Abstract: Provided is a semiconductor device in which a doping concentration peak of a buffer region has a local maximum at which a doping concentration shows a local maximum value, a lower tail in which the doping concentration monotonously decreases from the local maximum toward a lower surface, and an upper tail in which the doping concentration monotonously decreases from the local maximum toward an upper surface, and at least one of the doping concentration peaks of the buffer region is a gradual concentration peak in which a slope ratio obtained by dividing an absolute value of a slope of the upper tail by an absolute value of a slope of the lower tail is 0.1 or more and 3 or less.

Abstract: Provided is a semiconductor apparatus, wherein a doping concentration distribution in the buffer region has a deepest slope where a doping concentration monotonically decreases to a position where it comes in contact with the drift region in a direction from the lower surface of the semiconductor substrate toward an upper surface, a hydrogen chemical concentration distribution in the buffer region includes in a first depth range provided with the slope: a first decrease portion where a hydrogen chemical concentration decreases toward the upper surface side; a second decrease portion located closer to the upper surface side than the first decrease portion is and where the chemical concentration decreases; and an intermediate portion arranged between the first and second decrease portions, and the intermediate portion has: a flat portion where the distribution is uniform; a peak in a slope of the chemical concentration; or a kink portion of the chemical concentration.

Abstract: Provided is a semiconductor device including: a buffer region having a doping concentration higher than a bulk donor concentration; a first low-concentration hydrogen peak in the buffer region; a second low-concentration hydrogen peak in the buffer region closer to a lower surface than the first low-concentration hydrogen peak; a high-concentration hydrogen peak in the buffer region closer to the lower surface than the second low-concentration hydrogen peak, the high-concentration hydrogen peak having a hydrogen chemical concentration higher than that of the second low-concentration hydrogen peak; and a flat region including a region between the two low-concentration hydrogen peaks and a region including the second low-concentration hydrogen peak, and having a doping concentration higher than a bulk donor concentration, an average value of the doping concentration being equal to or smaller than a local minimum value of a doping concentration between the second low-concentration hydrogen peak and the high-conc