P. Viaris de Lesegno

Auger electron emission by ion bombardment of light metals

Abstract The energy distribution of secondary electrons ejected from a metallic target upon ion bombardment (Ar + , 10 keV) is studied with a 180° magnetic analyser, particularly in the vicinity of the Auger peaks that appear in the electron spectra of the light metals (Li, Be; Na, Mg, Al, Si). A qualitative explanation based on the correlation diagrams which described the evolution of the electronic levels during the collision of two atoms inside the target is proposed to interpret the variation of the Auger peak intensity with the atomic number of the target.

Ar+ excited aluminium Auger electron emission from Cu-Al alloys

The aluminium Auger electron emission from Cu-Al alloys in solid solution bombarded with 2–16 keV Ar+ ions is studied as a function of the Al concentration. A linear law is observed for the intensity of the high energy Auger peak at 76 eV which originates only from the primary asymmetric collisions Ar → Al where two vacancies are created in the 2p level of the Al atom. On the contrary, a parabolic law is found for the intensity of the principal Auger peak at 63.5 eV (one Al 2p vacancy) which originates from the asymmetric collisions Ar → Al and from the symmetric collisions Al → Al together. The proportion of asymmetric collisions among collisions effective for the principal Auger emission from pure aluminium can be deduced from these results. It appears as an increasing function of the bombardment energy: its value is nearly equal to 6% at 10 keV and 18% at 15 keV.

On the origin of ion-induced Auger electron emission from metals

Abstract Auger electron emission by ion bombardment of solids originates from two kinds of collision: asymmetric collisions of the incident particles with the target atoms and symmetric collisions of the target atoms between themselves. Their relative contributions for Auger emission are discussed.

Multicharged Secondary Ions from Light Metals (Mg, Al, Si)

Only light metals (Mg, Al, Si) bombarded with noble gas ions in the some keV energy range show a non-negligible emission of true multicharged secondary ions [1]. The few multicharged ions observed from heavy metals at very high bombardment density [2] are in fact mostly created by direct ionization of sputtered neutral atoms by primary ions in the vacuum at some distance from the target [3,4].