一种用于RF MEMS移相器及开关可变电容的复合微桥膜结构

提出了一种基于微机械工艺的新型复合微桥膜结构 ,由低应力SiN/SiO2 (0 .5 μm/5 0nm )及Cr/Au(30nm/1μm)构成。相应的工艺流程较为简单。对影响其特性的因素进行了理论分析 ,并提出了 3种桥膜的平面结构 ;利用静电 /力耦合有限元法分析了各种结构的静电驱动特性以及各阶模态 ,结果得到了令人满意的驱动和机械性能 ;通过有限元高频仿真软件对桥膜结构与共面波导形成的可调电容结构进行了分析 ,结果表明其具有良好的射频 /微波性能。该桥膜结构适用于RFMEMS开关、移相器及开关式可调电容和滤波器等

A novel composite membrane bridge structure for RF MEMS phase shifter and switched tunable capacitor

This paper presents a novel micromachined metal/dielectric composite membrane bridge structure, which consists of a Cr/Au layer of 30nm/1μm on a low stressed PECVD SiN/SiO 2 (0.5μm/50nm) layer. The low residual stress SiN is incorporated due to its excellent dielectric and mechanical perfor mance. The fabrication process is rather simple. Factors that affect its properties are analyzed theoretically at first. The bridge structure is more reliable. Three membrane bridge structures with different planar geometry are designed. Mechanical/electrostatic and high frequency finite element analysis tools are used to explore their characteristics. It can be seen from the results that satisfying actuating behavior is obtained through elaborate optimization of the bridge structure and shape. Combined with coplanar waveguide, the bridge structures exhibit good microwave/millimeter wave performance. These features make the micro bridge structure an optimal solution for RF MEMS phase shifters, switched tunable filters, capacitors and switches.