US 12,266,719 B2
Semiconductor device, manufacturing method of semiconductor device, and power conversion device comprising semiconductor device
Yoshiharu Kato, Matsumoto (JP); Yosuke Sakurai, Azumino (JP); Seiji Noguchi, Matsumoto (JP); and Takashi Yoshimura, Matsumoto (JP)
Assigned to FUJI ELECTRIC CO., LTD., Kanagawa (JP)
Filed by FUJI ELECTRIC CO., LTD., Kanagawa (JP)
Filed on Feb. 23, 2022, as Appl. No. 17/679,039.
Application 17/679,039 is a continuation of application No. PCT/JP2021/008535, filed on Mar. 4, 2021.
Claims priority of application No. 2020-037266 (JP), filed on Mar. 4, 2020; and application No. 2020-189021 (JP), filed on Nov. 12, 2020.
Prior Publication US 2022/0181472 A1, Jun. 9, 2022
Int. Cl. H01L 29/739 (2006.01); H01L 29/10 (2006.01); H01L 29/36 (2006.01)
CPC H01L 29/7397 (2013.01) [H01L 29/1095 (2013.01); H01L 29/36 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A semiconductor device comprising:
a semiconductor substrate having an upper surface and a lower surface and provided with a drift region of a first conductivity type;
a buffer region of the first conductivity type arranged between the drift region and the lower surface, wherein a doping concentration distribution in a depth direction of the semiconductor substrate has three or more concentration peaks; and
a collector region of a second conductivity type arranged between the buffer region and the lower surface,
wherein the three or more concentration peaks in the buffer region include:
a first concentration peak closest to the lower surface;
a second concentration peak closest, next to the first concentration peak, to the lower surface, arranged 5 μm or more distant from the lower surface in the depth direction, and having a doping concentration lower than the first concentration peak, the doping concentration being less than 1.0×1015/cm3; and
a high concentration peak arranged farther from the lower surface than the second concentration peak, and having a higher doping concentration than the second concentration peak,
wherein the doping concentration has a minimum value between each adjacent pair of the three or more concentration peaks, and
wherein the minimum value of the doping concentration between each adjacent pair of the three or more concentration peaks is 2.0×1014/cm3 or more and 5.0×1014/cm3 or less.