Plenarvorträge - DPG-Tagungen

Dünne Schichten Dienstag
parameters the relevant surface relaxation mechanisms (ion-induced viscous
flow, surface erosion smoothing) responsible for surface smoothing
have been discussed. Additionally, it is shown that surface smoothing by
ion-induced viscous flow can operate on different length scales.
DS 22.16 Di 14:30 Poster B
Non-conventional plasma sheath diagnostics for thin film
deposition — •Holger Kersten 1 , Ruben Wiese 2 , and Marcel
Haehnel 2 — 1 INP Greifswald, F.-L.-Jahn-Str.19, D-17489 Greifswald
— 2 University of Greifswald, Department of Physics, Domstr.10a,
D-17487 Greifswald
Plasma and sheath diagnostics of sources used in thin film deposition
is an essential issue for optimization and improvement of the related processes
(sputtering, PECVD etc.). Often, complicated and expensive diagnostic
methods (as mass spectrometry, spectroscopy, Langmuir probes
etc.) have to be employed.
However, in certain cases these methods may be completed by relatively
simple methods which can reveal information on the densities,
energies and fluxes of the involved species, too. Such non-conventional
methods are : energy flux measurements by thermal probes, analytical
sheath photometry, and sheath diagnostics by charged micro-particles.
These procedures will be reviewed and their advantages, but also their
disadvantages and limits will be summarized.
DS 22.17 Di 14:30 Poster B
Reactive plasma jet etching of Si - Gas flow models and
mass spectrometry — •Thomas Arnold 1 , Sergey Grabovski 2 ,
Axel Schindler 1 , and Hans-Erich Wagner 2 — 1 Leibniz-Institut
für Oberflächenmodifizierung e.V. Leipzig — 2 Ernst-Moritz-Arndt-
Universität Greifswald
A low pressure microwave driven reactive Ar/SF6 plasma jet used for
high rate etching of Si and SiO2 is investigated by appearance potential
mass spectrometry (APMS) and electron attachment mass spectrometry
(EAMS). Spatially resolved measurements of neutral radicals and stable
products in the active and passive plasma region have been accomplished.
The concentration of atomic fluorine was determined for different process
parameters such as gas mixture and microwave power. The experimental
results are compared to a previously built gas phase reaction kinetics
model, which considers the formation of reactive F and F− radicals and
the production of SFx and SF− x by electron impact, electron attachment
and significant reverse processes. Two-dimensional computational fluid
dynamics simulations of a simplified plasma jet model are compared to
the experimentally obtained species concentrations on a substrate surface.
Additionally, results of surface analysis of etched Si substrates by
means of XPS and optical profilers are presented.
DS 22.18 Di 14:30 Poster B
Single domain growth of C60 on modified InP(001) and chemical
passivation of the molecular structure — •Maxim Eremtchenko,
Stefan Döring, Ruslan Temirov, and Juergen A. Schaefer —
Institut für Physik und Zentrum für Mikro- und Nanotechnologien, Technische
Universität Ilmenau, P.O. Box 100565, 98684 Ilmenau, Germany
Fullerenes and its functionalisation are very promising in nanoscale
fabrication. Its performance is often limited by structural inhomogenities
and chemical instability. Recently, we reported upon single domain
growth of C60 on InP(001), which is technologically very promising. In
this contribution growth of C60 on InP(001) covered with indium clusters,
the most prominent defect on InP was investigated. Single domain
growth is still registered by LEED and STM. The reaction of atomic hydrogen
with the single domain of C60 was studied using HREELS. The
cages are easily cracked by hydrogen and hydrocarbons are formed. This
layer is stable against further reaction with atomic hydrogen, oxygen or
air. It seems that this technique of passivation can be applied for the
protection of various molecular structures in technological processes.
DS 22.19 Di 14:30 Poster B
Growth of ITO thin films by ion beam assisted deposition —
•Karola Thiele 1 , Jörg Hoffmann 2 , Sibylle Sievers 1 , and Herbert
C. Freyhardt 1,2 — 1 Institut für Materialphysik, Tammannstr.1,
37077 Göttingen — 2 Zentrum für Funktionswerkstoffe, Windausweg 2,
37073 Göttingen
Indium Tin Oxide (ITO), a doped, wide-band-gap highly degenerated
oxide semiconductor exhibits high transmittance in the visible region
and high electrical conductivity. Therefore, ITO thin films are widely
used as transparent conducting electrodes for a variety of electro/optical
devices. For many applications on temperature sensitive substrates, deposition
at room temperature is desired. Furthermore, highly textured
ITO films might be useful as an electrically conductive buffer layer for
HTS applications.
