Semiconductor device manufacturing method

A semiconductor device manufacturing method, comprising:

• providing a semiconductor structure, wherein the semiconductor structure comprises a semiconductor substrate, a first doped region in the semiconductor substrate and a first gate structure on the first doped region;
• forming a source and a drain in the first doped region on two opposite sides of the first gate structure;
• and
• implanting dopants to the source and the drain by an ion implantation process,
• wherein the ion implantation process results in a first implanted region in the source, results in a second implanted region in the drain, results in a first intervening region in the source and between the first implanted region and the first gate structure after the ion implantation process, and results in a second intervening region in the drain and between the second implanted region and the first gate structure after the ion implantation process,
• wherein a boundary between the first intervening region and the first implanted region is positioned closer to the first gate structure than a boundary between the second intervening region and the second implanted region is, and
• wherein an implantation concentration of the first implanted region is equal to an implantation concentration of the second implanted region and is greater than each of an implantation concentration of the first intervening region and an implantation concentration of the second intervening region.