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US-12628584-B2 - Semiconductor device and manufacturing method of semiconductor device

US12628584B2US 12628584 B2US12628584 B2US 12628584B2US-12628584-B2

Abstract

Provided is a semiconductor device including: a semiconductor substrate having an upper surface and a lower surface, and containing a bulk donor; a buffer region of a first conductivity type; a high-concentration region of a first conductivity type; and a lower surface region of a first conductivity type or a second conductivity type, wherein a shallowest doping concentration peak closest to the lower surface of the semiconductor substrate among the doping concentration peaks of the buffer region is a concentration peak of a hydrogen donor having a concentration higher than the other doping concentration peaks, and a ratio A/B of a peak concentration A of the shallowest doping concentration peak and an average peak concentration B of the other doping concentration peaks is 200 or less.

Inventors

  • Misaki Uchida
  • Takashi Yoshimura
  • Hiroshi TAKISHITA
  • Motoyoshi KUBOUCHI
  • Michio Nemoto

Assignees

  • FUJI ELECTRIC CO., LTD.

Dates

Publication Date
20260512
Application Date
20220324
Priority Date
20200401

Claims (14)

  1. 1 . A semiconductor device comprising: a semiconductor substrate having an upper surface and a lower surface, and containing a bulk donor; a buffer region of a first conductivity type which is disposed on the lower surface side of the semiconductor substrate and has two or more doping concentration peaks in a depth direction of the semiconductor substrate; a high-concentration region of a first conductivity type which is disposed between the buffer region and the upper surface of the semiconductor substrate, and has a donor concentration higher than a bulk donor concentration; a lower surface region of a first conductivity type or a second conductivity type which is disposed between the buffer region and the lower surface of the semiconductor substrate and has a doping concentration higher than the high concentration region; and an impurity chemical concentration peak is provided in the upper surface side of the semiconductor substrate of the high-concentration region, wherein a doping concentration at a position of the impurity chemical concentration peak is less than an impurity chemical concentration of the impurity chemical concentration peak, wherein a shallowest doping concentration peak closest to the lower surface of the semiconductor substrate among the doping concentration peaks of the buffer region is a concentration peak of a hydrogen donor having a concentration higher than other doping concentration peaks, the high-concentration region is provided from the shallowest doping concentration peak to the impurity chemical concentration peak, the high-concentration region includes a uniform region in which a doping concentration is substantially uniform, a doping concentration distribution of the uniform region is within a range in which a value of the doping concentration distribution is within ±10% of an average concentration of the doping concentration distribution in a first range in the uniform region, and when a length of the high-concentration region in the depth direction is set to Z L and a center between the shallowest doping concentration peak and the impurity chemical concentration peak in the depth direction is set to Z 12C , the first range is a section with a length of 0.5Z L including the center Z 12C , the length of the first range is set between two points separated by 0.25Z L from the center Z 12C between Z 1 and Z 2 , toward the first depth position Z 1 side and the second depth position Z 2 side, and in the high-concentration region, a hydrogen chemical concentration monotonically decreases from the buffer region beyond the impurity chemical concentration peak toward the upper surface.
  2. 2 . The semiconductor device according to claim 1 , wherein the impurity chemical concentration decreases more steeply in an upper tail, in which an impurity chemical concentration decreases from a local maximum of the impurity chemical concentration peak toward the upper surface side, than in a lower tail in which the impurity chemical concentration decreases from the local maximum of the impurity chemical concentration peak toward the lower surface side.
  3. 3 . The semiconductor device according to claim 1 , wherein the high-concentration region has a length of 50 μm or more in the depth direction.
  4. 4 . The semiconductor device according to claim 1 , wherein a ratio A/B of a peak concentration A of the shallowest doping concentration peak and an average peak concentration B of the other doping concentration peaks is 200 or less.
  5. 5 . The semiconductor device according to claim 1 , wherein the high-concentration region has a length of 80 μm or more from the shallowest doping concentration peak toward the upper surface of the semiconductor substrate.
  6. 6 . The semiconductor device according to claim 1 , wherein the high-concentration region has a length of 40% or more of a thickness of the semiconductor substrate in the depth direction.
  7. 7 . The semiconductor device according to claim 4 , wherein the ratio A/B is 2 or more.
  8. 8 . The semiconductor device according to claim 1 , wherein a ratio C/D of a dose amount C of the shallowest doping concentration peak and a total dose amount D of the other doping concentration peaks is 6 or more and 100 or less.
  9. 9 . The semiconductor device according to claim 1 , further comprising: an accumulation region which is disposed on the upper surface side of the semiconductor substrate, and has a doping concentration higher than the high-concentration region, wherein the high-concentration region is provided up to a position in contact with the accumulation region.
  10. 10 . The semiconductor device according to claim 1 , wherein a minimum value of the doping concentration of the high-concentration region is two times or more of the bulk donor concentration.
  11. 11 . The semiconductor device according to claim 1 , wherein doping distribution increases from the uniform region toward the impurity chemical concentration peak while a hydrogen chemical concentration decreases.
  12. 12 . The semiconductor device according to claim 1 , wherein from a depth position of the impurity chemical concentration peak toward the upper surface side, a portion where the doping concentration coincides with the bulk donor concentration is provided.
  13. 13 . The semiconductor device according to claim 1 , wherein the doping concentration distribution of the uniform region is within a range in which a difference between a maximum value and a minimum value of the doping concentration is within 50% of the maximum value of the doping concentration.
  14. 14 . The semiconductor device according to claim 1 , wherein a drift region of the first conductivity-type is disposed between the buffer region and the upper surface, the drift region contains the high concentration region, in which a doping concentration of the drift region is a same as the bulk donor concentration.

