Electrostatic discharge device

Abstract

An electrostatic discharge device is coupled between a first input / output pad and a second input / output pad, and includes first to fifth bijunction transistors (BJTs) and a metal-oxide-semiconductor (MOSFET). The collector / emitter electrodes of the first and fifth BJTs are coupled to the emitter / collector electrodes of a third BJT and the first input / output pad. The base electrode and collector / emitter electrode of the second BJT are coupled to the emitter / collector electrodes of the first BJT, the base electrode and collector / emitter electrodes of the third BJT, the gate electrode and source / drain electrode of the MOSFET, and the second input / output pad. The emitter / collector electrode of the second BJT is coupled to the base electrode of the first BJT. The base electrode of the fourth BJT is coupled to the base electrode of the third BJT and the emitter / collector electrodes of the fifth BJT. The emitter / collector electrode of the fourth BJT is coupled to the emitter / collector electrodes of the third BJT. The collector / emitter electrode of the fourth BJT is coupled to the base electrodes of the first and fifth BJTs.

Claims

1. An electrostatic discharge device coupled between a first input / output pad and a second input / output pad, comprising: A first dual-cell transistor includes a first base electrode, a first collector / emitter electrode, and a first emitter / collector electrode, the first collector / emitter electrode being coupled to the first input / output pad; a second dual-cell transistor includes a second base electrode, a second collector / emitter electrode, and a second emitter / collector electrode, the second base electrode being coupled to the first emitter / collector electrode, the second emitter / collector electrode being coupled to the first base electrode, and the second collector / emitter electrode being coupled to the second base electrode and the second input / output pad; a third dual-cell transistor includes a third base electrode, a third collector / emitter electrode, and a third emitter / collector electrode, the third emitter / collector electrode being coupled to the first input / output pad, and the third collector / emitter electrode being coupled to the second input / output pad; A fourth bipolar transistor includes a fourth base electrode, a fourth collector / emitter electrode, and a fourth emitter / collector electrode, wherein the fourth base electrode is coupled to the third base electrode and the second base electrode, the fourth emitter / collector electrode is coupled to the third emitter / collector electrode, and the fourth collector / emitter electrode is coupled to the first base electrode; a fifth bipolar transistor includes a fifth base electrode, a fifth collector / emitter electrode, and a fifth emitter / collector electrode, wherein the fifth base electrode is coupled to the first base electrode, the fifth emitter / collector electrode is coupled to the third base electrode, and the fifth collector / emitter electrode is coupled to the first input / output pad; and a metal-oxide-semiconductor field-effect transistor includes a gate electrode, a drain / source electrode, and a source / drain electrode, wherein the gate electrode and the source / drain electrode are coupled to the second input / output pad, and the drain / source electrode is coupled to the third base electrode.

2. The electrostatic discharge device as claimed in claim 1, wherein the first bipolar transistor and the fifth bipolar transistor system are NPN type bipolar transistors, and the second bipolar transistor, the third bipolar transistor and the fourth bipolar transistor system are PNP type bipolar transistors.

3. The electrostatic discharge device as claimed in claim 2, wherein the metal-oxide-semiconductor system is an N-type metal-oxide-semiconductor.

4. The electrostatic discharge device as described in claim 3, further comprising: A wire electrically connects the first base electrode and the second base electrode.

5. An electrostatic discharge device, comprising: A substrate having a first conductivity type; A deep well region is disposed within the substrate and has a second conductivity type; A first well region is disposed on the substrate and has the first conductivity type; a first doped region is disposed within the first well region and has the second conductivity type; a second doped region is disposed within the first well region and has the second conductivity type; a gate structure is disposed on the first well region and located between the first doped region and the second doped region; a second well region is disposed on the deep well region and has the first conductivity type; a third well region has the second conductivity type and surrounds the second well region to separate the first well region and the second well region; a third doped region is disposed within the second well region and has the second conductivity type; a fourth well region is disposed on the deep well region and has the first conductivity type; and a fourth doped region is disposed within the fourth well region and has the first conductivity type; wherein: the third well region is located on the deep well region and surrounds the fourth well region to separate the first well region and the fourth well region, and the first conductivity type is relative to the second conductivity type.

6. The electrostatic discharge device as described in claim 5, further comprising: A gap separates the second doped region from the third doped region.

7. The electrostatic discharge device as described in claim 5, further comprising: A fifth doped region separates the second doped region from the third doped region and has the first conductivity type.

8. The electrostatic discharge apparatus as claimed in claim 7, wherein the fifth doped region overlaps with a portion of the second well region and a portion of the third well region.

9. The electrostatic discharge device as described in claim 8, further comprising: A first isolation structure is provided to prevent the surface metal layer of the third doped region from connecting to the surface metal layer of the fifth doped region.

10. The electrostatic discharge apparatus as claimed in claim 9, wherein the first isolation structure is located between the surface metal layer of the third doped region and the surface metal layer of the fifth doped region.

11. The electrostatic discharge device as claimed in claim 9, wherein the first isolation structure extends into the second well region.

12. The electrostatic discharge device as described in claim 9, further comprising: A second isolation structure overlaps the second doped region and the fourth doped region.

13. The electrostatic discharge apparatus as claimed in claim 12, wherein the fourth doped region is electrically connected to the third doped region.

14. The electrostatic discharge device as claimed in claim 13, wherein the second isolation structure overlaps the gate structure.

15. The electrostatic discharge device as claimed in claim 13, wherein the second isolation structure extends into the third well region and the fourth well region.

16. The electrostatic discharge device as described in claim 7, further comprising: A connection structure electrically connects the second doped region and the fifth doped region.

17. The electrostatic discharge device as claimed in claim 5, wherein the region of the gate structure mapped onto the substrate does not contact the region of the third well zone mapped onto the substrate.

18. The electrostatic discharge device as claimed in claim 5, wherein the gate structure is electrically connected to the first doped region and the third doped region is electrically connected to the fourth doped region.

19. The electrostatic discharge device as claimed in claim 18, wherein the first conductivity type is P-type and the second conductivity type is N-type.

20. The electrostatic discharge device as claimed in claim 19, wherein the region of the gate structure mapped onto the substrate contacts the region of the third well region mapped onto the substrate.

Images