Ab initio study of subsurface diffusion of Cu on the H-passivated Si(001) surface

Fuente: arXiv
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Autores principales: Rodriguez-Prieto, A., Bowler, D. R.
Formato: Preprint
Publicado: 2024
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author Rodriguez-Prieto, A.
Bowler, D. R.
author_facet Rodriguez-Prieto, A.
Bowler, D. R.
contents In this paper we use density-functional theory calculations to analyze both the stability and diffusion of Cu adatoms near and on the H-passivated Si(001) surface. Two different Cu sources are considered: depositing Cu from vacuum, and contaminating Cu outdiffusing from bulk Si. Deposited Cu from vacuum quickly moves subsurface to an interstitial site in the third Si layer (T2). Once there, Cu adatoms enter a subsurface zigzag migration route between T2 and another subsurface site, T2->HSL->T2, along the dimer row direction. Contaminating Cu outdiffusing from bulk is found to be a fast diffuser along both parallel and perpendicular directions to the dimer row when far from the surface. It is attracted to the layers close to the surface and becomes trapped at an interstitial site located at the sixth Si layer (T3). As the outdiffusing Cu atoms get closer to the surface, a channeling zigzag diffusion along the dimer row direction, similar to that one followed by deposited Cu from vacuum, is favoured over diffusion along the perpendicular direction. These results are consistent with previous experimental work done on similar systems and will motivate further experiments on the interesting interaction between Cu and Si surfaces.
format Preprint
id arxiv_https___arxiv_org_abs_2402_04804
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ab initio study of subsurface diffusion of Cu on the H-passivated Si(001) surface
Rodriguez-Prieto, A.
Bowler, D. R.
Materials Science
In this paper we use density-functional theory calculations to analyze both the stability and diffusion of Cu adatoms near and on the H-passivated Si(001) surface. Two different Cu sources are considered: depositing Cu from vacuum, and contaminating Cu outdiffusing from bulk Si. Deposited Cu from vacuum quickly moves subsurface to an interstitial site in the third Si layer (T2). Once there, Cu adatoms enter a subsurface zigzag migration route between T2 and another subsurface site, T2->HSL->T2, along the dimer row direction. Contaminating Cu outdiffusing from bulk is found to be a fast diffuser along both parallel and perpendicular directions to the dimer row when far from the surface. It is attracted to the layers close to the surface and becomes trapped at an interstitial site located at the sixth Si layer (T3). As the outdiffusing Cu atoms get closer to the surface, a channeling zigzag diffusion along the dimer row direction, similar to that one followed by deposited Cu from vacuum, is favoured over diffusion along the perpendicular direction. These results are consistent with previous experimental work done on similar systems and will motivate further experiments on the interesting interaction between Cu and Si surfaces.
title Ab initio study of subsurface diffusion of Cu on the H-passivated Si(001) surface
topic Materials Science
url https://arxiv.org/abs/2402.04804