the electric field strength when the gradient of the electric field strength decreases to αG1 is y ａ , the electric field strength when the gradient of the electric field strength increases to βG1 is y ｂ The electric field strength y ｃ is the position x ０ The gradient of each electric field intensity E in region I can be expressed by equations (1) to (3). G1 = (y ２ -y ｃ ) / (-x ０ ) ...(1) αG1=(y ２ -y ａ ) / (-x ０ ) ...(2) βG1=(y ２ -y ｂ ) / (-x ０ ) ... (3)

[0236] Eliminating G1 from equations (1) and (2) gives equation (4). ａ = (1-α) y ２ +αy ｃ ...(4) By eliminating G1 from equations (1) and (3), equation (5) is obtained. ｂ = (1 - β) y ２ +βy ｃ ...(5)

[0237] For the voltage in region I, the average value is VIc, the maximum value when it varies is VImax, and the minimum value when it varies is VImin. In FIG. 21, the area of ​​the region indicated by the straight lines of each electric field strength is the voltage, so each voltage can be expressed by equations (6) to (8). VIc = 0.5 × (y ｃ +y ２ ) x ０ ...(6) VImax=0.5×(y ａ +y ２ ) x ０ ...(7) VImin=0.5×(y ｂ +y ２ ) x ０ ...(8)

[0238] As shown in equation (9), y ｃ Yes ２ Let y be χ times the ｃ = χy ２ (0≦χ≦1) (9) Substituting equations (9), (4), and (5) into equations (6) to (8), respectively, y ａ , y ｂ , y ｃ By eliminating the above, we obtain equation (12) from equation (10). VIc = 0.5 × x ０ ×(χ+1)y ２ ...(10) VImax=0.5×x ０ xy ２ (2-α+αχ) ... (11) VImin=0.5×x ０ xy ２ (2-β+βχ) ...(12)

[0239] (Region II) The gradient of the electric field strength is G2. Due to variations in the dopant concentration in the high-concentration region 20, the gradient G2 increases to a value εG2 multiplied by a coefficient ε, or decreases to a value γG2 multiplied by a coefficient γ. In this example, the coefficient ε is greater than 1, and the coefficient γ is less than 1.

[0240] In region II, the line indicating the electric field strength when the dopant concentration of the high concentration region 20 is at the minimum value is at the boundary position x ０, the electric field strength when the dopant concentration in the drift region 18 is at its minimum value is connected to the line at the boundary x between Region I and Region II. ０ In other words, the line with the slope αG1 indicating the electric field strength in region I and the line with the slope γG2 indicating the electric field strength in region II are connected to the boundary X ０ The line with the gradient βG1 indicating the electric field strength in the region I and the line with the gradient εG2 indicating the electric field strength in the region II are connected at the boundary X ０ Connect at.

[0241] (When the voltage in region I is at the maximum value) The voltage in region I becomes the maximum value when the dopant concentration in the drift region 18 varies and becomes the minimum value. １ Position x １ Among the electric field intensities at the boundary x, the average value is ym, and the electric field intensity when the gradient of the electric field intensity decreases to γG2 is yd. ０ The electric field strength at y ａ and the gradient of the electric field intensity in region II is G2, the position x １ The electric field strength at y ｍ１ The gradients of the electric field strength in the region II can be expressed by the following equations (13) and (14): G2 = (y ａ -y ｍ１ ) / (-(x １ -x ０ )) ...(13) γG2=(y ａ -y ｄ ) / (-(x １ -x ０ )) ... (14)

[0242] Eliminate G2 from equations (13) and (14). ａ -y ｃ = y ｍ１ -y ｍ Therefore, equation (15) is obtained. ｄ = y ａ +γ(y ｍ -y ｃ) ... (15)

[0243] (When the voltage in region I is at its minimum value) The voltage in region I becomes its minimum value when the dopant concentration in the drift region 18 varies and reaches its maximum value. １ The average value of the electric field strength at ｍ , the electric field strength when the gradient of the electric field strength increases to εG2 is y ｅ Boundary x ０ The electric field strength at y ｂ and the gradient of the electric field intensity in region II is G2, the position x １ The electric field strength at y ｍ２ The gradients of the electric field strengths in the region II can be expressed by the formulas (16) and (17). G2 = (y ｂ -y ｍ２ ) / (-(x １ -x ０ )) ...(16) εG2=(y ｂ -y ｅ ) / (-(x １ -x ０ )) ... (17)

