engleski

Silicon Carbide Tunable MEMS Resonator with Wide Operation Range

Electrically tunable filters with a wide operational range are crucial elements in both multi- band communication systems and wideband tracking receivers because they have the ability to replace filter banks (Mansour et al. ; 2014). Micro-electro- mechanical system (MEMS) resonators have emerged as a potential candidate technology for im- plementation of high-Q tunable filters that are able to solve power consumption and miniaturization issues (Van Beek et al., 2012). One of the most promising materials for high efficiency MEMS resonators is silicon carbide because of its excellent electrical, mechanical and chemical properties (Sarro ; 2000). Integration of MEMS resonators with electronic cir- cuits requires the ability for electrical actuation and and sensing of the mechanical vibration. Electro- thermal actuation technique has been attracting in- creasing attention as a means of allowing simple fab- rication process, low actuation voltages, impedance matching and effective frequency tuning. Recently, we have demonstrated a silicon carbide MEMS reso- nant device with electrothermal actuation and piezo- electric sensing (Sviličić et al. ; 2012). For the elec- trical sensing, piezoelectric transduction has been used because it enables stronger electromechanical coupling and relatively simpler fabrication process compared to the alternative electrostatic transduction. In this paper, we present a two-port 3C- SiC MEMS resonator actuated with u- shaped designed electro- thermal actuator (input port) in order to provide tun- able filter function with wide operation range (Figure 1). The electrothermal actuator is formed of thin plat- inum (Pt) layer, while piezoelectric sensor (output port) is formed of lead-zirconium- titanate layer sandwiched between two Pt layers. Two-port trans- mission frequency response measurements per- formed in atmospheric conditions have shown that the resonator's operating frequency can be adjusted up to 33% of the un-tuned resonant frequency by applying DC bias voltage in the range 1 V – 7 V (Figure 2). Details of the design, fabrication process- es and measurement setup will be presented. The electrothermal actuation technique will be studied with an emphasis on the influence of DC tuning volt- age on the resonant frequency, Q factor and motional resistance.

MEMS resonator; tunable filter; electro- thermal actuation; piezoelectric sensing

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