X-ray interferometric investigation of deformation fields in ion-implanted silicon crystals

The results of investigation of deformation fields in the block of a three-crystal X-ray silicon interferometer subjected to ion implantation by X-ray diffraction moir patterns are presented. The condition of applicability of the expression to determine the moir pattern period when intracrystalline deformations are estimated has been found.     

Superheat of silicon crystals observed by live X-ray topography

In-situ observations of Si crystal growth and melting have been carried out by live X-ray diffraction topography. Superheated solid states beyond the melting point was observed for dislocation-free crystals with melting in their inside. Dislocations were found to impede superheat and to melt the crystal without an appreciable superheating. A slightly superheated state accompanying melting removes all dislocations including immobile ones by their climb motion. It is proposed that self-interstitials needed for the volume change by melting are supplied by climb of dislocations, in contrast to dislocation-free crystals creating the interstitials thermally. In real crystal growth, remelting occurs naturally by melt convection and acts to make the growing crystal dislocation-free.     

X-ray diffraction study of silicon single crystals highly doped with boron

The section Lang method of X-ray diffraction topography in combination with X-ray diffractometry based on the Borrmann effect was previously shown to be effective for detection of cluster formation during the growth process of highly doped Si-Cz single crystals. In the present work, the same techniques have been used to choose the best condition of technological heat treatment of boron-doped silicon from the view-point of formation of microdefects. The concentration and average size of dislocation loops have been calculated for two conditions of standard heat treatment from the analysis of diffusion scattering. The distribution of dislocation loops along the growth axis and crystal diameter has been determined as well.     

X射线激发荧光光谱仪的建立及闪烁晶体发光表征

利用X射线作为激发光源,自行组装并实现计算机控制的X射线激发荧光光谱仪.介绍了X射线激发荧光光谱仪的建立及其结构特性.该仪器具有时间分辨率高、测量动态范围大、使用方便等优点,可应用于晶体、粉末和液体等各种样品的测量,该仪器同时还具有很强的扩展性.     

Combined multiparametric X-ray diffraction diagnostics of microdefects in silicon crystals after irradiation by high-energy electrons

The quantitative diagnostics of complex defect structures in silicon crystals grown by the Czochralski method and irradiated with different doses of high-energy electrons (18 MeV) is performed by methods of high-resolution X-ray diffraction. The analysis is based on analytical formulas of the statistical dynamical theory of X-ray diffraction in nonideal crystals with randomly distributed defects of several types. Using the combined treatment of reciprocal space maps and rocking curves, the concentration and average radii of dislocation loops, as well as the concentration and radii of oxygen precipitates in the silicon samples, are determined.     

类锂硅离子软X射线激光的空间特性

本文报道类锂硅离子软X射线激光的空间分布特性,研究表明软X射线激光的最佳增益在离靶面约300μm的中等等离子体密度区,而临近靶面的高密度区增益则较小.     

A quantitative study of diffracted X-ray intensities from type I natural diamond crystals by high resolution X-ray diffractometry and comparison with nearly perfect silicon single crystals

Results of accurate measurements of peak and integrated intensities of , 111 and 333 reflections of natural diamonds of type I and nearly perfect silicon single crystals are reported. Highly monochromated and collimated MoK _{α 1} exploring beam was used. A quadrupole crystal X-ray diffractometer was employed in (+, −, +) and (+, −, +, −) settings. (111) platelets of diamond and silicon crystals with thicknesses of about 1 mm were selected. High resolution diffraction curves, stationary and traverse topographs were recorded. Diffraction curve half widths of diamond and silicon crystals were in the range: 45–200 arc sec and a few arc sec respectively. The experimental values of integrated intensitiesρ for diamond crystals were found to lie between the theoretical values for ideally perfect and ideally imperfect crystals. Experimental values ofρ for silicon were closer to the “perfect crystal” values. This is consistent with the results of diffractometric and topographic evaluation. The peak intensities of all reflections were higher for diamond crystals in comparison to the silicon crystals. The ratioI _C/I _Si lies in the range 1.3 (111 reflection) to 10.5 and (333) reflections. This is anomalous and cannot be accounted for by considering the degree of perfection, structure factor and difference in absorption coefficient.     

Microplasticity of silicon crystals

The low-frequency (1 Hz) internal friction (Q^–1) method was used to study the microplasticity of silicon whisker crystals grown by the method of chemical gas-transport reactions in a closed ampoule. A study was made of p-type crystals with the growth axis 111, 1–60 in diameter, working length 1–3 mm, both in the original state and after plastic ( 1%) deformtion by torsion. The temperature and amplitude dependences of Q^–1 were studied in 5·10^–5 torr vacuum. The amplitude of alternating vibrations was within the range 10^–5–10^–3 and the axial stresses were 10⁶–10⁷ N/m². The experimental results led to the conclusion that the microplasticity of undeformed silicon whiskers was due to heterogeneous nucleation of dislocations in stress concentration regions near surface defects, assisted by thermal fluctuations. In deformed whiskers the microplasticity was attributed to the nucleation and motion along dislocations of single and double thermal kinks in accordance with the Seeger model.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 88–93, May, 1980.     

