Hafnium oxide acts as a functional dielectric in a variety of traditional and emerging nonvolatile memory technologies. To investigate the effect of heavy ion irradiation on its crystalline structure, highly textured hafnium oxide films were irradiated with 1.635 GeV Au ions of fluences ranging from $1\times 10^{9}$ to $7\times 10^{12}$ ions/cm ² . For monoclinic hafnium oxide films, a fluence-dependent defect-induced phase transition to a defect-stabilized tetragonal phase is identified. In low-temperature tetragonal hafnium oxide films, the X-ray diffraction (XRD) patterns show an out-of-plane lattice constant decrease with increasing irradiation fluence. Observed crystalline changes are strikingly similar to trends found for oxygen-engineered hafnium oxide films, directly grown at varying oxidation conditions. The correlation of structural changes with in vacuo electron spectroscopy data of oxygen-engineered films suggests that the irradiation of hafnium oxide leads to an oxygen loss that increases with fluence. Therefore, the underlying mechanism of the monoclinic to tetragonal phase transition is obviously directly related to oxygen defects. This new information allows predictions of device stability under swift heavy ion irradiation of hafnium oxide-based devices.

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氧化铪薄膜中缺陷诱导的相变：比较重离子辐照和氧工程效应

氧化铪在各种传统和新兴的非易失性存储器技术中充当功能性电介质。为了研究重离子辐照对其晶体结构的影响，用 1.635 GeV Au 离子辐照高度织构的氧化铪薄膜，其通量范围为 $1\乘以 10^{9}$ 到 $7\乘以 10^{12}$ 离子/厘米 ² 。对于单斜氧化铪薄膜，确定了与缺陷相关的缺陷诱导相变到缺陷稳定的四方相。在低温四方氧化铪薄膜中，X 射线衍射 (XRD) 图案显示出面外晶格常数随着辐照通量的增加而降低。观察到的晶体变化与氧工程氧化铪薄膜的趋势惊人相似，在不同的氧化条件下直接生长。结构变化与氧工程薄膜的真空电子能谱数据表明，氧化铪的辐照会导致氧损失，随着通量的增加而增加。因此，单斜向四方相变的潜在机制显然与氧缺陷直接相关。这一新信息可以预测基于氧化铪的设备在快速重离子辐照下的设备稳定性。