Ion beam erosion can be used as a process for achieving surface smoothing at microscopic length s... more Ion beam erosion can be used as a process for achieving surface smoothing at microscopic length scales and for the preparation of ultrasmooth surfaces, as an alternative to nanostructuring of various surfaces via self-organization. This requires that in the evolution of the surface topography different relaxation mechanisms dominate over the roughening, and smoothing of initially rough surfaces can occur. This contribution focuses on the basic mechanisms as well as potential applications of surface smoothing using low energy ion beams. In the first part, the fundamentals for the smoothing of III/V semiconductors, Si and quartz glass surfaces using low energy ion beams (ion energy: ≤2000 eV) are reviewed using examples. The topography evolution of these surfaces with respect to different process parameters (ion energy, ion incidence angle, erosion time, sample rotation) has been investigated. On the basis of the time evolution of different roughness parameters, the relevant surface relaxation mechanisms responsible for surface smoothing are discussed. In this context, physical constraints as regards the effectiveness of surface smoothing by direct ion bombardment will also be addressed and furthermore ion beam assisted smoothing techniques are introduced. In the second application-orientated part, recent technological developments related to ion beam assisted smoothing of optically relevant surfaces are summarized. It will be demonstrated that smoothing by direct ion bombardment in combination with the use of sacrificial smoothing layers and the utilization of appropriate broad beam ion sources enables the polishing of various technologically important surfaces down to 0.1 nm root mean square roughness level, showing great promise for large area surface processing. Specific examples are given for ion beam smoothing of different optical surfaces, especially for substrates used for advanced optical applications (e.g., in x-ray optics and components for extreme ultraviolet lithography).
ABSTRACT Ripple formation and smoothing of pre-patterned fused silica surfaces by low-energy ion ... more ABSTRACT Ripple formation and smoothing of pre-patterned fused silica surfaces by low-energy ion beam erosion have been investigated. As pre-pattern ripple surfaces produced by low-energy Ar+ ion beam erosion were used. In addition to the enhanced ripple formation on the pre-patterned surfaces also the smoothing characteristics of surface is changed. Due to the anisotropic surface roughness of the ripple pattern the irradiation direction with respect to the pre-pattern becomes important. It is suggested that all of these effects are related to surface gradient dependent sputtering and therefore it is an important mechanisms also in the low-energy ion beam erosion of fused silica surfaces.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2009
... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record... more ... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (4270). [4] W. Hofmeister, E. Tillmanns and WHBauer, Acta Crystallogr. C 40 (1984), p. 1510. Full Text via CrossRef. ...
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2009
... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record... more ... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (4270). [4] W. Hofmeister, E. Tillmanns and WHBauer, Acta Crystallogr. C 40 (1984), p. 1510. Full Text via CrossRef. ...
... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Rip... more ... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Ripple pattern formation on silicon surfaces by low-energy ion-beam erosion: Experiment and theory B. Ziberi,1 F. Frost,1 Th. ... PHYSICAL REVIEW B 72, 235310 2005 FIG. ...
In this work different ion-beam techniques demonstrate their capability for surface-roughness red... more In this work different ion-beam techniques demonstrate their capability for surface-roughness reduction down to the sub-nanometer scale. In ion beam direct smoothing, favorable characteristics in the development of surface topography are exploited and smoothing with the help of planarization layers is evaluated. Focusing on the common optical substrate materials quartz (fused silica) and silicon, it is shown that a surface-roughness reduction down to the ∼0.1 nm root mean square level can be achieved by optimization and combination of these techniques.
A newly developed laboratory grazing-incidence small-angle X-ray scattering GISAXS system capable... more A newly developed laboratory grazing-incidence small-angle X-ray scattering GISAXS system capable of statistical measurements of surface morphology at the nanometer scale was developed. The potential of the GISAXS system is compared to the AFM technique for a nanopatterned silicon surface produced by ion-beam erosion. The characteristic period of the ion-beam induced ripples and their lateral correlation length were estimated from AFM. Using GISAXS the reciprocal space map of surface morphology was measured and analyzed. The two microfocus X-ray sources emitting radiation at the Cu-Kα and Cr-Kα were used. The lateral periods of ripples obtained by the reciprocal space mapping techniques match the results of real space techniques. The setup has the potential to monitor and control the deposition process and formation of nanostructures with sufficient temporal and spatial resolution.
