I-shaped thermally actuated VHF resonators with submicron components

Hall, Harris J.; Rahafrooz, Amir; Brown, Joseph J.; Bright, Victor M.; Pourkamali, Siavash

doi:10.1016/j.sna.2012.12.006

Cited by 11 publications

(10 citation statements)

References 16 publications

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“…For real-time monitoring, the sensing Wheatstone bridge (WB) of the cantilever is connected to a homemade phase-locked loop (PLL) circuit [14,15]. However, the phenomenon of the asymmetric resonance response, of the in-plane excited cantilever is often observed with thermally excited cantilevers [7,8,16], and has not been analysed in details. Thus, in this work, different designs of the electrothermal cantilever resonators are investigated.…”

Section: Introductionmentioning

confidence: 99%

Analysis of asymmetric resonance response of thermally excited silicon micro-cantilevers for mass-sensitive nanoparticle detection

Bertke

Hamdana

et al. 2017

J. Micromech. Microeng.

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In this paper, the asymmetric resonance frequency (f0) responses of thermally in-plane excited silicon cantilevers for a pocket-sized, cantilever-based airborne nanoparticle detector (Cantor) are analysed. By measuring the shift of f0 caused by the deposition of nanoparticles (NPs), the cantilevers are used as a microbalance. The cantilever sensors are low cost manufactured from silicon by bulk-micromachining techniques and contain an integrated p-type heating actuator and a sensing piezoresistive Wheatstone bridge. f0 is tracked by a homemade phase-locked loop (PPL) for real-time measurements. To optimize the sensor performance, a new cantilever geometry was designed, fabricated and characterized by its frequency responses. The most significant characterisation parameters of our application are f0 and the quality factor (Q), which have high influences on sensitivity and efficiency of the NP detector. Regarding the asymmetric resonance signal, a novel fitting function based on the Fano resonance replacing the conventionally used function of the simple harmonic oscillator and a method to calculate Q by its fitting parameters were developed for a quantitative evaluation. To obtain a better understanding of the resonance behaviours, we analysed the origin of the asymmetric line shapes. Therefore, we compared the frequency response of the on-chip thermal excitation with an external excitation using an in-plane piezo actuator. In correspondence to the Fano effect, we could reconstruct the measured resonance curves by coupling two signals with constant amplitude and the expected signal of the cantilever, respectively. Moreover, the phase of the measurement signal can be analysed by this method, which is important to understand the locking process of the PLL circuit. Besides the frequency analysis, experimental results and calibration measurements with different particle types are presented. Using the described analysis method, decent results to optimize a next generation of Cantor are expected.

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Section: Introductionmentioning

confidence: 99%

Analysis of asymmetric resonance response of thermally excited silicon micro-cantilevers for mass-sensitive nanoparticle detection

Bertke

Hamdana

et al. 2017

J. Micromech. Microeng.

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“…Many opportunities exist for continuation of this work into CMOS-integrated heaters and other lab-on-a-chip applications, nanoscale vibration, and larger-scale operation such as in sonar or other acoustic devices. This technology provides a rich base for exploration of physical effects with increasing precision, and the impact of many effects such as the Thomson effect shifting hot spots due to electron flow [36], or the propagation of thermal waves as a mechanism to drive electromechanical resonance and oscillation [37], are completely open for exploration in this system.…”

Section: Discussionmentioning

confidence: 99%

Ultrathin thermoacoustic nanobridge loudspeakers from ALD on polyimide

et al. 2016

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The recent development of low-temperature (<200 °C) atomic layer deposition (ALD) for fabrication of freestanding nanostructures has enabled consideration of active device design based on engineered ultrathin films. This paper explores audible sound production from thermoacoustic loudspeakers fabricated from suspended tungsten nanobridges formed by ALD. Additionally, this paper develops an approach to lumped-element modeling for design of thermoacoustic nanodevices and relates the near-field plane wave model of individual transducer beams to the far-field spherical wave sound pressure that can be measured with standard experimental techniques. Arrays of suspended nanobridges with 25.8 nm thickness and sizes as small as 17 μm × 2 μm have been fabricated and demonstrated to produce audible sound using the thermoacoustic effect. The nanobridges were fabricated by ALD of 6.5 nm AlO and 19.3 nm tungsten on sacrificial polyimide, with ALD performed at 130 °C and patterned by standard photolithography. The maximum observed loudspeaker sound pressure level (SPL) is 104 dB, measured at 20 kHz, 9.71 W input power, and 1 cm measurement distance, providing a loudspeaker sensitivity value of ∼64.6 dB SPL/1 mW. Sound production efficiency was measured to vary proportional to frequency f and was directly proportional to input power. The devices in this paper demonstrate industrially feasible nanofabrication of thermoacoustic transducers and a sound production mechanism pertinent to submicron-scale device engineering.

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“…On the other hand, top-down fabrication approaches [20][21][22][23][24][25], among which E-beam lithography (EBL) is the most commonly used, involve producing high resolution masks on thinned-down silicon substrates and then etching away the unwanted parts in order to create desired nanoscale features. Despite allowing for control over the number and position of the features, it is a time-consuming serial route which is not suitable for high-volume manufacturing.…”

Section: Introductionmentioning

confidence: 99%

Self-controlled fabrication of single-crystalline silicon nanobeams using conventional micromachining

Mehdizadeh¹,

Rahafrooz²,

Pourkamali³

2014

Nanotechnology

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This paper reports on a low-cost top-down approach to the nano-precision fabrication of nanobeams on single-crystalline silicon using only conventional micromachining technology. The fabrication technique takes advantage of the crystalline structure of silicon for controllable feature size reduction of nanobeams with atomically smooth surfaces and sharp edges. Applying a deliberate rotational misalignment in a 2 μm resolution standard lithography process, followed by anisotropic wet etching of the silicon, nanobeams with well uniform widths as small as ∼85 nm are fabricated on thin SOI substrates. As a proof of concept for the incorporation of such nanobeams within electromechancial structures, we successfully demonstrate thermally actuated resonators that show very high frequencies (close to 50 MHz).

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I-shaped thermally actuated VHF resonators with submicron components

Cited by 11 publications

References 16 publications

Analysis of asymmetric resonance response of thermally excited silicon micro-cantilevers for mass-sensitive nanoparticle detection

Analysis of asymmetric resonance response of thermally excited silicon micro-cantilevers for mass-sensitive nanoparticle detection

Ultrathin thermoacoustic nanobridge loudspeakers from ALD on polyimide

Self-controlled fabrication of single-crystalline silicon nanobeams using conventional micromachining

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