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DE-112018007102-B4 - SEMICONDUCTOR DEVICE

DE112018007102B4DE 112018007102 B4DE112018007102 B4DE 112018007102B4DE-112018007102-B4

Abstract

Semiconductor device (200) comprising a semiconductor substrate (10) in which a drift region (18) having a first conductivity type is arranged, wherein the semiconductor device (200) comprises: comprising an anode region (16) and a second conductivity type which is arranged between an upper surface (11) of the semiconductor substrate and the drift region (18); having a cathode region (24) of the first conductivity type, which is located between a lower surface (13) of the semiconductor substrate and the drift region (18) and has a higher doping concentration than the drift region (18); having a buried area (22) of the second conductivity type, which is arranged above the cathode area (24); a dielectric interlayer film (26) which is arranged over the upper surface (11) of the semiconductor substrate, and in which a contact opening (56) is arranged for exposing part of the anode region; and an electrode (12) on the side of the upper surface (11) in contact with the anode area (16) in the contact opening (56), wherein the buried area (22) has a buried end section area (22-e) which is arranged continuously from an area below the contact opening (56) to an area below the dielectric interlayer film (26), while in a cross-section perpendicular to the upper surface (11) of the semiconductor substrate below an end section of the contact opening (56), and wherein the buried end section (22-e), which is arranged under the dielectric interlayer film (26), is shorter than the buried End section area (22-e), which is arranged in a first direction parallel to the upper surface (11) of the semiconductor substrate under the contact opening (56).

Inventors

  • Takahiro Tamura
  • Yuichi Onozawa

Assignees

  • FUJI ELECTRIC CO., LTD.

Dates

Publication Date
20260513
Application Date
20181121
Priority Date
20180216

Claims (12)

  1. Semiconductor device (200) comprising a semiconductor substrate (10) in which a drift region (18) is arranged, the semiconductor device (200) comprising: an anode region (16) comprising a second conductivity type, which is arranged between an upper surface (11) of the semiconductor substrate and the drift region (18); a cathode region (24) comprising the first conductivity type, which is arranged between a lower surface (13) of the semiconductor substrate and the drift region (18) and has a higher doping concentration than the drift region (18); a buried region (22) comprising the second conductivity type, which is arranged above the cathode region (24); a dielectric intermediate layer film (26) which is arranged over the upper surface (11) of the semiconductor substrate, and in which a contact opening (56) is arranged for exposing part of the anode area; and an electrode (12) on the side of the upper surface (11) in contact with the anode region (16) in the contact opening (56), wherein the buried region (22) has a buried end section region (22-e) which is arranged continuously from a region below the contact opening (56) to a region below the dielectric interlayer film (26), while in a cross-section perpendicular to the upper surface (11) of the semiconductor substrate below an end section of the contact opening (56), and wherein the buried end section region (22-e) which is arranged below the dielectric interlayer film (26) is shorter than the buried end section region (22-e) which is arranged in a first direction parallel to the upper surface (11) of the semiconductor substrate below the contact opening (56).
  2. Semiconductor device (200) according to Claim 1 , wherein the length of the buried end section area located below the dielectric interlayer film (26) is 20 µm or more in the first direction.
  3. Semiconductor device (200) according to Claim 1 or 2 , wherein: the buried area (22) is separated in the first direction and arranged at a distance of a predetermined slot width; and a length of the buried end section area, which is arranged under the dielectric interlayer film (26), is greater in the first direction than the slot width.
  4. Semiconductor device (200) according to any of the Claims 1 until 3 , wherein: the anode region (16) is arranged from the region under the contact opening (56) to the region under the dielectric interlayer film (26), while in cross-section it runs perpendicular to the upper surface (11) of the semiconductor substrate under the end section of the contact opening (56); and the buried end section region (22-e) which is arranged under the dielectric interlayer film (26) is shorter than the anode region (16) which is arranged in the first direction under the dielectric interlayer film (26).
  5. Semiconductor device (200) according to any of the Claims 1 until 4 , wherein: the cathode region (24) is arranged from the region under the contact opening (56) to the region under the dielectric interlayer film (26), while in cross-section it runs perpendicular to the upper surface (11) of the semiconductor substrate under the end section of the contact opening (56); and the buried end section region (22-e) which is arranged under the dielectric interlayer film (26) is shorter than the cathode region (24) which is arranged in the first direction under the dielectric interlayer film (26).
  6. Semiconductor device (200) according to Claim 5 , wherein the buried end section region (22-e) which is arranged under the dielectric interlayer film (26) is shorter in the first direction by 10 µm or more than the cathode region (24) which is arranged under the dielectric interlayer film (26).
  7. Semiconductor device (200) according to any of the Claims 1 until 6 , wherein: the anode region (16) and the cathode region (24) are arranged from the region below the contact opening (56) to the region below the dielectric interlayer film (26), while in cross-section they extend perpendicular to the upper surface (11) of the semiconductor substrate below the end section of the contact opening (56); and the cathode region (24) which is arranged below the dielectric interlayer film (26) is shorter in the first direction than the anode region (16) which is arranged below the dielectric interlayer film (26).
  8. Semiconductor device (200) according to Claim 7 , wherein a length in the cathode region (24) which is arranged under the dielectric interlayer film (26) is in the first direction half or more of a length in the anode region (16) which is arranged under the dielectric interlayer film (26).
  9. Semiconductor device (200) according to Claim 7 or 8 , wherein a distance in the first direction between an end section of the cathode region and an end section of the anode region is greater than a thickness of the anode region in a second direction perpendicular to the upper surface (11) of the semiconductor substrate.
  10. Semiconductor device (200) according to any of the Claims 7 until 9 , wherein a distance in the first direction between the end section of the cathode region and the end section of the anode region is greater than a thickness of the dielectric interlayer film in a second direction perpendicular to the upper surface (11) of the semiconductor substrate.
  11. Semiconductor device (200) according to Claim 7 or 8 , wherein: the anode region (16) has a curved section (17) in the end region perpendicular to the upper surface (11) of the semiconductor substrate in cross-section; and the cathode region (24) is not arranged below the curved section (17).
  12. Semiconductor device (200) according to any of the Claims 1 until 11 , wherein a length of the buried end section area which is arranged below the contact opening (56) is equal to or greater than a thickness of the semiconductor substrate in the first direction.

