A semiconductor wafer includes first and second main surfaces opposite to each other along a vertical direction, and a side surface encircling the semiconductor wafer. A lateral distance perpendicular to the vertical direction between the side surface and a center of the semiconductor wafer includes first and second parts. The first part extends from the side surface to the second part and the second part extends from the first part to the center. An average concentration of at least one of nitrogen and oxygen in the first part is greater than 5×1014 cm−3 and exceeds an average concentration of the at least one of nitrogen and oxygen in the second part by more than 20% of the average concentration of the at least one of nitrogen and oxygen in the second part.