Electrostatic discharge protection device

An electrostatic discharge protection device, comprising:

• a substrate;
• a first doping region of a first conductivity type on the substrate;
• a second doping region of the first conductivity type on the substrate and spaced apart from the first doping region;
• an epitaxial layer of a second conductivity type between the first doping region and the second doping region;
• a first well region of the second conductivity type on the first doping region;
• a second well region of the first conductivity type on the first doping region and spaced apart from the first well region;
• a third well region of the second conductivity type on the epitaxial layer;
• a first diffusion region of the first conductivity type on the second well region;
• a second diffusion region of the second conductivity type on the third well region;
• a third diffusion region of the first conductivity type on the second doping region;
• and
• a fourth diffusion region on the first well region,
• wherein the first diffusion region and the fourth diffusion region are electrically coupled, and
• wherein a first doping concentration of the third well region is greater than a second doping concentration of the epitaxial layer.

An electrostatic discharge protection device, comprising:

• a substrate;
• a first doping region of a first conductivity type on the substrate;
• a second doping region of the first conductivity type on the substrate and spaced apart from the first doping region;
• an epitaxial layer of a second conductivity type between the first doping region and the second doping region;
• a first well region of the second conductivity type on the first doping region;
• a second well region of the first conductivity type on the first doping region and spaced apart from the first well region;
• a first drift region of the second conductivity type on the epitaxial layer;
• a third well region of the second conductivity type on the first drift region and forming a junction interface with the second well region;
• a first diffusion region of the first conductivity type on the second well region;
• a second diffusion region of the second conductivity type on the third well region;
• a third diffusion region of the first conductivity type on the second doping region;
• and
• a fourth diffusion region of the second conductivity type on the first well region,
• wherein the first diffusion region and the fourth diffusion region are electrically coupled,
• wherein a first doping concentration of the first drift region is less than a second doping concentration of the third well region,
• wherein the first doping concentration of the first drift region is larger than a third doping concentration of the epitaxial layer, and
• wherein a fourth doping concentration of the first well region is greater than the third doping concentration of the epitaxial layer.