Abstract: The interstitial carbon impurity (CI) vibrational modes in monocrystalline Si-rich SiGe
were investigated by Fourier Transform Infra Red spectroscopy and density functional modelling.
The two absorption bands of CI are found to be close to those in silicon, but show shifts in opposite
directions with increasing Ge content. The transversal mode band at 932 cm-1 shifts slightly to the
high frequency side, while the longitudinal mode at 922 cm-1 suffers a pronounced red-shift. Each
Ci-related band is found to consist of two components. An annealing of CI in Si1-xGex occures in
two stage. During the first stage (210-250 K) the main components of bands anneals and revealed
components grow in intensity. At T>250 K all components disappear. Two component structure of
bands is suppose most likely correspond to different combinations of Si and Ge atoms in the
neighbourhood of the carbon atom. The interstitial carbon defect was modelled by a supercell
density-functional pseudopotential method (AIMPRO) for alloys with 4.69% Ge concentration.
From energetics, it has been found that each Ge-C bond costs at least 0.4 eV in excess of a Si-C
bond. However, structures where Ge atoms are second neighbors to the C atom are marginally
bound, and may explain the two-component band structure in the absorption measurements. The
vibrational mode frequencies taken from several randomly generated SiGe cells produce the
observed opposite shifts for the transverse and longitudinal modes.
Abstract: The effect of preparation conditions and annealing treatment on Si-rich-SiOx layers was
investigated. It was observed that oxygen plays important role in the creation of light-emitting
centres. It was found that the emission in the green-orange spectral range is connected with silicon
oxide defects which contain dangling bonds. At the same time PL band in the infrared spectral
range is caused by recombination of carriers in amorphous silicon or nanocrystalline one. It is
shown that modification of defect content under various treatments gives the possibility to control
the emission properties of the layers.
Abstract: This paper presents the results of PL spectrum studies for Si nano-crystallites embedded
in amorphous silicon matrix. Investigated layers were deposited by the hot-wire CVD method on
glass substrates at the wafer temperature 300°C and different filament temperatures from the range
1650-1950°C. It was shown that variation of temperatures of filament (hot-wire) allows to produce
the films with desirable parameters. Using of X-ray diffraction and photoluminescence methods the
correlation between some photoluminescence bands and the sizes of Si nano-crystallites as well as
the amorphous phase volume was shown. The nature of light emission is discussed.
Abstract: First relaxation stages in Si1-x Gex layers on Si substrates are induced by annealing of
metastable, low-temperature buffer layer samples and observed by X-ray topography (XRT). This
method allows observing large area (several square millimetres) of a sample and reveals very low
densities of defects, located in the layer as well as in the substrate. It allow to follow the evolution
of the very first steps of the relaxation, starting with dislocation crosses which were characterized
and evolving to misfit dislocation network by very low increases of thermal budget. It is proposed a
nucleation mechanism of these crosses based on Frank loops due to point defects condensation
which can transform locally in glide dislocations under the influence of the biaxial stress in the film.
Abstract: The electrical properties of structures included 1-octadecene (CnH2n, n=18) monolayers
deposed onto the oxide-free silicon surface or Si/SiGe/Si layers were analyzed as a function of
surface pretreatment (hydrogen- or iodine-terminated silicon surface) and layer deposition regime
(thermal- or photo-activated process). Two types of traps (for electrons and holes) were found at the
interface between the monolayers and substrate. The density of traps was shown to depend on the,
H- or I-termination of the silicon surface, the illumination intensity and deposition time during
photo-activated deposition, and the temperature of thermal-activated deposition. The optimal
regimes can be chosen for minimization of the surface charge in the structures covered with 1-
octadecene monolayers, which provides a high conductivity of thin near-surface layers.
Abstract: Angular correlation of annihilation radiation technique (ACAR) has been used for
studying a microstructure of the vacancy-group-V-impurity complexes (DV) formed by irradiation
with 60Co γ – rays at Tirr. ≈ 280K in oxygen-lean n-Ge doped with group-V-impurity atoms As, Sb,
and Bi. The probability of annihilation of positrons with the core electrons of DV complexes to be
reconstructed from ACAR spectra has been analyzed on the basis of Chapman-Kolmogorov
formalism; the Coulomb repulsion is proved to regulate the penetration of a positron into Ge4+ and
D5+ ion cores. In passing from AsV to SbV and BiV complexes the ion cores D5+ are found to
contribute more effectively to the probability of the positron annihilation in the core region. These
data correlate well with the augmentation of the entropy of ionization (4S ~ 2,9 ÷ 4,2K) observed
by means of capacitance transient techniques with the use of Au-Ge Schottky barriers in the same
row of a similar vacancy-impurity complexes. The results obtained by ACAR spectroscopy suggest
the full-vacancy configuration of DV pair with relaxation of atoms inward towards the vacancy.
Abstract: This paper presents an investigation of the impact of a Highly Doped Drain (HDD)
implantation after epitaxial deposition on Si1-xGex S/D junction characteristics. While the no HDD
diodes exhibit the usual scaling of the leakage current density with Perimeter to Area (P/A) ratio,
this is not the case for the HDD diodes, showing a smaller perimeter current density JP for smaller
window size structures, corresponding with larger P/A. This points to a lower density of surface
states at the Shallow Trench Isolation (STI)/silicon interface, which could result from a lower
compressive stress. In order to examine the role of the HDD implantation damage, Transmission
Electron Microscopy (TEM) inspections have been undertaken, which demonstrate the presence of
stacking faults in small active SiGe regions. These defects give rise to local strain relaxation and,
therefore, could be at the origin of the lower STI/Si interface state density. The window size effect
then comes from the active area dependence of the implantation defect formation.
Abstract: (001) n-type Ge has been implanted at given fluence and intermediate temperature with
hydrogen ions using two processes: conventional in-line implantation and plasma based ion
implantation. The as-created microstructure has been compared using transmission electron
microscopy. In particular, it has been shown that the major differences observed are due to the
implantation temperature, much higher during the PBII process. This suggests that plasma based ion
implantation could be used for layer transfer in spite of a higher surface roughness observed after
the PBII process.
Abstract: In this study, Co germanide Schottky barrier diodes on n-Ge (100) substrate were
fabricated by sputtering metal Co on Ge, followed by annealing in vacuum at 700°C. The influence
of annealing time was investigated on both the electrical properties of Co germanide Schottky
barrier diodes and on the phase formation on n-Ge (100) substrate. With increasing annealing times
growing or transformation of germanide entities occurs leading to reduction of the trap
concentration and therefore the leakage current.