US Patent 9478728 Piezoelectric devices

Piezoelectric devices are provided. A device can include a top electrode, a first piezoelectric layer having an upper surface disposed on a lower surface of the top electrode, a first center electrode having an upper surface disposed on a lower surface of the first piezoelectric layer, an insulating layer having an upper surface disposed on a lower surface of the first center electrode, a second center electrode having an upper surface disposed on a lower surface of the insulating layer, a second piezoelectric layer having an upper surface disposed on a lower surface of the second center electrode, and a bottom electrode having an upper surface disposed on a lower surface of the second piezoelectric layer. The insulating layer can be positioned substantially at a vertical center of the piezoelectric device. The first center electrode can be electrically connected to the second center electrode.