US 11,942,535 B2
Semiconductor device
Yosuke Sakurai, Azumino (JP); and Yuichi Onozawa, Matsumoto (JP)
Assigned to FUJI ELECTRIC CO., LTD., Kanagawa (JP)
Filed by FUJI ELECTRIC CO., LTD., Kanagawa (JP)
Filed on Aug. 24, 2021, as Appl. No. 17/409,819.
Application 17/409,819 is a continuation of application No. PCT/JP2020/032871, filed on Aug. 31, 2020.
Claims priority of application No. 2019-167090 (JP), filed on Sep. 13, 2019.
Prior Publication US 2021/0384332 A1, Dec. 9, 2021
Int. Cl. H01L 29/739 (2006.01); H01L 29/06 (2006.01)
CPC H01L 29/7396 (2013.01) [H01L 29/0607 (2013.01); H01L 29/0696 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A semiconductor device, comprising:
a drift region that is of a first conductivity type and is provided in a semiconductor substrate;
a base region that is of a second conductivity type and is provided above the drift region;
an accumulation region that is of the first conductivity type, is provided between the base region and the drift region, and has a higher doping concentration than the drift region; and
an electric field relaxation region that is provided between the base region and the accumulation region, and has a doping concentration that is lower than a peak of the doping concentration of the accumulation region,
wherein
a boundary between the electric field relaxation region and the accumulation region is a location for a half-value for the peak of the doping concentration of the accumulation region, and
an integrated concentration of the electric field relaxation region is greater than or equal to 5E14 cm−2 and less than or equal to 5E15 cm−2.