Patent attributes
A wafer fabrication method includes a first step of forming a plurality of first channel regions in a first region on a surface of a water, a second step of forming a plurality of second channel regions having an impurity concentration different from an impurity concentration of the first channel regions, a third step of forming a plurality of third channel regions in a third region on the surface of the water, and a fourth step of forming a plurality of fourth channel regions having an impurity concentration different from an impurity concentration of the third channel regions in a fourth region, wherein the first region and the second region are divided by a first line segment on the wafer, and the third and fourth regions are divided by a second line segment intersecting with the first line segment on the wafer.