Abstract
An improved version of the time-of-flight spectrometer “ASSIMOF” is described, capable of obtaining secondary ion energy spectra in the energy range 10 eV to 10 keV, with an energy resolution (for copper) varying between 1.4 and 17%. Application of the instrument to a study of the ion emission due to 600-μA cm −2, 47-keV Ar + bombardment of 5N polycrystalline copper at a scattering angle of 84° and oxygen partial pressures between 3 × 10 −8 and 1 × 10 −5 torr demonstrates the existence of a number of mechanisms for the creation of an ionized state on particles ejected owing to collisions describable by the random cascade theory of sputtering. In addition, it is shown that at this geometry the probability of ionization convoluted with the probability of ejection, for particles with energies equal to or exceeding the direct target recoil energy, is higher for non-random than for random collision events. Evidence is presented to suggest that experiments designed to investigate the physical mechanisms associated with the ionization phenomena should be restricted to primary ion doses not exceeding 10 14 ions cm −2.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call