Lattice Strain from Holes in Heavily Doped Si:Ga

1989 ◽  
Vol 147 ◽  
Author(s):  
K. L. Kavanagh ◽  
G. S. Cargill ◽  
R. F. Boehme ◽  
J. C. P. Chang
Keyword(s):  
Experimental Error ◽  
Laser Annealing ◽  
Lattice Strain ◽  
Nearest Neighbor ◽  
X Ray Diffraction ◽  
Lattice Contraction ◽  
Double Crystal ◽  
X Ray ◽  
Heavily Doped ◽  
X Ray Absorption

AbstractHeavily doped Si:Ga has been prepared by liquid phase epitaxy (LPE) and by ionimplantation with rapid thermal annealing (RTA) or laser annealing (LA). Peak substitutional Ga concentrations obtained by each technique were 1.5, 2.5 and 2.9 ×1020cm-3, respectively. Substitutional fractions (>90%) were similar in the three types of samples, and the conductivity scaled with the total Ga concentration. A lattice expansion per substitutional Ga atom in Si of +0.9 ± 0. l×10-24cm3 /atom was measured by double crystal x-ray diffraction. The average nearest neighbor Si-Ga bond length measured with extended x-ray absorption fine structure (EXAFS) was 0.237 ± 0.004 nm, indistinguishable, to within experimental error, from the intrinsic Si-Si bond lngth, 0.235 nm. Combining these two results the lattice strain per hole in the Si valence band was calculated, +0.4 ± 0.8x10G-cm3. This result complements the lattice contraction per electron in the Si conduction band (-1.8 ± 0.4x10-24cm 3) already reported for Si:As [G. S. Cargill III, J. Angilelloand K. L. Kavanagh, Phys. Rev. Letters 61, 1748 (1988)].

EFFECT OF HEAT TREATMENT ON MICROSTRUCTURE AND MAGNETOSTRICTIVE PROPERTY OF MELT-SPUN Fe85Ga15 RIBBONS

2013 ◽  
Vol 27 (30) ◽  
pp. 1350174 ◽  
Author(s):  
HAO LIU ◽  
HAIOU WANG ◽  
MENGXIONG CAO ◽  
WEISHI TAN ◽  
YANGGUANG SHI ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fine Structure ◽  
High Resolution ◽  
Nearest Neighbor ◽  
Annealed Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Absorption Fine ◽  
Melt Spun ◽  
X Ray Absorption

In order to study the microstructure of Fe – Ga alloy, Fe 85 Ga 15 ribbons prepared with different wheel velocity were studied by high resolution X-ray diffraction (HRXRD) and extend X-ray absorption fine structure (EXAFS). HRXRD patterns showed that only disordered A 2 phase was observed in as-cast Fe 85 Ga 15 alloy. A modified- DO 3 phase was detected in all of the melt spun samples. The HRXRD associated with EXAFS results indicated that Ga atoms were located as second-nearest neighbor along [100] orientation. A little DO 3 phase was found in ribbons annealed at 1000°C under 0.06 MPa Ar atmosphere. The result of magnetostriction measurement revealed that in the ribbon prepared with higher wheel velocity, more modified- DO 3 phase will enhance the magnetostriction. DO 3 phase in the annealed sample will deteriorate the magnetostrictive properties of Fe – Ga ribbons.

Effects of Rapid Thermal Anneals on Boron Implanted GaAs

1988 ◽  
Vol 144 ◽  
Author(s):  
R. C. Bowman ◽  
P. M. Adams ◽  
M. H. Herman ◽  
S. E. Buttrill
Keyword(s):  
Electron Beam ◽  
Raman Scattering ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Lattice Strain ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
X Ray ◽  
Conventional Furnace

ABSTRACTRaman scattering, double-crystal x-ray diffraction, and electron beam electroreflectance have been used to assess the damage produced in undoped (100)-GaAs by boron ion implants and the influence of post-implant anneals. Both conventional furnace and rapid thermal annealing treatments were found to remove much of the lattice strain created by the implants. However, considerable disorder also remains after these anneals.

