Design and Fabrication of Reliable Power Efficient Bistable MEMS Switch Using Single Mask Process
22 Jul 2020-IEEE\/ASME Journal of Microelectromechanical Systems (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 29, Iss: 5, pp 1225-1233
TL;DR: In this article, a bistable DC switch based on buckled beams and thermal actuation has been designed, fabricated and characterised, and the switch retains functionality even after 5 million switching cycles.
Abstract: A bistable DC switch based on buckled beams and thermal actuation has been designed, fabricated and characterised. The buckled beams, which require very low actuation force and provide a sufficiently large contact force, are designed based on a parametric study. U-shaped thermal actuators are designed to provide the actuation force with minimum electrical power. The compact switch is fabricated using a simple single mask process on a SOI wafer. The average switching power is measured to be 60 $mW$ , while the average switching delay is 350 ${\mu }s$ . The power-delay product of about $20~{\mu }J$ is the lowest reported so far for bistable MEMS switches based on thermal actuation. The switch retains functionality even after 5 million switching cycles. [2020-0026]
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TL;DR: In this article, the authors studied the limit point behavior of a double-clamped, initially curved beams coupled via a rigid truss at their respective centres, when subjected to a distributed electrostatic load.
9 citations
TL;DR: In this paper, a 3D digital actuator is used to realize planar motions of micro-objects, which could be implemented in several applications where micro-positioning tasks are needed such as micro-component manufacturing/assembly, biomedicine, scanning microscopy, etc.
Abstract: In this paper, a novel micro-positioning device based on a 3D digital actuator is presented. The proposed system allows realizing planar motions of micro-objects, which could be implemented in several applications where micro-positioning tasks are needed such as micro-component manufacturing/assembly, biomedicine, scanning microscopy, etc. The device has three degrees of freedom, and it is able to achieve planar motions of a mobile plate in the xy-plane at two different levels along the z-axis. It consists of a hexagonal mobile part composed of a permanent magnet that can reach twelve discrete positions distributed between two z-axis levels (six at each level). Two different approaches are presented to perform positioning tasks of the plate using the digital actuator: the stick-slip and the lift-mode approaches. A comparison between these two approaches is provided on the basis of the plate displacement with respect to different current values and conveyed mass. It was observed that for a current of 2 A, the actuator is able to displace a mass of 1.15 g over a distance of 0.08 mm. The optimal positioning range of the planar device was found to be ±5.40 mm and ±7.05 mm along the x- and y-axis, respectively.
3 citations
TL;DR: In this article , a double-layer electrothermal MEMS S&A device with a bistable mechanism is presented, which can drive the barrier to an arming position actively.
Abstract: Considering the safety of ammunition, safety and arming (S&A) devices are usually designed in pyrotechnics to control energy transfer through a movable barrier mechanism. To achieve both intelligence and miniaturization, electrothermal actuators are used in MEMS S&A devices, which can drive the barrier to an arming position actively. However, only when the actuators’ energy input is continuous can the barrier be stably kept in the arming position to wait for ignition. Here, we propose the design and characterization of a double-layer electrothermal MEMS S&A Device with a bistable mechanism. The S&A device has a double-layer structure and four groups of bistable mechanisms. Each bistable mechanism consists of two V-shape electrothermal actuators to drive a semi-circular barrier and a pawl, respectively, and control their engagement according to a specific operation sequence. Then, the barrier can be kept in the safety or the arming position without energy input. To improve the device’s reliability, the four groups of bistable mechanisms are axisymmetrically placed in two layers to constitute a double-layer barrier structure. The test results show that the S&A device can use constant-voltage driving or the capacitor–discharge driving to drive the double-layer barrier to the safety or the arming position and keep it on the position passively by the bistable mechanism.
2 citations
01 Oct 2008
TL;DR: In this paper, a latching RF MEMS switch has been fabricated in a multi-user polysilicon surface micromachining process using 5 V, 35 mA thermal actuation for < 500 mus to toggle between states and a compliant latching mechanism to hold the state in the absence of applied bias.
