Static random access memory (SRAM) and forming method thereof

A forming method for a static random access memory (SRAM), comprising:

• providing a semiconductor substrate including memory cell regions, each memory cell region including a transmission region, a pull-down region, and a pull-up region including a pull-up fin cutting region;
• forming first fins on the transmission region and the pull-down region;
• forming second initial fins on the pull-up region, the second initial fins extending to the pull-up fin cutting region;
• forming initial gate structures across the first fins and the second initial fins, the pull-up fin cutting region being on a side of the initial gate structures;
• forming a dielectric layer covering sidewalls of the initial gate structures on the semiconductor substrate, the first fins and the second initial fins;
• forming a mask layer on the dielectric layer and the initial gate structures, the mask layer having a mask opening on the pull-up fin cutting region and extending from an extension direction of the second initial fins to the initial gate structures;
• forming a first cutting layer in the initial gate structures at a bottom of the mask opening, so that transmission gate structures and pull gate structures on both sides of the first cutting layer are formed from the initial gate structures, the transmission gate structures being on the transmission region;
• and
• forming a second cutting layer on the pull-up fin cutting region, and in the dielectric layer at the bottom of the mask opening and in the second initial fins, and forming second fins on a side of the second cutting layer from the second initial fins, the first cutting layer being on top surfaces of the second fins.