An analysis of the dynamic characteristics of pull-in for parallel-plate and torsional electrostatic actuators is presented. Traditionally, the analysis for pull-in has been done using quasi-static assumptions. However, it was recently shown experimentally that a step input can cause a decrease in the voltage required for pull-in to occur. We propose an energy-based solution for the step voltage required for pull-in that predicts the experimentally observed decrease in the pull-in voltage. We then use similar energy techniques to explore pull-in due to an actuation signal that is modulated depending on the sign of the velocity of the plate (i.e., modulated at the instantaneous mechanical resonant frequency). For this type of actuation signal, significant reductions in the pull-in voltage can theoretically be achieved without changing the stiffness of the structure. This analysis is significant to both parallel-plate and torsional electrostatic microelectromechanical systems (MEMS) switching structures where a reduced operating voltage without sacrificing stiffness is desired, as well as electrostatic MEMS oscillators where pull-in due to dynamic effects needs to be avoided.

Dynamic pull-in of parallel plate and torsional electrostatic MEMS actuators.

Tri-state nanoelectromechanical (NEM) memory switches are proposed for the implementation of high-impedance state 0 in addition to low-impedance states 1 and 2 for the improvement of conventional complementary metal-oxide-semiconductor-NEM (CMOS-NEM) reconfigurable logic (RL) operations. Although it is well known that the high impedance state of routing switches is essential to prevent the unnecessary data throughput of RL circuits, previously proposed NEM memory switches have only implemented binary states: states 1 and 2. On the contrary, our proposed NEM memory switches can have tri-states, which are achieved by modifying their operation methods and design guidelines.

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Tri-State Nanoelectromechanical Memory Switches for the Implementation of a High-Impedance State

A tristate-nanoelectromechanical-switch-based ternary content-addressable memory (NEMTCAM) is proposed for the first time. In the proposed unit NEMTCAM cell, a single nanoelectromechanical (NEM) memory switch replaces two static random access memory cells. Due to the monolithic 3-D (M3D) integration and nonvolatile property of NEM memory switches, the proposed NEMTCAM achieves an 86.3% smaller area, 75.0% lower dynamic power consumption, and a 76.6% higher search speed than conventional ternary content-addressable memory (TCAM) in addition to a negligible static leakage current.

Nanoelectromechanical-Switch-Based Ternary Content-Addressable Memory (NEMTCAM)

This paper proposes a novel nanoelectromechanical-switch-based binary content-addressable memory (NEMBCAM) for the first time. A nanoelectromechanical (NEM) memory switch serves as both a nonvolatile memory and a switchable current path in an NEMBCAM unit cell. Owing to monolithic three-dimensional integration, NEMBCAM achieves a smaller unit cell area in comparison with conventional complementary metal–oxide–semiconductor-only binary content-addressable memory. Small unit cell area results in reduced match line (ML) capacitance, which lowers search energy consumption. Furthermore, a shorter search delay is achieved owing to the near-perfect on/off characteristic of the NEM memory switch.

/pdf/nanoelectromechanical-switch-based-binary-content-5cwzb8w4sq.pdf

Nanoelectromechanical-Switch-Based Binary Content-Addressable Memory (NEMBCAM)

Selection Line Optimization of Nanoelectromechanical (NEM) Memory Switches for Stress Relief

A dynamic slingshot pull-in operation is presented by using the influence of inertia and damping on the nanoelectromechanical (NEM) memory switch operation. To confirm the validity of the proposed idea, a finite element analysis (FEA) simulation, that reflects the actual cantilever beam structure, is performed, and an analytical one-dimensional (1D), the parallel plate model is tested. According to the analytical and FEA data, the dynamic slingshot pull-in voltage can be achieved ~0.78 times and ~0.73 times lower than conventional pull-in voltage under near-vacuum conditions, respectively. It is also shown that the proposed dynamic slingshot operation is more effective for lowering operation voltage ( $V_{\mathrm {DD}}$ ) and boosting the chip density of complementary-metal-oxide-semiconductor (CMOS)- NEM hybrid reconfigurable logic (RL) circuits than the static slingshot operation.

Min Hee Kang

Papers

Selection Line Optimization of Nanoelectromechanical (NEM) Memory Switches for Stress Relief

Dynamic Slingshot Operation for Low-Operation- Voltage Nanoelectromechanical (NEM) Memory Switches