Tem Study of Metal Impurity Precipitates in the Surface Regions of Silicon Wafers

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Seibt ◽  
K. Graff
Keyword(s):  
Particle Growth ◽  
High Resolution Electron Microscopy ◽  
Minor Role ◽  
Specimen Preparation ◽  
Dislocation Loops ◽  
Experimental Conditions ◽  
Resolution Electron ◽  
Precipitation Behaviour ◽  
Precipitation Phenomena ◽  
A Minor

ABSTRACTThe precipitation behaviour of the transition metals Co, Ni, Cu and Pd has been studied by means of conventional and high - resolution electron microscopy. Special experimental conditions for specimen preparation were chosen, which lead to the formation of haze. These conditions were the same for all metals. Therefore, a direct comparison of the respective precipitation phenomena was possible. Co and Ni were found to precipitate as Si - rich silicide particles exhibiting various morphologies attributed to different stages of particle growth and ripening. It is shown that the generation of Si- self - interstitials (and vacancies) plays a minor role in the preci-pitate formation. On the other hand Cu and Pd precipitate as metal - rich silicide particles. They form star - like colonies consisting of small particles and extended extrinsic edge - type dislocation loops. The precipitation behaviour of these two met-als is governed by the generation of Si - self - interstitials due to the large misfit of the metal - rich silicide particles.

Precipitation phenomena in non-stoichiometric oxides I. Pairs of crystallographic shear planes in reduced rutiles

1984 ◽  
Vol 391 (1801) ◽  
pp. 351-372 ◽  
Keyword(s):  
High Resolution Electron Microscopy ◽  
Specimen Preparation ◽  
Cooling History ◽  
Chemical Systems ◽  
Interstitial Defect ◽  
Resolution Electron ◽  
Crystallographic Shear ◽  
Precipitation Phenomena ◽  
New Phenomena ◽  
Shear Planes

High-resolution electron microscopy, in conjunction with controlled specimen preparation procedures, has enabled the nature and structure of the small defects existing within the nonstoichiometric phase TiO 2-x (0 ≤ x ≤ 0.01) to be investigated. In particular, the precipitation of pairs of crystallographic shear planes (c. s. p.) and their subsequent separation has been observed. The atomic mechanisms involved in c. s. p. nucleation and growth and the eventual evolution to an ordered c. s. structure have been elucidated by using new linear cationic interstitial defect structural models. The results emphasize the decisive influence that cooling history has on the microstructures observed at room temperature and suggest that similar new phenomena will be discovered in observations of other non-stoichiometric chemical systems.

Precipitation phenomena in non-stoichiometric oxides II. {100} Platelet defects in reduced rutiles

1984 ◽  
Vol 391 (1801) ◽  
pp. 373-391 ◽  
Keyword(s):  
High Resolution Electron Microscopy ◽  
Specimen Preparation ◽  
History Plays ◽  
Chemical Systems ◽  
Topological Features ◽  
Interstitial Defect ◽  
Resolution Electron ◽  
Crystallographic Shear ◽  
Platelet Defects ◽  
Precipitation Phenomena

High-resolution electron microscopy, in conjunction with controlled specimen preparation procedures, has enabled the nature and structure of novel {100} platelet defects found in TiO 2-x (0 < x < 0.0035) to be studied at close to atomic resolution The precipitation of these platelet defects, often occurring in association with crystallographic shear planes (c.s.p.), can be explained in terms of new linear cationic interstitial defect models which must exist within the non-stoichiometric phase TiO 2-x . Moreover, models for the platelet defects and c.s.p.-platelet defect structures have been derived that explain the topological features of the experimental images as well as shedding new light on the atomic mechanisms involved in precipitation of c.s.p. and platelets. The decisive influence that cooling history plays in determining the microstructures observed at room temperature in non-stoichiometric chemical systems is again emphasized. Finally, consideration of the elastic energy associated with torsional strains required to rotate [TiO 6 ] octahedral chains of rutile in the vicinity of the platelet defects and the c.s.p. leads to a qualitative physical explanation for the changeover in precipitation structures from c.s.p. to platelets, dependent on temperature of precipitation (i.e. cooling rate).

