Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology

Lin, Cheng-Yang; Hsu, C. S.; Dai, Ching‐Liang

doi:10.3390/mi6111447

Cited by 16 publications

(16 citation statements)

References 26 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, Δ|S21| shows a significant difference between live and dead E. coli, especially in the frequency range below 10 GHz (nn = 3). The insertion loss Δ|S21| value also was comparable to previous studies CPW insertion loss measurement results [58,59]. Interestingly, heat-killed E. coli yields similar signals to the background for both |S11| and |S21|, while signals from live bacteria deviate from the background, especially for the insertion loss.…”

Section: S-parameter Measurements From Live and Dead E Colisupporting

confidence: 87%

Differentiation of live and heat-killed E. coli by microwave impedance spectroscopy

Multari

Palego

et al. 2018

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

The detection of bacteria cells and their viability in food, water and clinical samples is critical to bioscience research and biomedical practice. In this work, we present a microfluidic device encapsulating a coplanar waveguide for differentiation of live and heat-killed E.scherichiacoli cells suspended in culture media using microwave signals over the frequency range of 0.5 GHz-20 GHz. From small populations of ∼15 E. coli cells, both the transmitted (|S21|) and reflected (|S11|) microwave signals show a difference between live and dead populations, with the difference especially significant for |S21| below 10 GHz. Analysis based on an equivalent circuit suggests that the difference is due to a reduction of the cytoplasm conductance and permittivity upon cell death. The electrical measurement is confirmed by off-chip biochemical analysis: the conductivity of cell lysate from heat-killed E. coli is 8.22% lower than that from viable cells. Furthermore, protein diffusivity increases in the cytoplasm of dead cells, suggesting the loss of cytoplasmic compactness. These changes are results of intact cell membrane of live cells acting as a semipermeable barrier, within which ion concentration and macromolecule species are tightly regulated. On the other hand, the cell membrane of dead cells is compromised, allowing ions and molecules to leak out of the cytoplasm. The loss of cytoplasmic content as well as membrane integrity areis measurable by microwave impedance sensors. Since our approach allows detection of bacterial viability in the native growth environment, it is a promising strategy for rapid point-of-care diagnostics of microorganisms as well as sensing biological agents in bioterrorism and food safety threats.

show abstract

Section: S-parameter Measurements From Live and Dead E Colisupporting

confidence: 87%

Differentiation of live and heat-killed E. coli by microwave impedance spectroscopy

Multari

Palego

et al. 2018

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

show abstract

“…The AV for the MSS was 60 V. The MSS isolation was 36 dB at 40 GHz. Lin et al [ 16 ] employed the complementary metal oxide semiconductor (CMOS) process to develop a MSS with four inductors. The inductors were used to enhance the electrical properties for the MSS.…”

Section: Introductionmentioning

confidence: 99%

Manufacturing and Testing of Radio Frequency MEMS Switches Using the Complementary Metal Oxide Semiconductor Process

Tsai

Shih

Tsai

et al. 2021

Sensors

Self Cite

View full text Add to dashboard Cite

A radio frequency microelectromechanical system switch (MSS) manufactured by the complementary metal oxide semiconductor (CMOS) process is presented. The MSS is a capacitive shunt type. Structure for the MSS consists of coplanar waveguide (CPW) lines, a membrane, and springs. The membrane locates over the CPW lines. The surface of signal line for the CPW has a silicon dioxide dielectric layer. The fabrication of the MSS contains a CMOS process and a post-process. The MSS has a sacrificial oxide layer after the CMOS process. In the post-processing, a wet etching of buffer oxide etch (BOE) etchant is employed to etch the sacrificial oxide layer, so that the membrane is released. Actuation voltage for the MSS is simulated using the CoventorWare software. The springs have a low stiffness, so that the actuation voltage reduces. The measured results reveal that actuation voltage for the MSS is 10 V. Insertion loss for the MSS is 0.9 dB at 41 GHz and isolation for the MSS is 30 dB at 41 GHz.

show abstract

“…It has the potential to be used for breath analysis. CMOS-MEMS was used to produce micro-actuators [16,17] and microsensors [18][19][20]. This process allowed the integration of micro-devices and integrated circuits on a chip, which reduced noise and enhanced the micro-devices' performance.…”

Section: Introductionmentioning

confidence: 99%

Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS–MEMS Technique

et al. 2020

Self Cite

View full text Add to dashboard Cite

This study describes the fabrication of an ammonia gas sensor (AGS) using a complementary metal oxide semiconductor (CMOS)–microelectromechanical system (MEMS) technique. The structure of the AGS features interdigitated electrodes (IDEs) and a sensing material on a silicon substrate. The IDEs are the stacked aluminum layers that are made using the CMOS process. The sensing material; polypyrrole/reduced graphene oxide (PPy/RGO), is synthesized using the oxidation–reduction method; and the material is characterized using an electron spectroscope for chemical analysis (ESCA), a scanning electron microscope (SEM), and high-resolution X-ray diffraction (XRD). After the CMOS process; the AGS needs post-processing to etch an oxide layer and to deposit the sensing material. The resistance of the AGS changes when it is exposed to ammonia. A non-inverting amplifier circuit converts the resistance of the AGS into a voltage signal. The AGS operates at room temperature. Experiments show that the AGS response is 4.5% at a concentration of 1 ppm NH3; and it exhibits good repeatability. The lowest concentration that the AGS can detect is 0.1 ppm NH3

show abstract

Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology

Cited by 16 publications

References 26 publications

Differentiation of live and heat-killed E. coli by microwave impedance spectroscopy

Differentiation of live and heat-killed E. coli by microwave impedance spectroscopy

Manufacturing and Testing of Radio Frequency MEMS Switches Using the Complementary Metal Oxide Semiconductor Process

Low-Concentration Ammonia Gas Sensors Manufactured Using the CMOS–MEMS Technique

Contact Info

Product

Resources

About