Strains and Relaxations Near metal Alumlnide/Semiconductor Interfaces

1991 ◽  
Vol 226 ◽  
Author(s):  
W.W. Gerberich ◽  
J.E. Angelo ◽  
R.R. Keller ◽  
A.M. Wowchak ◽  
P.I. Cohen
Keyword(s):  
Strain Distribution ◽  
Strain Relaxation ◽  
High Energy ◽  
Lattice Parameter ◽  
Layer Growth ◽  
Layer By Layer ◽  
Material Interfaces ◽  
Kinetic Measurements ◽  
Film Substrate ◽  
The Impact

AbstractMechanisms and phenomena of strain relaxation at bi-material interfaces have been studied for over half a century. The details, however, and limiting kinetics, thermodynamics and mechanics are still being sorted out - particularly for large misfit systems. Three techniques are required to accurately portray strain distributions during and after epitaxial growth: RHEED, TEM and SACP. Reflection high energy electron diffraction (RHEED) is used to measure the lattice parameter during growth. Both transmission electron microscopy (TEM) and selected area electron channeling pattern (SACP) analysis are necessary to identify the defects and the strain distribution. These techniques have been applied to NiAl and FeAl grown by MBE on GaAs with a thin AlAs buffer layer. It is shown that both island and layer by layer growth can occur with the corresponding defects being remarkably similar in character. From a combined Moiré, HREM and computer simulation, the dislocation character is assessed. Both <100> dislocations from half-loops or island edges may occur providing only partial relaxation of the film-substrate systems. The impact of the remaining elastic strain distribution on kinetic measurements of dislocation velocities is discussed.

Combinatorial Molecular Layer Epitaxy of Hf Based Phosphor Oxides

2001 ◽  
Vol 700 ◽  
Author(s):  
N. Arai ◽  
T. W. Kim ◽  
H. Kubota ◽  
Y. Matsumoto ◽  
H. Koinuma
Keyword(s):  
Molecular Layer ◽  
High Energy ◽  
Layer Growth ◽  
Laser Deposition ◽  
Layer By Layer ◽  
High Energy Electron ◽  
X Ray ◽  
Substrate Interaction ◽  
Film Substrate

AbstractA series of MHfO3: Tm (M =Ca, Sr and Ba) composition spread films and superlattices (SLs) were quickly fabricated on SrTiO3 (001) substrate in the molecular layer-by-layer growth using combinatorial pulsed laser deposition (PLD) under in-situ reflection high-energy electron diffraction (RHEED) monitoring. Crystal structures and luminescence properties of composition-spread and SLs were evaluated by the concurrent X-ray diffractometer and cathode luminescence (CL), respectively. CL properties of the films were found strongly dependent on their composition and stacking sequence. Possible effect of the stress due to the film-substrate interaction on the CL property is discussed.

Theoretical analysis of reflection high-energy electron diffraction (RHEED) and reflection high-energy positron diffraction (RHEPD) intensity oscillations expected for the perfect layer-by-layer growth

2015 ◽  
Vol 71 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Zbigniew Mitura
Keyword(s):  
Theoretical Models ◽  
High Energy ◽  
Layer Growth ◽  
Simplified Model ◽  
Layer By Layer ◽  
High Energy Electron ◽  
Realistic Potential ◽  
Simplified Approach ◽  
Electrons And Positrons ◽  
Analytical Formulas

Predictions from two theoretical models, allowing one to determine the phase of intensity oscillations, are compared for reflected beams of electrons and positrons. Namely, results of the precise dynamical calculations are compared with results obtained using a simplified approach. Within the simplified model, changes in the specularly reflected beam intensity, expected to occur during the deposition of new atoms, are described with the help of interfering waves and the effect of refraction, and respective approximate analytical formulas are employed to determine the phase of the oscillations. It is found that the simplified model is very useful for understanding the physics ruling the appearance of intensity oscillations. However, it seems that the model with the realistic potential is more suitable for carrying out interpretations of experimental data.

