Patent ID: 9466689
Filing Date: 2016-10-11
CPC Classification: H01L

Claim Text:
1. A method for manufacturing a semiconductor device including a first electrode that is provided on a front surface of a semiconductor substrate of a first conductivity type and a second electrode that is provided on a rear surface of the semiconductor substrate, the method comprising, in the order recited: thinning the semiconductor substrate by grinding or etching to uniformly reduce the thickness thereof; introducing impurities other than protons into the rear surface of the semiconductor substrate; activating the impurities introduced into the rear surface of the semiconductor substrate using a first annealing process to form a first semiconductor layer, which is a contact portion in contact with the second electrode, in a surface layer of the rear surface of the semiconductor substrate; radiating protons to the rear surface of the semiconductor substrate with an acceleration energy having a range Rp that extends only within the semiconductor substrate a plurality of times; and activating the protons radiated to the rear surface of the semiconductor substrate using a second annealing process to form a second semiconductor layer of the first conductivity type, which has a plurality of peak impurity concentrations that correspond to the range Rp and which has higher impurity concentrations than the semiconductor substrate, in a region that is deeper than the first semiconductor layer from the rear surface of the semiconductor substrate, wherein the impurity concentrations of the plurality of peak impurity concentrations are not reduced by the first annealing process.