Detection of Misfit Strain Relaxation in MBE Grown Si1-xGex Films by Dynamic Monitoring of Rheed Diffraction Features

1992 ◽  
Vol 263 ◽  
Author(s):  
J.W. Maes ◽  
O.F.Z. Schannen ◽  
J. Trommel ◽  
K. Werner ◽  
S. Radelaar ◽  
...  
Keyword(s):  
Detection Limit ◽  
Lattice Constant ◽  
Strain Relaxation ◽  
Ccd Camera ◽  
Misfit Strain ◽  
High Energy ◽  
Dynamic Monitoring ◽  
Rheed Pattern ◽  
High Energy Electron ◽  
Substrate Temperatures

ABSTRACTReflection high energy electron diffraction (RHEED) has been used to detect strain relaxation in SiGe during growth on <001>- oriented Si for various layer compositions and substrate temperatures. The RHEED-technique permits the dynamic monitoring of the in-plane lattice constant of the growing layer by measuring the distance between diffraction features. The actual RHEED pattern is recorded by a CCD camera and subsequently processed in real time by a computer. This way, the layer relaxation can be followed conveniently; a detection limit for a variation in the lattice constant of Δa/a=5.10−4 has been obtained.

scholarly journals Evidence of 2D-3D transition during the first stages of GaN growth on AlN

1997 ◽  
Vol 2 ◽  
Author(s):  
F. Widmann ◽  
B. Daudin ◽  
G. Feuillet ◽  
Y. Samson ◽  
M. Arlery ◽  
...  
Keyword(s):  
Smooth Surface ◽  
Molecular Beam ◽  
Growth Parameters ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
High Energy ◽  
Rheed Pattern ◽  
High Energy Electron ◽  
Island Coalescence

In order to identify the strain relaxation mechanism, Molecular Beam Epitaxy of wurtzite GaN on AlN was monitored in situ using Reflection High Energy Electron Diffraction (RHEED). In the substrate temperature range between 620°C and 720°C, a Stransky-Krastanov (SK) transition was evidenced, resulting in a 2D-3D transition after completion of 2 monolayers, with subsequent coalescence of 3D islands, eventually resulting in a smooth surface. Quantitative analysis of the RHEED pattern allowed us to determine that island formation is associated with elastic relaxation. After island coalescence, a progressive plastic relaxation is observed. The size and density of 3D islands was varied as a function of the growth parameters. AFM experiments revealed that the size of the GaN islands, about 8 nm large and 2 nm high, was small enough to expect quantum effects. It was found that capping of the islands by AlN resulted in a smooth surface after deposition of a few monolayers allowing us to grow a »superlattice» of islands by periodically repeating the process.

Epitaxial growth of BaO and SrO with new crystal structures using mass-separated low-energy O+ beams

1993 ◽  
Vol 8 (2) ◽  
pp. 321-323 ◽  
Author(s):  
Ryusuke Kita ◽  
Takashi Hase ◽  
Hiromi Takahashi ◽  
Kenichi Kawaguchi ◽  
Tadataka Morishita
Keyword(s):  
Lattice Constant ◽  
High Energy ◽  
Low Energy ◽  
Diffraction Reflection ◽  
High Energy Electron ◽  
Bulk Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Cubic Structure

The growth of BaO and SrO on SrTiO3(100) substrates using mass-separated low-energy (50 eV) O+ beams has been studied using x-ray diffraction, reflection high-energy electron diffraction, and high-resolution transmission electron microscopy. It was found that the BaO and SrO films have been epitaxially grown with new structures different from those of corresponding bulk crystals: The BaO films have a cubic structure with a lattice constant of 4.0 Å, and the SrO films have a tetragonal structure with a lattice constant of a = 3.7 Å parallel to the substrate and with c = 4.0 Å normal to the substrate.

Analysis of Reflection High Energy Electron Diffraction Pattern of Silicon Carbide Grown on Silicon

1995 ◽  
Vol 399 ◽  
Author(s):  
G. Teichert ◽  
J. Pezoldt ◽  
V. Cimalla ◽  
O. Nennewitz ◽  
L. Spiess
Keyword(s):  
Silicon Carbide ◽  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Process Parameters ◽  
Electron Diffraction Pattern ◽  
Lattice Relaxation ◽  
High Energy ◽  
Morphology Evolution ◽  
Rheed Pattern ◽  
High Energy Electron

ABSTRACTRHEED pattern of SiC layers on both (100) and (111)Si grown by carbonization were studied. Different deviations from the single crystalline structure were found ranging from twinning up to changes in the orientation and textured growth. Special attention was drawn on lattice relaxation and morphology evolution during the growth of the formed SiC. Relationships between the occurrence of typical RHEED pattern and the morphology and process parameters are presented.

