WO2021201235A1 - 半導体装置および半導体装置の製造方法 - Google Patents

半導体装置および半導体装置の製造方法 Download PDF

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WO2021201235A1
WO2021201235A1 PCT/JP2021/014179 JP2021014179W WO2021201235A1 WO 2021201235 A1 WO2021201235 A1 WO 2021201235A1 JP 2021014179 W JP2021014179 W JP 2021014179W WO 2021201235 A1 WO2021201235 A1 WO 2021201235A1
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concentration
region
donor
semiconductor substrate
peak
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French (fr)
Japanese (ja)
Inventor
源宜 窪内
吉村　尚
博 瀧下
美佐稀 内田
根本　道生
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Fuji Electric Co Ltd
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Fuji Electric Co Ltd
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Priority to DE112021000165.5T priority Critical patent/DE112021000165T5/de
Priority to CN202180005478.1A priority patent/CN114467180A/zh
Priority to JP2022511136A priority patent/JP7452632B2/ja
Publication of WO2021201235A1 publication Critical patent/WO2021201235A1/ja
Priority to US17/703,928 priority patent/US20220216055A1/en
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    • H10D84/611—Combinations of BJTs and one or more of diodes, resistors or capacitors
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    • H10P30/202—Ion implantation into wafers, substrates or parts of devices into semiconductor materials, e.g. for doping characterised by the semiconductor materials
    • H10P30/204—Ion implantation into wafers, substrates or parts of devices into semiconductor materials, e.g. for doping characterised by the semiconductor materials into Group IV semiconductors
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    • H10P30/20—Ion implantation into wafers, substrates or parts of devices into semiconductor materials, e.g. for doping
    • H10P30/28—Ion implantation into wafers, substrates or parts of devices into semiconductor materials, e.g. for doping characterised by an annealing step, e.g. for activation of dopants
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    • H10P32/10—Diffusion of dopants within, into or out of semiconductor bodies or layers
    • H10P32/17—Diffusion of dopants within, into or out of semiconductor bodies or layers characterised by the semiconductor material
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    • H10D84/80—Integrated devices formed in or on semiconductor substrates that comprise only semiconducting layers, e.g. on Si wafers or on GaAs-on-Si wafers characterised by the integration of at least one component covered by groups H10D12/00 or H10D30/00, e.g. integration of IGFETs
    • H10D84/811—Combinations of field-effect devices and one or more diodes, capacitors or resistors

Definitions

  • the present invention relates to a semiconductor device and a method for manufacturing the semiconductor device.
  • Patent Document 1 US2015 / 0050754
  • a semiconductor device having an upper surface and a lower surface and including a semiconductor substrate including a bulk donor.
  • the semiconductor device is arranged on the lower surface side of the semiconductor substrate, includes a hydrogen donor, and includes a first conductive type buffer region in which the doping concentration distribution in the depth direction of the semiconductor substrate has a single first doping concentration peak. You can do it.
  • the semiconductor device may be disposed between the buffer region and the upper surface of the semiconductor substrate, and may include a hydrogen donor and include a first conductive type high concentration region in which the donor concentration is higher than the bulk donor concentration.
  • the semiconductor device may be arranged between the buffer region and the lower surface of the semiconductor substrate, and may include a first conductive type or second conductive type lower surface region having a doping concentration higher than that of the high concentration region.
  • the doping concentration peak in the buffer region may be the concentration peak of the hydrogen donor.
  • the doping concentration peak in the buffer region may be the concentration peak of an N-type dopant other than the hydrogen donor.
  • the semiconductor device may include an impurity chemical concentration peak arranged on the upper surface side of the semiconductor substrate.
  • the upper hem where the impurity chemical concentration decreases from the apex of the impurity chemical concentration peak toward the upper surface side, has a higher impurity chemical concentration than the lower hem, where the impurity chemical concentration decreases from the apex of the impurity chemical concentration peak toward the lower surface side. It may decrease sharply.
  • the high concentration region may be provided from the doping concentration peak in the buffer region to the impurity chemical concentration peak.
  • the semiconductor device may include a hydrogen chemical concentration peak arranged at the same depth position as the first doping concentration peak in the buffer region.
  • the semiconductor device may include a second doping concentration peak located at the same depth as the impurity chemical concentration peak.
  • the impurity chemical concentration peak may be the chemical concentration peak of hydrogen.
  • Each concentration peak may have a lower hem whose concentration increases from the lower surface to the upper surface of the semiconductor substrate.
  • the slope of the lower hem of the second doping concentration peak is standardized by the slope of the lower hem of the impurity chemical concentration peak, and the slope of the lower hem of the first doping concentration peak is the slope of the hydrogen chemical concentration peak.
  • the inclination of the lower hem may be smaller than the standardized value.
  • the high concentration region may have a length of 50% or more of the thickness of the semiconductor substrate in the depth direction of the semiconductor substrate.
  • the high concentration region may have a length of 70 ⁇ m or more in the depth direction of the semiconductor substrate.
  • the donor concentration in the high concentration region may be at least twice the bulk donor concentration.
  • the donor concentration in the high concentration region may be 5 times or more the bulk donor concentration.
  • the bulk donor concentration (atoms / cm 3 ) is (9.2245 ⁇ 10 12 ) / x or more and (4.60123 ⁇ 10 16 ) / x or less. May be.
  • the bulk donor concentration (atoms / cm 3 ) may be greater than or equal to (9.2245 ⁇ 10 14 ) / x and less than or equal to (1.84049 ⁇ 10 16 ) / x.
  • the donor concentration (/ cm 3 ) at the center of the semiconductor substrate in the depth direction may be (9.2245 ⁇ 10 15 ) / x or more and (9.2245 ⁇ 10 16 ) / x or less.
  • a method for manufacturing a semiconductor device has an upper surface and a lower surface, and the charged particles are injected into the second position from the lower surface of the semiconductor substrate including the bulk donor, and the hydrogen chemical concentration distribution is distributed in the region on the lower surface side of the second position.
  • the manufacturing method may include a first annealing step of annealing the semiconductor substrate to form a high concentration region between the first position and the second position where the donor concentration is higher than the bulk donor concentration.
  • the manufacturing method may include a grinding step of grinding the lower surface side of the semiconductor substrate after the first annealing step to remove the region including the first position.
  • the manufacturing method may include a second injection step of injecting an N-type dopant from the lower surface of the semiconductor substrate to the lower surface side of the second position after the grinding step.
  • the manufacturing method may include a second injection step of injecting hydrogen ions from the lower surface of the semiconductor substrate to the lower surface side of the second position after the grinding step.
  • FIG. 1 shows the lattice defect density D V in the depth direction of hydrogen chemical concentration C H, each distribution of the doping concentration D d and the impurity chemical concentration C I.
  • Lattice defect density D V of the comparative example, the hydrogen chemical concentration C H shows each distribution of the doping concentration D d and the impurity chemical concentration C I.
  • It is a flowchart which shows an example of the manufacturing method of a semiconductor device 100. It is a flowchart which shows another example of the manufacturing method of a semiconductor device 100. It is a figure explaining the semiconductor device 100 which concerns on the manufacturing method of FIG. In the position shown in line A-A of FIG.
  • FIG. 6 shows the lattice defect density D V in the depth direction of hydrogen chemical concentration C H, each distribution of the doping concentration D d and the impurity chemical concentration C I. It is a figure which shows another example of the 1st doping concentration peak 111. It is a figure explaining the relationship between the hydrogen chemical concentration peak 131 and the first doping concentration peak 111. It is a figure explaining the relationship between the impurity chemical concentration peak 141 and the second doping concentration peak 121. It is a figure explaining the inclination of the lower hem 142. It is a figure explaining another definition of the standardization of the inclination of the lower hem 112. It is a figure explaining another definition of the standardization of the inclination of the lower hem 122.
  • 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”.
  • the upper surface is referred to as the upper surface and the other surface is referred to as the lower surface.
  • the “up” and “down” directions are not limited to the direction of gravity or the direction when the semiconductor device is mounted.
  • Cartesian coordinate axes of the X-axis, the Y-axis, and the Z-axis only specify the relative positions of the components and do not limit the specific direction.
  • the Z axis does not limit the height direction with respect to the ground.
  • the + Z-axis direction and the ⁇ Z-axis direction are opposite to each other. When the positive and negative directions are not described and the Z-axis direction is described, it means the direction parallel to the + Z-axis and the -Z-axis.
  • the X-axis and the Y-axis are orthogonal axes parallel to the upper surface and the lower surface of the semiconductor substrate. Further, the axis perpendicular to the upper surface and the lower surface of the semiconductor substrate is defined as the Z axis.
  • the direction of the Z axis may be referred to as a depth direction. Further, in the present specification, the direction parallel to the upper surface and the lower surface of the semiconductor substrate including the X-axis and the Y-axis may be referred to as a horizontal direction.
  • the region from the center in the depth direction of the semiconductor substrate to the upper surface of the semiconductor substrate may be referred to as the upper surface side.
  • the region from the center of the semiconductor substrate in the depth direction to the lower surface of the semiconductor substrate may be referred to as the lower surface side.
  • the center position of the semiconductor substrate in the depth direction may be referred to as Zc.
  • error When referred to as “same” or “equal” in the present specification, it may include a case where there is an error due to manufacturing variation or the like.
  • the error is, for example, within 10%.
  • the conductive type of the doping region doped with impurities is described as P type or N type.
  • an impurity may mean, in particular, either an N-type donor or a P-type acceptor, and may be referred to as a dopant.
  • doping means that a donor or acceptor is introduced into a semiconductor substrate to obtain a semiconductor exhibiting an N-type conductive type or a semiconductor exhibiting a P-type conductive type.
  • the doping concentration means the concentration of a donor or the concentration of an acceptor in a thermal equilibrium state.
  • the net doping concentration means the net concentration of the donor concentration as the concentration of positive ions and the acceptor concentration as the concentration of negative ions, including the polarity of the charge.
  • the donor concentration N D, the acceptor concentration and N A, the net doping concentration of the net at any position is N D -N A.
  • the net doping concentration may be simply referred to as a doping concentration.
  • the donor has the function of supplying electrons to the semiconductor.
  • the acceptor has a function of receiving electrons from a semiconductor.
  • Donors and acceptors are not limited to the impurities themselves.
  • a VOH defect in which pores (V), oxygen (O) and hydrogen (H) are bonded in a semiconductor functions as a donor that supplies electrons.
  • VOH defects are sometimes referred to herein as hydrogen donors.
  • the description of P + type or N + type means that the doping concentration is higher than that of P type or N type
  • the description of P-type or N-type means that the doping concentration is higher than that of P type or N type. It means that the concentration is low.
  • the unit system of the present specification is the SI unit system. The unit of length may be displayed in cm, but various calculations may be performed after converting to meters (m).
  • the chemical concentration refers to the atomic density of impurities measured regardless of the state of electrical activation.
  • the chemical concentration (atomic density) can be measured by, for example, secondary ion mass spectrometry (SIMS).
  • the net doping concentration described above can be measured by a voltage-capacity measurement method (CV method).
