Semiconductor device and method of manufacturing the same

Abstract

Provided is a semiconductor device including a semiconductor substrate having an upper surface and a lower surface. The hydrogen chemical concentration distribution in the depth direction of the semiconductor substrate has a first hydrogen concentration peak and a second hydrogen concentration peak located on the lower surface side of the semiconductor substrate relative to the first hydrogen concentration peak. The intermediate donor concentration between the first hydrogen concentration peak and the second hydrogen concentration peak is different from both the upper surface side donor concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate and the lower surface side donor concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate. The intermediate donor concentration can be higher than both the upper surface side donor concentration and the lower surface side donor concentration.

Description

Technical Field

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

[0002] Conventionally, the following technique has been known: By injecting hydrogen into a predetermined depth of a semiconductor substrate and diffusing it, lattice defects in the injection depth and diffusion region are combined with hydrogen and donorized, and the doping concentration can be increased (for example, refer to Patent Documents 1 and 2).

[0003] Patent Document 1: Japanese Patent No. 5374883

[0004] Patent Document 2: WO2017 / 47285 Summary of the Invention

[0005] Technical Problem

[0006] It is desired to easily adjust a wide range of doping concentrations in the depth direction of a semiconductor substrate.

[0007] Technical Solution

[0008] To solve the above problems, in a first aspect of the present invention, there is provided a semiconductor device including a semiconductor substrate having an upper surface and a lower surface. The hydrogen chemical concentration distribution in the depth direction of the semiconductor substrate may have: a first hydrogen concentration peak; and a second hydrogen concentration peak disposed at a position closer to the lower surface side of the semiconductor substrate than the first hydrogen concentration peak. The intermediate donor concentration between the first hydrogen concentration peak and the second hydrogen concentration peak may be different from both the upper surface side donor concentration, which is the donor concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate, and the lower surface side donor concentration, which is the donor concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

[0009] The intermediate donor concentration may be higher than both the upper surface side donor concentration and the lower surface side donor concentration.

[0010] The intermediate hydrogen concentration between the first hydrogen concentration peak and the second hydrogen concentration peak may be higher than both the upper surface side hydrogen concentration, which is the hydrogen concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate, and the lower surface side hydrogen concentration, which is the hydrogen concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

[0011] The intermediate donor concentration may be 1×10 13 / cm 3 or more and 1×10 15 / cm 3 or less.

[0012] The intermediate donor concentration can be 1.5 times or more with respect to each of the upper surface side donor concentration and the lower surface side donor concentration.

[0013] The hydrogen chemical concentration distribution can have a first upper surface side tail in which the hydrogen concentration decreases from the first hydrogen concentration peak toward the upper surface side. The hydrogen chemical concentration distribution can have a first lower surface side tail in which the hydrogen concentration decreases more gently from the first hydrogen concentration peak toward the lower surface side than the first upper surface side tail. The hydrogen chemical concentration distribution can have a second lower surface side tail in which the hydrogen concentration decreases from the second hydrogen concentration peak toward the lower surface side. The hydrogen chemical concentration distribution can have a second upper surface side tail in which the hydrogen concentration decreases more gently from the second hydrogen concentration peak toward the upper surface side than the second lower surface side tail.

[0014] The first hydrogen concentration peak can be higher than the second hydrogen concentration peak. The lower surface side donor concentration can be higher than the upper surface side donor concentration.

[0015] The second hydrogen concentration peak can be higher than the first hydrogen concentration peak. The upper surface side donor concentration can be higher than the lower surface side donor concentration.

[0016] The semiconductor substrate can have a drift region of a first conductivity type. The semiconductor substrate can have a trench portion provided on the upper surface of the semiconductor substrate. The semiconductor substrate can have a buffer region of a first conductivity type provided between the drift region and the lower surface of the semiconductor substrate and having a concentration higher than that of the drift region. The first hydrogen concentration peak and the second hydrogen concentration peak can be arranged in the depth direction between the lower end of the trench portion and the upper end of the buffer region. The intermediate donor concentration between the first hydrogen concentration peak and the second hydrogen concentration peak can be lower than both the upper surface side donor concentration and the lower surface side donor concentration, where the upper surface side donor concentration is the donor concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate, and the lower surface side donor concentration is the donor concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

[0017] Both the first hydrogen concentration peak and the second hydrogen concentration peak can be arranged between the center in the depth direction of the semiconductor substrate and the upper surface.

[0018] The intermediate hydrogen concentration can be 10 times or more the intermediate donor concentration.

[0019] Both the lower surface side donor concentration and the upper surface side donor concentration can be higher than the bulk donor concentration of the semiconductor substrate.

[0020] The donor concentration distribution in the depth direction of the semiconductor substrate can have flat portions both between the first hydrogen concentration peak and the upper surface of the semiconductor substrate and between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

[0021] The donor concentration distribution in the depth direction of the semiconductor substrate can have a flat portion between the first hydrogen concentration peak and the second hydrogen concentration peak.

[0022] The distance in the depth direction between the first hydrogen concentration peak and the second hydrogen concentration peak can be 1 / 2 or less of the thickness in the depth direction of the semiconductor substrate.

[0023] In the second aspect of the present invention, a method for manufacturing a semiconductor device is provided. The manufacturing method may include a hydrogen injection step of injecting hydrogen ions from one of the upper surface and the lower surface of the semiconductor substrate to a first depth position, and injecting hydrogen ions from the other of the upper surface and the lower surface of the semiconductor substrate to a second depth position different from the first depth position. The manufacturing method may include a heat treatment step of performing a heat treatment on the semiconductor substrate.

[0024] The second depth position may be disposed between the first depth position and one of the surfaces.

[0025] The second depth position may be disposed between the first depth position and the other surface. The semiconductor substrate may have a drift region of a first conductivity type. The semiconductor substrate may have a trench portion provided on the upper surface of the semiconductor substrate. The semiconductor substrate may have a buffer region of a first conductivity type provided between the drift region and the lower surface of the semiconductor substrate and having a concentration higher than that of the drift region. The first depth position and the second depth position may be disposed in the depth direction between the lower end of the trench portion and the upper end of the buffer region.

[0026] The manufacturing method may include a laser annealing step of performing laser annealing on at least one of the upper surface and the lower surface of the semiconductor substrate. The hydrogen injection step may be performed after the laser annealing step.

[0027] It should be noted that the above summary of the invention does not list all the essential features of the present invention. In addition, sub-combinations of these feature groups can also form inventions. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0029] Figure 2 shows Figure 1 the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the line A-A of

[0030] Figure 3 is a diagram for explaining the flat portion 150 in the concentration distribution.

[0031] Figure 4 shows Figure 1 another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the line A-A of

[0032] Figure 5 shows Figure 1Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line.

[0033] Figure 6 Shows Figure 1 Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line.

[0034] Figure 7 Shows Figure 1 Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line.

[0035] Figure 8 Shows Figure 1 Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line.

[0036] Figure 9 Is a top view showing an example of the semiconductor device 100.

[0037] Figure 10 Is Figure 9 An enlarged view of the region C in

[0038] Figure 11 Is a view showing Figure 10 An example of the b-b cross section in

[0039] Figure 12 Is a view showing another example of passing through the region 106-1 and passing through the region 106-2.

[0040] Figure 13 Is a view showing Figure 12 An example of the doping concentration distribution at the D-D line in

[0041] Figure 14 Is a view showing Figure 13 An example of the hydrogen chemical concentration distribution and the donor concentration distribution in the region near the depth positions Z1 and Z2 shown in

[0042] Figure 15 Is a view showing Figures 1 to 14 An example of the manufacturing method of the semiconductor device 100 described in

[0043] Symbol description

[0044] 10: Semiconductor substrate, 11: Well region, 12: Emitter region, 14: Base region, 15: Contact region, 16: Accumulation region, 18: Drift region, 20: Buffer region, 21: Upper surface, 22: Collector region, 23: Lower surface, 24: Collector electrode, 25: Peak, 29: Straight portion, 30: dummy trench portion, 31: Front end portion, 32: dummy insulating film, 34: dummy conductive portion, 38: Interlayer insulating film, 39: Straight portion, 40: Gate trench portion, 41: Front end portion, 42: Gate insulating film, 44: Gate conductive portion, 52: Emitter electrode, 54: Contact hole, 60, 61: Step surface portion, 70: Transistor portion, 80: Diode portion, 81: Extension region, 82: Cathode region, 90: Edge termination structure portion, 100: Semiconductor device, 101: First hydrogen concentration peak, 102: Second hydrogen concentration peak, 103: Intermediate hydrogen distribution, 104: Upper surface side hydrogen distribution, 105: Lower surface side hydrogen distribution, 106: Passing region, 111: First donor concentration peak, 112: Second donor concentration peak, 113: Intermediate donor distribution, 114: Upper surface side donor distribution, 115: Lower surface side donor distribution, 130: Peripheral gate wiring, 131: Active side gate wiring, 150: Flat portion, 160: Active portion, 162: End edge, 164: Gate pad Detailed implementation mode

[0045] Hereinafter, the present invention will be described by way of embodiments of the invention. However, the following embodiments do not limit the invention described in the claims. In addition, all combinations of the features described in the embodiments are not necessarily essential for the solution of the invention.

[0046] In this specification, one side in the direction parallel to the depth direction of the semiconductor substrate is referred to as "upper", and the other side is referred to as "lower". One of the two main surfaces of the substrate, layer or other component 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 gravitational direction or the direction when the semiconductor device is installed.

[0047] In this specification, orthogonal coordinate axes of the X-axis, Y-axis and Z-axis are sometimes used to describe technical matters. The orthogonal coordinate axes only determine the relative positions of the components and do not limit a specific direction. For example, the Z-axis is not limited to representing the height direction with respect to the ground. It should be noted that the +Z-axis direction and the -Z-axis direction are opposite directions to each other. When the positive and negative are not described and only the Z-axis direction is described, it means the direction parallel to the +Z-axis and the -Z-axis.

[0048] In this specification, orthogonal axes parallel to the upper and lower surfaces of the semiconductor substrate are defined as the X-axis and the Y-axis. In addition, an axis perpendicular to the upper and lower surfaces of the semiconductor substrate is defined as the Z-axis. In this specification, the direction of the Z-axis is sometimes referred to as the depth direction. In addition, in this specification, the direction parallel to the upper and lower surfaces of the semiconductor substrate including the X-axis and the Y-axis is sometimes referred to as the horizontal direction.

