Patent ID: 11894426
Assignee: FUJI ELECTRIC CO., LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A semiconductor device comprising:
a semiconductor substrate including a bulk donor; and
a first buffer region of a first conductivity type, the first buffer region being provided on a lower surface side of the semiconductor substrate and having one or more doping concentration peaks and one or more hydrogen concentration peaks in a depth direction of the semiconductor substrate, wherein
a doping concentration at a shallowest concentration peak, out of the doping concentration peaks of the first buffer region, closest to the lower surface of the semiconductor substrate is 50 times as high as a bulk donor concentration of the semiconductor substrate or lower, and
the doping concentration at the shallowest concentration peak is lower than a reference carrier concentration obtained when current that is 1/10 of rated current flows between an upper surface and the lower surface of the semiconductor substrate.