  • the carrier concentration measured by the spread resistance measurement method (SR method) may be used as the net doping concentration.
  • the carrier concentration measured by the CV method or the SR method may be a value in a thermal equilibrium state.
  • the donor concentration is sufficiently higher than the acceptor concentration, so that the carrier concentration in the region may be used as the donor concentration.
  • the carrier concentration in the region may be used as the acceptor concentration.
  • the doping concentration in the N-type region may be referred to as the donor concentration
  • the doping concentration in the P-type region may be referred to as the acceptor concentration.
  • the peak value may be used as the concentration of donor, acceptor or net doping in the region.
  • the concentration of donor, acceptor or net doping is substantially uniform, the average value of the concentration of donor, acceptor or net doping in the region may be used as the concentration of donor, acceptor or net doping.
  • at lesms / cm 3 or / cm 3 may be used to indicate the concentration per unit volume. This unit is used for the donor or acceptor concentration in the semiconductor substrate, or the chemical concentration. The at Budapestms notation may be omitted.
  • the carrier concentration measured by the SR method may be lower than the concentration of the donor or acceptor.
  • the carrier mobility of the semiconductor substrate may be lower than the value in the crystalline state. The decrease in carrier mobility occurs when carriers are scattered due to disorder of the crystal structure due to lattice defects or the like.
  • the concentration of the donor or acceptor calculated from the carrier concentration measured by the CV method or the SR method may be lower than the chemical concentration of the element indicating the donor or acceptor.
  • the donor concentration of phosphorus or arsenic as a donor in a silicon semiconductor, or the acceptor concentration of boron (boron) as an acceptor is about 99% of these chemical concentrations.
  • the donor concentration of hydrogen as a donor in a silicon semiconductor is about 0.1% to 10% of the chemical concentration of hydrogen.
  • Each concentration in the present specification may be a value at room temperature.
  • the value at room temperature may be the value at 300 K (Kelvin) (about 26.9 ° C.).
  • the peak position of the distribution may be referred to as the position where the particles are injected, the depth at which the particles are injected, or the like.
  • FIG. 1 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 made of a semiconductor material.
  • the semiconductor substrate 10 is a silicon substrate.
  • At least one of a transistor element such as an insulated gate bipolar transistor (IGBT) and a diode element such as a freewheeling diode (FWD) is formed on the semiconductor substrate 10.
  • a transistor element such as an insulated gate bipolar transistor (IGBT) and a diode element such as a freewheeling diode (FWD) is formed on the semiconductor substrate 10.
  • IGBT insulated gate bipolar transistor
  • FWD freewheeling diode
  • N-type bulk donors are distributed throughout.
  • the bulk donor is a donor due to the dopant contained in the ingot substantially uniformly during the production of the ingot that is the source of the semiconductor substrate 10.
  • the bulk donor in this example is an element other than hydrogen.
  • Bulk donor dopants are, but are not limited to, for example phosphorus, antimony, arsenic, selenium or sulfur.
  • the bulk donor in this example is phosphorus.
  • Bulk donors are also included in the P-type region.
  • the semiconductor substrate 10 may be a wafer cut out from a semiconductor ingot, or may be a chip obtained by fragmenting the wafer.
  • the semiconductor ingot may be manufactured by any one of the Czochralski method (CZ method), the magnetic field application type Czochralski method (MCZ method), and the float zone method (FZ method).
  • the ingot in this example is manufactured by the MCZ method.
  • the oxygen concentration contained in the substrate manufactured by the MCZ method is 1 ⁇ 10 17 to 7 ⁇ 10 17 / cm 3 .
  • the oxygen concentration contained in the substrate manufactured by the FZ method is 1 ⁇ 10 15 to 5 ⁇ 10 16 / cm 3 .
  • the bulk donor concentration may use the chemical concentration of the bulk donor distributed throughout the semiconductor substrate 10, and may be a value between 90% and 100% of the chemical concentration.
  • the semiconductor substrate 10 a non-doped substrate containing no dopant such as phosphorus may be used.
  • the bulk donor concentration of the non-doping substrate is, for example, 1 ⁇ 10 10 / cm 3 or more and 5 ⁇ 10 12 / cm 3 or less.
  • the bulk donor concentration of the non-doping substrate is preferably 1 ⁇ 10 11 / cm 3 or more.
  • the bulk donor concentration of the non-doping substrate is preferably 5 ⁇ 10 12 / cm 3 or less.
  • the semiconductor substrate 10 has an upper surface 21 and a lower surface 23.
  • the upper surface 21 and the lower surface 23 are two main surfaces of the semiconductor substrate 10.
  • the orthogonal axes in the plane parallel to the upper surface 21 and the lower surface 23 are the X-axis and the Y-axis
  • the axes perpendicular to the upper surface 21 and the lower surface 23 are the Z-axis.
  • Charged particles are injected into the semiconductor substrate 10 from the lower surface 23 to the second depth position Z2.
  • the charged particles are, for example, hydrogen ions, helium ions, electrons and the like.
  • the semiconductor substrate 10 of this example has an impurity chemical concentration peak 141 such as hydrogen or helium at the second depth position Z2.
  • the second depth position Z2 may be a position above the upper surface 21. That is, the charged particles may be injected so as to penetrate the semiconductor substrate 10.
  • the depth position is a position in the depth direction (Z-axis direction) of the semiconductor substrate 10.
  • the distance from the lower surface 23 to each position may be referred to as a depth position of each position.
  • the distance of the second depth position Z2 from the lower surface 23 is Z2.
  • the second depth position Z2 may be arranged on the upper surface 21 side of the semiconductor substrate 10 (that is, the region between the upper surface 21 and the central position Zc in the depth direction).
  • the average distance (also called range) that the charged particles pass through the inside of the semiconductor substrate 10 can be controlled by the acceleration energy that accelerates the charged particles.
  • the acceleration energy is set so that the average range of the charged particles is the distance Z2.
  • the average range Z2 of the charged particles may be larger than half the thickness of the semiconductor substrate 10 in the depth direction.
  • the region through which the injected charged particles have passed may be referred to as a passing region 106.
  • the passage region 106 is from the lower surface 23 of the semiconductor substrate 10 to the second depth position Z2.
  • charged particles are injected from the entire lower surface 23 of the semiconductor substrate 10.
  • charged particles may be injected into only a portion of the lower surface 23. Thereby, the passing region 106 can be locally formed on the XY plane.
  • An N-type buffer region 20 is provided on the lower surface 23 side of the semiconductor substrate 10 (that is, the region between the lower surface 23 and the central position Zc in the depth direction).
  • a lower surface region 201 is provided between the buffer region 20 and the lower surface 23.
  • the lower surface region 201 is an N-type or P-type region having a higher doping concentration than the high-concentration region 150 described later.
  • the lower surface region 201 may be a cathode region or a collector region described later.
  • the buffer region 20 suppresses the depletion layer spreading from the upper surface 21 side of the semiconductor substrate 10 reaching the lower surface region 201 (punch-through).
  • the buffer region 20 has a single first doping concentration peak 111 in which the doping concentration distribution in the depth direction of the semiconductor substrate 10 is single.
  • the first doping concentration peak 111 is located at the first depth position Z1. By providing the first doping concentration peak 111, it is possible to prevent the above-mentioned depletion layer from spreading beyond the first doping concentration peak 111 to the lower surface 23 side.
  • the buffer region 20 may include a hydrogen donor.
  • hydrogen ions such as protons are injected from the lower surface 23 to the first depth position Z1.
  • no impurity ions are locally injected between the first depth position Z1 and the second depth position Z2 other than the hydrogen ions and charged particles described above.
  • lattice defects such as single-atomic pores (V) and double-atomic pores (VV), which are mainly pores, are present. It is formed. Atoms adjacent to the vacancies have dangling bonds. Lattice defects include interstitial atoms, dislocations, etc., and in a broad sense, donors and acceptors may also be included. Sometimes referred to simply as a lattice defect. Further, the crystallinity of the semiconductor substrate 10 may be strongly disturbed due to the formation of many lattice defects by injecting charged particles into the semiconductor substrate 10. In the present specification, this disorder of crystallinity may be referred to as disorder.
  • oxygen is contained in the entire semiconductor substrate 10.
  • the oxygen is intentionally or unintentionally introduced during the manufacture of semiconductor ingots.
  • H hydrogen
  • V pores
  • O oxygen
  • the hydrogen injected into the first depth position Z1 is diffused, and the formation of VOH defects is promoted.
  • the charged particles injected into the second depth position Z2 are hydrogen ions, hydrogen is also diffused from the second depth position Z2, and the formation of VOH defects is further promoted.
  • the VOH defect functions as a donor that supplies electrons.
  • VOH defects may be referred to simply as hydrogen donors.
  • a hydrogen donor is formed in the passage region 106 of the charged particles.
  • the doping concentration of hydrogen donors is lower than the chemical concentration of hydrogen.
  • the activation rate may be a value of 0.1% to 30%. In this example, the activation rate is 1% to 5%.
  • the donor concentration in the passing region 106 of the semiconductor substrate 10 can be made higher than the bulk donor concentration.
  • the semiconductor substrate 10 having a predetermined bulk donor concentration must be prepared according to the characteristics of the element to be formed on the semiconductor substrate 10, particularly the rated voltage or the withstand voltage.
  • the donor concentration of the semiconductor substrate 10 can be adjusted by controlling the dose amounts of charged particles and hydrogen ions. Therefore, the semiconductor device 100 can be manufactured by using the semiconductor substrate 10 having a bulk donor concentration that does not correspond to the characteristics of the device or the like.
  • the dose amounts of charged particles and hydrogen ions can be controlled with relatively high accuracy. Therefore, the concentration of lattice defects generated by injecting charged particles can be controlled with high accuracy, and the concentration of hydrogen bound to lattice defects can also be controlled with high accuracy. Therefore, the donor concentration in the passage region 106 can be controlled with high accuracy.
  • the hydrogen injected into the first depth position Z1 diffuses toward the upper surface 21 to a position farther away.
  • the length of the passing region 106 in the Z-axis direction can be increased, and the doping concentration can be easily adjusted over a wide region of the semiconductor substrate 10.
  • the buffer region 20 is provided with a plurality of doping concentration peaks in order to suppress the spread of the depletion layer while suppressing the electric field concentration.
  • the doping concentration peak on the lowermost surface 23 side is set to the maximum concentration in order to prevent the depletion layer from reaching the lower surface region 201.
  • the diffusion of hydrogen injected into the maximum concentration peak of the buffer region 20 causes other doping concentration peaks. It is hindered by the lattice defect formed at the position of. Therefore, hydrogen may not diffuse over the entire passage region 106.
  • the buffer region 20 has a single first doping concentration peak 111. Therefore, hydrogen diffusion is not suppressed at least in the buffer region 20. Therefore, the hydrogen injected into the first depth position Z1 is likely to diffuse toward the upper surface 21.
  • Figure 2 shows in the position shown in line A-A of FIG. 1, the lattice defect density D V in the depth direction of hydrogen chemical concentration C H, each distribution of the doping concentration D d and the impurity chemical concentration C I ..
