Searching for optimum conditions in the laser writing of small ohmic contacts

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There is a need for chemically resistant coatings that protect the exposed surface of microfluidics components. Pinhole free films with low stress and a good uniformity on flat and inclined surfaces are required. In this study, amorphous silicon carbide (SiC) thin films have been deposited by RF magnetron sputtering on hat surfaces and into micromachined cavities of Si (100). The variation of RF power, deposition pressure and substrate bias voltage have been studied. Depending on the deposition conditions,

The anodic oxidn. of H2SO4 to H2S2O8 was investigated on B-doped synthetic diamond electrodes obtained by hot filament chem. vapor deposition. High current efficiency for H2S2O8 formation can be achieved in concd. H2SO4 (7.5 mol dm-3) and using high current densities (200 mA cm-2). The main side reaction is oxygen evolution. [on SciFinder (R)]

Intermetallic thin films of stoichiometric NiAl and Ni3Al have been deposited onto n-type silicon (100) and nickel (110) substrates using r.f.-magnetron co-sputtering. The morphology and crystal structure of the thin films have been studied by transmission electron microscopy from planar-view and cross-sectional samples. Chemical order has been assessed using nano-diffraction techniques. Superlattice reflections confirm a fully ordered structure in both intermetallics. These NiAl and Ni3Al thin films are na

Strontium Bismuth Titanate is a very promising material for high temperature piezoelectric applications, its elevated ferroelectric phase transition (530°C), linear piezoelectric properties under low field and relatively low room temperature conductivity (compared to others Bismuth Titanates) make it very attractive for precision sensors. However, under severe conditions (low frequency, high field, high temperature or low oxygen partial pressure) some of those advantages disappear. Piezoelectric response is

Excimer Laser Ablation is a micro-machining method which has undergone an important breakthrough in the last twenty years. In contrast with most literature studies, dealing with Static Ablation, this PhD work focuses on the study of Scanning Ablation of poly(ethylene terephthalate) (PET) at 193 nm, using relatively high fluences of about 1 J/cm2. Here, Static Ablation means that the substrate is fixed with respect to the laser beam. In this way, the size of the machined area per set of pulses does not excee

New experimental study of heavy ion and proton induced SEU at reduced voltage (i.e. reduced critical charge) reveals interesting results. It is shown that the heavy ion cross section and microprobe mapping scale like the threshold LET and the parameter, which is almost invariant under bias changes, is the effective charge collection depth. For studying proton induced SEU and surface-barrier-detector spectra we use protons with energies from 5.6 to 300MeV. The results are analyzed in view of the processes in

For future divertor studies on TCV measurements of electron temperature and density and their spatial gradients along open flux surfaces will be of major interest. A Thomson scattering system is proposed for this purpose, which takes advantage of the good access via horizontal ports on three vertical levels. The modular design of the existing Thomson scattering diagnostic on TCV offers the possibility to modify it for simultaneous measurements in the main plasma and in the divertor region using the same las

Several bottom electrode systems for ferroelectric thin film deposition onto reactive substrates or reactive metal films have been investigated with respect to chemical barrier properties and contact resistivity. Such electrode systems should not deteriorate by oxidation, and should prevent oxygen diffusion into the underlying base metal. First, the protective performance of Pt, Ru, RuO2/Ru, and Cr has been evaluated on reactive substances such as W, Zr, Mo, and TiN; On most materials, a reactive and passiv

We report on studies of extended defects in electron-beam-pumped Zn1-xCdxSe/ZnSe blue and blue-green laser structures. To establish a direct correlation between the local luminescence properties and the presence of structural defects, the same thin foil samples were sequentially examined by transmission electron microscopy (TEM) and cathodoluminescence (CL) microscopy. The majority of the non-radiative defects were found to have one or more threading dislocations in their vicinity. Stacking faults, as a rul

Photoluminescence intensity and emission wavelength of InAsP/InGaAsP and InGaAs/InGaAsP multi-quantum well (MQW) laser structures grown by chemical beam epitaxy (CBE) at 460 degrees C and V/III ratio of 2 are considerably affected by annealing at temperatures 600-650 degrees C which prevents lasing of these structures fused on GaAs substrates. It is shown that the degradation of luminescence characteristics can be decreased by increasing the growth temperature to 480 degrees C and V/III ratio to 4. InAsP/In

Degradation defects induced by electron-beam bombardment in Zn1-xCdxSe/ZnSe (001) graded-index separate-confinement blue-green laser structures have been characterized by transmission electron microscopy. Most defects appear as tree-like arrangements of small extrinsic and intrinsic dislocation loops opening in +/-[100] or +/-[010] directions and are located within the quantum well or at its boundaries. The Burgers vectors of the loops were identified as b = 1/2[01(1) over bar] and b = 1/2[10(1) over bar] f

We have recently shown that in II-VI/III-V heterojunctions and related devices fabricated by molecular beam epitaxy, the II/VI flux ratio employed during the early stages of II-VI growth can be used to control the local interface composition and the band alignment. Here we demonstrate that the local interface composition in pseudomorphic, strained ZnSe/GaAs(001) heterostructures as well as lattice-matched ZnSe/In0.04Ga0.96As(001) heterostructures also have a dramatic effect on the nucleation of native stack

Searching for optimum conditions in the laser writing of small ohmic contacts

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Sputtered silicon carbide thin films as protective coating for MEMS applications

Preparation of peroxodisulfuric acid using boron-doped diamond thin film electrodes

Microstructure and growth modes of stoichiometric NiAl and Ni3Al thin films deposited by r.f.-magnetron sputtering

Conductivity, dielectric and piezoelectric properties of SrBi4Ti4O15

Scanning excimer laser ablation of poly(ethylene terephthalate) (PET) and its application to rapid prototyping of channels for microfluidics

Scaling of SEU mapping and cross section, and proton induced SEU at reduced supply voltage

A Thomson scattering diagnostic for measurements in the divertor region of TCV

Conducting barriers for direct contact of PZT thin films on reactive substrates

Transmission electron microscopy and cathodoluminescence studies of extended defects in electron-beam-pumped Zn1-xCdxSe/ZnSe blue-green lasers

Thermal Stability of InP-Based Structures for Wafer Fused Laser Diodes

Degradation defects in electron-beam-pumped Zn1-xCdxSe/ZnSe graded-index separate-confinement heterostructure (GRINSCH) blue and blue-green lasers

Local interface composition and extended defect density in ZnSe/GaAs(001) and ZnSe/In0.04Ga0.96As(001) heterojunctions