Low-energy ion-beam sputtering, i.e. the removal of atoms from a surface due to the impact of ene... more Low-energy ion-beam sputtering, i.e. the removal of atoms from a surface due to the impact of energetic ions or atoms, is an inherent part of numerous surface processing techniques. Besides the actual removal of material, this surface erosion process often results in a pronounced alteration of the surface topography. Under certain conditions, sputtering results in the formation of well-ordered patterns. This self-organized pattern formation is related to a surface instability between curvature-dependent sputtering that roughens the surface and smoothing by different surface relaxation mechanisms. If the evolution of surface topography is dominated by relaxation mechanisms, surface smoothing can occur. In this presentation the current status of self-organized pattern formation and surface smoothing by low-energy ion-beam erosion of Si and Ge is summarized. In detail it will be shown that a multitude of patterns as well as ultra-smooth surfaces can develop, particularly on Si surfaces. Additionally, the most important experimental parameters that control these processes are discussed. Finally, examples are given for the application of low-energy ion beams as a novel approach for passive optical device engineering for many advanced optical applications.
This chapter focuses on the self-organized pattern formation by ion beam sputtering. A general de... more This chapter focuses on the self-organized pattern formation by ion beam sputtering. A general description and experimental observations are presented, showing the complexity of the processes involved but also its great potential as patterning technique. The main focus is set on the pattern formation on silicon surfaces. It is shown that several experimental parameters are involved in the topography evolution. Namely, the influence of the ion incidence angle, ion energy, fluence, sample manipulation and substrate temperature is discussed. Additionally, evidence of the importance of iron incorporation in the formation of certain features is presented. The possibility of applying this technique to other materials is illustrated with examples on germanium, compounds semiconductor, silica and crystalline metals.
... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Rip... more ... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Ripple pattern formation on silicon surfaces by low-energy ion-beam erosion: Experiment and theory B. Ziberi,1 F. Frost,1 Th. ... PHYSICAL REVIEW B 72, 235310 2005 FIG. ...
Ion beam erosion can be used as a process for achieving surface smoothing at microscopic length s... more Ion beam erosion can be used as a process for achieving surface smoothing at microscopic length scales and for the preparation of ultrasmooth surfaces, as an alternative to nanostructuring of various surfaces via self-organization. This requires that in the evolution of the surface topography different relaxation mechanisms dominate over the roughening, and smoothing of initially rough surfaces can occur. This contribution focuses on the basic mechanisms as well as potential applications of surface smoothing using low energy ion beams. In the first part, the fundamentals for the smoothing of III/V semiconductors, Si and quartz glass surfaces using low energy ion beams (ion energy: ≤2000 eV) are reviewed using examples. The topography evolution of these surfaces with respect to different process parameters (ion energy, ion incidence angle, erosion time, sample rotation) has been investigated. On the basis of the time evolution of different roughness parameters, the relevant surface relaxation mechanisms responsible for surface smoothing are discussed. In this context, physical constraints as regards the effectiveness of surface smoothing by direct ion bombardment will also be addressed and furthermore ion beam assisted smoothing techniques are introduced. In the second application-orientated part, recent technological developments related to ion beam assisted smoothing of optically relevant surfaces are summarized. It will be demonstrated that smoothing by direct ion bombardment in combination with the use of sacrificial smoothing layers and the utilization of appropriate broad beam ion sources enables the polishing of various technologically important surfaces down to 0.1 nm root mean square roughness level, showing great promise for large area surface processing. Specific examples are given for ion beam smoothing of different optical surfaces, especially for substrates used for advanced optical applications (e.g., in x-ray optics and components for extreme ultraviolet lithography).
ABSTRACT Ripple formation and smoothing of pre-patterned fused silica surfaces by low-energy ion ... more ABSTRACT Ripple formation and smoothing of pre-patterned fused silica surfaces by low-energy ion beam erosion have been investigated. As pre-pattern ripple surfaces produced by low-energy Ar+ ion beam erosion were used. In addition to the enhanced ripple formation on the pre-patterned surfaces also the smoothing characteristics of surface is changed. Due to the anisotropic surface roughness of the ripple pattern the irradiation direction with respect to the pre-pattern becomes important. It is suggested that all of these effects are related to surface gradient dependent sputtering and therefore it is an important mechanisms also in the low-energy ion beam erosion of fused silica surfaces.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2009
... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record... more ... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (4270). [4] W. Hofmeister, E. Tillmanns and WHBauer, Acta Crystallogr. C 40 (1984), p. 1510. Full Text via CrossRef. ...
