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High-speed atomic force microscopy has thus far largely been limited to the use of small cantilevers in liquid, but the technique would greatly profit areas of nanotechnology that require the use of larger probes in air. We present polymer-based cantilevers with a low Q factor, an integrated electrothermal actuator and a sharp silicon tip. The devices can be used directly on commercial AFM setups utilizing a custom cantilever holder. They are suitable for high-speed tapping mode thanks to the high intrinsic damping of their polymer core. The integrated actuator allows for large amplitudes for off-resonance imaging, as well as for clean actuation tunes for tapping-mode imaging.

This paper presents a novel read-out approach both for eliminating parasitic feedthrough current and for enhancing the quality-factor (Q) of the resonating system at the same time. A new resonance characterization method based on sensing second harmonic component of the resonators was developed. Utilizing this method, the feedthrough current was eliminated and the signal-to-background ratio was increased from 0.9 dB to 35.5 dB. Furthermore, the Q of the resonating system was improved by 65% experimentally. It was shown that this method is suitable for eliminating both capacitive and resistive feedthrough current without using complex MEMS designs and interface electronics. (C) 2018 Elsevier B.V. All rights reserved.

This paper presents the investigation of two different capacitive feedthrough current elimination methods with an analysis of the effect of the capacitive feedthrough current on the resonance characteristics of electrostatically actuated and sensed resonant MEMS sensors. Electrostatically actuated and sensed resonators have various applications, such as accelerometers, gyroscopes, mass sensors, and temperature sensors. In most of these applications, as sensitivity increases, gain decreases. The capacitive feedthrough current between the drive and sense electrodes disturbs the resonance characteristics of the resonator, especially when the gain is rather small. In order to eliminate the dominating feedthrough current in such cases, two methods were proposed. In the first method, differential input signals were applied to two separate resonators, one active and one passive, sharing the same sense electrode. Although this method seems to be easily applicable to all types of resonators, this study has shown that mismatches between the resonator pair prevent perfect elimination of the feedthrough current. In the second method, a novel lateral electrostatic resonator with differential sense electrodes was designed and fabricated to eliminate the feedthrough current. Measurements showed that the feedthrough effect was successfully eliminated and 27 times higher SNRdB was achieved with this method. Moreover, it was successfully demonstrated that any mismatch can be compensated by a simple resistive adjustment. [2016-0288]

In this study, a fabrication method utilizing parylene bonding for gravimetric resonant based mass sensors is presented. First, parylene bonding was experimentally tested and compared with the literature. Average shear strength was measured as 16.3 MPa (sigma=3MPa). Then, resonators located on top of a microchannel for real-time detection were fabricated using the presented method. Simulations and experiments verify proper operation of the fabricated resonators, and the applicability of the method for fabricating similar resonant based sensors.

This paper presents a novel biosensor structure consisting of a resonator placed at the top wall of a microchannel (Resonator-on-Microchannel: RoM). The proposed biosensor structure is aimed to be used for real-time gravimetric detection of microscale biological targets in liquid environment by tracking the resonance frequency change of the system as the sought particles/cells are attached to the resonator surface. The damping effects are minimized with the help of the proposed resonator placement as well as the hydrophobic coating applied around the resonator gaps. Measurement results show that the quality factor drops only by a factor of 0.5 in liquid environment, validating the operation of the structure. (C) 2016 The Authors. Published by Elsevier Ltd.