Patent ID: 9722016
Date: 2017-08-01
CPC Classifications: H01L

Claim:
1. A method for producing a semiconductor device including a breakdown voltage holding pn junction that is provided in one main surface of an n-type semiconductor substrate and an n-type field stop layer that is provided in the other main surface of the n-type semiconductor substrate, has a lower resistance than the n-type semiconductor substrate, and suppresses the spreading of a depletion layer from the breakdown voltage holding pn junction, comprising: a proton irradiation step of repeatedly performing proton irradiation a plurality of times from the other main surface of the n-type semiconductor substrate to form the n-type field stop layer in the other main surface of the n-type semiconductor substrate, wherein, in the proton irradiation step, whenever the proton irradiation is repeated, the next proton irradiation is performed so as to compensate for a reduction in mobility due to a disorder which remains after the previous proton irradiation.