Diffuse scattering from interface roughness in grazing-incidence x-ray diffraction

1996 ◽  
Vol 54 (11) ◽  
pp. 8150-8162 ◽  
Author(s):  
S. A. Stepanov ◽  
E. A. Kondrashkina ◽  
M. Schmidbauer ◽  
R. Köhler ◽  
J.-U. Pfeiffer ◽  
...  
Keyword(s):  
Diffuse Scattering ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
X Ray Diffraction ◽  
X Ray

Evolution of Interfacial Roughness Correlations of Fe Au Films Grown on Mgo(001) Substrates

1996 ◽  
Vol 440 ◽  
Author(s):  
P. C. Chow ◽  
R. Paniago ◽  
R. Forrest ◽  
S. C. Moss ◽  
S. S. P. Parkin ◽  
...  
Keyword(s):  
Thin Films ◽  
Diffuse Scattering ◽  
Perfect Match ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
Metallic Structures ◽  
X Ray ◽  
Dimensional Image ◽  
X Ray Scattering ◽  
Image Plate Detector

AbstractThe growth by sputtering of a series of thin films of Fe/Au on MgO(001) substrates was analyzed using Bragg and diffuse X-ray scattering. The Fe (bcc) layer grows rotated by 45° with respect to the MgO – Au(fcc) (001) epitaxial orientation, resulting in an almost perfect match between the two metallic structures. By collecting the X-ray diffuse scattering under grazing incidence using a 2-dimensional image plate detector, we mapped the reciprocal space of these films. We characterized the correlated interface roughness starting with a buffer of Fe in which only three interfaces are present. The propagation of the roughness was subsequently characterized for Fe/Au multilayers with 40 and 100 bilayers. We observe an enlargement of the surface features as a function of time, evidenced by the longer lateral cutoff length measured for thicker films.

Thermal Degradation of SiGe Interfaces Studied by X-Ray Reflectivity and Diffraction

1991 ◽  
Vol 239 ◽  
Author(s):  
J. M. Hudson ◽  
A. R. Powell ◽  
D. K. Bowen ◽  
M. Wormington ◽  
B. K. Tanner ◽  
...  
Keyword(s):  
Short Range ◽  
Grazing Incidence ◽  
Sige Layer ◽  
Interface Roughness ◽  
Total Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface And Interface ◽  
Superlattice Structures

ABSTRACTWe demonstrate the use of x-ray diffraction to provide accurate compositional information, together with grazing incidence reflectivity to provide information on layer thicknesses and surface and interface roughnesses, on Si/Si1-xGex superlattice structures of less than 200nm total thickness.The quality of SiGe interfaces has been investigated in superlattices where x varies from 0.1 to 0.5. At low Ge compositions the interfaces are shown to be smooth to a few angstroms. However, as the Ge composition in the SiGe layer approaches 50%, severe roughness is observed at the SiGe to Si interfaces, although the Si to SiGe interfaces remain relatively smooth.Upon annealing for one hour at 850°C the Ge diffuses outwards from the SiGe layers and can be closely modelled by inclusion of a (2.4±0.3)nm linearly graded layer either side of the SiGe layer into a simulation program. The long range roughness at the SiGe to Si interface is lost upon annealing leaving only a short range roughness of similar size to the Si to SiGe interface roughness.Reflectivity measurements have been shown to distinguish between interface roughness and interdiffusion for the annealed system.

scholarly journals Interface Evolution in a W/Si Multilayer after Rapid Thermal Annealing Studied by X-ray Reflectivity and Diffuse Scattering

1997 ◽  
Vol 30 (5) ◽  
pp. 642-646 ◽  
Author(s):  
M. Jergel ◽  
V. Holý ◽  
E. Majková ◽  
S. Luby ◽  
R. Senderák
Keyword(s):  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Diffuse Scattering ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
X Rays ◽  
Interface Evolution ◽  
X Ray ◽  
Scattering Measurements ◽  
Highly Correlated

An interface study of the effect of rapid thermal annealing (RTA) in the temperature range 523–1273 K for 5–40 s on a nominally [(50 Å Si/10 Å W) × 9] amorphous multilayer (ML) deposited on an Si(100) wafer was performed by X-ray reflectivity and diffuse-scattering measurements at grazing incidence. The results of the X-ray reflectivity and diffuse-scattering measurements were evaluated by Fresnel optical computational code and within the distorted-wave Born approximation, respectively. Up to the 773 K/5 s annealing step, the r.m.s. interface roughness decreases by 30%, which brings about a reflectivity increase of 20% on the first Bragg maximum. There is a small overall increase of the r.m.s. interface roughness across the ML in the as-deposited state and the interface profiles are highly correlated. From the very beginning of RTA, the fractal interface behaviour is gradually lost and the lateral correlation length increases, this process being accompanied by a decrease of the interface conformality. This tendency continues during the 773 K/20 s annealing; however, the r.m.s. roughness evolution is reversed. During the 1023 K/5 s annealing, the interfaces are no longer `seen' by the X-rays and, during the 1273 K/5 s annealing, a total collapse of the ML structure takes place.

