Evaluation and simulation of NEMS cantilever relays

Abstract

Electrostatically-actuated NEMS cantilevers were fabricated for testing as a potential replacement for nanoscale circuit components in power-critical applications such as spacecraft. These cantilevers are manipulated and switched in a horizontal plane by applying a voltage to lateral electrodes. A variety of poly-Si cantilevers were fabricated at SEMATECH with a range of beam lengths (from 2 pm to 14 pm) and electrode gap spacing (from 110 nm to 140 nm). After fabrication, the cantilevers were tested at SEMATECH to determine the voltage required to generate sufficient electrostatic force between the driving electrode and beam to bring the beam into contact with the collector. This pull-in voltage was measured as a function of device dimensions. To simulate the device operation, a model was created in COMSOL, a NEMS simulation software package. Simulations of pull-in voltage and pull-in time were compared to the data to both validate the model and estimate the frequency response of the devices. Variations of model device parameters such as beam thickness, height, gap size, and Young’s modulus were used to define a design space based on power requirements. SEM images were obtained at Texas State University-San Marcos to study failure mechanisms of various tested devices. This work is systematically evaluating the effects of device dimensions on the operational characteristics and failure mechanisms of lateral nanoscale cantilevers for low power applications.