Evaluation of Creep in RF MEMS Devices

Gils, Mark van; Bielen, J.A.; Mcdonald, G.

doi:10.1109/esime.2007.360033

Cited by 33 publications

(15 citation statements)

References 10 publications

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“…In addition, previous work on aluminum switches showed that the contact stress used in this work ͑i.e., stress time, ambient temperature, and stress voltage magnitude͒ cannot cause significant mechanical degradation of the membrane. 9,10 Moreover, from the selfactuation experiment we can observe that the physical mechanism is independent of the stress voltage polarity. This strongly indicates that the charge trapping ͑uniform or nonuniform͒ due to dielectric conduction or air ionization is not the physical mechanism responsible.…”

Section: Fig 1 ͑A͒mentioning

confidence: 97%

“…7 and 8 it was suggested that charging can also occur before the membrane reaches the dielectric. Further study 9 has also associated the narrowing with the ON-state bias stress; however, mechanical creep was indicated as a source. Finally, recent work 10 presented experimentally that there can be two distinct mechanisms responsible for the C-V narrowing.…”

mentioning

confidence: 99%

“…The C-V curve changes during switch operation, and this has received much attention in the literature. [2][3][4][5][6][7][8][9][10][11] Early work showed that the forward and reverse thresholds shift in the same direction. 2,3 This is referred to as C-V shift and was interpreted solely as charge trapping in the dielectric ͑dielectric charging͒ during the ON state of the switch.…”

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confidence: 99%

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A study of capacitance-voltage curve narrowing effect in capacitive microelectromechanical switches

Olszewski¹,

Duane²,

O’Mahony³

2008

Applied Physics Letters

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Section: Fig 1 ͑A͒mentioning

confidence: 97%

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confidence: 99%

mentioning

confidence: 99%

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A study of capacitance-voltage curve narrowing effect in capacitive microelectromechanical switches

Olszewski¹,

Duane²,

O’Mahony³

2008

Applied Physics Letters

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“…Creep can directly affect the operational characteristic, e.g. through a shift in pull-in voltage of an RF-MEMS switch which results in a reduced power handling [2]. Whereas fatigue effects may pose less of a problem than expected at small geometrical length scales [3], the detrimental influence of creep seems to increase upon miniaturization [3].…”

Section: Reliability and Time-dependent Mechanicsmentioning

confidence: 99%

Mechanically probing time-dependent mechanics in metallic MEMS

Hoefnagels

Bergers

Delhey

et al. 2011

MEMS and Nanotechnology, Volume 2

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The reliability of metallic micro-electromechanical systems (MEMS) depends on time-dependent deformation such as creep. To this end, a purely mechanical experimental methodology for studying the time-dependent deformation of free-standing microbeams has been developed. It is found most suitable for the investigation of creep due to the simplicity of sample handling and preparation and setup design, whilst maximizing long term stability and displacement resolution. The methodology entails the application of a constant deflection to a μm-sized free-standing aluminum cantilever beam for a prolonged period of time. After this load is removed, the deformation evolution is immediately recorded by acquiring surface height profiles through confocal optical profilometry. Image correlation and an algorithm based on elastic beam theory are applied to the full-field beam profiles to yield the tip deflection as a function of time. The methodology yields the tip deflection as function of time with ~3 nm precision.

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“…They were not able to identify the effect of beam thickness on the Young's modulus and the yield stress. In another study [26], the effect of creep on a capacitive RF-MEMS switch with polycrystalline thin film electrodes was investigated by electrostatic experiments and numerical simulations. The material used in the experiments was considered to be the same as that in [25].…”

Section: Introductionmentioning

confidence: 99%

Crystal plasticity based modeling of time and scale dependent behavior of thin films

Ertürk¹,

Gao²,

Bielen³

et al. 2013

GAMM-Mitteilungen

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The micro and sub-micro scale dimensions of the components of modern high-tech products pose challenging engineering problems that require advanced tools to tackle them. An example hereof is time dependent strain recovery, here referred to as anelasticity, which is observed in metallic thin film components of RF-MEMS switches. Moreover, it is now well known that the properties of a thin film material strongly depend on its geometrical dimensions through so-called size effects. A strain gradient crystal plasticity formulation (SGCP) was recently proposed [1][2][3][4], involving a back stress in terms of strain gradients capturing the lattice curvature effect. In the present work, the SGCP model is used in a realistic simulation of electrostatic bending of a free standing thin film beam made of either a pure fcc metal or a particle strengthened Al-Cu alloy. The model capabilities to describe the anelastic and plastic behavior of metallic thin films in comparison with experimentally available data are thereby assessed. Simulation results show that the SGCP model is able to predict a macroscopic strain recovery over time following the load removal. The amount of the anelastic relaxation and the accompanying relaxation times result from the rate dependent modeling approach, the basis of which is phenomenological only. The SGCP model is not fully capable of describing the permanent deformations in an alloy thin beam as observed in electrostatic experiments. Hence, to incorporate realistic time constants and the influence of the microstructure into the mechanical behavior of the thin film material, an improved constitutive law for crystallographic slip is necessary within the SGCP formulation.

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Evaluation of Creep in RF MEMS Devices

Cited by 33 publications

References 10 publications

A study of capacitance-voltage curve narrowing effect in capacitive microelectromechanical switches

A study of capacitance-voltage curve narrowing effect in capacitive microelectromechanical switches

Mechanically probing time-dependent mechanics in metallic MEMS

Crystal plasticity based modeling of time and scale dependent behavior of thin films

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