Description succincte
(Anglais)
|
This project aims to close the big gap between fundamental gas phase and condensed phase electron dissociation studies performed under idealized conditions and the real process conditions prevailing in direct write, gas assisted focused electron beam induced processing (FEBIP): notably high-vacuum, high electron fluxes, and a dynamically growing deposit (or etch pit). For in-situ characterization of the FEBIP process we will exploit a TESCAN Lyra FIB-SEM instrument equipped with a suite of analytical detectors developed in the European UnivSEM project: secondary ion mass spectrometry (SIMS), energy dispersive X-ray spectroscopy (EDX), cathodoluminescence (CL), Raman, and atomic force microscopy (AFM). The above complementary analysis techniques, all integrated to the FEBIP system, will enable us to monitor the growth and etching process with respect to its in-situ dissociation chemistry and pave the way for a fundamental understanding of electron-adsorbate interactions in scanning electron microscopes (SEMs) with their high-vacuum conditions and open the way to a better control of deposit material compositions, especially pure metal and diamond-like carbon material.
|
Résumé des résultats (Abstract)
(Anglais)
|
Investigations were performed with newly developed in-situ equipment for SEM integrated gas injection systems having a large thermal management capability (up to 250°C) during direct write focused electron beam induced deposition (FEBID). Novel organic and inorganic precursor compounds with an up to now prohibiting low vapour pressure could be successfully tested for direct writing of nanostructures containing silver, ruthenium, cobalt, cobalt-iron, gold, copper, and platinum. This opens a rich portfolio of new organometallic precursors to be tested for FEBID from the communities of CVD (chemical vapour deposition) and ALD (atomic layer deposition) as well as novel perspectives to control electron induced chemistry. The deposits obtained from the metal-carboxylate, -carbonyl, -hexafluoroacetate, and -chloroamino compounds were characterized via Raman, SEM, EDX, and FIBSIMS to elucidate the dissociation processes triggered by electron irradiation of adsorbates with respect to bulk precursor material as well as to understand the thermally induced processes of fragment desorption, autocatalytic decomposition of impinging molecules, and grain clustering. It was found that for each adsorbate molecule specific temperature windows exist which allow for physisorption desired in the FEBID process, and that the balance of above electron triggered and heat induced contributions is individual to the nature of the chemical compound for obtaining a pure metal deposit versus a granular material (nanocrystals embedded in carbon matrix). The highlight is the breakthrough in deposition of silver by FEBID which has not yet been achieved so far by the international community. The ex-situ characterization of the FEBID materials from the varying precursors with respect to magnetic properties, nanophotonic applications, or gas sensors is still ongoing in our CELINA COST - Action partners’ institutes.
|