  • the impurities in this example are helium or hydrogen.
  • the horizontal axis of FIG. 2 shows the depth position from the lower surface 23, and the vertical axis shows the hydrogen chemical concentration, the donor concentration, and the impurity chemical concentration per unit volume on the logarithmic axis.
  • the lattice defect density DV is the distribution before annealing, and the other concentrations show the distribution after injecting hydrogen ions and charged particles (impurities) and annealing.
  • the hydrogen chemical concentration and the impurity chemical concentration in FIG. 2 are measured by, for example, the SIMS method.
  • the doping concentration in FIG. 2 is an electrically activated doping concentration measured by, for example, the CV method or the SR method.
  • Hydrogen chemical concentration C H of the present embodiment includes a hydrogen chemical concentration peak 131 to a first depth position Z1.
  • the hydrogen chemical concentration peak 131 shows a maximum value at the first depth position Z1.
  • Impurity chemical concentration C I of the present example has an impurity chemical concentration peak 141 to a second depth position Z2.
  • the impurity chemical concentration peak 141 shows a maximum value at the second depth position Z2.
  • the doping concentration D d has a first doping concentration peak 111 and a second doping concentration peak 121. Further, the doping concentration D d may have a doping concentration peak in the lower surface region 201.
  • the lower surface region 201 of this example has a P-type doping concentration peak.
  • a P-type dopant such as boron may be injected into the lower surface region 201.
  • the lower surface region 201 may have an N-type doping concentration peak. In this case, an N-type dopant such as phosphorus may be injected into the lower surface region 201.
  • the first doping concentration peak 111 of this example is a hydrogen donor in which a lattice defect due to hydrogen ion injection into the first depth position Z1 and hydrogen injected into the first depth position Z1 are bonded. This is the concentration peak of (VOH defect). Therefore, the first doping concentration peak 111 shows a maximum value at the first depth position Z1.
  • the second doping concentration peak 121 is a concentration peak of a hydrogen donor in which a lattice defect due to injection of charged particles into the second depth position Z2 and hydrogen diffused from the first depth position Z1 are bonded. .. Therefore, the second doping concentration peak 121 shows a maximum value at the second depth position Z2.
  • the position where the first doping concentration peak 111 shows the maximum value does not have to exactly coincide with the first depth position Z1. For example, if the position where the first doping concentration peak 111 shows the maximum value is included in the range of the full width at half maximum of the first hydrogen chemical concentration peak 131 with respect to the first depth position Z1, the first It may be assumed that the doping concentration peak 111 of 1 is substantially located at the first depth position Z1. Similarly, if the position where the second doping concentration peak 121 shows the maximum value is included in the range of the full width at half maximum of the impurity chemical concentration peak 141 with respect to the second depth position Z2, the second It may be assumed that the doping concentration peak 121 is substantially located at the second depth position Z2.
  • the doping concentration may be the first doping concentration peak 111.
  • Each concentration peak has a lower hem in which the concentration decreases from the apex to the lower surface 23 and an upper hem in which the concentration decreases from the apex to the upper surface 21.
  • the hydrogen chemical concentration peak 131 has a lower hem 132 and an upper hem 133.
  • the impurity chemical concentration peak 141 has a lower hem 142 and an upper hem 143.
  • the first doping concentration peak 111 has a lower hem 112 and an upper hem 113.
  • the second doping concentration peak 121 has a lower hem 122 and an upper hem 123.
  • the concentration may decrease sharply in the upper hem than in the lower hem. Further, since the doping concentration depends on the hydrogen chemical concentration or the impurity chemical concentration, the concentration may decrease sharply in the upper hem than in the lower hem at each doping concentration peak.
  • lattice defect concentration D V is the first depth position Z1 having a first defect density peak 211, a second defect density peak 212 to a second depth position Z2. Further, charged particles passed through the passing region 106 (see FIG. 1) from the second depth position Z2 to the lower surface 23, except for the vicinity of the first depth position Z1 and the second depth position Z2. The resulting lattice defects are formed at a nearly uniform density. As shown by the dotted line in the distribution diagram of the lattice defect density D V of FIG.
  • the lattice defect concentration D V is within a range that does not exceed the peak 212 may be increased gradually toward the peak 212. Even when such lattice defect concentration D V increases toward the peak 212, lattice defects caused by the charged particles are passed may be a formed in a substantially uniform density.
  • the hydrogen injected into the first depth position Z1 diffuses toward the upper surface 21 by the annealing treatment.
  • the buffer region 20 has a single first doping concentration peak 111. Therefore, there are no defect density peaks other than the first defect density peak 211 in the buffer region 20. Therefore, hydrogen is likely to diffuse from the first depth position Z1 to the second depth position Z2.
  • a VOH defect hydrogen donor
  • the high concentration region 150 is a region where the donor concentration is higher than the bulk donor concentration D b.
  • the high concentration region 150 is arranged between the buffer region 20 and the upper surface 21 of the semiconductor substrate 10.
  • the high concentration region 150 may be a region having a substantially uniform doping concentration in the depth direction.
  • the fact that the doping concentration is almost uniform in the depth direction means that, for example, a region in which the difference between the maximum value and the minimum value of the doping concentration is within 50% of the maximum value of the doping concentration is continuous in the depth direction. May point to.
  • the difference may be 30% or less of the maximum value of the doping concentration in the region, and may be 10% or less.
  • the value of the doping concentration distribution may be within ⁇ 50% of the average concentration of the doping concentration distribution, and may be within ⁇ 30% with respect to the average concentration of the doping concentration distribution in a predetermined range in the depth direction. Well, it may be within ⁇ 10%.
  • the predetermined range W in the depth direction may be as follows as an example. That is, the length from the first depth position Z1 to the second depth position Z2 is Z L , and from the center Z 12 c between Z1 and Z2, the first depth position Z1 side and the second The range may be a section having a length of 0.5 Z L between two points separated by 0.25 Z L on the depth position Z 2 side of the above.
  • the length of the predetermined range may be a 0.75Z L, may be a 0.3Z L, it may be 0.9Z L.
  • the end position on the upper surface 21 side of the buffer region 20 may be a depth position where a substantially uniform doping concentration in the high concentration region 150 begins to monotonically increase toward the first doping concentration peak 111. ..
  • the measurement result of the distribution of the doping concentration D d may include a minute peak due to noise or the like during measurement even in the region where the dopant is not injected.
  • the peak A in doping concentration D d, the ratio between the minimum and maximum values of the doping concentration D d in the length within 10 ⁇ m may refer to what is 1.1 times or more.
  • the ratio may be 1.2 times or more, and may be 1.5 times or more.
  • the peak of each chemical concentration may also refer to one having the ratio.
  • the high concentration region 150 may be continuously provided from the first doping concentration peak 111 to the impurity chemical concentration peak 141.
  • the high concentration region 150 may be continuously provided from the upper end of the buffer region 20 to the second depth position Z2.
  • the length of the high concentration region 150 in the depth direction may be 50% or more, 60% or more, 70% or more, 80% or more of the thickness of the semiconductor substrate 10 in the depth direction. It may be.
  • the length of the high concentration region 150 in the depth direction may be 70 ⁇ m or more, 80 ⁇ m or more, 90 ⁇ m or more, or 100 ⁇ m or more.
  • the range in which the high concentration region 150 is formed can be easily defined by the second depth position Z2.
  • the minimum value of the donor concentration in the high concentration region 150 is higher than the bulk donor concentration D b of the semiconductor substrate 10. That is, the donor concentration of the high concentration region 150 (or doping concentration) throughout the high-concentration region 150 is higher than the bulk donor concentration D b.
  • the donor concentration in the high concentration region 150 is determined by the sum of the bulk donor concentration and the hydrogen donor concentration (VOH defect concentration).
  • the hydrogen donor concentration can be accurately controlled by the dose amount of the charged particles with respect to the second depth position Z2 and the dose amount of hydrogen ions with respect to the first depth position Z1. Therefore, by sufficiently increasing the hydrogen donor concentration as compared with the bulk donor concentration, it is possible to reduce the variation in the donor concentration in the high concentration region 150 even when the bulk donor concentration varies.
  • the donor concentration in the high concentration region 150 may be 2 times or more, 5 times or more, or 10 times or more the bulk donor concentration D b.
  • Figure 3 shows the lattice defect density D V of the comparative example, the hydrogen chemical concentration C H, each distribution of the doping concentration D d and the impurity chemical concentration C I.
  • the semiconductor device of the comparative example has one or more doping concentration peaks 117 on the upper surface 21 side of the first doping concentration peak 111 in the buffer region 20. Each doping concentration peak 117 is formed by injecting hydrogen ions as an example.
  • Hydrogen chemical concentration C H of this example the same depth position and each of the doping concentration peaks 117, having a hydrogen chemical concentration peak 137.
  • the lattice defect density D V is the same depth position and each of the hydrogen chemical concentration peaks 137 has a defect density peak 213. That is, the buffer region 20 has one or more defect density peaks 213 on the upper surface 21 side of the first depth position Z1.
  • the hydrogen chemical concentration peak 131 is 10 times or more higher than the other hydrogen chemical concentration peaks 137. Therefore, most of the hydrogen diffused from the buffer region 20 to the upper surface 21 side is the hydrogen injected into the first depth position Z1. However, the diffusion of hydrogen injected into the first depth position Z1 is hindered by the defect density peak 213. For example, hydrogen binds to lattice defects, or the presence of lattice defects impedes hydrogen transfer.
  • the high concentration region 150 is not formed up to the second depth position Z2, and the low concentration region 181 with a low donor concentration remains.
  • the donor concentration in the low concentration region 181 may be comparable to the bulk donor concentration D b.
  • the carrier concentration in the low concentration region 181 may be lower than the bulk donor concentration D b. Since almost no hydrogen donor is formed in the low concentration region 181, the donor concentration in the low concentration region 181 is greatly affected by the bulk donor concentration. Therefore, the donor concentration in the low concentration region 181 has a relatively large variation.
  • the semiconductor device 100 shown in FIG. 2 since the high concentration region 150 can be formed widely, the variation in the doping concentration can be suppressed, and the characteristics of the semiconductor device 100 can be adjusted accurately.
  • the high-concentration first doping concentration peak 111 can be arranged in the vicinity of the lower surface 23 to suppress the decrease in the avalanche tolerance, and the high-concentration region 150 can be formed up to the vicinity of the upper surface 21. ..
  • the distance between the first depth position Z1 and the lower surface 23 may be 5 ⁇ m or less, and may be 3 ⁇ m or less.
  • FIG. 4 is a flowchart showing an example of a manufacturing method of the semiconductor device 100.
  • the structure on the upper surface 21 side of the semiconductor substrate 10 is formed.
  • the structure on the upper surface 21 side includes at least a part of a gate trench, a dummy trench, an emitter region, a base region, a storage region, an interlayer insulating film, an emitter electrode, and a gate wiring, which will be described later.
  • all these structures may be formed.
