Novel Test Fixture for Characterizing MEMS Switch Microcontact Reliability and Performance

Mahanta, Protap Kumar; Anwar, Farhana; Coutu, Ronald A.

doi:10.3390/s19030579

Cited by 8 publications

(7 citation statements)

References 23 publications

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“…In addition, a large F c helps to break contaminating films and enhances the stability of R c from cycle to cycle [35]. Experimental data suggest the minimum required value of 100 µN per contact [29][30][31]33,38].…”

Section: Methodsmentioning

confidence: 99%

“…However, this assumption is valid for clean surfaces. For rea tacts, exceeding the threshold of 100 µN allows one to expect a more significant dec in Rc [29][30][31]33,38] and its stabilization due to the breaking of contaminating films restoring force grows from 18 to 59 µN and is approximately half of Fc, which ensu reliable overcoming of stiction. An additional benefit is the reduction in Vpull-in from 50 V. These results are achieved by reducing the bump height from 0.5 to 0.2 µm an gap from 1.5 to 0.6 µm as well as by increasing the cantilever thickness from 2.0 to 4.…”

Section: Choosing the Vertical Dimensionsmentioning

confidence: 99%

“…The problem is well understood by the MEMS community. The operation of microscopic contacts is thoroughly investigated using indenters [29][30][31], scanning probe microscopes [32,33], and homemade facilities [34][35][36][37][38]. It is demonstrated that the contact resistance rapidly decreases with increasing the force and then reaches saturation.…”

Section: Introductionmentioning

confidence: 99%

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Design Guideline for a Cantilever-Type MEMS Switch with High Contact Force

Uvarov,

Belozerov

2023

Micro

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Micromechanical switches are of significant interest for advanced radio frequency and microwave systems, but their practical implementation is limited by low reliability. Electrodes of a microscopic size develop weak contact force that leads to high and unstable contact resistance. The force is typically increased by using a sophisticated switch design with extended lateral dimensions, although a simple and compact cantilever is more preferable. The paper describes for the first time a comprehensive approach to enhance the force of an electrostatically actuated switch. The strategy is applied to a miniature device based on a 50 µm long cantilever. The contact force is increased from 10 to 112 µN, making the switch strong enough to achieve low and stable contact resistance. The restoring force is also enhanced in order to ensure reliable de-actuation. The growth of forces is accompanied by a reduction in the pull-in voltage. Connecting several cantilevers in parallel and manipulating the number and position of contact bumps additionally improves the force and mechanical stability of the switch. An optimal design contains a triple cantilever with two bumps. It provides 50% higher force per contact compared to the single-cantilever switch at the same pull-in voltage and keeps the advantages of a miniature device. The proposed design strategy may be used for building reliable MEMS switches.

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Section: Methodsmentioning

confidence: 99%

Section: Choosing the Vertical Dimensionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design Guideline for a Cantilever-Type MEMS Switch with High Contact Force

Uvarov,

Belozerov

2023

Micro

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“…Based on the stiffness and density of Ni (ρ Ni ), the resonance frequency (f resonance ) can be calculated. Resonance frequency determines the highest actuation frequency (f actuation ) [23,24]. Figure 4a shows beam resonance frequency variation.…”

Section: Beam Modeling For Microcontact Test Structurementioning

confidence: 99%

Improved Test Fixture for Collecting Microcontact Performance and Reliability Data

Nandy,

Coutu,

Mahbub

2024

Micromachines

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Microelectromechanical systems (MEMS) ohmic contact switches are considered to be a promising candidate for wireless communication applications. The longevity of MEMS switches is directly related to the reliability and performance of microcontacts. In this work, an improved microcontact test fixture with high actuation rates (KHz) and highly precise position control (nm) and force (nN) control was developed. Here, we collected microcontact performance data from initial contact tests (ICT) and microcontact reliability data from cold switched tests (CST). To perform these tests with our test fixture, we fabricated MEMS microcontact test structures with relatively high Young’s modulus electroplated Nickel (Ni)-based, fixed–fixed beam structure with Au/RuO2 bimetallic microcontacts. These structures were characterized for forces ranging from 200–1000 µN in ICT tests. In a CST test, the tested microcontact survived more than 200 million cycles at a 1 KHz cycle rate, with a stable contact resistance value ranging between 3.8–5.2 Ω. These experiments validate the potentiality of our microcontact test fixture, and will facilitate further investigation on advanced microcontacts to enhance the MEMS switch’s reliability.

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“…like the phase change material, transitional metal oxide, etc. [101][102][103][104][105]. For a good RF device, a low ON resistance (Ωs), a low OFF capacitance (fF), a low power consumption (µW-mW range), and a flat broad band response is required (up to 50 GHz).…”

Section: Design and Simulation Of Lc-cnt-based Rf Devicesmentioning

confidence: 99%

Nematic Liquid Crystal Composite Materials for DC and RF Switching

2019

Self Cite

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Liquid Crystals (LCs) are widely used in display devices, electro-optic modulators, and optical switches. A field-induced electrical conductivity modulation in pure liquid crystals is very low which makes it less preferable for direct current (DC) and radio-frequency (RF) switching applications. According to the literature, a conductivity enhancement is possible by nanoparticle doping. Considering this aspect, we reviewed published works focused on an electric field-induced conductivity modulation in carbon nanotube-doped liquid crystal composites (LC-CNT composites). A two to four order of magnitude switching in electrical conductivity is observed by several groups. Both in-plane and out-of-plane device configurations are used. In plane configurations are preferable for micro-device fabrication. In this review article, we discussed published works reporting the elastic and molecular interaction of a carbon nanotube (CNT) with LC molecules, temperature and CNT concentration effects on electrical conductivity, local heating, and phase transition behavior during switching. Reversibility and switching speed are the two most important performance parameters of a switching device. It was found that dual frequency nematic liquid crystals (DFNLC) show a faster switching with a good reversibility, but the switching ratio is only two order of magnitudes. A better way to ensure reversibility with a large switching magnitude is to use two pairs of in-plane electrodes in a cross configuration. For completeness and comparison purposes, we briefly reviewed other nanoparticle- (i.e., Au and Ag) doped LC composite’s conductivity behavior as well. Finally, based on the reported works reviewed in this article on field induced conductivity modulation, we proposed a novel idea of RF switching by LC composite materials. To support the idea, we simulated an LC composite-based RF device considering a simple analytical model. Our RF analysis suggests that a device made with an LC-CNT composite could show an acceptable performance. Several technological challenges needed to be addressed for a physical realization and are also discussed briefly.

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Novel Test Fixture for Characterizing MEMS Switch Microcontact Reliability and Performance

Cited by 8 publications

References 23 publications

Design Guideline for a Cantilever-Type MEMS Switch with High Contact Force

Design Guideline for a Cantilever-Type MEMS Switch with High Contact Force

Improved Test Fixture for Collecting Microcontact Performance and Reliability Data

Nematic Liquid Crystal Composite Materials for DC and RF Switching

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