Patent ID: 9520318
Filing Date: 2016-12-13
CPC Classification: H01L

Claim Text:
1. A method for manufacturing a semiconductor device including a cell region and a peripheral region formed outside the cell region, comprising: (a) providing a semiconductor substrate including a first epitaxial layer of a first conductivity type formed over a main surface thereof, (b) doping a lower band gap impurity for making the band gap smaller than the band gap of the first epitaxial layer before doping into the first epitaxial layer in the cell region, and thereby forming a lower band gap region, (c) after the step (b), forming a plurality of first column regions of a second conductivity type which is an opposite conductivity type to the first conductivity type in such a manner as to be separated from one another in the first epitaxial layer extending from the cell region to the peripheral region, (d) after the step (c), forming a second epitaxial layer of the first conductivity type over the first epitaxial layer extending from the cell region to the peripheral region, (e) after the step (d), forming a plurality of second column regions of the second conductivity type to be electrically coupled with the first column regions, respectively, in such a manner as to be separated from one another in the second epitaxial layer, (f) after the step (e), repeatedly carrying out the same step as the step (d), and the same step as the step (e), and thereby forming a third epitaxial layer including a plurality of third column regions formed therein to an Nth epitaxial layer including a plurality of Nth column regions formed therein in lamination over the second epitaxial layer, and (g) after the step (f), forming an element part at the surface of the Nth epitaxial layer.