Search

In this paper we present the novel approach to design of a resonating sensor fabricated as a micro-electromechanical system (MEMS) made of the silicon nitride double clamped beam (microbridge) and the thin film metal paths enabling both actuation and read-out. We propose the on-chip implemented Wheatstone bridge circuit as a mean for increasing the actuation efficiency and readout sensitivity. Two of the bridge branches are actuating and sensing Lorentz loops while other two are reference resistors on immobile, supported structure. Such approach allowed to increase the response fourfold compared to single Lorentz loop. It was possible to observe the resonance in vacuum and in ambient conditions. The necessary power dissipation to actuate measurable vibrations were 130 pW and 13 nW, respectively.

Micromechanical cantilevers are attractive devices for force measurements. We report the results obtained for SMMM (Soft MetMolMEMS) silicon cantilever fabricated on silicon on insulator (SOI) substrate with piezoresistive deflection readout with the stiffness much lower than the typical piezoresistive silicon cantilever. The cantilever mechanical properties were characterised with laser vibrometer using the thermal noise technique (resonant frequency f res = 5474.2 Hz, quality factor Q = 19.4 and stiffness k = 0.042 Nm − 1 ). The piezoresistive detection sensitivity was evaluated by measuring externally induced mechanical vibrations optically with laser vibrometer and electrically using current-to-voltage converter and lock-in amplifier simultaneously. We obtained deflection sensitivity DS = 11 Vm − 1 and force sensitivity FS = 263 VN − 1 assuming typical bias voltage of 2 V. Such silicon cantilever may be successfully used in AFM investigation of fragile structures.

In this paper we present a method of fabrication and characterization of strain sensors fabricated with a focused electron beam induced deposition (FEBID) technology from Pt precursor. The FEBID structures were used as deflections sensors and applied to read-out resonance frequency of micromechanical bridges. In our experiments we have investigated silicon nitride structures with an integrated metallization path on which the FEBID strain sensors were deposited. In order to modify mechanical properties of the microbridge we developed and applied a focused ion beam (FIB) milling technology which allowed to modify the distribution of mechanical stress and consequently increase the deflection detection sensitivity. An atomic force microscopy (AFM) technology was applied to both characterize the electrical properties of the deposited structures and characterize properties of the fabricated devices. In this way the gauge factor (GF) of the FEBID fabricated nanogranular resistors (NGRs) of 4.25 was determined for the static microbridge deflection. Display Omitted The piezoresistive stress sensor on the silicon nitride microresonators were fabricated.The piezoresistive stress sensor were fabricated with focused electron beam induced deposition (FEBID) technology.We report a characterization procedures of microstructures using atomic force microscopy methods.