X-Ray Diffraction Study of the Phase Transition of the ${\rm Si}(111)(\sqrt{3} \times \sqrt{3})\mbox{-Ag}$ Surface

2003 ◽  
Vol 10 (02n03) ◽  
pp. 519-524 ◽  
Author(s):  
Toshio Takahashi ◽  
Hiroo Tajiri ◽  
Kazushi Sumitani ◽  
Koichi Akimoto ◽  
Hiroshi Sugiyama ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Low Temperatures ◽  
Diffuse Scattering ◽  
Room Temperature ◽  
Bragg Reflection ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Displacive Phase Transition

The structure of the [Formula: see text] surface was studied at both room temperature and a low temperature of 50 K using grazing incidence X-ray diffraction. At low temperatures diffuse scattering was observed in addition to Bragg reflection. Least squares analyses for Bragg reflections using anisotropic Debye–Waller factors show that the structure at 50 K is consistent with an inequivalent triangle (IET) model, while the structure at room temperature is explained by a honeycomb-chained triangle (HCT) model with strong anisotropic Debye–Waller factors. From the temperature dependence of diffuse scattering, the phase transition temperature Tc and critical exponent β were determined to be about 150 K and 0.27. Some Bragg intensities showed discontinuous changes in their first derivatives at Tc. The results favor a displacive phase transition rather than an order–disorder one.

Structural Characterization of Epitaxial Si / Pr2O3 / Si(111) Heterostructures

2005 ◽  
Vol 108-109 ◽  
pp. 741-748 ◽  
Author(s):  
P. Zaumseil ◽  
T. Schroeder ◽  
G. Weidner
Keyword(s):  
Structural Characterization ◽  
Hexagonal Phase ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Perfection ◽  
Transmission Electron ◽  
Control Layer

The use of heteroepitaxial Si / Pr2O3 / Si(111) systems as semiconductor-insulatorsemiconductor (SIS) stacks in future applications requires a detailed structural characterization. We used X-ray reflectivity (XRR) to control layer thickness and interface roughness, standard X-ray diffraction (XRD) to analyze the Pr2O3 phase, orientation and crystal perfection, and grazing incidence XRD to study the thin epitaxial Si top layer. Transmission electron microscopy (TEM) was used to prove the results by direct imaging on a microscopic scale. Pr2O3 grows epitaxially in its hexagonal phase and (0001) orientation on Si(111) substrates. An epitaxial Si overgrowth in (111) orientation and good perfection is possible, but such Si layers exhibit two stacking twins, one with the same in-plane orientation as the substrate and one rotated by 180° around the Si [111] direction.

X-Ray Reflection, A New Tool for Investigating Layered Structures and Interfaces

1991 ◽  
Vol 35 (A) ◽  
pp. 127-135 ◽  
Author(s):  
Bruno Lengeler
Keyword(s):  
Angular Dependence ◽  
Diffuse Scattering ◽  
Specular Reflection ◽  
Condensed Matter ◽  
Grazing Incidence ◽  
Total Reflection ◽  
Interface Roughness ◽  
X Rays ◽  
X Ray ◽  
X Ray Absorption

AbstractAt grazing incidence all X-ray techniques become surface sensitive. Far below the angle of total reflection the X-rays penetrate only 20 to 70 Å into condensed matter. X-ray reflectivity measurements give the density and the thickness of layers on substrates and the roughness of external and internal interfaces. The diffuse scattering in the vicinity of the specular reflection gives, besides the interface roughness, also the height-height correlation of the surface. From the angular dependence of the fluorescence intensity, emitted as a consequence of X-ray absorption, the depth profile of the absorbing species can be deduced. Artificial periodic multilayers give rise to Bragg reflexes and to standing X-ray wave fields, the angular dependence of which give the distribution of atomic species in the periodic stack. A number of examples illustrate the possibilities of the technique.

Grazing incidence x-ray diffraction at free-standing nanoscale islands: fine structure of diffuse scattering

2003 ◽  
Vol 36 (10A) ◽  
pp. A225-A230 ◽  
Author(s):  
D Grigoriev ◽  
M Hanke ◽  
M Schmidbauer ◽  
P Sch fer ◽  
O Konovalov ◽  
...  
Keyword(s):  
Fine Structure ◽  
Diffuse Scattering ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray

Grazing Incidence X-Ray Reflectometry Studies of Cadmium Arachidate Langmuir-Blodgett Films

1991 ◽  
Vol 237 ◽  
Author(s):  
B. K. Tanner ◽  
D. K Bowen ◽  
M. C Petty ◽  
S. Swaminathan ◽  
F. Granfeld
Keyword(s):  
Molecular Layer ◽  
Grazing Incidence ◽  
Interface Roughness ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Langmuir Blodgett ◽  
Crystal Imperfections ◽  
Langmuir Blodgett Films ◽  
Good Agreement

ABSTRACTGrazing incidence X-ray reflectometry has been used to characterize Langmuir-Blodgett films of cadmium arachidate deposited on silicon substrates. The agreement between layer parameters deduced from the interference fringe period and low angle Bragg peak positions was excellent. Good agreement was found between experimental and simulated reflectivity profiles only when interface roughness and a varying molecular layer thickness was included. Inclusion of interface roughness alone results in a substantial enhancement in the intensity of the Bragg peaks. This effect is identified as being equivalent to the reduction in extinction found in classical X-ray diffraction due to crystal imperfections.

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