[0244] Eliminate G2 from equations (16) and (17). ｃ -y ｂ = y ｍ -y ｍ２ Therefore, equation (18) is obtained. ｅ = y ｂ +ε(y ｍ -y ｃ ) ... (18)

[0245] Regarding the voltage in region II, the average value is VIIc, the maximum value when it varies is VIImax, and the minimum value is VIImin. In FIG. 21, the area of ​​the region indicated by the straight lines of each electric field strength is the voltage, so each voltage can be expressed by equations (19) to (21). VIIc = 0.5 × (y ｍ +y ｃ ) (x １ -x ０ )...(19) VIImax=0.5×(y ｄ +y ａ ) (x １ -x０ )...(20) VIImin=0.5×(y ｅ +y ｄ ) (x １ -x ０ ) ... (21)

[0246] As shown in equation (22), y ｍ Yes ｃ Let y be λ times the ｍ = λy ｃ (0≦λ≦1) (22) Using equations (4), (5), (9), and (22), equations (16) to (18) are substituted into equations (19) to (21), respectively, to obtain y ａ , y ｂ , y ｃ , y ｄ , y ｅ , y ｍ By eliminating, we obtain equations (23) to (25). VIIc = 0.5(x １ -x ０ ) x y ２ (λ+1)χ...(23) VIImax=0.5(x １ -x ０ ) x y ２ (2+γ(λ-1)χ) ...(24) VIImin=0.5(x １ -x ０ ) x y ２ (2+ε(λ-1)χ) ...(25)

[0247] (Region I + Region II) In the withstand voltages of Regions I and II, the maximum value is Vmax, the minimum value is Vmin, and the average value is Vc. １ -x ０ = xH, equations (26) to (28) are obtained: Vc = VIc + VIIc = 0.5y ２ [x ０ ×(χ+1)+xH×(λ+1)χ] ...(26) Vmax=VImax+VIImax =0.5y ２ [x ０ ×(2-α+αχ)+xH×(2+γ(λ-1)χ)] ...(27) Vmin=VImin+VIImax =0.5y ２ [x ０×(2-β+βχ)+xH×(2+ε(λ-1)χ)] ...(28)

[0248] The total thickness of the drift region 18 and the high concentration region 20 x １ The ratio of the thickness of the drift region 18 to the thickness of the drift region 18 is defined as ζ. ０ / (x ０ +xH). By using this ζ to eliminate xH from equations (26) to (28), equations (29) to (31) are obtained. Vc = 0.5y ２ x ０ [χ+1+(λ+1)χ(1-ζ) / ζ] ...(29) Vmax=0.5y ２ x ０ [2-α+αχ+{2+γ(λ-1)χ}(1-ζ) / ζ] ...(30) Vmin=0.5y ２ x ０ [2-β+βχ)+{2+ε(λ-1)χ}(1-ζ) / ζ] ...(31)

[0249] From the above, when ΔV=Vmax−Vmin, the breakdown voltage variation ratio ΔV / Vc is expressed by equation (32) which is expressed by the relationship of only coefficients: ΔV / Vc=[(β−α)(1−χ)+(λ−1)χ(γ−ε)(1−ζ) / ζ] / [χ+1+(λ+1)χ(1−ζ) / ζ] (32)

[0250] 22 is a graph showing the relationship between the coefficient ζ and the breakdown voltage variation ratio. This graph shows an example in which the main dopant in the drift region 18 is phosphorus and an example in which it is antimony. According to Poisson's equation, the variation in the doping concentration corresponds to the variation in the gradient of the electric field strength.

[0251] In this example, the variation in the doping concentration of the drift region 18 is set to 30% when the main dopant is phosphorus, and 10% when the main dopant is antimony. This is for the following reasons: - When the additive that serves as the dopant in an MCZ substrate is phosphorus, the deviation in concentration within the ingot is 30% or more of the average value. - When the additive that serves as the dopant in an MCZ substrate is antimony, the deviation in concentration within the ingot is about 10% of the average value. - In other words, the deviation in the dopant concentration within the ingot is smaller when antimony is used than when phosphorus is used.

