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This paper presents the design, modeling, and fabrication of a planar three-degrees-of-freedom parallel kinematic manipulator, fabricated with a simple two-mask process in conventional highly doped single-crystalline silicon (SCS) wafers \langle 100\rangle. The manipulator's purpose is to provide accurate and stable positioning of a small sample (10 \times 20 \times 0.2\ \mu\m^3), e.g., within a transmission electron microscope. The manipulator design is based on the principles of exact constraint design, resulting in a high actuation-compliance combined with a relatively high suspension stiffness. A modal analysis shows that the fourth vibration mode frequency is at least a factor 11 higher than the first three actuation-related mode frequencies. The comb-drive actuators are modeled in combination with the shuttle suspensions gaining insight into the side and rotational pull-in stability conditions. The two-mask fabrication process enables high-aspect-ratio structures, combined with electrical trench insulation. Trench insulation allows structures in conventional wafers to be mechanically connected while being electrically insulated from each other. Device characterization shows high linearity of displacement wrt voltage squared over \pm10 \mu\m stroke in the x- and y-directions and \pm 2^\circ rotation at a maximum of 50 V driving voltage. Out-of-plane displacement crosstalk due to in-plane actuation in resonance is measured to be less than 20 pm. The hysteresis in SCS, measured using white light interferometry, is shown to be extremely small. \hfill[2009-0254] [ABSTRACT FROM PUBLISHER]

A submicron thick and defect-free palladium-silver (Pd-Ag) alloy membrane is fabricated on a supporting microsieve by using microfabrication techniques. The microfabrication process also creates a robust wafer-scale membrane module, which can easily be inserted into a membrane holder to have gas-tight connections to the outer world. The microfabricated membrane demonstrated high separation fluxes of up to 4 mol 112/rn2 . s with a minimal selectivity of 1500 for hydrogen over helium (H2 /He) at 450 °C and 83 kPa 112 retentate pressure. The present membrane has great potential for hydrogen purification and in applications like dehydrogenation chemistry. In addition, the presented technology can be used to fabricate other kinds of ultrathin but strong and defect-free membranes to set up new applications. [1235] [ABSTRACT FROM AUTHOR]

In this paper, a process for the microfabrication of a wafer-scale palladium—silver alloy membrane (Pd-Ag) is presented. Pd-Ag alloy films containing 23 wt% Ag were prepared by co-sputtering from pure Pd and Ag targets. The films were deposited on the unetched side of a 〈110〉-oriented silicon wafer in which deep grooves were etched in a concentrated KOH solution, leaving silicon membranes with a thickness of ca. 50 µm. After alloy deposition, the silicon membranes were removed by etching, leaving Pd-Ag membranes. Anodic bonding of thick glass plates (containing powder blasted flow channels) to both sides of the silicon substrate was used to package the membranes and create a robust module. The hydrogen permeability of the Pd-Ag membranes was determined to be typically 0.5 mol H[sub 2]/m² · s with a minimal selectivity of 550 for H[sub 2] with respect to He. The mechanical strength of the membrane was found to be adequate, pressures of up to 4 bars at room temperature did not break the membrane. The results indicate that the membranes are suitable for application in hydrogen purification or in dehydrogenation reactors. The presented fabrication method allows the development of a module for industrial applications that consists of a stack of a large number of glass/membrane plates. [ABSTRACT FROM AUTHOR]

Presents guidelines for etching silicon microelectromechanical systems structures using fluorine high-density plasmas at cryogenic temperatures. Deposition of the silicon layer; Kinetic energy of ions in the plasma; Selectivity of silicon etching; Crystallographic preference etching of silicon.

Focuses on the development of a micromachined flow cell consisting of a flow channel integrated with micropipettes. Significance of silicon micromachining on flow cell; Properties of DNA molecules.