Double-Crystal X-ray Diffraction Studies of Si ion-Implanted and Pulsed Laser-Annealed GaAs

1990 ◽  
Vol 34 ◽  
pp. 531-541
Author(s):  
P. M. Adams ◽  
J. F. Knudsen ◽  
R. C. Bowman
Keyword(s):  
Ion Implantation ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Thermal Treatments ◽  
X Ray Diffraction ◽  
Surface Layers ◽  
Double Crystal ◽  
X Ray ◽  
Pulsed Laser Annealing ◽  
Microelectronic Devices

Ion-implantation has many applications in the fabrication and processing of microelectronic devices from semiconductors, but thermal treatments are required to remove defects produced by the implant and to electrically activate dopants. Recently, pulsed laser annealing has been used to activate surface layers of GaAs that have been heavily doped with 28Si+ by ion implantation, and carrier concentrations of > 1 x 1019 cm-3 have been achieved (Ref. 1). Double-crystal x-ray diffraction techniques are very sensitive to strains and defects in single crystals and provide a means for characterizing and quantifying the damage produced by ion-implantation and the subsequent relief of damage by pulsed laser annealing.

X-Ray and Raman Topographic Studies of Gaas Implanted With 28Si+ and Pulsed Laser Annealed

1989 ◽  
Vol 157 ◽  
Author(s):  
R.C. Bowman ◽  
J.F. Knudsen ◽  
P.M. Adams ◽  
H.D. Yao ◽  
A.D. Compaan
Keyword(s):  
Raman Spectroscopy ◽  
Partial Melting ◽  
Lattice Strain ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
Double Crystal ◽  
Dopant Activation ◽  
X Ray ◽  
Incomplete Removal ◽  
Surrounding Areas

ABSTRACTDouble-crystal x-ray diffraction and topography, along with Raman spectroscopy and topography are used to study lattice reconstruction and carrier activation for pulsed laser annealed Si implanted GaAs. Although lattice strain is essentially eliminated, along with the production of carrier concentrations to about 3×1019 cm.3 at the center of laser annealed spots, incomplete removal of implant induced disorder and little dopant activation are observed in surrounding areas. Correlations of Raman and x-ray topographs suggest that concentric regions of partial melting, but without epitaxial regrowth, occur in the periphery of the laser annealed spots.

X-Ray Measurements of Lattice Strain in Doped Epitaxial Silicon

1987 ◽  
Vol 93 ◽  
Author(s):  
A. P. Pogany ◽  
T. E. Preuss
Keyword(s):  
Laser Annealing ◽  
Lattice Strain ◽  
Covalent Radius ◽  
Epitaxial Silicon ◽  
Double Crystal ◽  
Strain Measurements ◽  
Strain Profile ◽  
One Dimensional ◽  
X Ray ◽  
Pulsed Laser Annealing

ABSTRACT(100) silicon amorphized by antimony ion implantation was epitaxially regrown by either furnace or pulsed laser annealing. Rocking curves were measured on a double-crystal X-ray diffractometer, and compared with calculations based on a one-dimensional strain profile. For laser annealed samples the strain profile followed that of the antimony (redistributed by surface melting), with a proportionality constant given by the Pauling covalent radius ratio. For furnace annealed samples however the strain was found to be deeper, but of smaller peak magnitude, than that expected from the antimony distribution. This is attributed to formation and movement of defects acting to relax lattice strain. Other X-ray strain measurements on epitaxial silicon containing other dòpants are briefly reviewed.

