Electrostatic discharge (esd) guard ring protective structure
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsTsung-Che TSAI, Jam-Wem LEE, Yi-Feng CHANG
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Abstract
An ESD protection circuit includes a MOS transistor of a first type, a MOS transistor of a second type, an I/O pad, and first, second, and third guard rings of the first, second, and first types, respectively. The MOS transistor of the first type has a source coupled to a first node having a first voltage, and a drain coupled to a second node. The MOS transistor of the second type has a drain coupled to the second node, and a source coupled to a third node having a second voltage lower than the first voltage. The I/O pad is coupled to the second node. The first, second, and third guard rings are positioned around the MOS transistor of the second type.
Claims20
An electrostatic discharge (ESD) protection circuit comprising:
- a MOS transistor of a first type including a source coupled to a first node having a first voltage, and a drain coupled to a second node;
- a MOS transistor of a second type including a drain coupled to the second node, and a source coupled to a third node having a second voltage lower than the first voltage;
- an input/output (I/O) pad coupled to the second node;
- a first guard ring of the first type;
- a second guard ring of the second type;
- and
- a third guard ring of the first type;
- wherein the first, second, and third guard rings are positioned around the MOS transistor of the second type.
An electrostatic discharge (ESD) protection circuit structure comprising:
- a first diffusion region of a first type formed in a first well of the first type;
- a second diffusion region of the first type formed in the first well of the first type;
- a first diffusion region of a second type formed in a first well of the second type, wherein the first well of the second type is formed in the first well of the first type;
- and
- a MOS transistor of the second type including a drain formed by a second diffusion region of the second type formed in a second well of the second type bordering the first well of the first type.
An electrostatic discharge (ESD) protection circuit comprising:
- a MOS transistor of a first type including a source coupled to a first voltage source and a drain coupled to an input/output (I/O) pad, wherein the drain and the source of the MOS transistor of the first type are formed by a first diffusion region of the first type and a first diffusion region of a second type, respectively, and the first diffusion region of the first type and the first diffusion region of the second type are formed in a first well of the first type and a first well of the second type, respectively;
- a MOS transistor of the second type including a drain coupled to the I/O pad and a source coupled to a second voltage source having a lower voltage than a voltage of the first voltage source, wherein the source and the drain of the MOS transistor of the second type are formed by a second diffusion region of the first type and a second diffusion region of the second type, respectively, and the second diffusion region of the first type and the second diffusion region of the second type are formed in a second well of the first type and a second well of the second type, respectively;
- a first guard ring including a third diffusion region of the first type formed in a third well of the first type bordering the second well of the second type;
- a second guard ring including a third diffusion region of the second type formed in a third well of the second type;
- and
- a third guard ring including a fourth diffusion region of the first type formed in the third well of the first type;
- wherein the second guard ring is positioned between the first and third guard rings.
Dependencies are inferred from the claim text.