Gu Youdi, Shi Shu, Su Hanxin, Huangfu Geng, Jia Lanxin, Li Siqin, Sun Kaixuan, Wu Yichen, Zeng Tao, Teo Siewlang, Lin Ming, Zhu Yao, Wang Han, Chen Jingsheng
Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore.
Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis #08-03, Singapore, 138634, Singapore.
Small. 2025 Aug;21(34):e2502865. doi: 10.1002/smll.202502865. Epub 2025 Jul 1.
Wurtzite ferroelectric aluminum scandium nitrides (Al ScN) are highly appealing for their large remanent polarization, steep hysteresis, and easy integration with multiple mainstream semiconductor platforms. However, their applications are constrained by the inherently high coercive field (E), desperately needing comprehensive research of polarization switching for potentially lowering E. In particular, the correlations between polarization switching mechanisms and Sc doping levels remain underexplored. Here, the polarization switching kinetics in wurtzite ferroelectric Al ScN (x = 0.25-0.3) subjected to varied voltage amplitudes and pulse durations are investigated, revealing a mutable polarization switching. The AlScN sample displays uniform switching behavior described by the Kolmogorov-Avrami-Ishibashi (KAI) model, while the intermediate composition AlScN exhibits an ambiguous switching mechanism, more aligned with KAI model-based on mathematical fitting validation. Especially, AlScN with obviously reduced coercive and activation fields, exhibits a nucleation-limited-switching (NLS) mechanism. It is found that higher-level Sc doping generates more nucleation sites, reducing energy barriers and accelerating nucleation switching, driving the transition from KAI to NLS. Energetic analysis further elucidates the doping-induced crossover of switching mechanisms. These results provide new insight into the fundamental understanding of polarization switching in wurtzite ferroelectric nitrides, which is critical for realizing their optimal and reliable applications.
纤锌矿型铁电氮化铝钪（Al ScN）因其具有较大的剩余极化强度、陡峭的磁滞回线以及易于与多种主流半导体平台集成而备受关注。然而，它们的应用受到固有高矫顽场（E）的限制，迫切需要对极化切换进行全面研究以潜在地降低E。特别是，极化切换机制与Sc掺杂水平之间的相关性仍未得到充分探索。在此，研究了纤锌矿型铁电Al ScN（x = 0.25 - 0.3）在不同电压幅度和脉冲持续时间下的极化切换动力学，揭示了一种可变的极化切换。AlScN样品表现出由Kolmogorov - Avrami - Ishibashi（KAI）模型描述的均匀切换行为，而中间成分的AlScN表现出模糊的切换机制，基于数学拟合验证更符合KAI模型。特别是，具有明显降低的矫顽场和激活场的AlScN表现出成核限制切换（NLS）机制。研究发现，较高水平的Sc掺杂会产生更多的成核位点，降低能垒并加速成核切换，推动从KAI到NLS的转变。能量分析进一步阐明了掺杂诱导的切换机制交叉。这些结果为深入理解纤锌矿型铁电氮化物中的极化切换提供了新的视角，这对于实现其最佳和可靠应用至关重要。
