Observation of the strain field near the Si(111) 7 × 7 surface with a new X-ray diffraction technique

1998 ◽  
Vol 5 (3) ◽  
pp. 964-966 ◽  
Author(s):  
Takashi Emoto ◽  
Koichi Akimoto ◽  
Ayahiko Ichimiya
Keyword(s):  
Strain Field ◽  
Critical Angle ◽  
Total Reflection ◽  
Surface Structures ◽  
Native Oxide ◽  
Oxide Surface ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glancing Angle

A new X-ray diffraction technique has been developed in order to measure the strain field near a solid surface under ultrahigh vacuum (UHV) conditions. The X-ray optics use an extremely asymmetric Bragg-case bulk reflection. The glancing angle of the X-rays can be set near the critical angle of total reflection by tuning the X-ray energy. Using this technique, rocking curves for Si surfaces with different surface structures, i.e. a native oxide surface, a slightly oxide surface and an Si(111) 7 × 7 surface, were measured. It was found that the widths of the rocking curves depend on the surface structures. This technique is efficient in distinguishing the strain field corresponding to each surface structure.

X-Ray Diffraction Contrast from Impurity Precipitates in CdS Single Crystals

1966 ◽  
Vol 10 ◽  
pp. 153-158 ◽  
Author(s):  
Jun-ichi Chikawa
Keyword(s):  
Strain Field ◽  
Crystal Surface ◽  
Bragg Angle ◽  
X Rays ◽  
Bragg Condition ◽  
X Ray Diffraction ◽  
Crystal Surfaces ◽  
X Ray ◽  
Impurity Doped ◽  
Free Plane

AbstractImpurity-doped crystals CdS(GaGl3) have been studied by X-ray topography. Some large precipitates are formed close to the crystal surfaces by annealing at 300°C. In the symmetrical Laue case, the precipitates show circular images (30-60 μ in diameter) due to the radial strains around the precipitates which consist of two semicircles separated by a contrast-free plane parallel to the reflecting plane. The observations indicate that the strain field between the crystal surface and precipitate is not responsible for the contrast, and that the images are formed by X-rays which are deviated from the Bragg condition for the perfect region and satisfy the Bragg condition in the strain field on the inside of the precipitate. One of the semicircles is formed by the incident X-rays with larger glancing angles than the Bragg angle and the other with smaller ones. It is concluded that this contrast is due to the strain around a convex lens shaped precipitate.

scholarly journals Multiple scattering in grazing-incidence X-ray diffraction: impact on lattice-constant determination in thin films

2016 ◽  
Vol 23 (3) ◽  
pp. 729-734 ◽  
Author(s):  
Roland Resel ◽  
Markus Bainschab ◽  
Alexander Pichler ◽  
Theo Dingemans ◽  
Clemens Simbrunner ◽  
...  
Keyword(s):  
Thin Films ◽  
Critical Angle ◽  
Grazing Incidence ◽  
X Rays ◽  
Organic Thin Film ◽  
X Ray Diffraction ◽  
Reliable Determination ◽  
X Ray ◽  
Out Of Plane

Dynamical scattering effects are observed in grazing-incidence X-ray diffraction experiments using an organic thin film of 2,2′:6′,2′′-ternaphthalene grown on oxidized silicon as substrate. Here, a splitting of all Bragg peaks in the out-of-plane direction (z-direction) has been observed, the magnitude of which depends both on the incidence angle of the primary beam and the out-of-plane angle of the scattered beam. The incident angle was varied between 0.09° and 0.25° for synchrotron radiation of 10.5 keV. This study reveals comparable intensities of the split peaks with a maximum for incidence angles close to the critical angle of total external reflection of the substrate. This observation is rationalized by two different scattering pathways resulting in diffraction peaks at different positions at the detector. In order to minimize the splitting, the data suggest either using incident angles well below the critical angle of total reflection or angles well above, which sufficiently attenuates the contributions from the second scattering path. This study highlights that the refraction of X-rays in (organic) thin films has to be corrected accordingly to allow for the determination of peak positions with sufficient accuracy. Based thereon, a reliable determination of the lattice constants becomes feasible, which is required for crystallographic structure solutions from thin films.

