US 7,612,410 B1 · Trigger device for ESD protection circuit

Abstract

The present invention is a trigger device useful, for example, in triggering an SCR in an ESD protection circuit. Illustratively, an NMOS trigger device comprises a gate and heavily doped P and N regions in a P-well on opposite sides of the gate. A first N type source/drain extension and a first P-type pocket region extend from the P region toward the N region with the pocket region located under the source/drain extension and extending under the gate. A second N-type source/drain extension and a second P-type pocket region extend from the N region toward the P region with the pocket region located under the source/drain extension and extending under the gate. Preferably, the gate itself is heavily doped so that one half of the gate on the side adjacent the heavily doped P region is also heavily doped with dopants of P-type conductivity and the other half of the gate on the side adjacent the heavily doped N region is also heavily doped with dopants of N-type conductivity. Doping the gate increases the threshold voltage by about one Volt due to an increase in the work function on the source side of the gate.

Claims13

Dependent claims

A trigger device for an electrostatic discharge (ESD) protection circuit, said device comprising:

a substrate having a first conductivity type;
a gate on the substrate and insulated therefrom, said gate having a width and first and second sides;
a first heavily doped region in the substrate, said region extending for the width of the gate on its first side and having a first conductivity type;
a second heavily doped region in the substrate, said region extending for the width of the gate on its second side and having a second conductivity type;
a first source/drain extension in the substrate, said extension extending for the width of the gate and extending from the first heavily doped region toward the second heavily doped region and having a second conductivity type;
a second source/drain extension in the substrate, said extension extending for the width of the gate and extending from the second heavily doped region toward the first heavily doped region and having a second conductivity type;
a first pocket region located under the first source/drain extension and extending under the gate;
and
a second pocket region located under the second source/drain extension and extending under the gate, the first and second pocket regions having a first conductivity type.

6 more elements

An electrostatic discharge (ESD) protection circuit comprising:

a PNP transistor and an NPN transistor, each having an emitter, a base and a collector, with the collector of the PNP transistor connected to the base of the NPN transistor and the collector of the NPN transistor connected to the base of the PNP transistor, and
a trigger device connected between the emitter of one of the transistors and the base of the other transistor wherein the trigger device comprises:
a substrate having a first conductivity type;
a gate on the substrate and insulated therefrom, said gate having a width and first and second sides;
a first heavily doped region in the substrate, said region extending for the width of the gate on its first side and having a first conductivity type;
a second heavily doped region in the substrate, said region extending for the width of the gate on its second side and having a second conductivity type;
a first source/drain extension in the substrate, said extension extending for the width of the gate and extending from the first heavily doped region toward the second heavily doped region and having a second conductivity type;
a second source/drain extension in the substrate, said extension extending for the width of the gate and extending from the second heavily doped region toward the first heavily doped region and having a second conductivity type;
a first pocket region located under the first source/drain extension and extending under the gate;
and
a second pocket region located under the second source/drain extension and extending under the gate, the first and second pocket regions having a first conductivity type.

8 more elements

Dependencies are inferred from the claim text.

Trigger device for ESD protection circuit

Life of this patent

Trigger device for ESD protection circuit

Life of this patent

Abstract

Claims13