Lightly doped drain ballast resistor

US5498892A · kind A · utility

Assignee

• NCR Corporation · US

Inventors

• John D. Walker · Colorado Springs, US
• Samuel C. Gioia · Colorado Springs, US

Key dates

• Filing date: Sep 29, 1993
• Grant date: Mar 12, 1996
• Expiry date: Sep 29, 2013

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D89/911

Abstract

A field effect transistor with improved electrostatic discharge (ESD) protection has a source, a channel underlying a gate electrode and a drain. The drain includes a lightly doped ballast resistor extending across the width of the drain and separating two other drain sub-regions. One drain sub-region is located between the ballast resistor and the channel, the other drain sub-region is opposite the resistor and connected to an exterior device. The ballast resistor laterally distributes current along the width of the drain during an ESD pulse, which reduces local peak current density and reduces damage.