Silicon-controlled rectifiers for electrostatic discharge protection

A structure for a silicon-controlled rectifier, the structure comprising:

• a semiconductor substrate;
• a first well in the semiconductor substrate, the first well having a first conductivity type;
• a second well in the semiconductor substrate, the second well having a second conductivity type opposite to the first conductivity type;
• a first terminal including a first doped region that has a first portion in the first well, the first doped region having the second conductivity type;
• a second terminal including a second doped region that has a first portion in the first well and a third doped region in the second well, the second doped region having the second conductivity type, the third doped region having the first conductivity type, and the second doped region positioned in a lateral direction between the first doped region and the third doped region;
• and
• a fourth doped region in the second well, the fourth doped region having the first conductivity type, and the fourth doped region positioned in the lateral direction between the second doped region and the third doped region.

A method of forming a structure for a silicon-controlled rectifier, the structure comprising:

• forming a first well in a semiconductor substrate;
• forming a second well in the semiconductor substrate;
• forming a first terminal that includes a first doped region having a first portion in the first well;
• forming a second terminal that includes a second doped region having a first portion in the first well and a third doped region in the second well;
• and
• forming a fourth doped region in the first well,
• wherein the first well and the third doped region have a first conductivity type, the second well, the first doped region, the second doped region, and the fourth doped region have a second conductivity type opposite to the first conductivity type, and the second doped region is positioned in a lateral direction between the first doped region and the third doped region, and the fourth doped region is positioned in the lateral direction between the first doped region and the second doped region.