Electrostatic discharge protection device

An electrostatic discharge protection device comprising:

• a substrate of a first conductivity type;
• a first well formed on the substrate and having the first conductivity type;
• a second well formed on the substrate surrounding the first well in a plan view, the second well having a second conductivity type;
• a first diffusion region and a second diffusion region formed on the first well and having the second conductivity type;
• a third diffusion region formed on the first well surrounding the first diffusion region and the second diffusion region in the plan view, the third diffusion region having the first conductivity type;
• a fourth diffusion region formed on the second well surrounding the third diffusion region in the plan view, the fourth diffusion region having the first conductivity type;
• and
• a fifth diffusion region formed on the second well surrounding the fourth diffusion region in the plan view, the fifth diffusion region having the second conductivity type,
• wherein the fourth diffusion region and the fifth diffusion region are connected to a first electrode, and the first diffusion region to the third diffusion region are connected to a second electrode.

An electrostatic discharge protection device comprising:

• a first well formed on a substrate and having a first conductivity type;
• a second well formed on the substrate surrounding the first well in a plan view, the second well having a second conductivity type;
• a first diffusion region and a second diffusion region formed on the first well and having the second conductivity type;
• a third diffusion region formed on the first well surrounding the first diffusion region and the second diffusion region in the plan view, the third diffusion region having the first conductivity type;
• a fourth diffusion region formed on the second well surrounding the third diffusion region in the plan view, the fourth diffusion region having the first conductivity type;
• a fifth diffusion region formed on the second well surrounding the fourth diffusion region in the plan view, the fifth diffusion region having the second conductivity type;
• a third well formed on the substrate and having the first conductivity type;
• a fourth well formed on the substrate surrounding the third well in the plan view, the fourth well having the second conductivity type;
• a sixth diffusion region and a seventh diffusion region formed on the third well and having the second conductivity type;
• an eighth diffusion region formed on the third well surrounding the sixth diffusion region and the seventh diffusion region in the plan view, the eighth diffusion region having the first conductivity type;
• a ninth diffusion region formed on the fourth well surrounding the eighth diffusion region in the plan view, the ninth diffusion region having the first conductivity type;
• and
• a tenth diffusion region formed on the fourth well surrounding the ninth diffusion region in the plan view, the tenth diffusion region having the second conductivity type,
• wherein the first diffusion region, the second diffusion region, the third diffusion region, the ninth diffusion region, and the tenth diffusion region are electrically connected to each other, and
• wherein the fourth diffusion region and the fifth diffusion region are connected to a first electrode, and the sixth diffusion region and the seventh diffusion region are connected to a second electrode.