Fractal dimension of thin film surfaces of gold sputter deposited on mica: a scanning tunneling microscopic study

Nogués, J.; Costa, Jerome; Rao, K. V. S. Rama

doi:10.1016/0378-4371(92)90019-m

Cited by 22 publications

(12 citation statements)

References 9 publications

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“…6(b), the normalized {111} reflections for both the Au:1 and Au:2 surfaces are overlayed. Individual fitting of the diffraction peaks was carried out by fitting the sample-dependent variables (angle position, intensity and line broadening) to the experimental diffraction profile using a Marquardt nonlinear least-squares algorithm [11]. The Au:1 exhibits a higher relative intensity than the Au:2 surface by a factor of ∼1.5.…”

Section: Resultsmentioning

confidence: 99%

Advancing atomic nanolithography: cold atomic Cs beam exposure of alkanethiol self-assembled monolayers

O’Dwyer

Lesegno

Weiner

et al. 2005

J. Phys.: Conf. Ser.

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Abstract. We report the results of a study into the quality of functionalized surfaces for nanolithographic imaging. Self-assembled monolayer (SAM) coverage, subsequent post-etch pattern definition and minimum feature size all depend on the quality of the Au substrate used in atomic nanolithographic experiments. We find sputtered Au substrates yield much smoother surfaces and a higher density of {111} oriented grains than evaporated Au surfaces. A detailed study of the self-assembly mechanism using molecular resolution AFM and STM has shown that the monolayer is composed of domains with sizes typically of 5-25 nm, and multiple molecular domains can exist within one Au grain. Exposure of the SAM to an optically-cooled atomic Cs beam traversing a two-dimensional array of submicron material masks ans also standing wave optical masks allowed determination of the minimum average Cs dose (2 Cs atoms per SAM molecule) and the realization of < 50 nm structures. The SAM monolayer contains many non-uniformities such as pin-holes, domain boundaries and monoatomic depressions which are present in the Au surface prior to SAM adsorption. These imperfections limit the use of alkanethiols as a resist in atomic nanolithography experiments. These studies have allowed us to realize an Atom Pencil suitable for deposition of precision quantities of material at the micro-and nanoscale to an active surface.

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Section: Resultsmentioning

confidence: 99%

Advancing atomic nanolithography: cold atomic Cs beam exposure of alkanethiol self-assembled monolayers

O’Dwyer

Lesegno

Weiner

et al. 2005

J. Phys.: Conf. Ser.

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“…The overall surface topography of the Au:1 surface is relatively homogeneous, whereas for Au:2 surfaces, the grain structures responsible for the roughness are clearly visible. The obtained fractal dimension characterizes the influences of the granular structure on the roughness of the respective surface [32]. For Au:1 substares, the value of D approaches the value 2, indicating a smooth, nearly ideal 2-dimensional surface [32].…”

Section: A Comparison Of Sputtered and Evaporated Au Surfacesmentioning

confidence: 99%

“…Such an approach allows us to correlate the measured fractal dimension of the STM measurements to a fractal dimension which characterizes the roughness of the surface. The fractal dimension, D, of the film surfaces has been analyzed using a modified "slit island" technique [32]. This method is based on the perimeter-area relationship developed by Mandlebrot [33,34].…”

Section: A Comparison Of Sputtered and Evaporated Au Surfacesmentioning

confidence: 99%

“…The obtained fractal dimension characterizes the influences of the granular structure on the roughness of the respective surface [32]. For Au:1 substares, the value of D approaches the value 2, indicating a smooth, nearly ideal 2-dimensional surface [32]. The grain structures align themselves parallel to the substrate orientation to produce a smoother surface.…”

Section: A Comparison Of Sputtered and Evaporated Au Surfacesmentioning

confidence: 99%

“…4b, the normalized {111} reflections for both the Au:1 and Au:2 surfaces are overlayed. Individual fitting of the diffraction peaks was carried out by fitting the sampledependent variables (angle position, intensity and line broadening) to the experimental diffraction profile using a Marquardt nonlinear least-squares algorithm [32]. It is observed that the Au:1 exhibits a higher relative intensity than the Au:2 surface by a factor of ≃ 1.5.…”

Section: Crystal Orientation and Grain Densitymentioning

confidence: 99%

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Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

O’Dwyer

Gay

Lesegno

et al. 2005

Journal of Applied Physics

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We report the results of a study into the factors controlling the quality of nanolithographic imaging. Self-assembled monolayer (SAM) coverage, subsequent postetch pattern definition, and minimum feature size all depend on the quality of the Au substrate used in material mask atomic nanolithographic experiments. We find that sputtered Au substrates yield much smoother surfaces and a higher density of {111}-oriented grains than evaporated Au surfaces. Phase imaging with an atomic force microscope shows that the quality and percentage coverage of SAM adsorption are much greater for sputtered Au surfaces. Exposure of the self-assembled monolayer to an optically cooled atomic Cs beam traversing a two-dimensional array of submicron material masks mounted a few microns above the self-assembled monolayer surface allowed determination of the minimum average Cs dose (2 Cs atoms per self-assembled monolayer molecule) to write the monolayer. Suitable wet etching, with etch rates of 2.2 nm min-1, results in optimized pattern definition. Utilizing these optimizations, material mask features as small as 230 nm in diameter with a fractional depth gradient of 0.820 nm were realized

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Fractal Dimension of Thin-film Surfaces Obtained by Fourier Spectral Analysis

Zahn

Zösch

1997

Surf. Interface Anal.

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The applicability of models based on fractal geometry to characterize thin‐film surfaces was investigated. The fractal geometry of sputtered chromium nitride and silicon nitride thin‐film surfaces was described using Fourier spectral analysis of profiles from scanning tunnelling microscopy images and atomic force microscopy images. The CrNx and SiNx coatings were deposited on silicon wafers using reactive magnetron sputtering and varying the gas pressure. The columnar structure of the amorphous silicon nitride varied with deposition, similar to the structure of the polycrystalline chromium nitride films. The fractal dimension decreases with increasing pressure. Films with fine columnar structures are characterized by a larger fractal dimension than films with coarse columnar structures.© 1997 John Wiley & Sons, Ltd.

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Fractal dimension of thin film surfaces of gold sputter deposited on mica: a scanning tunneling microscopic study

Cited by 22 publications

References 9 publications

Advancing atomic nanolithography: cold atomic Cs beam exposure of alkanethiol self-assembled monolayers

Advancing atomic nanolithography: cold atomic Cs beam exposure of alkanethiol self-assembled monolayers

Writing self-assembled monolayers with Cs: Optimization of atomic nanolithography imaging using self-assembled monolayers on gold substrates

Fractal Dimension of Thin-film Surfaces Obtained by Fourier Spectral Analysis

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