Contactless four-terminal MEMS variable capacitor for capacitive adiabatic logic

Abstract

This paper reports the design, energy recovery and logical functionality modelling of four-terminal MEMS comb-drive devices for capacitive adiabatic logic (CAL). The proposed electromechanical element consists of the moving mass with two insulated electrodes and two fixed electrodes. The two pairs of fixed and moving electrodes form an input and an output comb-drive capacitive transducers. The voltage across the input port allows us to control the capacitance of the output port. The developed contactless four-terminal design is simulated in Coventor MEMS+® software. In order to speed-up transient simulation of numerous devices in an electrical Spice simulator, the obtained electrical and mechanical characteristics are used to fit our Verilog-A analytical compact model. Spice-simulation results demonstrate CAL logical functionalities using cascadable power clock scheme, i.e. logic states differentiation and cascadability. Also we show that MEMS-based calculation is energy efficient, for example, in a chain of four buffers, 99.1% of the energy transferred to the device is recovered for later use when devices operate at 25 Hz. The non-recoverable energy is mainly dissipated by mechanical damping during the logic state transition from high to low level and can be removed by using retractable power clocks. For this mm-scale device the energy dissipated per operation is in the order of one pJ. This is still far from the energy dissipated by a nm-scale FET transistor, which is of the order of 10's aJ. However, for the contactless design constant electric field scaling is possible and the energy dissipation decreases proportionally to the cube of the size. Finally, the difference between the signal energy and the distinguish energy in MEMS-based adiabatic logic is discussed.

MEMS four-terminal variable capacitor for low power capacitive adiabatic logic with high logic state differentiation

“…When adiabatic conditions are satisfied, most of the provided energy (89%) is recovered after one cycle. This is a bit less than the non-contact device we have presented in [19]. However, the logic state differentiation has been dramatically improved from a few percents to more than 50%.…”

“…In order to avoid the resistive contact in the on-state and to reduce the dynamic dissipation, a purely capacitive electromechanical switch could be a better solution [18]. Based on this new paradigm, the so-called Capacitive Adiabatic Logic (CAL), Galisultanov et al have detailed in [19] the concept of a fully contact-less electromechanical device for the CAL. In this paper we described new four-terminal variable capacitors (FTVC) for the CAL that still have a contact zone but present several major advantages, like a better differentiation between a "0" and a "1" logic state, a higher frequency of operation or a smaller area.…”

On the implementation of adaptive sliding mode robust controller in the stabilization of electrically actuated micro-tunable capacitor

“…Consequently, the overall equivalent stiffness of the suspended electrode system is 4 , where E , 3 12 I bh  , and L represent the Young's modulus of elasticity, the cross-sectional moment of inertia, and the arm length, respectively, and b and h are both the width and thickness of each arm, correspondingly. For simplicity, we assumed that the thickness of all four arms is the same as the thickness of the movable electrode and all are made of homogeneous material with mass density  .…”

“…Micro-tunable capacitors are miniature micro-sized structures that find various applications ranging from wireless systems to even high frequency-based circuits. They have attracted the attention of several researchers resulting into the publication of a significant research work [1][2][3][4][5] mainly devoted into considering these tiny structures in the design of numerous devices such as voltage control micro-oscillators [6,7], micro-filters [8][9][10], super-heterodyne micro-transceivers [11], etc… Tunability represents one of most important characteristics for micro-tunable capacitors, which is mainly be governed by the difference between their respective maximum and minimum capacitance values. The more the maximum capacitance is accomplished, the higher the tunability is.…”

Impact of Transduction Scaling Laws on Nanoelectromechanical Systems

“…A central MEMS functionality is the transduction between electromagnetic and mechanical degrees of freedom [3][4][5][6][7]. Electrostatic transducers have found applications ranging from experimental investigations of fundamental physics [8] over microrobotics and nanorobotics [9] to nanophotonics [10,11], and they were proposed as building blocks for adiabatic computing [12,13]. Moreover, electric transduction forms the basis of the optoelectromechanics research on, e.g., optical detection of radio waves [14], graphene-based superconductive devices [15], or manipulation of quantum states [16].…”