  • the lower surface 23 side of the semiconductor substrate 10 is ground to adjust the thickness of the semiconductor substrate 10.
  • the thickness of the semiconductor substrate 10 may be adjusted according to the withstand voltage that the semiconductor device 100 should have.
  • the lower surface region 201 is formed in the region in contact with the lower surface 23 of the semiconductor substrate 10.
  • the lower surface region 201 may be formed by injecting an N-type dopant or a P-type dopant from the lower surface 23 and locally annealing the vicinity of the lower surface 23 with a laser or the like.
  • the first injection step S406 includes a charged particle injection step S408 and a hydrogen injection step S410.
  • charged particles are injected from the lower surface 23 of the semiconductor substrate 10 to the second depth position Z2.
  • the charged particles may be hydrogen ions, helium ions, or electron beams.
  • hydrogen ions are injected from the lower surface 23 of the semiconductor substrate 10 into the first depth position Z1.
  • hydrogen ions are injected into the first position Z1 so that the hydrogen chemical concentration distribution has a single peak in the region on the lower surface 23 side of the second depth position Z2.
  • a peak of hydrogen chemical concentration may exist at the second depth position Z2. Either the charged particle injection step S408 or the hydrogen injection step S410 may be performed first.
  • the semiconductor substrate 10 is annealed.
  • the semiconductor substrate 10 is put into an annealing furnace to anneal the entire semiconductor substrate 10.
  • a high concentration region 150 is formed between the first depth position Z1 and the second depth position Z2.
  • the annealing step S412 is preferably performed under the condition that the hydrogen injected into the first depth position Z1 can be diffused to the second depth position Z2.
  • the annealing temperature in the annealing step S412 is 350 ° C. or higher and 400 ° C. or lower.
  • the annealing temperature may be 360 ° C. or higher and may be 380 ° C. or lower.
  • the annealing time in the annealing step S412 may be 30 minutes or more, 1 hour or more, or 3 hours or more.
  • the annealing time may be 10 hours or less, and may be 7 hours or less.
  • a metal electrode is formed on the lower surface 23 of the semiconductor substrate 10.
  • the metal electrode may be a collector electrode described later. Further, even if an impurity such as helium is injected into the semiconductor substrate 10 between the annealing step S412 and the lower surface side electrode forming step S414, lattice defects are locally formed and the carrier lifetime is adjusted. good.
  • FIG. 5 is a flowchart showing another example of the manufacturing method of the semiconductor device 100.
  • the manufacturing method of this example differs from the example shown in FIG. 4 in that it further includes a grinding step S500, a second injection step S502, and a second annealing step S504.
  • Other steps may be similar to the example shown in FIG.
  • the lower surface region forming step S404 is not performed before the first injection step S406.
  • the lower surface 23 side of the semiconductor substrate 10 is ground in the grinding step S500.
  • the lower surface 23 is ground so as to remove the region including the first depth position Z1 from the semiconductor substrate 10.
  • a part of the upper hem 113 of the first doping concentration peak 111 may be ground so as to remain on the semiconductor substrate 10, and the upper hem 113 may be ground so as not to remain on the semiconductor substrate 10. .
  • the semiconductor substrate 10 may be ground so that the high concentration region 150 is exposed on the lower surface 23.
  • the thickness of the semiconductor substrate 10 ground by the grinding step S402 and the grinding step S500 is a thickness corresponding to a predetermined withstand voltage.
  • the grinding amount in the grinding step S402 and the grinding step S500 may be arbitrarily set. Grinding step S402 may be omitted.
  • the lower surface region forming step S404 the lower surface region 201 is formed.
  • the N-type dopant is injected into the third depth position Z3.
  • the third depth position Z3 is a position where the buffer region 20 should be formed.
  • the N-type dopant may be hydrogen or may be a dopant other than hydrogen such as phosphorus.
  • the semiconductor substrate 10 is annealed.
  • the N-type dopant injected into the third depth position Z3 is activated to become a donor.
  • the buffer area 20 can be formed.
  • the entire semiconductor substrate 10 may be annealed, or may be locally annealed.
  • a metal electrode is formed on the lower surface 23 of the semiconductor substrate 10.
  • FIG. 6 is a diagram illustrating a semiconductor device 100 according to the manufacturing method of FIG.
  • the lower surface of the semiconductor substrate 10 before being ground by the grinding step S500 is the lower surface 23-2, and the lower surface after grinding is the lower surface 23-1.
  • first injection step S406 hydrogen ions are injected from the lower surface 23-2 to the first depth position Z1, and charged particles are injected from the lower surface 23-2 to the second depth position Z2. Further, the hydrogen injected into the first depth position Z1 is diffused by the first annealing step S412.
  • the lower surface 23-2 is ground to remove the region including the first depth position Z1.
  • the lower surface region forming step S404 the lower surface region 201 is formed in the region in contact with the lower surface 23-1.
  • the N-type dopant is injected into the third depth position Z3 by the second injection step S502.
  • the semiconductor substrate 10 is annealed in the second annealing step S504 to activate the N-type dopant injected into the third depth position Z3 to form the buffer region 20.
  • Figure 7 shows in the position shown in line A-A of FIG. 6, the lattice defect density D V in the depth direction of hydrogen chemical concentration C H, each distribution of the doping concentration D d and the impurity chemical concentration C I ..
  • the impurities in this example are helium or hydrogen.
  • the lattice defect density D V the lattice formed when the hydrogen ion implantation or the like first depth position Z1, the second depth position Z2, the third depth position Z3 It shows the defect density. That is, the lattice defect density D V, the lattice defects formed when forming the lower surface region 201 is omitted.
  • the lattice defect density D V the lattice defects formed when forming the lower surface region 201 is omitted.
  • the lattice defect concentration D V is within a range that does not exceed the peak 212 may be increased gradually toward the peak 212.
  • the mode in which the lattice defect density DV is increasing is shown by a dotted line. Even when such lattice defect concentration D V increases toward the peak 212, lattice defects caused by the charged particles are passed may be a formed in a substantially uniform density. It also shows the density including lattice defects that have become hydrogen donors by annealing. Concentrations other than the lattice defect density indicate the distribution after the second annealing step S504.
  • a high concentration of hydrogen is injected into the first depth position Z1 in order to diffuse hydrogen to the second depth position Z2. Therefore, at the first depth position Z1, a hydrogen donor having a concentration higher than that of the hydrogen donor that the buffer region 20 should have may be formed.
  • the region including the first depth position Z1 is ground by the grinding step S500.
  • the N-type dopant having the concentration that the buffer region 20 should have is injected into the third depth position Z3.
  • a defect density peak 214 is formed at the third depth position Z3 by injecting an N-type dopant.
  • the defect density peak 214 is formed after the first annealing step S412, it does not interfere with the diffusion of hydrogen injected into the first depth position Z1.
  • the hydrogen chemical concentration peak 131 at the first depth position Z1 is removed.
  • the hydrogen chemical concentration CH gradually decreases from the lower surface 23 toward the second depth position Z2.
  • the first doping concentration peak 111 is a concentration peak of an N-type dopant other than the hydrogen donor.
  • hydrogen may be injected into the third depth position Z3.
  • the first doping concentration peak 111 is the concentration peak of the hydrogen donor.
  • the hydrogen chemical concentration C H has a chemical concentration peak (not shown) to a first depth position Z1.
  • FIG. 8 is a diagram showing another example of the first doping concentration peak 111.
  • the first doping concentration peak 111 of this example may be applied to each of the examples described in FIGS. 1 to 7.
  • the first doping concentration peak 111 of this example is a concentration peak containing both a hydrogen donor and an N-type dopant other than the hydrogen donor.
  • the N-type dopant is phosphorus.
  • the N-type dopant is selenium or arsenic.
  • FIG. 8 shows the phosphate chemical concentration C P with a broken line.
  • Phosphorus chemical concentration C P has the chemical concentration peak 119 to a first depth position Z1.
  • phosphorus doping concentration D P is the concentration of the donor of activated by a one-dot chain line.
  • Doping concentration D P is the concentration multiplied by the activation rate of phosphorus to the phosphorus chemical concentration C P.
  • the activation rate of phosphorus may be 1.
  • the doping concentration D P it may be used phosphorus chemical concentration C P.
  • Doping concentration D1 of the first doping concentration peak 111 is substantially equal to the doping concentration D P corresponding to the phosphorus chemical concentration C P, and the density D H of hydrogen donor, the sum of the bulk donor concentration D b.
  • Hydrogen may be injected into the semiconductor substrate 10 at the first depth position Z1.
  • the hydrogen chemical concentration C H has a peak in the first depth position Z1.
  • the hydrogen chemical concentration C H may not have a peak at a first depth position Z1.
  • the first doping concentration peak 111 may include a hydrogen donor formed by diffusing hydrogen injected into the ground region as shown in FIG. 7.
  • the injection of an N-type dopant such as phosphorus may be performed after the injection of hydrogen ions.
  • FIG. 9A is a diagram illustrating the relationship between the hydrogen chemical concentration peak 131 and the first doping concentration peak 111.
  • the slope 134 of the lower hem 132 of the hydrogen chemical concentration peak 131 is used to normalize the slope 114 of the lower hem 112 of the first doping concentration peak 111.
  • the standardization is, for example, a process of dividing the slope 114 by the slope 134.
  • the inclination of the lower hem may be the inclination between the position where the concentration shows the maximum value and the position where the concentration is a predetermined ratio to the maximum value.
  • the predetermined ratio may be 80%, 50%, 10%, 1%, or any other ratio may be used.
  • the slope of the concentration distribution between the first depth position Z1 and the lower surface 23 of the semiconductor substrate 10 may be used.
  • the slope 134 of the hydrogen chemical concentration peak 131 is given by (H1-aH1) / (Z1-Z4), and the slope 114 of the first doping concentration peak 111 is (D1-aD1) / (. It is given by Z1-Z5).
  • H1 is the hydrogen chemical concentration at the first depth position Z1
  • D1 is the doping concentration at the first depth position Z1
  • a is a predetermined ratio
  • Z4 is below the hydrogen chemical concentration peak 131.
  • Z5 is the depth at which the hydrogen concentration becomes aH1 at the side hem 132
  • Z5 is the depth at which the doping concentration becomes aD1 at the lower hem 112 at the first doping concentration peak 111.
  • the slope 114 when the slope 114 is standardized with the slope 134, it becomes (D1-aD1) (Z1-Z4) / ⁇ (H1-aH1) (Z1-Z5) ⁇ .
  • ⁇ be the slope obtained by normalizing the slope 114 with the slope 134.
  • FIG. 9B is a diagram illustrating the relationship between the impurity chemical concentration peak 141 and the second doping concentration peak 121.
  • hydrogen ions are injected as charged particles at the second depth position Z2.
  • the slope 144 of the lower hem 142 of the impurity chemical concentration peak 141 is used to normalize the slope 124 of the lower hem 142 of the second doping concentration peak 121.
  • the slope 144 of the impurity chemical concentration peak 141 is given by (H2-aH2) / (Z2-Z6), and the slope 124 of the second doping concentration peak 121 is (D2-aD2) / (Z2). -Z7) is given.
