TEM study of buried yttrium silicide formed by ion implantation

1990 ◽  
Vol 48 (4) ◽  
pp. 570-571
Author(s):  
T.L. Alford ◽  
N.D. Theodore ◽  
J.C. Barbour ◽  
C.B. Carter ◽  
J.W. Mayer
Keyword(s):  
Ion Implantation ◽  
Large Scale ◽  
Schottky Barrier Height ◽  
Lattice Mismatch ◽  
Good Thermal Stability ◽  
Si Substrates ◽  
Transmission Electron ◽  
Metal Silicides ◽  
Vacuum Anneal ◽  
Buried Layers

Metal silicides are now used extensively in very-large-scale-integrated (VLSI) electronics due to their low resistivity, good thermal stability, and ability to form on Si. Of these silicides, yttrium silicide, YSi2-x has essentially 0% lattice mismatch with (111)Si, a low Schottky barrier height on n-type Si, and a unit cell based on the AlB2-type structure, but with 15-20% vacancies on the Si sublattice. Recent investigations of high-temperature ion implantation of yttrium ions into Si have emphasized the formation of buried-silicide layers. This study is focussed on the microstructure and defects in the vicinity of buried YSi2-x layers formed by Y-ion implantation into Si.Yttrium-silicide buried layers were formed by implanting 330 or 660 keV Y ions into (11l)Si substrates held at 450°C followed by a 1000°C, 1-hour vacuum anneal. The implant fluences varied from 1 to 3.6×l017 Y/cm2. Cross-section transmission electron microscopy (XTEM) analysis was carried out using a JEOL 4000EX electron microscope operating at 400 kV.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Dissociation of Misfit Dislocations in GeSi/{111}Si Interfaces

1993 ◽  
Vol 319 ◽  
Author(s):  
Frank Ernst
Keyword(s):  
Lattice Mismatch ◽  
Stacking Faults ◽  
Chemical Vapor ◽  
Interfacial Area ◽  
Dark Field ◽  
Dislocation Network ◽  
Misfit Dislocations ◽  
Si Substrates ◽  
Weak Beam ◽  
Transmission Electron

AbstractThe accommodation of lattice mismatch is studied in Ge0.15Si0.85 layers grown epitaxially on {111}-oriented Si substrates by chemical vapor deposition (CVD) at 1100°C. Weak beam dark field microscopy reveals a regular misfit dislocation network, which resembles the honeycomb network of edge-type dislocations anticipated by the O-lattice theory. In contrast to the latter, however, the real network exhibits extended nodes where the misfit dislocations dissociate into misfit partial dislocations. Between the partials, high resolution transmission electron microscopy (HRTEM) reveals intrinsic and extrinsic stacking faults. Owing to the presence of these stacking faults, three different atomistic structures of the GeSi/Si interface coexist and compete for the interfacial area according to their energy. The observed configuration is shown to minimize the total energy of the interface.

Ultra-shallow Junction Formation via GeB- ion Implantation of Si

2000 ◽  
Vol 610 ◽  
Author(s):  
Xinming Lu ◽  
Lin Shao ◽  
Jianyue Jin ◽  
Qinmian Li ◽  
I. Rusakova ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Annealed Sample ◽  
Ion Source ◽  
Negative Ion ◽  
Cluster Ions ◽  
Junction Depth ◽  
Si Substrates ◽  
Transmission Electron ◽  
One Step ◽  
The One

AbstractGeB− Cluster ions have been used to effectively produce 0.65-2keV boron for low energy ion implantation. We have generated the GeB− cluster ions using the SNICS ion source (source of negative ion by cesium sputtering). Shallow junctions have been made by the GeB− cluster ions implanting into Si substrates at 15keV, 1×1015/cm2 and 5keV, 5×1014/cm2. The junction depth as small as 37nm has been achieved by rapid thermal annealing of the 5 keV sample at 1000°C for 1 second. A two-step annealing was also performed to study the diffusion of B in the GeB− ion cluster implanted Si by annealing the 15 keV implanted sample at 550°C/300sec+1000°C/10sec. We found that the junction depth of the two-step annealed sample was only half of the one-step annealed sample. TEM (transmission electron microscopy) showed clear recrystallization of the amorphized layer with no observable residual defects. We briefly discussed the role of Ge in regards to reduction of the junction depth.

