Interfacial stress present in ferroelectric thin films is known to affect largely their piezoelectric properties by modifying crystal orientation and domain structure. Here, a nonconventional way is proposed to substantially improve the polarization and piezoelectric characteristics of Pb(Zr,Ti)O₃ thin films by modifying the surface of the typical Si substrate into an embossed structure with Ni nanodots. Uniform Ni nanodot arrays are successfully produced by an external magnetic field through the consolidation process of thin Ni layer. The exceptionally large thermal expansion mismatch of ≈94% between the thin films and the Ni nanodots is believed to induce a large local‐compressive stress around the nanodot region and thus the intensified orientation toward c‐axis. For this demonstration, the in situ sputtering processing enabled by combining heavily 12 mol% Nb‐doping with a bottom electrode structure of Ir/TiW is used. As a highlight of the improvement, a significant increase of ≈33% in effective piezoelectric coefficient is observed for the 90 nm Ni nanodot case. An apparent shift of the polarization–electric field curve suggests the existence of internal field, as an evidence of the in situ domain formation.

中文翻译：

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Ni纳米点阵列上大局部压缩应力诱导的锆钛酸铅钛薄膜压电特性的改善

已知存在于铁电薄膜中的界面应力通过改变晶体取向和畴结构而在很大程度上影响其压电性能。在此，提出了一种非常规的方法，通过将典型的Si衬底的表面改性为具有Ni纳米点的压花结构，从而实质上改善了Pb（Zr，Ti）O ₃薄膜的极化和压电特性。均匀的Ni纳米点阵列是通过外部磁场通过薄Ni层的固结过程成功产生的。薄膜和Ni纳米点之间的≈94％的异常大的热膨胀失配被认为会在纳米点区域周围引起很大的局部压缩应力，并因此导致朝向c的取向增强。-轴。在本演示中，使用了通过结合大量12 mol％的Nb掺杂和Ir / TiW的底部电极结构实现的原位溅射工艺。作为改进的亮点，对于90 nm Ni纳米点，有效压电系数显着增加了≈33％。极化-电场曲线的明显偏移表明存在内部场，这是原位域形成的证据。