Composants Passifs Intégrés en Technologie CMOS pour la Miniaturisation des Circuits RF

Une démarche originale pour le développement de composants passifs dans une filière industrielle consiste à effectuer un report des contraintes en performances sur les caractéristiques électriques des matériaux utilisés en couches minces. Nous présentons dans cet article la démarche adoptée à travers trois phases clés du développement d’une technologie faibles coûts de composants passifs intégrés en filière CMOS. Le développement et la caractérisation de films minces d’oxyde de titane et de tantale. L’intégration de films résistifs d’oxynitrure de titane en filière industrielle et la modélisation électrique d’inductances spirales intégrées en CMOS

Phytochemicalanalysis,cytotoxic,antioxidant,andantibacterial activities of lichens

© 2020 Noura Aoussar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. Lichens present a complex symbiotic relationship between a filamentous fungus, photoautotrophic partner (algae or cyanobacteria), and bacterial community. The Objective of the Study. This study aimed at investigating the chemical composition and cytotoxic, antioxidant, and antimicrobial activities of acetone extracts of Moroccan Evernia prunastri (E. prunastri), Ramalina farinacea (R. farinacea), and Pseudevernia furfuracea (P. furfuracea). Materials and Methods. The phytochemical analysis was carried out by HPLC-UV. The cytotoxic effect was assessed on human prostate cancer (22RV1), human colon carcinoma (HT-29), human hepatocellular carcinoma (Hep-G2), and Hamster ovarian cancer (CHO) cells lines by WST1 assay. The antioxidant power was assessed by DPPH and FRAP assays. The antibacterial effect was obtained using the broth microdilution method. Results. The findings of phytochemical analysis showed that the lichens studied possess interesting bioactive molecules such as physodalic acid, evernic acid, and usnic acid, as well as protocetraric acid. According to the American National Cancer Institute guidelines, the WST-1 test showed that all crude extracts did not show significant cytotoxic effects against all concerous cell lines, and IC50 values ranged from 42.30 to 140.24 µg/mL. Regarding the antioxidant activity, P. furfuracea extract showed the highest free-radical-scavenging ability (IC50 = 498.40 µg/mL). The most potent antibacterial extract was recorded for P. furfuracea extract with a minimum inhibitory concentration (MIC) ranging from 0.039 to 0.31 mg/mL. Conclusion. In this research work, we report that the studied lichen extracts exhibit an important biological effect, supporting that lichens represent a hopeful source of original natural products for the research of new bioactive molecules having a pharmaceutical interest

Simulation of mesa structures for III-V semiconductors under ion beam etching

An argon Ion Beam Etching (IBE) simulation model has been developed to investigate the mesa profile evolution in III-V semiconductors' technology. Particular attention has been focused on the sputtering yield angular dependence effect, on the influence of the material and 2D-morphology of the mask onto the pattern transfer. Experimental sputtering yield versus ion incidence angle is injected into the simulation model. The equations which govern the surface evolution, stem from the current method of characteristics. The simulated profiles show that the trenching phenomenon can appear by only considering the variation of the sputtering yield versus the etched surface canting. This is obtained when neither the ion reflection nor the electric field line deviation are taken into account. On the other hand, the slope transfer from the mask to the GaAs and InP substrates is studied

Properties of deep etched trenches in silicon: Role of the angular dependence of the sputtering yield and the etched species redeposition

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Modelling of fluorine based high density plasma for the etching of silica glasses

International audienceAn etching simulator has been developed to study the etching of commercial silica glass (Pyrex®, D263®, AF45®, and Vycor®) in a SF6/Ar inductively coupled plasma (ICP) discharge. The etching model is based on the development of the plasma kinetic model coupled to a two dimensional (2D) Monte Carlo cellular surface model to predict the etched surface morphology as a function of the operating conditions. The SF6/Ar plasma model allows us to predict the neutral and ion species fluxes, as well as the density and the temperature of electrons, as a function of the reactor operating conditions. Such output parameters are used as input parameters in both the sheath and etching models. The 2D Monte Carlo cellular model is based on the representation of both the substrate and the mask by uniform cells, which each represents a real number of sites. The preferential redeposition mechanism of the etched products on the metallic sites seems to play an important role on the formation and the propagation of the etched surface roughness. The results obtained by the model are compared with the experimental results for etching rate and roughness. A satisfactory agreement between the experimental results and the model concerning the etching rate and the etched surface morphology has been obtained for different glasses

Etching studies of silica glasses in SF6/Ar inductively coupled plasmas: Implications for microfluidic devices fabrication

International audienceTo fabricate microlaboratories, commercially available silica glasses represent a good alternative to the expensive quartz or fused silica substrates. Therefore, the authors have here investigated the behavior of four of them-Vycor, Pyrex, D263, and AF45-in SF6 and SF6/Ar inductively coupled plasmas. Using Vycor, a material close to pure SiO2, as a reference, they demonstrated that the etch rate negatively correlates with the global content in metallic oxides. However, no such clear trend was found for the surface roughness and they hypothesize that the large asperities (>500 nm) sometimes observed might be due to local variation in the glass surface composition. Furthermore, investigations on the influence of the plasma conditions (i.e.,source power, dc self-bias, gas mixture, and pressure) on the etch rate, surface chemistry, and surface morphology, as well as positive ion current and fluorine concentration measurements, enable them to unravel an ion enhanced chemical etching mechanism, where stronger ion assistance is needed when more metallic oxides are present. By increasing the ion to neutral flux ratio, they consequently could, for all the materials, reduce the surface roughness to less than 5 nm while maintaining etch rates around 150 nm/min. These conditions have further been used to optimize pattern transfer experiments

Investigation of point defect generation in dry etched InP ridge waveguide structures

International audienceWaveguides engraved in InP by dry etching, reactive ion etching and inductively coupled plasma ͑ICP͒, were studied by cathodoluminescence. The dry etching processes were found to induce nonradiative recombination centers, which reduce the luminescence emission from the ridge structures. In addition, the ICP process introduced intrinsic defects, probably In vacancy related defects, which were generated at the dielectric cap/InP interface at the ridge to

Composants passifs intégrés en technologie CMOS pour la miniaturisation des circuits RF

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