Measurement of the Lateral Periodicity of a Quantum Dot Array by Triple Crystal Diffractometry

1993 ◽  
Vol 312 ◽  
Author(s):  
B. Jenichen ◽  
K. Ploog ◽  
O. Brandt
Keyword(s):  
Quantum Dot ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Inas Quantum Dots ◽  
Rocking Curve ◽  
X Ray ◽  
Gaas Matrix ◽  
Scattering Factor ◽  
Inas Quantum Dot ◽  
Kinematical Theory

AbstractThe lateral periodicity of an InAs quantum dot array in a GaAs matrix is measured in the differential rocking curve by triple crystal diffractometry. The quantum dot array was grown by molecular beam epitaxy of submonolayer InAs films on a terraced (001) GaAs substrate. The x-ray diffraction of the array is described in the limits of the kinematical theory. Both the changes in the scattering factor and the tetragonal deformations due to the InAs quantum dots are taken into account. The lateral periodicity of the array along [100] is 8–11nm dependent on the position of the measured region compared with an average of 10nm obtained from the miscut of the sample. In addition the vertical periodicity of the array is measured by comparison of the double crystal rocking curve with the corresponding simulation in the dynamical approximation. The vertical period of the array along [001] is 26.5nm. The coverage of the submonolayer InAs films estimated from the same measurement is 0.4. The absence of plastic relaxation is confirmed by x-ray topography.

TEM Study of the Morphology Of GaN/SiC (0001) Grown at Various Temperatures by MBE

1999 ◽  
Vol 595 ◽  
Author(s):  
W.L. Sarney ◽  
L. Salamanca-Riba ◽  
V. Ramachandran ◽  
R.M Feenstra ◽  
D.W. Greve
Keyword(s):  
Low Temperatures ◽  
Stacking Faults ◽  
Full Width ◽  
X Ray Diffraction ◽  
High Quality ◽  
Double Crystal ◽  
Tem Analysis ◽  
Rocking Curve ◽  
X Ray ◽  
Substrate Temperatures

AbstractGaN films grown on SiC (0001) by MBE at various substrate temperatures (600° - 750° C) were characterized by RHEED, STM, x-ray diffraction, AFM and TEM. This work focuses on the TEM analysis of the films' features, such as stacking faults and dislocations, which are related to the substrate temperature. There are several basal plane stacking faults in the form of cubic inclusions for samples grown at low temperatures compared to those grown at high temperatures. The dislocation density is greatest for the film grown at 600°C, and it steadily decreases with increasing growth temperatures. Despite the presence of various defects, x-ray analysis shows that the GaN films are of high quality. The double crystal rocking curve full width at half maximum (FWHM) for the GaN (0002) peak is less than 2 arc-minutes for all of the films we measured and it decreases with increasing growth temperature.

CdTe Films Grown on InSb Substrates by Organometallic Epitaxy

1986 ◽  
Vol 90 ◽  
Author(s):  
I. B. Bhat ◽  
N. R. Taskar ◽  
J. Ayers ◽  
K. Patel ◽  
S. K. Ghandhi
Keyword(s):  
Secondary Ion Mass Spectrometry ◽  
Organometallic Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Cdte Films ◽  
Secondary Ion ◽  
Cdte Growth

ABSTRACTCadmium telluride layers were grown on InSb substrates by organometallic vapor phase epitaxy and examined using secondary ion mass spectrometry (SIMS), photoluminescence (Pb) and double crystal x-ray diffraction (DCD). The substrate temperature and the nature of the surface prior to growth are shown to be the most important parameters which influence the quality of CdTe layers. Growth on diethyltelluride (DETe) stabilized InSb substrates resulted in CdTe growth with a misorientation of about 4 minutes of arc with respect to the substrates. On the other hand, the grown layers followed the orientation of the substrates when a dimethylcadmium (DMCd) stabilized InSb was used. Growth at 350°C resulted in the smallest x-ray rocking curve (DCRC) full width at half maximum (FWHM) of about 20 arc seconds.

