Plenarvorträge - DPG-Tagungen

Halbleiterphysik Donnerstag
HL 39 Hauptvortrag Kaiser
Zeit: Donnerstag 14:30–15:15 Raum: H15
Hauptvortrag HL 39.1 Do 14:30 H15
The Dramatic Developments of Optical Lithography — •W.
Kaiser — Carl Zeiss SMT AG, 73446 Oberkochen
Lithography is the key technology in the chip manufacturing process
to enable continuous shrinking of electronic components on modern ICs,
resulting in cheaper, faster, and less power consumptive devices.
Based on optical design concepts for photographic and microscopy
lenses the optical lithography has experienced a fulminant development
HL 40 SiC I
seen through the last three decades.
The most advanced systems today work at a wavelength of 193nm
and are able to achieve resolution of 90nm and below in high volume
production.
In this presentation the actual state of the art for these systems and
the optical technologies will be shown.
Also recent developments like Immersion Lithography, the trend to
shorter wavelength (157nm) and the long-term perspective to EUV-
Lithography will be addressed.
Zeit: Donnerstag 15:15–16:30 Raum: H15
HL 40.1 Do 15:15 H15
Homoepitaxial growth of 4H-SiC:Ge alloys on 4H-SiC (0001)
substrates by Molecular Beam Epitaxy — •Petia Weih 1 ,
Thomas Stauden 1 , Lothar Spieß 2 , Henry Romanus 2 , Oliver
Ambacher 1 , and Jörg Pezoldt 1 — 1 FG Nanotechnologie, Zentrum
für Mikro- und Nanotechnologien, TU Ilmenau, PF100565, D-98693
Ilmenau, Germany — 2 FG Werkstofftechnologie, Zentrum für Mikround
Nanotechnologien, TU Ilmenau, PF100565, D-98693 Ilmenau,
Germany
Up to date the only intrinsic heterostructures based on SiC are beta-
SiC/alpha-SiC heterojunctions using different bandgaps of different polytypes,
which could not be improved into commercial applications because
of unsolved technological problems. The epitaxy of SiC:Ge alloys provides
the opportunity of bandgap engineering and the realization of alternative
SiC based heterostructures. The draw backs of SiC:Ge alloys are
the thermodynamic instability and the immiscibility of Ge in SiC, which
must be overcome by nonequilibrium material synthesis methods such
as ion beam synthesis or molecular beam epitaxy. In this work for the
first time SiC:Ge thin films were grown homoepitaxially by solid source
molecular beam epitaxy applying (a) continuous fluxes of Si-, C- and Geflux
or (b) atomic layer epitaxy (subsequent deposition of C and Si/Ge)
on on-axis 4H-SiC (0001) substrates. The surface morphology, the chemical
composition and the structure of the grown layers were analysed by
atom force microscopy, scanning electron microscopy with accompanying
energy dispersive X-ray analysis, secondary ion mass spectroscopy and
transmission electron microscopy, respectively.
HL 40.2 Do 15:30 H15
Micro-electromechanical systems based on 3C-SiC/Si heterostructures
— •Christian Förster, Volker Cimalla,
Michael Fischer, Klemens Brückner, Matthias Hein, Jörg
Pezoldt, and Oliver Ambacher — FG Nanotechnologie und FG
Hochfrequenztechnik, Zentrum für Mikro- und Nanotechnologien, TU
Ilmenau, PF100565, 98693 Ilmenau
Wide bandgap semiconductors like SiC are excellent materials for high
temperature, high frequency and high power applications. Furthermore
the properties of SiC are typical for materials suitable for modern applications
in micro-sensors, micro-actuators as well as in micro- and nanoelectromechanical
systems (MEMS, NEMS). Novel applications of SiC/Si
based MEMS and NEMS are dosing and sensor systems for micro- and
nano-fluidic systems, e.g. for fast and reliable biomedical testing and
analysis. We have developed a technology for processing SiC/Si-based
MEMS and NEMS. A micro dosing head for pulmonary amount of liquid
in very small area are realized. This dosing head consist of parallel
operating multi micro pipes running at a defined pressure. Furthermore,
we used 3C-SiC/Si heterostructures to process resonator bars having geometries
in the sub micro meter range. These bars open the possibility
to evaluate the viscosity of water based nano-droplets or to measure the
mass of particles, for example proteins, positioned on the bars.
