Electrostatic discharge protection device

1. An electrostatic discharge (ESD) protection device comprising:

an active well having a first conductive type;

a gate formed over the active well;

a source having a second conductive type formed in the active well at one side of the gate;

a drain having the second conductive type formed in the active well at the other side of the gate;

a butted region including impurities of the first conductive type formed in the active well between the gate and the source;

a diode region having the first conductive type formed in the active well to make contact with the drain; and

a first peripheral well having the second conductive type formed under the diode region,

wherein the gate, the source and the active well are electrically connected with a ground terminal, and the diode region is electrically connected with a pad to which a bias is applied.

2. The ESD protection device of claim 1 , wherein a width of the butted region is expanded to control a holding voltage.

3. The ESD protection device of claim 1 , further comprising a second peripheral well having the second conductive type formed at an edge portion of the active well.

4. The ESD protection device of claim 3 , further comprising a first well contact region having the second conductive type formed in the second peripheral well.

5. The ESD protection device of claim 3 , further comprising a semiconductor substrate in which the active well, the first peripheral well and the second peripheral well are formed; and a deep well having the second conductive type formed in the semiconductor substrate, the deep well making contact with bottom surfaces of the first peripheral well, the second peripheral well and the active well.

6. The ESD protection device of claim 3 ,

further comprising a semiconductor substrate in which the active well, the first peripheral well and the second peripheral well are formed; and a buried layer having the second conductive type formed in the semiconductor substrate, the buried layer making contact with a bottom surface of the second peripheral well, and the buried layer spaced apart from bottom surfaces of the active well and first peripheral well.

7. The ESD protection device of claim 1 , further comprising an active well contact region formed in the active well to provide the active well with a voltage.

8. The ESD protection device of claim 1 , further comprising a silicide layer formed on the source and the active well electrically connected with the ground terminal, and the diode region electrically connected with the pad,

wherein the diode region is covered by the silicide layer, and

wherein the butted region and the drain are exposed from the silicide layer.

9. The ESD protection device of claim 1 , further comprising:

a resistance connected between the gate and the source; and

a capacitor connected between the gate and the pad.

10. The ESD protection device of claim 1 , further comprising:

a semiconductor substrate in which the active well is formed;

a deep well having the second conductive type in the semiconductor substrate, the deep well having a set length and formed inside the semiconductor substrate to be spaced apart from a surface of the semiconductor substrate by a first depth; and

a pair of second peripheral wells formed to be contacted on both sides of the deep well and the pair of second peripheral wells having the second conductive type, wherein the first peripheral well is formed between the pair of the second peripheral wells, thereby dividing the active well into a first active well and a second active well.

11. The ESD protection device of claim 10 , wherein the gate, the source, the butted region and the drain are symmetrically formed in the first and second active wells positioned on both sides of the diode region and the first peripheral well.

12. The ESD protection device of claim 10 , wherein a first parasitic thyristor is formed between the diode region, the first peripheral well, the first active well and the drain which are formed in the first active well, and the butted region formed in the first active region; and

a second parasitic thyristor is formed between the diode region, the first peripheral well, the second active well and the drain which are formed in the second active well, and the butted region formed in the second active region.

13. The ESD protection device of claim 1 , wherein the first conductive type is a selected one of a n-type and a p-type, and the second conductive type is opposite to the first conductive type.

14. An electrostatic discharge (ESD) protection device comprising:

a semiconductor substrate;

a P well formed in the semiconductor substrate;

a first N well formed in an edge portion of the P well;

a second N well formed in the P well to divide the P well into a first region and a second region;

a gate formed over the first and second regions;

an N type source formed in the first and second regions at one side of the gate;

N type drains formed in the first and second regions between the gate and the second N well;

a P type diode region formed in the second N well between the drains;

a P type butted region formed between the gate and the source;

a P well contact region formed in the P well;

an N well contact region formed in the first N well; and

a silicide layer selectively formed on the source, the diode region, the P well contact region and the N well contact region.

15. The ESD protection device of claim 14 , further comprising a deep well formed on a bottom surface of the semiconductor substrate, the deep well making contact with bottom surfaces of the first N well and the P well.

16. The ESD protection device of claim 14 , further comprising an N type buried layer making contact with a bottom surface of the first N well and spaced apart from a bottom surface of the P well.

17. The ESD protection device of claim 14 , further comprising a first conductive line for electrically connecting the gate, the source and the P well with a ground terminal.

18. The ESD protection device of claim 14 , further comprising a second conductive lien for electrically connecting the diode region and the N well contact region with a pad.

19. The ESD protection device of claim 17 , further comprising:

a resistance connected between the gate and the source; and

a capacitor connected between the gate and the pad.