Plenarvorträge - DPG-Tagungen

Dünne Schichten Mittwoch
DS 15 Oberflächenmodifizierung
Zeit: Mittwoch 16:15–18:00 Raum: HS 32
DS 15.1 Mi 16:15 HS 32
Self-organized pattern formation on Si surfaces by ion beam
erosion — •Bashkim Ziberi, Frank Frost, and Bernd Rauschenbach
— Leibniz-Institut für Oberflächenmodifizierung e. V., Permoserstraße
15, D-04318 Leipzig, Germany
The spontaneous formation of regular structures with nanometer dimensions
(< 100 nm) on semiconductor surfaces originates from selforganisation
processes during ion beam erosion and offers a promising
tool for the fabrication of large-area nanostructured surfaces.
In this study the self-organized pattern formation on Si surfaces during
low-energy Ar + ion beam erosion (ion energy ≤ 2000 eV) under normal
and oblique ion incidence with and without sample rotation was investigated.
It is shown that ordered nanodots are formed at normal ion
incidence for ion energies ≥ 1000 eV and, additionally, for ion energies ≤
2000 eV at oblique ion incidence angles between 70 ◦ and 80 ◦ with respect
to the surface normal. The dots generated under oblique ion incidence
conditions show a remarkable high degree of ordering comparable to dot
patterns on III/V semiconductors. In the case of no sample rotation remarkable
highly ordered ripple patterns can be produced at ion incidence
angles slightly deviating from normal ion incidence.
DS 15.2 Mi 16:30 HS 32
Morphology investigations of ion-eroded SiGe alloy layers —
•Christian Hofer 1 , Stephan Abermann 1 , Christian Teichert 1 ,
Markus Wächter 2 , Thomas Bobek 2 , Heinrich Kurz 2 , Klara
Lyutovich 3 , and Erich Kasper 3 — 1 Department of Physics, University
of Leoben, Austria — 2 Institute of Semiconductor Technology,
RWTH Aachen, Germany — 3 Institute of Semiconductor Engineering,
University of Stuttgart, Germany
The possibility to generate well-ordered nanostructures through ionbombardment
of III-V semiconductor surfaces [1] motivated the investigation
of normal incidence Ar + -ion bombardment on already selforganized
SiGe films [2]. The role of different dislocation densities and
starting morphologies on the subsequent pattern formation was investigated
by high resolution AFM.
Two different energy regimes were found. For ion-energies of 500 eV
and below the surface roughens and craters with a diameter of 70 nm
evolve. At higher energies smoothening mechanisms take place. The influence
of misfit dislocations on the SiGe pattern formation [3] and the
evolution of size and distribution of the nanostructure array depending
on ion-energy are discussed in the framework of current theories of ionbombardment
induced pattern formation.
[1] S. Facsko, et al., Science 285, 1551 (1999); F. Frost, et al., Phys.
Rev. Lett. 85, 4116 (2000).
[2] C. Teichert et al., Thin Solid Films 380, 28 (2000).
[3] C. Hofer et al., Nucl. Instr. and Meth. B, in print.
This work was partly supported by FWF Austria, P14009-TPH.
DS 15.3 Mi 16:45 HS 32
Relaxations- und Kristallisationsprozesse bei der ioneninduzierten
Amorphisierung von In2Au-Filmen — •Paul Ziemann und
Thomas Müller — Abteilung Festkörperphysik, Universität Ulm, D-
89069 Ulm
Ionenbestrahlung bietet die Möglichkeit, ausgehend von polykristallinen
Schichten binärer Legierungen, diese schrittweise zu amorphisieren.
Damit lassen sich Proben mit verschiedenen Anteilen amorpher Phase
präparieren und der Einfluss dieses Anteils auf Relaxationsprozesse und
Kristallisationstemperatur kann untersucht werden. Solche Experimente
wurden an In2Au-Filmen durch Bestrahlung mit 300 keV Ar-Ionen bei
80 K durchgeführt und mit in-situ Widerstandsmessungen kombiniert.
Über diese Ergebnisse wird berichtet.
DS 15.4 Mi 17:00 HS 32
Plastic deformation of amorphous silicon under swift heavy
ion irradiation — •André Hedler 1 , Siegfried Klaumünzer 2 , and
Werner Wesch 1 — 1 Institut für Festkörperphysik, Friedrich-Schiller-
Universität Jena, Max-Wien-Platz 1, 07743 Jena — 2 Hahn-Meitner-
Institut Berlin, Glienicker Str. 100, 14109 Berlin
All the investigated amorphous materials show an anisotropic plastic
deformation under swift heavy ion irradiation (ion hammering). In
the past years this effect has been discussed controversially whereas the
viscoelastic theory by Trinkaus et al. represents a good description for
glasses. However, a verification of the model for amorphous semiconductors
has not been undertaken. With its well-known physical properties Si
seems to be a suitable candidate to be investigated first.
