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Formation of silicon nanodots via ion beam sputtering of ultrathin gold thin film coatings on Si.

El-Atwani O, Ortoleva S, Cimaroli A, Allain JP - Nanoscale Res Lett (2011)

Bottom Line: Structures of 11- to 14-nm Si nanodots are formed with normal incidence low-energy Ar ions of 200 eV and fluences above 2 × 1017 cm-2.In situ surface characterization during ion irradiation elucidates early stage ion mixing migration mechanism for nanodot self-organization.In particular, the evolution from gold film islands to the formation of ion-induced metastable gold silicide followed by pure Si nanodots formed with no need for impurity seeding.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA. oelatwan@purdue.edu.

ABSTRACT
Ion beam sputtering of ultrathin film Au coatings used as a physical catalyst for self-organization of Si nanostructures has been achieved by tuning the incident particle energy. This approach holds promise as a scalable nanomanufacturing parallel processing alternative to candidate nanolithography techniques. Structures of 11- to 14-nm Si nanodots are formed with normal incidence low-energy Ar ions of 200 eV and fluences above 2 × 1017 cm-2. In situ surface characterization during ion irradiation elucidates early stage ion mixing migration mechanism for nanodot self-organization. In particular, the evolution from gold film islands to the formation of ion-induced metastable gold silicide followed by pure Si nanodots formed with no need for impurity seeding.

No MeSH data available.


Related in: MedlinePlus

Spatial profile of the half-coated sample before and after irradiation. (a) Spatial profile of the XPS core level spectra of Au-4f and Si-2p before Ar+ 200 eV irradiation and (b) after irradiation. Position is plotted vertically along the sample where one region has a 20-nm Au film (top of Figure 1) and the bottom region only Si. (c-d) SEM images corresponding to the postirradiation condition for the Au-coated (c) and uncoated (d) regions. Si nanostructures are evidenced only in the region where Au was deposited noting that in (b) XPS Au-4f spectra are absent.
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Figure 1: Spatial profile of the half-coated sample before and after irradiation. (a) Spatial profile of the XPS core level spectra of Au-4f and Si-2p before Ar+ 200 eV irradiation and (b) after irradiation. Position is plotted vertically along the sample where one region has a 20-nm Au film (top of Figure 1) and the bottom region only Si. (c-d) SEM images corresponding to the postirradiation condition for the Au-coated (c) and uncoated (d) regions. Si nanostructures are evidenced only in the region where Au was deposited noting that in (b) XPS Au-4f spectra are absent.

Mentions: Figure 1a shows the spatial profile along a horizontal line to the sample surface with XPS core level peaks of Au 4f and Si 2p. The postirradiation data shown in Figure 1b and corresponding ex situ SEM images (Figure 1c,d) show the effect of the Au coating. An examination of the XPS spectrum in Figure 1b shows no sign of Au, yet the SEM images show nanopatterning only on the region where the Au was deposited. In that region, nanostructures with a diameter of roughly 11-14 nm were formed. Figure 2 shows a magnified image of the silicon dots after the irradiation process. To understand how the gold film affected the nanostructure formation, in situ XPS and LEISS were performed during the irradiation process on another sample fully coated with 10-nm gold. It should be noted here that while XPS is capable of probing the top 1-5 nm of the surface, LEISS probes only the first layer [11,12].


Formation of silicon nanodots via ion beam sputtering of ultrathin gold thin film coatings on Si.

El-Atwani O, Ortoleva S, Cimaroli A, Allain JP - Nanoscale Res Lett (2011)

Spatial profile of the half-coated sample before and after irradiation. (a) Spatial profile of the XPS core level spectra of Au-4f and Si-2p before Ar+ 200 eV irradiation and (b) after irradiation. Position is plotted vertically along the sample where one region has a 20-nm Au film (top of Figure 1) and the bottom region only Si. (c-d) SEM images corresponding to the postirradiation condition for the Au-coated (c) and uncoated (d) regions. Si nanostructures are evidenced only in the region where Au was deposited noting that in (b) XPS Au-4f spectra are absent.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211498&req=5

Figure 1: Spatial profile of the half-coated sample before and after irradiation. (a) Spatial profile of the XPS core level spectra of Au-4f and Si-2p before Ar+ 200 eV irradiation and (b) after irradiation. Position is plotted vertically along the sample where one region has a 20-nm Au film (top of Figure 1) and the bottom region only Si. (c-d) SEM images corresponding to the postirradiation condition for the Au-coated (c) and uncoated (d) regions. Si nanostructures are evidenced only in the region where Au was deposited noting that in (b) XPS Au-4f spectra are absent.
Mentions: Figure 1a shows the spatial profile along a horizontal line to the sample surface with XPS core level peaks of Au 4f and Si 2p. The postirradiation data shown in Figure 1b and corresponding ex situ SEM images (Figure 1c,d) show the effect of the Au coating. An examination of the XPS spectrum in Figure 1b shows no sign of Au, yet the SEM images show nanopatterning only on the region where the Au was deposited. In that region, nanostructures with a diameter of roughly 11-14 nm were formed. Figure 2 shows a magnified image of the silicon dots after the irradiation process. To understand how the gold film affected the nanostructure formation, in situ XPS and LEISS were performed during the irradiation process on another sample fully coated with 10-nm gold. It should be noted here that while XPS is capable of probing the top 1-5 nm of the surface, LEISS probes only the first layer [11,12].

Bottom Line: Structures of 11- to 14-nm Si nanodots are formed with normal incidence low-energy Ar ions of 200 eV and fluences above 2 × 1017 cm-2.In situ surface characterization during ion irradiation elucidates early stage ion mixing migration mechanism for nanodot self-organization.In particular, the evolution from gold film islands to the formation of ion-induced metastable gold silicide followed by pure Si nanodots formed with no need for impurity seeding.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Materials Engineering, Purdue University, West Lafayette, IN 47907, USA. oelatwan@purdue.edu.

ABSTRACT
Ion beam sputtering of ultrathin film Au coatings used as a physical catalyst for self-organization of Si nanostructures has been achieved by tuning the incident particle energy. This approach holds promise as a scalable nanomanufacturing parallel processing alternative to candidate nanolithography techniques. Structures of 11- to 14-nm Si nanodots are formed with normal incidence low-energy Ar ions of 200 eV and fluences above 2 × 1017 cm-2. In situ surface characterization during ion irradiation elucidates early stage ion mixing migration mechanism for nanodot self-organization. In particular, the evolution from gold film islands to the formation of ion-induced metastable gold silicide followed by pure Si nanodots formed with no need for impurity seeding.

No MeSH data available.


Related in: MedlinePlus