Controlled temperature coefficient thin-film circuit element

US4464646A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Kurt Burger · Friolzheim, DE
• Heinz Friedrich · Friolzheim, DE
• Heiko Gruner · Stuttgart, DE
• Karl-Otto Linn · Karlsruhe, DE
• Erich Zabler · Blankenloch, DE

Key dates

• Filing date: Jul 7, 1981
• Grant date: Aug 7, 1984
• Expiry date: Jul 7, 2001

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01C17/232
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

To form a temperature sensor, for example suitable in an automotive vehicle, to determine ambient temperatures, or to provide a temperature compensated thin-film circuit, for example for incorporation with an oscillator circuit, two stable thin-film layers are applied to a non-conductive substrate, the layers being capable of being etched. The overall temperature coefficient of resistance can be matched to a predetermined value by selective interconnection of at least two thin-film resistance elements formed by the thin films, of which one thin film resistance element for example comprises a nickel layer over a tantalum base, with a predetermined temperature coefficient of resistance, the other resistance element merely being the tantalum layer with essentially zero temperature coefficient of resistance, the overall temperature coefficient of resistance of the combination being determined by adjustment of the relative resistance values after measurement of the temperature coefficient of resistance of the nickel-tantalum layer to determine its actual temperature coefficient so that, in spite of tolerances in the manufacture of the thin films, interchangeable elements of highly accur…