Dual direction ESD clamp based on snapback NMOS cell with embedded SCR

US7394133B1 · kind B1 · utility

Assignee

• NATIONAL SEMICONDUCTOR CORPORATION · US

Inventors

• Vladislav Vashchenko · Palo Alto, US
• Peter J. Hopper · San Jose, US
• Philipp Lindorfer · San Jose, US

Key dates

• Filing date: Aug 31, 2005
• Grant date: Jul 1, 2008
• Expiry date: Aug 31, 2025

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/126

Abstract

In an ESD protection structure, dual direction ESD protection is provided by forming an n-well isolation ring around an NMOS device so that the p-well in which the NMOS drain is formed is isolated from the underlying p-substrate by the n-well isolation ring. By forming the n-well isolation ring the p-n-p-n structure of an embedded SCR for reverse ESD protection is provided. The width of the n-well isolation ring and its spacing from the NMOS drain are adjusted to provide the desired SCR parameters.