  • H2 is the hydrogen chemical concentration at the second depth position Z2
  • D2 is the doping concentration at the second depth position Z2
  • a is a predetermined ratio
  • Z6 is below the impurity chemical concentration peak 141.
  • Z7 is the depth at which the hydrogen chemical concentration is aH2 at the side hem 142
  • Z7 is the depth at which the doping concentration is aD2 at the lower hem 122 at the second doping concentration peak 121.
  • the ratio a used to normalize the slope of the second doping concentration peak 121 may be the same as or different from the ratio a used to normalize the slope of the first doping concentration peak 111. ..
  • the slope 124 when the slope 124 is standardized with the slope 144, it becomes (D2-aD2) (Z2-Z6) / ⁇ (Z2-Z7) (H2-aH2) ⁇ .
  • ⁇ be the slope obtained by normalizing the slope 124 with the slope 144.
  • the normalized slope ⁇ of the lower hem 122 of the second doping concentration peak 121 is smaller than the normalized slope ⁇ of the lower hem 112 of the first doping concentration peak 111. That is, the second doping concentration peak 121 has a gentler peak with respect to the peak of the hydrogen chemical concentration than the first doping concentration peak 111. By injecting hydrogen ions so that such a second doping concentration peak 121 is formed, a high concentration region 150 having a flat concentration distribution can be formed. Further, by forming the second doping concentration peak 121 into a gentle shape, it is possible to moderate the change in the doping concentration at the tip of the high concentration region 150.
  • the normalized slope ⁇ of the lower hem 122 of the second doping concentration peak 121 may be less than or equal to 1 times the normalized slope ⁇ of the lower hem of the first doping concentration peak 111. It may be 1 times or less, and may be 0.01 times or less.
  • the inclination 144 of the lower hem 142 of the impurity chemical concentration peak 141 may be smaller than the inclination 145 of the upper hem 143.
  • the chemical concentration distribution of hydrogen injected deep from the lower surface 23 may draw a gentle hem toward the lower surface 23, so by comparing the inclination 144 of the lower hem 142 with the inclination 145 of the upper hem 143. , It may be possible to determine whether or not the hydrogen injected into the second depth position Z2 is injected from the lower surface 23 side.
  • the slope 145 is given by (H2-aH2) / (Z8-Z2).
  • the slope 125 is given by (D2-aD2) / (Z9-Z2).
  • Z8 is the depth at which the hydrogen chemical concentration is aH2 at the upper hem 143 of the impurity chemical concentration peak 141
  • Z9 is the depth at which the doping concentration is aD2 at the upper hem 123 of the second doping concentration peak 121.
  • the slope 124 of the lower hem 122 of the second doping concentration peak 121 is larger than the slope 125 of the upper hem 123, but the second doping concentration peak 121 is similar to the impurity chemical concentration peak 141.
  • the inclination 124 of the lower hem 122 may be smaller than the inclination 125 of the upper hem 123.
  • FIG. 9C is a diagram illustrating the inclination of the lower hem 142.
  • the inclination of the lower hem 142 may be considered as follows.
  • the width (10% total width) between the two positions P10 and P11 having a concentration of 10% (0.1 ⁇ H2) of the peak concentration H2 is set. , FW 10% M.
  • the two positions P10 and P11 are the two positions closest to the second depth position Z2 among the points where the hydrogen chemical concentration is 0.1 ⁇ H2 with the second depth position Z2 in between.
  • the position on the hydrogen chemical concentration peak 131 side is designated as Z10.
  • the slope of the doping concentration at position Z10 is almost flat.
  • the slope of the hydrogen chemical concentration at position Z10 is more than 100 times the slope of the doping concentration at position Z10.
  • the slope of the hydrogen chemical concentration at position Z10 may be 100 times or more, or 1000 times or more, the slope of the doping concentration at position Z10.
  • FIG. 10A is a diagram illustrating another definition of normalization of the inclination of the lower hem 112.
  • the position Z4 is a predetermined position here.
  • Position Z4 is hydrogen chemical concentration C H and doping concentration D d is as long as it is a position that is the lower side skirt 132,112 at the lower surface 23 side than the first depth position Z1. Let the hydrogen chemical concentration at position Z4 be a ⁇ H1 and the doping concentration be b ⁇ D1.
  • a is the ratio of the hydrogen chemical concentration at the position Z4 to the concentration H1 of the hydrogen chemical concentration peak 131 at the first depth position Z1.
  • b is the ratio of the doping concentration at position Z3 to the concentration D1 at the first doping concentration peak 111 at the first depth position Z1.
  • the slope ratio ⁇ that standardizes the ratio of the slopes of the hydrogen chemical concentration and the doping concentration in the sections Z4 to Z1 and the ratio of the slopes is introduced.
  • the ratio of the slopes of the hydrogen chemical concentration in the sections Z4 to Z1 is defined as (H1 / aH1) / (Z1-Z4).
  • the ratio of the slopes of the donor concentration in the sections Z4 to Z1 is defined as (D1 / bD1) / (Z1-Z4).
  • the slope ratio ⁇ which is the ratio of the slopes of the hydrogen chemical concentration in the sections Z4 to Z1, and the ratio of the slopes of the doping concentration is standardized, is set to ⁇ (D1 / bD1) / (Z1-Z4) ⁇ / ⁇ (H1 / aH1). ) / (Z1-Z4) ⁇ .
  • the normalized slope ratio ⁇ becomes a simple ratio a / b by calculating the above equation.
  • FIG. 10B is a diagram illustrating another definition of standardization of the inclination of the lower hem 122.
  • an index ⁇ similar to the index ⁇ is introduced.
  • the position Z6 is a predetermined position here.
  • the position Z6 may be a position where the hydrogen chemical concentration and the doping concentration are lower hem 142 and 122 on the lower surface 23 side than the second depth position Z2. Let the hydrogen chemical concentration at position Z6 be c ⁇ H2 and the doping concentration be d ⁇ D2.
  • c is the ratio of the hydrogen chemical concentration at the position Z6 to the hydrogen chemical concentration H2 at the second depth position Z2.
  • d is the ratio of the doping concentration at position Z6 to the concentration D2 at the second doping concentration peak 121 at the second depth position Z2.
  • the slope ratio ⁇ that standardizes the slope ratios of the hydrogen chemical concentration and the doping concentration in the sections Z6 to Z2 and the slope ratio is introduced.
  • the ratio of the slopes of the hydrogen chemical concentration in the sections Z6 to Z2 is defined as (H2 / cH2) / (Z2-Z6).
  • the ratio of the slopes of the doping concentration in the sections Z6 to Z2 is defined as (D2 / dD2) / (Z2-Z6).
  • the slope ratio ⁇ which is the ratio of the slopes of the hydrogen chemical concentration in the sections Z6 to Z2 and the ratio of the slopes of the doping concentration is standardized, is set to ⁇ (D2 / dD2) / (Z2-Z6) ⁇ / ⁇ (H2 / cH2). ) / (Z2-Z6) ⁇ .
  • the normalized slope ratio ⁇ becomes a simple ratio (c / d) by calculating the above equation.
  • the hydrogen chemical concentration distribution and the doping concentration distribution often have similar figures.
  • the similar figure means that the doping concentration distribution reflects the hydrogen chemical concentration distribution, for example, when the horizontal axis is the depth and the vertical axis is the common logarithm of the concentration. That is, in the predetermined sections Z4 to Z1, hydrogen ions are implanted and further annealed, so that the doping concentration distribution reflects the hydrogen chemical concentration distribution.
  • H1 of the hydrogen chemical concentration peak 131 is 1 ⁇ 10 17 at réellems / cm 3 and the hydrogen chemical concentration aH1 at position Z4 is 2 ⁇ 10 16 at réellems / cm 3
  • a is 0.2.
  • the normalized slope ratio ⁇ is 1 because it is a / b. That is, at the first depth position Z1 near the lower surface 23, the ratio a of the slope of the hydrogen chemical concentration distribution and the ratio b of the slope of the doping concentration distribution are almost the same value, and it can be said that they are similar figures.
  • the hydrogen chemical concentration distribution and the doping concentration distribution do not have to be similar figures. That is, in the predetermined sections Z6 to Z2, the doping concentration distribution does not have to reflect the hydrogen chemical concentration distribution.
  • the hydrogen chemical concentration H2 of the impurity chemical concentration peak 141 is 1 ⁇ 10 16 at réellems / cm 3
  • the hydrogen chemical concentration cH2 at position Z6 is 1 ⁇ 10 15 at réellems / cm 3
  • c is 0.1. ..
  • the normalized slope ratio ⁇ is 0.2 because it is c / d. That is, at the second depth position Z2 sufficiently deep from the lower surface 23, the ratio c of the slope of the hydrogen chemical concentration distribution is 0.2 times smaller than the ratio d of the slope of the doping concentration distribution, which is far from the similarity. It can be said to show the shape.
  • the standardized slope ratio ⁇ may be larger than the standardized slope ratio ⁇ .
  • the slope ratio ⁇ may be 1.1 or more, 1.5 or more, and 2 or more. Alternatively, it may be 10 or more, and may be 100 or more.
  • the actual positions of the hydrogen chemical concentration peak 131 and the impurity chemical concentration peak 141 may differ from the actual positions of the first doping concentration peak 111 and the second doping concentration peak 121.
  • the position of the chemical concentration peak and the position of the doping concentration do not match in this way, the position of the chemical concentration peak is set to the first depth position Z1 or the second depth position Z2, and the doping concentration is the first depth.
  • the concentration at the vertical position Z1 or the second depth position Z2 may be used as the peak position for convenience. This makes it possible to calculate according to the above definition.
  • 11 to 19 are diagrams illustrating an example of a method of determining the bulk donor concentration and the preferred range of donor concentration in the high concentration region 150.
  • the bulk donor concentration and the donor concentration are set so that the final donor concentration (doping concentration) in the high concentration region 150 becomes a relatively stable concentration even when the bulk donor concentration varies. ..
  • the bulk donor concentration specification value is a specification value specified by the semiconductor wafer manufacturer. If the specification value has a range, the median value of the specification value may be used.
  • the concentration of hydrogen donor (VOH defect) be NH .
  • the variation in hydrogen donor concentration NH is negligibly small compared to the variation in bulk donor concentration.
  • the variation of the hydrogen donor concentration NH is set to 0.
  • the target value of the final donor concentration be NF0 .
  • the final donor concentration actually obtained is defined as N Fre .
  • the above-mentioned concentrations are all concentrations per unit volume (/ cm 3 ).
  • Target value N F0 final donor concentration the specification value N B0 bulk donor concentration, since the result of the addition of hydrogen donor concentration N H, is given by the following equation.
  • N F0 N H + N B0 ... Equation (1)
  • the actual donor concentration N Fre is obtained by adding the hydrogen donor concentration NH to the actual bulk donor concentration N Bre , and is therefore given by the following equation.
