Estudo estrutural de nanossistemas semicondudores e semicondutores implantados por difração de raios-X de n-feixes / Structural study of semiconductors nanosystems and implanted semiconductors by means of n-beams X-ray diffraction

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

In this paper, X-ray multiple diffraction (MD) associated with the advantages of synchrotron radiation appears as a high-resolution microprobe and it is used to obtain relevant contributions to the study of structural properties of semiconductor materials, as they present themselves nanosystems epitaxial or implanted with ions. The study and detection of negative hybrid reflections (interaction epitaxial layer/substrate) coherent (CHR) in substrate Renninger scans (RS) is one of the contributions of this thesis. The ?:f mapping, i.e., the scanning of the (113)(111) secondary reflection diffraction condition shows that the CHR negative that appears is, in fact, the destructive interference between the layer secondary reflection and the substrate primary reflection. It is emphasized here the importance of a detailed measurement of the diffraction condition of adequate MD secondary reflections. The use of the MD special case named Bragg-Surface Diffraction (BSD), in which the secondary reflection propagates parallel to the single crystal surface or interfaces in heterostructures, when involves secondary reflections that are sensitive to the crystalline lattice symmetry, is another relevant contribution of this thesis. The substrate (GaAs) RS peak, which stands for the (000)(004)(022)(022) four-beam case that splits into two three-beam peaks GaInP layer RS by tetragonal distortion was used as a novel tool in the study of tetragonal distortions, even for thin epitaxial layers. Moreover, the presence of orthorhombic distortion or even monoclinic one, can be investigated by measuring the two pairs of secondary peaks (022)(022)and (202)(202) also present in the same ternary layer RS. Other thesis contributions are in the application of DM to the study of SiO2/Si(001) crystals implanted with Fe+, which were submitted to Ion Beam Induced Epitaxial Crystallization process (IBIEC) and then, annealed. ?:f mappings of the (000)(002)(111) BSD peak gave rise to perpendicular and in-plane lattice parameters and strains for the stressed regions provoked by the ?-FeSi2 nanoparticles formation provided by IBIEC. For another set of similar samples except for the absence of the oxide, the interesting formation of oriented plate-like ?-FeSi2 nanoparticles, that were observed by TEM and confirmed by (002) rocking curves obtained at MD condition for the BSD (111) and (1 peaks and the ?:f mappings that provided anisotropic in-plane strains in IBIEC sample. Nanoparticles spherical-like also detected by TEM induce isotropic strains and the samples structural characterization was obtained using the same above mentioned manner. Measurements of the reciprocal space mapping (RSM) using symmetric and asymmetric reflections were important to confirm the implanted crystal results obtained by MD by allowing to observe the periodic and lateral composition variation in the GaInP layer as well as, to confirm the effect of the height of InP quantum dots grown on the ternary layer in the strain degree they cause in the ternary cap layer, it means, the greater the height the greater the level of strain in the cap layer

ASSUNTO(S)

semicondutores implantação iônica raios x - difração multipla pontos quânticos semiconductors ion implantation x-rays quantum dots

ACESSO AO ARTIGO

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