MoirÉ Pattern Studies of Thin Layers Deposited on (001)Si Substrates: Cases of Tisi2 and GaAs.

1989 ◽  
Vol 148 ◽  
Author(s):  
A. Rocher ◽  
X. Wallart ◽  
M.N. Charasse
Keyword(s):  
Three Dimensional ◽  
Thin Layers ◽  
Dislocation Network ◽  
Threading Dislocations ◽  
Si Substrates ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Dimensional Growth ◽  
Residual Strains

ABSTRACTMoiré pattern images have been used to investigate the crystalline quality of thin films deposited on (100)Si substrates. Observations performed on TiSi2 show a three-dimensional growth process and two different epitaxial modes. In the case of GaAs epilayers, it is shown that the residual strains are not uniformly distributed in the layer. Residual strain and threading dislocations are related to imperfections of the misfit dislocation network.

Study on the Surface Quality of Al2O3 Nano-Films by Ion Beam Sputtering Deposition

2011 ◽  
Vol 148-149 ◽  
pp. 54-57
Author(s):  
Xiao Ping Lin ◽  
Yun Dong ◽  
Lian Wei Yang
Keyword(s):  
Surface Quality ◽  
Ion Beam ◽  
Three Dimensional ◽  
Ion Beam Sputtering ◽  
Sputtering Deposition ◽  
Atomic Force ◽  
Beam Sputtering ◽  
Dimensional Growth ◽  
Different Thickness

The Al2O3 nano-films of different thicknesses (1~100nm) were successfully deposited on the monocrystalline Si surface by using ion beam sputtering deposition. The surface topography and the component of nano-films with different thickness were analyzed. The quality of the surface of nano-films was systematically studied. When the films’ thickness increase, the studies by atomic force microscope (AFM), X-ray photoelectron spectrum（XPS） show that the gathering grain continually grows up and transits from acerose cellula by two-dimensional growth to globularity by three-dimensional growth. The elements O, Al and Si were found on the surface of Al2O3 nano-films. With the thickness of the films increasing, the content of Al gradually increases and the intensity peak of Si wears off, the surface quality of the deposited films is ceaselessly improved

Measurement of Gingival Swelling from Dental Casts by Generation of a Moire Pattern with Laser Light

1988 ◽  
Vol 67 (8) ◽  
pp. 1118-1121 ◽  
Author(s):  
F.R. Wouters ◽  
C. Jon-And ◽  
N. Abramson ◽  
L. Olsson ◽  
L. Frithiof ◽  
...  
Keyword(s):  
Laser Light ◽  
Three Dimensional ◽  
Processing System ◽  
Measuring Method ◽  
Direct Evaluation ◽  
Moire Pattern ◽  
Moiré Pattern ◽  
Helium Neon Laser ◽  
Computer Based ◽  
Dental Casts

The aim of the study was to develop a sensitive measuring method enabling direct evaluation of gingival swelling to be made as registered on dental casts. On two separate occasions, when different degrees of severity of gingival inflammation were present in the same subject, reversible hydrocolloid impressions were taken of the mandible. The casts obtained were located successively in identical three-dimensional relationships in a field of interference fringes generated by two intersecting beams of collimated helium-neon laser light, and were photographed. The evaluation of the moiré pattern obtained directly by superimposition of the two images of the surface studied indicated that a decrease in gingival height of 0.38 mm in the direction of the camera had occurred between the two occasions. The use of a computer-based image-processing system considerably improved the visibility of the pattern. The reproducibility of the impression technique, as well as the relocation and superimposing techniques, proved satisfactory at the moiré resolution used (0.19 mm). The method has potential application in clinical experimental research, and therefore warrants further evaluation.

Microstructure of thin layers of MBE-grown GaAs on Si substrates

1986 ◽  
Vol 67 ◽  
Author(s):  
S. J. Rosner ◽  
S. M. Koch ◽  
J. S. Harris ◽  
S. Laderman
Keyword(s):  
Structural Evolution ◽  
Normal Growth ◽  
Optical Quality ◽  
Thin Layers ◽  
Buffer Layers ◽  
Initial Growth ◽  
Slow Growth Rate ◽  
Si Substrates ◽  
Ion Channeling

ABSTRACTThe ability to grow high quality epitaxial GaAs films directly on Si substrates has recently been demonstrated by Molecular Beam Epitaxy. Many of the most successful growth techniques include initial growth at low temperatures and slow growth rate to nucleate the compound on the elemental semiconductor with subsequent normal growth under conditions used for homoepitaxial GaAs MBE. The mechanisms for the success of this method are still poorly understood. This work focusses on a study of the structural evolution of this low temperature initial layer and conventionally grown overlayer. Thin films in the 5 to 300 nm range were used to evaluate the effect of the temperature and thickness on the growth process. Thicker films, described elsewhere, were used to evaluate the crystalline and optical quality of potential device layers.The structure of the thin buffer layers was studied as a function of both temperature and thickness. The crystalline quality of these layers was found to be quite poor, with substantial disorder at the GaAs/Si interface. The quality improved slowly as a function of thickness. The effect of the conventional overgrowth on this initil layer was also investigated. It was found that the quality of the low tumperature layer improved as normal overgrowth continued, as measured by ion channeling aligned yields. After 200 nm of overgrowth, ion channeling aligned yields from the material at the interface had declined substantially. This indicates that substantial regrowth and annealing of defects occurs as growth continues. These observations are further confirmed by TEM.

