Energy distributions and yields of sputtered neutral copper monomers and dimers determined by mass spectrometry. [100-1000 EV range]

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:5122859

Hamed, H A

Secondary neutral mass spectrometry (SNMS) involving positionized sputtered neutrals, has been used to determine the relative yield and energy distribution of neutral Cu/sup 1/ and Cu/sup 2/ particles sputtered from a polycrystal Cu target by normally incident Ar/sup +/ ions with energies ranging 100-250 eV. A magnetically confined arc discharge (plasma) at low Ar pressure, located in the source region of the mass spectrometer, has been used for ion bombardment of the target, and simultaneously for electron impact post-ionization of sputtered neutrals ejected normal to the target. The energy distribution of sputtered neutral atoms was found to exhibit a peak at an ejection energy of 4.2 eV and tail-off above this energy, approximately, as E/sup -1/ /sup 72/. This asymptotic behavior is discussed in view of the available theoretical models, namely the Sigmund-Thompson model of the random collision cascade. The average energies of sputtered atoms show slight increase with the Ar/sup +/ ion bombarding energies. The average energy increases from 7 eV at ion energy of 100 eV to 9 eV at an ion energy of 250 eV. The energy distribution of sputtered neutral Cu/sub 2/ molecules is found to be narrower than that of the ejected atoms and is shifted to smaller ejection energies compared with the corresponding results of Cu/sub 1/ atoms and behave differently as the bombarding Ar/sup +/ ion increased. The ratio of the Cu/sub 2//Cu/sub 1/ (molecule/atom) increased with Ar/sup +/ ion bombarding energies to about 7.4% at 240 eV.

• Research Organization: Delaware Univ., Newark (USA)
• OSTI ID: 5122859
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ARGON IONS
ATOMS
CHARGED PARTICLES
COLLISIONS
COPPER
CRYSTALS
DIMERS
ELEMENTS
ENERGY RANGE
ENERGY SPECTRA
EV RANGE
EV RANGE 100-1000
IONS
MASS SPECTROSCOPY
METALS
MONOMERS
POLYCRYSTALS
SPECTRA
SPECTROSCOPY
SPUTTERING
TRANSITION ELEMENTS
YIELDS