Surface Morphology of SiGe Epitaxial Layers Grown on Uniquely Oriented Si Substrates

2000 ◽  
Vol 648 ◽  
Author(s):  
Morgan E. Ware ◽  
Robert J. Nemanich
Keyword(s):  
Surface Morphology ◽  
Lattice Mismatch ◽  
Morphological Structure ◽  
Epitaxial Layers ◽  
Misfit Dislocations ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Relationship Of

AbstractThe 4% lattice mismatch between Si and Ge creates strain in epitaxial layers of SiGe alloys on Si, and this strain can manifest itself in the morphological structure of the surface of the epitaxial layer. This study explores the relationship of the evolution of the surface morphology of SiGe layers grown on a range of Si surface orientations. We have grown thin, strained and thick, relaxed layers of Si0.7Ge0.3 by solid source molecular beam epitaxy on substrates with surface normals rotated from [001] towards [111] by angles of θ = (0, 2, 4, 10, 22) degrees. The surface morphology was investigated by atomic force microscopy, which showed considerable ordering of surface features on relaxed samples. These features evolve from hut-like structures at 0 degrees to large mesa-like structures separated by pits and crevices at 22 degrees. The organization of these features is also shown to vary with the substrate orientation. Each surface has characteristic directions along which features are aligned, and these directions vary continuously with the angle of rotation of the substrate. Transmission electron microscopy confirmed that misfit dislocations had formed along those same directions. The state of relaxation of each layer is quantified by Raman spectroscopy in order to make a direct correlation between residual strain and surface morphology.

Interfacial Structure and Evolution in Mesotaxial CoSi2/Si Heterostructure

1991 ◽  
Vol 238 ◽  
Author(s):  
S. R. Hull ◽  
Y. F. Hsieh ◽  
A. E. White ◽  
K. T. Short
Keyword(s):  
High Temperature ◽  
Ion Implantation ◽  
Interfacial Structure ◽  
High Temperature Annealing ◽  
Ripening Process ◽  
Si Substrates ◽  
Buried Layers ◽  
Precipitate Nucleation ◽  
And Control ◽  
First Time

ABSTRACTWe describe the evolution and microstructure of Si/CoSi2/Si (100) and (111) heterostructures formed by Co+ ion implantation into Si substrates (“mesotaxy”), followed by high temperature annealing. It is shown that the CoSi2 precipitate nucleation and ripening process, and eventual coalescence into buried layers, is controlled by interfacial structure and energetics. Understanding and control of these processes allows for the first time synthesis of otherwise almost identical CoSi2 buried layers with either twinned or untwinned CoSi2/Si(111) interfaces.

Lateral Solid Phase Epitaxy of Evaporated Amorphous Si Films onto SiO2 Patterns

1983 ◽  
Vol 25 ◽  
Author(s):  
H. Yamamoto ◽  
H. Ishiwara ◽  
S. Furukawa ◽  
M. Tamura ◽  
T. Tokuyama
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Implantation ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Si Substrates ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Si Films ◽  
Kinetics Of

ABSTRACTLateral solid phase epitaxy (L-SPE) of amorphous Si (a-Si) films vacuum-evaporated on Si substrates with SiO2 patterns has been investigated, in which the film first grows vertically in the regions directly contacted to the Si substrates and then grows laterally onto SiO2 patterns. It has been found from transmission electron microscopy and Nomarski optical microscopy that use of dense a-Si films, which are formed by evaporation on heated substrates and subsequent amorphization by Si+ ion implantation, is essentially important for L-SPE. The maximum L-SPE length of 5–6μm was obtained along the <010> direction after 10hourannealing at 600°C. The kinetics of the L-SPE growth has also been investigated.

