Exafs Studies of Ion Implanted Bismuth

1984 ◽  
Vol 41 ◽  
Author(s):  
E. M. Kunoff ◽  
M. S. Dresselhaus ◽  
Y. H. Kao
Keyword(s):  
Ion Implantation ◽  
Point Defects ◽  
Nearest Neighbor ◽  
Local Environment ◽  
Sample Surface ◽  
High Energy ◽  
Synchrotron Source ◽  
Different Temperatures ◽  
Total Fluence ◽  
Nearest Neighbor Distances

AbstractMagnetorefiection and preliminary Rutherford Backscattering channeling experiments indicate that point defects induced in the bismuth lattice by ion implantation are largely annealed out during the implantation process due to its low melting temperature of 271.3°C. These experiments also show that the implanted ions cause long range strains in the crystal. Single crystal bismuth samples have been implanted at low temperatures (from 273°K down to 77°K) with 75 As to a total fluence of 5 × 1016/cm2 at energies ranging from 50 keV to 200 keV to yield an approximately constant arsenic profile from the sample surface to a depth of 625 Å. To study the local environment of the implanted As ions, EXAFS measurements have been made at the Cornell High Energy Synchrotron Source (CHESS). From these data, we obtain a comparison of the As nearest neighbor distances in samples implanted at different temperatures. We discuss the effect of sample temperature during implantation on these properties. This work represents the first use of EXAFS to characterize annealing of implantation-induced lattice defects during the process of ion implantation.

Determining the Ratio of the Precipitated versus Substituted Arsenic by XAFS and SIMS in Heavy Dose Arsenic Implants in Silicon

2001 ◽  
Vol 669 ◽  
Author(s):  
M. A. Sahiner ◽  
S. W. Novak ◽  
J. C. Woicik ◽  
J. Liu ◽  
V. Krishnamoorty
Keyword(s):  
Solid Solubility ◽  
Amorphous Materials ◽  
Nearest Neighbor ◽  
Secondary Ion Mass Spectrometry ◽  
Local Environment ◽  
Coordination Numbers ◽  
Annealing Conditions ◽  
X Ray Absorption ◽  
Secondary Ion ◽  
Nearest Neighbor Distances

ABSTRACTDoping silicon with arsenic by ion implantation above the solid solubility level leads to As clusters and/or precipitates in the form of monoclinic SiAs causing electrical deactivation of the dopant. Information on the local structure around the As atom, and the As concentration depth profiles is important for the implantation and annealing process in order to reduce the precipitated As and maximize the electrically activated As. In this study, we determined the local As structure and the precipitated versus substituted As for As implants in CZ (001) Si wafers, with implant energies between 20 keV and 100 keV, and implant doses ranging from 1 × 1015/cm2 to 1 × 1018/cm2. The samples were subjected to different thermal annealing conditions. We used secondary ion mass spectrometry (SIMS) and UT- MARLOWE simulations to determine the region where the As-concentration is above the solid solubility level. By x-ray absorption fine structure spectroscopy (XAFS), we probed the structure of the local environment around As. XAFS being capable of probing the short-range order in crystalline and amorphous materials provides information on the number, distance and chemical identity of the neighbors of the main absorbing atom. Using Fourier analysis, the coordination numbers (N) and the nearest-neighbor distances (R) to As atoms in the first shell were extracted from the XAFS data. When As precipitates as monoclinic SiAs, the nearest-neighbor distances and coordination numbers are ∼2.37 Å and ∼3, as opposed to ∼2.40 Å and ∼4 when As is substitutional. Based on this information, the critical implant dose where the precipitation/clustering of As starts, and the ratio of the substitutional versus cluster/precipitate form As in the samples were determined.

scholarly journals The Formation of Amorphous Silicon by Light Ion Damage

1985 ◽  
Vol 45 ◽  
Author(s):  
Y. Shih ◽  
J. Washburn ◽  
E.R. Weber ◽  
R. Gronsky
Keyword(s):  
Ion Implantation ◽  
Amorphous Silicon ◽  
Point Defect ◽  
Point Defects ◽  
Liquid Nitrogen Temperature ◽  
Paramagnetic Resonance ◽  
High Resolution Tem ◽  
Different Temperatures ◽  
Boron Ions ◽  
Point Defect Clusters