Stacking-fault tetrahedra in ion-implanted III-V compounds

1987 ◽  
Vol 45 ◽  
pp. 316-317
Author(s):  
B.C. De Cooman ◽  
S. McKeman ◽  
C.B. Carter
Keyword(s):  
Surface Layer ◽  
Solid Phase ◽  
High Resolution Electron Microscopy ◽  
Stacking Fault ◽  
Dislocation Loops ◽  
Present Contribution ◽  
Stacking Fault Tetrahedra ◽  
Type Layer ◽  
Resolution Electron ◽  
Before And After

The implantation of heavy ions into GaAs for the purpose of obtaining a shallow n-type layer has been studied in detail, The results obtained by Rutherford Backscattering and high-resolution electron microscopy show that the surface layer is amorphized during implantation and that the solid-phase epitactic regrowth gives rise to a surface layer containing a large density of microtwins and stacking faults. No other defects have been reported other than interstitial-type dislocation loops in the implanted material, despite the fact that P-implants in Si had shown that a high density of stacking-fault tetrahedra (SFT) were formed after annealing. The present contribution reviews the major findings obtained during the first observation of SFT in Ga1-xAlxAs/GaAs (x=0.3) superlattices and Ga1-xAlxAs (x=0.3) epilayers grown on (001) GaAs. The material was grown by molecular-beam epitaxy (MBE). The ion energy used was 175kV, the dose was 1015 cm-2 and the Se ions were implanted at room-temperature The specimens were examined before and after a 4 hour anneal at 660°C.

Licvd of Cr(C,O) Films from Cr(CO)6 at 248 NM: Gas-Phase and Surface Processes

1988 ◽  
Vol 129 ◽  
Author(s):  
R. Nowak ◽  
L. Konstantinov ◽  
P. Hess
Keyword(s):  
Carbon Monoxide ◽  
Gas Phase ◽  
Laser Fluence ◽  
Film Deposition ◽  
Surface Processes ◽  
Minor Role ◽  
Relative Importance ◽  
Experimental Conditions ◽  
Krf Excimer Laser ◽  
A Minor

ABSTRACTThe influence of laser fluence and carbon monoxide partial pressure on the deposition rate of thin Cr(C,O) films was investigated. The films were deposited from Cr(CO)6 mixtures with CO and Ar using a KrF excimer laser. The observed results are discussed with respect to the relative importance of gasphase and surface processes. The results reveal that under the present experimental conditions chromium atoms produced in the gas phase play only a minor role as direct film precursors in KrF laser-induced film deposition.

scholarly journals Pathways of glyceride glycerol synthesis

1974 ◽  
Vol 140 (2) ◽  
pp. 249-251 ◽  
Author(s):  
Robert Rognstad ◽  
Dallas G. Clark ◽  
Joseph Katz
Keyword(s):  
Minor Role ◽  
Dihydroxyacetone Phosphate ◽  
Glycerol Phosphate ◽  
Experimental Conditions ◽  
Liver Parenchymal ◽  
Isolated Rat Liver ◽  
Glycerol Synthesis ◽  
A Minor ◽  
Parenchymal Cells ◽  
Intracellular Glycerol

Isolated rat liver parenchymal cells were incubated for various periods with [U-14C,2-3H]glycerol and the radioisotopic yields in the major products were determined, as well as the 3H/14C ratios in glyceride glycerol and intracellular glycerol phosphate. Under the conditions used (0.1mm-glycerol+10mm-l-lactate or 10mm-glycerol as substrates), only small differences were found between these 3H/14C ratios. The results suggest a minor role for a pathway of glyceride glycerol synthesis involving reduction of acylated dihydroxyacetone phosphate, under these experimental conditions.

TEM STUDY OF NEW HIGH-Tc SUPERCONDUCTORS IN THE Bi-Sr-Ca-Cu-O SYSTEM

1988 ◽  
Vol 02 (09) ◽  
pp. 1085-1093 ◽  
Author(s):  
J.Q. LI ◽  
D.Y. YANG ◽  
F.H. LI ◽  
Z.Y. RAN ◽  
Z.X. ZHAO
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Lattice Parameters ◽  
Minor Phase ◽  
High Tc Superconductors ◽  
High Tc ◽  
Superconducting Phases ◽  
Resolution Electron ◽  
A Minor ◽  
Average Structures

Electron diffraction and high resolution electron microscopy have been used to study the structure of superconducting phases in Bi-Sr-Ca-Cu-O system. The average structures of two main superconducting phases Bi 2 Sr 2 CaCu 2 O y and Bi 2 Sr 2 Ca 2 Cu 3 O y have orthorhombic cells with lattice parameters a=5.41Å, b=5.43Å, c=30.7Å and a=5.41Å, b=5.43Å, c=36.8Å respectively. Incommensurate modulations with wave vector nearly along the b* axis appear in both phases. A minor phase in this system with the same lattice parameters a and b but a smaller c(=24.6Å) has also been observed. Intergrowth of lamellae of different phases does occur in Bi-Sr-Ca-Cu-O system.