Anomalously large changes in diffracted X-ray intensity from silicon single crystals produced by microwave fields

Results of a high resolution X-ray diffraction study of effects produced by microwave fields of frequency 2.45 GHz in silicon single crystals are reported. Microwaves travelled along a strip line evaporated along a diameter of the specimen crystal disc, which was aligned for diffraction from a desired set of lattice planes. Diffraction curves and high resolution traverse topographs were recorded and curvature measurements were made before, during and after application of the microwave field. An anamalously large increase in diffracted X-ray intensity from a large volume of the specimen was observed on application of the microwave field. The peak intensity in some cases increased by more than ten times. Integrated intensity also showed similar large changes. No significant change in the shape of the diffraction curves was observed upto microwave powers of ～10W. Some regions of the crystals showed a large decrease in intensity. High resolution traverse topographs directly showed the changes in intensity. Also, dot like defects were observed. Most of these changes were reversible. However, some irreversible effects were observed which suggest the possible use of this method in microwave field/power measurement as well as dosimetry. The observed effect could be due to influence of the field on the dispersion surface or due to strong interaction of the field with electron cloud of silicon atoms.     

X-ray topography of polydiacetylene single crystals prepared by using physical vapor growth technique

The lattice defects in polydiacetylene (PDA) single crystals prepared using physical vapor growth were investigated by white beam X-ray topography. Line patterns along the [0 0 1] and [1 0 2] directions were clearly observed. Appearance of the line patterns along the [0 0 1] direction proves the polymerization direction predicted by Hädicke et al. The topographic results are in good agreement with the surface morphologies investigated by atomic force microscopy (AFM).     

Investigation of the physical properties of piezo-and ferroelectric crystals by high-resolution X-ray diffraction and topography

The acoustic properties of lanthanum-gallium tantalate crystals and the polar properties of ferroelectric lithium niobate crystals have been investigated by high-resolution X-ray diffraction and topography. It is shown that analysis of the diffraction spectra of acoustically modulated crystals makes it possible to determine the acoustic amplitudes and power flow angles. It was also demonstrated that investigation of the domain structure in ferroelectric crystals under the conditions of the inverse piezoelectric effect allows one to study the domain structure.     

X-ray interferometry study of deformation fields in silicon crystals,induced by a constant magnetic field

The results of investigations of deformation fields in the dual-use unit of a silicon triple-crystal X-ray interferometer under constant magnetic field by means of Moiré X-ray-diffraction patterns are presented. Structural distortions are found in nonpolar silicon semiconductor crystals. It is shown that a magnetic field causes a change in the period of the Moiré patterns obtained using the X-ray interferometer; the Moiré patterns disappear at a certain value of the magnetic field strength.     

Surface morphological instability of silicon (100) crystals under microwave ion physical etching

This paper presents the results of studies of the dynamics of relaxation modification of the morphological characteristics of atomically clean surfaces of silicon (100) crystals with different types of conductivity after microwave ion physical etching in an argon atmosphere. For the first time, the effect of the electronic properties on the morphological characteristics and the surface free energy of silicon crystals is experimentally shown and proven by physicochemical methods.     

Magnetoplasticity and diffusion in silicon single crystals

The effect of static magnetic fields on the dynamics of surface dislocation segments, as well as the diffusion mobility of a dopant in silicon single crystals, has been analyzed. It has been experimentally found that the preliminary treatment of p-type silicon plates (the dopant is boron with a concentration of 10¹⁶ cm⁻³) in the static magnetic field (B = 1 T, a treatment time of 30 min) leads to an increase in the mobility of surface dislocation segments. The characteristic times of observed changes (about 80 h) and the threshold dopant concentration (10₁₅ cm⁻³) below which the magneto-optical effect in silicon is not fixed have been determined. It has been found that diffusion processes in dislocation-free silicon are magnetically sensitive: the phosphorus diffusion depth in p-type silicon that is preliminarily aged in the static magnetic field increases (by approximately 20%) compared to the reference samples.     

Positron trapping in electron-irradiated silicon crystals

The positron lifetime in electron-irradiated undoped and doped silicon crystals is studied as a function of temperature between 90 and 300 K. We show that the temperature dependence of the two lifetime components does not arise from the escape, but from the trapping rate at defects. The temperature dependences of the capture cross sections are deduced. It is concluded that in undoped crystals the positrons interact with negatively charged and neutral defects, probably divacancies and vacancy-oxygen complexes, respectively. In strongly P-doped crystals positron trapping occurs preferably in negatively charged centers.     

Negative crystals of silicon carbide

Systems of negative silicon carbide crystals are classified and studied by experimental methods. The crystal structure and morphology forming during growth, etching, and erosion are discussed.     

Geometrical aberrations and physical characteristics of approximately focusing X-ray monochromators of Johann's type

A model is described for the computation of the diffracted intensity distribution on monochromating crystals in approximatively focusing monochromators of Johann's type. Numerical examples and graphs illustrate the influence of geometrical aberrations in some practical cases. Results of computations allow rules to be drawn up for the choice of parameters of these monochromators according to the requirements of the diffraction problem which is being solved.     

Impurity micropotentials in commercial silicon crystals

The use of very cold neutrons, of laser mass spectrometry, and of secondary-ion mass spectrometry has revealed the presence of microprecipitates in commercial Si crystals grown by the Czochralski method and by float zoning.Neutron-Physics Laboratory, Lebedev Physics Institute, Academy of Sciences of the USSR. Translated from Preprint No. 149 of the Lebedev Physics Institute, Academy of Sciences of the USSR, Moscow, 1988.     

X-ray diffraction investigation into the specific features of the growth kinetics of oxygen-containing precipitates in Czochralski-grown silicon crystals

The formation and growth of defects (precipitates and dislocation loops) during isothermal decomposition of a supersaturated oxygen-containing solid solution in Czochralski-grown silicon crystals are investigated using triple-crystal x-ray diffractometry. It is established that oxygen-containing precipitates grow through diffusion and that the formation of dislocation loops is associated with both the coagulation of embedded silicon atoms and the generation of dislocation loops by stresses induced in the vicinity of the oxygen-containing precipitates.