[0049] In this specification, when referred to as "the same" or "equal", it may also include cases with errors caused by manufacturing deviations or the like. The error is, for example, within 10%.

[0050] In this specification, the conductivity type of the doped region doped with impurities is described as P-type or N-type. In this specification, impurities sometimes specifically refer to either N-type donors or P-type acceptors, and are sometimes referred to as dopants. In this specification, doping refers to introducing a donor or an acceptor into the semiconductor substrate to make it a semiconductor with an N-type conductivity type or a P-type conductivity type.

[0051] In this specification, the doping concentration refers to the concentration of donors or acceptors in the thermal equilibrium state. In this specification, the net doping concentration refers to the concentration of donors as positive ions and the concentration of acceptors as negative ions, and is the actual concentration obtained by adding them together including the polarity of the charges. As an example, if the donor concentration is set as N D , and the acceptor concentration is set as N A , then the actual net doping concentration at any position is N D - N A . In this specification, the net doping concentration is sometimes only referred to as the doping concentration.

[0052] Donors have the function of supplying electrons to the semiconductor. Acceptors have the function of accepting electrons from the semiconductor. Donors and acceptors are not limited to the impurities themselves. For example, VOH defects formed by the combination of vacancies (V), oxygen (O), and hydrogen (H) present in the semiconductor function as electron-supplying donors. In this specification, VOH defects are sometimes referred to as hydrogen donors.

[0053] In this specification, when described as P+ type or N+ type, it means that the doping concentration is higher than that of P-type or N-type. When described as P- type or N- type, it means that the doping concentration is lower than that of P-type or N-type. In addition, in this specification, when described as P++ type or N++ type, it means that the doping concentration is higher than that of P+ type or N+ type.

[0054] In this specification, the chemical concentration refers to the atomic density of impurities measured regardless of the state of electroactivation. The chemical concentration can be measured, for example, by secondary ion mass spectrometry (SIMS). The above-mentioned net doping concentration can be measured by voltage-capacitance measurement (CV method). In addition, the carrier concentration measured by the spreading resistance measurement (SR method) can be used as the net doping concentration. The carrier concentration measured by the CV method or the SR method can be regarded as a value under the thermal equilibrium state. In addition, in the N-type region, the donor concentration is sufficiently greater than the acceptor concentration. Therefore, the carrier concentration in this region can be used as the donor concentration. Similarly, in the P-type region, the carrier concentration in this region can be used as the acceptor concentration. In this specification, sometimes the doping concentration in the N-type region is referred to as the donor concentration, and sometimes the doping concentration in the P-type region is referred to as the acceptor concentration.

[0055] In addition, when the concentration distribution of donors, acceptors, or net doping has a peak, the peak value can be used as the concentration of donors, acceptors, or net doping in this region. When the concentration of donors, acceptors, or net doping is substantially uniform, etc., the average value of the concentration of donors, acceptors, or net doping in this region can be used as the concentration of donors, acceptors, or net doping.

[0056] The carrier concentration measured by the SR method can be lower than the concentration of donors or acceptors. In the range where the current flows when measuring the spreading resistance, sometimes the carrier mobility of the semiconductor substrate is lower than the value in the crystalline state. The decrease in carrier mobility is caused by the scattering of carriers due to the disorder (disorder) of the crystal structure caused by lattice defects, etc.

[0057] The concentration of donors or acceptors calculated based on the carrier concentration measured by the CV method or the SR method can be lower than the chemical concentration of the element representing the donor or acceptor. As an example, the donor concentration of phosphorus or arsenic that becomes a donor in a silicon semiconductor or the acceptor concentration of boron that becomes an acceptor is about 99% of their chemical concentration. On the other hand, the donor concentration of hydrogen that becomes a donor in a silicon semiconductor is on the order of 0.1% to 10% of the chemical concentration of hydrogen.

[0058] Figure 1 FIG. is a cross-sectional view showing an example of the semiconductor device 100. The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 is a substrate formed of a semiconductor material. As an example, the semiconductor substrate 10 is a silicon substrate.

[0059] In the semiconductor substrate 10, at least one of transistor elements such as insulated gate bipolar transistors (IGBTs) and diode elements such as freewheeling diodes (FWDs) is formed. In Figure 1In the figure, each electrode of the transistor element and the diode element, and each region provided inside the semiconductor substrate 10 are omitted. A configuration example of the transistor element and the diode element will be described later.

[0060] In the case of the semiconductor substrate 10 of this example, N-type bulk donors are distributed throughout. The bulk donors are donors formed by dopants contained substantially uniformly in the ingot that is the raw material for the semiconductor substrate 10. The bulk donors of this example are elements other than hydrogen. The dopants of the bulk donors are, for example, phosphorus, antimony, arsenic, selenium, or sulfur, but are not limited thereto. The bulk donors of this example are phosphorus. The bulk donors are also contained in the P-type regions. The semiconductor substrate 10 may be a wafer cut from a semiconductor ingot, or a chip obtained by singulating the wafer. The semiconductor ingot can be manufactured using any one of the Czochralski method (CZ method), magnetic field applied Czochralski method (MCZ method), and floating zone melting method (FZ method). The ingot in this example is manufactured using the MCZ method. The bulk donor concentration can be the chemical concentration of the bulk donors distributed throughout the semiconductor substrate 10, or a value between 90% and 100% of this chemical concentration.

[0061] The semiconductor substrate 10 has an upper surface 21 and a lower surface 23. The upper surface 21 and the lower surface 23 are the two main surfaces of the semiconductor substrate 10. In this specification, the orthogonal axes in the plane parallel to the upper surface 21 and the lower surface 23 are set as the X-axis and the Y-axis, and the axis perpendicular to the upper surface 21 and the lower surface 23 is set as the Z-axis.

[0062] In the semiconductor substrate 10, hydrogen ions are implanted from the lower surface 23 to a depth position Z1. Further, in the semiconductor substrate 10, hydrogen ions are implanted from the upper surface 21 to a depth position Z2. Implanting hydrogen ions to a predetermined depth position means accelerating the hydrogen ions with an acceleration energy corresponding to that depth position and implanting them. The hydrogen ions are not only distributed at that depth position, but also in the vicinity of that depth position. Further, they can also be distributed in the passage region 106 between the implantation surface and that depth position.

[0063] The hydrogen chemical concentration distribution in the depth direction of the semiconductor substrate 10 has a first hydrogen concentration peak 101 at the depth position Z1 and a second hydrogen concentration peak 102 at the depth position Z2. In Figure 1 the figure, the hydrogen concentration peaks are schematically shown by cross marks. In Figure 1 the figure, the depth position Z1 is arranged between the upper surface 21 and the depth position Z2, but the depth position Z1 can also be arranged between the lower surface 23 and the depth position Z2.

[0064] In this specification, the region through which the implanted hydrogen ions pass is sometimes referred to as the passing region. In the passing region 106-1 between the lower surface 23 and the depth position Z1 and the passing region 106-2 between the upper surface 21 and the depth position Z2, lattice defects mainly composed of vacancies such as single-atom vacancies (V) and double-atom vacancies (VV) are formed by passing hydrogen. The atoms adjacent to the vacancies have dangling bonds. Although lattice defects also include interstitial atoms and / or dislocations, etc., and in a broad sense can also include donors and / or acceptors, in this specification, the lattice defects mainly composed of vacancies are sometimes referred to as vacancy-type lattice defects, vacancy-type defects, or simply lattice defects. In addition, by implanting hydrogen ions into the semiconductor substrate 10, a large number of lattice defects are formed, and thus the crystallinity of the semiconductor substrate 10 may be severely disordered. In this specification, this disorder of crystallinity is sometimes referred to as disorder.

[0065] In addition, oxygen is contained throughout the semiconductor substrate 10. This oxygen is introduced intentionally or unintentionally during the production of the semiconductor ingot. Inside the semiconductor substrate 10, hydrogen (H), vacancies (V), and oxygen (O) combine to form VOH defects. In addition, by performing heat treatment on the semiconductor substrate 10 to allow hydrogen to diffuse, the formation of VOH defects is promoted. VOH defects function as electron-supplying donors. In this specification, VOH defects are sometimes simply referred to as hydrogen donors. In the semiconductor substrate 10 of this example, hydrogen donors are formed in the passing region 106 of hydrogen ions. The doping concentration of the hydrogen donors is lower than the chemical concentration of hydrogen. If the ratio of the doping concentration of the hydrogen donors to the chemical concentration of hydrogen is defined as the activation rate, the activation rate can be a value of 0.1% to 30%. In this example, the activation rate is 1% to 5%.

[0066] By forming hydrogen donors in the passing region 106 of the semiconductor substrate 10, the donor concentration in the passing region 106 of the semiconductor substrate 10 can be made higher than the bulk donor concentration. Generally, a semiconductor substrate 10 having a predetermined bulk donor concentration corresponding to the characteristics of the elements to be formed on the semiconductor substrate 10, particularly the rated voltage or breakdown voltage, must be prepared. Regarding this, according to Figure 1 the semiconductor device 100 shown, by controlling the dose and implantation depth of hydrogen ions, the donor concentration in a predetermined region of the semiconductor substrate 10 can be adjusted. Therefore, a semiconductor device 100 can be manufactured using a semiconductor substrate having a bulk donor concentration not corresponding to the characteristics of the elements, etc. Although the deviation of the bulk donor concentration during the production of the semiconductor substrate 10 is large, the dose of hydrogen ions can be controlled with high precision. Therefore, the concentration of lattice defects generated by implanting hydrogen ions can also be controlled with high precision, and the donor concentration in the passing region 106 can be controlled with high precision.

[0067] In addition, in the semiconductor device 100, hydrogen ions are implanted from both the upper surface 21 and the lower surface 23. Therefore, a wide range of via regions 106 can be easily formed. In Figure 1 the example of

[0068] Figure 2 shown Figure 1 in the position shown by the A-A line of Figure 2 the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction are shown. Figure 2 The horizontal axis of Figure 2 shows the depth position measured from the lower surface 23, and the vertical axis shows the hydrogen chemical concentration and the donor concentration per unit volume on a logarithmic axis. Figure 2 The donor concentration in Figure 2 is measured by, for example, the CV method or the SR method.