Atomic Layer and Unit-Cell Layer Growth of (Ca,Sr)CuO2 and Bi2Sr2Can-1CunO2n+4 Thin Films by Laser Molecular Bean Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
Masaki Kanai ◽  
Tomoji Kawai ◽  
Takuya Matsumoto ◽  
Shichio Kawai
Keyword(s):  
Thin Films ◽  
Diffraction Pattern ◽  
Cell Layer ◽  
Atomic Layer ◽  
High Energy ◽  
Layer Growth ◽  
Unit Cell ◽  
Layer By Layer ◽  
Diffraction Intensity

ABSTRACTThin films of (Ca,Sr)CuO2 and Bi2Sr2Can-1CunO2n+4 are formed by laser molecular beam epitaxy with in-situ reflection high energy electron diffraction observation. The diffraction pattern shows that these materials are formed with layer-by-layer growth. The change of the diffraction intensity as well as the analysis of the total diffraction pattern makes It possible to control the grown of the atomic layer or the unit-cell layer.

Bismuth-Induced Layer-by-Layer Growth in the Homoepitaxial Growth of Fe(100)

2002 ◽  
Vol 749 ◽  
Author(s):  
Masao Kamiko ◽  
Hiroaki Chihaya ◽  
Hiroyuki Mizuno ◽  
Junhua Xu ◽  
Isao Kojima ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Surface Segregation ◽  
High Energy ◽  
Layer Growth ◽  
Growth Behavior ◽  
Layer By Layer ◽  
High Energy Electron ◽  
Optimum Amount ◽  
Homoepitaxial Growth ◽  
Strong Surface

ABSTRACTWe have investigated the effect of Bi on the homoepitaxial growth of Fe(100) by means of reflection high-energy electron diffraction (RHEED). It was clearly found that Bi induces layer-by-layer growth of Fe on Fe(100)-c(2×2)O reconstruction surface. The result of the dependence of the growth behavior as a function of Bi layer thickness suggests that there is optimum amount of Bi surfactant layer that induces the smoother layer-by-layer growth. A strong surface segregation of Bi was found at the top of surface and acts as a surfactant by promoting the interlayer transport.

Rheed Intensity Oscillation During Layer-by-Layer Growth of Bi-Sr-Ca-Cu-O Thin Films

1992 ◽  
Vol 275 ◽  
Author(s):  
K. Yoshikawa ◽  
N. Sasaki
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
High Energy ◽  
Layer Growth ◽  
Layer By Layer ◽  
Two Dimensional ◽  
Growth Interruption ◽  
Layer Deposition ◽  
Unit Cells ◽  
Layered Growth

ABSTRACTUsing in-situ reflection high-energy electron diffraction (RHEED), we studied the growth of Bi-Sr-Ca-Cu-O (BSCCO) thin films prepared by reactive evaporation using layer-by-layer deposition. Bi2Sr2CaCu2Ox(2212) tends to be grown three-dimensionally if it is grown directly on (100) SrTiO3, in contrast to Bi2Sr2CuOx(2201) which is easily grown two-dimensionally on SrTiO3. Two-dimensional 2212 growth can be realized, if a buffer layer of 2201 is deposited on (100) SrTiO3 and growth interruption is utilized after SrO layer deposition. A buffer layer of only two 2201 unit cells improved the surface crystallinity of the substrate for the epitaxial growth of 2212. Growth interruption for two minutes after the 2nd SrO layer in the half unit cell is necessary to keep two-dimensional layered growth. The resulting Tc (zero) is 76 K and Jc (at 4.2 K) is 1.5 × 106 (A/cm2) with these epitaxial films.

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.

Measurement of the Strain Distribution in Notch Tip Hydrides With High Energy X-Ray Diffraction and the Impact on Overload Modeling

2010 ◽  
Author(s):  
Matthew Kerr ◽  
Stephanie Tracy ◽  
Mark R. Daymond ◽  
Richard A. Holt ◽  
Jonathon D. Almer
Keyword(s):  
Finite Element ◽  
Strain Distribution ◽  
Process Zone ◽  
High Energy ◽  
X Ray Diffraction ◽  
Strain Fields ◽  
X Ray ◽  
Pressure Tubes ◽  
Notch Tip ◽  
The Impact

The formation of notch-tip hydrides in CANDU® Zr-2.5Nb pressure tubes can significantly reduce their resistance to fracture, particularly during overload conditions. This paper outlines recent high energy X-ray diffraction measurements of notch tip strain fields in Zr-2.5Nb specimens, during both hydride growth and overload. The use of this data to validate continuum Finite Element (FE) and possible inclusion in ‘Process Zone’ models of hydride fracture are also discussed.