  • N Fre N H + N Bre ... Equation (2)
  • the parameter ⁇ is the ratio of the actual bulk donor concentration N Bre and the specification value N B0, and indicates that the actual bulk donor concentration N Bre deviates from the specification value N B0 as the distance from 1 increases.
  • the parameter ⁇ is the ratio of the actual donor concentration N Fre and the target value N F0, and indicates that the actual donor concentration N Fre deviates from the target value N F 0 as the distance from 1 increases. That is, if ⁇ is sufficiently close to 1, even if the actual bulk donor concentration N Bre deviates by ⁇ times from the specification value N B 0 , the actual donor concentration N Fre becomes the target value almost independently of ⁇ . It shows that it is almost the same as NF0.
  • the specific resistance variation of the silicon wafer manufactured by the FZ method in which the variation of the bulk donor concentration is relatively small is generally as follows.
  • the actual donor concentration N Fre is affected by the variability ( ⁇ ) of the actual bulk donor concentration N Bre.
  • the variation in the hydrogen donor concentration NH can be regarded as almost 0 as compared with the variation in the bulk donor concentration N Bre. Therefore, by reducing the specifications N B0 Bulk donor concentration to the target value N F0 donor concentration, it is possible to reduce the proportion of the component which varies in the donor concentration N Fre.
  • Parameter epsilon ' is the target value N F0 donor concentration
  • the specification value N B0 Bulk donor concentration epsilon' is set to be smaller by a parameter meaning. If ⁇ 'is set to a value smaller than 1 in the range where it does not become 0, it is examined whether ⁇ approaches 1 sufficiently without depending on ⁇ .
  • N B0 N F0 / ⁇ ⁇ ⁇ Equation (7)
  • N Fre (1-1 / ⁇ ) N F0 + ⁇ N B0 ... Equation (9)
  • Eq. (7) into Eq. (9), the following equation is obtained.
  • ⁇ 1 + ⁇ '( ⁇ -1) ⁇ ⁇ ⁇ Equation (12)
  • FIG. 11 is a graph showing the relationship between ⁇ 'and ⁇ represented by the equation (12) for each ⁇ .
  • ⁇ indicates the ratio of the actual donor concentration N Fre to the target value N F0
  • ⁇ indicates the ratio of the actual bulk donor concentration N Bre to the specified value N B 0 .
  • the permissible value of ⁇ is 0.85 or more and 1.15 or less.
  • the specification value N B0 bulk donor concentration 0.5 times the target value N F0 donor concentration or less, that, the epsilon 'and 0.5 or less.
  • ⁇ is 1.15 or less, which is within the permissible range.
  • the actual donor concentration N Fre is 1.15 times or less of the target value N F0.
  • ⁇ is 0.7, if ⁇ 'is 0.5 or less, ⁇ is within the permissible range.
  • ⁇ 'approaches 0, ⁇ converges to 1. For example, in the case of ⁇ 2, if ⁇ 'is approximately 0.2 or less, ⁇ is within the permissible range.
  • ranges A to D can be considered as a preferable range of ⁇ '.
  • ⁇ 'is 0.5 and ⁇ is within the range of 0.7 to 1.3, ⁇ is within the permissible range.
  • the specification value N B0 of the bulk donor concentration is 1 ⁇ 10 14 / cm 3 and ⁇ 'is 0.001
  • the target value N F0 of the donor concentration is 1 ⁇ 10 11 / cm 3 and is about 46000 ⁇ cm.
  • the specification value N B0 of the bulk donor concentration is 1 ⁇ 10 14 / cm 3 and ⁇ 'is 0.001
  • the target value N F0 of the donor concentration is 1 ⁇ 10 11 / cm 3 and is about 46000 ⁇ cm.
  • ⁇ ' is preferably 0.1 or less, and more preferably 0.02 or less.
  • ranges E to H can be considered.
  • ⁇ 'is 0.1 and ⁇ is in the range of approximately 0.05 (not shown) to 3.0, ⁇ is sufficiently within the permissible range.
  • N B0 Bulk donor concentration is that 1 ⁇ 10 14 / cm 3, if epsilon 'is 0.1, the target value N F0 donor concentration is 1 ⁇ 10 13 / cm 3, about 460 ⁇ cm Corresponds to.
  • the actual donor concentration N Fre corresponds to the donor concentration in the high concentration region 150.
  • the withstand voltage of the semiconductor device 100 is almost determined by the donor concentration in the high concentration region 150, which occupies a large region in the semiconductor substrate 10. Therefore, the rated voltage of the semiconductor device 100 determines a preferable range of the donor concentration N Fre in the high concentration region 150.
  • range of bulk donor concentration N Bre to the donor concentration N Fre can be stabilized is determined.
  • FIG. 12 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre.
  • the donor concentration N Fre (/ cm 3 ) at the center Zc in the depth direction of the semiconductor substrate 10 is (9.2245 ⁇ 10 15 ) / x or more and (9.2245 ⁇ 10 16 ) / x. be.
  • x is the rated voltage (V).
  • the donor concentration N Fre (/ cm 3 ) was determined by referring to the doping concentration in the drift region of a general semiconductor substrate formed by the FZ method, but the doping concentration in the drift region of the semiconductor substrate formed by the MCZ method was determined. You may decide by referring to.
  • the upper limit 311 and the lower limit 312 of the preferable range of the donor concentration N Fre (/ cm 3) are shown by broken lines.
  • the upper limit 313 and the lower limit 314 of the preferable range of the bulk donor concentration N Bre in the above-mentioned range A ( ⁇ 'is 0.001 or more and 0.5 or less) are shown by solid lines.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.5) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.001) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • the unit of the upper limit 313 and the lower limit 314 in each example is (/ cm 3 ).
  • x is the rated voltage (V).
  • FIG. 13 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is in the range B (0.01 or more and 0.333 or less).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.333) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.01) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • FIG. 14 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is in the range C (0.03 or more and 0.25 or less).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.25) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.03) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • FIG. 15 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is in the range D (0.1 or more and 0.2 or less).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.2) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.1) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • FIG. 16 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is in the range E (0.001 or more and 0.1 or less).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.1) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.001) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • FIG. 17 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is in the range F (0.002 or more and 0.05 or less).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.05) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.002) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • -Lower limit 314 (1.84049 x 10 13 ) / x ⁇
  • Upper limit 313 (4.60123 ⁇ 10 15 ) / x
  • FIG. 18 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is in the range G (0.005 or more and 0.02 or less).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.02) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.005) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • FIG. 19 is a diagram showing an example of a preferable range of the bulk donor concentration N Bre when ⁇ 'is the range H (0.01 ⁇ 0.002).
  • the upper limit 311 and lower limit 312 of the donor concentration N Fre (/ cm 3) are the same as those in FIG.
  • the upper limit 313 of the bulk donor concentration N Bre is a value obtained by multiplying the upper limit 311 of the donor concentration N Fre (/ cm 3 ) by the upper limit value (0.01) of ⁇ '.
  • the lower limit 314 of the bulk donor concentration N Bre is a value obtained by multiplying the lower limit 312 of the donor concentration N Fre (/ cm 3 ) by the lower limit value (0.01) of ⁇ '.
  • the upper limit 313 and lower limit 314 of the bulk donor concentration N Bre are as follows.
  • -Lower limit 314 (9.2245 x 10 13 ) / x -Upper limit 313: (9.2245 x 10 14 ) / x
  • the upper limit 313 and the lower limit 314 in each range may have a width of ⁇ 20%.
  • the curve of the lower limit 314 may be smaller than the intrinsic carrier concentration.
  • the intrinsic carrier concentration is 1.45 ⁇ 10 10 / cm 3 at room temperature (for example, 300 K). If the value of the curve of the lower limit 314 is smaller than the intrinsic carrier concentration, the lower limit 314 may be replaced with the intrinsic carrier concentration.
  • FIG. 20 is an example of a top view of the semiconductor device 100.
  • the positions where each member is projected onto the upper surface of the semiconductor substrate 10 are shown.
  • FIG. 20 only a part of the members of the semiconductor device 100 is shown, and some members are omitted.
  • the semiconductor device 100 includes the semiconductor substrate 10 described with reference to FIGS. 1 to 19.
  • the semiconductor substrate 10 has an end side 102 when viewed from above. When simply referred to as a top view in the present specification, it means that the semiconductor substrate 10 is viewed from the top surface side.
  • the semiconductor substrate 10 of this example has two sets of end sides 102 facing each other in a top view. In FIG. 20, the X-axis and the Y-axis are parallel to either end 102. The Z-axis is perpendicular to the upper surface of the semiconductor substrate 10.
  • the semiconductor substrate 10 is provided with an active portion 160.
  • the active portion 160 is a region in which 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 emitter electrode is provided above the active portion 160, but is omitted in FIG. 20.
  • the active unit 160 is provided with at least one of a transistor unit 70 including a transistor element such as an IGBT and a diode unit 80 including a diode element such as a freewheeling diode (FWD).
  • a transistor unit 70 including a transistor element such as an IGBT and a diode unit 80 including a diode element such as a freewheeling diode (FWD).
  • the transistor portion 70 and the diode portion 80 are alternately arranged along a predetermined arrangement direction (X-axis direction in this example) on the upper surface of the semiconductor substrate 10.
  • the active portion 160 may be provided with only one of the transistor portion 70 and the diode portion 80.
  • the symbol “I” is attached to the region where the transistor portion 70 is arranged, and the symbol “F” is attached to the region where the diode portion 80 is arranged.
  • the direction perpendicular to the arrangement direction in the top view may be referred to as a stretching direction (Y-axis direction in FIG. 20).
  • the transistor portion 70 and the diode portion 80 may each have a longitudinal length in the stretching 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 stretching direction of the transistor portion 70 and the diode portion 80 may be the same as the longitudinal direction of each trench portion described later.
  • the diode portion 80 has an N + type cathode region in a region in contact with the lower surface of the semiconductor substrate 10.
  • the region provided with the cathode region is referred to as a diode portion 80. That is, the diode portion 80 is a region that overlaps with the cathode region in the top view.
  • a P + type collector region may be provided on the lower surface of the semiconductor substrate 10 in a region other than the cathode region.
  • the diode portion 80 may also include an extension region 81 in which the diode portion 80 is extended in the Y-axis direction to the gate wiring described later.
  • a collector area is provided on the lower surface of the extension area 81.
  • the transistor portion 70 has a P + type collector region in a region in contact with the lower surface of the semiconductor substrate 10. Further, in the transistor portion 70, a gate structure having an N-type emitter region, a P-type base region, a gate conductive portion and a gate insulating film is periodically arranged on the upper surface side of the semiconductor substrate 10.
  • 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 have pads such as an anode pad, a cathode pad, and a current detection pad.
  • Each pad is arranged in the vicinity of the end side 102.
  • the vicinity of the end side 102 refers to a region between the end side 102 and the emitter electrode in top view.
  • each pad may be connected to an external circuit via wiring such as a wire.
  • 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 FIG. 20, the gate wiring is hatched with diagonal lines.
  • the gate wiring of this example has an outer peripheral gate wiring 130 and an active side gate wiring 129.
