Hgl−xCdxTe Near Surface Characterization using Computer Aided Rutherford Backscattering Spectrometry

1986 ◽  
Vol 90 ◽  
Author(s):  
T.-M. Kao ◽  
T. W. Sigmon
Keyword(s):  
Surface Characterization ◽  
Rutherford Backscattering Spectrometry ◽  
Grazing Angle ◽  
Surface Region ◽  
Rutherford Backscattering ◽  
Structural Defects ◽  
Near Surface ◽  
Lattice Disorder ◽  
Defect Densities ◽  
Distributed Dislocations

ABSTRACTIn this work, we report the use of Rutherford backscattering(RBS) measurements and computer simulations to provide accurate stoichiometry information and semi-quantitative defect densities for the near surface region of Hg1−xCdxTe (MCT). The accuracy of the Hg1−xCdx Te x-values determined by our method is found to be comparable to other commonly used methods, such as FTIR or the electron microprobe. The data obtained as structural defects from RBS channeling measurements are in basic agreement with other techniques, such as chemical etching. The sensitivity of the channeling measurement to uniformly distributed dislocations is found to be about 107−108 cm−2, however, for dislocations forming subgrains, the detectable level of dislocation comes to 105 – 106 cm−2. The depth profiles of lattice disorder resulting from ion implantation into MCT are also extracted from RBS channeling measurements using these simulation programs. These profiles are found to closely match the calculated profiles for the displaced atoms calculated using an implantation modeling program (TRIM). We also report on the use of channeling-in-grazing-angle-out technique for evaluating the stoichiometry of the first few monolayers of the MCT surface.

Optimizing the Depth Resolution of Rutherford Backscattering Through Modeling of Noise Sources

1986 ◽  
Vol 69 ◽  
Author(s):  
John R. Abelson ◽  
T. W. Sigmon
Keyword(s):  
Rutherford Backscattering Spectrometry ◽  
Grazing Angle ◽  
Depth Resolution ◽  
Normal Incidence ◽  
Low Noise ◽  
Forward Scattering ◽  
Rutherford Backscattering ◽  
Acceptance Angle ◽  
Noise Sources ◽  
Near Surface

AbstractGrazing angle configurations improve the depth resolution of Rutherford Backscattering Spectrometry (RBS) because the path length of scattered particles is geometrically increased. But in the limit of very grazing angles the resolution degrades due to the finite detector acceptance angle and low angle forward scattering of the beam, considerations which are not present in near-normal incidence geometries. The forward scattering, for example, worsens the depth resolution approximately as the square of the depth, rather than the familiar square root dependence of energy straggling. We present a simple computational scheme which predicts the depth resolution in any target as a function of scattering depth, beam energy, and the grazing angle. The calculations are simpler than previous studies because we use analytic expressions in place of numerical inputs without loss of accuracy. The results lead directly to an optimum depth resolution. We find good agreement between the predicted resolution and measurements on thin silicon dioxide and amorphous silicon films. Finally, we calculate the resolution expected with the use of ion beams heavier than He+, and find improved near surface depth resolution if a low noise detector is used.

scholarly journals The getters in silicon

2019 ◽  
Vol 21 (1) ◽  
pp. 5-17
Author(s):  
V. A. Kharchenko
Keyword(s):  
Integrated Circuits ◽  
Gas Phase ◽  
Silicon Wafer ◽  
Elevated Temperatures ◽  
Plate Thickness ◽  
Surface Region ◽  
Sample Volume ◽  
Structural Defects ◽  
Oxygen Impurity ◽  
Near Surface

