Abstract
In this work, we investigated both etching characteristics and mechanisms of Au thin films using Cl<sub>2</sub>/Ar gas mixture in an inductively coupled plasma (ICP) system. For these purposes, a combination of experimental methods and modeling was used. It was found that an increase in Ar mixing ratio under constant operating conditions causes non-monotonic behavior of Au etch rate, which reaches a maximum 80% Ar. A study of surface composition using X-ray photoelectron spectroscopy (XPS) showed that the etching in chlorine-rich plasma is escorted by accumulation of AuCl<sub>x</sub> on the etched surfaces. Langmuir probe measurements indicated a noticeable sensitivity of both electron temperature and electron density to the change of Ar mixing ratio while 0-dimensional model of volume kinetics showed monotonic change of both densities and fluxes of active species such as chlorine atoms and positive ions. However, analyses of surface kinetics showed that the non-monotonic etch rate behavior may be produced by the concurrence of physical and chemical pathways in ion-assisted chemical reaction.
Published Version
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