Semiconductor structure and fabrication method thereof

Semiconductor structure is provided. The semiconductor structure includes a substrate including device regions and an isolation region located adjacent to and between the device regions; a fin on the substrate; gate structures across the fin at the device regions; source/drain doped regions in the fin at two sides of each of the gate structures; a first opening in the fin at the isolation region; and an insulation structure located in the first opening. Two opposite sidewalls of the first opening are respectively in contact with the source/drain doped regions at adjacent device regions. A top surface of the insulation structure is flush with or higher than top surfaces of the source/drain doped regions.