[0252] When the primary dopant is phosphorus, the coefficients of the drift region 18 described with reference to FIG. 21 and other figures are set to α = 0.7 and β = 1.3. When the primary dopant is antimony, α = 0.9 and β = 1.1. In this example, the primary dopant of the high-concentration region 20 is hydrogen. The coefficients of the high-concentration region 20 are set to χ = 0.5, γ = 0.9, ε = 1.1, and λ = 0.2. These coefficients are not limited to the above values. For example, α may be in the range of 0.5 to 1, β may be in the range of 1 to 1.5, χ may be in the range of 0.1 to 0.9, γ may be in the range of 0.5 to 1, ε may be in the range of 1 to 1.5, and λ may be in the range of 0.1 to 0.9. When the primary dopant of the drift region 18 is phosphorus, α may be in the range of 0.3 to 0.7, and β may be in the range of 1.3 to 3.0. When the primary dopant in drift region 18 is antimony, α may be 0.7 or more and 0.99 or less, and β may be 1.01 or more and 1.3 or less.

[0253] As can be seen from the graph in FIG. 22 , when the primary dopant in the drift region 18 is antimony, the breakdown voltage variation ratio is less than half that in the case of phosphorus. Furthermore, as the coefficient ζ increases, i.e., as the thickness ratio of the drift region 18 decreases, the breakdown voltage variation ratio decreases. This trend is a different effect compared to when the primary dopant is phosphorus. Because antimony has small variations in its chemical concentration in the MCZ ingot, the variations in the antimony chemical concentration in the drift region 18 are also small across multiple semiconductor devices 100. This is thought to be superimposed on the suppression of breakdown voltage variations by the high-concentration region 20. On the other hand, when the primary dopant is phosphorus, the chemical concentration variations in the MCZ ingot are large. The drift region 18 primarily contributes to the breakdown voltage variation, and the influence of this concentration variation is amplified by the high-concentration region 20. It is thought that the increase in the coefficient ζ increases the breakdown voltage variation.

[0254] When the primary dopant of the drift region 18 is antimony, the thickness ratio ζ of the drift region 18 may be 0.1 or more, 0.2 or more, 0.3 or more, or 0.5 or more. When the primary dopant of the drift region 18 is antimony, the thickness ratio ζ of the drift region 18 may be 0.99 or less, 0.95 or less, 0.9 or less, 0.8 or less, or 0.7 or less.

[0255] When the main dopant of the high concentration region 20 is phosphorus, the depth of the high concentration region 20 from the lower surface 23 becomes extremely thin compared to when the main dopant is hydrogen. For example, the thickness of the high concentration region 20 from the lower surface 23 becomes 10% or less of the thickness of the semiconductor substrate 10. In this case, the breakdown voltage variation ratio may be calculated for only region I, and this may be used as the breakdown voltage variation ratio of the semiconductor device 100.

[0256] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0257] 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 that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order.

