Microelectromechanical System (MEMS) devices and related fabrication methods. A piezoelectric stack is formed on a substrate and is separated from the substrate by a dielectric layer. The piezoelectric stack is formed that includes first and second piezoelectric layers with a first electrode below the first piezoelectric layer, as well as a contact pad and a second electrode between the first and second piezoelectric layers. A first contact is formed that extends through the piezoelectric layers and contact pad to the first electrode. A second contact is formed that extends through the second piezoelectric layer to the second electrode. The contact pad prevents an interface to form between the first and second piezoelectric layers in the contact opening, thus preventing corrosion of the piezoelectric layers during contact formation process.