On-chip nanoporous gold (NPG) fabrication has been successfully developed by Au-Sn alloys electrodeposition and dealloying process, to use its compressible body and nanostructured surface for micro electro mechanical systems (MEMS) applications. Anodically-bondable low temperature cofired ceramic (LTCC) substrates are proposed to provide electrical connective packaging by using novel nano-structured gold. The porous structure offers sponge-like functions which forms electrical contacts as well during anodic bonding. Nanoporous gold with porosity in nanoscale indicates a highly reactive surface which makes it possible to be a promising candidate for bonding process to reduce the bonding temperature. Low temperature bonding has been achieved by using nanoporous gold. These encouraging results imply good possibilities of nanoporous gold for MEMS packaging applications.

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The dynamic behavior of microelectromechanical systems (MEMS) sensors is very important to their response performance. In particular, the damping effect of the fluid resistance in a minute gap determines a sensor's response characteristics. Quartz tilt sensors fabricated by anisotropic wet etching have nonparallel comb electrodes. The fluid damping phenomenon in the nonparallel electrode is generally evaluated by numerical analysis (the finite element method). However, many numerical analysis results are required to elucidate the qualitative features of physical phenomena. We evaluated the fluid damping of nonparallel electrodes analytically and experimentally verified the effectiveness of the analytical solution. This paper describes the theoretical damping analysis of nonparallel electrodes and the experimentally investigated damping characteristics of a quartz tilt sensor, and then discusses the analytical and experimental results.

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The sensing principle of fiber-optic electric current sensors is based on the Faraday effect. Electric current flowing in a conductor induces a magnetic field, which rotates the plane of polarization of the light traveling in a sensing path encircling the conductor. There are two types of sensing techniques. One is a polarimetric-type measuring the polarization direction change, the other is an interferometric-type detecting the phase difference between counter-propagating circular-polarization lights through a sensing fiber loop. An all-fiber Sagnac interferometer-type fiber-optic electric current sensor was developed and successfully tested. The advantages of this sensor are its performance and light structure, ease of handling, and robustness to an external magnetic field caused by an adjacent electric current. The basic characteristics of the fiber-optic current sensor were compared with those of conventional Hall effect current sensors. The fiber-optic current sensor showed sufficient response less than 1 ms and resolution of 10 A for practical application in a short circuit test, and its strong robustness to an external magnetic field was shown experimentally. The sensor was tested in a possible future measurement and protection applications in railway power systems. The field test configurations and results are described.

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In order to develop compact, low-cost vacuum sensors, a thermally-conductive type MEMS sensor fabricated using a simple SOI-MEMS technology was studied. The sensor consists of cantilever-type heater and two temperature detectors which are faced to the tip of the heater. The prototype was fabricated and evaluated, resulting in a wide measurement range.

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The sheet resistance of a silicon wafer has conventionally been measured with the four-point probe technique and/or high frequency sinusoidal magnetic excitation with a Robinson marginal oscillator as an excitation current supply. The authors propose a novel contactless method of measuring sheet resistance that utilizes a pulse voltage to generate an eddy current in the sheet under test. The novel method can measure the sheet resistance under 5 mΩ/sq., that is the smallest value the conventional contactless method can measure.

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In this paper, we report a MEMS Fabry-Perot tunable filter with Dual Electrodes Electrostatic Actuator (DEEA) which improves the resolution of the mirror gap positioning. This device improved positioning resolution by changing two actuators of the DEEA and achieved the higher resolution less than 0.1nm by using 12bit driver circuit.

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