Charge Neutralization of Medium Energy H and 4He Ions Backscattered from Solid Surfaces, Effects of Surface Cleaning
Experiments on charge states of H and 4He backscattered from silicon and gold surfaces in the energy range 25–190 keV have been extended to investigate surface impurity and surface cleaning effects. The average charge state of 4He scattered from iodine or gold impurities on silicon surfaces was close to that of 4He scattered from silicon at the same energy. Argon bombardment cleaning of a gold surface caused substantial changes in neutralization for both 4He and H, similar to results of Phillips in the case of hydrogen, and suggestive of more than one neutralization mechanism. The results are consistent with a neutralization step occurring outside the surface as the particle leaves. It is pointed out, however, that at low energies, 0.5–5 keV for 4He, preferential neutralization of ions which penetrate beyond the surface has been inferred from electrostatic analyzer data.
KeywordsSilicon Surface Incident Energy Gold Surface Medium Energy Polycrystalline Gold
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