Transmission electron microscopy characterization of In1−xGaxSb on (001) GaAs heteroepitaxial system

1992 ◽  
Vol 70 (10-11) ◽  
pp. 866-874 ◽  
Author(s):  
M. D. Robertson ◽  
J. M. Corbett ◽  
J. B. Webb ◽  
R. Rousina
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Large Scale ◽  
Lattice Mismatch ◽  
Contrast Imaging ◽  
Cross Sectional ◽  
Diffraction Contrast ◽  
Transmission Electron ◽  
Resolution Electron

Seven In1−xGaxSb [Formula: see text] films grown on a (001) GaAs substrate by metalorganic magnetron sputtering were characterized using cross-sectional transmission electron microscopy techniques. Analysis included high-resolution and diffraction contrast imaging, selected area diffraction, and energy dispersive X-ray methods. The epilayers were not observed to possess significant amounts of large-scale residual strain owing to the lattice mismatch; however, localized strain was apparent under diffraction contrast imaging in some films. High-resolution electron microscope analysis indicated that the interfacial lattice mismatch was accommodated by arrays of 60 and (or) 90° dislocations, the distributions of which were found to obey the Frank–Bilby equation for epitaxial systems. Epilayer tilting was observed in the heteroepitaxial systems that possessed a significant substrate inclination. The magnitude and direction of the film tilt, to a first approximation, appeared to be associated with the particular distribution of 60° dislocations observed at the interface. Also, it was observed that surface roughness of the substrate can lead to grain boundaries in the films. Finally, growth defects, specifically stacking faults and threading dislocations, were present in qualitatively varying degrees in the films studied.

SYNTHESES OF NANOSTRUCTURE BUNDLES BASED ON SEMICONDUCTING METAL SILICIDES

2013 ◽  
Vol 06 (05) ◽  
pp. 1340011 ◽  
Author(s):  
WEN LI ◽  
DAISUKE ISHIKAWA ◽  
HIROKAZU TATSUOKA
Keyword(s):  
Nanostructured Materials ◽  
Template Synthesis ◽  
Large Scale ◽  
Low Cost ◽  
Nanowire Array ◽  
Si Nanowire ◽  
Si Substrates ◽  
Metal Silicides ◽  
Si Nanowire Array ◽  
Direct Growth

A variety of nanostructure bundles and arrays based on semiconducting metal silicides have been synthesized using abundant and non-toxic starting materials. Three types of fabrication techniques of the nanostructure bundles or arrays, including direct growth, template synthesis using natural nanostructured materials and template synthesis using artificially fabricated nanostructured materials are demonstrated. CrSi 2 nanowire bundles were directly grown by the exposure of Si substrates to CrCl 2 vapor at atmospheric pressure. A hexagonal MoSi 2 nanosheet, Mg 2 Si / MgO composite nanowire and Mg 2 Si nanowire bundles and MnSi 1.7 nanowire array were synthesized using a MoS 2 layered material, a SiO x nanofiber bundle, a Si nanowire array, and a Si nanowire array as the templates, respectively. Additionally, the fabrication phenomenon and structural properties of the nanostructured semiconducting metal silicides were investigated. These reactions provided the low-cost and controllable synthetic techniques to synthesize large scale and one-dimensional semiconducting metal silicides for thermoelectric applications.

Transmission Electron Microscopy studies of the vacancy ordering in YSI2-X thin films

1991 ◽  
Vol 49 ◽  
pp. 562-563
Author(s):  
F.-R. Chen ◽  
T. L. Lee ◽  
L. J. Chen
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thin Films ◽  
Diffraction Pattern ◽  
Annealing Temperature ◽  
Lattice Mismatch ◽  
Si Substrate ◽  
Metal Thin Films ◽  
Transmission Electron ◽  
Vacancy Ordering

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

Electron Energy Analysis of Germanium and Silica Layers on Silicon Substrates

1975 ◽  
Vol 33 ◽  
pp. 96-97
Author(s):  
R. W. Ditchfield ◽  
A. G. Cullis
Keyword(s):  
Epitaxial Growth ◽  
Electron Energy ◽  
Silicon Substrates ◽  
Secondary Phases ◽  
Si Substrates ◽  
Transmission Electron ◽  
Layer Structures ◽  
Si Films ◽  
Electron Energy Loss ◽  
Growth Centres

An energy analyzing transmission electron microscope of the Möllenstedt type was used to measure the electron energy loss spectra given by various layer structures to a spatial resolution of 100Å. The technique is an important, method of microanalysis and has been used to identify secondary phases in alloys and impurity particles incorporated into epitaxial Si films.Layers Formed by the Epitaxial Growth of Ge on Si Substrates Following studies of the epitaxial growth of Ge on (111) Si substrates by vacuum evaporation, it was important to investigate the possible mixing of these two elements in the grown layers. These layers consisted of separate growth centres which were often triangular and oriented in the same sense, as shown in Fig. 1.

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