  • the outer peripheral gate wiring 130 is arranged between the active portion 160 and the end side 102 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 the top view may be the active portion 160.
  • the outer peripheral gate wiring 130 is connected to the gate pad 164.
  • the outer peripheral gate wiring 130 is arranged above the semiconductor substrate 10.
  • the outer peripheral gate wiring 130 may be a metal wiring containing aluminum or the like.
  • the active side gate wiring 129 is provided in the active portion 160. By providing the active side gate wiring 129 in the active portion 160, it is possible to reduce the variation in the wiring length from the gate pad 164 in each region of the semiconductor substrate 10.
  • the active side gate wiring 129 is connected to the gate trench portion of the active portion 160.
  • the active side gate wiring 129 is arranged above the semiconductor substrate 10.
  • the active side gate wiring 129 may be wiring formed of a semiconductor such as polysilicon doped with impurities.
  • the active side gate wiring 129 may be connected to the outer peripheral gate wiring 130.
  • the active side gate wiring 129 of this example is provided so as to extend in the X-axis direction from one outer peripheral gate wiring 130 to the other outer peripheral gate wiring 130 at substantially the center in the Y-axis direction so as to cross the active portion 160. There is.
  • the transistor portion 70 and the diode portion 80 may be alternately arranged in the X-axis direction in each divided region.
  • the semiconductor device 100 includes a temperature sense unit (not shown) which is a PN junction diode made of polysilicon or the like, and a current detection unit (not shown) which simulates the operation of a transistor unit provided in the active unit 160. May be good.
  • a temperature sense unit (not shown) which is a PN junction diode made of polysilicon or the like
  • a current detection unit (not shown) which simulates the operation of a transistor unit provided in the active unit 160. May be good.
  • the semiconductor device 100 of this example includes an edge termination structure portion 90 between the active portion 160 and the end side 102.
  • the edge termination structure 90 of this example is arranged between the outer peripheral gate wiring 130 and the end side 102.
  • the edge termination structure 90 relaxes the electric field concentration on the upper surface side of the semiconductor substrate 10.
  • the edge termination structure 90 has a plurality of guard rings 92.
  • the guard ring 92 is a P-shaped region in contact with the upper surface of the semiconductor substrate 10.
  • the guard ring 92 may surround the active portion 160 in top view.
  • the plurality of guard rings 92 are arranged at predetermined intervals between the outer peripheral gate wiring 130 and the end side 102.
  • the guard ring 92 arranged on the outside may surround the guard ring 92 arranged on the inside.
  • the outside refers to the side close to the end side 102, and the inside refers to the side close to the outer peripheral gate wiring 130.
  • the edge termination structure 90 may further include at least one of a field plate and a resurf provided in an annular shape surrounding the active portion 160.
  • FIG. 21 is an enlarged view of region A in FIG. 20.
  • the region A is a region including the transistor portion 70, the diode portion 80, and the active side gate wiring 129.
  • 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 examples of trench portions, respectively.
  • the semiconductor device 100 of this example includes an emitter electrode 52 and an active side gate wiring 129 provided above the upper surface of the semiconductor substrate 10.
  • the emitter electrode 52 and the active side gate wiring 129 are provided separately from each other.
  • An interlayer insulating film is provided between the emitter electrode 52 and the active side gate wiring 129 and the upper surface of the semiconductor substrate 10, but this is omitted in FIG.
  • a contact hole 54 is provided so as to penetrate the interlayer insulating film.
  • each contact hole 54 is hatched with diagonal lines.
  • 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 passes through the contact hole 54 and comes into contact with the emitter region 12, the contact region 15, and the base region 14 on the upper surface of the semiconductor substrate 10. Further, the emitter electrode 52 is connected to the dummy conductive portion in the dummy trench portion 30 through a contact hole provided in the interlayer insulating film.
  • the emitter electrode 52 may be connected to the dummy conductive portion of the dummy trench portion 30 at the tip of the dummy trench portion 30 in the Y-axis direction.
  • the active side gate wiring 129 is connected to the gate trench portion 40 through a contact hole provided in the interlayer insulating film.
  • the active side gate wiring 129 may be connected to the gate conductive portion of the gate trench portion 40 at the tip portion 41 of the gate trench portion 40 in the Y-axis direction.
  • the active side gate wiring 129 is not connected to the dummy conductive portion in the dummy trench portion 30.
  • the emitter electrode 52 is made of a material containing metal. In FIG. 21, the range in which the emitter electrode 52 is provided is shown. For example, at least a part of the emitter electrode 52 is formed of an aluminum or aluminum-silicon alloy, for example, a metal alloy such as AlSi or AlSiCu.
  • the emitter electrode 52 may have a barrier metal formed of titanium, a titanium compound, or the like in the lower layer of the region formed of aluminum or the like. Further, the contact hole may have a plug formed by embedding tungsten or the like so as to be in contact with the barrier metal and aluminum or the like.
  • the well region 11 is provided so as to overlap the active side gate wiring 129.
  • the well region 11 is extended to a predetermined width so as not to overlap with the active side gate wiring 129.
  • the well region 11 of this example is provided away from the end of the contact hole 54 in the Y-axis direction on the active side gate wiring 129 side.
  • the well region 11 is a second conductive type region having a higher doping concentration than the base region 14.
  • the base region 14 of this example is P-type, and the well region 11 is P + type.
  • Each of the transistor portion 70 and the diode portion 80 has a plurality of trench portions arranged in the arrangement direction.
  • the transistor portion 70 of this example one or more gate trench portions 40 and one or more dummy trench portions 30 are alternately provided along the arrangement direction.
  • the diode portion 80 of this example is provided with a plurality of dummy trench portions 30 along the arrangement direction.
  • the diode portion 80 of this example is not provided with the gate trench portion 40.
  • the gate trench portion 40 of this example connects two straight portions 39 (portions that are linear along the stretching direction) and two straight portions 39 that extend along the stretching direction perpendicular to the arrangement direction. It may have a tip 41.
  • the stretching direction in FIG. 21 is the Y-axis direction.
  • the tip portion 41 is provided in a curved shape in a top view.
  • the dummy trench portion 30 is provided between the straight portions 39 of the gate trench portion 40.
  • One dummy trench portion 30 may be provided between the straight portions 39, and a plurality of dummy trench portions 30 may be provided.
  • the dummy trench portion 30 may have a linear shape extending in the stretching direction, and may have a straight portion 29 and a tip portion 31 as in the gate trench portion 40.
  • the semiconductor device 100 shown in FIG. 21 includes both a linear dummy trench portion 30 having no tip portion 31 and a dummy trench portion 30 having a tip portion 31.
  • the diffusion depth of the well region 11 may be deeper than the depth of the gate trench portion 40 and the dummy trench portion 30.
  • the ends of the gate trench portion 40 and the dummy trench portion 30 in the Y-axis direction are provided in the well region 11 in the top view. That is, at the end of each trench in the Y-axis direction, the bottom of each trench in the depth direction is covered with the well region 11. Thereby, the electric field concentration at the bottom of each trench can be relaxed.
  • a mesa part is provided between each trench part in the arrangement direction.
  • the mesa portion refers to a region sandwiched between trench portions inside the semiconductor substrate 10.
  • the upper end of the mesa portion is the upper surface of the semiconductor substrate 10.
  • the depth position of the lower end of the mesa portion is the same as the depth position of the lower end of the trench portion.
  • the mesa portion of this example is provided on the upper surface of the semiconductor substrate 10 by extending in the stretching direction (Y-axis direction) along the trench.
  • the transistor portion 70 is provided with a mesa portion 60
  • the diode portion 80 is provided with a mesa portion 61.
  • a mesa portion when simply referred to as a mesa portion in the present specification, it refers to each of the mesa portion 60 and the mesa portion 61.
  • a base region 14 is provided in each mesa section. Of the base region 14 exposed on the upper surface of the semiconductor substrate 10 in the mesa portion, the region closest to the active side gate wiring 129 is referred to as the base region 14-e. In FIG. 21, the base region 14-e arranged at one end in the extending direction of each mesa portion is shown, but the base region 14-e is also arranged at the other end of each mesa portion. Has been done.
  • Each mesa portion may be provided with at least one of a first conductive type emitter region 12 and a second conductive type contact region 15 in a region sandwiched between base regions 14-e in a top view.
  • the emitter region 12 of this example is N + type
  • the contact region 15 is P + type.
  • the emitter region 12 and the contact region 15 may be provided between the base region 14 and the upper surface of the semiconductor substrate 10 in the depth direction.
  • the mesa portion 60 of the transistor portion 70 has an emitter region 12 exposed on the upper surface of the semiconductor substrate 10.
  • the emitter region 12 is provided in contact with the gate trench portion 40.
  • the mesa portion 60 in contact with the gate trench portion 40 may be provided with an exposed contact region 15 on the upper surface of the semiconductor substrate 10.
  • Each of the contact region 15 and the emitter region 12 in the mesa portion 60 is provided from one trench portion in the X-axis direction to the other trench portion.
  • the contact region 15 and the emitter region 12 of the mesa portion 60 are alternately arranged along the extending direction (Y-axis direction) of the trench portion.
  • the contact region 15 and the emitter region 12 of the mesa portion 60 may be provided in a stripe shape along the extending direction (Y-axis direction) of the trench portion.
  • an emitter region 12 is provided in a region in contact with the trench portion, and a contact region 15 is provided in a region sandwiched between the emitter regions 12.
  • the emitter region 12 is not provided in the mesa portion 61 of the diode portion 80.
  • a base region 14 and a contact region 15 may be provided on the upper surface of the mesa portion 61.
  • a contact region 15 may be provided in contact with the respective base regions 14-e in the region sandwiched between the base regions 14-e on the upper surface of the mesa portion 61.
  • a base region 14 may be provided in a region sandwiched between the contact regions 15 on the upper surface of the mesa portion 61.
  • the base region 14 may be arranged over the entire region sandwiched between the contact regions 15.
  • a contact hole 54 is provided above each mesa portion.
  • the contact hole 54 is arranged in a region sandwiched between the base regions 14-e.
  • the contact hole 54 of this example is provided above each region of the contact region 15, the base region 14, and the emitter region 12.
  • the contact hole 54 is not provided in the region corresponding to the base region 14-e and the well region 11.
  • the contact hole 54 may be arranged at the center of the mesa portion 60 in the arrangement direction (X-axis direction).
  • an N + type cathode region 82 is provided in a region adjacent to the lower surface of the semiconductor substrate 10.
  • a P + type collector region 22 may be provided on the lower surface of the semiconductor substrate 10 in a region where the cathode region 82 is not provided.
  • the boundary between the cathode region 82 and the collector region 22 is shown by a dotted line.
  • the cathode region 82 is arranged away from the well region 11 in the Y-axis direction.
  • the pressure resistance can be improved by securing the distance between the P-shaped region (well region 11) formed to a deep position and having a relatively high doping concentration and the cathode region 82.
  • the end of the cathode region 82 of this example in the Y-axis direction is located farther from the well region 11 than the end of the contact hole 54 in the Y-axis direction.
