综述了氮化铝面内伸缩模态的射频MEMS谐振器。氮化铝面内伸缩模态谐振器(contour-mode resonator,CMR)利用了氮化铝薄膜的压电效应,由器件的机械谐振再通过机电转化实现谐振功能,基本结构为电极层-氮化铝层-电极层。当前研究的两种典型的器件结构为方形振子梳齿电极结构和圆盘振子电容式结构。概述了氮化铝CMR的制备工艺,并重点介绍了磁控溅射法生长薄膜和ICP刻蚀等主要工艺环节。分别对氮化铝CMR的谐振频率、品质因子、温度稳定性和动态电阻等主要性能参数进行了理论分析,针对谐振器各参数的提升给出了具体的改进方向,同时讨论了某些性能的提升所带来的负面影响。氮化铝CMR具备面内集成的优点,随着器件频率的提高,将在无线通信领域具有广阔的应用前景。
The AlN contour-mode RF MEMS resonators are reviewed. The piezoelectric effect of the AlN thin film is used in the contour-mode resonator (CMR). The resonant function is achieved by the mechanical resonance and electromechanical conversion. The basic structure is electrode layer-AlN layer-electrode layer. Two typical structures of the current contour-mode resonators are introduced, i.e. the square oscillator with the comb electrode structure and the disc oscillator with the capacitive structure. Then the fabrication process of the CMR is presented, with the emphasis on some major steps, such as magnetron sputtering for the growth of the thin film and ICP etching. The theoretical analysis for the major parameters of the CMR, such as the resonant frequency, quality factor, temperature stability and motional resistance are made respectively. The specific improvement directions of the parameters for the CMR are given. Meanwhile, some negative impacts of the improvement for some parameters are discussed. Owing to the advantage of the integration, with the enhancement of the frequency, the AlN CMR has wide application prospects in the field of wireless communications.