[0069] The hydrogen chemical concentration distribution has a first hydrogen concentration peak 101 and a second hydrogen concentration peak 102. The second hydrogen concentration peak 102 is arranged at a position closer to the lower surface 23 side of the semiconductor substrate 10 than the first hydrogen concentration peak 101. That is, the second hydrogen concentration peak 102 is arranged between the first hydrogen concentration peak 101 and the lower surface 23.

[0070] The position of the first hydrogen concentration peak 101 in the depth direction is set as Z1, and the position of the second hydrogen concentration peak 102 in the depth direction is set as Z2. The position of the concentration peak is the position where the concentration becomes the maximum value.

[0071] The hydrogen chemical concentration distribution has a first upper surface side tail S1a, a first lower surface side tail S1b, a second upper surface side tail S2a, and a second lower surface side tail S2b. The first upper surface side tail S1a is the part where the hydrogen concentration decreases from the first hydrogen concentration peak 101 toward the upper surface 21 side in the hydrogen chemical concentration distribution. The first lower surface side tail S1b is the part where the hydrogen concentration decreases from the first hydrogen concentration peak 101 toward the lower surface 23 side in the hydrogen chemical concentration distribution. The second upper surface side tail S2a is the part where the hydrogen concentration decreases from the second hydrogen concentration peak 102 toward the upper surface 21 side in the hydrogen chemical concentration distribution. The second lower surface side tail S2b is the part where the hydrogen concentration decreases from the second hydrogen concentration peak 102 toward the lower surface 23 side in the hydrogen chemical concentration distribution.

[0072] The first hydrogen concentration peak 101 in this example is the concentration peak based on the hydrogen injected from the lower surface 23 side. When hydrogen is injected from the lower surface 23 side, hydrogen is also distributed in the passage region between the lower surface 23 and the hydrogen injection position. Therefore, the hydrogen concentration of the first lower surface side tail S1b decreases more gently than that of the first upper surface side tail S1a. That is, the inclination of the first lower surface side tail S1b is smaller than that of the first upper surface side tail S1a.

[0073] The second hydrogen concentration peak 102 in this example is the concentration peak based on the hydrogen injected from the upper surface 21 side. When hydrogen is injected from the upper surface 21 side, hydrogen is also distributed in the passage region between the upper surface 21 and the hydrogen injection position. Therefore, the hydrogen concentration of the second upper surface side tail S2a decreases more gently than that of the second lower surface side tail S2b. That is, the inclination of the second upper surface side tail S2a is smaller than that of the second lower surface side tail S2b. The inclination of the tail of the concentration distribution in this specification can use the inclination of the tail within a predetermined distance from the position of the concentration peak. The predetermined distance can be 5 μm, can be 3 μm, and can also be 1 μm. The predetermined distance can be half of the distance between the depth position Z1 and the depth position Z2, or can be 1 / 4 of the distance between the depth position Z1 and the depth position Z2. In addition, the inclination of each tail can also be the inclination of the tail from the position of the concentration peak to the position where the concentration value becomes half of the peak value.

[0074] The hydrogen concentration distribution between the first hydrogen concentration peak 101 and the second hydrogen concentration peak 102 is set as the intermediate hydrogen distribution 103. In addition, the hydrogen chemical concentration of the intermediate hydrogen distribution 103 is set as the intermediate hydrogen concentration Hc. The intermediate hydrogen concentration Hc can use the minimum value of the hydrogen concentration between the depth position Z1 and the depth position Z2, or can use the average value of the hydrogen concentration between the depth position Z1 and the depth position Z2. In addition, the intermediate hydrogen concentration Hc can also use the average concentration of the flat part in the intermediate hydrogen distribution 103. The flat part in the concentration distribution is the part where the region with a substantially constant concentration is continuous in the depth direction for a predetermined length. The details of the flat part will be described later.

[0075] The hydrogen concentration distribution between the first hydrogen concentration peak 101 and the upper surface 21 of the semiconductor substrate 10 is set as the upper surface side hydrogen distribution 104. In addition, the hydrogen concentration of the upper surface side hydrogen distribution 104 is set as the upper surface side hydrogen concentration Hs1. The upper surface side hydrogen concentration Hs1 can use the minimum value of the hydrogen concentration between the depth position Z1 and the upper surface 21, or can use the average value of the hydrogen concentration between the depth position Z1 and the upper surface 21. The upper surface side hydrogen concentration Hs1 can also use the average concentration of the flat part closest to the depth position Z1 in the flat part of the upper surface side hydrogen distribution 104.

[0076] The hydrogen concentration distribution between the second hydrogen concentration peak 102 and the lower surface 23 of the semiconductor substrate 10 is set as the lower surface side hydrogen distribution 105. In addition, the hydrogen concentration of the lower surface side hydrogen distribution 105 is set as the lower surface side hydrogen concentration Hs2. The lower surface side hydrogen concentration Hs2 can use the minimum value of the hydrogen concentration between the depth position Z2 and the lower surface 23, or can use the average value of the hydrogen concentration between the depth position Z2 and the lower surface 23. The lower surface side hydrogen concentration Hs2 can also use the average concentration of the flat part closest to the depth position Z2 in the flat part of the lower surface side hydrogen distribution 105.

[0077] The intermediate hydrogen concentration Hc is different from either the upper surface side hydrogen concentration Hs1 or the lower surface side hydrogen concentration Hs2. In this example, in the region between the depth position Z1 and the depth position Z2, there are both hydrogen injected from the upper surface 21 side and hydrogen injected from the lower surface 23 side. Therefore, the intermediate hydrogen concentration Hc in this example is higher than either the upper surface side hydrogen concentration Hs1 or the lower surface side hydrogen concentration Hs2. The intermediate hydrogen concentration Hc can be 1.5 times or more, can be 2 times or more, and can also be 5 times or more with respect to either the upper surface side hydrogen concentration Hs1 or the lower surface side hydrogen concentration Hs2.

[0078] The donor concentration distribution has a first donor concentration peak 111 and a second donor concentration peak 112. The second donor concentration peak 112 is disposed at a position closer to the lower surface 23 side of the semiconductor substrate 10 than the first donor concentration peak 111. The first donor concentration peak 111 is disposed at the same depth position Z1 as the first hydrogen concentration peak 101. The second donor concentration peak 112 is disposed at the same depth position Z2 as the second hydrogen concentration peak 102. It should be noted that when the apex of one peak is included within the full width at half maximum of another peak, the two peaks may also be disposed at the same depth position.

[0079] The donor concentration distribution has a third upper surface side tail S3a, a third lower surface side tail S3b, a fourth upper surface side tail S4a, and a fourth lower surface side tail S4b. The third upper surface side tail S3a is the portion in the donor concentration distribution where the donor concentration decreases from the first donor concentration peak 111 toward the upper surface 21 side. The third lower surface side tail S3b is the portion in the donor concentration distribution where the donor concentration decreases from the first donor concentration peak 111 toward the lower surface 23 side. The fourth upper surface side tail S4a is the portion in the donor concentration distribution where the donor concentration decreases from the second donor concentration peak 112 toward the upper surface 21 side. The fourth lower surface side tail S4b is the portion in the donor concentration distribution where the donor concentration decreases from the second donor concentration peak 112 toward the lower surface 23 side.

[0080] Each donor concentration peak has a shape similar to the corresponding hydrogen concentration peak. In this example, the donor concentration of the third lower surface side tail S3b decreases more gently than that of the third upper surface side tail S3a. That is, the inclination of the third lower surface side tail S3b is smaller than that of the third upper surface side tail S3a. In addition, the donor concentration of the fourth upper surface side tail S4a decreases more gently than that of the fourth lower surface side tail S4b. That is, the inclination of the fourth upper surface side tail S4a is smaller than that of the fourth lower surface side tail S4b.

[0081] The donor concentration distribution between the first donor concentration peak 111 and the second donor concentration peak 112 is defined as an intermediate donor distribution 113. In addition, the donor concentration of the intermediate donor distribution 113 is defined as an intermediate donor concentration Dc. The intermediate donor concentration Dc may use the minimum value of the donor concentration between the depth position Z1 and the depth position Z2, or may use the average value of the donor concentration between the depth position Z1 and the depth position Z2. In addition, the intermediate donor concentration Dc may also use the average concentration of the flat portion in the intermediate donor distribution 113.

[0082] The donor concentration distribution between the first donor concentration peak 111 and the upper surface 21 of the semiconductor substrate 10 is defined as the upper surface side donor distribution 114. In addition, the donor concentration of the upper surface side donor distribution 114 is defined as the upper surface side donor concentration Ds1. The upper surface side donor concentration Ds1 can use the minimum value of the donor concentration between the depth position Z1 and the upper surface 21, or can use the average value of the donor concentration between the depth position Z1 and the upper surface 21. The upper surface side donor concentration Ds1 can also use the average concentration of the flat part closest to the depth position Z1 in the flat part of the upper surface side donor distribution 114.

[0083] The donor concentration distribution between the second donor concentration peak 112 and the lower surface 23 of the semiconductor substrate 10 is defined as the lower surface side donor distribution 115. In addition, the donor concentration of the lower surface side donor distribution 115 is defined as the lower surface side donor concentration Ds2. The lower surface side donor concentration Ds2 can use the minimum value of the donor concentration between the depth position Z2 and the lower surface 23, or can use the average value of the donor concentration between the depth position Z2 and the lower surface 23. The lower surface side donor concentration Ds2 can also use the average concentration of the flat part closest to the depth position Z2 in the flat part of the lower surface side donor distribution 115.

[0084] The intermediate donor concentration Dc is different from either the upper surface side donor concentration Ds1 or the lower surface side donor concentration Ds2. In this example, the intermediate donor concentration Dc is higher than either the upper surface side donor concentration Ds1 or the lower surface side donor concentration Ds2. The intermediate donor concentration Dc can be 1.5 times or more, can be 2 times or more, and can also be 5 times or more with respect to either the upper surface side donor concentration Ds1 or the lower surface side donor concentration Ds2.

[0085] In this example, any one of the intermediate donor concentration Dc, the upper surface side donor concentration Ds1, and the lower surface side donor concentration Ds2 is higher than the bulk donor concentration Db. The intermediate donor concentration Dc can be 1×10 13 / cm 3 or more and 1×10 15 / cm 3 or less. The intermediate donor concentration Dc can be 5×10 13 / cm 3 or more, and can also be 1×10 14 / cm 3 or more. The intermediate hydrogen concentration Hc can be 10 times or more, can be 50 times or more, and can also be 100 times or more of the intermediate donor concentration Dc.

