Effect of Gas Mixing Ratio on Etch Behavior of Y2O3 Thin Films in Cl-2/Ar and BCl3/Ar Inductively Coupled Plasmas

Abstract

This paper reports the results of a model-based analysis of the etch mechanism for the Y2O3 thin films in the Cl-2/Ar and BCl3/Ar inductively coupled plasma It was found that the BCl3/Ar plasma provides higher etch rate (except the case of pure BCl3 and Cl-2 gases) as well as shows the non-monotonic dependence of the etch rate on the Ar mixing ratio Plasma diagnostics by Langmuir probes indicated the noticeable influence of Ar mixing ratio on electron temperature and total density of positive ions Using the model-based analysis of plasma chemistry and etch kinetics, it was demonstrated that the behavior of the Y2O3 etch rate in both gas mixtures generally corresponds to the neutral-flux-limited etch regime of the ion-assisted chemical reaction while the obtained differences cannot be explained assuming the Cl atoms to be the main chemically active species Probably, in the BCl3-bases plasmas, the etch kinetics is significantly influenced by the BCl radicals (C) 2010 The Japan Society of Applied Physics