材料期刊网

In the sputtering of a Mo-92-Mo-100 target induced by 5 keV Ar ions, both static and dynamic Monte Carlo simulation programs have been used to estimate both the angular variations in isotopic enrichment from zero to high fluences, and the momentum flux ratios as a function of surface depth at the zero fluence. The calculations show that the isotopic ratio in the near-normal direction is positive and quite large at the zero fluence, then it decreases with increasing fluence. The calculations also show that the difference between the near-normal isotopic ratio and the oblique isotopic ratio is large and positive at both the zero and the high fluences, then this difference minimizes at a low fluence between the two fluence limits. The calculations indicate that depth-dependent momentum asymmetry significantly exists in the near-surface region.