[0258] The present specification and drawings also disclose aspects described in the following items: (Item 1) A semiconductor device including a semiconductor substrate having an upper surface and a lower surface and including a first conductivity type drift region, wherein a primary dopant in the drift region is antimony, a ratio of a standard deviation of the antimony chemical concentration in a first depth range in a depth direction of the semiconductor substrate to an average concentration of the antimony chemical concentration in the first depth range is 0.2 or less, and a thickness of the first depth range is 80% to 100% of a thickness of the semiconductor substrate. (Item 2) The semiconductor device according to item 1, wherein a ratio of a standard deviation of the antimony chemical concentration in a second depth range in a depth direction of the drift region to an average concentration of the antimony chemical concentration in the second depth range is 0.2 or less, and a thickness of the second depth range is 50% to 100% of a thickness of the drift region. (Item 3) The semiconductor device according to item 1, further comprising: a high-concentration region on the lower surface side of the drift region, the high-concentration region having a doping concentration higher than that of the drift region, wherein a ratio of the thickness of the drift region to a total thickness of the drift region and the high-concentration region in a depth direction is 0.1 or more and 0.9 or less. (Item 4) A semiconductor device comprising a semiconductor substrate having an upper surface and a lower surface and provided with a drift region of a first conductivity type, further comprising: a high-concentration region on the lower surface side of the drift region, the high-concentration region having a doping concentration higher than that of the drift region, the main dopant of the drift region is antimony, and the ratio of the thickness of the drift region to a total thickness of the drift region and the high-concentration region in a depth direction is 0.1 or more and 0.99 or less.(Item 5) A method for manufacturing a semiconductor device, comprising: preparing a semiconductor substrate of a first conductivity type having an upper surface and a lower surface and containing a volatile first element as a bulk donor; ion-implanting a first light element having a lower mass number than the first element from the lower surface side to form a field stop region of the first conductivity type; and ion-implanting a second light element having a lower mass number than the first element from the lower surface side to form a cathode region of the first conductivity type in at least a part of the lower surface of the semiconductor substrate, wherein the first element, the first light element, and the second light element are different elements, and the mass number of the first light element is lower than that of the second light element. (Item 6) A method for manufacturing a semiconductor device according to Item 5, comprising the step of ion-implanting a third light element having a mass number lower than that of the first element from the top surface side to form an emitter region of a first conductivity type in at least a part of the top surface of the half-body substrate, wherein the third light element is an element different from the first element, the first light element, and the second light element, and the first light element and the second light element have mass numbers lower than that of the third light element.

[0259] 10...Semiconductor substrate, 11...Well region, 12...Emitter region, 14...Base region, 15...Contact region, 16...Accumulation region, 18...Drift region, 20...High concentration region, 21...Upper surface, 22...Collector region, 23...Lower surface, 24...Collector electrode, 26...Second high concentration region, 29...Straight portion, 30...Dummy trench portion, 31...Tip portion, 32...Dummy 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, 68-1, 68-2...Mask, 70...Transistor portion, 80...Diode portion, 81...Extension region, 82...Cathode region, 84...Floating region , 86...particle, 87...second cathode region, 88...defect, 89...electric field relaxation region, 90...edge termination structure portion, 100...semiconductor device, 116...upper surface side structure, 118...lower surface side structure, 130...periphery gate wiring, 131...active side gate wiring, 150...heat treatment furnace, 160...active portion, 162...edge, 164...gate pad, 191...first depth range, 192...second Depth range, 202... hydrogen chemical concentration peak, 204... hydrogen chemical concentration valley, 212... carrier concentration peak, 214... carrier concentration valley, 222... hydrogen donor concentration peak, 224... hydrogen donor concentration valley, 231... first portion, 232... second portion, 233... third portion, 241... lower region, 242... upper region, 300, 302, 304, 306, 310, 312, 314, 316... concentration distribution

Claims

1. A semiconductor device comprising a semiconductor substrate having an upper surface and a lower surface, bulk donors distributed between the upper surface and the lower surface, and a drift region of a first conductivity type, a high concentration region of a first conductivity type disposed between the drift region and the lower surface of the semiconductor substrate, the high concentration region including hydrogen donors and having a carrier concentration higher than a bulk donor concentration; The high concentration region has a hydrogen donor concentration, which is calculated by subtracting the bulk donor concentration from the carrier concentration, of 7×10 １３ / cm ３ That's it, 1.5 x 10 １４ / cm ３ a first portion that is: The semiconductor device, wherein the length of the first portion in the depth direction of the semiconductor substrate is 50% or more of the length of the high concentration region.

2. the high concentration region has a plurality of hydrogen donor concentration peaks in the depth direction, the plurality of hydrogen donor concentration peaks includes a shallowest donor concentration peak closest to the bottom surface of the semiconductor substrate and a deepest donor concentration peak closest to the top surface of the semiconductor substrate; the high concentration region has a second portion that is a region from the shallowest donor concentration peak to the deepest donor concentration peak; In a depth direction of the semiconductor substrate, the length of the first portion is 50% or more of the length of the second portion. The semiconductor device according to claim 1 .