Carbon Black Morphology: I. Particle Microstructure. II. Automated EM Analysis of Aggregate Size and Shape

1969 ◽  
Vol 42 (4) ◽  
pp. 1209-1234 ◽  
Author(s):  
W. M. Hess ◽  
L. L. Ban ◽  
G. C. McDonald
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Environmental Conditions ◽  
Aggregate Size ◽  
Carbon Black Particle ◽  
Particle Growth ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Black Particle

Abstract Carbon black particle and aggregate microstructure were studied in detail by means of high resolution electron microscopy. Improved instrumental and environmental conditions have enabled more detailed studies on the size, orientation, and spacing of graphite layers in carbon black particles than heretofore possible. The layers form continuous networks about particle growth centers and between adjoining particles and show a paracrystalline orientation rather than individual crystallites. Based on this type of orientation carbon black primary aggregates are now defined as single graphite paracrystals exhibiting either a fibrous (furnace and channel blacks) or spheroidal (thermal blacks) shape.

Transmission electron microscopy in VLSI/ULSI materials and devices: specimen preparation and applications

1987 ◽  
Vol 45 ◽  
pp. 258-259
Author(s):  
H. L. Tsai
Keyword(s):  
Electron Microscopy ◽  
Cross Sections ◽  
Structural Characteristics ◽  
Decisive Role ◽  
High Resolution Electron Microscopy ◽  
Specimen Preparation ◽  
Material Defects ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Device Properties

The performance of a VLSI/ULSI device can be affected by material defects generated during device processing, structural characteristics of the device, and reliability of metallization. In these areas, the transmission electron microscope has been an important tool in helping understand the effects of material defects and process-induced issues on the device properties. With high resolution electron microscopy, it has been possible to characterize the structures of device interfaces, which often play a decisive role in the device performance. Recently, we have applied TEM/HREM to the studies of oxygen precipitation in silicon materials, thermal oxide integrity in VLSI/ULSI devices, and metallization. In order to improve the TEM/HREM capability in VLSI/ULSI devices, a multilayered technique to prepare TEM cross sections has been developed.

scholarly journals The effect of heating on the morphology of crystalline neodymium hydroxycarbonate, NdCO3OH

2014 ◽  
Vol 78 (6) ◽  
pp. 1391-1397 ◽  
Author(s):  
Beatriz Vallina ◽  
Juan Diego Rodriguez-Blanco ◽  
Jesus A. Blanco ◽  
Liane G. Benning
Keyword(s):  
Rapid Heating ◽  
High Resolution Electron Microscopy ◽  
Temperature Treatment ◽  
Slow Heating ◽  
X Ray Diffraction ◽  
Amorphous Precursor ◽  
Experimental Conditions ◽  
Spherulitic Growth ◽  
Resolution Electron ◽  
Increasing Temperature

The crystallization of hexagonal NdCO3OH through hydrothermal synthesis carried out at slow (reaching the desired temperature within 100 min) and quick (50 min) rates of heating but at variable temperatures (165–220ºC) are reported here. The formation of NdCO3OH occurs via the crystallization of an amorphous precursor. Both the precursor and the crystalline NdCO3OH were characterized by X-ray diffraction, infrared spectroscopy and high-resolution electron microscopy. The mechanism of crystallization is very dependent on the experimental conditions (rate of heating and temperature treatment). With increasing temperature, the habit of NdCO3OH crystals changes progressively to more complex spherulitic or dendritic morphologies. The development of these crystal morphologies is suggested here to be controlled by the level at which supersaturation was reached in the aqueous solution during the breakdown of the amorphous precursor. At the highest temperature (220ºC) and during rapid heating (50 min) the amorphous precursor breaks down rapidly and the fast supersaturation promotes spherulitic growth. At the lowest temperature (165ºC) and slow heating (100 min), however, the supersaturation levels are approached more slowly than required for spherulitic growth, and thus more regular, previously unseen, triangular pyramidal shapes form.

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