Ferroelectric memory device and manufacturing method thereof

The present disclosure relates generally to ferroelectric memory devices and methods of manufacturing the same. Ferroelectric stacks that can improve retention performance of ferroelectric memory devices are disclosed herein. An exemplary ferroelectric stack has a stack of ferroelectric switching layers (FSL) disposed between a first electrode and a second electrode. The ferroelectric stack includes a barrier layer disposed between the first FSL and the second FSL, wherein a first crystal condition of the barrier layer is different from a second crystal condition of the first FSL and/or the second FSL. In some embodiments, the first crystal condition is an amorphous phase and the second crystal condition is an orthorhombic phase. In some embodiments, the first FSL and/or the second FSL include a first metal oxide and the barrier layer includes a second metal oxide. The ferroelectric stack may be a ferroelectric capacitor, part of a transistor, and/or connected to a transistor in a ferroelectric memory device