The formation of iron silicide nanocrystals (NCs) and their embedding into monocrystalline silicon was studied. Solid phase epitaxy of 0.4 nm Fe at 630 °C resulted in formation of NCs consisted of β-FeSi2 and ε-FeSi phases. Annealing of NCs at 750 °C for 90 min led to transformation of β-FeSi2 and ε-FeSi into α-FeSi2. On the other hand, silicon layer growth over as-formed NCs, at the same temperature, resulted in formation of single phase NCs consisted of β-FeSi2. Silicon deposition rate proved to be the crucial point for a full embedding of NCs. The rate of 1 nm/min resulted in emersion of NCs to the surface during silicon overgrowth irrespective of Si cap layer thickness, while the rate of 8 nm/min led to the full embedding of β-FeSi2 NCs. Both incompletely and fully embedded β-FeSi2 NCs have epitaxial relationship and stress favorable for an indirect to direct band-gap transition at Y point.
The morphology and optical properties of Si samples implanted by low-energy Fe+ ions with different fluencies (1×1015
- 1.8×1017 cm-2) and further subjected to pulsed ion-beam treatment (PIBT) have been studied by atomic force
microscopy and optical reflectance spectroscopy. It was proved that the iron disilicide ( β-FeSi2) crystallites have been
formed on the surface of Si substrate as a result of ion implantation and PIBT. The method of ultrahigh vacuum and low-temperature
(Τ = 850°C) cleaning of Fe+-implanted Si samples has been used for the first time. It was found that it is
possible to form smooth epitaxial Si films with reconstructed surface and thickness up to 1.7 μm by molecular beam
epitaxy (MBE) on the surface of Si samples implanted at a fluence of up to 1×1016 CM-2. Further increasing implantation
fluence results into disruption of epitaxial Si growth and strong increase of surface relief roughness due to 3D silicon
growth mechanism. Preservation of β-FeSi2 precipitates inside Si matrix after the formation of a cap epitaxial Si layer
has been confirmed by optical spectroscopy data. Low temperature photoluminescence measurements in the range of
1400-1700 nm showed that light emission of the Si/ β-FeSi2/Si heterostructures formed is due to contributions from β-
FeSi2 precipitates and dislocations.
Morphology, optical properties, crystal and electronic structure of monocrystal silicon after plasma processing,
depending on initial voltage of magnetoplasma compressor (MPC), have been studied. It was shown that periodic surface
structures are formed on silicon only in the short range ofinitial MPC voltages (2.8-3.2 kV), but at higher initial voltages
(3.4-3.6 kV) the formation of "crater" and carrying out of the part of material on its periphery till the moment of
crystallization is observed without the formation of surface structures. The decrease of the silicon lattice constant has
been observed after plasma processing at all initial voltages that correlates with the decrease of band-gap energy by data
of optical spectroscopy. Changes in crystal lattice and electronic structure of silicon modified by compression plasma
flow have confirmed by red shift of 4.5 eV peak in reflectance spectra and decrease of its amplitude.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.