Mass spectrometric characterization of BCl3/SF6 plasmas

Abstract

Significant increases in the etch rates of both GaAs and GaN have been observed with the addition of SF6 to BCl3plasmas. Mass spectrometric characterization of neutrals in these gas mixtures shows that increasing the SF6 percentage in the flow enhances the dissociation of BCl3, resulting in nearly 100% dissociation at 70% SF6. This increased dissociation is believed to be due to electron attachment heating. Both Cl and Cl2 mass intensities also maximize at 70% SF6. The detection of BClF and BCl2F suggest the possibility of reactions occurring between BCl and BCl2 radicals and fluorine, which may inhibit the recombination of Cl.