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Facile, integrated and comprehensive software is needed for the design of processes, models and simulation, which are required for effective production of MEMS and microsystems. The characteristics of computer-aided design software now available from seven companies are reviewed. Three of the firms have roots in microelectronics, and three were formed specifically for MEMS design. Electronic, mechanical, thermal and fluidic mechanisms are commonly included. One company is especially strong in microfluidics. Two of the design suites permit computational coupling between a MEMS device and its package. High spatial- and temporal- resolution optical diagnostics are now producing detailed data that will challenge design and simulation software for MEMS and microsystems. Near and far term prospects for the CAD of MEMS and microsystems are projected.

This review provides a comprehensive survey of noise research in MEMS. Some background on noise and on MEMS is provided. We review noise production mechanisms, and highlight work on the theory and modeling of noise in MEMS. Then noise measurements in the specific types of MEMS are reviewed. Inertial MEMS (accelerometers and angular rate sensors), pressure and acoustic sensors, optical MEMS, RF MEMS, surface acoustic wave devices, flow sensors, and chemical and biological MEMS, as well as data storage devices and magnetic MEMS, are reviewed. We indicate opportunities for additional experimental and computational research on noise in MEMS.

The total laser energy (3–32 J), temporal history (40 ns full width at half maximum) and focal energy distribution (3×1013 W/cm2 peak, 1.5×1013 W/cm2 average) for λ=1.06 μm Nd:glass laser interactions with planar Al targets were measured. Laser-produced plasma emissions within the 1–3 keV x-ray range were recorded, with limited measurements in the 10–1000 eV range. Primary emphasis was given to obtaining the dependence of kilovolt x-ray emission on irradiance (varied by altering the energy on target or the lens-target spacing). A maximum efficiency for the conversion of incident laser energy to radiation above 1.5 keV was 0.25% into 2π sr. Integrated x-ray energy radiated over this range of photon energy was found to increase as the 3.2 power of laser energy at best focus. X-ray emission decreased when a prepulse preceded the main pulse by a controlled amount exceeding 0.2 μs but

A high vacuum soft x-ray source has been coupled to a large volume experimental chamber to provide a versatile facility for x-ray investigations in the energy range of 0.1 to 10 kev. The source chamber presently contains a modified Herike tube, but can employ any of a variety of source designs. The large experimental chamber is equipped with a kinematic mount to position a number of x-ray optical instruments. The source and experimental chambers are connected through a high vacuum valve/shutter, and are pumped separately with provision for a thin window to isolate one from the other, single and double crystal spectrometers have been used in the experimental chamber. A variable chord diffractometer/reflectometer using double crystal monnotiromatization has been designed, in addition, the facility has been used to expose photoresists in x-ray lithography tests.

Synchrotron radiation (SR) has several unique properties which cause it to be used for many purposes in science and technology. It is continuous spectrally, collimated spatially, short-pulsed yet continuously-operating temporally, as well as polarized( 1). Many applications of SR have already been demonstrated. These range from production of fine scale structures by lithography to numerous studies of materials. Determination of atomic structure by diffraction and other scattering experiments and by absorption spectroscopy (EXAFS), and emission spectroscopic studies of electronic structure have been given most attention(2). Only limited attention has been paid to determination of materials composition by x-ray fluorescence analysis (XRF) employing synchrotron radiation. Sparks et al.(3-5) have performed the most notable experiments, examining mica inclusions for the presence of primordial super heavy elements and irradiating two National Bureau of Standards Standard Reference Materials (SRM 1571, Orchard Leaves and SRM 1632, Coal) to measure the fluorescent x—ray intensity from the trace elements.

A systematic study of the minimum detection limits obtainable with synchrotron radiation continuum excitation has been made for thin samples of 10 elements distributed across the periodic table. Energy dispersion and wavelength dispersion measurements are included; the results show that both techniques achieve comparable values, ranging from 10/sup -3/ to 10/sup -1/ /sup +/g/cm/sup 2/, where line interference is absent. With the very small primary beam used for the energy dispersion measurements, this represents absolute detectability of 10/sup -12/ to 10 /sup -10/ g, in reasonable agreement with theoretical predictions. 4 figures, 5 tables.

X -ray spectra arising from the valence bands of solids are useful for basic studies of the electronic structure of most materials and for practical measurements of unknowns to obtain information on local atomic structure and material properties as well as chemical composition. Understanding the characteristics of valence band spectra is prerequisite to their fullest use. One-electron and many-body aspects of the x-ray emission process, and the effects of experimental conditions, must be understood and are reviewed. Interpretation of spectral features and determination of electronic structure are complementary parts of one procedure which is based on the use of bonding theory. The various band and bond theories which are finding use for spectral interpretation are briefly reviewed. Calculation of the electronic structure of aluminum metal and quartz, and interpretation of their x-ray spectra, are examples which illustrate basic work with valence band spectra.

Further investigations of the noise characteristics of MEMS accelerometers at different accelerations are presented. In the previously published work, the results show 1/f-type noise at low frequencies and white noise at high frequencies. The magnitude of the noise spectral density is acceleration dependent. In this paper, we probe further to investigate the spectral peaks which exist on all three accelerometers noise characteristics. Secondly, we perform analysis to find the 1/f exponents for all accelerometers noise characteristics. We also perform additional experiments to show the resonance effect of the noise characteristics.