Patent ID: 7221237

Claim:
A frequency tunable device comprising: a substrate; a capacitor structure supported by said substrate and including a ferroelectric film made from a ferroelectric material exhibiting a paraelectric phrase and having a formula of Pb 1−x Ba x ZrO 3 , where x is a positive number greater than 0.3 and less than 0.6, and first and second electrodes formed on said ferroelectric film; and a dielectric film sandwiched between said substrate and said ferroelectric film and made from a material selected from the group consisting of TiO X , Ta 2 O 5 , (1−x) ZrO 2−x Y 2 O 3 , and Bi 4 Ti 3 O 12 , wherein the dielectric constant of said ferroelectric film varies with a voltage applied to said first and second electrodes.