Near-Surface Chemical Characterization Using Grazing Incidence X-ray Fluorescence

1989 ◽  
Vol 33 ◽  
pp. 205-211 ◽  
Author(s):  
Kenji Sakurai ◽  
Atsuo lida
Keyword(s):  
Chemical Characterization ◽  
Grazing Incidence ◽  
Total Reflection ◽  
Surface Element ◽  
X Rays ◽  
Fluorescence Technique ◽  
Element Analysis ◽  
Near Surface ◽  
X Ray ◽  
Glancing Angle

External X-ray total reflection occurs when collimated X-ray beams impinge on a smooth, flat surface of matter at a small glancing angle, typically a few mrad. With respect to the X-ray fluorescence technique, total reflection experiments have allowed the trace determination of solution samples using an X-ray mirror as a sample support. The grazing incidence X-ray fluorescence technique (GIF) is also suitable for near-surface element analysis of the material, because the penetration depth of X-rays is 10-1000 Å around the critical angle.

scholarly journals Application of X-rays Diffraction for Identifying Thin Oxide Surface Layers on Zinc Coatings

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1005
Author(s):  
George Vourlias
Keyword(s):  
Grazing Incidence ◽  
Oxide Surface ◽  
Zinc Oxide Film ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thin Oxide Films ◽  
Thin Oxide ◽  
Predicted Values ◽  
Zinc Coatings

Structural characterization of compound material coatings is usually achieved using time-consuming and destructive techniques such as optical and electrical microscopy, which require the use of grinding processes not always compatible with the material. This paper reports on the effective use of a theoretical model based on X-ray diffraction to calculate the thickness and composition of thin oxide films formed on the surface of zinc coatings. Zinc coatings are widely used in industrial application as protective layers against the atmospheric corrosion of steel substrates. The thickness of single- and multi-layer coatings is estimated using grazing incidence X-ray diffraction and various incidence angles. The coatings were grown using hot-dip, pack cementation and thermal spray techniques, and their experimental characteristics were compared to the theoretically predicted values of thickness and composition. The results indicate the formation of a thin zinc oxide film on top of each coating, which acts as an isolation layer and protects the surface of the sample against the environmental corrosion. Finally, the penetration depth of the X-rays into the zinc-based coatings for grazing incidence and Bragg–Brentano X-ray diffraction geometries were calculated using theoretical equations and experimentally confirmed.

Micro X-ray diffraction analysis of thin films using grazing-exit conditions

1998 ◽  
Vol 5 (3) ◽  
pp. 902-904 ◽  
Author(s):  
Takashi Noma ◽  
Atsuo Iida
Keyword(s):  
Sample Surface ◽  
Exit Angle ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Sensitivity ◽  
Refraction Effect ◽  
Glancing Angle ◽  
Diffraction Patterns ◽  
Focused Beam

An X-ray diffraction technique using a hard X-ray microbeam for thin-film analysis has been developed. To optimize the spatial resolution and the surface sensitivity, the X-ray microbeam strikes the sample surface at a large glancing angle while the diffracted X-ray signal is detected with a small (grazing) exit angle. Kirkpatrick–Baez optics developed at the Photon Factory were used, in combination with a multilayer monochromator, for focusing X-rays. The focused beam size was about 10 × 10 µm. X-ray diffraction patterns of Pd, Pt and their layered structure were measured. Using a small exit angle, the signal-to-background ratio was improved due to a shallow escape depth. Under the grazing-exit condition, the refraction effect of diffracted X-rays was observed, indicating the possibility of surface sensitivity.

X-ray Scattering from Interfaces

1991 ◽  
Vol 237 ◽  
Author(s):  
E. Vlieg ◽  
H. A. Van Der Vegt
Keyword(s):  
Epitaxial Growth ◽  
Surface Structures ◽  
X Rays ◽  
X Ray Diffraction ◽  
General Outline ◽  
X Ray ◽  
Buried Interfaces ◽  
X Ray Scattering ◽  
High Penetration

ABSTRACTX-ray diffraction has found an increasing use in the characterization of surface structures. Due to the high penetration depth of X-rays, the technique is also very suitable for the study of buried interfaces. We will give a general outline of the technique, and then discuss two examples concerning epitaxial growth.

