Ion-Induced Nanoscale Ripple Patterns on Si Surfaces: Theory and Experiment

Keller, Adrian; Facsko, Stefan

doi:10.3390/ma3104811

Cited by 105 publications

(57 citation statements)

References 110 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We calculated a value for the exponent m of 0.65 ± 0.15 for TiO 2 , which is above the value of m = 0.3 expected from the theory for ion-induced surface self-diffusion. However, the discrepancy can be explained by considering redeposition processes during the sputter process, which lead to a coarsening of the ripple wavelength over irradiation time [24,25]. For our Si reference sample set we obtained an exponent m of 0.5 ± 0.05 (see supplementary information), which is well in agreement with experimental data already published [26], obtained from irradiation with argon ions.…”

Section: Structural Characterizationsupporting

confidence: 81%

Protein Adsorption on Nano-scaled, Rippled TiO2 and Si Surfaces

et al. 2012

View full text Add to dashboard Cite

We synthesized nano-scaled periodic ripple patterns on silicon and titanium dioxide (TiO2) surfaces by xenon ion irradiation, and performed adsorption experiments with human plasma fibrinogen (HPF) on such surfaces as a function of the ripple wavelength. Atomic force microscopy showed the adsorption of HPF in mostly globular conformation on crystalline and amorphous flat Si surfaces as well as on nano-structured Si with long ripple wavelengths. For short ripple wavelengths the proteins seem to adsorb in a stretched formation and align across or along the ripples. In contrast to that, the proteins adsorb in a globular assembly on flat and long-wavelength rippled TiO2, but no adsorbed proteins could be observed on TiO2 with short ripple wavelengths due to a decrease of the adsorption energy caused by surface curvature. Consequently, the adsorption behavior of HPF can be tuned on biomedically interesting materials by introducing a nano-sized morphology while not modifying the stoichiometry/chemistry.

show abstract

Section: Structural Characterizationsupporting

confidence: 81%

Protein Adsorption on Nano-scaled, Rippled TiO2 and Si Surfaces

et al. 2012

View full text Add to dashboard Cite

show abstract

“…[5][6][7][8][9][10][11][12][13][14] In particular, metallic surfactants like Fe and Mo induce pronounced dot and ripple patterns on Si substrates even during normal and near normal ion incidence sputter erosion. 2,8,9,[11][12][13] In the absence of co-deposition of foreign atoms and for normal and near normal ion incidence, even for incidence angles up to 50…”

Section: Introductionmentioning

confidence: 99%

Sharp transition from ripple patterns to a flat surface for ion beam erosion of Si with simultaneous co-deposition of iron

2012

View full text Add to dashboard Cite

We investigate pattern formation on Si by sputter erosion under simultaneous co-deposition of Fe atoms, both at off-normal incidence, as function of the Fe surface coverage. The patterns obtained for 5 keV Xe ion irradiation at 30° incidence angle are analyzed with atomic force microscopy. Rutherford backscattering spectroscopy of the local steady state Fe content of the Fe-Si surface layer allows a quantitative correlation between pattern type and Fe coverage. With increasing Fe coverage the patterns change, starting from a flat surface at low coverage (< 2×1015 Fe/cm2) over dot patterns (2-8×1015 Fe/cm2), ripples patterns (8-17×1015 Fe/cm2), pill bug structures (1.8×1016 Fe/cm2) and a rather flat surface with randomly distributed weak pits at high Fe coverage (>1.8×1016 Fe/cm2). Our results confirm the observations by Macko for 2 keV Kr ion irradiation of Si with Fe co-deposition. In particular, we also find a sharp transition from pronounced ripple patterns with large amplitude (rms roughness ∼ 18 nm) to a rather flat surface (rms roughness ∼ 0.5 nm). Within this transition regime, we also observe the formation of pill bug structures, i.e. individual small hillocks with a rippled structure on an otherwise rather flat surface. The transition occurs within a very narrow regime of the steady state Fe surface coverage between 1.7 and 1.8×1016 Fe/cm2, where the composition of the mixed Fe-Si surface layer of about 10 nm thickness reaches the stoichiometry of FeSi2. Phase separation towards amorphous iron silicide is assumed as the major contribution for the pattern formation at lower Fe coverage and the sharp transition from ripple patterns to a flat surface

show abstract

“…Both effects are known to contribute to roughening and to the formation of spatially periodic ripple patterns. Pattern formation due to curvaturedependent ion beam erosion can be described by the linear theory of Bradley-Harper (BH) [1] and related theories with non-linear extensions [2][3][4][5][6][7][8]. In the BH model, curvature-dependent sputtering depends linearly on the locally deposited energy approximated by Sigmund's ellipsoidal energy deposition [9].…”

Section: Introductionmentioning

confidence: 99%

Surface instability and pattern formation by ion-induced erosion and mass redistribution

Hofsäß

2013

Appl. Phys. A

View full text Add to dashboard Cite

The contribution of curvature dependent sputtering and mass redistribution to ion-induced self-organized formation of periodic surface nanopatterns is revisited. Ion incidence angle-dependent curvature coefficients and ripple wavelengths are calculated from 3-dimensional collision cascade data obtained from binary collision Monte Carlo simulations. Significant modifications concerning mass redistribution compared to the model of Carter and Vishnyakov and also models based on crater functions are introduced. Furthermore, I find that curvature-dependent erosion is the dominating contribution to pattern formation, except for very low-energy irradiation of a light matrix with heavy ions. The major modifications regarding mass redistribution and ion-induced viscous flow are related to the ion incidence angle-dependent thickness of the irradiated layer. A smaller modification concerns the relaxation of inward-directed mass redistribution. Ioninduced viscous flow in the surface layer also depends on the layer thickness and is thus strongly angle dependent. Simulation results are presented and compared to a variety of published experimental results. The simulations show that in most cases curvature-dependent erosion is the dominant contribution to surface instability and ripple pattern formation and also determines the pattern orientation transition. The simulations predict the occurrence of perpendicular ripple patterns at larger ion incidence angles, in agreement with experimental observations. Mass redistribution causes stabilization of the surface at near-normal ion incidence angles and dominates pattern formation only at very low ion energies.

show abstract

Ion-Induced Nanoscale Ripple Patterns on Si Surfaces: Theory and Experiment

Cited by 105 publications

References 110 publications

Protein Adsorption on Nano-scaled, Rippled TiO2 and Si Surfaces

Protein Adsorption on Nano-scaled, Rippled TiO2 and Si Surfaces

Sharp transition from ripple patterns to a flat surface for ion beam erosion of Si with simultaneous co-deposition of iron

Surface instability and pattern formation by ion-induced erosion and mass redistribution

Contact Info

Product

Resources

About