Semiconductor structure with isolation structures in doped region and fabrication method thereof

A fabrication method for a semiconductor structure,

• comprising:
• providing a substrate including a first doped region and a second doped region adjacent to the first doped region in the substrate, wherein the first doped region is doped with first doping ions and the second doped region is doped with second doping ions having a conductivity type opposite to a conductivity type of the first doping ions;
• forming a plurality of first isolation structures in the second doped region, wherein the plurality of first isolation structures are discrete from each other;
• forming a third doped region in the second doped region between each two adjacent first isolation structures of the plurality of first isolation structures and under the plurality of first isolation structures, each two adjacent first isolation structures of the plurality of first isolation structures being isolated from each other by the third doped region, wherein the third doped region is doped with third doping ions and the third doping ions have a conductivity type opposite to the conductivity type of the second doping ions;
• forming a gate structure on a portion of a surface of the first doped region, on a portion of a surface of the second doped region, and on a portion of surfaces of the plurality of first isolation structures;
• forming a source region in the first doped region at a side of the gate structure;
• and
• forming a drain region in the second doped region at another side of the gate structure, wherein a portion of the plurality of first isolation structures is located between the gate structure and the drain region.