High Resolution Digital X-Ray Rocking Curve Topography

1986 ◽  
Vol 30 ◽  
pp. 527-535 ◽  
Author(s):  
T.S. Ananthanarayanan ◽  
W.E. Mayo ◽  
R.G. Rosemeier
Keyword(s):  
Defect Structure ◽  
Semiconductor Device ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
Crystalline Materials ◽  
Digital Implementation ◽  
X Ray ◽  
Rapid Characterization ◽  
Non Destructive

AbstractThis study presents a unique and novel enhancement of the double crystal diffractometer which allows topographic mapping of X-ray diffraction rocking curve half widths at about 100-150μm spatial resolution. This technique can be very effectively utilized to map micro-lattice strain fields in crystalline materials. The current focus will be on the application of a recently developed digital implementation for the rapid characterization of defect structure and distribution in various semiconductor materials.Digital Automated Rocking Curve (DARC) topography has been successfully applied for characterizing defect structure in materials such as: GaAs, Si, AlGaAs, HgMnTe, HgCdTe, CdTe, Al, Inconnel, Steels, BaF2 PbS, PbSe, etc. The non-intrusive (non- contact & non-destructive) nature of the DARC technique allows its use in studing several phenomena such as corrosion fatigue, recrystallization, grain growth, etc., in situ. DARC topography has been used for isolating regions of non-uniform dislocation density on various materials. It is envisioned that this highly sophisticated, yet simple to operate, system will improve semiconductor-device yield significantly.The high strain sensitivity of the technique results from combination of the highly monochromated and collimated X-ray probe beani, the State of the art linear position-sensitive detector (LPSD) and the high-precision specimen goniometer.

Thickness Measurement of Epitaxical Thin Films by X-ray Diffraction Method

1988 ◽  
Vol 32 ◽  
pp. 279-284
Author(s):  
J. Chaudhuri ◽  
S. Shah ◽  
J.P. Harbison
Keyword(s):  
Thin Films ◽  
Molecular Beam ◽  
Electronic Materials ◽  
Diffraction Method ◽  
Thickness Measurement ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Kinematical Theory ◽  
Double Crystal Diffractometer

AbstractA method was described for determining the thickness of epitaxical thin films common to electronic materials. The equations were developed based on the kinematical theory of X-ray diffraction and effects of both primary and secondary extinctions were considered. As an example of the applications of this method, thickness measurement of AlGaAs thin films on GaAs was demonstrated. These films were grown by molecular beam epitaxy. The integrated reflected intensities from the film and the substrate were obtained by the X-ray double crystal diffractometer. An excellent agreement was obtained between the results from X-ray measurements and RHEED oscillation data.

X-Ray Rocking Curve Analysis of S-Implanted GaAs

1988 ◽  
Vol 126 ◽  
Author(s):  
M. Fatemi ◽  
P.E. Thompson ◽  
J. Chaudhuri ◽  
S. Shah
Keyword(s):  
Thin Film ◽  
Curve Analysis ◽  
Maximum Strain ◽  
Major Peak ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Positive Strain ◽  
Two Peaks

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.

{224} Plane X-Ray Diffraction Study of GaAs on Si Wafers Using a Conventional Double Crystal Diffractometer

1987 ◽  
Vol 91 ◽  
Author(s):  
J.W. Lee ◽  
D.K. Bowen ◽  
J.P. Salerno
Keyword(s):  
Incident Angle ◽  
Wafer Surface ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Near Surface ◽  
Rocking Curve ◽  
X Ray ◽  
Gaas On Si ◽  
Plane Diffraction

ABSTRACTIn an effort to evaluate the near surface crystal quality of GaAs on Si wafers, {224} plane diffraction were investigated using a conventional double crystal x-ray diffractometer without any high intensity radiation source. The x-ray incident angle to wafer surface varied from 3.6 to 9.6 degrees for different {224} planes due to the substrate tilt angle of 3 degrees. The GaAs to Si rocking curve intensity ratio increased significantly as the incident angle decreased. For the diffraction with 3.6 degree incident angle, only the GaAs peak was detected from the 3.5 um thick GaAs on Si wafer and the GaAs peak became narrower. These indicates that this conventional x-ray diffraction technique is applicable for the near surface quality evaluation of GaAs on Si wafers.

