RC-triggered semiconductor controlled rectifier for ESD protection of signal pads

US8891212B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Michel J. Abou-Khalil · South Burlington, US
• Robert J. Gauthier, Jr. · South Burlington, US
• Tom C. Lee · South Burlington, US
• Junjun Li · Williston, US
• Souvick Mitra · South Burlington, US
• Christopher S. Putnam · South Burlington, US

Key dates

• Filing date: Apr 5, 2011
• Grant date: Nov 18, 2014
• Expiry date: Feb 18, 2033

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T29/49002
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

RC-trigger circuits for a semiconductor controlled rectifier (SCR), methods of providing electrostatic discharge (ESD) protection, and design structures for a RC-trigger circuit. The RC-trigger circuit is coupled to an input/output (I/O) signal pad by an isolation diode and is coupled to a power supply voltage by a power supply diode. Under normal operating conditions, the isolation diode is reverse biased, isolating the RC-trigger circuit from the input/output (I/O) pad, and the power supply diode is forward biased so that the RC-trigger circuit is supplied with power. The isolation diode may become forward biased during ESD events while the chip is unpowered, causing the RC-trigger circuit to trigger an SCR configured protect the signal pad from ESD into a conductive state. The power supply diode may become reverse biased during the ESD event, which isolates the power supply rail from the ESD voltage pulse.