Revealing the Role of Spacer Layer in Domain Dynamics of Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> Thin Films for Ferroelectrics
Ren‐Ci Peng, Shubin Wen, Xiaoxing Cheng, Long‐Qing Chen, Min Liao, Yichun Zhou
Abstract
Abstract HfO 2 ‐based ferroelectrics offer promises for next‐generation nonvolatile nanoscale devices owing to excellent CMOS compatibility and robust ferroelectricity at the nanoscale. However, fundamentally understanding the mechanism of polarization reversal and domain dynamics is challenging because the role of the spacer layer at the domain level in HfO 2 ‐based ferroelectrics remains elusive. Here, it is realized that visualization of time‐resolved dynamics of nanoscale domain configurations in the epitaxial Hf 0.5 Zr 0.5 O 2 thin films using phase‐field simulations. Scale‐free domain independent switchability (namely, irreducible stable polar domain down to 1 nm lateral size) and sharp domain walls that originate from weak interactions between adjacent domains characterized by the reduced gradient energy coefficient, which unravels the mesoscale mechanism of spacer layer in domain dynamics are demonstrated. Meanwhile, it is revealed that 180° polarization switching is dominated by the nucleation of a new domain with a high nucleation density, well described by the nucleation‐limited switching model. This study not only provides a fundamental mesoscale mechanism of the spacer layer, but also stimulates further studies on the manipulation of ultra‐scaled single domain state for designing high‐density and fast‐speed HfO 2 ‐based ferroelectric memory.