3. the high concentration region has a plurality of hydrogen donor concentration peaks in the depth direction, the plurality of hydrogen donor concentration peaks includes a deepest donor concentration peak closest to the top surface of the semiconductor substrate; The high concentration region has a hydrogen donor concentration of 7×10 in a region from the lower surface of the semiconductor substrate to the deepest donor concentration peak. １３ / cm ３ a third portion continuous with the region less than The length of the third portion in the depth direction is 15 μm or less. The semiconductor device according to claim 1 .

4. the high concentration region has a plurality of hydrogen donor concentration peaks in the depth direction, the plurality of hydrogen donor concentration peaks includes a deepest donor concentration peak closest to the top surface of the semiconductor substrate; The high concentration region has a hydrogen donor concentration of 7×10 in a region from the lower surface of the semiconductor substrate to the deepest donor concentration peak. １３ / cm ３ a third portion continuous with the region less than In the depth direction of the semiconductor substrate, the length of the third portion is 20% or less of the length of the high concentration region. The semiconductor device according to claim 1 .

5. the high concentration region has a plurality of hydrogen donor concentration peaks in the depth direction, the plurality of hydrogen donor concentration peaks includes a shallowest donor concentration peak closest to the bottom surface of the semiconductor substrate and a deepest donor concentration peak closest to the top surface of the semiconductor substrate; In the high concentration region, the minimum value of the hydrogen donor concentration from the shallowest donor concentration peak to the deepest donor concentration peak is 7×10 １３ / cm ３ That's all. The semiconductor device according to claim 1 .

6. the high concentration region has a plurality of hydrogen chemical concentration peaks in the depth direction, In each hydrogen chemical concentration peak, the length in the depth direction of a portion where the hydrogen chemical concentration is 10% or more of the maximum value is defined as a hydrogen peak width, and the sum of the hydrogen peak widths of the multiple hydrogen chemical concentration peaks is 30% or more of the length in the depth direction of the high concentration region. The semiconductor device according to claim 1 .

7. The sum of the hydrogen peak widths is 50% or more of the length of the high concentration region. The semiconductor device according to claim 6.

8. The plurality of hydrogen chemical concentration peaks include a hydrogen chemical concentration peak having a concentration that is 0.8 times or more and 1.2 times or less than a concentration of at least one hydrogen chemical concentration peak disposed adjacent to the concentration peak in the depth direction, Three or more of the same concentration peaks are arranged consecutively in the depth direction. The semiconductor device according to claim 6.

9. the high concentration region has an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction, In the upper region, three or more of the same concentration peaks are arranged consecutively in the depth direction. The semiconductor device according to claim 8.

10. The sum of the hydrogen peak widths in the upper region is 30% or more of the length of the upper region in the depth direction. The semiconductor device according to claim 9.

11. the hydrogen donors in the high concentration region include interstitial donors, The concentration of the interstitial donor is 30% or more of the concentration of the hydrogen donor. The semiconductor device according to claim 1 .

12. the high concentration region has, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks, the plurality of hydrogen donor concentration peaks includes a deepest donor concentration peak closest to the top surface of the semiconductor substrate and a second deepest donor concentration peak second closest to the top surface of the semiconductor substrate; the one or more hydrogen donor concentration valleys include a deepest donor concentration valley closest to the top surface of the semiconductor substrate; a value obtained by dividing the hydrogen donor concentration at the second deep donor concentration peak by the hydrogen donor concentration at the deepest donor concentration valley is 1.1 or more and 2.0 or less. The semiconductor device according to claim 1 .

13. the high concentration region has a plurality of hydrogen chemical concentration peaks in the depth direction, the plurality of hydrogen chemical concentration peaks includes a third hydrogen concentration peak that is third closest to the bottom surface of the semiconductor substrate; the high concentration region includes a lower region from the lower surface of the semiconductor substrate to the third hydrogen concentration peak, and an upper region located on the upper surface side of the semiconductor substrate relative to the third hydrogen concentration peak, the lower region has, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks; the plurality of hydrogen donor concentration peaks in the lower region include a lower deepest donor concentration peak furthest from the lower surface of the semiconductor substrate; the one or more hydrogen donor concentration valleys in the lower region include a lower deepest donor concentration valley furthest from the lower surface of the semiconductor substrate; The hydrogen donor concentration N １ is the hydrogen donor concentration N ２ The value a obtained by dividing by is 1.2 or more and 4.0 or less. The semiconductor device according to claim 1 .

