H. Sandmaier

A micro membrane pump with electrostatic actuation

A bulk micromachined membrane pump with outer dimensions of 7 mm*7 mm*2 mm and electrostatic actuation is presented. The micropump consists of four silicon chips, which form two passive check valves, a pump membrane and a counterelectrode for electrostatic actuation. Direct electrostatic forces are used for the deflection of the pump membrane, which has an area of 4 mm*4 mm and a thickness of 25 mu m. The liquid to be pumped is not subjected to any electrical field. The separation between the movable membrane and the electrically isolated stator is 4 mu m.<<ETX>>

Thermal flow sensor for liquids and gases based on combinations of two principles

A new type of a flow sensor is presented which is based on a thermal principle. The combination of two detecting methods results both in a considerable increase in measuring range (0.1 to 150 mm/s) and in a shorter reaction time of less than 2 ms. Furthermore, the sensor is relatively insensitive to pollution. Devices were manufactured and successfully tested for liquids and gases.

A micromachined electrohydrodynamic (EHD) pump

Abstract A new micromachined electrohydrodynamic (EHD) injection pump is presented. The pump mainly consists of two facing grids, which are micromachined from s

Decoupled microgyros and the design principle DAVED

This paper reports the surface micromachined gyroscopes realized by HSG-IMIT according to the patented decoupling principle DAVED (DECOUPLED ANGULAR VELOCITY DETECTOR). The DAVED prototypes show a rms noise below 0.05/sup o///sub s/ and a bias stability of /spl plusmn/2.5 /sup o///sub s/ over the temperature range and thus meet the target specification comparable to ESP requirements. Further, a novel and advanced concept is presented which can be viewed as a doubly decoupling scheme. The goal of decoupling is to reduce the so-called quadrature signal and thus improve the sensor performance, especially, the temperature sensitivity. This advancement will be necessary to meet the demands of future applications, like, ADASs (Advanced Driver Assistance System) or partially replace fiber optic gyroscopes, for example, within autonomous guided vehicles.

An electrohydrodynamic micropump

A micromachined electrohydrodynamic (EHD) injection pump is presented. The pump consists mainly of two opposed grids, which are micromachined from single crystal silicon and bonded together anodically. Pumping and static pressure generation is achieved with different polar fluids such as ethanol, propanol, or acetone, but most organic solvents can be pumped. With ethanol a maximum static pressure of 2.5 kPa (32 cm pumping head) and a pumping rate of 14 ml/min at a pressure of 420 Pa are achieved. For the realized pump the grid area measures 3 mm*3 mm and the grid distance 350 mu m. Pumping starts at DC voltages as low as 40 V, whereas 700 V are needed for maximum throughput. Pumping is also observed with an AC driving voltage. To increase pressure several of the devices can be stacked. The maximum flow rate and pressure head can be varied in a wide range by adjusting the dimensions of the pump. By further reducing the grid distance the driving voltages can be reduced.<<ETX>>

Micromachined inclinometer with high sensitivity and very good stability

An investigation on thermal inclinometers working with free convective flow is presented. This type of sensors shows high sensitivity and good baseline stability. Thermal time constants of 110 ms are achieved. Due to the free convection working principle, the housing has a direct influence on the sensor function. Experiments with different kinds of sensor caps are presented, the system composition and the sensor housing especially the dependence on cap volume and the enclosed gas are discussed.

Electrohydrodynamic pumping and flow measurement

A micromachined electrohydrodynamic (EHD) injection pump with improved characteristics and a novel method for flow measurement with the same structure are presented. Based on the structure of the EHD injection pump, an improved design with grid distances in the range between 10 mu m and 60 mu m was achieved, yielding a reduction in the required driving voltage. Grid areas of 2.5*2.5 mm/sup 2/ and 1*1 mm/sup 2/ were accomplished. The outer dimensions of the smallest pumps are 3*3*1.0 mm/sup 3/. One of the grids is etched back from the frontside and mounted upside down on the lower grid in order to reduce the grid distance. The two grids are bounded together by anodic bonding. The pump is mounted in a ceramic housing with two fluid ports. Based on this structure, a novel method for the measurement of fluid flow and velocity was developed. This technique is well suited for small flow rates below 100 mL/min down to some mu L/min. Volumetric flow rates down to 8 mu L/min were measured with a 2.5*2.5 mm/sup 2/ grid area.<<ETX>>

New designs of micromachined vibrating rate gyroscopes with decoupled oscillation modes

Abstract This paper reports on new vibrating comb-drive rate gyroscope designs featuring decoupling of the actuation and the detection mode. Analytical calculations as well as FEM and system simulations are carried out. It is investigated how to overcome the main drawbacks of these sensors, which are especially the frequency mismatch of the two oscillation modes, the insufficient bandwidth and the effects of levitation. Concepts and simulations of electrostatically controlling both the resonance frequency and the bandwidth are presented. Within these concepts no mechanical balancing of the device is required and thus calibration costs are reduced. Simulations of a new quasi-rotating rate gyroscope show that a resolution of 0.1 ° s −1 is possible at a bandwidth of 50 Hz with 6 mm 2 sensor area only, and that the effects of levitation are actually compensated. The design has been fabricated within the Bosch Foundry process. First measurements of the angular rate show a resolution of 0.5 ° s −1 in a 50 Hz bandwidth.

Absorbing layers for thermal infrared detectors

Abstract Infrared absorbing layers are used to transform radiation into heat. They must combine high absorption with low film thickness. Three methods for their deposition have been investigated: thin metallic films; platinum black deposited by a galvanic process; highly porous metals deposited by evaporation in nitrogen.

Methods for the fabrication of convex corners in anisotropic etching of (100) silicon in aqueous KOH

Abstract In this paper, a method for the fabrication of convex corners in (100) silicon in KOH etchant is presented. Based on the identification of the planes occurring at convex corners during etching in this solution and the determination of the etching rate ratio of these planes in relation to the {100} planes, special structures suited for the compensation of the under-cutting in the case of very narrow contours have been developed. With the help of these structures it is feasible to realize bent V-grooves or structures with a very low ratio between lateral expansion and etching depth, e.g., a discrete truncated pyramid, formed by {111} planes or {411} planes, with minimum dimensions on the wafer surface.