Local atomic structure in tetragonal pure ZrO2nanopowders

2010 ◽  
Vol 43 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Leandro M. Acuña ◽  
Diego G. Lamas ◽  
Rodolfo O. Fuentes ◽  
Ismael O. Fábregas ◽  
Márcia C. A. Fantini ◽  
...  
Keyword(s):  
Tetragonal Phase ◽  
Local Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Structures ◽  
Crystallite Sizes ◽  
Exafs Study ◽  
The Difference ◽  
X Ray Absorption ◽  
Good Agreement

The local atomic structures around the Zr atom of pure (undoped) ZrO2nanopowders with different average crystallite sizes, ranging from 7 to 40 nm, have been investigated. The nanopowders were synthesized by different wet-chemical routes, but all exhibit the high-temperature tetragonal phase stabilized at room temperature, as established by synchrotron radiation X-ray diffraction. The extended X-ray absorption fine structure (EXAFS) technique was applied to analyze the local structure around the Zr atoms. Several authors have studied this system using the EXAFS technique without obtaining a good agreement between crystallographic and EXAFS data. In this work, it is shown that the local structure of ZrO2nanopowders can be described by a model consisting of two oxygen subshells (4 + 4 atoms) with different Zr—O distances, in agreement with those independently determined by X-ray diffraction. However, the EXAFS study shows that the second oxygen subshell exhibits a Debye–Waller (DW) parameter much higher than that of the first oxygen subshell, a result that cannot be explained by the crystallographic model accepted for the tetragonal phase of zirconia-based materials. However, as proposed by other authors, the difference in the DW parameters between the two oxygen subshells around the Zr atoms can be explained by the existence of oxygen displacements perpendicular to thezdirection; these mainly affect the second oxygen subshell because of the directional character of the EXAFS DW parameter, in contradiction to the crystallographic value. It is also established that this model is similar to another model having three oxygen subshells, with a 4 + 2 + 2 distribution of atoms, with only one DW parameter for all oxygen subshells. Both models are in good agreement with the crystal structure determined by X-ray diffraction experiments.

The Relative Merits of Oxides of Hafnium, Cerium and Thorium as Surrogates for Plutonium Oxide in Calcium Phosphate Ceramics

2009 ◽  
Vol 1193 ◽  
Author(s):  
B. L. Metcalfe ◽  
S. K. Fong ◽  
L. A. Gerrard ◽  
I. W. Donald ◽  
E. S. Welch ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Calcination Temperature ◽  
Cerium Oxide ◽  
Absorption Spectroscopy ◽  
Hafnium Oxide ◽  
Intermediate Level ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Absorption ◽  
Additional Phase

AbstractThe choice of surrogate for plutonium oxide for use during the initial stages of research into the immobilization of intermediate level pyrochemical wastes containing plutonium andamericium oxides in a calcium phosphate host has been investigated by powder X-ray diffraction and X-ray absorption spectroscopy. Two non-radioactive surrogates, hafnium oxide and cerium oxide, together with radioactive thorium oxide were compared. Similarities in behaviour were observed for all three surrogates when calcined at the lowest temperature, 750°C but differences became more pronounced as the calcination temperature was increased to 950°C. Although some reaction occurred between all the surrogates and the host to form a substituted whitlockite phase, increasing the temperature led to a significant increase in the cerium reaction and the formation of an additional phase, monazite. Additionally it was observed that the cerium became increasingly trivalent at higher temperatures.

Formalism for the determination of intermediate stress gradients using X-ray diffraction

2009 ◽  
Vol 42 (2) ◽  
pp. 192-197 ◽  
Author(s):  
Thomas Gnäupel-Herold
Keyword(s):  
Lattice Strain ◽  
Narrow Line ◽  
X Ray Diffraction ◽  
Beam Spot ◽  
Strain Measurements ◽  
One Dimensional ◽  
X Ray ◽  
Stress Gradients ◽  
Shaped Beam

A method is outlined that allows the determination of one-dimensional stress gradients at length scales greater than 0.2 mm. By using standard four-circle X-ray diffractometer equipment and simple aperture components, length resolutions down to 0.05 mm in one direction can be achieved through constant orientation of a narrow, line-shaped beam spot. Angle calculations are given for the adjustment of goniometer angles, and for the effective azimuth and tilt of the scattering vector for general angle settings in a four-circle goniometer. The latter is necessary for the computation of stresses from lattice strain measurements.

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