Emission of MCs+ secondary ions from semiconductors by caesium bombardment

The emission of MCs+ molecular ions sputtered from a variety of elemental (Si, Ge, a-C:H) and compound (GaAs, InP, InSb, ZnTe, ZnMnTe, ZnSe, CdS, CdSe, CdTe) semiconductors by Cs+ ion impact was investigated. The energy spectra of MCs+ species were found to be very similar to that of Cs+ ions but, in most cases, are shifted slightly (∼1 ev) to higher energies. The useful yields of MCs+ secondary ions range from 10-6 (for HCs+) to 10-4 and, for a given molecular species, are largely independent of the specimen. For a series of Ge1-xOx samples it was established that the GeCs+ intensity is constant up to an oxygen content of ∼10 at.% but the emission of GeOCs+ ions is prominent above this value and constitutes a competing ejection channel. (Author)