US Patent 11189611 Electrostatic discharge protection semiconductor device

An ESD protection semiconductor device includes a substrate. A gate set disposed on the substrate. A plurality of source fins and a plurality of drain fins having a first conductivity type are disposed in the substrate respectively at two sides of the gate set. A first doped fin is disposed in the substrate and positioned in between the source fins and spaced apart from the source fins. The first doped fin comprises a second conductivity type that is complementary to the first conductivity type. A second doped fin is formed in one of the drain fins and isolated from the one of the drain fins by an isolation structure. The second doped fin is electrically connected to the first doped fin.