Ferroelectric aluminum scandium nitride (Al_0.7Sc_0.3N) has attracted increasing interest due to its high remanent polarization (P_r, >100 µC cm⁻²) and coercive field (E_c, >5 MV cm⁻¹). The four radio frequency reactive magnetron sputtering conditions (sputtering power, N₂ flow ratio, pressure, and temperature) influence the ferroelectric and material properties of 45 nm-thick Al_0.7Sc_0.3N deposited on the TiN/SiO₂/Si substrate. Crystallinity is enhanced under the deposition conditions with higher adatom energy but deteriorates when the growth condition increases over the optimum. The well-crystallized films have (002)-preferred orientation with the in-plane compressive stress imposed by the peening effect and thermal stress. The imposed compressive stress increases the c₀/a₀ value, where c₀ and a₀ mean the c- and a–axis lattice parameters, which eventually increases the E_c of the film. P_r increases with the c₀/a₀ value, but other factors also influence the change. The films with high oxygen concentration show the wake-up properties due to the large percentage of domain walls and their depinning. Finally, ferroelectricity is confirmed with films down to a thickness of 20 nm. However, the thinnest film shows a higher E_c and lower P_r. These findings imply the presence of non-ferroelectric interfacial layers, which induce the depolarization effect.

中文翻译：

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20 nm以下Al0.7Sc0.3N薄膜射频反应磁控溅射最佳沉积条件研究

铁电铝钪氮化物 (Al _0.7 Sc _0.3 N) 由于其高剩余极化 ( P _r , >100 µC cm ^-2 ) 和矫顽场 ( E _c , >5 MV cm ^-1 ) 引起了越来越多的关注。四种射频反应磁控溅射条件（溅射功率、N ₂流量比、压力和温度）影响沉积在 TiN/SiO _{2上的 45 nm 厚 Al 0.7} Sc _{0.3 N 的铁电体和材料特性}/Si衬底。在具有较高吸附原子能量的沉积条件下结晶度提高，但当生长条件增加超过最佳值时结晶度恶化。结晶良好的薄膜具有 (002) 优先取向，具有由喷丸效应和热应力施加的面内压应力。施加的压应力增加了c ₀ / a ₀值，其中c ₀和a ₀表示c - 和a -轴晶格参数，最终增加了薄膜的E _c。P _r随c ₀ / a增加₀值，但其他因素也会影响变化。由于大比例的畴壁及其脱钉，具有高氧浓度的薄膜显示出唤醒特性。最后，铁电性通过厚度为 20 nm 的薄膜得到证实。然而，最薄的薄膜表现出更高的E _c和更低的P _r。这些发现暗示了非铁电界面层的存在，这会引起去极化效应。