Sputtering yields of metal ion beams on polycrystalline films for energies below 1 keV were measured in situ using crystal microbalance techniques. Self-sputtering yields were determined for Au, Cu, Ag, Cr, and Al for energies from 10 to 500 eV. These yields were consistent with some previous noble-gas sputtering yields when only the difference in ionic mass was taken into account. Residual oxygen significantly lowered the self-sputtering yields of Al and Cr for all energies from 0 to 1 keV and the collection rate of oxygen was apparently greater for ions of about 10 eV. Sputtering yields of films by dissimilar metal ions were most strongly influenced by the type of metal in the beam, rather than by the target material, even for high ion energies.
The design, fabrication and characterization of a novel out-of-plane vertical comb-drive actuator based lamellar grating interferometer (LGI) is reported. The interferometer utilizes resonant mode vertical comb actuators, where comb fingers are simultaneously used for actuation and as a movable diffraction grating, making the device very compact. The Fourier transform of the zeroth order intensity pattern as a function of the optical path difference gives the spectrum of light. The main advantages offered by the proposed device are a long travel range (i.e. good spectral resolution), a large clear aperture (i.e. high light efficiency), and a very simple, robust and compact spectrometer structure. Peak-to-peak 106 µm out-of-plane deflection is observed in ambient pressure and at 28 V, corresponding to a theoretical spectral resolution of about 0.4 nm in the visible band and 3.6 nm at 1.5 µm. A simple CMOS compatible process based on bulk micromachining of a silicon-on-insulator wafer is used for the device fabrication.
Micro scanning mirrors are quite versatile MEMS devices for the deflection of a laser beam or a shaped beam from another light source. The most exciting application is certainly in laser-scanned displays. Laser television, home cinema and data projectors will display the most brilliant colors exceeding even plasma, OLED and CRT. Devices for front and rear projection will have advantages in size, weight and price. These advantages will be even more important in neareye virtual displays like head-mounted displays or viewfinders in digital cameras and potentially in UMTS handsets. Optical pattern generation by scanning a modulated beam over an area can be used also in a number of other applications: laser printers, direct writing of photo resist for printed circuit boards or laser marking and with higher laser power laser ablation or material processing. Scanning a continuous laser beam over a printed pattern and analyzing the scattered reflection is the principle of barcode reading in 1D and 2D. This principle works also for identification of signatures, coins, bank notes, vehicles and other objects. With a focused white-light or RGB beam even full color imaging with high resolution is possible from an amazingly small device. The form factor is also very interesting for the application in endoscopes. Further applications are light curtains for intrusion control and the generation of arbitrary line patterns for triangulation. Scanning a measurement beam extends point measurements to 1D or 2D scans. Automotive LIDAR (laser RADAR) or scanning confocal microscopy are just two examples. Last but not least there is the field of beam steering. E.g. for alloptical fiber switches or positioning of read-/write heads in optical storage devices. The variety of possible applications also brings a variety of specifications. This publication discusses various applications and their requirements
Special micro scanning mirrors have been designed for the investigation of torsional stress in micro-scale hinges made of crystalline silicon. The setup with precise logging of resonant frequency and deflection amplitude of the MEMS-scanners is described. First results on fatigue and fracture strenght are presented. Fracture of torsion beams with 6.6 µm x 30 µm cross-section occured at 2.0 GPa to 2.4 GPa. No sign of fatigue was observed in operation for 512 h at 1.4 GPa torsional stress in resonance at 2260.7 Hz oscillation frequency. Measured frequency variation was 0.06 % without any trend
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