Atomic Origins of Leakage Paths in Epitaxial Al1–xScxN Thin Films

作者：Dirui Wu, Chao Li, Chao Li, Yabei Wu, Yanghe Wang, Jinxin Ge, Yihan Lei, Wenqing Zhang, Changjian Li, Changjian Li · 发表于：Nano Letters · 年份：2025 · DOI：10.1021/acs.nanolett.5c03675 · 被引用次数：5 · 研究领域：Metal and Thin Film Mechanics、GaN-based semiconductor devices and materials、Semiconductor materials and devices

Al 1– x Sc x N, a CMOS-compatible ferroelectric material with high residual polarization and Curie temperature, possesses excellent promise for high-temperature nanoelectronics. However, its high coercive field and leakage current lead to poor endurance, hindering device applications. Sc concentration is crucial to tune ferroelectric coercive field, but the link between Sc doping and leakage current is rarely explored. Here, we report Sc-rich metallic rocksalt nanoscale precipitates in epitaxial wurtzite Al 0.9 Sc 0.1 N via atomic resolution microstructural analysis and nanoscale bandgap mapping. These nanoscale precipitates reduce the local bandgap by 1.0 eV, creating percolation paths that elevate leakage current by 3 orders of magnitude─validated by I – V characterization and first-principles calculations. This result is surprising, as the overall Sc concentration (0.1) is far below the thermodynamic wurtzite-rocksalt phase boundary, highlighting that the Sc spatial distribution control is critical to suppress leakage current. Our approach is generic to study the microscopic origins of the leakage current in wurtzite-ferroelectric materials.