14. the upper region has, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks; the plurality of hydrogen donor concentration peaks in the upper region include a deepest donor concentration peak closest to the top surface of the semiconductor substrate and a second deepest donor concentration peak second closest to the top surface of the semiconductor substrate; the one or more hydrogen donor concentration valleys in the upper region include a deepest donor concentration valley closest to the top surface of the semiconductor substrate; The hydrogen donor concentration n at the second deep donor concentration peak １ The hydrogen donor concentration n at the deepest donor concentration valley ２ The value a / b obtained by dividing the value a by the value b obtained by dividing the value a by the value b is greater than 0.

5. The semiconductor device according to claim 13.

15. The hydrogen donor concentration n at the second deep donor concentration peak １ is the hydrogen donor concentration N at the bottom deepest donor concentration peak １ is less than 0.5 times The semiconductor device according to claim 14.

16. the high concentration region has a lower region on the lower surface side of the semiconductor substrate relative to a center of the high concentration region in the depth direction, and an upper region on the upper surface side of the semiconductor substrate relative to the center of the high concentration region, Each of the lower region and the upper region has, in the depth direction, a plurality of hydrogen donor concentration peaks and one or more hydrogen donor concentration valleys disposed between two hydrogen donor concentration peaks, The hydrogen donor concentration in at least one of the hydrogen donor concentration valleys in the upper region is higher than the hydrogen donor concentration in at least one of the hydrogen donor concentration valleys in the lower region. The semiconductor device according to claim 1 .

17. the high concentration region has an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction, the upper region has a plurality of hydrogen chemical concentration peaks in the depth direction; Of the plurality of hydrogen chemical concentration peaks in the upper region, 5×10 １５ / cm ３ the sum of the full width at half maximum of one or more hydrogen chemical concentration peaks having a hydrogen chemical concentration of at least 20% to 90% of the length of the upper region in the depth direction. The semiconductor device according to claim 1 .

18. the high concentration region has an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction, the upper region has a plurality of hydrogen donor concentration peaks in the depth direction; Among the plurality of hydrogen donor concentration peaks in the upper region, 7×10 １３ / cm ３ the sum of full widths at half maximum of one or more hydrogen donor concentration peaks having a hydrogen donor concentration of 30% or more of the length of the upper region in the depth direction. The semiconductor device according to claim 1 .

19. the high concentration region has an upper region that is a portion that is 20 μm or more away from the lower surface of the semiconductor substrate in the depth direction, In the upper region, the integral concentration of the hydrogen donor in the depth direction is 8×10 １０ / cm ２ That's it, 2 x 10 １１ / cm ２ is less than or equal to The semiconductor device according to claim 1 .

20. the high concentration region has an upper region provided in at least a portion of a range in which a distance from the lower surface of the semiconductor substrate in the depth direction is 25% or more and 50% or less of a thickness of the semiconductor substrate, the upper region has a plurality of hydrogen chemical concentration peaks in the depth direction; Of the plurality of hydrogen chemical concentration peaks in the upper region, 5×10 １５ / cm ３ the sum of the full width at half maximum of one or more hydrogen chemical concentration peaks having a hydrogen chemical concentration of at least 20% to 90% of the length of the upper region in the depth direction. The semiconductor device according to claim 1 .

21. the high concentration region has an upper region provided in at least a portion of a range in which a distance from the lower surface of the semiconductor substrate in the depth direction is 25% or more and 50% or less of a thickness of the semiconductor substrate, the upper region has a plurality of hydrogen donor concentration peaks in the depth direction; Among the plurality of hydrogen donor concentration peaks in the upper region, 7×10 １３ / cm ３ the sum of full widths at half maximum of one or more hydrogen donor concentration peaks having a hydrogen donor concentration of 30% or more of the length of the upper region in the depth direction. The semiconductor device according to claim 1 .

