Nitrogen vacancies (${\mathrm{V}}_{\mathrm{N}}$) are critical defects that influence the performance of wurtzite scandium-doped aluminum nitride ($\mathrm{A}{\mathrm{l}}_{1-x}\mathrm{S}{\mathrm{c}}_x\mathrm{N}$) ferroelectric devices. However, the microscopic mechanisms through which these vacancies influence leakage and breakdown behaviors remain insufficiently understood. Here, we investigate the formation energetics of ${\mathrm{V}}_{\mathrm{N}}$ in $\mathrm{A}{\mathrm{l}}_{1-x}\mathrm{S}{\mathrm{c}}_x\mathrm{N}$ using first-principles calculations guided by coordination-dependent defect stability principles and employing defect-tuned supercell models. Our results demonstrate that Sc-N bonds significantly lower the formation energies of ${\mathrm{V}}_{\mathrm{N}}$, with diminishing returns beyond two Sc coordination. Additionally, the spatial distribution of Sc plays a crucial role in the formation of conductive paths for ${\mathrm{V}}_{\mathrm{N}}$, suggesting that optimizing the Sc distribution can effectively suppress leakage current and delay breakdown. These insights advance the understanding of defect-driven challenges in $\mathrm{A}{\mathrm{l}}_{1-x}\mathrm{S}{\mathrm{c}}_x\mathrm{N}$ and open avenues for improving device reliability through defect engineering strategies.

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• Defects
• Ferroelectricity
• Nitrides
• Density functional theory
• First-principles calculations