Oxynitride films formed by low energy NO+ implantation into silicon

Oxynitride (SiOxNy) insulators have been obtained by low-energy nitric oxide ion (NO+) implantation in Si substrates prior to thermal oxidation. Characterization by Fourier transform infrared (FTIR) and secondary ion mass spectrometry (SIMS) analyses reveal the presence of Si-O, Si-N, and Si-N-O bonds in the high quality 37 nm silicon oxynitride films. The dielectric constant=5.5, effective charge density=7X10(10) cm(-2) and breakdown E-fields of 3 MV/cm were determined by capacitance-voltage (C-V) and current-voltage (I-V) measurements, respectively, indicating that the SiOxNy films formed are suitable gate insulators for metal-oxide-semiconductor (MOS) devices. (C) 1996 American Institute of Physics.69152214221

Study of conditions for anisotropic plasma etching of tungsten and tungsten nitride using SF6/Ar gas mixtures

Results of the study of reactive ion etching of tungsten, tungsten nitride, and silicon in SF6/Ar gas mixtures are presented. For plasma diagnostics, optical emission spectroscopy (actinometry) was used. Using the actinometry technique, it was possible to show that etching mechanisms were different for Si-F and W-F chemistries. Anisotropic etching of tungsten/tungsten nitride using conventional reactive ion etcher has been obtained, and conditions of achieving anisotropic etching have been analyzed. A correlation is found between anisotropy of tungsten etching and the ratio of Si/W etch rates. Mechanisms of fluorine redistribution between the bottom/sidewall surfaces due to surface diffusion and/or reflection are proposed as possible reasons for the observed correlation.1493G179G18

Efficacy of ECR-CVD silicon nitride passivation in InGaP/GaAs HBTs

High quality passivation silicon nitride films have been obtained requiring no surface pretreatment and being fully compatible with monolithic microwave integrated circuits. The nitride film is deposited by electron cyclotron resonance-chemical vapor deposition directly over GaAs-n substrate and over InGaP/GaAs heterojunction structures, which are used for heterojunction bipolar transistors (HBTs). Metal/ nitride/ GaAs-n capacitors were fabricated for all the samples. Effective charge densities of 3 X 10(11) cm(-2) and leakage current densities of 1 mu A/cm(2) were determined. Plasma analysis showed a reduced formation of molecules such as NH in the gas phase at low pressures, allowing the deposition of higher quality films. The process was used for InGaP/GaAs HBT fabrication with excellent results, such as higher current gain of passivated device comparing to unpassivated HBTs. (c) 2006 American Vacuum Society.2441762176

Benznidazole biotransformation and multiple targets in <i>Trypanosoma</i> cruzi revealed by metabolomics

&lt;b&gt;Background&lt;/b&gt;&lt;p&gt;&lt;/p&gt; The first line treatment for Chagas disease, a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, involves administration of benznidazole (Bzn). Bzn is a 2-nitroimidazole pro-drug which requires nitroreduction to become active, although its mode of action is not fully understood. In the present work we used a non-targeted MS-based metabolomics approach to study the metabolic response of T. cruzi to Bzn.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methodology/Principal findings&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Parasites treated with Bzn were minimally altered compared to untreated trypanosomes, although the redox active thiols trypanothione, homotrypanothione and cysteine were significantly diminished in abundance post-treatment. In addition, multiple Bzn-derived metabolites were detected after treatment. These metabolites included reduction products, fragments and covalent adducts of reduced Bzn linked to each of the major low molecular weight thiols: trypanothione, glutathione, γ-glutamylcysteine, glutathionylspermidine, cysteine and ovothiol A. Bzn products known to be generated in vitro by the unusual trypanosomal nitroreductase, TcNTRI, were found within the parasites, but low molecular weight adducts of glyoxal, a proposed toxic end-product of NTRI Bzn metabolism, were not detected.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions/significance&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Our data is indicative of a major role of the thiol binding capacity of Bzn reduction products in the mechanism of Bzn toxicity against T. cruzi

Deposition of sacrificial silicon oxide layers by electron cyclotron resonance plasma

Electron cyclotron resonance plasmas with SiH4/O-2/Ar mixtures were used for deposition of thin films of silicon oxide, to be employed as sacrificial layers in microelectromechanical system (MEMS) fabrication. The grown films were characterized by Fourier transform infrared and ellipsometry. Optical emission spectroscopy and Langmuir probe were used for plasma characterization. It has been shown that OH molecules generated in the plasma play an important role in formation of films suitable as sacrificial layers for MEMS fabrication. Extremely high etch rates of grown oxide films (up to 10 mu m/min) were obtained, allowing fabrication of high quality poly-Si suspended structures. (c) 2007 American Vacuum Society.2541166117

Data analysis workflow for the detection of canine vector-borne pathogens using 16 S rRNA Next-Generation Sequencing

Background Vector-borne diseases (VBDs) impact both human and veterinary medicine and pose special public health challenges. The main bacterial vector-borne pathogens (VBPs) of importance in veterinary medicine include Anaplasma spp., Bartonella spp., Ehrlichia spp., and Spotted Fever Group Rickettsia. Taxon-targeted PCR assays are the current gold standard for VBP diagnostics but limitations on the detection of genetically diverse organisms support a novel approach for broader detection of VBPs. We present a methodology for genetic characterization of VBPs using Next-Generation Sequencing (NGS) and computational approaches. A major advantage of NGS is the ability to detect multiple organisms present in the same clinical sample in an unsupervised (i.e. non-targeted) and semi-quantitative way. The Standard Operating Procedure (SOP) presented here combines industry-standard microbiome analysis tools with our ad-hoc bioinformatic scripts to form a complete analysis pipeline accessible to veterinary scientists and freely available for download and use at https://github.com/eltonjrv/microbiome.westernu/tree/SOP. Results We tested and validated our SOP by mimicking single, double, and triple infections in genomic canine DNA using serial dilutions of plasmids containing the entire 16 S rRNA gene sequence of (A) phagocytophilum, (B) v. berkhoffii, and E. canis. NGS with broad-range 16 S rRNA primers followed by our bioinformatics SOP was capable of detecting these pathogens in biological replicates of different dilutions. These results illustrate the ability of NGS to detect and genetically characterize multi-infections with different amounts of pathogens in a single sample. Conclusions Bloodborne microbiomics & metagenomics approaches may help expand the molecular diagnostic toolbox in veterinary and human medicine. In this paper, we present both in vitro and in silico detailed protocols that can be combined into a single workflow that may provide a significant improvement in VBP diagnostics and also facilitate future applications of microbiome research in veterinary medicine