Role of the Surface Steps on the Growth of CrSi2 on {111} Silicon.

1995 ◽  
Vol 402 ◽  
Author(s):  
André M. Rocher ◽  
André Oustry ◽  
Marie José David ◽  
Michel Caumont
Keyword(s):  
Elastic Energy ◽  
Solid Phase ◽  
Misfit Dislocations ◽  
Solid Phase Epitaxy ◽  
Step Width ◽  
Orientation Relationships ◽  
Edge Type ◽  
Burgers Vector ◽  
Surface Steps

AbstractCrSi2 layers grown by solid phase epitaxy on a nominal (111) Si surface exhibit in the same proportion two different orientation relationships, named A and B. When CrSi2 is deposited on a 8° vicinal (111) Si surface, B-type orientation is favoured with respect to the A type. This result can be explained by the fact that both the step width introduced by the miscut and the planar coincidence between {1100}Crsi2 and {111}Si are nearly equal to 23Å. Edge type misfit dislocations are observed at the interface with the same spacing. Their Burgers vector component along [111] is almost compensated by the atomic steps along the <110> directions. The role of the steps is discussed in term of elastic energy. Steps introduce misfit dislocations which make possible coherent growth of the B type orientation.

Strain Relaxation in GaN/AlN Films Grown on Vicinal and On-Axis SiC Substrates

2006 ◽  
Vol 527-529 ◽  
pp. 1513-1516
Author(s):  
J. Bai ◽  
X. Huang ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
B. Wagner ◽  
...  
Keyword(s):  
High Resolution ◽  
Lattice Mismatch ◽  
Strain Relaxation ◽  
Crystalline Quality ◽  
Misfit Dislocations ◽  
Vicinal Surface ◽  
Burgers Vector ◽  
Surface Steps ◽  
Transmission Electron ◽  
Initial Stage

Strain relaxation in the GaN/AlN/6H-SiC epitaxial system grown by vicinal surface epitaxy (VSE) is investigated and compared with that in on-axis epitaxy. High resolution x-ray diffraction (HRXRD) measurements show that GaN films grown by VSE have improved crystalline quality. High resolution transmission electron microscope (HRTEM) studies reveal that there are two types of misfit dislocations (MDs) at AlN/6H-SiC interfaces: 60˚ complete dislocations along <1120 > directions with Burgers vector 1/3<1120 > and 60˚ Shockley partials along <10 10 > directions with Burgers vector 1/3<10 10 >. The latter are usually geometrical partial misfit dislocations (GPMDs) that are dominant in VSE to accommodate the lattice mismatch and stacking sequence mismatch simultaneously. In VSE, it is the high-density GPMDs formed at the vicinal surface steps that facilitate rapid strain relaxation at the initial stage of deposition and hence lead to superior crystalline quality of the subsequently grown GaN films.

Nucleation and Growth of Cosi2 on (001) and (111) Si

1987 ◽  
Vol 102 ◽  
Author(s):  
C.W.T. Bulle-Lieuwma ◽  
A.H. Van Ommen ◽  
J. Hornstra
Keyword(s):  
Electron Microscopy ◽  
Defect Structure ◽  
Nucleation And Growth ◽  
Thermal Reaction ◽  
Nucleation Mechanism ◽  
Misfit Dislocations ◽  
Lattice Match ◽  
Edge Type ◽  
Burgers Vector ◽  
Transmission Electron

ABSTRACTNucleation and growth of epitaxial CoSi2 on Si by the thermal reaction of vapour deposited Co on (001) and (111) Si have been studied by transmission electron microscopy (TEM). On (001)-Si the layer consists of CoSi2 grains. Apart from an aligned (a)-orientation, CoSi2 occurs in a number of orientations, including a (110) preferential (b)-orientation. On (111) Si, single-crystalline layers are obtained, predominantly in the B-type orientation, which is rotated through 180° relative to the aligned (111)-orientation (A-type). The interfacial defect structure consists of misfit dislocations of edge-type with Burgers vector b=a/6<112>, running in <110> directions. The observations for both (001) and (111) Si are related to geometrical lattice match between CoSi2 and Si. In addition to the experimental results, a computer program has been made which calculates the matching between various orientations of CoSi2 and Si. The nucleation of B-type CoSi2 for (111) Si and the different oriented grains for (001) Si are discussed in terms of a nucleation mechanism at steps at the interface in combination with a relatively large mismatch.