The processes of gettering of fast-diffusing metal impurities and structure defects in silicon, mainly used in the production of integrated circuits, power high-voltage devices, nuclear-doped silicon, are considered. The getters based on structural defects and gas-phase getters based on chlorine-containing compounds are analyzed. It is noted that for the formation of getters on the basis of structural defects, it is necessary to create internal sources for generation of dislocations and formation of precipitate — dislocation clusters. It is shown that dislocations are generated in the mouths of microfractures, which then form a sedentary dislocation grid on the non-working side of the plates. In the second case, defects are created in the area of the plate adjacent to the active layer of the electronic component. The process of creating an internal getter is based on the decomposition of a supersaturated solid oxygen solution in silicon, due to which a complex defect medium consisting of various precipitate-dislocation clusters is formed in the crystal. The packing defect as oxide precipitate with a cloud of Frank’s loops is formed. Two variants of creating an internal getter are considered — first is associated with the distillation of an oxygen impurity from the near-surface region of the plate, the second is associated with a fine adjustment of the distribution of vacancies along the plate thickness. The analysis of the influence of the getter as the defect structure reducing the magnitude of mechanical stress of the beginning of the generation of dislocations, which ultimately can determine the mechanical strength of the silicon wafer.This paper also considers the mechanism of gas-phase medium impurities and defects gettering with the addition of chlorine-containing compounds. It is shown that at elevated temperatures, due to the interaction of silicon atoms with chlorine in the near-surface region of the plate, it is possible to create vacancies that penetrate the sample volume with some probability. As a result, the case DСv > 0, DCi £ 0 is realized, that leads to a change in the composition of microdefects and their density. The examples of practical application of heat treatment in chlorine-containing atmosphere silicon wafer during application of the oxide film, in the case of the target the need for dissolution of the microdefects and of the withdrawal of fast diffusing impurities from the crystal volume, and to prevent the formation of generation-recombination centers in the manufacturing process of devices and in a nuclear doping silicon.

Properties of Gallium Disorder and Gold Implants in GaN

2000 ◽  
Vol 647 ◽  
Author(s):  
W. Jiang ◽  
W.J. Weber ◽  
S. Thevuthasan ◽  
V. Shutthanandan
Keyword(s):  
Rutherford Backscattering Spectrometry ◽  
High Mobility ◽  
Surface Region ◽  
Intermediate Stage ◽  
Near Surface ◽  
Projected Range ◽  
Implantation Damage ◽  
The Mean ◽  
Fluence Range

AbstractEpitaxial single-crystal GaN films on sapphire were implanted 60° off the <0001> surface normal with 1 MeV Au2+ or 3 MeV Au3+ over a fluence range from 0.88 to 86.2 ions/nm2 at 180 and 300 K. The implantation damage was studied in-situ using 2 MeV He+ Rutherford backscattering spectrometry in channeling geometry (RBS/C). The disordering rate in the near- surface region is faster than at the damage peak. In all cases, results show an intermediate stage of Ga disorder saturation at the damage peak. During the thermal annealing at 870 K for 20 min, some Au implants in GaN diffuse into the amorphized surface region, while the remaining Au atoms distribute around the mean ion-projected-range. These results suggest a high mobility of both Ga defects and Au implants in GaN. Deeper damage implantation by 3 MeV Au3+ indicates that GaN cannot be completely amorphized up to the highest ion fluence (86.2 ions/nm2) applied at 300 K.

scholarly journals Acetic Acid Etching of Mg-xGd Alloys

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 117 ◽  
Author(s):  
Marcjanna Maria Gawlik ◽  
Björn Wiese ◽  
Alexander Welle ◽  
Jorge González ◽  
Valérie Desharnais ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Surface Morphology ◽  
Surface Characterization ◽  
Secondary Ion Mass Spectrometry ◽  
Surface Region ◽  
Mass Spectrometry Analysis ◽  
Material Degradation ◽  
Near Surface ◽  
Spectrometry Analysis ◽  
Chemical Surface

Mg-xGd alloys show potential to be used for degradable implants. As rare earth containing alloys, they are also of special interest for wrought products. All applications from medical to engineering uses require a low and controlled degradation or corrosion rate without pitting. Impurities from fabrication or machining, like Fe inclusions, encourage pitting, which inhibits uniform material degradation. This work investigates a suitable etching method to remove surface contamination and to understand the influence of etching on surface morphology. Acetic acid (HAc) etching as chemical surface treatment has been used to remove contamination from the surface. Extruded Mg-xGd (x = 2, 5 and 10) discs were etched with 250 g/L HAc solution in a volume of 5 mL or 10 mL for different times. The microstructure in the near surface region was characterized. Surface characterization was done by SEM, EDS, interferometry, and ToF-SIMS (time-of-flight secondary ion mass spectrometry) analysis. Different etching kinetics were observed due to microstructure and the volume of etching solution. Gd rich particles and higher etching temperatures due to smaller etchant volumes promote the formation of pits. Removal of 2–9 µm of material from the surface was sufficient to remove surface Fe contamination and to result in a plain surface morphology.

