Semiconductor structures, static random access memories, and fabrication methods thereof

A method for fabricating a semiconductor structure, comprising:

• providing a base substrate;
• forming two first fin structures and an initial isolation structure on the base substrate, wherein the two first fin structures are parallel to each other, a top surface of the initial isolation structure is lower than top surfaces of the two first fin structures, the initial isolation structure includes a first region, located between the two first fin structures, and two second regions, each being in contact with a first fin structure and located on one side of the first fin structure in opposite to the first region;
• implanting doping ions into a top of the initial isolation structure formed in the first region adjacent to the two first fin structures;
• forming an isolation structure by removing a portion of the initial isolation structure, wherein a removal rate of the initial isolation structure formed in the first region adjacent to the two first fin structures is smaller than a removal rate of the initial isolation structure formed in the two second regions adjacent to the two first fin structures, and a top surface of the isolation structure formed in the first region adjacent to the two first fin structures is higher than the top surface of the isolation structure formed in the two second regions;
• and
• forming a plurality of source/drain openings in the isolation structure by removing a portion of the two first fin structures.