片上集成MEMS射频滤波器

On-chip Integrated MEMS-based RF Filters

研究采用MEMS工艺技术制造可在硅集成电路片上集成的射频滤波器。MEMS工艺技术实现了高性能嵌入式螺管电感和金属-绝缘层-金属电容元件的集成制造。整个微加工制造工艺为低温工艺,可与CMOS集成电路工艺实现后端集成。基于此工艺,设计和实现了应用于5 GHz射频频段的微小化的片上集成滤波器,包括一种低通滤波器和一种带通滤波器。测试结果表明,5阶低通滤波器的-1.5 dB转折频率在5.3 GHz频率,从直流到5 GHz频率的插入损耗小于1.06 dB.实现的带通滤波器为两阶谐振耦合式,在中心频段5.3 GHz的最小插入损耗为4.3 dB,通带内的回波损耗大于13 dB.研究结果表明:该微加工技术适用于无源器件和滤波器电路的CMOS后端集成,适合高性能射频片上系统的应用。

This paper presented a post-CMOS compatible micromachining process for implementation of compact-sized on-chip integrated RF filters. The micromachining process achieves simultaneous formation of high performance concave solenoid inductors and metal-insulator-metal （MIM） capacitors. The fabrication process is in low temperature condition and suitable for post process of CMOS integrated circuits. Based on this process, compact-sized RF filters for 5 GHz band are designed and fabricated, including a lowpass type and a bandpass type. From the measured results, the 5th order lowpass filter has - 1.5 dB cut-off frequency at 5.3 GHz and shows insertion loss of less than 1.06 dB up to 5 GHz. The bandpass filter implemented is a 2nd order coupled-resonator type. The measured minim um insertion toss is 4. 3 dB at passband around 5.3 GHz, and the return loss is better than 13 dB in the designed passband. The results show that the developed micromachining technology is suitable for post-CMOS integration of RF passive devices and filter circuits. This technology is promising for implementation of radio-frequency system-on-a-chip （ RF- SoC）.