Point defect generation during the oxidation of silicon

1978 ◽  
Vol 36 (1) ◽  
pp. 320-321
Author(s):  
J.A. Lambert ◽  
P.S. Dobson
Keyword(s):  
Thin Foil ◽  
Geometrical Factor ◽  
Dislocation Loops ◽  
Self Diffusion ◽  
Self Energy ◽  
Thin Foils ◽  
Perfect Dislocation ◽  
Interstitial Defects ◽  
Boron Ions ◽  
Image Position

The interstitial defects created during ion-implantation in silicon condense out during annealing to form extrinsically faulted Frank loops and perfect dislocation loops. The annealing behaviour of these defects has been investigated by annealing electron microscope thin foils. It was found that the loops shrink and eventually disappear after annealing in the temperature range 900-1020° C in vacuum. Figure 1a shows faulted and perfect loops after implanting with 10 15 boron ions cm-2 at 40kV and bulk annealing for 50 minutes in nitrogen at 950° C. The thin foil was then annealed for 30 minutes at 1000° C in vacuum and figure 1b shows that the loops have shrunk during this treatment.The loop shrinkage is caused by the diffusion of interstitial point defects from the loop to the surface and the driving force for this process is provided by the self energy of the loops. The rate of shrinkage is given bywhere A is a geometrical factor, Ds is the coefficient of self diffusion and ΔF is the change in the free energy of the loop per emitted interstitial.

Effets of surfaces on precipitate morphology in irradiated thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 654-655
Author(s):  
D.I. Potter ◽  
A. Taylor
Keyword(s):  
Ion Irradiation ◽  
Dark Field Image ◽  
Thin Foil ◽  
Dark Field ◽  
Al Alloy ◽  
Bright Field Image ◽  
Dislocation Loops ◽  
Precipitate Morphology ◽  
Thin Foils

Thermal aging of Ni-12.8 at. % A1 and Ni-12.7 at. % Si produces spatially homogeneous dispersions of cuboidal γ'-Ni3Al or Ni3Si precipitate particles arrayed in the Ni solid solution. We have used 3.5-MeV 58Ni+ ion irradiation to examine the effect of irradiation during precipitation on precipitate morphology and distribution. The nearness of free surfaces produced unusual morphologies in foils thinned prior to irradiation. These thin-foil effects will be important during in-situ investigations of precipitation in the HVEM. The thin foil results can be interpreted in terms of observations from bulk irradiations which are described first.Figure 1a is a dark field image of the γ' precipitate 5000 Å beneath the surface(∿1200 Å short of peak damage) of the Ni-Al alloy irradiated in bulk form. The inhomogeneous spatial distribution of γ' results from the presence of voids and dislocation loops which can be seen in the bright field image of the same area, Fig. 1b.

Defects in ion implanted silicon

1978 ◽  
Vol 36 (1) ◽  
pp. 386-387
Author(s):  
J.A. Lambert ◽  
P.S. Dobson
Keyword(s):  
Defect Structure ◽  
Dislocation Loops ◽  
Frank Loop ◽  
Burgers Vector ◽  
Temperature Range ◽  
Perfect Dislocation ◽  
Contrast Analysis ◽  
Image Position ◽  
Ion Implanted

The defect structure of ion-implanted silicon, which has been annealed in the temperature range 800°C-1100°C, consists of extrinsic Frank faulted loops and perfect dislocation loops, together with‘rod like’ defects elongated along <110> directions. Various structures have been suggested for the elongated defects and it was argued that an extrinsically faulted Frank loop could undergo partial shear to yield an intrinsically faulted defect having a Burgers vector of 1/6 <411>.This defect has been observed in boron implanted silicon (1015 B+ cm-2 40KeV) and a detailed contrast analysis has confirmed the proposed structure.

scholarly journals Relative Stability of Silicon Self-Interstitial Defects

2000 ◽  
Vol 610 ◽  
Author(s):  
G. Subramanian ◽  
K.S. Jones ◽  
M.E. Law ◽  
M.J. Caturla ◽  
S. Theiss ◽  
...  
Keyword(s):  
Relative Stability ◽  
Defect Size ◽  
Dislocation Loops ◽  
Transmission Electron ◽  
Perfect Dislocation ◽  
Recent Transmission ◽  
Interstitial Defects ◽  
Annealing Study ◽  
Formation Energies ◽  
Weber Potential

Abstract{311) defects and dislocation loops are formed after ion-implantation and annealing of a silicon wafer. Recent Transmission Electron Microscopy studies by Li and Jones have shown that sub-threshold dislocation loops nucleate from {311} defects. In our study, the conjugate gradient method with the Stillinger Weber potential is used to relax different configurations such as {311} defects with a maximum of five chains and perfect dislocation loops. From the formation energies thus obtained we find that there is an optimal width for each length of the {311} defects. Moreover the relative stability of {311}s and loops is studied as a function of defect size. We observe that at very small sizes the perfect loops are more stable than the {311}s. This may provide an explanation for the experimental observation by Robertson et al that, in an annealing study of end of range damage of amorphized samples, 45% of the loops had nucleated in the first 10 minutes of anneal. Out of these 25% of the loops could not have nucleated by unfaulting of {311}s. We propose that homogeneous nucleation, as against unfaulting of the {311}s, could be the source of these sub-microscopic loops.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