Utilization of Charged Particle Backscattering to Study the Near Surface Region of Glasses. Application to Depth Profiling of Lanthanium, Cerium, Thorium and Uranium Induced by Aqueous Leaching.

1981 ◽  
Vol 11 ◽  
Author(s):  
Patrick Trocellier ◽  
Bernard Nens ◽  
Charles Engelmann
Keyword(s):  
Charged Particle ◽  
Depth Profiling ◽  
Surface Region ◽  
Rutherford Backscattering ◽  
Heavy Elements ◽  
Chemical Information ◽  
Concentration Profiles ◽  
Near Surface ◽  
Particle Backscattering

The Rutherford backscattering technique is useful for the determination of the concentration profiles of some heavy elements in the near surface region of glasses, but is not able to provide chemical information on the elements detected.

Ion Beam Induced Modifications of Biocompatible Polymer

2015 ◽  
Vol 239 ◽  
pp. 149-160
Author(s):  
A.M. Abdul-Kader ◽  
Andrzej Turos
Keyword(s):  
Friction Coefficient ◽  
Surface Properties ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Chemical Properties ◽  
Surface Region ◽  
Ion Bombardment ◽  
Hydrogen Release ◽  
Nuclear Reaction Analysis ◽  
Near Surface

Ion beam bombardment has shown great potential for improving the surface properties of polymers. In this paper, the ion beam-polymer interaction mechanisms are briefly discussed. The main objective of this research was to study the effects of H-ion beam on physico-chemical properties of Ultra-high-molecular-weight polyethylene (UHMWPE) as it is frequently used in biomedical applications. UHMWPE was bombarded with 65 keV H-ions to fluences ranging from 1x1014–2x1016 ions/cm2. Changes of surface layer composition produced by ion bombardment of UHMWPE samples were studied. The hydrogen release and oxygen uptake induced by ion beam bombardment were determined by Nuclear reaction analysis (NRA) using the 1H(15N, αγ)12C and Rutherford backscattering spectrometry (RBS), respectively. Tribological and hardness properties at the polymer near surface region were studied by means of friction coefficient and micro-hardness testers, respectively. Wettability of the bombarded surfaces was determined by measuring the contact angle for distilled water. The obtained results showed that the ion bombardment induced hydrogen release increases with the increasing ion fluence. An important effect observed, was the rapid oxidation of samples, which occurs after exposure of bombarded samples to air. These effects resulted in important modifications of the surface properties of bombarded material such as change of friction coefficient, hardness and improved wettability.

Antibacterial effect of silver nanofilm modified stainless steel surface

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540013 ◽  
Author(s):  
F. Fang ◽  
J. Kennedy ◽  
M. Dhillon ◽  
S. Flint
Keyword(s):  
Stainless Steel ◽  
Ion Implantation ◽  
Rutherford Backscattering Spectrometry ◽  
Streptococcus Thermophilus ◽  
Surface Region ◽  
Bacterial Attachment ◽  
Stainless Steel Surface ◽  
Near Surface ◽  
Steel Surfaces ◽  
Biofilm Development

Bacteria can attach to stainless steel surfaces, resulting in the colonization of the surface known as biofilms. The release of bacteria from biofilms can cause contamination of food such as dairy products in manufacturing plants. This study aimed to modify stainless steel surfaces with silver nanofilms and to examine the antibacterial effectiveness of the modified surface. Ion implantation was applied to produce silver nanofilms on stainless steel surfaces. 35 keV Ag ions were implanted with various fluences of 1 × 1015 to 1 × 1017 ions•cm-2 at room temperature. Representative atomic force microscopy characterizations of the modified stainless steel are presented. Rutherford backscattering spectrometry spectra revealed the implanted atoms were located in the near-surface region. Both unmodified and modified stainless steel coupons were then exposed to two types of bacteria, Pseudomonas fluorescens and Streptococcus thermophilus, to determine the effect of the surface modification on bacterial attachment and biofilm development. The silver modified coupon surface fluoresced red over most of the surface area implying that most bacteria on coupon surface were dead. This study indicates that the silver nanofilm fabricated by the ion implantation method is a promising way of reducing the attachment of bacteria and delay biofilm formation.

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