Dynamic Annealing Phenomena and the Origin of RTA-Induced “Hairpin” Dislocations

1984 ◽  
Vol 35 ◽  
Author(s):  
W. Maszara ◽  
D.K. Sadana ◽  
G.A. Rozgonyi ◽  
T. Sands ◽  
J. Washburn ◽  
...  
Keyword(s):  
Solid Phase ◽  
Growth Front ◽  
Solid Phase Epitaxy ◽  
Pipe Diffusion ◽  
Burgers Vector ◽  
Low Temperature Annealing ◽  
Nucleation Sites ◽  
Perfect Dislocation ◽  
And Diffusion ◽  
Post Implantation

ABSTRACTThe geometry, origin, and diffusion along hairpin defects in Si were investigated using TEM and SIMS techniques. The defect that grows from the amorphous-crystalline (a/c) interface following solid phase epitaxy growth front was found to be a perfect dislocation with a/2(101) Burgers vector. Misoriented microcrystallites within the a/c transition region are proposed to be nucleation sites for the hairpin dislocations. The density of the crystallites increases with an overall coarsening of the interface which occurs during dynamic annealing processes stimulated by implantation or post-implantation low temperature annealing. Hairpin dislocations were found to pipe-diffuse boron at much higher rates than bulk processes significantly shifting dopant profiles. The diffusion coefficient of boron pipe diffusion at 1150°C was found to be about 104 times higher than the bulk one.

Electron Microscopy Investigation of the Role of Surface Steps in the Generation of Dislocations during MOCVD Growth of GaN on 4H-SiC

2006 ◽  
Vol 527-529 ◽  
pp. 1509-1512 ◽  
Author(s):  
N.D. Bassim ◽  
Mark E. Twigg ◽  
Michael A. Mastro ◽  
Philip G. Neudeck ◽  
Charles R. Eddy ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Substrate Surface ◽  
Atomic Scale ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Nucleation Layer ◽  
Plan View ◽  
Surface Steps

Through the use of specially-prepared on-axis SiC substrates with patterned mesa tops completely free of atomic-scale surface steps, we have previously reported the growth of highquality GaN heteroepitaxial films with greatly reduced threading dislocation densities on the order of 107/cm2. In these films, we reported a defect substructure in which lateral a-type dislocations are present in the nucleation layer but do not bow into threading dislocations during the subsequent GaN growth. This study focuses further on the role of SiC substrate surface steps in the generation of misfit, a-type, and threading dislocations at the heteroepitaxial interface. By using weak-beam imaging (both to eliminate Moiré effects and to observe narrow dislocation images) from plan-view transmission electron microscopy (TEM), we identify dislocations generated on stepped and unstepped mesas and compare their geometries. We observe that misfit dislocations nucleated on an unstepped SiC mesa are confined to one set of a-type Burgers vectors of the form g=1/3 [2110] _ _ , straight and well-ordered so that they are less likely to interact with each other. On the other hand, misfit dislocation structures on a stepped SiC mesa surface are not nearly as well-ordered, having bowed structure with threading dislocations that appear to nucleate at SiC surface steps.

Solid-Phase Epitaxy - Role of Point Defects in Amorphous Solids

1993 ◽  
Vol 319 ◽  
Author(s):  
T.K. Chaki
Keyword(s):  
Epitaxial Growth ◽  
Point Defects ◽  
Solid Phase ◽  
Ion Irradiation ◽  
Amorphous Solid ◽  
Amorphous Layer ◽  
Amorphous Solids ◽  
Solid Phase Epitaxy ◽  
Self Diffusion

AbstractA model of solid-phase epitaxial growth (SPEG), explaining enhancing effects of ion-irradiation and dopants, is presented. The crystallization is by the adjustment of atomic positions in the amorphous side of the crystalline/amorphous (c-a) interface due to self-diffusion in the amorphous solid, assisted by a freeenergy decrease associated with the transformation from the amorphous (a) to crystalline (c) phase. Irradiation and electrically active dopants increase the selfdiffusivity of a-phase by generating point defects in the amorphous layer and thus enhance crystallization. An expression for the velocity of epitaxial growth is derived. The low activation energy of ion-induced SPEG is due to recombination of point defects in the a-phase.

