Deliverables and Services - IHP Microelectronics
Deliverables and Services - IHP Microelectronics
Deliverables and Services - IHP Microelectronics
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90 A n n u A l R e p o R t 2 0 0 9<br />
e r S C H I e N e N e p u B L I K A t I o N e N – p u B L I S H e d p A p e r S<br />
(39) on the B<strong>and</strong> Gaps <strong>and</strong> electronic Structure<br />
of thin Single Crystalline praseodymium<br />
oxide Layers on Si(111)<br />
o. Seifarth, J. Dabrowski, p. Zaumseil,<br />
S. Müller, D. Schmeißer, H.-J. Müssig,<br />
t. Schroeder<br />
Journal of Vacuum Science <strong>and</strong> technology B<br />
27, 271 (2009)<br />
the influence of stoichiometry <strong>and</strong> crystal structure<br />
on the electronic properties of single crystalline<br />
cubic pro 2 (111), cubic pr 2 o 3 (111), <strong>and</strong> hexagonal<br />
pr 2 o 3 (0001) thin film heterostructures on Si(111) was<br />
investigated by synchrotron radiation based photoemission<br />
electron spectroscopy (peS) <strong>and</strong> x-ray absorption<br />
spectroscopy (XAS). A detailed analysis of<br />
the complex satellite structures of peS pr 3d lines of<br />
the various pr oxide phases is given. peS was in addition<br />
applied to study the o 2p derived valence b<strong>and</strong><br />
structure <strong>and</strong> the positions of the occupied pr 4f state<br />
density. It is found by a combined peS-XAS study that<br />
especially the b<strong>and</strong> gap values strongly depend on the<br />
stoichiometry <strong>and</strong> crystal structure of the single crystalline<br />
pr oxide layer. Furthermore, the close structure<br />
relationship between cubic pr 2 o 3 (111) <strong>and</strong> pro 2 (111)<br />
films is probably the reason for the detection of nonstoichiometric<br />
behavior, an effect which is far less<br />
pronounced in case of hexagonal pr 2 o 3 (0001) layers.<br />
A possible origin of this effect is given by a surface<br />
modified valence change <strong>and</strong> therefore of importance<br />
to underst<strong>and</strong> in future the epitaxial overgrowth of<br />
these oxide buffer heterostructures by alternative semiconductors<br />
such as germanium.<br />
(40) Synchrotron Microscopy <strong>and</strong> Spectroscopy<br />
for Analysis of Crystal defects in Silicon<br />
W. Seifert, o. Vyvenko, t. Arguirov, A. erko,<br />
M. Kittler, C. Rudolf, M. Salome, M. trushin,<br />
I. Zizak<br />
physica Status Solidi C 6, 765 (2009)<br />
the paper discusses the synchrotron-based microprobe<br />
techniques XBIC (X-ray beam induced current), -<br />
XRF (X-ray fluorescence microscopy) <strong>and</strong> -XAS (X-ray<br />
absorption microspectroscopy) <strong>and</strong> their application<br />
for studying electrical activity of defects <strong>and</strong> preci-<br />
pitation of transition metals in Si materials. Investigations<br />
were performed on samples of block-cast<br />
multicrystalline Si <strong>and</strong> on model samples cut from a<br />
bonded monocrystalline wafer. to analyze the precipitation<br />
sites, ni, Cu <strong>and</strong> Fe were introduced intentionally<br />
into the samples. the detected precipitates<br />
were found to consist of silicides. evidence for metal<br />
precipitates was also found in virtually uncontaminated<br />
as-grown block-cast Si. Besides ni precipitates<br />
detected at a recombination active grain boundary,<br />
particles containing one or several metals (Cu, Fe, ti,<br />
V) were observed. unexpectedly, these particles seem<br />
to exhibit low only recombination activity. Further<br />
studies are necessary to identify their nature.<br />
(41) Synchrotron-based Investigation of Iron<br />
precipitation in Multicrystalline Silicon<br />
W. Seifert, o. Vyvenko, t. Arguirov, M. Kittler,<br />
M. Salome, M. Seibt, M. trushin<br />
Superlattices <strong>and</strong> Microstructures 45, 168<br />
(2009)<br />
We report on investigations of the precipitation of<br />
iron in block-cast multicrystalline silicon using the<br />
techniques of X-ray beam induced current, X-ray fluorescence<br />
microscopy <strong>and</strong> X-ray absorption microspectroscopy.<br />
the samples studied were intentionally<br />
contaminated with iron <strong>and</strong> annealed at temperatures<br />
between 850 <strong>and</strong> 1050 °C. Annealing at 950 °C was<br />
found to lead to well detectable iron precipitation<br />
inside the grains <strong>and</strong> at grain boundaries. Small only<br />
iron clusters were detected after the 850 °C anneal<br />
while no iron clusters were found after the 1050 °C<br />
treatment. X-ray absorption near edge structure analyses<br />
of the iron clusters revealed mostly iron silicide<br />
<strong>and</strong> in one case iron oxide. under the given condition<br />
at the beamline, the detection sensitivity for iron<br />
was estimated to be 4×10 7 atoms, corresponding to a<br />
spherical FeSi 2 particle of 40 nm radius.