Description

The contents of the following Japanese patent applications are incorporated herein by reference: NO. 2020-066324 filed in JP on Apr. 1, 2020, andPCT/JP2021/014146 filed in WO on Apr. 1, 2021. BACKGROUND 1. Technical Field The present invention relates to a semiconductor device and a manufacturing method of the semiconductor device. 2. Related Art Conventionally, a technique of implanting hydrogen ions into a semiconductor wafer to adjust the doping concentration of the semiconductor wafer has been known (see, for example, Patent Document 1). Patent Document 1: US No. 2015/0050754 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view illustrating an example of the manufacturing method of a semiconductor device 100. FIG. 2 illustrates the distributions of a lattice defect density DV, a hydrogen chemical concentration CH, a doping concentration Dd, and an impurity chemical concentration CI in a depth direction at positions illustrated by line A-A in FIG. 1. FIG. 3 illustrates the distributions of lattice defect density DV, hydrogen chemical concentration CH, doping concentration Dd, and impurity chemical concentration CI according to a comparative example. FIG. 4 is a diagram illustrating the distributions of hydrogen chemical concentration CH and doping concentration Dd in the vicinity of a buffer region 20. FIG. 5A is a flowchart illustrating an example of a manufacturing method of the semiconductor device 100. FIG. 5B is a flowchart illustrating another example of the manufacturing method of the semiconductor device 100. FIG. 6A is a flowchart illustrating another example of the manufacturing method of the semiconductor device 100. FIG. 6B is a flowchart illustrating another example of the manufacturing method of the semiconductor device 100. FIG. 7 is a diagram illustrating an example of the distribution of hydrogen chemical concentration CH in the vicinity of the buffer region 20. FIG. 8 is a diagram illustrating changes in the doping concentration Dd in the vicinity of the buffer region 20 when the dose amount of hydrogen ions with respect to a first depth position Z1 is changed. FIG. 9A is a diagram for explaining the relationship between a hydrogen chemical concentration peak 131-1 and a doping concentration peak 111-1. FIG. 9B is a diagram for explaining the relationship between an impurity chemical concentration peak 141 and a doping concentration peak 121. FIG. 9C is a diagram for explaining the gradient of a lower tail 142. FIG. 10A is a diagram for explaining another definition of normalization of the gradient of the lower tail 112. FIG. 10B is a diagram for explaining another definition of normalization of the gradient of a lower tail 122. FIG. 11 is a graph illustrating the relationship between ε′ and γ indicated by Expression (12) for each β. FIG. 12 is a diagram illustrating an example of a preferred range for a bulk donor concentration NBre. FIG. 13 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range B (0.01 or more, and 0.333 or less). FIG. 14 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range C (0.03 or more, and 0.25 or less). FIG. 15 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range D (0.1 or more, and 0.2 or less). FIG. 16 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range E (0.001 or more, and 0.1 or less). FIG. 17 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range F (0.002 or more, and 0.05 or less). FIG. 18 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range G (0.005 or more, and 0.02 or less). FIG. 19 is a diagram illustrating an example of a preferred range for the bulk donor concentration NBre in a case where ε′ is in Range H (0.01±0.002). FIG. 20 is an example of a top view of the semiconductor device 100. FIG. 21 is an enlarged view of a region A in FIG. 20. FIG. 22A is a diagram illustrating an example of a cross section b-b in FIG. 21. FIG. 22B is a diagram illustrating an example of the distribution of the doping concentration Dd in line d-d of FIG. 22A. FIG. 23 is a diagram illustrating another example of the cross section b-b in FIG. 21. DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Not all combinations of features described in the embodiments are essential to the solution of the invention. As used herein, one side in a direction parallel to a depth direction of a semiconductor substrate is referred to as “upper” and the other side is referred to as “lower”. On