TY - JOUR
T1 - Molecular dynamics simulations of GaAs sputtering under low-energy argon ion bombardment
AU - Despiau-Pujo, Emilie
AU - Chabert, Pascal
AU - Graves, David B.
N1 - Funding Information:
The authors gratefully acknowledge discussions with Joe Végh. They are also indebted to C. F. Abrams for his version of a preexisting MD code. This work was financially supported by Thales Group.
PY - 2008
Y1 - 2008
N2 - 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 4× 1016 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.
AB - 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 4× 1016 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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U2 - 10.1116/1.2836408
DO - 10.1116/1.2836408
M3 - Article
AN - SCOPUS:40249118581
SN - 0734-2101
VL - 26
SP - 274
EP - 280
JO - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
JF - Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
IS - 2
ER -