Simultaneously inducing preferred crystalline orientation with a strong piezoelectric response in polycrystalline aluminum nitride (AlN) thin films by atomic layer deposition is a technical challenge due to the upscaling of the integration of piezoelectric functionalities, such as sensing and actuation, in micro-devices without any poling process. Utilizing low-temperature plasma-enhanced atomic layer deposition (PE-ALD), highly c-axis-oriented AlN films have been prepared with precise control over the relative composition, purity levels, and chemical states of constituent elements. Tailoring thermodynamic parameters, such as the growth temperature and purging time after the trimethylaluminum precursor pulsing before the N2:H2:Ar plasma reaction, provide the possibility of modulating the texture coefficient and the relative piezoelectric response. The effective transverse piezoelectric e31,f coefficient of 0.37 C/m2 was achieved on the AlN film grown at 250 °C and 30 s with the highest texture coefficient TC(002) of 2.75 along the c-axis orientation. The process proposed, at a low temperature with the highly conformal growth of aluminum nitride thin films by PE-ALD, opens up pathways to design novel piezoelectric functional materials for micro-electro-mechanic system devices with complementary metal oxide semiconductor process temperature compatibility.

中文翻译：

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通过等离子体增强原子层沉积在低温下生长的 AlN 薄膜的薄膜纹理驱动压电

通过原子层沉积在多晶氮化铝 (AlN) 薄膜中同时诱导具有强压电响应的优选晶体取向是一项技术挑战，这是由于压电功能的集成升级，例如传感和驱动，在没有任何微器件的情况下极化过程。利用低温等离子体增强原子层沉积 (PE-ALD)，通过精确控制组成元素的相对成分、纯度水平和化学状态，制备了高度 c 轴取向的 AlN 薄膜。在 N2:H2:Ar 等离子体反应之前调整三甲基铝前驱体脉冲后的生长温度和吹扫时间等热力学参数，为调节织构系数和相对压电响应提供了可能性。在 250 °C 和 30 s 生长的 AlN 薄膜上实现了 0.37 C/m2 的有效横向压电 e31,f 系数，沿 c 轴方向的最高织构系数 TC(002) 为 2.75。该工艺在低温下通过 PE-ALD 高度共形生长氮化铝薄膜，开辟了为具有互补金属氧化物半导体工艺温度兼容性的微机电系统器件设计新型压电功能材料的途径。