Surface and Interface Strains Studied by X-Ray Diffraction

1997 ◽  
Vol 505 ◽  
Author(s):  
Koichi. Akimoto ◽  
Takashi Emoto ◽  
Ayahiko Ichimiya
Keyword(s):  
Silicon Substrate ◽  
Silicon Oxide ◽  
Incident Angle ◽  
Surface Strain ◽  
Native Oxide ◽  
X Rays ◽  
X Ray Diffraction ◽  
Strain Fields ◽  
X Ray ◽  
Surface And Interface

ABSTRACTWe have developed a technique of X-ray diffraction in order to measure strain fields near semiconductor surface and interface. The diffraction geometry is using the extremely asymmetric Bragg-case bulk reflection of a small incident angle to the surface and a large angle exiting from the surface. The incident angle of the X-rays is set near critical angle of total reflection by tuning X-ray energy of synchrotron radiation at the Photon Factory, Japan. For thermally grown-silicon oxide/Si(100) interface, the X-ray intensity of the silicon substrate 311 reflection has been measured. From comparison of the full width at half maxima (FWHM) of X-ray rocking curves of various thickness of silicon oxides, it has been revealed that silicon substrate lattice is highly strained in the thin ( less than about 5 nm) silicon oxide/silicon system. In order to know the original silicon surface strain, we have also performed the same kind measurements in the ultra-high vacuum chamber. A clean Si(l 11) 7×7 surface gives sharper X-ray diffraction peak than that of the native oxide/Si(l 11) system. From these measurements, it is concluded that the thin silicon oxide film itself gives strong strain fields to the silicon substrates, which may be the reason of the existence of the structural transition layer at the silicon oxide/Si interface.

SURFACE AND INTERFACE STRAINS REVEALED BY X-RAY DIFFRACTION

1999 ◽  
Vol 06 (06) ◽  
pp. 963-966 ◽  
Author(s):  
KOICHI AKIMOTO ◽  
TAKASHI EMOTO ◽  
YUYA ISHIKAWA ◽  
AYAHIKO ICHIMIYA
Keyword(s):  
Silicon Substrate ◽  
Strain Field ◽  
Theoretical Calculations ◽  
Incident Angle ◽  
Experimental Results ◽  
Lattice Expansion ◽  
X Rays ◽  
X Ray Diffraction ◽  
Strain Fields ◽  
X Ray

We measured strain fields near semiconductor surface by X-ray diffraction. The diffraction geometry was using the extremely asymmetric Bragg-case bulk reflection of a small incident angle to the surface and a large angle exiting from the surface. The incident angle of the X-rays was set near critical angle of total reflection by tuning X-ray energy of synchrotron radiation. The X-ray intensity of the silicon substrate 311 reflection was measured to study a Si(111) surface in the ultrahigh vacuum chamber. A clean Si (111)-(7 × 7) surface was found to give a sharper X-ray diffraction peak than that of the native oxide/Si(111) system. By comparison of experimental results and theoretical calculations, it was concluded that the thin silicon oxide film itself gives strong strain fields to the silicon substrates of lattice expansion toward the [311] direction. The strain fields at the Al- and Ag- induced [Formula: see text] surface reconstruction on the Si(111) substrate were also measured. By comparison of experimental results and theoretical calculations, Al-induced reconstruction was suggested to give a strain field to the silicon substrate of lattice expansion toward the [311] direction, whereas Ag-induced reconstruction was suggested to give a strain field to the silicon substrate of lattice compression toward the [311] direction.

X-ray diffraction properties of curved crystal diffractors

1992 ◽  
Vol 50 (2) ◽  
pp. 1734-1735
Author(s):  
W. Z. Chang ◽  
D. B. Wittry
Keyword(s):  
Diffraction Theory ◽  
X Rays ◽  
Diffraction Image ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Bent Crystal ◽  
Diffraction Geometry ◽  
Crystal Parameter ◽  
Quantitative Procedure

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.

Contribution of x-ray total reflection to the background intensity in EPMA

1990 ◽  
Vol 48 (2) ◽  
pp. 202-203
Author(s):  
Werner P. Rehbach ◽  
Peter Karduck
Keyword(s):  
Atomic Number ◽  
Target Material ◽  
Total Reflection ◽  
Background Intensity ◽  
X Rays ◽  
Characteristic Radiation ◽  
X Ray

In the EPMA of soft x rays anomalies in the background are found for several elements. In the literature extremely high backgrounds in the region of the OKα line are reported for C, Al, Si, Mo, and Zr. We found the same effect also for Boron (Fig. 1). For small glancing angles θ, the background measured using a LdSte crystal is significantly higher for B compared with BN and C, although the latter are of higher atomic number. It would be expected, that , characteristic radiation missing, the background IB (bremsstrahlung) is proportional Zn by variation of the atomic number of the target material. According to Kramers n has the value of unity, whereas Rao-Sahib and Wittry proposed values between 1.12 and 1.38 , depending on Z, E and Eo. In all cases IB should increase with increasing atomic number Z. The measured values are in discrepancy with the expected ones.

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