[0086] As Figure 1As shown, by injecting hydrogen ions in such a way that passage region 106-1 and passage region 106-2 overlap, it is possible to adjust the donor concentration throughout the entire depth direction of semiconductor substrate 10. In addition, since hydrogen ions are injected from both the upper surface 21 and the lower surface 23, damage to the insulating film and the like can be reduced. In addition, since depth position Z1 and depth position Z2 are made different, it is possible to suppress the peaks of the hydrogen chemical concentration and the donor concentration from becoming too large.

[0087] The hydrogen chemical concentration Hp1 of the first hydrogen concentration peak 101 and the hydrogen chemical concentration Hp2 of the second hydrogen concentration peak 102 may be the same or different. The donor concentration Dp1 of the first donor concentration peak 111 and the donor concentration Dp2 of the second donor concentration peak 112 may be the same or different.

[0088] In Figure 2 the example, depth position Z1 is arranged on the upper surface 21 side of semiconductor substrate 10. In addition, depth position Z2 is arranged on the lower surface 23 side of semiconductor substrate 10. It should be noted that the upper surface 21 side refers to the region between the center Zc in the depth direction of semiconductor substrate 10 and the upper surface 21. The lower surface 23 side refers to the region between the center Zc in the depth direction of semiconductor substrate 10 and the lower surface 23. In addition, the central position in the depth direction of the region on the lower surface 23 side of semiconductor substrate 10 is set as Zc2. Similarly, the central position in the depth direction of the region on the upper surface 21 side is set as Zc1. The depth position Z1 in this example is arranged between depth position Zc and Zc1. In addition, depth position Z2 is arranged between depth position Zc and Zc2. However, the arrangement of depth positions Z1 and Z2 is not limited to Figure 2 the example.

[0089] Figure 3 is a diagram for explaining the flat part 150 in the concentration distribution. Although the flat part 150 in the donor concentration distribution is explained in Figure 3 , the same definition can also be used for the flat part in the hydrogen chemical concentration distribution. In Figure 3 , a part of the first donor concentration peak 111 and the donor distribution 114 on the upper surface side is enlarged.

[0090] It can be considered that in the passage region 106 through which hydrogen ions have passed (refer to Figure 1) Except in the vicinity of the depth positions Z1 and Z2, the vacancies (V, VV, etc.) generated by the passage of hydrogen are distributed in the depth direction with a substantially uniform concentration. In addition, it can be considered that the oxygen (O) implanted during the manufacture of the semiconductor substrate 10, etc. is also uniformly distributed in the depth direction. Further, in the passage region 106, due to the diffusion of hydrogen at each hydrogen concentration peak, there is a sufficient amount of hydrogen. Therefore, the VOH defects formed by the vacancies, oxygen, and hydrogen are present substantially uniformly in the passage region 106.

[0091] Therefore, in the passage region 106 except in the vicinity of the depth positions Z1 and Z2, there is a flat portion 150 formed by the substantially uniform distribution of VOH defects that function as donors. The donor concentration in the flat portion 150 is substantially constant in the depth direction. That the donor concentration is substantially constant in the depth direction may mean, for example, that the difference between the maximum value Dmax and the minimum value Dmin of the donor concentration is within 50% of the maximum value Dmax of the donor concentration over a predetermined length in the depth direction and is continuous. This difference may be 30% or less of the maximum value Dmax of the donor concentration in this region, or may be 10% or less of the maximum value Dmax of the donor concentration in this region.

[0092] Alternatively, with respect to the average concentration of the donor concentration distribution in a predetermined range in the depth direction, the value of the donor concentration distribution may be within ±50% of the average concentration of the donor concentration distribution, may be within ±30% of the average concentration of the donor concentration distribution, or may be within ±10% of the average concentration of the donor concentration distribution. The predetermined length in the depth direction may be 5 μm, may be 10 μm, or may be 15 μm. In Figure 3 the example, when the interval defined by two depth positions Zs and Ze is 5 μm or more and the difference between the maximum value Dmax and the minimum value Dmin of the donor concentration in this interval is within 50% of the maximum value Dmax of the donor concentration, this interval is taken as the flat portion 150.

[0093] In Figure 3 the flat portion 150 of the donor distribution 114 on the upper surface side has been described. The flat portion 150 may be arranged in the donor distribution 115 on the lower surface side, or may be arranged in both the donor distribution 114 on the upper surface side and the donor distribution 115 on the lower surface side. Further, the flat portion 150 may be arranged in the intermediate donor distribution 113.

[0094] Figure 4 Shows Figure 1Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line. In this example, the depth position Z1 is arranged between the depth position Zc1 and the upper surface 21, and the depth position Z2 is arranged between the depth position Zc2 and the lower surface 23. That is, the first hydrogen concentration peak 101 and the first donor concentration peak 111 are arranged between the depth position Zc1 and the upper surface 21, and the second hydrogen concentration peak 102 and the second donor concentration peak 112 are arranged between the depth position Zc2 and the lower surface 23. Other configurations are the same as those in Figure 2 the example shown.

[0095] According to this example, the regions of the intermediate hydrogen distribution 103 and the intermediate donor distribution 113 can be formed wider. That is, the region with a high donor concentration can be formed wider in the depth direction. In addition, it is easy for the first donor concentration peak 111 to function as at least a part of the N-type region formed on the upper surface 21 side of the semiconductor substrate 10, and for the second donor concentration peak 112 to function as at least a part of the N-type region formed on the lower surface 23 side of the semiconductor substrate 10. The N-type region on the upper surface 21 side is, for example, the storage region described later. The N-type region on the lower surface 23 side is, for example, the buffer region described later. Thus, donors with a concentration higher than the bulk donor concentration Db can be formed throughout the entire depth direction of the semiconductor substrate 10, and the formation of unnecessary donor concentration peaks can be prevented.

[0096] Figure 5 Shows Figure 1 another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line. In this example, both the depth position Z1 and the depth position Z2 are arranged on the upper surface 21 side of the semiconductor substrate 10. Other configurations are the same as those in Figure 2 the example shown.

[0097] According to this example, it is easy for the first donor concentration peak 111 and the second donor concentration peak 112 to function as at least a part of the N-type region formed on the upper surface 21 side of the semiconductor substrate 10. The N-type region on the upper surface 21 side is, for example, the storage region described later.

[0098] Figure 6 Shows Figure 1 another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line. In this example, both the depth position Z1 and the depth position Z2 are arranged on the lower surface 23 side of the semiconductor substrate 10. Other configurations are the same as those in Figure 2 the example shown.

[0099] According to this example, it is easy for the first donor concentration peak 111 and the second donor concentration peak 112 to function as at least a part of the N-type region formed on the lower surface 23 side of the semiconductor substrate 10. The N-type region on the lower surface 23 side is, for example, a buffer region described later.

[0100] Figure 7 Shows Figure 1 Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line of. In this example, the concentrations of each peak and each distribution are different. The depth position of each peak is the same as in a certain way described in Figures 2 to 6 .

[0101] The hydrogen chemical concentration Hp1 of the first hydrogen concentration peak 101 in this example is higher than the hydrogen chemical concentration Hp2 of the second hydrogen concentration peak 102. Similarly, the donor concentration Dp1 of the first donor concentration peak 111 is higher than the donor concentration Dp2 of the second donor concentration peak 112.

[0102] In this example, the dose of hydrogen ions from the lower surface 23 is higher than the dose of hydrogen ions from the upper surface 21. Therefore, the hydrogen chemical concentration of the hydrogen distribution 105 on the lower surface side is higher than the hydrogen chemical concentration of the hydrogen distribution 104 on the upper surface side. For example, the hydrogen chemical concentration at a position at a distance Zx from the first hydrogen concentration peak 101 in the hydrogen distribution 105 on the lower surface side is higher than the hydrogen chemical concentration at a position at the same distance Zx from the second hydrogen concentration peak 102 in the hydrogen distribution 104 on the upper surface side. The distance Zx is an arbitrary distance within the range of each distribution.

[0103] In the donor concentration distribution, the donor concentration of the donor distribution 115 on the lower surface side is also higher than the donor concentration of the donor distribution 114 on the upper surface side. For example, the donor concentration at a position at a distance Zx from the first donor concentration peak 111 in the donor distribution 115 on the lower surface side is higher than the donor concentration at a position at the same distance Zx from the second donor concentration peak 112 in the donor distribution 114 on the upper surface side.

[0104] Figure 8 Shows Figure 1 Another example of the hydrogen chemical concentration distribution and the donor concentration distribution in the depth direction at the position shown by the A-A line of. In this example, the concentrations of each peak and each distribution are different. The depth position of each peak is the same as in a certain way described in Figures 2 to 6 .

[0105] The hydrogen chemical concentration Hp2 of the second hydrogen concentration peak 102 in this example is higher than the hydrogen chemical concentration Hp1 of the first hydrogen concentration peak 101. Similarly, the donor concentration Dp2 of the second donor concentration peak 112 is higher than the donor concentration Dp1 of the first donor concentration peak 111.

[0106] In this example, the dose of hydrogen ions from the upper surface 21 is higher than the dose of hydrogen ions from the lower surface 23. Therefore, the hydrogen chemical concentration of the hydrogen distribution 104 on the upper surface side is higher than the hydrogen chemical concentration of the hydrogen distribution 105 on the lower surface side. For example, the hydrogen chemical concentration at a position at a distance Zx from the second hydrogen concentration peak 102 in the hydrogen distribution 104 on the upper surface side is higher than the hydrogen chemical concentration at a position at the same distance Zx from the first hydrogen concentration peak 101 in the hydrogen distribution 105 on the lower surface side.

[0107] In the donor concentration distribution, the donor concentration of the donor distribution 114 on the upper surface side is also higher than the donor concentration of the donor distribution 115 on the lower surface side. For example, the donor concentration at a position at a distance Zx from the second donor concentration peak 112 in the donor distribution 114 on the upper surface side is higher than the donor concentration at a position at the same distance Zx from the first donor concentration peak 111 in the donor distribution 115 on the lower surface side. As Figures 2 to 8 explained, by adjusting the positions and concentrations of the respective hydrogen concentration peaks, the donor concentration distribution inside the semiconductor substrate 10 can be appropriately adjusted.

