Reliability Improvement from La₂O₃ Interfaces in Hf_0.5Zr_0.5O₂‐Based Ferroelectric Capacitors

Abstract

Further optimization of a typically reported ferroelectric capacitor comprised of a Hf0.5Zr0.5O2 ferroelectric thin film with TiN electrodes is explored by introducing an additional non‐ferroelectric La2O3 interfacial layer evaluated at different positions in the capacitor stack. The role of the interface to the ferroelectric layer is investigated and discussed, with the main focus directed toward the reliability of the device for non‐volatile memory applications. With this investigation, different degradation mechanisms determining electric field cycling and polarization retention are observed, and it is concluded that modifying the bottom interface between the electrode and the ferroelectric layer has the best potential to provide a benefit in device performance.

Enhanced Ferroelectricity in Hf‐Based Ferroelectric Device with ZrO2 Regulating Layer

“…[11] However, its low remnant polarization intensity and high annealing temperature have restricted its further development. [12] In order to improve the remanent polarization intensity of Hf-based ferroelectric materials, researchers generally insert an interface layer between the electrode and the ferroelectric layer, such as TiO 2 , [13,14] Al 2 O 3 , [15,16,17] HfO 2 , [18] ZrO 2 , [19,20] La 2 O 3 , [21] CeO x , [22] etc. Among them, there are reported works on the performance improvement of ZrO 2 layer in memory [23][24][25] and ZrO 2 has good lattice matching effect with HfO 2 , which was suitable as insert layer for improving performances of Hf-based devices.…”

Enhanced Endurance and Imprint Properties in Hf0.5Zr0.5O2−δ Ferroelectric Capacitors by Tailoring the Oxygen Vacancy

“…Figure shows the benchmarks of the reliability of the HZO capacitor in our work compared with other published HfO 2 -based capacitors. ,− By decreasing the oxygen vacancy concentration to 1.9%, an endurance of over 10 11 cycles and an imprint with less than 0.6 MV/cm coercive field shift after 2 h of baking at 120 °C were achieved simultaneously, which provides a strategy to fabricate a highly reliable ferroelectric memory device.…”

The Electrode‐Ferroelectric Interface as the Primary Constraint on Endurance and Retention in HZO‐Based Ferroelectric Capacitors

“…[25] To better understand field cycling degradation and imprint shift, impedance spectroscopy was implemented in this work during reliability measurements. Impedance was measured after a given number of field cycles or time intervals, and the results were fitted to a two resistor/capacitor (RC)-element analysis model (as shown in Figure 2 and described elsewhere [26,27] ). Starting from pristine interface and bulk resistance values of about 1 kΩ and 500 MΩ, respectively, it was possible to determine a decrease in the interface resistance of roughly 30% and 10% for retention and electric field cycling measurements, respectively.…”