The ferroelectric properties of ultrathin Y-doped HfO2 films were investigated. Ferroelectricity was demonstrated experimentally in 3 nm-thick Y-doped HfO2 via direct detection of displacement currents during polarization switching. The dependence on the HfO2 thickness within the 30 to 3 nm range revealed that the ferroelectric properties decrease rapidly below a critical thickness. In the ultrathin HfO2 region, methods such as higher Y doping or metal capping annealing were required to further stabilize the ferroelectric phase. These methods could be used to enhance the switchable polarization (Psw) to 35 μC/cm2 in 5 nm- and 10 μC/cm2 in 3 nm-thick Y-doped HfO2. This paper indicates that HfO2 ferroelectricity is scalable even in the ultrathin region.

中文翻译：

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在低至 3 nm 的超薄区域中铁电 HfO2 的演变

研究了超薄 Y 掺杂 HfO2 薄膜的铁电性能。通过在极化切换期间直接检测位移电流，在 3 nm 厚的 Y 掺杂 HfO2 中实验证明了铁电性。在 30 到 3 nm 范围内对 HfO2 厚度的依赖性表明，铁电性能在临界厚度以下迅速下降。在超薄 HfO2 区域，需要使用更高的 Y 掺杂或金属覆盖退火等方法来进一步稳定铁电相。这些方法可用于将可切换偏振 (Psw) 提高到 5 nm 中的 35 μC/cm2 和 3 nm 厚 Y 掺杂 HfO2 中的 10 μC/cm2。本文表明，即使在超薄区域，HfO2 铁电性也是可扩展的。