MEMS near-DC to RF capacitive series switches

Rottenberg, Xavier; Geerlings, J.; Mertens, R.; Nauwelaers, Bart; Raedt, W. De; Tilmans, H.A.C.

doi:10.1109/euma.2003.341126

Cited by 9 publications

(13 citation statements)

References 10 publications

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“…For example, ST microelectronics introduced a thermally actuated MEMS switch which has 0.18 dB insertion loss at 2 GHz [3]. An electrostatic capacitive switch is introduced by IMEC researchers which has very high on/off ratio [4]. But, it might be subject to premature failure resulting from the adhesive force and the micro-welding of the two contact metal layers [5].…”

Section: Introductionmentioning

confidence: 98%

Design and simulation of a thermally actuated MEMS switch for microwave circuits

Zhang

Zaghloul

2009

Int J RF and Microwave Comp Aid Eng

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The design, modeling, and optimization of a novel, thermally actuated CMOS-MEMS switch are presented in this article. This series capacitive MEMS switch solves the substrate loss and down-state capacitance degradation problems commonly plaguing MEMS switches. The switch uses finger structure for capacitive coupling. The vertical bending characteristic of bimorph cantilever beams under different temperatures is utilized to turn the switch on and off. A set of electrical, mechanical, and thermal models is established, and cross-domain electro-thermo-mechanical simulations are performed to optimize the design parameters of the switch. The fabrication of the switch is completely CMOS-process compatible. The design is fabricated using the AMI 0.6 lm CMOS process and a maskless reactive-ion etching process. The measured results show the insertion loss and isolation are 1.67 and 33 dB, respectively, at 5.4 GHz, and 0.36 and 23 dB at 10 GHz. The actuation voltage is 25 V and the power consumption is 480 mW. This switch has a vast number of applications in the RF/microwave field, such as configurable voltage control oscillators, filters, and configurable matching networks.

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Section: Introductionmentioning

confidence: 98%

Design and simulation of a thermally actuated MEMS switch for microwave circuits

Zhang

Zaghloul

2009

Int J RF and Microwave Comp Aid Eng

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“…The stress gradient problem is especially severe in the case of cantilever beams (clamped-free) that are the preferred implementation for capacitive series devices. We solved this problem in [8] by adding a restraining bridge (clamped-clamped) at the tip of the cantilever beam, perpendicular to the signal line. Drawback of this structure is the introduction of transversal slots in the ground planes under the restraining bridge.…”

Section: Introductionmentioning

confidence: 99%

Compact and high-accuracy RF MEMS capacitive series devices

Rottenberg

Nauwelaers

Raedt

et al. 2005

MEMS/MOEMS Components and Their Applications II

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MEMS technology is presented as a promising technology to realize high Q variable capacitors and RF switches with high performance and with high levels of integration. These devices are key elements for systems like phase shifters, tunable filters and matching networks. However, the reliability and the yield of the RF MEMS devices remain the key limiting factors holding the MEMS technology from spreading in the industrial applications. From a RF designer's point of view, reliability and yield are closely related to the accuracy of the definition of the up-and downstate capacitances of the devices. In this paper, we propose a novel compact series capacitive structure with improved predictability and RF performance. The new design mimics a clamped-clamped bridge to lower its sensitivity to the process-induced stress gradient in the up-state. The shape of the device and its consequent parameters, e.g. up-and down-capacitances, are thus more accurately defined even in presence of non-ideal clamping conditions. Unlike the series switchable capacitors with transverse restraining bridge, the novel device does not suffer from high frequency parasitic resonances. Finally, the novel device implements the floating top metal. This allows accurately defining the down-state capacitance of the design at will. Boosted series capacitive switches with inline-restrained cantilever beams have been realized and measured. The isolation is better than 20dB until 1GHz without optimization. The insertion loss in the down-state is better than 0.2dB in the range 1-20GHz. It further slowly and continuously decays to reach 0.4dB at 40GHz without any resonances.

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“…1 The capacitance-voltage (C-V) curve of the switch changes over the device lifetime due to reliability problems and this received much attention in the literature. [2][3][4][5][6][7][8][9][10] While charging mechanism has been reported as the primary reliability problem of capacitive switches, the C-V curve instability can also occur due to mechanical degradation of the movable electrode. The device cross section and ideal C-V curve of a switch used in this work are shown in Fig.…”

mentioning

confidence: 99%

“…If parasitic charge in the device (e.g., in the dielectric on top of the central line) or around the device (e.g., in substrate or in the CPW gaps) due to bias stress exist and acts on the movable electrode, the whole C-V curve can shift on the voltage axis toward the positive or negative direction or narrow when the threshold voltages decreases in magnitude. [2][3][4][5][6] The narrowing effect has also been attributed to mechanical degradation of the movable electrode. [6][7][8] Currently, many capacitive switch technologies are presented in the literature where variations in threshold voltages are observed.…”

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confidence: 99%

Experimental isolation of degradation mechanisms in capacitive microelectromechanical switches

Olszewski

Houlihan

Ryan

et al. 2012

Applied Physics Letters

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DC and bipolar voltage stresses are used to isolate mechanical degradation of the movable electrode from charging mechanism in microelectromechanical capacitive switches. Switches with different metals as the movable electrode were investigated. In titanium switches, a shift in the pull-in voltages is observed after dc stressing whereas no shift occurs after the bipolar stressing, which is to be expected from charging theory. On switches with similar dielectric but made of aluminium, the narrowing effect occurs regardless if dc or bipolar stressing is used, which indicates the mechanical degradation as the mechanism responsible.

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MEMS near-DC to RF capacitive series switches

Cited by 9 publications

References 10 publications

Design and simulation of a thermally actuated MEMS switch for microwave circuits

Design and simulation of a thermally actuated MEMS switch for microwave circuits

Compact and high-accuracy RF MEMS capacitive series devices

Experimental isolation of degradation mechanisms in capacitive microelectromechanical switches

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