22. the high concentration region has an upper region provided in at least a portion of a range in which a distance from the lower surface of the semiconductor substrate in the depth direction is 25% or more and 50% or less of a thickness of the semiconductor substrate, In the upper region, the integral concentration of the hydrogen donor in the depth direction is 8×10 １０ / cm ２ That's it, 2 x 10 １１ / cm ２ is less than or equal to The semiconductor device according to claim 1 .

23. The upper region is provided over an entire range of 25% to 50% of the thickness of the semiconductor substrate. The semiconductor device according to claim 20.

24. The carbon concentration of the semiconductor substrate is 1×10 １３ / cm ３ That's it, 5 x 10 １５ / cm ３ is less than or equal to The semiconductor device according to claim 1 .

25. the primary dopant in the drift region is antimony; a ratio of a standard deviation of antimony chemical concentration in a first depth range in a depth direction of the semiconductor substrate to an average concentration of antimony chemical concentration in the first depth range is 0.2 or less; The thickness of the first depth range is 50% or more and 100% or less of the thickness of the semiconductor substrate. The semiconductor device according to claim 1 .

26. A semiconductor device including a semiconductor substrate having an upper surface and a lower surface and having a first conductivity type drift region provided therein, the primary dopant in the drift region is antimony; a ratio of a standard deviation of antimony chemical concentration in a first depth range in a depth direction of the semiconductor substrate to an average concentration of antimony chemical concentration in the first depth range is 0.2 or less; The thickness of the first depth range is 50% or more and 100% or less of the thickness of the semiconductor substrate. Semiconductor device.

27. a ratio of a standard deviation of antimony chemical concentration in a second depth range in a depth direction of the drift region to an average concentration of antimony chemical concentration in the second depth range is 0.2 or less; The thickness of the second depth range is 50% or more and 100% or less of the thickness of the drift region. The semiconductor device according to claim 26.

28. a high concentration region having a doping concentration higher than that of the drift region is provided on the lower surface side of the drift region; The ratio of the thickness of the drift region to the total thickness of the drift region and the high concentration region in the depth direction is 0.1 or more and 0.99 or less. The semiconductor device according to claim 26.

29. A semiconductor device including a semiconductor substrate having an upper surface and a lower surface and having a first conductivity type drift region provided therein, a high concentration region having a doping concentration higher than that of the drift region is provided on the lower surface side of the drift region; the primary dopant in the drift region is antimony; The ratio of the thickness of the drift region to the total thickness of the drift region and the high concentration region in the depth direction is 0.1 or more and 0.99 or less. Semiconductor device.

30. In the depth direction of the semiconductor substrate, the length of the first portion is 70% or more of the length of the high concentration region. The semiconductor device according to claim 1 .

31. the high concentration region has a plurality of hydrogen chemical concentration peaks in the depth direction, The plurality of hydrogen chemical concentration peaks include a hydrogen chemical concentration peak having a concentration that is 0.8 times or more and 1.2 times or less than a concentration of at least one hydrogen chemical concentration peak disposed adjacent to the concentration peak in the depth direction, Three or more of the same concentration peaks are arranged consecutively in the depth direction. The semiconductor device according to claim 1 .

32. The hydrogen donor concentration N １ is the hydrogen donor concentration N ２ The value a divided by is 2.5 or more and 4.0 or less. The semiconductor device according to claim 13.

33. The hydrogen donor concentration N １ is the hydrogen donor concentration N ２ The value a obtained by dividing by is 1.2 or more and 3.0 or less. The semiconductor device according to claim 13.

34. The peak concentration of the third hydrogen concentration peak is greater than the peak concentration of at least one of the hydrogen chemical concentration peaks provided in the upper region. The semiconductor device according to claim 13.

35. The hydrogen donor concentration n at the second deep donor concentration peak １ The hydrogen donor concentration n at the deepest donor concentration valley ２ The value a / b obtained by dividing the value a by the value b obtained by dividing the value a by is greater than 1. The semiconductor device according to claim 14.

36. The antimony is distributed from the top surface to the bottom surface of the semiconductor substrate.

30. The semiconductor device according to claim 26 or 29.

37. The ratio of the thickness of the drift region to the total thickness of the drift region and the high concentration region in the depth direction is 0.1 or more and 0.8 or less.

30. The semiconductor device according to claim 28 or 29.

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