Shielded integrated circuit capacitor connected to a lateral transistor

US6198123A · kind A · utility

Assignee

• Cardiac Pacemakers, Inc. · US

Inventors

• William J. Linder · Golden Valley, US
• Robert S. Harguth · Ham Lake, US

Key dates

• Filing date: Aug 29, 1997
• Grant date: Mar 6, 2001
• Expiry date: Aug 29, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/68

Abstract

An integrated circuit (IC) capacitor offers reduced sensitivity to parasitic capacitance, reduced-size, and increased noise immunity, such as for use in digital-to-analog converters (DACs), analog-to-digital converters (ADCs), switched-capacitor filters, and other IC circuits. The capacitor includes a first polysilicon layer, a superjacent second polysilicon layer separated from the first polysilicon layer by an insulator, and an overlying metal layer separated from the second polysilicon layer by an insulator. The metal layer provides a shield that is connected to a known voltage, or to the first polysilicon layer. When connected to the first polysilicon layer, the overlying metal layer also provides additional parallel capacitance, thereby reducing the integrated circuit area of the capacitor. In one example, the overlying metal layer is a second metal layer that is also used, together with a first metal layer, for interconnecting IC components.