Abstract: A latching RF MEMS switch has been fabricated in a multi-user polysilicon surface micromachining process. The switch uses 5 V, 35 mA thermal actuation for < 500 mus to toggle between states and a compliant bistable latching mechanism to hold the state in the absence of applied bias. The switch, including probe pads, measures 1 mm2 and has <0.4 dB insertion loss, >25 dB return loss, and >75 dB isolation at 1 GHz. The switch has potential applications in low duty-cycle, low power RF tuning and switching applications.
2 citations
TL;DR: In this paper , a new structure for low-loss and high-isolation radio-frequency microelectromechanical systems (RF MEMS) switches is presented, which is composed of two actuators: an electrothermal actuator for actuation of the switch from OFF to ON state and an electrostatic actuator to hold the switch at ON state.
Abstract: A new structure for low‐loss and high‐isolation radio‐frequency microelectromechanical systems (RF MEMS) switches is presented. The high contact force of the switch leads to very small ranges for contact resistance which is the main constrain of DC‐contact RF MEMS switches. The contact resistance of the switch is 27 mΩ leading to negligible thermal noise which is one of the most important parameters for devices operating at RF front‐ends immediately after the antenna where there is not any active stage. The switch is composed of two actuators: an electrothermal actuator for actuation of the switch from OFF to ON state and an electrostatic actuator to hold the switch at ON state. The insertion loss, return loss, and isolation of the switch for frequencies below 70 GHz are −0.35, −20, and −10 dB, respectively. The contact force and contact resistance of the switch are 0.93 mN and 0.027 Ω, respectively. Electrothermal and electrostatic actuators require 0.91 and 50 actuation voltages, respectively. During the ON‐state, the power consumption of the switch is near zero. The low contact resistance and high‐isolation characteristics of the switch make it very suitable for mobile front‐ends.
1 citations
References
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01 Jan 1999
TL;DR: In this article, the authors describe in-plane microactuators fabricated by standard microsensor materials and processes that can generate forces up to about a milli-newton.
Abstract: This paper describes in-plane microactuators fabricated by standard microsensor materials and processes that can generate forces upto about a milli-newton. They operate by leveraging the deformations produce by localized thermal stresses. Analytical and finite element models of device performance are presented along with measured results of fabricated devices using electroplated Ni, LPCVD polysilicon, and p++ Si as structural materials. A maskless process extension for incorporating thermal and electrical isolation is outlined. Test results show that static displacements of =lo pm can be achieved with power dissipation of =lo0 mW, and output forces >300 pN can be achieved with input power <250 mW. It is also shown that cascaded devices offer a 4X improvement in displacement. The displacements are rectilinear, and the output forces generated are lox-1OOX higher than those available from other comparable options. This performance is achieved at much lower drive voltages than necessary for electrostatic actuation, indicating that bentbeam thermal actuators are suitable for integration in a variety of microsystems.
153 citations
TL;DR: In this paper, a DRIE-through-etched laterally bistable MEMS relay for power applications is presented, with a primary emphasis on the design and modeling of its U-shaped transient thermal actuators, and a secondary emphasis on its contact element.
Abstract: This paper reports a deep-reactive ion etching (DRIE)-through-etched laterally bistable MEMS relay for power applications, with a primary emphasis on the design and modeling of its U-shaped transient thermal actuators, and a secondary emphasis on the design and fabrication of its contact element. In this relay, a contact crossbar is carried by a curved-beam bistable mechanism , which is toggled by transient U-shaped thermal actuators with their hot beam adiabaticly heated by electrical pulses. Each U-shaped thermal actuator comprises uniform-thickness hot and cold beams with a gap between them so they bend differently. This paper develops both a basic model and a complete model for the actuator that are verified by Finite Element Analysis and serve as effective design tools. The DRIE process creates nonideal etched surfaces, which pose challenges for good relay contacts. Both contact design and process development are discussed to help alleviate this problem. The fabricated relay exhibits a minimum total on-state resistance of 60 m/spl Omega/, and a maximum current carrying capacity of 3 A. It switches with a 1 ms actuation pulse, and a maximum 5 Hz repetition rate.
127 citations
"Design and Fabrication of Reliable ..." refers background or result in this paper
...This is due to asymmetry in F − d curve in terms of force, as reported in [8]....
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...[7], as it requires less actuation force than the structure used in [8]....
