The impact of the high-power impulse magnetron sputtering (HiPIMS) pulse width on the crystallization, microstructure, and ferroelectric properties of undoped HfO2 films is investigated. HfO2 films were sputtered from a hafnium metal target in an Ar/O2 atmosphere, varying the instantaneous power density by changing the HiPIMS pulse width with fixed time-averaged power and pulse frequency. The pulse width is shown to affect the ion-to-neutral ratio in the depositing species with the shortest pulse durations leading to the highest ion fraction. In situ x-ray diffraction measurements during crystallization demonstrate that the HiPIMS pulse width impacts nucleation and phase formation, with an intermediate pulse width of 110 μs stabilizing the ferroelectric phase over the widest temperature range. Although the pulse width impacts the grain size with the lowest pulse width resulting in the largest grain size, the grain size does not strongly correlate with the phase content or ferroelectric behavior in these films. These results suggest that precise control over the energetics of the depositing species may be beneficial for forming the ferroelectric phase in this material.

中文翻译：

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高功率脉冲磁控溅射脉宽对氧化铪薄膜成核、结晶、微结构和铁电性能的影响

研究了高功率脉冲磁控溅射 (HiPIMS) 脉冲宽度对未掺杂 HfO2 薄膜的结晶、微观结构和铁电性能的影响。HfO2 薄膜是在 Ar/O2 气氛中从铪金属靶溅射而成，通过改变具有固定时间平均功率和脉冲频率的 HiPIMS 脉冲宽度来改变瞬时功率密度。结果表明，脉冲宽度会影响沉积物质中的离子与中性比，最短的脉冲持续时间会导致最高的离子分数。结晶过程中的原位 X 射线衍射测量表明，HiPIMS 脉冲宽度影响成核和相形成，110 μs 的中间脉冲宽度可在最宽的温度范围内稳定铁电相。尽管脉冲宽度影响晶粒尺寸，最低脉冲宽度导致最大晶粒尺寸，但晶粒尺寸与这些薄膜中的相含量或铁电行为没有很强的相关性。这些结果表明，精确控制沉积物质的能量可能有利于在该材料中形成铁电相。