Objectif The objectives of the HESSILSIL Action were to: -grow epitaxially ultra-thin films of FeSi2 in its semiconducting phase on silicon -characterise and study these heterostructures by a number of in situ and ex situ techniques -examine the bandgap engineering problem with ternary semiconducting silicides (both theoretically and experimentally) -fabricate integrated photo-detectors.New materials were sought for the fabrication of optoelectronic devices. Semiconducting silicides are alternative materials to compound semiconductors and organic materials. They could well provide better photodetectors, optical fibre links and on chip electrooptic interconnects. An attractive feature of the use of silicides is the wide range of possiblities for optical tuning inherent in the material.During this research iron disilicade silicon heterostructure elaboration has received special attention. Iron disilicide in its beta semiconducting phase is a promising material because the expected energy gap is around 0.9 eV, and nicely fits the 1.5 micron optical transmission window of silica optical fibres. The following results have been obtained:iron/silicon (III) and iron silicon (100) interface development at room temperature (these interfaces may give rise to precursor phases which control epitaxial growth at higher temperatures);epitaxial growth of beta-iron disilide on silicon (III) and silicon (100) by various epitaxial techniques;determination of the morphology of the films and its dependence on various elaboration parameters such as thickness and temperature;determination of the band gap, which is about 0.9 eV;determination of the interface structure between silicide and silicon by X-ray standing wave techniques;determination of the theoretical ternary silicide phase diagram (iron(x) cobalt(y) silicon(z));observation of thin beta-iron disilicide strained layers and a metallic semiconducting phase transition.APPROACH AND METHODS The silicides were grown on silicon substrates by solid phase epitaxy (SPE), co-evaporation techniques, chemical beam epitaxy (CBE) and molecular beam epitaxy (MBE). Both the structural and electronic properties of the silicide heterostructures were to bestudied. The structural properties were characterised by: -glancing incidence X-ray diffraction, X-ray standing waves and extended X-ray absorption fine structures (EXAFS) -low and high-energy electron diffraction -electronic microscopy and micro-analysis -scanning tunnelling microscopy (STM) -electron energy loss fine structure (EELFS) and related techniques. Electronic properties were characterised by: -UV and X-ray photoemission -Auger spectroscopy -Bremsstrahlung isochromat spectroscopy (BIS) and related techniques -electrical and optical characterisation techniques. PROGRESS AND RESULTS During this Action, FeSi2-Si heterostructure elaboration has received special attention. Iron di-silicide (FeSi2) in its semiconducting phase is a promising material because the expected energy gap is around 0.9 eV, and nicely fits the 1.5 micron optica l transmission window of silica optical fibres. The following results have been obtained: -Fe/Si(111) and (100) interface development at room temperature; these interfaces may give rise to precursor phases which control epitaxial growth at higher temperatures -epitaxial growth of -FeSi2 on Si(111) and Si(100) by SPE, RDE, MBE and CBE techniques -determination of the morphology of the films and its dependence on various elaboration parameters such as thickness and temperature -determination of the band gap, which is about 0.9 eV -determination of the interface structure between silicide and silicon by X-ray standing wave techniques -determination of the theoretical ternary silicide phase diagram (FexCoySiz). -observation of thin -FeSi2 strained layers and a metallic - semiconducting phase transition. POTENTIAL Successful exploitation of the tuning possibilities will lead to a breakthrough in heterostructures in silicon and related compounds, with the eventual production of better silicon-compatible photodetectors and optical fibre links. The wavelength can be tuned by using ternary silicides. Since the silicide fabrication techniques are compatible with current silicon technologies, the know-how obtained in this Action can be transferred immediately to development and production. Champ scientifique engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensorsoptical sensorsengineering and technologymaterials engineeringcoating and filmsnatural scienceschemical sciencesinorganic chemistrymetalloidsnatural sciencesphysical sciencesopticsfibre opticsnatural sciencesphysical sciencesopticsspectroscopy Programme(s) FP2-ESPRIT 2 - European strategic programme (EEC) for research and development in information technologies (ESPRIT), 1987-1992 Thème(s) Data not available Appel à propositions Data not available Régime de financement Data not available Coordinateur Centre National de la Recherche Scientifique (CNRS) Contribution de l’UE Aucune donnée Adresse 1919 route de Mende 34033 Montpellier France Voir sur la carte Coût total Aucune donnée Participants (4) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire NATIONAL RESEARCH COUNCIL OF ITALY Italie Contribution de l’UE Aucune donnée Adresse Via Cineto Romano 42 00156 ROMA Voir sur la carte Coût total Aucune donnée UNIVERSITAT POLITECNICA DE MADRID Espagne Contribution de l’UE Aucune donnée Adresse RECTORADO, AVENIDA RAMIRO DE MAEZTU, 7 28040 MADRID Voir sur la carte Coût total Aucune donnée Università degli Studi di Roma Tor Vergata Italie Contribution de l’UE Aucune donnée Adresse Via Orazio Raimondo 1 00173 Roma Voir sur la carte Coût total Aucune donnée Université Pierre et Marie Curie - Paris VI France Contribution de l’UE Aucune donnée Adresse Place Jussieu 4 75252 Paris Voir sur la carte Coût total Aucune donnée