Oxygen Pressure Dependence of Morphology of Morphology of La2-xSrxCuO4 Ultra-Thin Films

1997 ◽  
Vol 11 (21n22) ◽  
pp. 981-987
Author(s):  
H. Q. Yin ◽  
T. Arakawa ◽  
Y. Kaneda ◽  
T. Yoshikawa ◽  
N. Haneji ◽  
...  
Keyword(s):  
Thin Films ◽  
Pressure Dependence ◽  
Film Growth ◽  
Ambient Pressure ◽  
High Energy ◽  
Layer Growth ◽  
Growth Mode ◽  
Layer By Layer ◽  
Island Growth ◽  
Experimental Conditions

La 2-x Sr x CuO 4 ultra-thin films with thickness 200 Å were fabricated by pulsed laser deposition method in oxygen ( O 2) atmosphere. The morphology of deposited films was investigated by reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM) and scanning electronic microscopy (SEM). The strong oxygen ambient pressure dependence of film morphology was observed. In high oxygen ambient pressure, the film growth is dominated by island growth mode. The results imply that the experimental conditions of oxygen ambient pressure and substrate temperature are critical for the layer-by-layer growth mode.

Growth of epitaxial β-FeSi2 thin films by pulsed laser deposition on silicon (111)

1994 ◽  
Vol 9 (11) ◽  
pp. 2733-2736 ◽  
Author(s):  
C.H. Olk ◽  
O. P. Karpenko ◽  
S. M. Yalisove ◽  
G. L. Doll ◽  
J.F. Mansfield
Keyword(s):  
Electron Diffraction ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
High Energy ◽  
Layer Growth ◽  
Laser Deposition ◽  
Electron Diffraction Data ◽  
Layer By Layer ◽  
Material System ◽  
Epitaxial Relationship

Epitaxial films of semiconducting iron disilicide (β-FeSi2) have been grown by pulsed laser deposition. We find that pulsed laser deposition creates conditions favorable to the formation of films with the smallest geometric misfit possessed by this material system. In situ reflection high energy electron diffraction results indicate a layer by layer growth of the silicide. Analysis of transmission electron diffraction data has determined that the films are single phase and that this growth method reproduces the epitaxial relationship: β-FeSi2 (001) ‖ Si(111).

Reflection High Energy Electron Diffraction Studies of the Growth of DyBa2Cu3O7−x Films and Structures Grown on SrTiO3 Substrates

1992 ◽  
Vol 275 ◽  
Author(s):  
V. S. Achutharaman ◽  
N. Chandrasekhar ◽  
A. M. Goldman
Keyword(s):  
Electron Diffraction ◽  
Specular Reflection ◽  
Growth Conditions ◽  
High Energy ◽  
Layer Growth ◽  
Energy Electron ◽  
Layer By Layer ◽  
High Energy Electron ◽  
Epitaxial Relationship ◽  
Superlattice Structures

ABSTRACTIntensity oscillations of the specular reflection high energy electron diffraction (RHEED) beam contain useful information on the mode of growth and the evolving structure of thin films. We present RHEED studies of the growth of DyBa2Cu3O7−x films and DyBa2Cu3O7−x/DY2O3/DyBa2Cu3O7−x structures on SrTiO3; substrates deposited by ozone-assisted molecular beam epitaxy. The effect of substrate temperature, ozone flux and surface step densities on the epitaxial relationship and evolving microstructure will be discussed. The strong damping of the oscillations and identical time periods under different nuoleation and growth conditions suggest that the intensity oscillations are a consequence of to diffuse scattering from step edges rather than a layer-by-layer growth mode. It was also found that Dy2O3 can be used to fabricatee tri-layer type structures but not superlattice structures.

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