ABSTRACTA model for formation of amorphous silicon by light ion implantation is proposed. It is suggested that accumulation of point defects and/or complexes is required at the initial stage of the amorphization process. Amorphous zones can only form at the end of incoming light ion tracks when the pre-accumulated concentration of point defects reaches a critical value. Depending on the uniformity of the point defect distribution, two possibilities for the second stage of amorphization are suggested when ion implantation is performed at different temperatures.Silicon wafers implanted with boron ions below and above the critical amorphization dose at various temperatures have been investigated using cross section specimens in high resolution TEM. Complementary analyses of these specimens by Electron Paramagnetic Resonance have revealed the presence of dangling bonds in amorphous zones and point defect clusters. Extrinsic stacking faults with 1/3 <111> displacements and other smaller distortions with 1/x<111> displacements were also found to result from the amorphization process. Liquid nitrogen temperature was found to be necessary to cause complete amorphization of silicon by boron ion implantation.

Optimization of Ion Implantation processes for 4H-SiC DIMOSFET

MRS Advances ◽  
2016 ◽  
Vol 1 (55) ◽  
pp. 3673-3678 ◽  
Author(s):  
N. Piluso ◽  
E. Fontana ◽  
M.A. Di Stefano ◽  
G. Litrico ◽  
S. Privitera ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Point Defects ◽  
Electrical Characteristic ◽  
Implantation Dose ◽  
Annealing Process ◽  
Considerable Improvement ◽  
Electrical Characteristics ◽  
Different Temperatures ◽  
Implantation Process

AbstractIn this paper the defects generated by ion implantation in 4H-SiC DIMOSFET (Double Implanted MOSFETs), and their evolution after annealing process, have been studied in detail. The point defects generated by the source or body implantation process have been detected by micro-photoluminescence (µPL) and the effect of these defects on the electrical characteristics of the DIMOSFET has been studied. The role of the annealing process has been carefully investigated by using different temperatures. It appears fundamental for the restoring of the crystal damage. The effect of the ion implantation dose has been investigated as well. By reducing the source ion implanted dose a large decrease of point defects has been detected and a considerable improvement of the electrical characteristic of the DIMOSFET has been observed.

Amorphization of Silicon by Boron Ion Implantation

1986 ◽  
Vol 71 ◽  
Author(s):  
Y. Shih ◽  
J. Washburn ◽  
R. Gronsky ◽  
E.R. Weber
Keyword(s):  
Ion Implantation ◽  
Amorphous Silicon ◽  
Point Defects ◽  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Critical Energy ◽  
High Energy ◽  
Dose Rates ◽  
Initial Stage ◽  
Boron Ions

AbstractAmorphization of silicon due to implantation of boron ions which is the lightest element used for I.C. fabrication processes, has been systematically studied for various temperatures, voltages and dose rates. A model for formation of amorphous silicon by light ion implantation is proposed. It is suggested that accumulation of point defects and/or clusters is required at the initial stage of amorphization process. Diinterstitial -divacancy pairs are suggested to be the embryos of amorphous zones formed during implantation at room temperature. Out -diffusion of highly mobile interstitials during amorphization is thought to explain differences in the critical energy for amorphization with low and high energy implantation at liquid nitrogen temperature.

scholarly journals Quick X-ray reflectivity using monochromatic synchrotron radiation for time-resolved applications

2018 ◽  
Vol 25 (3) ◽  
pp. 706-716 ◽  
Author(s):  
H. Joress ◽  
J. D. Brock ◽  
A. R. Woll
Keyword(s):  
Synchrotron Radiation ◽  
Film Growth ◽  
Sample Surface ◽  
High Energy ◽  
Time Resolved ◽  
Synchrotron Source ◽  
X Ray ◽  
Area Detector ◽  
Monochromatic Synchrotron

A new technique for the parallel collection of X-ray reflectivity (XRR) data, compatible with monochromatic synchrotron radiation and flat substrates, is described and applied to thein situobservation of thin-film growth. The method employs a polycapillary X-ray optic to produce a converging fan of radiation, incident onto a sample surface, and an area detector to simultaneously collect the XRR signal over an angular range matching that of the incident fan. Factors determining the range and instrumental resolution of the technique in reciprocal space, in addition to the signal-to-background ratio, are described in detail. This particular implementation records ∼5° in 2θ and resolves Kiessig fringes from samples with layer thicknesses ranging from 3 to 76 nm. The value of this approach is illustrated by showingin situXRR data obtained with 100 ms time resolution during the growth of epitaxial La0.7Sr0.3MnO3on SrTiO3by pulsed laser deposition at the Cornell High Energy Synchrotron Source (CHESS). Compared with prior methods for parallel XRR data collection, this is the first method that is both sample-independent and compatible with the highly collimated, monochromatic radiation typical of third-generation synchrotron sources. Further, this technique can be readily adapted for use with laboratory-based sources.

