Electrostatic discharge protective device

An electrostatic discharge protection device, comprising an electrostatic discharge protection unit, wherein the electrostatic discharge protection unit comprises:

• a P-type substrate;
• a P-type epitaxial layer disposed on the P-type substrate;
• an N-type buried layer disposed between the P-type substrate and the P-type epitaxial layer;
• a first N-type well disposed on the N-type buried layer and inside the P-type epitaxial layer;
• a first P-type well disposed on the N-type buried layer and inside the P-type epitaxial layer, the first P-type well being adjacent to the first N-type well;
• a second N-type well disposed on the N-type buried layer and inside the P-type epitaxial layer, and adjacent to the first P-type well;
• an ESD doped injection layer disposed in the first P-type well and the first N-type well;
• a first N+ region and a first P+ region disposed in the ESD doped injection layer;
• and
• a second N+ region and a second P+ region disposed outside the ESD doped injection layer, wherein the second N+ region and the second P+ region are disposed in the first N-type well or the first P-type well with a conductivity type opposite to the ESD doped injection layer.