高Sc含量ScAlN薄膜的制备与表征

Preparation and characterization of ScAlN thin film with high scandium concentration

本文利用优化的种子层结构和工艺参数,以AlSc合金靶为靶源,以脉冲直流反应磁控溅射AlSc合金靶的方式在室温下制备了ScAlN薄膜,同时设计并制作了压电测试专用结构,解决了ScAlN腐蚀工艺不成熟的问题,结合X射线衍射仪、扫描电镜、能谱仪、准静态d33分析仪、纳米压痕法等方法表征了薄膜的结晶质量、组成成分和机电耦合系数等性能。由表征结果可知,所制备的Sc0.35Al0.65N薄膜具有高度c轴择优取向,摇摆曲线的半高宽低至2.167°,同时结晶致密,有少量贝壳状凸起。薄膜的压电常数d33为-23.4 pC/N,机电耦合系数k_(33)^(2)和k_(t)^(2)分别为34.6%和25.7%,具有制备FBAR等高性能压电MEMS器件的潜力。

In this study,a novel seed layer structure was used to prepare ScAlN piezoelectric thin films through pulsed DC reactive magnetron sputtering at room temperature with scandium aluminum alloy as the target source after optimizing the process parameters.A novel structure for d33 measurement was de⁃signed and fabricated to solve the problem that the wet etch process is still not mature.The crystal quality,components,and electromechanical coupling factor were measured using X-ray diffraction,scanning elec⁃tron microscopy,energy-dispersive X-ray spectroscopy,quasi-static d33 analysis,and nanoindentation.The Sc0.35Al0.65N film prepared was highly c-axis oriented,with a full width at half maximum of 2.167°.In addition,the film had a high crystal density with a few shell-like convex parts.The test results show that the piezoelectric constant d33 of the film is-23.4 pC/N,and the electromechanical coupling factors k_(33)^(2) and k_(t)^(2) are 34.6%and 25.7%,respectively.This result shows that the ScAlN film prepared in this study has great potential for the fabrication of high-performance microelectromechanical system piezoelectric de⁃vices,such as film bulk acoustic resonators.