Recrystallization Characteristics of Amorphous Si

1988 ◽  
Vol 100 ◽  
Author(s):  
Rodney A. Herring ◽  
Eric M. Fiore
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Single Crystal ◽  
High Energy ◽  
Formation Mechanisms ◽  
Implantation Energy ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Amorphous Si

ABSTRACTThe microstructure of high-energy (0.5–6.0 MEV) As-ion implanted Si and rapid thermal annnealed (RTA'd) Si has been studied by transmission electron microscopy (TEM). The implantations formed buried amorphous layers that recrystallized during RTA at different temperatures and became either single crystal or polycrystalline depending on their implation energy and fluence. At energies > 2.5 MeV and fluences < 1015 cm−2, recrystallization occurred below 400°C and regowth was single crystal. At an energy of 6 MeV and fluence of 5 × 1015 cm−2 recrystallization occurred above 600°C and regrowth was polycrystalline. When the implantation energy and fluence were reduced to 0.5 MeV and 2 × 1014 cm−2, respectively, recrystallization occurred above 600°C and regrowth was polycrystalline. The above results are explained by both the formation mechanisms of amorphous Si resulting from ion implantation and the structural order of a-Si.

Observation of Superlattice Dislocations on Cube Planes in Ni3Al

1973 ◽  
Vol 31 ◽  
pp. 174-175 ◽  
Author(s):  
J. M. Oblak ◽  
W. H. Rand
Keyword(s):  
Nearest Neighbor ◽  
Antiphase Boundary ◽  
Nearest Neighbors ◽  
High Energy ◽  
Cross Slip ◽  
Octahedral Plane ◽  
Trapping Mechanism ◽  
Slip Traces

The energy of an a/2 <110> shear antiphase. boundary in the Ll2 expected to be at a minimum on {100} cube planes because here strue ture is there is no violation of nearest-neighbor order. The latter however does involve the disruption of second nearest neighbors. It has been suggested that cross slip of paired a/2 <110> dislocations from octahedral onto cube planes is an important dislocation trapping mechanism in Ni3Al; furthermore, slip traces consistent with cube slip are observed above 920°K.Due to the high energy of the {111} antiphase boundary (> 200 mJ/m2), paired a/2 <110> dislocations are tightly constricted on the octahedral plane and cannot be individually resolved.

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Application of Lattice Imaging Techniques to Amorphous Films

1975 ◽  
Vol 33 ◽  
pp. 8-9
Author(s):  
S. R. Herd ◽  
P. Chaudhari
Keyword(s):  
Nearest Neighbor ◽  
Random Network ◽  
Imaging Techniques ◽  
Network Models ◽  
Accurate Method ◽  
Direct Transmission ◽  
Lattice Imaging ◽  
Transmission Electron ◽  
Lattice Planes ◽  
Nearest Neighbor Distances

Electron diffraction and direct transmission have been used extensively to study the local atomic arrangement in amorphous solids and in particular Ge. Nearest neighbor distances had been calculated from E.D. profiles and the results have been interpreted in terms of the microcrystalline or the random network models. Direct transmission electron microscopy appears the most direct and accurate method to resolve this issue since the spacial resolution of the better instruments are of the order of 3Å. In particular the tilted beam interference method is used regularly to show fringes corresponding to 1.5 to 3Å lattice planes in crystals as resolution tests.

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

1985 ◽  
Vol 43 ◽  
pp. 154-157
Author(s):  
A.J. Tousimis
Keyword(s):  
Ion Beam ◽  
Depth Resolution ◽  
Sample Surface ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Electrons And Ions ◽  
Spatial Depth ◽  
Minimum Surface Area ◽  
Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

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