Mass Spectrometric Study of Energy Distributions of Sputtered Copper Monomer under Low Energy Ar~+ Ions Bombardments

摘要

Secondary neutral mass spectrometry (SNMS) involving post ionized sputtered neutrals, has been used to determine the energy distribution of neutral Cu_1 particles sputtered from a polycrystalline Cu target by normally incident Ar~+ ions with energies ranging between 100 - 240 eV. A magnetically confined arc discharge 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~(-1.72). This asymptotic behavior is discussed in view of Sigmund-Thompson model of the random collision cascade. The average energy of the sputtered atoms increases from 7 eV to 9 eV within the ion energy range of 100 - 240 eV.