Description

1. TECHNICAL AREA The present invention relates to a semiconductor device. 2. STATE OF THE ART So far, a semiconductor device has been proposed in which an opening for contact is arranged in an insulating film on a semiconductor substrate and the semiconductor substrate and an anode electrode are connected to each other (see for example PTL 1). PTL 1: International Publication No. WO 2014 / 156 849 A1 with corresponding US family member no. US 2015 / 0 364 613 A1 Since a current tends to concentrate in the end section of a contact opening, the current density is preferably reduced. (Article 1) To solve the problem described above, according to one aspect of the present invention, a semiconductor device is provided which has a semiconductor substrate in which a first conductivity type is arranged in a drift region. The semiconductor device can have a second conductivity type arranged between an upper surface of the semiconductor substrate and the drift region, and in which a cathode region has a higher doping concentration than the drift region. The semiconductor device can have a buried region of the second conductivity type arranged above the cathode region. The semiconductor device can have a dielectric interlayer film arranged above the upper surface of the semiconductor substrate, in which a contact opening is arranged for exposing a portion of the anode region. The semiconductor device can have an electrode on the side of the upper surface which is in contact with the anode region in the contact opening. The buried region can include a buried end section that extends continuously from a region below the contact opening to a region below the dielectric interlayer film, while running in cross-section perpendicular to the upper surface of the semiconductor substrate below an end section of the contact opening. The buried end section located below the dielectric interlayer film can be shorter than the buried end section located below the contact opening in a first direction parallel to the upper surface of the semiconductor substrate. (Article 2) The length of the buried end section area, which is located under the dielectric interlayer film, can be 20 µm or more in the first direction. (Article 3) The buried area can be divided in the first direction and arranged at a distance of a predetermined slot width. The length of the buried end section, which is located beneath the dielectric interlayer film, can be greater than the slot width in the first direction. (Article 4) The anode region can extend from the area below the contact opening to the area below the dielectric interlayer film, while in cross-section it runs perpendicular to the upper surface of the semiconductor substrate below the end section of the contact opening. The buried end section, which is located below the dielectric interlayer film, can be shorter in the first direction than the anode region located below the dielectric interlayer film. (Article 5) The cathode region can extend from the area below the contact opening to the area below the dielectric interlayer film, while in cross-section it runs perpendicular to the upper surface of the semiconductor substrate below the end section of the contact opening. The buried end section, which is located below the dielectric interlayer film, can be shorter in the first direction than the cathode region located below the dielectric interlayer film. (Article 6) The buried end section region, which is located below the dielectric interlayer film, can be 10 µm or more shorter in the first direction than the cathode region. which is located beneath the dielectric interlayer film. (Article 7) The anode and cathode regions can extend from the area below the contact opening to the area below the dielectric interlayer film, while in cross-section they run perpendicular to the upper surface of the semiconductor substrate below the end portion of the contact opening. The cathode region located below the dielectric interlayer film can be shorter in the first direction than the anode region located below the dielectric interlayer film. (Article 8) A length in the cathode region, which is arranged under the dielectric interlayer film, can be half or more of a length in the anode region, which is arranged under the dielectric interlayer film, in the first direction. (Article 9) A distance in the first direction between an end section of the cathode region and an end section of the anode region can be greater than a thickness of the anode region in a second direction perpendicular to the upper surface of the semiconductor substrate. (Article 10) The distance in the first direction between the end section of the cathode region and the end section of the anode region can be greater than the thickness of the dielectric interlayer film in the second direction perpendicular to the upper surface of the semiconductor substrate. (Article 11) The anode region can have a curved section at its end, perpendicular to the