HfO₂-ZrO₂ Superlattice Ferroelectric Capacitor With Improved Endurance Performance and Higher Fatigue Recovery Capability

Abstract

HfO₂-ZrO₂ superlattice (SL) ferroelectric (FE) capacitor is demonstrated to have improved endurance performance and higher fatigue recovery capability compared to the HfZrO_<i>x</i> (HZO) device. During the cycling of polarization (<inline-formula> <tex-math notation="LaTeX">${P}$ </tex-math></inline-formula>) <i>vs.</i> voltage (<inline-formula> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula>) loops, the SL metal-FE-metal (MFM) capacitor exhibits the higher <inline-formula> <tex-math notation="LaTeX">${P}$ </tex-math></inline-formula> and the lower leakage current over the HZO device indicating the lower defect density in SL. The SL capacitor achieves an endurance of <inline-formula> <tex-math notation="LaTeX">${5}\times {10} ^{{12}}$ </tex-math></inline-formula> cycles, which is three orders of magnitude higher than the HZO device. The <inline-formula> <tex-math notation="LaTeX">${P}$ </tex-math></inline-formula> fatigue of the SL capacitor can be fully recovered through a &#x007E;30 s break, and that of HZO is only partially recovered utilizing the higher field cycling. This is because the trapping/detrapping process significantly decreases in HfO₂-ZrO₂ SL over HZO capacitor by the reduced defect density. These results prove that the HfO₂-ZrO₂ SL is a promising technology for endurance unlimited FE random access memory.