As a high-k material, hafnium oxide (HfO₂) has been used in gate dielectrics for decades. Since the discovery of polar phase in Si-doped HfO₂ films, chemical doping has been widely demonstrated as an effective approach to stabilize the ferroelectric phase in HfO₂ based thin films. However, the extra capping layer deposition, post-growth annealing and wake-up effect are usually required to arouse the ferroelectricity in HfO₂ based thin films, resulting in the increase of complexity for sample synthesis and the impediment of device application. In this study, the ferroelectricity is observed in non-capped dopant-free HfO₂ thin films prepared by pulsed laser deposition (PLD) without post-growth annealing. By adjusting the deposited temperature, oxygen pressure and thickness, the maximum polarization up to 14.7 μC/cm² was obtained in 7.4 nm-thick film. The fraction of orthorhombic phase, concentrations of defects and size effects are considered as possible mechanisms for the influences of ferroelectric properties. This study indicates that PLD is an effective technique to fabricate high-quality ferroelectric HfO₂ thin films in the absence of chemical doping, capping layer deposition and post-growth annealing, which may boost the process of nonvolatile memory device application.

作为一种高 k 材料，氧化铪 (HfO ₂ ) 已在栅极电介质中使用了数十年。自从在Si掺杂的HfO _{2薄膜中发现极性相以来，化学掺杂已被广泛证明是稳定HfO 2}基薄膜中铁电相的有效方法。然而，通常需要额外的覆盖层沉积、生长后退火和唤醒效应来激发HfO ₂基薄膜的铁电性，从而增加了样品合成的复杂性，阻碍了器件的应用。在这项研究中，在非封端的无掺杂 HfO _{2中观察到铁电性}通过脉冲激光沉积 (PLD) 制备的薄膜无需生长后退火。通过调整沉积温度、氧气压力和厚度，在 7.4 nm 厚的薄膜中获得了高达 14.7 μC/cm ^{2的最大极化。}斜方晶相的比例、缺陷浓度和尺寸效应被认为是影响铁电性能的可能机制。该研究表明，PLD是一种在没有化学掺杂、覆盖层沉积和生长后退火的情况下制造高质量铁电HfO ₂薄膜的有效技术，这可能会促进非易失性存储器件应用的进程。