[0108] Figure 9 is a top view showing an example of the semiconductor device 100. In Figure 9 the positions where the respective components are projected onto the upper surface of the semiconductor substrate 10 are shown. In Figure 9 only a part of the components of the semiconductor device 100 are shown, and a part of the components are omitted.

[0109] The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 may have Figures 1 to 8 a hydrogen chemical concentration distribution and a donor concentration distribution in a certain mode as described in Figures 1 to 8 . However, the semiconductor substrate 10 may further have other concentration peaks different from the respective concentration peaks described in Figures 1 to 8 . Sometimes, hydrogen ions are implanted as in the buffer region 20 described later to form an N-type region in the semiconductor substrate 10. In this case, the hydrogen chemical concentration distribution may have hydrogen concentration peaks in addition to the hydrogen concentration peaks described in Figures 1 to 8 . In addition, sometimes N-type impurities other than hydrogen such as phosphorus are implanted as in the emitter region 12 described later to form an N-type region in the semiconductor substrate 10. In this case, the donor concentration distribution may have donor concentration peaks in addition to the donor concentration peaks described in

[0110] The semiconductor substrate 10 has an edge 162 in a top view. In this specification, the case of simply referred to as a top view means the case of observing from the upper surface side of the semiconductor substrate 10. The semiconductor substrate 10 in this example has two sets of edges 162 opposite to each other in a top view. In Figure 9 the X-axis and the Y-axis are parallel to a certain edge 162. In addition, the Z-axis is perpendicular to the upper surface of the semiconductor substrate 10.

[0111] An active portion 160 is provided on the semiconductor substrate 10. The active portion 160 is a region where a main current flows in the depth direction between the upper surface and the lower surface of the semiconductor substrate 10 when the semiconductor device 100 operates. An emission electrode is provided above the active portion 160, but is omitted in Figure 9 this case.

[0112] At least one of a transistor portion 70 including transistor elements such as IGBTs and a diode portion 80 including diode elements such as freewheeling diodes (FWDs) is provided in the active portion 160. In Figure 9 this example, the transistor portion 70 and the diode portion 80 are alternately arranged along a predetermined arrangement direction (the X-axis direction in this example) on the upper surface of the semiconductor substrate 10. In another example, only one of the transistor portion 70 and the diode portion 80 may be provided in the active portion 160.

[0113] In Figure 9 this case, the symbol "I" is marked in the region where the transistor portion 70 is arranged, and the symbol "F" is marked in the region where the diode portion 80 is arranged. In this specification, the direction perpendicular to the arrangement direction in a plan view is sometimes referred to as the extending direction (the Y-axis direction in Figure 9 this case). The transistor portion 70 and the diode portion 80 may each have a long side in the extending direction. That is, the length of the transistor portion 70 in the Y-axis direction is larger than the width in the X-axis direction. Similarly, the length of the diode portion 80 in the Y-axis direction is larger than the width in the X-axis direction. The extending direction of the transistor portion 70 and the diode portion 80 may be the same as the long side direction of each of the trench portions described later.

[0114] The diode portion 80 has an N+-type cathode region in the region in contact with the lower surface of the semiconductor substrate 10. In this specification, the region where the cathode region is provided is referred to as the diode portion 80. That is, the diode portion 80 is the region that overlaps the cathode region in a plan view. On the lower surface of the semiconductor substrate 10, a P+-type collector region may be provided in the region other than the cathode region. In this specification, the extended region 81 formed by extending the diode portion 80 along the Y-axis direction to the gate wiring described later is sometimes included in the diode portion 80. A collector region is provided on the lower surface of the extended region 81.

[0115] The transistor portion 70 has a P+-type collector region in the region in contact with the lower surface of the semiconductor substrate 10. In addition, the transistor portion 70 is periodically provided with an N-type emitter region, a P-type base region, and a gate structure having a gate conductive portion and a gate insulating film on the upper surface side of the semiconductor substrate 10.

[0116] 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 the end edge 162. The vicinity of the end edge 162 refers to the region between the end edge 162 and the emission 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.

[0117] A gate potential is applied to the gate pad 164. The gate pad 164 is electrically connected to the conductive portion of the gate trench portion of the active portion 160. The semiconductor device 100 includes a gate wiring that connects the gate pad 164 and the gate trench portion. In Figure 9 it, the gate wiring is marked with diagonal hatching.

[0118] The gate wiring of this example has an outer peripheral gate wiring 130 and an active side gate wiring 131. The outer peripheral gate wiring 130 is disposed between the active portion 160 and the end edge 162 of the semiconductor substrate 10 in a top view. The outer peripheral gate wiring 130 of this example surrounds the active portion 160 in a top view. The region surrounded by the outer peripheral gate wiring 130 in a top view may also be regarded as the active portion 160. In addition, the outer peripheral gate wiring 130 is connected to the gate pad 164. The outer peripheral gate wiring 130 is disposed above the semiconductor substrate 10. The outer peripheral gate wiring 130 may be a metal wiring including aluminum or the like.

[0119] The active side gate wiring 131 is provided in the active portion 160. By providing the active side gate wiring 131 in the active portion 160, it is possible to reduce the deviation of the wiring length from the gate pad 164 for each region of the semiconductor substrate 10.

[0120] The active side gate wiring 131 is connected to the gate trench portion of the active portion 160. The active side gate wiring 131 is disposed above the semiconductor substrate 10. The active side gate wiring 131 may be a wiring formed of a semiconductor such as polysilicon doped with impurities.

[0121] The active side gate wiring 131 may be connected to the outer peripheral gate wiring 130. The active side gate wiring 131 of this example is provided to extend from one outer peripheral gate wiring 130 to the other outer peripheral gate wiring 130 in the X-axis direction so as to cross the active portion 160 at substantially the center in the Y-axis direction. When the active portion 160 is divided by the active side gate wiring 131, in each divided region, the transistor portion 70 and the diode portion 80 may be alternately arranged in the X-axis direction.

[0122] In addition, the semiconductor device 100 may also include a temperature sensing unit (not shown) formed of polysilicon or the like as a PN junction diode, and / or a current detection unit (not shown) that simulates the operation of the transistor unit provided in the active unit 160.

[0123] The semiconductor device 100 of this example includes an edge termination structure portion 90 between the active portion 160 and the end edge 162 when viewed from above. The edge termination structure portion 90 of this example is disposed between the peripheral gate wiring 130 and the end edge 162. The edge termination structure portion 90 alleviates the electric field concentration on the upper surface side of the semiconductor substrate 10. The edge termination structure portion 90 may include at least one of a protection ring, a field plate, and a surface electric field reduction that is disposed in a ring shape surrounding the active portion 160.

[0124] Figure 10 Yes Figure 9 It is an enlarged view of region C in. Region C is a region including the transistor portion 70, the diode portion 80, and the active side gate wiring 131. The semiconductor device 100 of this example includes: a gate trench portion 40, a dummy trench portion 30, a well region 11, an emitter region 12, a base region 14, and a contact region 15 provided inside the upper surface side of the semiconductor substrate 10. The gate trench portion 40 and the dummy trench portion 30 are each an example of a trench portion. In addition, the semiconductor device 100 of this example includes an emitter electrode 52 and an active side gate wiring 131 provided above the upper surface of the semiconductor substrate 10. The emitter electrode 52 and the active side gate wiring 131 are provided separately from each other.

[0125] 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 it is omitted in Figure 10 . In the interlayer insulating film of this example, contact holes 54 are provided so as to penetrate the interlayer insulating film. In Figure 10 , each contact hole 54 is marked with diagonal hatching.

[0126] 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 is in contact with the emitter region 12, the contact region 15, and the base region 14 on the upper surface of the semiconductor substrate 10 through the contact holes 54. In addition, the emitter electrode 52 is connected to the dummy conductive portion in the dummy trench portion 30 through the contact holes 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 front end in the Y-axis direction of the dummy trench portion 30.

[0127] The active-side gate wiring 131 is connected to the gate trench portion 40 through a contact hole provided in the interlayer insulating film. The active-side gate wiring 131 can be connected to the gate conductive portion of the gate trench portion 40 at the front end portion 41 in the Y-axis direction of the gate trench portion 40. The active-side gate wiring 131 is not connected to the dummy conductive portion in the dummy trench portion 30.

[0128] The emission electrode 52 is formed of a metal-containing material. In Figure 10 , the range where the emission electrode 52 is provided is shown. For example, at least a part of the region of the emission electrode 52 is formed of a metal alloy such as aluminum or an aluminum-silicon alloy such as AlSi, AlSiCu, etc. The emission electrode 52 can have a barrier metal formed of titanium and / or a titanium compound, etc. in the lower layer of the region formed of aluminum, etc. Further, in the contact hole, a plug formed by embedding tungsten, etc. in contact with the barrier metal and aluminum, etc. can be provided.

[0129] The well region 11 is provided to overlap with the active-side gate wiring 131. The well region 11 is provided to extend with a predetermined width also in a range that does not overlap with the active-side gate wiring 131. The well region 11 in this example is provided at the end portion in the Y-axis direction away from the contact hole 54 toward the active-side gate wiring 131 side. The well region 11 is a region of the second conductivity type having a doping concentration higher than the doping concentration of the base region 14. The base region 14 in this example is P-type, and the well region 11 is P+-type.

[0130] The transistor portion 70 and the diode portion 80 each have a plurality of trench portions arranged along the arrangement direction. In the transistor portion 70 in this example, one or more gate trench portions 40 and one or more dummy trench portions 30 are alternately provided along the arrangement direction. In the diode portion 80 in this example, a plurality of dummy trench portions 30 are provided along the arrangement direction. The gate trench portion 40 is not provided in the diode portion 80 in this example.

[0131] The gate trench portion 40 in this example can have two linear portions 39 (portions of the trench that are linear along the extension direction) extending along an extension direction perpendicular to the arrangement direction, and a front end portion 41 connecting the two linear portions 39. Figure 10 The extension direction in

[0132] is the Y-axis direction. At least a part of the front end portion 41 is preferably provided to be curved in a plan view. By connecting the end portions in the Y-axis direction of the two linear portions 39 with the front end portion 41, the electric field concentration at the end portions of the linear portions 39 can be alleviated.

