On the breakdown of layer-by-layer growth and the spontaneous nucleation of misfit dislocations in molecular-beam epitaxially grown GeSi/Si

1993 ◽  
Vol 11 (3) ◽  
pp. 889 ◽  
Author(s):  
D. D. Perovic
Keyword(s):  
Molecular Beam ◽  
Layer Growth ◽  
Misfit Dislocations ◽  
Layer By Layer ◽  
Spontaneous Nucleation

Epitaxial Solid-Solution Films of Immiscible MgO and CaO

1994 ◽  
Vol 341 ◽  
Author(s):  
E. S. Hellman ◽  
E. H. Hartford
Keyword(s):  
Solid Solution ◽  
Molecular Beam Epitaxy ◽  
Lattice Constant ◽  
Solid Solutions ◽  
Molecular Beam ◽  
Building Blocks ◽  
Layer Growth ◽  
Growth Mode ◽  
Miscibility Gap ◽  
Layer By Layer

AbstractMetastable solid-solutions in the MgO-CaO system grow readily on MgO at 300°C by molecular beam epitaxy. We observe RHEED oscillations indicating a layer-by-layer growth mode; in-plane orientation can be described by the Matthews theory of island rotations. Although some films start to unmix at 500°C, others have been observed to be stable up to 900°C. The Mgl-xCaxO solid solutions grow despite a larger miscibility gap in this system than in any system for which epitaxial solid solutions have been grown. We describe attempts to use these materials as adjustable-lattice constant epitaxial building blocks

Layer-by-Layer Growth of Bi-Sr-Ca-Cu-O Superconducting Films by Molecular Beam Epitaxy

1991 ◽  
Vol 30 (Part 1, No. 12B) ◽  
pp. 3900-3903 ◽  
Author(s):  
Takayuki Ishibashi ◽  
Yoshitaka Okada ◽  
Shin Yokoyama ◽  
Mitsuo Kawabe
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Superconducting Films ◽  
Layer Growth ◽  
Layer By Layer

Effects of Stress on Step Energies and Surface Roughness

MRS Bulletin ◽  
1996 ◽  
Vol 21 (4) ◽  
pp. 27-30 ◽  
Author(s):  
Christopher Roland
Keyword(s):  
Thin Films ◽  
Strain Relaxation ◽  
Three Dimensional ◽  
Layer Growth ◽  
Growth Mode ◽  
Misfit Dislocations ◽  
Layer By Layer ◽  
Strained Layers ◽  
The Subject ◽  
Growth Changes

Strain relaxation in lattice-mismatched, heteroepitaxial systems is one of the classic problems in materials physics, which has gained new urgency with the increased applications of strained layers in microelectronic systems. In general both the structure and the integrity of the thin films are strongly influenced by strain. For instance it has long been known that under strain, the growth changes from an initial layer-by-layer growth mode to one with three-dimensional islanding. In the seminal works of van der Merwe, and Matthews and Blakeslee, this change in growth mode is explained in terms of the introduction of strain-relieving misfit dislocations, which appear when the film has reached some critical thickness. Recently it has become clear that this change in growth mode can take place even without the introduction of misfit dislocations. Such dislocation-free coherent islanding, or “roughening,” has been observed experimentally both in Ge/Si and in InGaAs/GaAs systems. Furthermore recent experiments show that in Ge/Si(100) systems, the thin films display a curious asymmetry with respect to the sign of the strain: Films under compression roughen by forming coherent islands while those under tension remain relatively smooth. A possible mechanism behind this strain-induced type of roughening is the subject of this article.

Relationship Between Crystal Defects, Ge Outdiffusion and V/III Ratio in MOVPE Grown (001) GaAs/Ge

1993 ◽  
Vol 319 ◽  
Author(s):  
C. Frigeri ◽  
G. Atrolini ◽  
C. Pelosi ◽  
F. Longo
Keyword(s):  
Stacking Faults ◽  
Layer Growth ◽  
Crystal Defects ◽  
Misfit Dislocations ◽  
Layer By Layer ◽  
Island Growth ◽  
Planar Defects ◽  
Fault Density ◽  
Unintentional Doping ◽  
Enhanced Mobility

AbstractTwo regimes of defect generation have been found in MOVPE GaAs/Ge layers upon changing the V/III ratio between 1.3 and 11.8. For low V/III ratio the layers contained misfit dislocations along with stacking faults that had been generated by dissociation of the misfit dislocations. The stacking fault density increased with decreasing V/III ratio. This might be explained by an enhanced mobility of the dissociated partials due the reduced unintentional doping of the layer caused by reduced Ge outdiffusion from the substrate when V/III is small. The secon regime corresponds to high V/III ratios and is characterized by the absence of misfit dislocations and the presence of a high density of planar defects. This means that breakdown of the 2D layer-by-layer growth occurred and 3D island growth prevailed.

