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

Cathodoluminescence Study of InP Photonic Structures Fabricated by Dry Etching

International audienceRidge waveguides fabricated by inductively coupled plasma (ICP) etching using chlorine-based gases were studied by spectrum image cathodoluminescence (CL). Structures with different dimensions (height and width) were studied, evidencing the generation of defects during ICP processing. Using the CL spectrum images, the distribution of the stresses induced by the defects was mapped. The residual stresses depend on the dimensions of the waveguides. Using finite-element analysis the strain distribution was reproduced. The initial strain conditions provided a picture of the distribution of the defects generated by the etching process, showing differences between the etched floor, the side-walls of the waveguides, and the unetched top surface. The possible mechanisms for defect formation, as well as the possible identity of the defects, are discussed

Modeling of the chemically assisted ion beam etching process: Application to the GaAs etching by Cl-2/Ar+

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Etude de la stratosphere polaire. Rapport final

SIGLEINIST RP 185 (2488) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

The NetLander atmospheric instrument system (ATMIS): Description and performance assessment

The pointwise meteorological observations of the Viking Lander and Mars Pathfinder as well as the orbital mapping and sounding performed by, e.g., Mariner 9, Viking Orbiters and the Mars Global Surveyor have given a good understanding of the basic behaviour of the Martian atmosphere. However, the more detailed characterisation of the Martian circulation patterns, boundary layer phenomena and climatological cycles requires deployment of meteorological surface networks. The European NetLander concept comprising four well-instrumented landers is being studied for launch in 2005 and operations spanning at least a Martian year in 2006-2008. The landers are to be deployed to areas in both Martian hemispheres from equatorial regions to low mid-latitudes. The NetLander atmospheric instrument system (ATMIS) on board each of the landers is designed to measure atmospheric vertical profiles of density, pressure and temperature during the descent onto the surface, as well as pressure, atmospheric and ground temperatures, wind, atmospheric optical thickness and humidity through a full Martian year, possibly beyond. The main operational objective of this meteorological experiment is to provide a regular time series of the meteorological parameters as well as accelerated measurement campaigns. Such a data set would substantially improve our understanding of the atmospheric structure, dynamics, climatological cycles, and the atmosphere-surface interactions. The ATMIS sensor systems and measurement approaches described here are based on solutions and technologies tested for similar observations on Mars-96, Mars Pathfinder, Huygens, and Mars Polar Lander. Although the number of observation sites only permits characterisation of some components of the general circulation, the NetLander ATMIS will more than double the number of in situ vertical profiles (only three profiles - two from Viking Landers and one from Mars Pathfinder - are currently available and as envisioned at the time of writing, none of the 2001 and 2003 landers' payloads include entry phase measurements of pressure or temperature), perform the first in situ meteorological observations in the southern low- and mid-latitudes and provide the first simultaneous in situ multi-site observations of the local and general circulation patterns, in a variety of locations and terrains. As such, NetLander ATMIS will be the precursor of more comprehensive meteorological surface networks for future Mars exploration. © 2000 Elsevier Science Ltd. All rights reserved