Abstract The ferroelectric characteristics of undoped hafnium oxide (HfO2) in titanium nitride (TiN)/HfO2/TiN stacks exhibited improved remanent polarization by controlling the nitrogen gas flow during TiN deposition in this work. Electrical measurements revealed that samples with a higher N2/(Ar + N2) ratio obtained a higher remanent polarization of approximately 10 μC/cm2 at 2.5 V but exhibited a larger leakage current and less reliability. Among all the samples, the sample with a N2/(Ar + N2) ratio of 33% exhibited a relatively high remanent polarization of 12 μC/cm2 and excellent endurance over 108 cycles. Through X-ray photoelectron spectroscopy (XPS) analysis, it was observed that increasing the N2 gas flow during TiN electrode deposition contributed to excessive N-diffusion, leading to the creation of more oxygen vacancies and subsequently to device failure. Therefore, controlling the appropriate N2 gas flow during TiN deposition is crucial to enhance the ferroelectric characteristics of undoped HfO2. The results of this study may be applicable to future work on nonvolatile memory applications.

中文翻译：

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未掺杂二氧化铪薄膜铁电性与氮掺入的相关性

摘要 在这项工作中，氮化钛 (TiN)/HfO2/TiN 叠层中未掺杂的氧化铪 (HfO2) 的铁电特性通过控制 TiN 沉积过程中的氮气流量表现出改善的剩余极化。电气测量表明，具有较高 N2/(Ar + N2) 比率的样品在 2.5 V 下获得了大约 10 μC/cm2 的较高剩余极化，但表现出较大的漏电流和较低的可靠性。在所有样品中，N2/(Ar + N2) 比为 33% 的样品表现出相对较高的 12 μC/cm2 剩余极化和超过 108 次循环的优异耐久性。通过 X 射线光电子能谱 (XPS) 分析，观察到在 TiN 电极沉积过程中增加 N2 气流有助于过度 N-扩散，导致产生更多的氧空位并随后导致器件故障。因此，在 TiN 沉积过程中控制适当的 N2 气流对于增强未掺杂 HfO2 的铁电特性至关重要。这项研究的结果可能适用于非易失性存储器应用的未来工作。