Accession Number : ADA132539

Title :   An Investigation of Cascade Energy Density Effects Using Classical Trajectory Simulations of Sputtering by Molecular Ions.

Descriptive Note : Master's thesis,


Personal Author(s) : Mason,William A

PDF Url : ADA132539

Report Date : Jun 1983

Pagination or Media Count : 92

Abstract : The NPS computer simulation model was modified to study sputtering by molecular ions. The simulations were performed on a Cu(111) surface for normally incident 02+ ions at 0.5, 1.25, 2.5, and 5.0 kev/ion. The molecule's angular orientation was both set at specific values and randomly determined. The normalized energy distribution of sputtered atoms for two energy ranges, 0-20 and 0-3 ev/sputtered atom, and the sputtering yeild rations were investigated. The 0-20 ev/sputtered atom energy distributions show distinct peaks at 1.8 ev which are insensitive to incident energy, energy density, and molecular orientation. Simulations indicate that there may be fine structure in the 0-3 ev/sputtered atom range with a cascade interaction unique to molecular sputtering. For a number of molecular orientations which produce very different cascade overlaps, the sputtering yield ratios do not correlate with the degree of overlap. The energy density of a cascade is not an accurate predictor of the sputtering yield ratio. (Author)

Descriptors :   *Copper, *Molecular ions, *Sputtering, *Computerized simulation, Cascades(Fluid dynamics), Energy levels, Oxygen, Collisions, Trajectories, Distribution, Current density, Ratios, Computer aided diagnosis, Theses

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE