Semiconductor structure and fabrication method thereof

A semiconductor structure, comprising:

• a first type substrate;
• a first type body doped region on the first type substrate;
• a first type heavily-doped region on the first type body doped region;
• a second type well region on the first type substrate;
• a plurality of second type bar regions between the second type well region and the first type body doped region, wherein the first type body doped region, the second type well region, and each of the second type bar regions are separated to one another by the first type substrate;
• a second type heavily-doped region on the second type well region;
• an isolation structure on the first type substrate between the first type heavily-doped region and second type heavily-doped region;
• and
• a gate structure on the first type substrate between the first type heavily-doped region and isolation structure.

A semiconductor structure, comprising:

• a first type substrate;
• a first type body doped region on the first type substrate;
• a first type heavily-doped region on the first type body doped region;
• a second type well region on the first type substrate;
• a diffused second type well region between the second type well region and first type body doped region and adjoined to the second type well region, wherein a second type impurity concentration of the diffused second type well region is lower than a second type impurity concentration of the second type well region;
• a second type heavily-doped region on the second type well region;
• an isolation structure on the diffused second type well region;
• and
• a gate structure on the first type substrate between the first type heavily-doped region and isolation structure.