Internal ESD protection circuit for semiconductor devices

US5751042A · kind A · utility

Assignee

• UNITED MICROELECTRONICS CORP. · TW

Inventor

• Ta-Lee Yu · Shanghai, CN

Key dates

• Filing date: Feb 15, 1996
• Grant date: May 12, 1998
• Expiry date: Feb 15, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D89/601

Abstract

An internal electrostatic discharge (ESD) protection circuit for semiconductor devices defines a structure for protecting adjacent n-channel devices. The first n-channel device includes a pair of n+ regions defining source and drain regions wherein the drain region is connected to a positive power supply terminal (V.sub.DD). The second, adjacent, n-channel device also includes a pair of n+ regions forming source and drain regions, respectively, wherein the source region of the second n-channel device is connected to a negative power supply terminal (V.sub.SS). The drain of the first n-channel device is laterally spaced, and isolated from the source of the second n-channel device by a thick field oxide region. The novel structure includes forming an N-conductivity type well that substantially overlaps the drain n+ region of the first n-channel device and extends toward the n+ region that forms the source of the second n-channel device. The N-well is doped to a lower density than the n+ regions, and further, is formed into the substrate to a depth that is substantially larger than the depth of the n+ regions. The N-well substantially increases the junction breakdown voltage of the de…