[0133] In the transistor section 70, dummy trench sections 30 are provided between respective straight portions 39 of the gate trench section 40. One dummy trench section 30 may be provided between the respective straight portions 39, or a plurality of dummy trench sections 30 may be provided. The dummy trench section 30 may have a straight shape extending in the extending direction, or may have a straight portion 29 and a front end portion 31, similarly to the gate trench section 40. Figure 10 The semiconductor device 100 shown includes both a dummy trench section 30 having a straight shape without a front end portion 31 and a dummy trench section 30 having a front end portion 31.

[0134] The diffusion depth of the well region 11 may be deeper than the depths of the gate trench section 40 and the dummy trench section 30. The Y-axis direction ends of the gate trench section 40 and the dummy trench section 30 are provided in the well region 11 in a plan view. That is, at the Y-axis direction ends of each trench section, the bottom in the depth direction of each trench section is covered by the well region 11. Thereby, the electric field concentration at the bottom of each trench section can be alleviated.

[0135] In the arrangement direction, a mesa portion is provided between each trench section. The mesa portion refers to a region in the semiconductor substrate 10 sandwiched by the trench sections. 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 section. The mesa portion in this example is provided to extend along the trench in the extending direction (Y-axis direction) on the upper surface of the semiconductor substrate 10. In this example, a mesa portion 60 is provided in the transistor section 70, and a mesa portion 61 is provided in the diode section 80. In this specification, when simply referred to as the mesa portion, it means each of the mesa portion 60 and the mesa portion 61.

[0136] A base region 14 is provided in each mesa portion. The region of the base region 14 exposed on the upper surface of the semiconductor substrate 10 in the mesa portion and configured to be closest to the active side gate wiring 131 is defined as the base region 14-e. In Figure 10 FIG., the base region 14-e disposed at one end in the extending direction of each mesa portion is shown, but the base region 14-e is also disposed at the other end of each mesa portion. At least one of the first conductivity type emitter region 12 and the second conductivity type contact region 15 may be provided in a region that can be sandwiched by the base region 14-e in a plan view in each mesa portion. The emitter region 12 in this example is of N+ type, and the contact region 15 is of P+ type. The emitter region 12 and the contact region 15 may be provided between the base region 14 and the upper surface of the semiconductor substrate 10 in the depth direction.

[0137] The mesa surface portion 60 of the transistor section 70 has an emitter region 12 exposed on the upper surface of the semiconductor substrate 10. The emitter region 12 is arranged to be in contact with the gate trench portion 40. The mesa surface 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.

[0138] The contact region 15 and the emitter region 12 in the mesa surface portion 60 are respectively arranged from one trench portion on one side in the X-axis direction to the other trench portion. As an example, the contact region 15 and the emitter region 12 of the mesa surface portion 60 are alternately arranged along the extending direction (Y-axis direction) of the trench portion.

[0139] In another example, the contact region 15 and the emitter region 12 of the mesa surface portion 60 may be arranged in a striped shape along the extending direction (Y-axis direction) of the trench portion. For example, the emitter region 12 is provided in the region in contact with the trench portion, and the contact region 15 is provided in the region sandwiched by the emitter regions 12.

[0140] The emitter region 12 is not provided in the mesa surface portion 61 of the diode section 80. A base region 14 and a contact region 15 may be provided on the upper surface of the mesa surface portion 61. The region sandwiched by the base regions 14-e in the upper surface of the mesa surface portion 61 may be provided with the contact region 15 in a manner of being in contact with each base region 14-e. The base region 14 may be provided in the region sandwiched by the contact regions 15. The base region 14 may be arranged in the entire region sandwiched by the contact regions 15.

[0141] Contact holes 54 are provided above each mesa surface portion. The contact holes 54 are arranged in the region sandwiched by the base regions 14-e. The contact holes 54 in this example are provided above the regions of the contact region 15, the base region 14, and the emitter region 12. The contact holes 54 are not provided in the regions corresponding to the base regions 14-e and the well region 11. The contact holes 54 may be arranged at the center in the arrangement direction (X-axis direction) of the mesa surface portions 60.

[0142] In the diode section 80, an N+-type cathode region 82 is provided in the region adjacent to the lower surface of the semiconductor substrate 10. On the lower surface of the semiconductor substrate 10, a P+-type collector region 22 may be provided in the region where the cathode region 82 is not provided. The cathode region 82 and the collector region 22 are provided between the lower surface 23 of the semiconductor substrate 10 and the buffer region 20. In Figure 10 the boundary between the cathode region 82 and the collector region 22 is shown by a dashed line.

[0143] The cathode region 82 is configured to be away from the well region 11 in the Y-axis direction. Thus, the distance between the P-type region (well region 11) with a relatively high doping concentration formed to a deep position and the cathode region 82 can be ensured, and the breakdown voltage can be increased. The end portion of the cathode region 82 in the Y-axis direction is configured to be farther from the well region 11 than the end portion of the contact hole 54 in the Y-axis direction. In another example, the end portion of the cathode region 82 in the Y-axis direction may be disposed between the well region 11 and the contact hole 54.

[0144] Figure 11 is a diagram showing Figure 10 an example of the b-b cross section in. The b-b cross section is the XZ plane passing through the emitter region 12 and the cathode region 82. The semiconductor device 100 in this example has, in this cross section: a semiconductor substrate 10, an interlayer insulating film 38, an emitter electrode 52, and a collector electrode 24.

[0145] The interlayer insulating film 38 is provided on the upper surface of the semiconductor substrate 10. The interlayer insulating film 38 is a film including at least one of an insulating film such as silicate glass doped with impurities such as boron or phosphorus, a thermal oxide film, and other insulating films. The contact hole 54 described in Figure 10 is provided in the interlayer insulating film 38.

[0146] The emitter electrode 52 is provided above the interlayer insulating film 38. The emitter electrode 52 is in contact with the upper surface 21 of the semiconductor substrate 10 through the contact hole 54 of the interlayer insulating film 38. The collector electrode 24 is provided on the lower surface 23 of the semiconductor substrate 10. The emitter electrode 52 and the collector electrode 24 are formed of a metal material such as aluminum. In this specification, the direction (Z-axis direction) connecting the emitter electrode 52 and the collector electrode 24 is referred to as the depth direction.

[0147] The semiconductor substrate 10 has an N-type or N- type drift region 18. The drift regions 18 are respectively provided in the transistor portion 70 and the diode portion 80.

[0148] On the mesa portion 60 of the transistor portion 70, an N+-type emitter region 12 and a P-type base region 14 are sequentially provided from the upper surface 21 side of the semiconductor substrate 10. The drift region 18 is provided below the base region 14. An N+-type storage region 16 may be provided on the mesa portion 60. The storage region 16 is disposed between the base region 14 and the drift region 18.

[0149] The emitter region 12 is exposed on the upper surface 21 of the semiconductor substrate 10 and is provided to be in contact with the gate trench portion 40. The emitter region 12 may be in contact with the trench portions on both sides of the mesa portion 60. The doping concentration of the emitter region 12 is higher than the doping concentration of the drift region 18.

[0150] 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.

[0151] The accumulation region 16 is provided below the base region 14. The accumulation region 16 is an N+-type region with a doping concentration higher than that of 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 improved, and the conduction voltage can be reduced. The accumulation region 16 may be provided to cover the entire lower surface of the base region 14 in each mesa portion 60.

[0152] A P-type base region 14 is provided on the mesa portion 61 of the diode portion 80 in contact with the upper surface 21 of the semiconductor substrate 10. A drift region 18 is provided below the base region 14. In the mesa portion 61, an accumulation region 16 may also be provided below the base region 14.

[0153] In the transistor portion 70 and the diode portion 80, an N+-type buffer region 20 may be provided below the drift region 18 respectively. The doping concentration of the buffer region 20 is higher than that of the drift region 18. The buffer region 20 has a concentration peak 25 with a doping concentration higher than that of the drift region 18. The doping concentration of the concentration peak 25 refers to the doping concentration at the apex of the concentration peak 25. In addition, the doping concentration of the drift region 18 may use the average value of the doping concentrations in a region where the doping concentration distribution is substantially flat. The doping concentration of the drift region 18 may be the average value of the doping concentrations of the flat portion 150 described in Figure 3 the flat portion 150 described in

[0154] The buffer region 20 of this example has three or more concentration peaks 25 in the depth direction (Z-axis direction) of the semiconductor substrate 10. The concentration peaks 25 of the buffer region 20 may be provided at the same depth position as, for example, the concentration peaks of hydrogen (protons) or phosphorus. The buffer region 20 may function as a field stop layer to prevent the depletion layer extending from the lower end of the base region 14 from reaching the P+-type collector region 22 and the N+-type cathode region 82.

[0155] In the transistor portion 70, a P+-type collector region 22 is provided below the buffer region 20. The acceptor concentration of the collector region 22 is higher than that of the base region 14. The collector region 22 may contain the same acceptor as the base region 14, or may contain an acceptor different from that of the base region 14. The acceptor of the collector region 22 is, for example, boron.

[0156] In the diode section 80, an N+-type cathode region 82 is provided under the buffer region 20. The donor concentration of the cathode region 82 is higher than that of the drift region 18. The donor of the cathode region 82 is, for example, hydrogen or phosphorus. It should be noted that the elements serving as donors and acceptors in each region are not limited to the above examples. The collector region 22 and the cathode region 82 are exposed on the lower surface 23 of the semiconductor substrate 10 and are connected to the collector electrode 24. The collector electrode 24 can 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.

[0157] On the upper surface 21 side of the semiconductor substrate 10, one or more gate trench portions 40 and one or more dummy trench portions 30 are provided. Each trench portion penetrates the base region 14 from the upper surface 21 of the semiconductor substrate 10 and reaches the drift region 18. In a region where at least one of the emitter region 12, the contact region 15, and the storage region 16 is provided, each trench portion also penetrates these doped regions and reaches the drift region 18. The trench portion penetrating the doped region is not limited to being manufactured in the order of forming the trench portion after forming the doped region. Forming the doped region between the trench portions after forming the trench portion is also included in the trench portion penetrating the doped region.

[0158] As described above, the gate trench portion 40 and the dummy trench portion 30 are provided in the transistor section 70. The dummy trench portion 30 is provided in the diode section 80, and the gate trench portion 40 is not provided. In this example, the boundary in the X-axis direction between the diode section 80 and the transistor section 70 is the boundary between the cathode region 82 and the collector region 22.

