Structure perfection variations of Si crystals grown by Czochralski or floating zone methods after implantation of oxygen or neon atoms followed by annealing

Structure perfection of the silicon crystals grown by the Czochralski and floating zone methods after implantation with oxygen or neon fast iones followed by annealing at the temperatures T ~ 1050-1150 ⁰0C, when large SiOx precipitates were formed, was studied by means of various X-ray diffraction methods. Considerable increments of integral reflectivities for different Bragg reflections of such samples in comparison with those calculated for a perfect crystal were detected. Broadening of the spatial intensity distribution curves for the Bragg-diffracted beams taken by a single crystal spectrometer as well as the maps of the diffuse isointensity distribution near a reciprocal lattice point, registered by the Philips high-resolution diffractometer, are shown. All of these diffraction effects related to creation of the SiOx precipitates formed on structural damages caused by implantation of oxygen or neon ions and subsequent annealing. Contrary to FZSi, where the appearence of SiOx precipitates was discovered due to intensive diffuse scattering near the layer contained the implanted oxygen ions only, in the case of CZSi samples with larger concentration of oxygen (up to 1*10¹⁸ at/cm³) such defects were formed not only near the burried layer, created by ions of oxygen or neon (with energy E = 4 MeV, dose 10¹⁴cm⁻²) but in a bulk of a crystal. Annealing of the FZSi crystals implanted by oxygen (E ~ 200 keV, dose ~ 10¹⁶-10¹⁷ cm⁻²) at enhanced hydrostatic pressure, additionally stimulated SiOx precipitation close to the implanted layer

X-Ray Standing Wave Technique as a Tool in the Study of the Imperfect Crystals

The application of the X-ray standing wave (XSW) technique in the case of imperfect crystals meets serious theoretical and interpretational problems. However, well-known advantages of the XSW technique make it especially interesting to the study of the ordering of impurities and of various processes leading to changes in this ordering in various likes of imperfect crystals. In this work we try to answer the question how imperfection of a crystal may influence the changes in fluorescence yield during the XSW measurement. Two likes of imperfect crystals are studied: Si(111) implanted with high energetic Bi$\text{}^{+}$ ions, and Zn$\text{}_{1-x}$Co$\text{}_{x}$Se single crystal with natural (111) face. The discussion of obtained results shows that general features of the X-ray standing wave field are conserved despite the considerable imperfections of the crystals. The results seem to support the applicability of the XSW technique to the study of imperfect materials, although some further theoretical effort would be required

SOME REMARKS TO THE PROBLEM OF THE DISLOCATION LOOPS CREATION IN THE REGION OF INTERFACE

Dans ce travail, on discute des conditions de création de boucles de dislocations autour de précipités Ag2Te-α, dans les cristaux de ZnTe. Les facteurs d'accomodation ont été calculés pour ce type de précipités. A partir de ces calculs, on discute le problème des variations de déformation entre les parties implantées et non implantées de cristaux de Si, après recuit.The aim of this work is discussion on the conditions of dislocation loops created round the Ag2Te - α in ZnTe crystals. The misfit factor for this kind precipitates has been calculated. On the base of obtained results, the problem of strain changes between implanted and non-implanted parts of Si crystals after annealing process have been discussed

X-RAY AND SCANNING CATHODOLUMINESCENCE IMAGING OF SMALL-ANGLE GRAIN BOUNDARIES AND DISLOCATIONS IN CdTe CRYSTALS

En utilisant d'une part la topographie de rayons X (RXT), et d'autre part la microscopie électronique à balayage en mode cathodoluminescence (CL-IR), nous sommes en mesure de visualiser les défauts du réseau dans les monocristaux de CdTe. La possibilité d'identification du défaut est un avantage de la technique RXT. De plus, la surface examinée peut être imagée. La cathodoluminescence garantit cependant une meilleure résolution. Les défauts observés en cathodoluminescence dans des cristaux de CdTe ont été identifiés comme des sous-joints et des dislocations à vis.By employing the Reflection X-ray Topography (RXT), on one hand, and the cathodoluminescence (CL-IR) mode of operation of the Scanning Electron Microscope, on the other hand, we are able to visualize the lattice defects in CdTe sinole crystals. The possibility of defect identification is the advantage of the RXT technique. Moreover, the examitied surface can be imaged as a whole. Cathodoluminescence however, guarantees higher resolution. The defects in CdTe crystals, observed in cathodoluminescence images, have been identified as small-angle boundaries and screw dislocations

EXTENDED X-RAY BREMSSTRAHLUNG ISOCHROMAT FINE STRUCTURE

The extended x-ray bremsstrahlung isochromat fine structure (EXB I FS) has been measured for Pd, Ag, Ni and Cu metals at the photon energy of 5415 eV. The radial distribution functions have been obtained by using the Fourier transform of EXB I FS' s

Investigations of surface morphology and microrelief of GaAs single crystals by complementary methods

The paper presents the study of morphology and roughness of (100) surfaces of GaAs single crystals grown by the Czochralski method. The surfaces were prepared in a different way: mechanical polishing, chemomechanical polishing, mechanical grinding, wet polishing etching, anisotropic etching. The X-ray grazing incidence reflectivity, atomic force microscopy, scanning tunneling microscopy, optical specular reflection, and profilometric methods were complementary used. The application of these methods allowed to reveal the details of differences in the surface morphology varied with the way of its preparation

X-Ray and Electron-Optical Characterization of ZnTe/CdTe and ZnTe/GaAs Epitaxial Layers Obtained by the MBE Method

X-ray diffraction topography (Bragg diffraction) and X-ray rocking curve measurements were used to study the perfection and structural properties of ZnTe epitaxial layers on the CdTe and GaAs substrates. ZnTe epitaxial layers on CdTe were grown by MBE method by using a machine made in the Institute of Physics of the Polish Academy of Sciences. The ZnTe layers on GaAs were produced on the other, factory-made MBE system. The comparison between the X-ray topographical images of the substrate and epitaxial layer shows that imperfections on the substrate surface cause imperfections in the epitaxial layer. The results of double-crystal diffractometry measurements show that the perfection of the layer on the GaAs substrate is higher than that on the CdTe. The presence of microtwining in the ZnTe layer on the CdTe substrate was confirmed by RHEED measurements. The X-ray standing wave fluorescent spectra were also measured for the samples

Study of Si(111) Implanted with As Ions by X-Ray Diffraction and Grazing Incidence Methods

The Si(111) wafer cut from a bulk single crystal obtained by the Czochralski method was implanted with 5×10$\text{}^{16}$ I cm$\text{}^{-2}$ of As ions of energy 80 keV. The dose applied was chosen above the amorphization limit of the silicon substrate. Two samples, implanted and a reference, were studied by grazing incidence X-ray reflectometry and X-ray diffraction methods using a high resolution Philips MRD system equipped with a Cu source and a channel-cut monochromator. The obtained spectra were compared with distributions of ion range and defect production calculated with TRIM program [1], as well as with theoretical models of reflectivity [2, 3]. The results of grazing incidence X-ray reflectometry reflectivity of the implanted sample show well-pronounced oscillations, which can be associated with a layer about 50 nm thick, approximately comparable to the thickness of the defected layer estimated from the TRIM method. Theoretical calculations of reflectivity clearly indicate an occurrence of a Si layer of electron density lower about 10-15% comparing to the unimplanted Si sample. This can be due to the vacancy production during ion implantation. A comparison of the spectra with a density distribution profile concluded from the TRIM calculations shows large discrepancies. The results indicate the applicability of grazing incidence X-ray reflectometry method in a study of amorphization processes in implanted layers