  • the end of the cathode region 82 in the Y-axis direction may be located between the well region 11 and the contact hole 54.
  • FIG. 22A is a diagram showing an example of a bb cross section in FIG. 21.
  • the bb cross section is an XZ plane passing through the emitter region 12 and the cathode region 82.
  • the semiconductor device 100 of this example has a semiconductor substrate 10, an interlayer insulating film 38, an emitter electrode 52, and a collector electrode 24 in the cross section.
  • the interlayer insulating film 38 is provided on the upper surface of the semiconductor substrate 10.
  • the interlayer insulating film 38 is a film containing at least one layer of an insulating film such as silicate glass to which impurities such as boron and phosphorus are added, a thermal oxide film, and other insulating films.
  • the interlayer insulating film 38 is provided with the contact hole 54 described in FIG. 21.
  • 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 made of a metal material such as aluminum.
  • the direction (Z-axis direction) connecting the emitter electrode 52 and the collector electrode 24 is referred to as a depth direction.
  • the semiconductor substrate 10 has an N-type drift region 19.
  • the drift region 19 of this example is an N-shaped region from the lower end of the storage region 16 to the upper end of the buffer region 20.
  • the drift region 19 of this example has the high concentration region 150 described in FIGS. 1 to 19. In FIG. 22A, the high concentration region 150 is hatched with diagonal lines.
  • the high concentration region 150 may be provided in the transistor section 70, may be provided in the diode section 80, or may be provided in both the transistor section 70 and the diode section 80.
  • the high concentration region 150 is a region provided from the upper end of the buffer region 20 toward the upper surface 21.
  • An impurity chemical concentration peak 141 (see FIG. 1 and the like) is arranged at the upper end portion of the high concentration region 150.
  • the drift region 19 may have an N-type bulk donor region 18.
  • the bulk donor region 18 is a region where the doping concentration matches the donor concentration of the bulk donor.
  • the bulk donor region 18 is a region located above the high concentration region 150. In this example, the bulk donor region 18 is provided in each of the transistor portion 70 and the diode portion 80.
  • the mesa portion 60 of the transistor portion 70 is provided with an N + type emitter region 12 and a P-type base region 14 in order from the upper surface 21 side of the semiconductor substrate 10.
  • a bulk donor region 18 is provided below the base region 14.
  • the mesa portion 60 may be provided with an N + type storage region 16.
  • the storage region 16 is located between the base region 14 and the bulk donor region 18.
  • the emitter region 12 is exposed on the upper surface 21 of the semiconductor substrate 10 and is provided in contact with the gate trench portion 40.
  • the emitter region 12 may be in contact with the trench portions on both sides of the mesa portion 60.
  • the emitter region 12 has a higher doping concentration than the bulk donor region 18.
  • the base region 14 is provided below the emitter region 12.
  • the base region 14 of this example 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.
  • the storage area 16 is provided below the base area 14.
  • the accumulation region 16 is an N + type region having a higher doping concentration than the drift region 19.
  • the accumulation region 16 may have a higher doping concentration than the high concentration region 150.
  • IE effect carrier injection promoting effect
  • the storage region 16 may be provided so as to cover the entire lower surface of the base region 14 in each mesa portion 60.
  • the mesa portion 61 of the diode portion 80 is provided with a P-type base region 14 in contact with the upper surface 21 of the semiconductor substrate 10. Below the base region 14, a bulk donor region 18 is provided. In the mesa portion 61, the accumulation region 16 may be provided below the base region 14.
  • an N + type buffer region 20 is provided on the lower surface 23 side of the high concentration region 150.
  • the structure of the buffer area 20 is the same as that of the buffer area 20 described with reference to FIGS. 1 to 19.
  • the buffer region 20 may function as a field stop layer that prevents the depletion layer extending from the lower end of the base region 14 from reaching the P + type collector region 22 and the N + type cathode region 82.
  • a P + type collector region 22 is provided below the buffer region 20.
  • the collector region 22 is an example of the lower surface region 201 described in FIGS. 1 to 19.
  • the acceptor concentration in the collector region 22 is higher than the acceptor concentration in the base region 14.
  • the collector region 22 may include the same acceptors as the base region 14, or may include different acceptors.
  • the acceptor of the collector region 22 is, for example, boron.
  • an N + type cathode region 82 is provided below the buffer region 20.
  • the cathode region 82 is an example of the lower surface region 201 described in FIGS. 1 to 19.
  • the donor concentration in the cathode region 82 is higher than the donor concentration in the high concentration region 150.
  • the donor of the cathode region 82 is, for example, hydrogen or phosphorus.
  • the elements that serve as donors and acceptors in each region are not limited to the above-mentioned examples.
  • the collector region 22 and the cathode region 82 are exposed on the lower surface 23 of the semiconductor substrate 10 and are connected to the collector electrode 24.
  • the collector electrode 24 may come into contact with the entire lower surface 23 of the semiconductor substrate 10.
  • the emitter electrode 52 and the collector electrode 24 are made of a metal material such as aluminum.
  • One or more gate trench portions 40 and one or more dummy trench portions 30 are provided on the upper surface 21 side of the semiconductor substrate 10. Each trench portion penetrates the base region 14 from the upper surface 21 of the semiconductor substrate 10 and reaches the drift region 19. In the 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 doping regions and reaches the bulk donor region 18. The penetration of the trench portion through the doping region is not limited to those manufactured in the order of forming the doping region and then forming the trench portion. Those in which a doping region is formed between the trench portions after the trench portion is formed are also included in those in which the trench portion penetrates the doping region.
  • the transistor portion 70 is provided with a gate trench portion 40 and a dummy trench portion 30.
  • the diode portion 80 is provided with a dummy trench portion 30 and is not provided with a gate trench portion 40.
  • the boundary between the diode portion 80 and the transistor portion 70 in the X-axis direction is the boundary between the cathode region 82 and the collector region 22.
  • the gate trench portion 40 has a gate trench, a gate insulating film 42, and a gate conductive portion 44 provided on the upper surface 21 of the semiconductor substrate 10.
  • the gate insulating film 42 is provided so as to cover the inner wall of the gate trench.
  • the gate insulating film 42 may be formed by oxidizing or nitriding the semiconductor on the inner wall of the gate trench.
  • the gate conductive portion 44 is provided inside the gate trench and inside the gate insulating film 42. That is, the gate insulating film 42 insulates the gate conductive portion 44 and the semiconductor substrate 10.
  • the gate conductive portion 44 is formed of a conductive material such as polysilicon.
  • the gate conductive portion 44 may be provided longer than the base region 14 in the depth direction.
  • the gate trench portion 40 in the cross section is covered with an interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10.
  • the gate conductive portion 44 is electrically connected to the gate wiring. When a predetermined gate voltage is applied to the gate conductive portion 44, a channel due to an electron inversion layer is formed on the surface layer of the interface in the base region 14 in contact with the gate trench portion 40.
  • the dummy trench portion 30 may have the same structure as the gate trench portion 40 in the cross section.
  • the dummy trench portion 30 has a dummy trench, a dummy insulating film 32, and a dummy conductive portion 34 provided on the upper surface 21 of the semiconductor substrate 10.
  • the dummy conductive portion 34 may be connected to an electrode different from the gate pad.
  • the dummy conductive portion 34 may be connected to a dummy pad (not shown) connected to an external circuit different from the gate pad, and control different from that of the gate conductive portion 44 may be performed.
  • the dummy conductive portion 34 may be electrically connected to the emitter electrode 52.
  • the dummy insulating film 32 is provided so as to cover the inner wall of the dummy trench.
  • the dummy conductive portion 34 is provided inside the dummy trench and inside the dummy insulating film 32.
  • the dummy insulating film 32 insulates the dummy conductive portion 34 and the semiconductor substrate 10.
  • the dummy conductive portion 34 may be formed of the same material as the gate conductive portion 44.
  • 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.
  • the gate trench portion 40 and the dummy trench portion 30 of this example are covered with an interlayer insulating film 38 on the upper surface 21 of the semiconductor substrate 10.
  • the bottom of the dummy trench portion 30 and the gate trench portion 40 may be curved downward (curved in cross section).
  • the semiconductor substrate 10 has, similar to any of the examples described in FIGS. 19 from FIG. 1, the impurity chemical concentration C I, hydrogen chemical concentration C H, and the distribution of the doping density D d. According to the semiconductor device 100 of this example, by providing the high concentration region 150, it is possible to suppress the variation in the doping concentration in the drift region 19.
  • FIG. 22B is a diagram showing a distribution example of the doping concentration D d on the dd line of FIG. 22A.
  • the dd line is a line parallel to the Z axis passing through the collector region 22 and the mesa portion 60.
  • the distribution of the doping concentration D d in this example is the same as the distribution of the doping concentration D d shown in FIG. 2 from the collector region 22 to the doping concentration peak 121.
  • the doping concentration D d of this example has a concentration peak in each of the accumulation region 16, the base region 14, and the emitter region 12.
  • the semiconductor substrate 10 of this example has a bulk donor region 18 between the storage region 16 and the doping concentration peak 121.
  • the bulk donor region 18 may be in contact with the storage region 16. That is, at the boundary between the bulk donor region 18 and the accumulation region 16 , the doping concentration D d may be continuously increased from the bulk donor concentration D b to the apex of the concentration peak of the accumulation region 16.
  • FIG. 23 is a diagram showing another example of the bb cross section in FIG. 21.
  • the semiconductor device 100 of this example differs from the example of FIG. 22A in that the high concentration region 150 is provided over the entire drift region 19.
  • Other structures may be the same as in the example of FIG. 22A.
  • the high concentration region 150 of this example may be provided from the upper end of the buffer region 20 to a position in contact with the storage region 16.
  • the high concentration region 150 may be formed up to the inside of the accumulation region 16.
  • the second doping concentration peak 121 may be located in the accumulation region 16.
  • the high concentration region 150 may be provided up to a position in contact with the base region 14. According to this example, the variation in the doping concentration can be suppressed over the entire drift region 19.

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  • Thin Film Transistor (AREA)
  • Recrystallisation Techniques (AREA)
  • Metal-Oxide And Bipolar Metal-Oxide Semiconductor Integrated Circuits (AREA)
PCT/JP2021/014179 2020-04-01 2021-04-01 半導体装置および半導体装置の製造方法 Ceased WO2021201235A1 (ja)

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JP2022511136A JP7452632B2 (ja) 2020-04-01 2021-04-01 半導体装置および半導体装置の製造方法
US17/703,928 US20220216055A1 (en) 2020-04-01 2022-03-24 Semiconductor device and manufacturing method of semiconductor device

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JP2013138172A (ja) * 2011-11-30 2013-07-11 Denso Corp 半導体装置
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JP6733739B2 (ja) * 2016-10-17 2020-08-05 富士電機株式会社 半導体装置
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JP2013138172A (ja) * 2011-11-30 2013-07-11 Denso Corp 半導体装置
WO2017047285A1 (ja) * 2015-09-16 2017-03-23 富士電機株式会社 半導体装置および半導体装置の製造方法
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