The Performance of Channel Cut Collimators for Precision X-Ray Diffraction Studies of Epitaxial Layers

1990 ◽  
Vol 208 ◽  
Author(s):  
Neil Loxley ◽  
D. Keith Bowen ◽  
Brian K. Tanner

ABSTRACTReplacement of the pinhole collimator on a double axis X-ray diffractometer with a device incorporating a channel-cut crystal permits the beam to be pre-conditioned in angular divergence. We examine the merits of such devices, known as channel-cut collimators (CCC's), of different materials and reflections. The experimental performance of InP 004 and Si 022 CCC's is presented.With a reference crystal on the first axis, set in the dispersive peometry with respect to the CCC, conditioning in wavelength spread is achieved. Dispersion broadening is effectively eliminated and no resetting of the reference crystal is required when changing specimen materials or reflections. The devices have extremely low background and reduced Bragg tails. Application of the 4-reflection CCC to rocking curve analysis of thin epitaxial layers, ultra-low angle scattering from biological systems, grazing incidence reflectometry and triple axis diffraction of semi-conductors is discussed.

2020 ◽  
Vol 90 (5) ◽  
pp. 795
Author(s):  
Р.В. Селюков ◽  
В.В. Наумов

Textured Pt films with thickness h=20-80 nm were sputter deposited on oxidized c-Si (100) wafers and annealed in vacuum at 500°C/60 min. The thickness dependencies of the crystalline texture parameters and of the fraction of crystalline phase δ are obtained for as-deposited and annealed films using X-ray diffraction. The determination of δ in textured films is carried out by the new method based on rocking curve analysis. It is found that annealing leads to the texture improvement and to the increasing of δ for all h. The less h, the stronger effects of texture improvement and of δ increasing. These results are explained by the annealing-induced formation of large secondary grains whose volume fraction increases as h decreases. The inhomogeneity of the depth distributions of texture parameters and of δ are investigated for the as-deposited Pt films.


1987 ◽  
Vol 31 ◽  
pp. 143-154 ◽  
Author(s):  
M. Fatemi

AbstractThere is considerable interest in the microelectronics industry to obtain high-resolution images, as well as precise measures of defect densities in “ device quality” thin films and substrates. In the field of x-ray diffraction, research groups worldwide are intensely pursuing the relevant applications of computerized x-ray rocking curve analysis and topography. Production-type, on-site rocking curve instrumentation has already been introduced into the market, and potential uses of x-ray topography are also under consideration.In the present study, the merits and limitations of these two techniques are critically evaluated. Possible pitfalls of automated data collection are pointed out and conditions under which meaningful measurements may be made are explored. It is shown that reliable results may nearly always be obtained with reasonable care when each method is applied subject to its own mode of operation. However, extreme caution is needed when digitized data initially collected for topography is subsequently used for rocking curve analysis; otherwise, the correspondence between the interpretation and actual defect configuration may be vitiated. Thus, additional tests will be necessary to ensure the validity of the results.


1988 ◽  
Vol 126 ◽  
Author(s):  
M. Fatemi ◽  
P.E. Thompson ◽  
J. Chaudhuri ◽  
S. Shah

ABSTRACTThe effect of rapid thermal annealing on strain reduction in 1.15 MeV S-implanted GaAs wafers irradiated to a dose of 5 × 1014/cm2 has been studied by double-crystal x-ray diffraction technique. X-ray rocking curves exhibit characteristic thin film fringes between the peak of unstrained GaAs and the major peak of the strained region. The maximum strain, i.e., the separation between the two peaks, as well as the number of minor fringes decreases with increasing RTA temperature, while the relative spacing between the fringes remains constant. At temperatures above 900°C, the main peaks begin to overlap; however, a residual positive strain can be measured for temperatures as high as 1100°C.


2013 ◽  
Vol 1576 ◽  
Author(s):  
Jacob Castilow ◽  
Timothy W Zens ◽  
J. Matthew Mann ◽  
Joseph W. Kolis ◽  
Colin D. McMillen ◽  
...  

ABSTRACTHydrothermal synthesis of ThO2, UxTh1-xO2, and UOx at temperatures between 670°C and 700°C has been demonstrated. Synthesis at these temperatures is 50-80°C below prior growth studies and represents a new lower bound of successful growth. ThO2 single crystals of dimensions 6.49mm x 4.89mm x 3.89 mm and weighing 0.633g have been synthesized at average growth rates near 0.125mm/week. Single crystal UxTh1-xO2 crystals with mole fractions up to x≈0.30 have also been grown. The largest alloyed crystal with mole fraction x≈0.23 has dimensions of 2.97mm x 3.23mm x ∼3mm and recorded average growth rates near 0.2mm/week. Four structures were solved from X-ray diffraction data and their crystallographic data reported here. Rocking curve analysis determined a dislocation density of 1.2×109 cm-2.


2011 ◽  
Vol 98 (2) ◽  
pp. 021912 ◽  
Author(s):  
M. Barchuk ◽  
V. Holý ◽  
B. Miljević ◽  
B. Krause ◽  
T. Baumbach

2008 ◽  
Vol 600-603 ◽  
pp. 223-226 ◽  
Author(s):  
Günter Wagner ◽  
J. Schwarzkopf ◽  
M. Schmidbauer ◽  
R. Fornari

3C-SiC epitaxial layers were grown on on-axis Si (001) substrates by low-pressure hot-wall chemical vapour deposition. Depending on the growth parameters, the residual strain in the 3C-SiC layer was seen to be tensile or compressive. In this work, the influence of parameters, such as growth temperature and C/Si ratio in the vapour phase, on residual strain and macroscopic layer bow is investigated. We found that the wafer bow changes from convex, at a deposition temperature of 1270° C, to concave at 1370° C. High resolution x-ray diffraction data indicate that the crystal-line perfection of the layers is lower for decreasing deposition temperature and increasing compres-sive strain. No remarkable influence of the C/Si ratio in the gaseous atmosphere on the FWHM of the rocking curve was observed.


Author(s):  
W. Z. Chang ◽  
D. B. Wittry

Since Du Mond and Kirkpatrick first discussed the principle of a bent crystal spectrograph in 1930, curved single crystals have been widely utilized as spectrometric monochromators as well as diffractors for focusing x rays diverging from a point. Curved crystal diffraction theory predicts that the diffraction parameters - the rocking curve width w, and the peak reflection coefficient r of curved crystals will certainly deviate from those of their flat form. Due to a lack of curved crystal parameter data in current literature and the need for optimizing the choice of diffraction geometry and crystal materials for various applications, we have continued the investigation of our technique presented at the last conference. In the present abstract, we describe a more rigorous and quantitative procedure for measuring the parameters of curved crystals.The diffraction image of a singly bent crystal under study can be obtained by using the Johann geometry with an x-ray point source.


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