Resonant Sensors for Microfluidic Applications

Niebelschütz, Florentina; Tonisch, Katja; Cimalla, V.; Brückner, Klemens; Stephan, Ralf; Hein, Matthias; Schober, Andreas; Ambacher, O.

doi:10.1557/proc-0951-e05-07

Cited by 3 publications

(10 citation statements)

References 4 publications

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“…In the low-pressure range (<1 bar), analysis of the damping behaviour was shown to be more sensitive [194,561]. ) in dependence on pressure [561].…”

Section: Resonant Microstructuresmentioning

confidence: 98%

Group III nitride and SiC based MEMS and NEMS: materials properties, technology and applications

Cimalla¹,

Pezoldt²,

Ambacher³

2007

J. Phys. D: Appl. Phys.

350

217

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With the increasing requirements for microelectromechanical systems (MEMS) regarding stability, miniaturization and integration, novel materials such as wide band gap semiconductors are attracting more attention. Polycrystalline SiC has first been implemented into Si micromachining techniques, mainly as etch stop and protective layers. However, the outstanding properties of wide band gap semiconductors offer many more possibilities for the implementation of new functionalities. Now, a variety of technologies for SiC and group III nitrides exist to fabricate fully wide band gap semiconductor based MEMS. In this paper we first review the basic technology (deposition and etching) for group III nitrides and SiC with a special focus on the fabrication of three-dimensional microstructures relevant for MEMS. The basic operation principle for MEMS with wide band gap semiconductors is described. Finally, the first applications of SiC based MEMS are demonstrated, and innovative MEMS and NEMS devices are reviewed.

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“…In the low-pressure range (<1 bar), analysis of the damping behaviour was shown to be more sensitive [194,561]. ) in dependence on pressure [561].…”

Section: Resonant Microstructuresmentioning

confidence: 98%

Group III nitride and SiC based MEMS and NEMS: materials properties, technology and applications

Cimalla¹,

Pezoldt²,

Ambacher³

2007

J. Phys. D: Appl. Phys.

350

217

View full text Add to dashboard Cite

show abstract

“…The anisotropic structuring of the AlN layers for magnetomotive MEMS/NEMS was realized by a similar ICP dry etching process as the one used for AlGaN/GaN but with a higher working pressure at room temperature 109.…”

Section: Fabrication Technologymentioning

confidence: 99%

“…Biocompatibility tests have shown an excellent suitability of AlN, which also provides adhesion without any adhesive agent 103. The mass loading of Δ m = 1.5 ng led to a significant frequency shift corresponding to S m = 0.24 kHz/pg 109.…”

Section: Sensor Applicationsmentioning

confidence: 99%

Micro‐ and nano‐electromechanical resonators based on SiC and group III‐nitrides for sensor applications

Brueckner

Niebelschuetz

Tonisch

et al. 2011

Physica Status Solidi (a)

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Wide-bandgap semiconductors represent an attractive option to meet the increasing demands of micro- and nano-electromechanical systems (MEMS/NEMS) by offering new functionalities, high stability, biocompatibility and the potential for miniaturization and integration. Here, we report on resonant MEMS and NEMS devices with functional layers of SiC, AlN and AlGaN/GaN heterostructures on different substrates, which have been investigated and analysed in the course of an interdisciplinary research focus programme of the German Research Foundation (DFG). The specific deposition and etching technologies necessary for the three-dimensional micro-structuring are explained. Further, the implementation of appropriate electromechanical transduction schemes is discussed. In case of SiC and AlN resonators, actuation and sensing was achieved by a magnetomotive scheme. A piezoelectric coupling scheme where the counter electrode is formed by the two-dimensional electron gas at the interface of the III/V heterostructure was realized for the AlGaN/GaN resonators. Thus, flexural and longitudinal vibration modes were excited and characterized using electrical and optical techniques. The measured key parameters of resonant frequency and quality factor are related to geometry, material and environmental parameters using analytical and finite element (FE) models. Finally, potential sensor applications are experimentally investigated

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“…According to equation (7), ρ 0 (p) leads to a pronounced increase of Q(p) below a threshold value p thr of about 500 Pa; the exact value of p thr , which depends on the geometry and the material of the resonator, marks the transition from viscous to molecular flow as discussed in relation to equation (8). Below p thr , the Q-factor displays a high sensitivity on pressure, ∂ log(Q)/∂ log(p) (figure 9, righthand scale).…”

Section: Pressure Dependences Of the Quality Factor And Resonant Freq...mentioning

confidence: 99%

“…In all cases, high resonant frequencies and high quality factors are beneficial for high sensitivity. Compared to vacuum, sensors working under ambient conditions or even in liquid environment [8,9] exhibit strongly reduced Q-factors, necessitating optimized geometries and materials.…”

Section: Introductionmentioning

confidence: 99%

Strain- and pressure-dependent RF response of microelectromechanical resonators for sensing applications

Brueckner

Cimalla

Niebelschütz

et al. 2007

J. Micromech. Microeng.

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MEMS resonators bear great potential for applications as RF sensors, filters and oscillators, e.g., in life sciences or information technology. A semiconductor fabrication process has been applied to prepare resonant AlN and SiC beams operating at frequencies between 0.1 and 2.1 MHz. The metallized beams were actuated in a permanent magnetic field of about 0.5 T by the Lorentz force. For systematic studies of the resonant frequencies and quality factors, the induced voltage was measured using time domain and frequency domain techniques. Resonator geometry, material and ambient pressure were varied to attain a generalized understanding of the RF performance. The dependence of the resonant frequency on tensile axial strain has been derived analytically and extended to include highly strained beams. Based on these formulas, accurate detection of the residual layer strain after fabrication is presented. To describe the quality factor a chain of beads model has been applied successfully. The influences of the beam width and the pressure-dependent viscosity on the model parameters are analyzed.

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Resonant Sensors for Microfluidic Applications

Cited by 3 publications

References 4 publications

Group III nitride and SiC based MEMS and NEMS: materials properties, technology and applications

Group III nitride and SiC based MEMS and NEMS: materials properties, technology and applications

Micro‐ and nano‐electromechanical resonators based on SiC and group III‐nitrides for sensor applications

Strain- and pressure-dependent RF response of microelectromechanical resonators for sensing applications

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