Single-crystalline Si wafers were amorphized by low energy Si ion implantation
and post-irradiated with MeV Au and Xe ions at 77 K and
300 K. For a constant electronic stopping power a linear increase of the
plastic deformation of amorphous Si with increasing ion fluence was observed
at both temperatures and was assigned to corresponding deformation
yields per ion. Our results show for the first time a dependence
of the deformation yield on the electronic stopping power and on the
temperature for amorphous Si and therefore provide a basis to verify the
theory.
DS 15.5 Mi 17:15 HS 32
Elektrischer Transport in epitaktischen, dünnen, ionenbestrahlten
Gold-Filmen — •Gerd Kästle, Thomas Müller, Hans-Gerd
Boyen, Alexander Schröder und Paul Ziemann — Abteilung
Festkörperphysik, Universität Ulm, 89069 Ulm
Der Einfluss der Ionenbestrahlung auf die Temperaturabhängigkeit des
Widerstands epitaktischer, glatter Goldfilme wurde untersucht. Die Experimente
wurden an He- oder Ar-bestrahlten Filmen unterschiedlicher
Dicke durchgeführt, um Oberflächen- und Volumeneffekte zu trennen.
Neben der erwarteten Widerstandserhöhung durch Ionenstrahlinduzierte
Defekte wird im Rahmen einer Size-Effekt Analyse eine starke
Absenkung der Debye-Temperatur beobachtet. Mit zunehmender Bestrahlungsdosis
verhalten sich die Gitterschwingungen der Goldfilme weicher.
Wie bei sehr dünnen Filmen scheint durch die erhöhte Defektkonzentration
das für den Transport relevante Oberflächen- zu Volumenverhältnis
zu steigen, was sich letztlich in der Absenkung der Debye-
Temperatur bemerkbar macht.
DS 15.6 Mi 17:30 HS 32
Influence of gas pressure and substrate temperature on diffusion
process of carbon/nitrogen in 304 AISI using PIII — •A. M. Abd
El-Rahmann 1,2 , F. M. El-Hossary 1 , N. Z. Negm 1 , F. Prokert 2 ,
E. Richter 2 , and W. Möller 2 — 1 Physics Department, Faculty of Science,
South Valley University, Sohag Branch, Sohag, Egypt — 2 Institute
of Ion Beam Physics and Material Research, Centrum Rossendorf, Dresden,
Germany
Plasma immersion ion implementation (PIII) has been used to modify
the surface properties of 304 austenitic stainless steel (AISI). The influence
of the working gas pressure in a range from 0.2 up to 1.0 Pa and
the substrate temperature from 300 ◦ C to 500 ◦ C on the microstructure,
nitrogen/carbon concentration depth profile and surface microheadness
were investigated at fixed gas composition (25 % C2H2, 75 % N2), 350 W
rf plasma power and -30 kV negative biased potential. The experimental
results show that the substrate temperature and the diffusion process of
nitrogen and carbon is affected by the increase of gas pressure. The thickness
of the modified layer is more than 30 µm. The results provide recent
diffusion rate is about 3.4 × 10 −1 µm 2 /sec with a surface microhardness
of about 1880 kg/mm 2 .
DS 15.7 Mi 17:45 HS 32
Improvement in adhesion of noble metals on polymer surfaces
modified with low energy ions — •Jurgita Zekonyte, Sebastian
Wille, Ulrich Schürmann, Vladimir Zaporojtchenko,
and Franz Faupel — Lehrstuhl für Materialverbunde, Technische
Fakult ¨ *t der CAU, Kaiserstr. 2, 24143 Kiel
The influence of ion-beam treatment with low energy Ar+, N+ and
O+ ions at ion fluences of 10E12 - 10E17 ions/cm2 on the early stage
of metal/polymer interface formation, and the adhesion strength of Cu
and Au on PS and PP was investigated. The ion bombardment changed
the polymer surface chemical structure introducing new oxygen and/or
nitrogen containing functional groups, that influenced metal/polymer interaction.
Metals of low reactivity such as Cu or Au formed 3D-clusters
during the vapour phase deposition. In the case of PS and PP the incomplete
condensation was observed on the untreated surfaces at RT.
The ion bombardment created a defined concentration of defects that
acted as a new adsorption sites on polymer surfaces, leading to an increase
in the cluster density with ion fluence, and the enhancement in the