AI 中文总结
本研究构建Ce掺杂HfO2的温度-掺杂相图，发现掺杂提升高对称相稳定性与 endurance但降低极化，为优化超薄铁电HfO2器件提供了成分与可靠性调控框架。
AI 中文摘要
研究了超薄外延Hf1-xCexO2（CHO）薄膜的结构与铁电性能，其Ce掺杂浓度范围为5%≤x≤20%，并分析了温度对性能的影响。针对10 nm厚薄膜构建了温度-掺杂相图，结果显示：随着Ce含量增加，材料从铁电正交相系统演化至四方相和立方相；当x=5%时，正交-四方相变温度约为800℃，x=15%时降至约300℃，表明掺杂可显著稳定高对称相；剩余极化强度随x从5%增至20%，从约15 μC/cm²降至3.8 μC/cm²；与之相反， endurance显著提升，高Ce浓度样品的循环稳定性大幅增强，可承受高达10⁸次循环。极化与 endurance的相反趋势与正交相畸变减小相关，说明Ce掺杂HfO2的疲劳缓解与结构演化有关。这些结果为优化超薄铁电HfO2器件的成分与可靠性提供了框架。
英文摘要
The structural and ferroelectric properties of epitaxial Hf1-xCexO2 (CHO) thin films in the ultrathin regime are investigated as a function of Ce concentration (5% <= x <= 20%) and temperature. A temperature-doping phase diagram is established for 10 nm films, showing a systematic evolution from the ferroelectric orthorhombic phase to tetragonal and cubic phases with increasing Ce content. The orthorhombic-tetragonal transition temperature decreases from ~800°C at x = 5% to $~300°C$ at x = 15%, indicating strong stabilization of higher-symmetry phases with doping. Consistently, the remanent polarization decreases from ~15 to $3.8 μC/cm2$ as x increases from 5% to 20%. In contrast, the endurance improves significantly, with higher Ce concentrations exhibiting markedly enhanced cycling stability up to 108 cycles. The opposing trends of polarization and endurance are correlated with reduced orthorhombic distortion, suggesting that fatigue mitigation in Ce-doped HfO2 is linked to structural evolution. These results provide a framework for optimizing composition and reliability in ultrathin ferroelectric HfO2 devices.
