Net sputtering rate due to hot ions in a Ne-Xe discharge gas bombarding an MgO layer

Abstract

An analytical method is developed for determining net sputtering rate for an MgO layer under hot ions with low energy (<100 eV) in a neon-xenon discharge gas at near-atmospheric pressure. The primary sputtering rate is analyzed according to spatial and energy distributions of the hot ions with average energy, Ehi, above a threshold energy of sputtering, Eth,i, multiplied by a yield coefficient. The threshold energy of sputtering is determined from dissociation energy required to remove an atom from MgO surface multiplied by an energy-transfer coefficient. The re-deposition rate of the sputtered atoms is calculated by a diffusion simulation using a hybridized probabilistic and analytical method. These calculation methods are combined to analyze the net sputtering rate. Maximum net sputtering rate due to the hot neon ions increases above the partial pressure of 4% xenon as EhNe becomes higher and decreases near the partial pressure of 20% xenon as ion flux of neon decreases. The dependence due to the hot neon ions on partial pressure and applied voltage agrees well with experimental results, but the dependence due to the hot xenon ions deviates considerably. This result shows that the net sputtering rate is dominated by the hot neon ions. Maximum EhNe (EhNe,max = 5.3 − 10.3 eV) is lower than Eth,Ne (19.5 eV) for the MgO layer; therefore, weak sputtering due to the hot neon ions takes place. One hot neon ion sputters each magnesium and each oxygen atom on the surface and distorts around a vacancy. The ratio of the maximum net sputtering rate is approximately determined by number of the ions at Ehi,max multiplied by an exponential factor of –Eth,i/Ehi,max.

White light interferometry for quantitative surface characterization in ion sputtering experiments

“…A few examples of applying this method are provided when used for (i) characterization of ion beam profiles and crater shapes yielding accurate SY estimates, (ii) overlap alignment of a multiple ion beams system, (iii) time-to-depth calibration in sputter depth profiling, and (iv) characterization of surface processing of materials by ion beams. For sputtering yield and rate estimates, the presented results demonstrate an alternative experimental approach to generate reference data for many materials and technological applications [4,[7][8][9][10][11][12][13] under bombardment with both commonly used atomic ions and relatively new molecular and cluster ions and help to resolve the problem of time or primary ion fluence to depth conversion.…”

Characterization of Surface Modifications by White Light Interferometry: Applications in Ion Sputtering, Laser Ablation, and Tribology Experiments

“…6,9,[33][34][35][36] In addition, this approach is capable of accurate quantifying sputtering rates for organic materials and solids under bombardment with a variety of primary species, commonly used atomic ions and relatively new molecular and cluster ions, such as in Refs. 37, 38.…”