Confinement of Threading Dislocations in Simox with a GeSi Strained Layer

1990 ◽  
Vol 198 ◽  
Author(s):  
F. Namavar ◽  
E. Cortesi ◽  
D.L. Perry ◽  
E.A. Johnson ◽  
N.M. Kalkhoran ◽  
...  
Keyword(s):  
Alloy Layer ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Epitaxial Silicon ◽  
Strained Layers ◽  
Strained Layer ◽  
Si Substrates ◽  
Plane View ◽  
Gesi Layer

ABSTRACTWe have investigated improving the crystalline quality of epitaxial silicon grown on SIMOX by confining threading dislocations in the original Si top layer using a GeSi strained layer. Epitaxial Si/GeSi/Si structures were grown by CVD on SIMOX and Si substrates with a GeSi alloy layer about 1000 − 1500 angstroms thick with Ge concentrations of about 0−20%. A Ge concentration in the alloy layer of about 5.5% or higher appears to be necessary in order to bend any of the threading dislocations from the original SIMOX top layer. For a higher Ge concentration of about 16%, most of the threading dislocations appear to be bent and confined by the GeSi layer. In addition, the GeSi strained layers grown by CVD (at about 1000°C) appear to be high quality and no misfit dislocations were observed in the regions studied by XTEM and plane view TEM.

TEM Investigation of Si/βFeSi2/Si (100) and (111) Heterostructures Formed by Fe Implantation

1992 ◽  
Vol 283 ◽  
Author(s):  
C. W. T. Bulle-Lieuwma ◽  
D. J. Oostra ◽  
D. E. W. Vandenhoudt
Keyword(s):  
Three Dimensional ◽  
Si Substrate ◽  
Structural Examination ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dimensional Growth ◽  
Buried Layer ◽  
High Degree ◽  
Dimensional Surface ◽  
Fe Implantation

ABSTRACTSi/βFeSi2/Si (100) and (111) structures were obtained by implantation of 450 keV Fe+ ions with a dose of 6×1017 Fe+ ions/ cm2 into Si substrates. A continuous buried βFeSi2 layer with thickness of 250 nm was formed during subsequent annealing. By transmission electron microscopy it has been found that for (100) Si the layer consists of βFeSi2 grains with lateral dimensions of approximately O.5 μm and for (111) Si of grains of 5 μm in size. The βFeSi2 films exhibit a high degree of epitaxy with the Si substrate. A detailed structural examination shows the occurrence of several epitaxial relationships of βFeSi2 with the Si substrate. In contrast to two-dimensional surface growth techniques, the formation of a buried layer by implantation occurs by a three-dimensional growth process by the coalescence of βFeSi2 precipitates. The different orientations of the βFeSi2 grains in the buried layer are already established by the orientation of the precipitates formed during implantation.

scholarly journals Analysis of edge threading dislocations b→=12〈110〉 in three dimensional Ge crystals grown on (001)-Si substrates

2015 ◽  
Vol 107 (9) ◽  
pp. 093501 ◽  
Author(s):  
Y. Arroyo Rojas Dasilva ◽  
M. D. Rossell ◽  
D. Keller ◽  
P. Gröning ◽  
F. Isa ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Threading Dislocations ◽  
Si Substrates

The Crystalline Quality of Epitaxial Si Layers Solution Grown on Polycrystalline Si Substrates

1994 ◽  
Vol 358 ◽  
Author(s):  
M. Albrecht ◽  
B. Steiner ◽  
Th. Bergmann ◽  
A. Voigt ◽  
W. Dorsch ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Epitaxial Layer ◽  
Defect Density ◽  
Thin Layers ◽  
Induced Current ◽  
Si Substrates ◽  
Transmission Electron ◽  
Current Transmission ◽  
Electron Beam Induced Current

ABSTRACTWe investigate the crystalline and electrical quality of thin layers epitaxially grown on polycrystalline substrates from metallic solution by the method of electron beam induced current, transmission electron microscopy and etching experiments. We observe a reduced recombination strength of dislocations and small angle grain boundaries, i.e. an improved electrical quality of the epitaxial layer compared to the substrate. The improved quality can be attributed (i) to an altered structure of grain boundaries and dislocations and (ii) to a reduced defect density in the epitaxial layer.

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