Sc-doped AlN with the wurtzite structure has excellent performance as a piezoelectric material. The phase stability of the (Al, Sc)N wurtzite phase is very important in designing highly functional piezoelectric materials. In this work, we assessed the thermodynamic parameters of the Al–Sc–N ternary system by incorporating the results of first-principles calculations into the calculation of phase diagrams (CALPHAD) method. The calculated Sc–N binary and Al–Sc–N ternary phase diagrams were consistent with the reported experimental results, where the (Al, Sc)N wurtzite phase exhibited phase separation. Because Sc-doped AlN is normally deposited on a substrate, we also evaluated the stability of the (Al, Sc)N wurtzite phase by considering the strain energy generated between the substrate and the thin film. It was found that the tendency to phase separation can be suppressed by decreasing the thickness of the thin film, which is qualitatively consistent with experimental reports.

具有纤锌矿结构的掺Sc的AlN作为压电材料具有出色的性能。（Al，Sc）N纤锌矿相的相稳定性在设计高功能压电材料中非常重要。在这项工作中，我们通过将第一性原理计算的结果合并到相图的计算（CALPHAD）方法中，评估了Al–Sc–N三元系统的热力学参数。计算的Sc–N二元相和Al–Sc–N三元相图与已报道的实验结果一致，其中（Al，Sc）N纤锌矿相表现出相分离。由于掺Sc的AlN通常沉积在衬底上，因​​此，我们还考虑了衬底和薄膜之间产生的应变能，评估了（Al，Sc）N纤锌矿相的稳定性。