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TL;DR: In this paper, the authors defined the ideal switch as a device having virtually no insertion loss (Ron = 0 Ω) over a wide frequency range, very high isolation [off-state capacitance (Coff)] = 0 fF), extremely high linearity (IIP2 and IIP3 → infinite), medium-to high-power handling (100 mW to 1 kW), and no dc power consumption.
Abstract: The RF community has long been searching for the ideal switch since the birth of electronics, and it is defined as a device having virtually no insertion loss (Ron = 0 Ω) over a wide frequency range, very high isolation [off-state capacitance (Coff)] = 0 fF), extremely high linearity (IIP2 and IIP3 → infinite), medium- to high-power handling (100 mW to 1 kW), and no dc power consumption. Our entire RF infrastructure ecosystem, from communication system networks, to satellite systems, to wideband spectral analysis, to instrumentation and radar systems, uses a variety of switches for signal routing and control (attenuation, phase shifting, etc.). The ideal switch was achieved long time ago using electromechanical relays, and even after nearly 100 years, it is still the best RF switch ever made from an electrical perspective [1]. It has very low insertion loss (Ron <;1 Ω), very high isolation (Coff of few fF), very high linearity and high power handling (100 mW to 50 W). However, it is bulky, expensive, and has an average lifetime of few million cycles.
118 citations
"Design and Fabrication of Reliable ..." refers background in this paper
...M ICRO electromechanical system (MEMS) switches have evolved over the last few decades to commercially available products [1]....
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TL;DR: In this paper, a bistable microelectromechanical switch for an implantable lead electrode multiplexer application was designed, which is based on a single mask process.
Abstract: In this paper, we have designed a bistable microelectromechanical switch for an implantable lead electrode multiplexer application. Fabrication is based on a single mask process. State changes require an 18 V pulse to the actuators consuming only 0.2 nJ energy. The switch does not consume any energy in either the ON or the OFF state. Total chip size including bond pads is approximately 1.5 mm /spl times/ 1.5 mm. The initial contact resistance is below 5 /spl Omega/ with a contact force in the order of 10 /spl mu/N. The contact resistance stays consistently below 30 /spl Omega/ for the first 40 000 cycles. Breakdown voltage between the two contact members in OFF state is 300 V. We plan to further investigate applicability of this switch in the biomedical field.
99 citations
"Design and Fabrication of Reliable ..." refers background or methods in this paper
...Bistability in laterally moving switches is achieved by either latching mechanism [4]–[6] or buckled beam [7]–[10]....
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...hand, for wh = 3 μm as in [7], there is a significant reduction in actuation force with increasing g....
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...2 with the geometrical parameters used in [7], with wh = 3 μm, wb = 10 μm, lh = 100 μm, lb = 300 μm, x0 = 8 μm, g = 10 μm and t = 50 μm....
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...[7], as it requires less actuation force than the structure used in [8]....
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...The F − d curve of reference buckled beam (solid line) [7] and the beam designed in this work (dashed line)....
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TL;DR: In this article, a thermally actuated latching wideband RF microelectromechanical systems (MEMS) switch is presented, which employs two thermal actuators connected to two thin metal arms which serve as signal lines of coplanar waveguide switch.
Abstract: Here, a new thermally actuated latching wideband RF microelectromechanical systems (MEMS) switch is presented. The switch employs two thermal actuators connected to two thin metal arms which serve as signal lines of coplanar waveguide switch. The actuators pull the thin arms sequentially, and latch the switch. The switch can be actuated on and off by using either short voltage or current pulses. Using a dielectric bridge (nitride) as an interface between the actuators and the thin arms, the RF circuitry is separated from DC actuators, allowing wide-band operation. The switch demonstrates an excellent wideband RF performance with an insertion loss of better than 0.3 dB up to 20 GHz and better than 0.8 dB up to 40 GHz. The return loss and isolation of the switch is better than 20 dB for the entire frequency band. The switch also has a very satisfactory repeatability with better than 0.1-dB variation in insertion loss and less than 1-dB variation in return loss and isolation at 30-dB level up to 6000 times switching cycles. The switch has been also successfully tested for RF power handling capability up to 40 dBm. The proposed switch has very simple RF structure which makes it an ideal candidate to be integrated in the form of more complex circuitry. An application of the proposed switch for a band selection network which is used in multiband transceivers has been presented here.
74 citations