Stability of symmetrical comb-drive actuator

18th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications 4–7 December 2018, Daytona Beach, Florida, USAInternational audienceThis paper reports the study, design, and simulation of a symmetrical comb-drive actuator. The approach for definition of the potential energy of the system is proposed. The electrical parameters of the comb-drive actuator are defined in COMSOL Multiphysics® software. Depending on an actuation voltage and an initial design it can form system with one, two, and three stable states. We show that the equilibrium at x = 0 is more stable for the comb-drive actuator with positive overlap than for device with the gap of the same value. The proposed approach will be used for design of the symmetrical actuator, which forms the output of the recently proposed contactless four-terminal MEMS element for capacitive adiabatic logic based on silicon MEMS technology

Contact-Free MEMS Devices for Reliable and Low-Power Logic Operations

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MEMS Four-Terminal Variable Capacitor for low power Capacitive Adiabatic Logic with High Logic State Differentiation

International audienceThis paper presents a novel four-terminal variable capacitor (FTVC) dedicated to the recent concept of low power capacitive adiabatic logic (CAL). This FTVC is based on silicon nano/micro technologies and is intended to achieve adiabatic logic functions with a better efficiency that by using field effect transistor (FET). The proposed FTVC consists of two capacitors mechanically coupled and electrically isolated, where a comb-drive input capacitor controls a gap-closing capacitor at the output. To fully implement the adiabatic combinational logic, we propose two types of variable capacitors: a positive variable capacitor (PVC) where the output capacitance value increases with the input voltage, and a negative variable capacitance (NVC) where the output capacitance value decreases when the input voltage increases. A compact and accurate electromechanical model has been developed. The electromechanical simulations demonstrate the ability of the proposed FTVC devices for CAL, with improved features such as high logic states differentiation larger than 50% of the full-scale input signal and cascability of both buffers and inverters. Based on the presented analysis, 89% of the total injected energy in the device can be recovered, the remaining energy being dissipated through mechanical damping. During one cycle of operation, a buffer gate of 10x2.5 µm 2 dissipates only 0.9 fJ