Molecular layer-by-layer growth of SrTiO3 and BaTiO3 films by laser molecular beam epitaxy

1996 ◽  
Vol 41 (1) ◽  
pp. 134-137 ◽  
Author(s):  
T. Maeda ◽  
G.H. Lee ◽  
T. Ohnishi ◽  
M. Kawasaki ◽  
M. Yoshimoto ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Molecular Layer ◽  
Layer Growth ◽  
Layer By Layer ◽  
Laser Molecular Beam Epitaxy

Molecular Dynamics Studies of Semiconductor Thin Films and Interfaces

1987 ◽  
Vol 94 ◽  
Author(s):  
Marcia H. Grabow ◽  
George H. Gilmer
Keyword(s):  
Molecular Dynamics ◽  
Energy State ◽  
Layer Growth ◽  
Metastable Equilibrium ◽  
Free Energy Barrier ◽  
Misfit Dislocations ◽  
Layer By Layer ◽  
3 Dimensional ◽  
Smooth Film ◽  
The Stability

ABSTRACTThe structure and stability of thin epitaxial films have been investigated using molecular dynamics computer simulations. One issue of interest is the stability of a smooth film relative to 3-dimensional clusters. The simulation results show that the uniform film is never the lowest energy state for a system with finite misfit. However, the uniform film, produced in a layer-by-layer growth mode, can persist in a metastable state at substantial misfits, e.g. 10% at 1/2 the melting point. This is a result of the large nucleation barrier to the formation of clusters.The second issue is the quality of the interface between the film and the substrate. At equilibrium, the critical thickness for the introduction of misfit dislocations is larger for films on the diamond cubic (100) substrate than on the (111), and differs from predictions based on continuum mechanics. We find that coherent films remain in metastable equilibrium far beyond the critical misfit calculated for full equilibrium, because a large free energy barrier inhibits the introduction of misfit dislocations.

Auto Feeding Epitaxial Growth of Oxide Thin Film without Oxidant

2001 ◽  
Vol 666 ◽  
Author(s):  
Kazuo Shimoyama ◽  
Kousuke Kubo ◽  
Tatsuro Maeda ◽  
Kikuo Yamabe
Keyword(s):  
Molecular Beam ◽  
Oxygen Supply ◽  
High Energy ◽  
Layer Growth ◽  
Oxide Thin Film ◽  
Layer By Layer ◽  
High Energy Electron ◽  
Low Oxygen ◽  
High Quality ◽  
Deposited Films

ABSTRACTHigh-quality thin films of BaTiO3 and SrTiO3 on SrTiO3 substrate were obtained by shutting off the oxygen supply during growth. Epitaxial growths were carried out with molecular-beam epitaxy (MBE) under extremely low oxygen partial pressure (pO2 < 1×10−8 Pa). Although only Ba(Sr) and Ti metals were supplied without introducing oxidant during the growth, clear reflection high-energy electron diffraction (RHEED) intensity oscillations from layer-by-layer growth were observed. The deposited films were found to have approximately stoichiometric compositions of BaTiO3 and SrTiO3. Oxygen was automatically fed from the substrate during the growths. It was found that the BaTiO3/SrTiO3 interface was abrupt without intermixing, despite a considerable amount of oxygen seems to have moved from the substrate to the film through the interface.

Layer by Layer Growth of Bi-Sr-Ca-Cu-O by Molecular Beam Epitaxy

1991 ◽  
Author(s):  
Takayuki Ishibashi ◽  
Yoshitaka Okada ◽  
Shin Yokoyama ◽  
Mitsuo Kawabe
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Layer Growth ◽  
Layer By Layer
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