Morphotropic Phase Boundary Engineering via Heterostructure for Low-Voltage Ferroelectric Capacitors

Abstract

We investigated morphotropic phase boundary (MPB) engineering via heterostructure design to achieve low-voltage and fast-switching ferroelectric capacitors based on HfxZr1-xO2 (HZO). By integrating an MPB layer with a conventional ferroelectric HZO layer in a metal–ferroelectric–metal (MFM) structure, the proposed heterostructure (HZOHetero) exhibits a ≈25% reduction in coercive voltage and an approximately 10% increase in capacitance compared to conventional ferroelectric HZO capacitors, while maintaining the same physical thickness. These improvements originate from polarization switching in the MPB layer near 0 V, which synergistically enhances the effective electric field across the ferroelectric layer, together with an optimized phase balance that lowers the polarization switching barrier. This MPB-based heterostructure strategy offers a CMOS-compatible and energy-efficient pathway for advanced ferroelectric capacitors targeting low-power memory applications.