Low voltage device in a high voltage substrate

US5286992A · kind A · utility

Assignee

• Actel Corporation · US

Inventors

• Michael G. Ahrens · Sunnyvale, US
• Douglas C. Galbraith · Fremont, US
• Abdelshafy A. Eltoukhy · San Jose, US

Key dates

• Filing date: Mar 29, 1993
• Grant date: Feb 15, 1994
• Expiry date: Mar 29, 2013

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S257/901

Abstract

A semiconductor or substrate of a first conductivity type includes a well structure of a second conductivity type formed therein. A first low voltage MOS transistor includes spaced apart source and drain regions of the first conductivity type in the well. A first transistor gate lies above a channel region which is disposed between the source and drain regions of the first low voltage MOS transistor and is separated therefrom by a gate dielectric having a first thickness. A second high voltage transistor includes spaced apart source and drain regions of the first conductivity type in the well. A second transistor gate lies above a channel region which is disposed between the source and drain regions of the second high voltage transistor and is separated therefrom by a gate dielectric having a second thickness which is greater than the thickness of the gate dielectric of the first low voltage MOS transistor. A first contact diffusion, having the same conductivity type as the well, is located at the edge of the well closest to the first low voltage transistor, and is connected to a source of voltage. A second contact diffusion, having the same conductivity type as the well, is locate…