Semiconductor structure and method for manufacturing the same

A method for manufacturing a semiconductor structure, comprising:

• forming a dummy gate, spacers, and an insulating layer on a semiconductor substrate, wherein said dummy gate is surrounded by said spacers, and said insulating layer adjoins said spacers and exposes said dummy gate;
• removing said dummy gate to form an opening;
• implanting a first dopant through said opening to form a super-steep retrograde island in said semiconductor substrate;
• forming an auxiliary mask layer in said opening, wherein said auxiliary mask layer covers at least sidewalls of said opening;
• implanting a second dopant through said opening in which said auxiliary mask layer is formed, said second dopant having a doping type opposite to said first dopant,
• wherein in the case where said auxiliary mask layer covers the sidewalls of said opening and exposes the bottom of said opening, a first counter doped region is formed in said semiconductor substrate by said second dopant;
• and
• wherein in the case where said auxiliary mask layer covers the sidewalls and the bottom of said opening, said second dopant is either blocked by said auxiliary mask layer or forms a second counter doped region in said super-steep retrograde island, and said second counter doped region has a doping concentration smaller than that of said first counter doped region.