A seminar given by
Dr. Anne Lafosse, professor at the Paris-Saclay University, ISMO laboratory, Saclay (France)
Quantifying the unavoidable contribution of electron – supported molecular film interactions – Nanolithography and astrophysics
Abstract: What do chemical enrichment of the interstellar medium and nanolithography processes have in common? Electron-induced processes within molecular films deposited, respectively, on interstellar dust grains and on substrates to be functionalized. The interaction of high-energy radiations (X-ray, ions, electrons) with a condensed medium leads to the formation of low-energy (<20 eV) secondary electron bursts. These electrons created within the irradiated medium contribute efficiently to its chemical modification. In all application contexts (astrochemistry, radiation damage, nanolithography), one of the important issues is to quantify the efficiency of the induced processes, in terms of yields, but also of effective cross sections and required doses.
The approach proposed by the “electron-solids” group is to study directly the effects of electron irradiation on interfaces deposited on substrates by combining: (i) quantitative mass analysis of neutrals desorbing during irradiation (ESD) and (ii) analysis of the deposits before and after irradiation by temperature programmed désorption (TPD) and vibrational spectroscopy HREELS (High Resolution Electron Energy Loss Spectroscopy).
Two systems will be discussed and the derived quantitative markers presented:
– the decomposition under electron irradiation of a film of a halogenated unsaturated compound potentially of interest in the development of EUV lithographic resists,
– the non-thermal desorption from molecular ice of methanol CH3OH, with an interpretation linked to XESD (X-ray induced electron-stimulated desorption) processes.
Bio : Anne Lafosse is full professor at the University of Paris-Saclay. She performs her research in the laboratory ISMO (Institut des Sciences Moléculaire d’Orsay). She is the team leader of the Surface chemistry & slow electrons team.