HL 40.3 Do 15:45 H15
Deep Levels of Gadolinium in Silicon Carbide — •Gunnar
Pasold 1 , Fanny Albrecht 1 , Christian Hülsen 1 , Rainer Sielemann
2 , Wolf Dietrich Zeitz 2 , and Wolfgang Witthuhn 1 —
1 Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-
Wien-Platz 1, 07743 Jena — 2 Hahn- Meitner- Institut Berlin, Glienicker
Straße 100, D-14109 Berlin
Epitaxial layers of hexagonal silicon carbide (SiC) were doped with
the radioactive isotope 149 Gd by recoil-implantation at the HMI (Berlin).
Deep Level Transient Spectra (DLTS) were taken, repeatedly, during the
elemental transmutation 149 Gd → 149 Eu (T1 /2 =9.5 d)
Spectra taken on p-type SiC reveal two deep levels
(ET=EV+0.94±2 eV and ET=EV+0.45±1 eV), undergoing a decrease
in concentration with a half-life of 11±1 d identifying them as Gd
correlated. Whereas the deeper one has been found in 4H and 6H-SiC,
the lower one is observable in the 4H polytype only.
Deep levels with increasing concentrations indicating levels caused by
the daughter element Eu were not observed in the part of the band-gap
of SiC investigated. N-type SiC samples implanted with 149 Gd show no
time dependent deep level concentrations.
HL 40.4 Do 16:00 H15
Oxynitrides on 4H-SiC(0001) — •Patrick Hoffmann and Dieter
Schmeißer — BTU Cottbus, Lehrstuhl Angewandte Physik II /
Sensorik, Universitätsplatz 3-4, 03044 Cottbus
It will be reported on the growth of oxynitride thin layers (≤10nm) on
(0001)-oriented 4H-SiC surfaces. The oxynitride layers were grown by a
thermal treatment of the samples in low pressure N2O ambient. By varying
the growth conditions (N2O pressure, sample temperature, growth
time) different layers were made.
The grown layers were investigated by photoelectron spectroscopy
(XPS) for chemical analysis and by AFM/STM for analysis of the surface
morphology. Concerning the chemical analysis it will be discussed
the general nitrogen content of the samples, the composition of the films
(e.g. content of silicon nitride Si3N4 and silicon oxynitride SiOxNy) and
the sub-oxides which build the interface between SiC and the oxynitride
layers. Concerning the surface morphology mainly the roughness will be
discussed.
The so obtained results for oxynitride thin films on 4H-SiC will be
compared to similarly prepared oxynitride layers on Si(111) investigated
in the past.
HL 40.5 Do 16:15 H15
The sequential annealing of radiation-induced intrinsic defects
in SiC — •M.V.B. Pinheiro, U. Gerstermann, E. Rauls, Th.
Frauenheim, S. Greulich-Weber, and J.-M. Spaeth — Departament
Physik, Universit”at Paderborn, Warburger Str. 100, 33098, Paderborn
, Deutschland
The understanding of sequential annealing dynamics of radiationinduced
defects in SiC has been of highly technological interest. The
main reason for this is that most SiC devices require ion-implantation
doping, which generates intrinsic defects with a high thermal stability.
In this work we present a complete model for the sequential annealing
of several defects generated by electron-irradiation in SiC. Among these
defects there are several unidentified ones that disappear above 150C, the
isolated silicon vacancy that between 600C and 750C is converted in the
silicon antisite - carbon vacancy pair, and finally the D1 center whose concentration
strongly increases above 900C. The latter is the end-product
visible with photoluminescence up to 1700C. Our model is based on a
systematic isochronal annealing investigation performed in 6H-SiC and
4H-SiC with photoluminescence (PL), electron-paramagnetic resonance
(EPR) and magnetic circular dichroism of the absorption (MCDA), and
is fully consistent with ab-initio calculations.