Electrostatic discharge protection structure

An electrostatic discharge (ESD) protection structure, comprising:

• a semiconductor substrate;
• a first n-type well region disposed in the semiconductor substrate;
• a p-type well region disposed in the semiconductor substrate and located adjacent to the first n-type well region;
• a first p-type doped region disposed in the semiconductor substrate and located above the first n-type well region in a vertical direction;
• a second p-type doped region disposed in the semiconductor substrate and located above the p-type well region in the vertical direction;
• and
• an isolation structure disposed in the semiconductor substrate, wherein a first portion of the isolation structure is located between the first p-type doped region and the second p-type doped region in a first horizontal direction, an edge of the first n-type well region is located under the first portion of the isolation structure in the vertical direction, and a distance between the first p-type doped region and the edge of the first n-type well region in the first horizontal direction is less than a length of the first portion of the isolation structure in the first horizontal direction.