Growth of hematite by surface oxidation of olivine

1988 ◽  
Vol 46 ◽  
pp. 800-801
Author(s):  
S. McKernan ◽  
C. B. Carter
Keyword(s):  
Electron Microscope ◽  
Surface Oxidation ◽  
Thin Foil ◽  
Nucleation And Growth ◽  
Ion Milling ◽  
Annealed Material ◽  
Thin Foils ◽  
Natural Olivine ◽  
Approximate Composition ◽  
Second Phases

The oxidation of natural olivine has previously been performed on bulk samples and the reactions followed by preparation of TEM specimens from the annealed material. These results show that below ∼1000°C hematite and amorphous silica are formed, particularly around dislocations. At higher temperatures magnetite and some enstatite-like phase are formed. In both cases the olivine is left almost totally Fe depleted. By performing the oxidation on characterized thin TEM specimens it is possible to obtain more information on the nucleation and growth of the second phases formed. The conditions in a thin foil, however, are very different from those in the bulk especially with regard to surface effects. The nucleation of precipitates in particular may be expected to occur differently in these thin foils than in the bulk.TEM specimens of natural olivine (approximate composition Mg+Fe+Si2o4) which had been annealed at 1000°C for 1 hr were prepared by mechanical polishing and dimpling, followed by Ar ion milling to perforation. The specimens were characterized in the electron microscope and then heated in air in alumina boats to 900°C for between 30 and 180 minutes.

Influence of ion-milling on the T2 phase in Al-2.5%Li-2.5%Cu alloy

1989 ◽  
Vol 47 ◽  
pp. 288-289
Author(s):  
J. R. Reed ◽  
D. J. Michel ◽  
P. R. Howell
Keyword(s):  
Thin Foil ◽  
Icosahedral Symmetry ◽  
Ion Milling ◽  
Cu Alloy ◽  
Thin Foils ◽  
Heat Treated ◽  
Aluminum Solid Solution ◽  
In Situ Heating ◽  
The Stability

The Al6Li3Cu (T2) phase, which exhibits five-fold or icosahedral symmetry, forms through solid state precipitation in dilute Al-Li-Cu alloys. Recent studies have reported that the T2 phase transforms either during TEM examination of thin foils or following ion-milling of thin foil specimens. Related studies have shown that T2 phase transforms to a microcrystalline array of the TB phase and a dilute aluminum solid solution during in-situ heating in the TEM. The purpose of this paper is to report results from an investigation of the influence of ion-milling on the stability of the T2 phase in dilute Al-Li-Cu alloy.The 3-mm diameter TEM disc specimens were prepared from a specially melted Al-2.5%Li-2.5%Cu alloy produced by conventional procedures. The TEM specimens were solution heat treated 1 h at 550°C and aged 1000 h at 190°C in air to develop the microstructure. The disc specimens were electropolished to achieve electron transparency using a 20:80 (vol. percent) nitric acid: methanol solution at -60°C.

A Study on the Micro Property Testing of Micro Embossing Patterned Metallic Thin Foil

2007 ◽  
Vol 345-346 ◽  
pp. 335-338
Author(s):  
Hye Jin Lee ◽  
Nak Kyu Lee ◽  
Hyoung Wook Lee
Keyword(s):  
Mechanical Properties ◽  
Optimal Design ◽  
Design Procedure ◽  
Thin Foil ◽  
Property Testing ◽  
Rolling Process ◽  
Industrial Technology ◽  
Cold Isostatic Press ◽  
Nano Indentation ◽  
Thin Foils

In this paper, Experimental results on the measurement of mechanical properties of fine patterns in the MEMS structure are described. The mechanical properties of embossing patterns on metallic thin foil is measured using the nano indentation system, that is developed by Korea Institute of Industrial Technology(KITECH). These micro embossing patterns are fabricated using CIP(Cold Isostatic Press) process on micro metallic thin foils(Al-1100) that are made by rolling process. These embossing patterned metallic thin foils(Al-1100) are used in the reflecting plate of BLU(Back Light Unit) and electrical/mechanical MEMS components. If these mechanical properties of fine patterns are utilized in a design procedure, the optimal design can be achieved in aspects of reliability as well as economy.

Effect of Self-Interstitial Diffusion Anisotropy in Electron-Irradiated Zirconium. A Cluster Dynamics Modeling

2005 ◽  
Vol 237-240 ◽  
pp. 659-664
Author(s):  
Frédéric Christien ◽  
Alain Barbu
Keyword(s):  
Point Defects ◽  
Thin Foil ◽  
Elastic Interaction ◽  
Dislocation Loops ◽  
Considerable Influence ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Diffusion Anisotropy ◽  
Vacancy Loops ◽  
Transmission Electron

Irradiation of metals leads to the formation of point-defects (vacancies and selfinterstitials) that usually agglomerate in the form of dislocation loops. Due to the elastic interaction between SIA (self-interstitial atoms) and dislocations, the loops absorb in most cases more SIA than vacancies. That is why the loops observed by transmission electron microscopy are almost always interstitial in nature. Nevertheless, vacancy loops have been observed in zirconium following electron or neutron irradiation (see for example [1]). Some authors proposed that this unexpected behavior could be accounted for by SIA diffusion anisotropy [2]. Following the approach proposed by Woo [2], the cluster dynamics model presented in [3] that describes point defect agglomeration was extended to the case where SIA diffusion is anisotropic. The model was then applied to the loop microstructure evolution of a zirconium thin foil irradiated with electrons in a high-voltage microscope. The main result is that, due to anisotropic SIA diffusion, the crystallographic orientation of the foil has considerable influence on the nature (vacancy or interstitial) of the loops that form during irradiation.

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