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Article Dans Une Revue Journal of Vacuum Science & Technology A Année : 2008

Molecular dynamics simulations of GaAs sputtering under low energy argon ion bombardment

Résumé

Results from molecular dynamics (MD) simulations of low-energy (50–200 eV) Ar+ ion bombardment on (110) GaAs surfaces are reported. A new analytical bond-order potential, originally developed for molecular beam epitaxy studies, is used and tested in the context of etching to investigate the nature and effects of physical sputtering on GaAs compounds. It is found that a thermal desorption model, which accounts for long time scale phenomena between MD simulated impacts, is necessary to achieve steady state sputtering. An initial rapid etch of both atomic species is observed up to 4x10^16 ions/cm2 fluence with preferential sputtering of Ga atoms. At high fluences, simulations show the formation of an As-rich layer on the top surface, a subsurface enrichment of Ga, and a return to stoichiometry deeper in the solid. More than 97% of sputtered or desorbed species appear to be Ga or As atoms; sputtering of GaAs molecules is negligible. All these observations are in agreement with published experimental results. Finally, a significant fraction of the atoms leave the surface with more than 10% of the incident ion energy, which could alter passivation layers on sidewalls during etching.
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Dates et versions

hal-00462479 , version 1 (09-03-2010)

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E. Despiau-Pujo, Pascal Chabert, D.B. Graves. Molecular dynamics simulations of GaAs sputtering under low energy argon ion bombardment. Journal of Vacuum Science & Technology A, 2008, 26, pp.274. ⟨10.1116/1.2836408⟩. ⟨hal-00462479⟩
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