Double crystal X-ray diffraction study of MBE self-organized InAs quantum dots

1998 ◽  
Vol 41 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Yutian Wang ◽  
Yan Zhuang ◽  
Wenquan Ma ◽  
Wei Wang ◽  
Xiaoping Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Inas Quantum Dots ◽  
X Ray ◽  
Self Organized

scholarly journals A Vertically Rotating Double-Crystal X-Ray Spectrometer

1963 ◽  
Vol 7 ◽  
pp. 265-280 ◽  
Author(s):  
M. C. Wittels ◽  
F. A. Sherrill ◽  
A. C. Kimbrough
Keyword(s):  
Precise Measurement ◽  
Diffraction Line ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Rocking Curve ◽  
X Ray ◽  
Line Widths

AbstractA versatile double-crystal X-ray spectrometer has been developed for the precise measurement of X-ray diffraction line widths to tenths of seconds. The device can be employed in either the parallel or antiparallel arrangement for rocking curve studies and can also be used in anomalous X-ray transmission experiments with nearly perfect crystals.A detailed description of the instrument is given as well as some results concerning the Darwin theory of X-ray diffraction line widths and Borrmann effects.

Orientation Dependence of CdTe/Si Grown by MBE

1995 ◽  
Vol 399 ◽  
Author(s):  
L. A. Almeida ◽  
Y. P. Chen ◽  
J. P. Faurie ◽  
David J. Smith ◽  
S.-C. Y. Tsen ◽  
...  
Keyword(s):  
Growth Conditions ◽  
Orientation Dependence ◽  
Structural Defects ◽  
X Ray Diffraction ◽  
Substrate Preparation ◽  
Double Crystal ◽  
Interface Quality ◽  
Rocking Curve ◽  
X Ray ◽  
Transmission Electron

ABSTRACTIn this study CdTe (111)B was grown by molecular beam epitaxy on vicinal Si(001) substrates, with a variety of substrate tilt angles (θ), and tilt directions (φ) relative to [110]. Layer quality, and content of double-domain and microtwin defects were evaluated by double crystal rocking curve (DCRC) full width at half maximum (FWHM) and x-ray diffraction, respectively. Transmission electron microscopy (TEM) was used to study interface quality and the nature of structural defects as a function of epilayer thickness. In the present investigation, substrate preparation and growth conditions, particularly initiation conditions, are correlated with Si (001) tilt. It has been found that oxide desorption processes can depend strongly on θ, especially for larger values of θ (> 4°). Currently, we routinely produce single domain, twin-free CdTe(111)B epilayers on vicinal Si (001) substrates.

Microanalysis of Self-assembled InAs Quantum Dot Structures Grown for Infrared Detector Applications

2003 ◽  
Vol 794 ◽  
Author(s):  
W.L. Sarney ◽  
J.W. Little ◽  
S. Svensson
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Infrared Detector ◽  
Single Layer ◽  
Far Infrared ◽  
Mbe Growth ◽  
Inas Quantum Dots ◽  
Gaas Matrix ◽  
Inas Quantum Dot ◽  
Vertical Height

ABSTRACTIn an effort to develop materials that are sensitive to mid and far infrared radiation, we examine InAs quantum dot/GaAs matrix multilayer structures grown by molecular beam epitaxy (MBE). Customized electrical and optical properties result from nanoscale-level manipulation of the dots' physical dimensions. The MBE growth temperature can be set to yield dots having the desired lateral dimension; however this leads to dots of insufficient vertical height. It is therefore necessary to grow the dots in a manner that allows independent control of the lateral and vertical dimensions. In this experiment, the vertical dimension is controlled by growing the dots in a multilayer structure with GaAs matrix layers. An initial layer of InAs quantum dots was grown on top of GaAs, followed by a few seconds short growth of GaAs, and then followed by the growth of another layer of InAs dots. The GaAs laterally surrounds, but does not bury, the InAs quantum dots. When the second layer of InAs dots is grown, they tend to self-organize directly on top of the exposed first layer of dots. We then grew a third layer of dots in the same manner. This effectively results in a pseudo-single layer of dots of the desired height which is then completely buried in GaAs. The goal is to develop structures that can be integrated into high operating temperature quantum dot infrared detectors (QDIPs) that have maximum sensitivity, robustness, and portability.

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