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

Characterizations of CNx thin films made by ionized physical vapor deposition

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Characterization of carbon nanotubes and carbon nitride nanofibres synthesized by PECVD

This paper presents a novel dual plasma enhanced chemical vapor deposition (PECVD) process developed to grow carbon nitride nanofibres (CN-NFs) at room temperature (RT) and its basic version used to grow multi-walled carbon nanotubes (MWCNTs) at temperatures as low as 550 °C. The dual process alternates two low pressure-high density plasmas, one inductively coupled (ICP) and the other one excited by distributed electron cyclotron resonance (DECR). MWCNTs can be synthesized using only the DECR plasma source. The paper focuses on the comparison between CN-NFs and MWCNTs detailing their structure as revealed by transmission electron microscopy (TEM), X-ray photo electron spectroscopy (XPS) and Raman spectroscopy

Examination of the electrochemical reactivity of screen printed carbon electrode treated by radio-frequency argon plasma

The surface of screen printed carbon electrode (SPCE) with partially blocked surface was treated by argon plasma in order to improve their electrochemical performances. The argon plasma was generated by a radio-frequency electrical discharge at low pressure. Study of the electrode surface by scanning electronic microscopy (SEM) has revealed a significant change of the morphology of the SPCE surface after plasma pre-treatment. The electrochemical reactivity of the SPCEs was characterized using cyclic voltammetry. A drastic enhancement of the SPCEs electrochemical reactivity was highlighted after plasma pre-treatment. The effect of biasing the SPCE surface during the plasma treatment has been investigated and showed that depending on the nature of plasma treatment, the same electrode could show a radial or planar diffusion. Keywords: Screen printed carbon electrode (SPCE), Argon plasma treatment, Cyclic voltammetry, Microelectrodes arrays, Electrochemical reactivit

Desorption of ultraviolet‐ozone oxides from InP under phosphorus and arsenic overpressures

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Thermal conductivity of aluminium nitride thin films prepared by reactive magnetron sputtering

International audienceThe relationship between thermal conductivity and microstructures of aluminium nitride films is reported. Films were deposited on silicon substrates by magnetron sputtering of a pure Al target in nitrogen argon plasma at low temperatures (<300 °C) with thickness ranging from 150 to 3500 nm. Balanced and unbalanced magnetron configurations were used for different nitrogen contents in the gas phase. Various microstructures were thus created and their thermal conductivity was measured with the transient hot strip technique. Depending on the crystalline structure of the films, the bulk thermal conductivity of the AlN films at room temperature varied between 2 and 170 W m−1 K−1. Unbalanced magnetron allowed achieving highly dense (0 0 2) oriented AlN films with a grain size in the 100 nm range, a low oxygen content close to 0.5 at% and a resulting bulk thermal conductivity as high as 170 W m−1 K−1. Such a crystalline quality resulted from the ion energy involved in the growth process. In contrast, balanced magnetron led to weakly textured AlN films containing 5 at% oxygen with a grain size in the 30 nm range and a resulting thermal conductivity ranging from 2 to 100 W m−1 K−1 depending on the microstructure. Otherwise, the thermal boundary resistance between AlN films deposited by unbalanced magnetron and the silicon substrate was found to be as low as 1.0 × 10−8 K m2 W−1. Such a value was in good agreement with the thickness of the interfacial amorphous layer determined in the 2 nm range by high resolution transmission electron microscopy

Preparation and characterization of ZnS/CdS bi-layer for CdTe solar cell application

International audienceIn this work, bilayer ZnS/CdS film was prepared as an improved window layer of CdTe solar cell. TEM was used to observe the cross section of the bilayer structure. The total thickness of ZnS/CdS film was about 60 nm, which could allow more photons to pass through it and contribute to the photocurrent. Optical properties of the bilayers were investigated using UV-vis spectroscopy. Compared with poor transmission of standard CdS film in the short wavelength range of 350-550 nm, the transmission of ZnS/CdS was improved and reached above 50%. The ZnS/CdS was annealed with CdCl2. X-ray photoelectron spectroscopy (XPS) was used to investigate its chemical properties. A possible diffusion between CdS and ZnS was observed after annealing. The efficiency of standard CdS/CdTe solar cell was 9.53%. The device based on ZnS/CdS window layer had a poor 6% efficiency. With annealing treatment on ZnS/CdS layer, the performance was improved and reached 10.3%. In addition, the homogeneity of solar cell performance was improved using ZnS/CdS window layer. A thin ZnS layer was quite effective to reduce the possible shunt paths and short parts of window layer and consequently contributed to fabrication of a homogeneous CdTe solar cell