Controlling the Ferroelectricity of Doped-HfO2 via Reversible Migration of Oxygen Vacancy

We have experimentally demonstrated that the ferroelectricity can be controlled by reversibly injecting oxygen vacancies ( ${V}_{\text {o}}{)}$ from the interfacial layer (IL) of TiOxNy to Hf $_{{0}.{5}}$ Zr0.5O2(HZO) or extracting them from HZO to IL in the titanium nitride (TiN) $/$ HZO $/$ TiN structure for the first time. The IL between the TiN electrode and HZO thin film plays a crucial role as the ${V}_{\text {o}}$ reservoir. By adjusting the electrical pre-stress time to modulate the ${V}_{\text {o}}$ concentration and distribution, HZO shows multiferroelectricity which can be switchable. In addition, the experimental multiferroelectricity can be correctly reproduced by the simulation with a phase-field polarization switching model. The simulated results herein strongly support the mechanism that modulating the ${V}_{\text {o}}$ migration reversibly from IL into HZO can achieve multiferroelectricity control.