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2009
... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record... more ... [3] A. Fujishima and K. Honda, Nature 238 (1972), p. 37. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (4270). [4] W. Hofmeister, E. Tillmanns and WHBauer, Acta Crystallogr. C 40 (1984), p. 1510. Full Text via CrossRef. ...
... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Rip... more ... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Ripple pattern formation on silicon surfaces by low-energy ion-beam erosion: Experiment and theory B. Ziberi,1 F. Frost,1 Th. ... PHYSICAL REVIEW B 72, 235310 2005 FIG. ...
In this work different ion-beam techniques demonstrate their capability for surface-roughness red... more In this work different ion-beam techniques demonstrate their capability for surface-roughness reduction down to the sub-nanometer scale. In ion beam direct smoothing, favorable characteristics in the development of surface topography are exploited and smoothing with the help of planarization layers is evaluated. Focusing on the common optical substrate materials quartz (fused silica) and silicon, it is shown that a surface-roughness reduction down to the ∼0.1 nm root mean square level can be achieved by optimization and combination of these techniques.
A newly developed laboratory grazing-incidence small-angle X-ray scattering GISAXS system capable... more A newly developed laboratory grazing-incidence small-angle X-ray scattering GISAXS system capable of statistical measurements of surface morphology at the nanometer scale was developed. The potential of the GISAXS system is compared to the AFM technique for a nanopatterned silicon surface produced by ion-beam erosion. The characteristic period of the ion-beam induced ripples and their lateral correlation length were estimated from AFM. Using GISAXS the reciprocal space map of surface morphology was measured and analyzed. The two microfocus X-ray sources emitting radiation at the Cu-Kα and Cr-Kα were used. The lateral periods of ripples obtained by the reciprocal space mapping techniques match the results of real space techniques. The setup has the potential to monitor and control the deposition process and formation of nanostructures with sufficient temporal and spatial resolution.
Low-energy ion-beam sputtering, i.e. the removal of atoms from a surface due to the impact of ene... more Low-energy ion-beam sputtering, i.e. the removal of atoms from a surface due to the impact of energetic ions or atoms, is an inherent part of numerous surface processing techniques. Besides the actual removal of material, this surface erosion process often results in a pronounced alteration of the surface topography. Under certain conditions, sputtering results in the formation of well-ordered patterns. This self-organized pattern formation is related to a surface instability between curvature-dependent sputtering that roughens the surface and smoothing by different surface relaxation mechanisms. If the evolution of surface topography is dominated by relaxation mechanisms, surface smoothing can occur. In this presentation the current status of self-organized pattern formation and surface smoothing by low-energy ion-beam erosion of Si and Ge is summarized. In detail it will be shown that a multitude of patterns as well as ultra-smooth surfaces can develop, particularly on Si surfaces. Additionally, the most important experimental parameters that control these processes are discussed. Finally, examples are given for the application of low-energy ion beams as a novel approach for passive optical device engineering for many advanced optical applications.
This chapter focuses on the self-organized pattern formation by ion beam sputtering. A general de... more This chapter focuses on the self-organized pattern formation by ion beam sputtering. A general description and experimental observations are presented, showing the complexity of the processes involved but also its great potential as patterning technique. The main focus is set on the pattern formation on silicon surfaces. It is shown that several experimental parameters are involved in the topography evolution. Namely, the influence of the ion incidence angle, ion energy, fluence, sample manipulation and substrate temperature is discussed. Additionally, evidence of the importance of iron incorporation in the formation of certain features is presented. The possibility of applying this technique to other materials is illustrated with examples on germanium, compounds semiconductor, silica and crystalline metals.
... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Rip... more ... F. Frost, B. Ziberi, and B. Rauschenbach (unpublished). PHYSICAL REVIEW B 72, 235310 2005 Ripple pattern formation on silicon surfaces by low-energy ion-beam erosion: Experiment and theory B. Ziberi,1 F. Frost,1 Th. ... PHYSICAL REVIEW B 72, 235310 2005 FIG. ...
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