Biaxially aligned ITO thin films were prepared by an Ion-Beam Assisted
Deposition (IBAD) process at low temperatures. The influence of
various deposition parameters on the growth is discussed as well as the
microstructure evolution, mechanisms of texture development and electrical
properties.
The quality of IBAD-ITO as a highly transparent and highly conductive
material has been demonstrated and the suitability as a buffer layer
for high-current carrying YBCO thin films has been proved.
DS 22.20 Di 14:30 Poster B
Interface roughness of laser deposited Fe/MgO multilayers
— •Andreas Meschede 1 , Christian Fuhse 2 , and Hans-Ulrich
Krebs 1 — 1 Institut für Materialphysik, Universität Göttingen,
Tammanstrasse 1, 37077 Göttingen — 2 Institut für Röntgenphysik,
Universität Göttingen, Geiststrasse 11, 37073 Göttingen
Metal/MgO multilayers with double layer periods in the nanometer
range were deposited by pulsed laser deposition (PLD) in ultra high vacuum
and in an inert gas atmosphere (Ar). The interface roughness of
less than 0.5 nm mainly depends on the bilayer thickness and increases
for ultrathin films, but only slightly depends on the number of bilayers.
To understand the important mechanisms of roughening und smoothing
during the deposition of multilayers, Fe-MgO bilayers were produced
and characterized by x-ray reflectivity. That shows that the MgO-Layer
smooths the rough Fe-surface and so avoids a cumulative accreation of
the interface roughness with increasing number of bilayers. The obtained
interface roughness also strongly depends on the gas pressure and thus
on the kinetic energies of the deposited particles, which will be discussed.
DS 22.21 Di 14:30 Poster B
Gasdruckabhängige Phasenbildung beim Laser-Carburisieren
von Eisen — M. Kahle, E. Carpene und •P. Schaaf — Universität
Göttingen, Zweites Physikalisches Institut, Tammannstrasse 1, D-37077
Göttingen.
Das Laser-Carburisieren - hier die gepulste Laserbestrahlung in
Methan-Atmosphäre - ist ein effizientes Verfahren zum Kohlenstoffeintrag
in die Oberfläche von verschiedenen Werkstoffen [1,2]. Für
reines Eisen hängt die Phasenbildung beim Laser-Carbusieren sehr vom
Methan-Gasdruck ab. Von amorphen Kohlenstoffschichten über die
hexagonale ε-Phase zur θ-Phase (Zementit) können mit ansteigendem
Druck fast alle Phasen gebildet werden. Obwohl das Eisen-Kohlenstoff-
System eine sehr wichtige Rolle für die Anwendung moderner Werkstoffe
spielt, ist die hexagonale ε-Phase noch relativ unbekannt, da sie bisher
nicht als reine oder massive Phase hergestellt werden konnte. Die
Phasen- und Strukturbildung, sowie die resultierenden Eigenschaften
der Schichten werden in Abhängigkeit von der Laserbehandlung bei
verschiedenen Gasdrücken von 0.1 bis 10 bar diskutiert [2].
[1] E. Carpene and P. Schaaf. Appl. Phys. Lett. 80 (2002) 891.
[2] M. Kahle, E. Carpene, and P. Schaaf. Phys. Rev. B in preparation.
DS 22.22 Di 14:30 Poster B
Magnetic properties and crystallinity of NiMn / FeNi(CoFe)
bi-layer systems with different seed layers — •Stefka
Groudeva-Zotova 1 , Reiner Kaltofen 1 , Dieter Elefant 1 ,
Volker Hoffmann 1 , Juergen Thomas 1 , Claus Schneider 2 ,
Wolfgang Michalke 3 , and Roland Mattheis 3 — 1 Leibniz
Institut IFW-Dresden, Helmholtzstrasse 20, D-01069 Dresden —
2 IFF-Forschungszentrum Juelich — 3 IPHT Jena, Winzerlaerstr. 10,
D-07745 Jena
This work presents an investigation of the influence of the seed layer on
the structural and magnetic characteristics of AFM/FM systems 30nm
NiMn / 4nm FeNi(CoFe) deposited by dc and rf magnetron sputtering of
alloy targets. We compare bi-layers deposited on Ta, Cr and permalloy
seed layers in different combinations and with variable thickness. The asgrown
and the field-annealed and -cooled samples are characterised by
GDOS depth-profile analysis for the film composition, by XRD and TEM
for the crystalline structure and by MOKE and AGM measurements for
the magnetic characteristics. A special accelerated post-deposition annealing
and field-cooling procedure is used for the achieving a stable AFM
state in the NiMn film and for generating an uni-directional anysotropy in
the bi-layer AFM/FM system. It was found that the use of different seed