Effect of Buried Surface Structure on Solid Phase Epitaxy of GE on SI (111)-7×7

1993 ◽  
Vol 317 ◽  
Author(s):  
Olof C. Hellman
Keyword(s):  
Thin Film ◽  
Surface Structure ◽  
Surface Reconstruction ◽  
Silicon Surface ◽  
Room Temperature ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Rich Phase ◽  
One Dimensional ◽  
Surface Steps

ABSTRACTWe study the crystallization of a thin film of amorphous Ge deposited at room temperature on Si (111). Features of the silicon surface buried beneath the Ge film are shown to affect the rate of crystallization. In particular, solid phase epitaxy is observed to be enhanced at surface steps and defects in the surface reconstruction. It is further shown that one-dimensional crystallization patterns can be caused by impurity-Mediated crystallization. Precipitates of an impurity rich phase migrate in the plane of the film, leaving behind a crystalline trail. The Migration path of these precipitates is also dependent on the buried surface structure.

Rapid Thermal Annealing of GaAs Films on (001) Si Substrate Grown by Solid Phase Epitaxy Technique

1990 ◽  
Vol 202 ◽  
Author(s):  
W.K. Choo ◽  
K.I. Cho ◽  
J.Y. Lee ◽  
S.C. Park ◽  
O.J. Kwon
Keyword(s):  
Solid Phase ◽  
Substantial Improvement ◽  
Misfit Dislocations ◽  
Solid Phase Epitaxy ◽  
Si Substrate ◽  
Rapid Thermal Anneal ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Distributed Array ◽  
Gaas Films

ABSTRACTGaAs layers grown by solid phase epitaxy on (001) Si substrate were subjected to post-growth rapid thermal anneal (RTA) at 700, 800, and 900°C for 10s in a N2 atmosphere. Rutherford backscattering/channeling showed a substantial improvement in crystalline quality of GaAs epilayer after RTA at 800°C. After RTA at 900°C for 10s, stacking faults (and/or microtwins) were eliminated entirely, and the dislocation densities in both the interface region and the film interior were reduced. High-resolution transmission electron micrographs showed a significant change in misfit dislocation structure at the interface after RTA; namely, the 90° pure edge and 60° misfit dislocations were transformed to an evenly distributed array of 90° dislocations at the interface.

scholarly journals The role of antiphase boundaries during ion sputtering and solid phase epitaxy of Si(0 0 1)

2003 ◽  
Vol 538 (3) ◽  
pp. L471-L476 ◽  
Author(s):  
J.C. Kim ◽  
J.-Y. Ji ◽  
J.S. Kline ◽  
J.R. Tucker ◽  
T.-C. Shen
Keyword(s):  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Ion Sputtering ◽  
Antiphase Boundaries

Introduction to geomicrobiology

2018 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Fossil Fuels ◽  
Solid Phase ◽  
Direct Reduction ◽  
Iron Oxidation ◽  
Mineral Dissolution ◽  
Precipitation Process ◽  
Soluble Ions ◽  
Chemolithoautotrophic Bacteria ◽  
The Impact

Geomicrobiology, the marriage of geology and microbiology, is about the impact of microbes on Earth materials in terrestrial systems and sediments. Many geomicrobiological processes occur over long timescales. Even the slow growth and low activity of microbes, however, have big effects when added up over millennia. After reviewing the basics of bacteria–surface interactions, the chapter moves on to discussing biomineralization, which is the microbially mediated formation of solid minerals from soluble ions. The role of microbes can vary from merely providing passive surfaces for mineral formation, to active control of the entire precipitation process. The formation of carbonate-containing minerals by coccolithophorids and other marine organisms is especially important because of the role of these minerals in the carbon cycle. Iron minerals can be formed by chemolithoautotrophic bacteria, which gain a small amount of energy from iron oxidation. Similarly, manganese-rich minerals are formed during manganese oxidation, although how this reaction benefits microbes is unclear. These minerals and others give geologists and geomicrobiologists clues about early life on Earth. In addition to forming minerals, microbes help to dissolve them, a process called weathering. Microbes contribute to weathering and mineral dissolution through several mechanisms: production of protons (acidity) or hydroxides that dissolve minerals; production of ligands that chelate metals in minerals thereby breaking up the solid phase; and direct reduction of mineral-bound metals to more soluble forms. The chapter ends with some comments about the role of microbes in degrading oil and other fossil fuels.

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