UNIDIRECTIONAL ESD PROTECTION WITH BURIED BREAKDOWN THYRISTOR DEVICE

An electrostatic discharge protection device includes a substrate, first and second emitter regions disposed in the substrate, laterally spaced from one another on a side of the substrate, and having opposite conductivity types, and first and second base regions having opposite conductivity types and in which the first and second emitter regions are disposed in a thyristor arrangement, respectively. The first base region includes a buried doped layer that extends under the second base region. Each of the buried doped layer and the second base region includes a respective non-uniformity in dopant concentration profile. A spacing between the buried doped layer and the second base region at the respective non-uniformities establishes a breakdown trigger voltage for the thyristor arrangement.