Plenarvorträge - DPG-Tagungen

Dünne Schichten Montag
We studied the structural properties of epitaxial, thin film and low-
Sr-doped lanthanum-manganites, grown on a SrTiO3(001) substrate, as
function of thickness by means of X-ray diffraction. The observed structure
of these thin film manganites differ from bulk materials because of
the presence of strain due to the lattice mismatch between substrate and
film. Dependent on film thickness and on the chosen Bragg-peak the observed
intensity distribution resembles something between a periodically
modulated or a twinned structure. By assuming a nearly periodic array
of twin domains we found by statistical calculation a good agreement of
the model with the measured data.
DS 9.3 Mo 15:45 HS 32
Structure and thickness-dependant lattice parameters of ultrathin
epitaxial Pr2O3 films on Si(001) studied by SR-GIXRD —
•Thomas Schroeder 1 , Tien Lin Lee 1 , Laure Libralesso 1 , Jörg
Zegenhagen 1 , Peter Zaumseil 2 , Christian Wenger 2 , and Hans
Joachim Müssig 2 — 1 E.S.R.F., Beamline ID 32, 6, Rue Jules Horowitz,
38043 Grenoble, France — 2 IHP, Im Technologiepark 25, 15236 Frankfurt
(Oder)
Heteroepitaxial Pr2O3 films on Si(001) show promising results for applications
as high-K dielectrics in future silicon-based microelectronics
devices. To solve the epilayer structure and monitor the evolution of
the lattice parameters over the technologically important thickness range
from 1 to 10 nm, a Synchrotron-grazing incidence X-ray diffraction (SR-
GIXRD) study was performed. The oxide film structure is characterized
by the growth of the cubic Pr2O3 phase (Ia3) with its rectangular (101)
plane on the Si(001) substrate. The resulting two orthogonal rotation
domains of the oxide layer are identified by the four-fold symmetry of
the oxide reflections. The azimuthal orientation of these oxide domains
is determined by measuring the oxide in-plane reflections. These in-plane
measurements together with theta - 2theta scans allow to monitor the
evolution of the oxide unit cell lattice parameters as a function of film
thickness. The transition from almost perfect pseudomorphism to bulk
values is detected from 1 to 10 nm film thickness. The intensity analysis
of the oxide reflections points to a change in the structure factor of oxide
films thinner than 4 nm, probably due to silicate formation at the oxide
/ Si interface.
DS 9.4 Mo 16:00 HS 32
Investigations of Pr2O3 growth modes on 4H-SiC(0001) Surfaces
— •Andriy Goryachko 1 , Guido Beuckert 1 , Peter Zaumseil
2 , Guenter Wagner 3 , and Dieter Schmeisser 1 — 1 Department
for Applied Physics / Sensorics, BTU Cottbus, Universitaetsplatz 3-4,
D-03046 Cottbus, Germany — 2 IHP, Im Technologiepark 25, D-15236
Frankfurt (Oder), Germany — 3 IKZ, Max Born Str. 2, D-12489 Berlin,
Germany
The SiC is suited especially well for high power and high voltage semiconductor
devices. In order to increase the reliability against electrical
breakdown of metal-insulator-semiconductor (MIS) structures, one needs
to use the insulator with possibly higher dielectric constant. Pr2O3 is
shown to posses a much higher dielectric constant (equals 30) than traditionally
used SiO2. Therefore, Pr2O3/SiC is an excellent material combination
for high voltage MIS devices. The 4H-SiC(0001) substrates are
characterised with scanning tunneling microscopy, while the Pr2O3 surface
- with atomic force microscopy technique. We show distinct growth
modes of Pr2O3 film, such as 3D and layer by layer growth. The crystalline
structure and film thickness are determined by X-ray diffraction
and its chemical composition by X-ray photoelectron spectroscopy. The
Pr2O3 film characteristics are optimised for high-quality MIS structures
in terms of lateral uniformity, low interface states density and leakage
current, as well as physical integrity.
DS 9.5 Mo 16:15 HS 32
Mainfold nonosized metallic composites preparation and theoretical
simulations. — •Witold Kandulski 1,2 and Adam Kosiorek
1,2 — 1 CAESAR research center, Dept. Nanoparticle Technology,
Ludwig-Erhard-Allee 2, 53175 Bonn, Germany — 2 Poznan University of
Technology, ul. Nieszawska 13a, 60-965 Poznan, Poland
Nanosphere lithography is a known method for creating ordered metallic
nanostructures. We present a modification of this inexpensive and
varied full technique, which extends the possibilities of creating different
morphologies. Computer simulations were used to determine geometric
configurations of the metal deposition system for creating various
structures. We will show some examples of bimetallic nanosized periodicoriented
large areas of nanostructures. Very good correlations between
the predicted simulation and experimental results were achieved. An additional
goal was the prevention of magnetic particles from oxidation.