[0159] The gate trench portion 40 has a gate trench, a gate insulating film 42, and a gate conductive portion 44. The gate trench is provided on the upper surface 21 of the semiconductor substrate 10. The gate insulating film 42 is provided to cover the inner wall of the gate trench. The gate insulating film 42 can be formed by oxidizing or nitriding the semiconductor on the inner wall of the gate trench. The gate conductive portion 44 is provided at a position closer to the inside than the gate insulating film 42 inside the gate trench. That is, the gate insulating film 42 insulates the gate conductive portion 44 from the semiconductor substrate 10. The gate conductive portion 44 is formed of a conductive material such as polysilicon.

[0160] The gate conductive portion 44 can be provided to be longer than the base region 14 in the depth direction. In the cross section, the gate trench portion 40 on the upper surface 21 of the semiconductor substrate 10 is covered with an interlayer insulating film 38. The gate conductive portion 44 is electrically connected to the gate wiring. If a predetermined gate voltage is applied to the gate conductive portion 44, a channel formed by an inversion layer of electrons is formed on the surface layer of the interface in the base region 14 that contacts the gate trench portion 40.

[0161] The dummy trench portion 30 may have the same structure as the gate trench portion 40 in this cross-section. The dummy trench portion 30 has a dummy trench, a dummy insulating film 32, and a dummy conductive portion 34. The dummy trench is provided on the upper surface 21 of the semiconductor substrate 10. The dummy conductive portion 34 is electrically connected to the emission electrode 52. The dummy insulating film 32 is provided to cover the inner wall of the dummy trench. The dummy conductive portion 34 is provided inside the dummy trench and at a position more 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 as the gate conductive portion 44 in the depth direction.

[0162] In this example, the gate trench portion 40 and the dummy trench portion 30 on the upper surface 21 of the semiconductor substrate 10 are covered with the interlayer insulating film 38. It should be noted that the bottoms of the dummy trench portion 30 and the gate trench portion 40 may be curved surfaces that bulge downward (curved in the cross-section).

[0163] As described in Figures 1 to 8 , the semiconductor substrate 10 has a first hydrogen concentration peak 101 and a first donor concentration peak 111 at the depth position Z1, and a second hydrogen concentration peak 102 and a second donor concentration peak 112 at the depth position Z2.

[0164] The depth position Z1 may be arranged within the accumulation region 16, may be arranged between the lower end position Zt of the trench portion and the upper end position Zf of the buffer region 20, or may be arranged within the buffer region 20. Similarly, for the depth position Z2, it may be arranged within the accumulation region 16, may be arranged between the lower end position Zt of the trench portion and the upper end position Zf of the buffer region 20, or may be arranged within the buffer region 20.

[0165] Figure 12 FIG. is a diagram showing another example of the through regions 106-1 and 106-2. In this example, the through regions 106-1 and 106-2 do not overlap. That is, the through regions 106-1 and 106-2 are arranged separated from each other in the depth direction.

[0166] In this example, hydrogen ions are implanted into the semiconductor substrate 10 from the upper surface 21 side to the depth position Z1 of the semiconductor substrate 10. In addition, hydrogen ions are implanted into the semiconductor substrate 10 from the lower surface 23 side to a depth position Z2 that is closer to the lower surface 23 side than the depth position Z1. The depth positions Z1 and Z2 in this example are arranged between the lower end position Zt of the trench portion and the upper end position Zf of the buffer region 20.

[0167] Figure 13 FIG. shows Figure 12A diagram showing an example of the doping concentration distribution at the D-D line in []. In this example, in addition to the donor concentration distribution based on VOH defects, the doping concentration distributions in each region are also shown.

[0168] Bulk donors such as phosphorus are distributed throughout the semiconductor substrate 10. The emitter region 12 contains an N-type dopant such as phosphorus. The base region 14 contains a P-type dopant such as boron. The accumulation region 16 contains an N-type dopant such as phosphorus or hydrogen.

[0169] The drift region 18 contains hydrogen in at least a part of the region. A first donor concentration peak 111 and a second donor concentration peak 112 are arranged in the drift region 18.

[0170] The buffer region 20 of this example has a plurality of concentration peaks 25-1, 25-2, 25-3, 25-4 in the doping concentration distribution. Each concentration peak 25 is formed by implanting hydrogen ions. The collector region 22 contains a P-type dopant such as boron.

[0171] Figure 14 is a diagram showing Figure 13 An example of the hydrogen chemical concentration distribution and the donor concentration distribution in the region near the depth positions Z1 and Z2 shown. In this example, for the region between the depth positions Z1 and Z2, hydrogen does not pass through. Therefore, VOH defects are not formed in this region. On the other hand, VOH defects are formed in the region between the depth position Z1 and the upper surface 21 and in the region between the depth position Z2 and the lower surface 23.

[0172] In this example, the intermediate donor concentration Dc in the intermediate donor distribution 113 between the depth positions Z1 and Z2 is lower than either the upper surface side donor concentration Ds1 in the upper surface side donor distribution 114 or the lower surface side donor concentration Ds2 in the lower surface side donor distribution 115. The intermediate donor concentration Dc can be the same as the bulk donor concentration Db. Either the upper surface side donor concentration Ds1 or the lower surface side donor concentration Ds2 is higher than the bulk donor concentration Db. The upper surface side donor concentration Ds1 and the lower surface side donor concentration Ds2 can be more than 2 times the intermediate donor concentration Dc, can be more than 3 times the intermediate donor concentration Dc, or can be more than 5 times the intermediate donor concentration Dc.

[0173] In this example, the depth positions Z1 and Z2 can be arranged in the same manner as Figures 2 to 8 the example shown. Among them, the depth positions Z1 and Z2 are preferably arranged between the depth positions Zt and Zf. For example, as Figure 5As shown, both the first hydrogen concentration peak 101 and the second hydrogen concentration peak 102 can be arranged on the upper surface 21 side of the semiconductor substrate 10. Thereby, the region of the intermediate donor distribution 113 with a lower donor concentration can be arranged on the upper surface 21 side of the semiconductor substrate 10. Depending on the structure of the semiconductor device 100, the electric field may tend to concentrate on the upper surface 21 side. Even in such a case, by arranging the intermediate donor distribution 113 on the upper surface 21 side, the electric field concentration on the upper surface 21 side can be alleviated.

[0174] In Figures 1 to 14 each of the examples shown, the distance in the depth direction between the depth positions Z1 and Z2 can be 1 / 2 or less of the thickness of the semiconductor substrate 10 in the depth direction. This distance can be 1 / 4 or less of the thickness, or can be 1 / 10 or less of the thickness. In Figure 13 the example of, by reducing this distance, the donor concentration of the semiconductor substrate 10 can be adjusted over a wide range in the depth direction.

[0175] Figure 15 is a diagram showing an example of a manufacturing method of the semiconductor device 100 described in Figures 1 to 14 . The manufacturing method includes a hydrogen injection step, and this hydrogen injection step includes an upper surface injection step of injecting hydrogen ions from the upper surface 21 of the semiconductor substrate 10 to a first depth position, and a lower surface injection step of injecting hydrogen ions from the lower surface 23 of the semiconductor substrate to a second depth position different from the first depth position. In Figure 15 , the lower surface injection step is step S1408. In Figure 15 , the upper surface injection step is one of steps S1412, S1413, S1414, S1415. The first depth position is one of the depth positions Z1 and Z2, and the second depth position is the other of the depth positions Z1 and Z2.

[0176] In this example, in step S1400, the upper surface structure of the semiconductor device 100 is formed. The upper surface structure refers to the structure provided on the upper surface 21 side of the semiconductor substrate 10, and includes, for example, a trench portion, an emitter region 12, a base region 14, a storage region 16, an interlayer insulating film 38, an emitter electrode 52, a gate wiring, and the like.

[0177] Next, in step S1402, the lower surface 23 side of the semiconductor substrate 10 is polished to adjust the thickness of the semiconductor substrate 10. Next, in step S1412, hydrogen ions can be injected from the upper surface 21 side of the semiconductor substrate 10. However, injecting hydrogen ions from the upper surface 21 side can also be performed at other times described later. In step S1412, hydrogen ions are injected to a depth position that is one of the depth positions Z1 or Z2. The depth position Z2 can be arranged between the depth position Z1 and the lower surface 23.

[0178] In Figures 1 to 8 the example of, in step S1412, hydrogen ions are implanted from the upper surface 21 to the depth position Z2. In addition, in Figures 12 to 14 the example of, in step S1412, hydrogen ions are implanted from the upper surface 21 to the depth position Z1.

[0179] Next, in step S1404, a P-type dopant is implanted into the collector region 22. In step S1404, an N-type dopant may also be implanted into the cathode region 82. Next, in step S1413, hydrogen ions may be implanted from the upper surface 21 side of the semiconductor substrate 10. Step S1413 is the same as step S1412. When step S1413 is performed, step S1412 may not be performed.

[0180] Next, in step S1406, a laser is irradiated to the region near the lower surface 23 to perform laser annealing. Thereby, the cathode region 82 and the collector region 22 are formed. When step S1412 or step S1413 is performed before step S1406, through the laser annealing in step S1406, excessive defects formed by hydrogen ion implantation can be recovered. In particular, in step S1412 or step S1413, when hydrogen ions are implanted from the upper surface 21 to the region on the lower surface 23 side, since the acceleration energy of the hydrogen ions becomes higher, excessive defects are likely to be formed. In this case, through step S1406, excessive defects near the lower surface 23 can be recovered.

[0181] Next, in step S1414, hydrogen ions may be implanted from the upper surface 21 side of the semiconductor substrate 10. Step S1414 is the same as step S1412. When step S1414 is performed, steps S1412 and S1413 may not be performed. Next, in step S1408, hydrogen ions are implanted from the lower surface 23 side. In step S1408, hydrogen ions are implanted from the lower surface 23 to one of the depth positions Z1 or Z2. As described above, the depth position of implanting hydrogen ions from the upper surface 21 side is different from the depth position of implanting hydrogen ions from the lower surface 23 side.

