Quasi-monolithic planar load cells using built-in resonant strain gauges

Two load cell designs are presented using resonant strain gauges providing a frequency output. One design is based on a four-point beam deflection jig. It offers high sensitivity, but suffers from robustness and impractical geometries for a broad force range. A modified planar design (typical dimensions 1-10 mm) removes these drawbacks and in addition features built-in force reduction, overhead protection and compensation of common mode effects. Load ranges vary from high (1 500 N) to very low (0.03 N), with theoretically achievable resolutions as high a 1 part in 107

Design challenges for stepper motor actuated microvalve based on fine and micro-machining

We present a normally open stepper motor actuated microvalve based on micro and fine-machining technique. In this paper, first we have described how the larger controllable flow range can be achieved with simple micromachining techniques and secondly we have presented the results which show how the performance of the microvalve can be improved by using combination of different metal screws for mechanical transmission of power to deflect the membrane to control the flow of gas

Fiber-top cantilevers: a new sensor on the tip of a fiber

Micromachined cantilevers are the most elementary example of miniaturized sensors. A free-standing rectangular beam can often detect changes in the chemical, biological and physical properties of the surroundings with sensitivity comparable to much more complicated devices. It is therefore not surprising that this simple design is still at the heart of several scientific instruments

Contact nucleation: in situ and ex situ observations of surface damaging

To investigate the damaging done to a crystal surface potassium dihydrogen phosphate, KDP and potassium hydrogen phthalate, KAP) due to a crystal-rod contact, both ex situ and in situ experiments were performed and the impact sites studied either using an interference contrast microscope or a scanning electron microscope. An ex situ contact (performed in air) causes subsurface cracks and the breakage of small fragments (KDP) or the removal of thin plates (KAP) from the surface. In the former case the fragments have thicknesses roughly corresponding to the height of macrosteps present on the surface. Contacts during growth on KAP produced secondary nuclei; the crystal size distribution of these nuclei displays a log-normal behaviour

Seedless electroplating on patterned silicon

Nickel thin films have been electrodeposited without the use of an additional\ud seed layer, on highly doped silicon wafers. These substrates conduct\ud sufficiently well to allow deposition using a peripherical electrical contact on\ud the wafer. Films 2 μm thick have been deposited using a nickel sulfamate\ud bath on both n+- and p+-type silicon wafers, where a series of trenches with\ud different widths had been previously etched by plasma etching. A new,\ud reliable and simple procedure based on the removal of the native oxide layer\ud is presented which allows uniform plating of patterned substrates

Fabrication and capillary filling of sub-10nm nanochannels

Keywords: Nanochannels, capillarity, viscosit

Wafer scale nano-membranes supported on a silicon microsieve

A new micromachining method to fabricate wafer scale, atomically smooth nano-membranes is described. The delicate membrane is supported on a robust silicon microsieve fabricated by plasma etching. The supporting sieve is micromachined independently of the nano-membrane, which is later fusion bonded to it. The transferred thin-film membrane can be dense, porous or perforated according to the application desired. One of the main application areas for such membranes is in fluidics, where the small thickness and high strength of the supported nano-membranes is a big advantage. The novel method described enables to easily up-scale and interface micro or nano-membranes to the macro-worl