We have used double clamped beams to implement a mechanical memory. Compressive stress is generated by resistive heating of the beams and beyond the buckling limit the bistable regime is accessed. Bits are written by applying lateral electrostatic forces. The state of the beam is read out by measuring the capacitance between beam and electrodes. Two ways to implement a mechanical memory are discussed: compensation of initial beam imperfections and snap through of the postbuckled beam. Although s...

In recent years, relatively simple MEMS fabrications have helped accelerate our knowledge of the microbial cell. Current progress and challenges in the application of lab-on-a-chip devices to the viable microbe are reviewed. Furthermore, the degree to which microbiologists are becoming the engineers and are tailoring microbial cells and protocells as potential components for bioMEMS devices is highlighted. We conclude this is a highly productive time for microbiologists and microengineers to unite their shared interest in the micron scale world.

The acceleration sensors are getting popular in air-bag, GPS navigator, HDD, game console and mobile phone. The latest acceleration sensors adopt the MEMS (MicroElectroMechanical System) technology, offers high reliability and sensitivity in a small size. I am involved in an impact triggered automatic camera with a MEMS sensor. The product is simple. It is an event recorder as a black box for after market.

This letter¹ presents a method to measure the Young?s moduli of individual thin-film layers in a commercial integrated circuit (IC) foundry process. The method is based on measuring the resonance frequency of an array of micromachined cantilevers and using the presented optimization analysis to determine the elastic modulus of each layer. Arrays of cantilever test structures were fabricated in a commercial CMOS IC process and were released using XeF₂ as a postprocessing etch. A piezoelectric transducer placed under the test chip was used to excite the cantilevers to resonance, and the resonance frequency was measured using a laser Doppler vibrometer. It is reported that excellent agreement for values of Young?s modulus is observed for cantilevers between 200 and 400 mum in length, with average standard deviation being 4.07 GPa.

This paper, which is mostly tutorial in nature, deals with the design of CMOS microelectromechanical systems MEMS using standard microelectronic computer-aided design tools. The proposed case study is an on-chip spectrum analyzer with an electronic mixer and a mechanical filter. Based on both analytical modeling and characterization, the filter is described using an analog hardware description language. System level simulations are then performed using a recently released simulation tool that offer new possibilities regarding the analysis of multidomain, multifrequency designs. Presented results include periodic steady state determination, small-signal analysis and noise investigation. The simulations demonstrate the ability of the proposed system to identify the harmonics of a 50-Hz square-wave signal, owing to the selectivity of the mechanical filter.