[0182] In Figures 1 to 8 the example of, in step S1408, hydrogen ions are implanted from the lower surface 23 to the depth position Z1. In addition, in Figures 12 to 14 the example of, in step S1408, hydrogen ions are implanted from the lower surface 23 to the depth position Z2.

[0183] Next, in step S1415, hydrogen ions can be implanted from the upper surface 21 side of the semiconductor substrate 10. Step S1415 is the same as step S1412. In the case of performing step S1415, steps S1412, S1413, and S1414 may not be performed. By performing step S1414 or step S1415 after step S1406, it is possible to suppress excessive recovery of vacancy defects near the lower surface 23 formed in step S1414 or step S1415 due to laser annealing. Therefore, the donor concentration of the semiconductor substrate 10 can be controlled with good accuracy.

[0184] Next, in step S1410, the semiconductor substrate 10 is heat-treated. In step S1410, the entire semiconductor substrate 10 can be heat-treated using an annealing furnace. Thereby, hydrogen diffuses, and the formation of VOH defects is promoted. The heat treatment temperature in step S1410 can be 350°C or higher and 380°C or lower. The upper limit of the heat treatment temperature can also be 360°C or lower. After step S1410, structures such as the collector electrode 24 are formed. Thereby, the semiconductor device 100 can be manufactured.

[0185] In addition, the heat treatment step shown in step S1410 can be performed twice, after implanting hydrogen from one of the upper surface 21 and the lower surface 23 and after implanting hydrogen from the other of the upper surface 21 and the lower surface 23. In addition, for the step of implanting hydrogen from the upper surface 21 and the step of implanting hydrogen from the lower surface 23, the one with the higher hydrogen acceleration energy can be performed first. In this case, heat treatment can also be performed each time hydrogen is implanted. More specifically, the temperature of the first heat treatment step after the hydrogen implantation step with the higher acceleration energy can be higher than the temperature of the second heat treatment step after the hydrogen implantation step with the lower acceleration energy. The temperature of the first heat treatment step can be 360°C or higher and 380°C or lower. The temperature of the second heat treatment step can be less than 360°C. Since the one with the higher acceleration energy is likely to form vacancy defects, VOH defects can be effectively formed by increasing the heat treatment temperature of the first heat treatment step.

[0186] As described above, the present invention has been described using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious that various changes or improvements can be made to the above embodiments by those skilled in the art. According to the claims, the embodiments with such changes or improvements can also be included in the technical scope of the present invention.

[0187] It should be noted that, as long as the execution order of each process such as actions, sequences, steps, and stages in the devices, systems, programs, and methods shown in the claims, the specification, and the drawings is not specifically indicated as "before...", "in advance", etc., and the results of previous processes are not used in subsequent processes, they can be implemented in any order. Even for convenience, the use of "first", "next", etc. to describe the action flow in the claims, the specification, and the drawings does not mean that it must be implemented in that order.

Claims

1. A semiconductor device, characterized in that, Comprising: A semiconductor substrate having an upper surface and a lower surface, The hydrogen chemical concentration distribution in the depth direction of the semiconductor substrate has: A first hydrogen concentration peak; and A second hydrogen concentration peak disposed at a position closer to the lower surface side of the semiconductor substrate than the first hydrogen concentration peak, The intermediate donor concentration between the first hydrogen concentration peak and the second hydrogen concentration peak is higher than the upper surface side donor concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate and the lower surface side donor concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate, or the intermediate donor concentration between the first hydrogen concentration peak and the second hydrogen concentration peak is lower than the upper surface side donor concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate and the lower surface side donor concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

2. The semiconductor device according to claim 1, wherein Both the lower surface side donor concentration and the upper surface side donor concentration are higher than the bulk donor concentration of the semiconductor substrate.

3. The semiconductor device according to claim 1, wherein The donor concentration distribution in the depth direction of the semiconductor substrate has flat portions both between the first hydrogen concentration peak and the upper surface of the semiconductor substrate and between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

4. The semiconductor device according to claim 1, wherein The donor concentration distribution in the depth direction of the semiconductor substrate has a flat portion between the first hydrogen concentration peak and the second hydrogen concentration peak.

5. The semiconductor device according to claim 1, wherein The distance in the depth direction between the first hydrogen concentration peak and the second hydrogen concentration peak is 1 / 2 or less of the thickness in the depth direction of the semiconductor substrate.

6. The semiconductor device according to claim 1, wherein The intermediate donor concentration is higher than both the upper surface side donor concentration and the lower surface side donor concentration.

7. The semiconductor device according to claim 6, wherein The intermediate hydrogen concentration between the first hydrogen concentration peak and the second hydrogen concentration peak is higher than both the upper surface side hydrogen concentration and the lower surface side hydrogen concentration, the upper surface side hydrogen concentration being the hydrogen concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate, and the lower surface side hydrogen concentration being the hydrogen concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

8. The semiconductor device according to claim 6 or 7, wherein The intermediate donor concentration is 1×10 13 / cm 3 or more and 1×10 15 / cm 3 or less.

9. The semiconductor device according to claim 6 or 7, wherein The intermediate donor concentration is 1.5 times or more with respect to each of the upper surface side donor concentration and the lower surface side donor concentration.

10. The semiconductor device according to claim 6 or 7, wherein The hydrogen chemical concentration distribution has: A first upper surface side tail, with the hydrogen concentration decreasing from the first hydrogen concentration peak toward the upper surface side, The first trailing on the lower surface side, where the hydrogen concentration decreases gently from the first hydrogen concentration peak toward the lower surface side compared to the first upper surface side; The second trailing on the lower surface side, where the hydrogen concentration decreases from the second hydrogen concentration peak toward the lower surface side; and The second trailing on the upper surface side, where the hydrogen concentration decreases gently from the second hydrogen concentration peak toward the upper surface side compared to the second lower surface side.

11. The semiconductor device according to claim 6 or 7, wherein the first hydrogen concentration peak is higher than the second hydrogen concentration peak, the donor concentration on the lower surface side is higher than the donor concentration on the upper surface side.

12. The semiconductor device according to claim 6 or 7, wherein the second hydrogen concentration peak is higher than the first hydrogen concentration peak, the donor concentration on the upper surface side is higher than the donor concentration on the lower surface side.

13. The semiconductor device according to claim 6 or 7, wherein the first hydrogen concentration peak is disposed between the center in the depth direction of the region on the upper surface side and the upper surface, the second hydrogen concentration peak is disposed between the center in the depth direction of the region on the lower surface side and the lower surface.

14. The semiconductor device according to claim 7, wherein the intermediate hydrogen concentration is 10 times or more the intermediate donor concentration.

15. The semiconductor device according to claim 6 or 7, wherein both the donor concentration on the lower surface side and the donor concentration on the upper surface side are higher than the bulk donor concentration of the semiconductor substrate.

16. The semiconductor device according to claim 6 or 7, wherein the donor concentration distribution in the depth direction of the semiconductor substrate has flat portions both between the first hydrogen concentration peak and the upper surface of the semiconductor substrate and between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

17. The semiconductor device according to claim 6 or 7, wherein the donor concentration distribution in the depth direction of the semiconductor substrate has a flat portion between the first hydrogen concentration peak and the second hydrogen concentration peak.

18. The semiconductor device according to claim 6 or 7, wherein the distance in the depth direction between the first hydrogen concentration peak and the second hydrogen concentration peak is 1 / 2 or less of the thickness in the depth direction of the semiconductor substrate.

19. The semiconductor device according to any one of claims 1 to 5, wherein the semiconductor substrate has: a drift region of a first conductivity type; a trench portion provided on the upper surface of the semiconductor substrate; and a buffer region of a first conductivity type provided between the drift region and the lower surface of the semiconductor substrate and having a higher concentration than that of the drift region, the first hydrogen concentration peak and the second hydrogen concentration peak are disposed in the depth direction between the lower end of the trench portion and the upper end of the buffer region, The intermediate donor concentration between the first hydrogen concentration peak and the second hydrogen concentration peak is lower than both the upper surface side donor concentration and the lower surface side donor concentration. The upper surface side donor concentration is the donor concentration between the first hydrogen concentration peak and the upper surface of the semiconductor substrate, and the lower surface side donor concentration is the donor concentration between the second hydrogen concentration peak and the lower surface of the semiconductor substrate.

20. The semiconductor device according to claim 19, wherein both the first hydrogen concentration peak and the second hydrogen concentration peak are arranged between the center in the depth direction of the semiconductor substrate and the upper surface.

21. A method for manufacturing a semiconductor device, which is the method for manufacturing the semiconductor device according to any one of claims 1 to 18, characterized in that, Comprising: a hydrogen injection step of injecting hydrogen ions from one of the upper surface and the lower surface of the semiconductor substrate to a first depth position, and injecting hydrogen ions from the other of the upper surface and the lower surface of the semiconductor substrate to a second depth position different from the first depth position; and a heat treatment step of performing heat treatment on the semiconductor substrate, wherein the second depth position is arranged between the first depth position and the one surface.

22. The manufacturing method of the semiconductor device according to claim 21, wherein the manufacturing method includes a laser annealing step of performing laser annealing on at least one of the upper surface and the lower surface of the semiconductor substrate, and the hydrogen injection step is performed after the laser annealing step.

23. A method of manufacturing a semiconductor device, which is the method of manufacturing a semiconductor device according to any one of claims 1 to 5, 19, and 20, characterized in that, Comprising: a hydrogen injection step of injecting hydrogen ions from one of the upper surface and the lower surface of the semiconductor substrate to a first depth position, and injecting hydrogen ions from the other of the upper surface and the lower surface of the semiconductor substrate to a second depth position different from the first depth position; and a heat treatment step of performing heat treatment on the semiconductor substrate, wherein the second depth position is arranged between the first depth position and the other surface, the semiconductor substrate has: a drift region of a first conductivity type; a trench portion provided on the upper surface of the semiconductor substrate; and a buffer region of a first conductivity type provided between the drift region and the lower surface of the semiconductor substrate and having a higher concentration than that of the drift region, wherein the first depth position and the second depth position are arranged between the lower end of the trench portion and the upper end of the buffer region in the depth direction of the semiconductor substrate.

24. The manufacturing method of the semiconductor device according to claim 23, wherein the manufacturing method includes a laser annealing step of performing laser annealing on at least one of the upper surface and the lower surface of the semiconductor substrate, and the hydrogen injection step is performed after the laser annealing step.

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