Presented arrays of nanostructures have interesting magnetic and optical
properties due to complex geometry, different to previously investigated
spherical shapes which are obtainable by standard geometric configuration.
The possible application will be also discussed.
DS 9.6 Mo 16:30 HS 32
Examination of diamond seed-layers on Ir/ SrTiO3 using Scanning
Electron Microscopy and Auger Electron Spectroscopy —
•P Bernhard 1 , Ch. Ziethen 1 , M. Schreck 2 , S. Gsell 2 , H. Karl 2 ,
G. Schaefer 3 und S. Schoenhense 1 — 1 University of Mainz, D-55099
Mainz — 2 University of Augsburg, D-86135 Augsburg — 3 OMICRON
Nanotechnology GmbH, D-65232 Taunusstein
The growth of diamond films of macroscopic dimensions without grain
boundaries (quasi single crystalline) is greatly influenced by the characteristics
of the diamond seed-layers. These diamond seed-layers grown on
top of an Ir/ SrTiO3 sample using a BEN (Bias Enhanced Nucleation)
process [1] have been analysed using a UHV SEM and a small spot AES
based on a Gemini column.
A peculiarity of this nucleation process is the accumulation of the
diamond nuclei in clear bounded domains with negligible nucleation outside.
In this work we focussed our interest on the determination of the
carbon-layer thickness inside and outside the domains by measuring the
attenuation of the iridium Auger lines. For the calculation the Auger
electron inelastic mean free path in diamond was used.
After Focused Ion Beam structuring of the sample we also determined
the layer thickness of a carbon precursor [2], using the same technique
of SEM/ AES and we examined the contribution of subplantation to the
growth of the diamond layer.
References [1] M. Schreck et al., Apl. Phys. Lett. 78 (2001) 192 [2] Th.
Bauer et al., Diamond and Rel. Mat., 11 (2002) 493
DS 9.7 Mo 16:45 HS 32
In situ Prozessanalytik mit Hilfe der Ramanstreuung und der
spektroskopischen Ellipsometrie — •M. Schubert 1 , N. Ashkenov
1 , C. Bundesmann 1 , M. Lorenz 1 , M. Grundmann 1 , E. Schubert
2 , H. Neumann 2 , B. Rauschenbach 2 , A. Braun 3 und G. Lippold
3 — 1 Fakultät für Physik und Geowissenschaften, Institut für Experimentelle
Physik II, Universität Leipzig, Linnéstraße 5, 04103 Leipzig
— 2 Institut für Oberflächenmodifizierung Leipzig e.V., 04303 Leipzig —
3 Solarion GmbH, Photovoltaik, 04288 Leipzig
Mit Hilfe der in-situ Ramanstreuung und der spektroskopischen in-situ
Ellipsometrie gelingt die zerstörungsfreie, berührungslose und schnelle
Bestimmung von optischen und strukturellen Dünnschicht-Eigenschaften
während des Dünnschichtwachstums. Erfolgt die Messung und Analyse
schnell genug, können die gewonnenen Informationen zur automatischen
Steuerung des laufenden Prozesses in vorgegebenen Parameterbereichen,
und damit zur Langzeitstabilitat von Qualtitätsmerkmalen
verwendet werden. Wir berichten über Anwendungen auf das Wachstum
von CuInSe2-Solarzellenabsorberschichten, ZnO-Dünnschichten, und
Mo-Si Röntgenreflexionsschichstrukturen.
DS 9.8 Mo 17:00 HS 32
Impact of design parameters of coupled parallel beam X-ray
mirrors and channel cut monochromators on divergence, beam
width and monochromacy — •T. Holz 1 , D. Korytar 2 , and T.
Böttger 3 — 1 AXO DRESDEN GmbH, Siegfried-Rädel-Str. 31, D-
01809 Heidenau — 2 Institute of Electrical Engineering, DTDS, Vrbovska
110, SK-92101 Piestany, Slowakia — 3 Fraunhofer Institute for Material
and Beam Technology (IWS), Winterbergstr. 28, D-01277 Dresden
Intensity and beam divergence in high resolution X-ray diffraction arrangements
are mainly influenced by the quality of the surface shaping
of parallel beam multilayer mirrors, when the beam is coupled into a
channel cut monochromator.
First results of optimisation process of matching of divergence between
multilayer and crystal monochromator are presented.
The resulting beam characteristics are deduced from rocking scan measurements
and coupled Θ −2Θ scans of a silicon single crystal reflection.
Different modifications of V-cut beam compressing crystals are compared
to standard symmetric channel cuts.
Based on the results achieved for Mo-Kα1 radiation which were presented
at the APD-III (NIST, Gaithersburg, 2001) we want to give the
appropriate solution with the highest Cu-Kα1 intensity to a user.