Semiconductor device and manufacturing method of semiconductor device

A semiconductor device comprising:

• a semiconductor substrate having an upper surface and a lower surface, and containing a bulk donor;
• a buffer region of a first conductivity type which is disposed on the lower surface side of the semiconductor substrate and contains a hydrogen donor, and in which a doping concentration distribution of the semiconductor substrate in a depth direction has a first doping concentration peak with a first hydrogen chemical concentration peak;
• an impurity chemical concentration peak is disposed on an upper surface side of the semiconductor substrate, wherein a doping concentration at a position of the impurity chemical concentration peak is less than an impurity chemical concentration of the impurity chemical concentration peak;
• a high-concentration region of the first conductivity type including the impurity chemical concentration peak that is located in the upper surface side of the semiconductor substrate in the high-concentration region which is in contact with the first doping concentration peak of the buffer region contains a hydrogen donor, and has a donor concentration higher than a bulk donor concentration;
• and
• a lower surface region of the first conductivity type or a second conductivity type which is disposed between the buffer region and the lower surface of the semiconductor substrate, and has a doping concentration higher than the high-concentration region, wherein
• at least in a uniform region, a hydrogen chemical concentration monotonically decreases from the buffer region at least up to the impurity chemical concentration peak,
• a doping concentration distribution of the uniform region is within a range in which a value of the doping concentration distribution is within ±10% of an average concentration of the doping concentration distribution in a first range in the uniform region, and
• when a length of the high-concentration region in the depth direction is set to ZL and a center between the shallowest doping concentration peak and the impurity chemical concentration peak in the depth direction is set to Z12C, the first range is a section with a length of 0.5ZL including the center Z12C, the length of the first range is set between two points separated by 0.25ZL from the center Z12C between Z1 and Z2, toward the first depth position Z1 side and the second depth position Z2 side, and
• in the high-concentration region, a hydrogen chemical concentration monotonically decreases from the buffer region beyond the impurity chemical concentration peak toward the upper surface.