N-channel MOS transistor

US4042945A · kind A · utility

Assignee

• Westinghouse Electric Company LLC · US

Inventors

• Hung C. Lin · Silver Spring, US
• Marvin H. White · Laurel, US

Key dates

• Filing date: Jul 14, 1975
• Grant date: Aug 16, 1977
• Expiry date: Jul 14, 1995

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/693

Abstract

An N-channel MOS transistor wherein two layers of different dielectric materials (e.g., silicon dioxide and silicon nitride) are used in conjunction with a P-doped silicon gate to permit the use of a higher resistivity P-type substrate. This enables a higher junction breakdown voltage and a higher threshold voltage without a reverse bias on the substrate due to an increase in the work function difference between the gate and substrate. Because of the lower concentration (i.e., higher resistivity) of the substrate, high frequency response is increased due to lower drain-source capacitance.