Electrically tunable device and a method relating thereto

US6563153B2 · kind B2 · utility

Assignee

• Telefonaktiebolaget LM Ericsson (Publ) · SE

Inventors

• Erland Wikborg · Danderyd, SE
• Zdravko Ivanov · Umeå, SE
• Peter Petrov · Partille, SE
• Spartak Gevorgian · Handen, SE

Key dates

• Filing date: Jun 20, 2001
• Grant date: May 13, 2003
• Expiry date: Jun 20, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/64

Abstract

A thin film ferroelectric varactor device comprising a substrate layer, a ferroelectric layer structure and an electrode structure is presented. The ferroelectric layer structure comprises a number of ferroelectric layers and a number of intermediate buffer layers arranged in an alternating manner. At least a first and a second layer of the ferroelectric layers have different Curie temperatures, i.e. the dielectric constant of the first ferroelectric layer has a maximum at a temperature which is different from the temperature at which the dielectric constant of the second ferroelectric layer has a maximum.