Scandium-alloyed aluminum nitride (AlScN) is a potential material for micro-electromechanical systems because of its unique advantages, such as strong piezoelectric effect and high thermal stability. However, issues related to its stability and interaction with other materials in multilayer systems require investigation. The formation of new phases at the interface between piezomaterial and electrode material can lead to the device failure. In this study, multilayer structures Si substrate/AlN/Ti-Mo/Al _0.8 Sc _0.2 N/top electrode (TE) were studied after annealing at a wide range of temperatures and durations. Four different TE materials (i.e. Al, AlSi (1%), Mo/Al, and Mo) were examined to determine the most reliable electrode material for the structure. The phase stability, interfacial quality, and piezoelectric response of the multilayer systems after thermal annealing were investigated. The structure with Mo TE layer was stable after annealing at 800 °C for 300 h and at 1000 °C for 100 h. None of the structures formed any new phases at the interface between the electrode layer and AlScN. The transverse piezoelectric coefficient (e _31,f ) was determined for Al _0.8 Sc _0.2 N before and after annealing. The absolute value of the e _31,f was −1.39 C/m ² for as-deposited structure and −1.67 C/m ² for the same structure annealed for 300 h at 800 °C. [2020-0361]

中文翻译：

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压电微机械超声换能器（pMUT）制造的基于AlScN的多层系统的表征

dium合金氮化铝（AlScN）由于其独特的优势（如强压电效应和高热稳定性）而成为微机电系统的潜在材料。但是，与它的稳定性以及与多层系统中其他材料的相互作用有关的问题需要研究。在压电材料和电极材料之间的界面处形成新相会导致设备故障。在这项研究中，多层结构Si衬底/ AlN / Ti-Mo / Al _0.8 Sc _0.2 在宽范围的温度和持续时间下进行退火后，对N /顶部电极（TE）进行了研究。检查了四种不同的TE材料（即Al，AlSi（1％），Mo / Al和Mo）以确定该结构最可靠的电极材料。研究了热退火后多层体系的相稳定性，界面质量和压电响应。在800°C退火300 h和1000°C退火100 h后，带有Mo TE层的结构是稳定的。没有一种结构在电极层和AlScN之间的界面上形成任何新的相。 测定 退火前后Al _0.8 Sc _0.2 N的横向压电系数（e _31，f） 。e _31，f的绝对值 对于沉积态结构，其为-1.39 C / m ²，对于相同结构的-1.67 C / m ²在800°C下退火300 h。[2020-0361]