Slow Decay of Reflection High Energy Electron Diffraction Oscillations in Cal1-xMgxF2

1996 ◽  
Vol 441 ◽  
Author(s):  
Mitsuhiro Kushibe ◽  
Yuriy V. Shusterman ◽  
Nikolai L. Yakovlev ◽  
Leo J. Schowalter
Keyword(s):  
Phase Separation ◽  
Electron Diffraction ◽  
Lattice Constant ◽  
Room Temperature ◽  
High Energy ◽  
Energy Electron ◽  
Scanning Tunneling ◽  
High Energy Electron ◽  
Tunneling Microscopy ◽  
Slow Decay

AbstractMagnesium is incorporated into the growth of Ca1-xMgxF2 to reduce the lattice constant of fluorite (CaF2) which is 0.6% larger than that of Si at room temperature. When grown epitaxially on Si(111) substrates at 300°C, the lattice constant of the alloy became smaller than that of Si by 1.5% when the Mg concentration was around 20%. At higher Mg concentrations, the lattice constant did not decrease any further. This invariability of the lattice constant was caused by a phase separation of the Ca1-xMgxF2 layer into a Mg-rich region and a Mg-deficient region. When the growth temperature was increased, the critical Mg concentration for the phase separation became smaller. When Ca1-xMgxF2 was grown on vicinal Si(111) substrates, the reflection high energy electron diffraction (RHEED) intensity oscillations reflected no change in the composition, suggesting segregation of a Mg-rich phase along the steps. Nevertheless, the oscillations in the intensity of the specular spot for Ca1-xMgxF2 lasted longer than those observed for pure CaF2, suggesting a flatter surface for the alloy. Scanning tunneling microscopy (STM) observations support this model.

Rheed Observation of Lattice Relaxation During Ge/Si(O01) Heteroepitaxy

1989 ◽  
Vol 148 ◽  
Author(s):  
Kazushi Miki ◽  
Kunihiro Sakamoto ◽  
Tsunenori Sakamoto
Keyword(s):  
Electron Diffraction ◽  
Lattice Constant ◽  
Growth Temperature ◽  
Lattice Relaxation ◽  
High Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Plane Lattice

ABSTRACTWe report the dynamic RHEED (reflection high energy electron diffraction) observation during Ge/Si(001) heteroepitaxy at various growth temperatures. The RHEED intensityanalysis and the in-plane lattice constant analysis reveal a growth fashion and lattice relaxation. Both of them depend strongly on growth temperature.

An In-Situ Study of the Segregation and the Strain Relaxation During Growth of Gold and Nickel Ultrathin Films

1999 ◽  
Vol 562 ◽  
Author(s):  
S. Labat ◽  
P. Gergaud ◽  
O. Thomas ◽  
B. Gilles ◽  
A. Marty
Keyword(s):  
Ultrathin Films ◽  
Strain Relaxation ◽  
High Energy ◽  
Stress And Strain ◽  
High Energy Electron ◽  
In Situ Study ◽  
Real Time Measurement ◽  
Ultrathin Layers ◽  
Large Asymmetry

ABSTRACTWe report on in-situ real time measurement of both stress and strain during growth of ultrathin layers, with submonolayer sensitivity. The in-plane parameter is measured by Reflection High Energy Electron Diffraction (RHEED) and the stress is determined via the measurement of the curvature. The system studied is Au/Ni (i.e. Au on Ni and Ni on Au). We have evidenced a large asymmetry in the two different growths: Au (on Ni) shows a progressive elastic strain relaxation whereas Ni (on Au) exhibits a strong interplay between the stress and the interfacial mixing.

Energy-filtered reflection electron microscopy and reflection high-energy electron diffraction on Zeiss 912 TEM

1993 ◽  
Vol 51 ◽  
pp. 580-581
Author(s):  
JINGYUE LIU
Keyword(s):  
Electron Microscopy ◽  
Electron Diffraction ◽  
Ccd Camera ◽  
Chromatic Aberration ◽  
High Energy ◽  
Energy Electron ◽  
Objective Lens ◽  
High Energy Electron ◽  
Resolution Limit ◽  
Reflection Electron Microscopy

In reflection electron microscopy (REM) and reflection high energy electron diffraction (RHEED) the average path length of the elastically scattered electrons in the crystal ranges from 10 -100 nm and a significant portion of the electrons in the RHEED pattern spots used for imaging is inelastically scattered. The excitations of surface plasmons, bulk plasmons and valence electrons involves energy losses of 10 ∽30 eV. Thus the image contrast and resolution in REM are degraded due to chromatic aberration of the objective lens. The use of energy filters in a TEM should offer significant improvement in resolution and contrast of REM images. We present here some new results on the investigation of resolution limit and contrast mechanisms in energy filtered REM images.The experiments were performed on a Zeiss 912 TEM fitted with an Omega magnetic imaging energy filter. Digital RHEED patterns and REM images were acquired into 1024 pixels by 1024 pixels via a Gatan 679 CCD camera fitted to the microscope.

Initial Stages of Reactions between Monolayer Fe and Si(001) Surfaces

1995 ◽  
Vol 402 ◽  
Author(s):  
M. Hasegawa ◽  
N. Kobayashi ◽  
N. Hayashi
Keyword(s):  
Electron Diffraction ◽  
Room Temperature ◽  
High Energy ◽  
Rheed Pattern ◽  
High Energy Electron ◽  
Type B ◽  
Ion Scattering ◽  
Temperature Deposition ◽  
Hydrogen Termination

AbstractReactions between 1.5 monolayer(ML) Fe deposited on Si(001)-2 × 1 and -dihydride surfaces were studied in situ by reflection high-energy electron diffraction and time-of-flight ion scattering spectrometry with the use of 25 keV H ions. The reactions between Fe and Si which were successively deposited on Si(001)-dihydride surface were also studied. After the room temperature deposition Fe reacted with Si(001)-2 × 1 substrate resulting in the formation of polycrystalline Fe5Si3. By annealing to 560∼650°C composite heteroepitaxial layer of both type A and type B β -FeSi2 was formed. On the dihydride surface polycrystalline Fe was observed after 1.5ML Fe deposition at room temperature, and reaction between Fe and Si(001)-dihydride surface is not likely at room temperature. We observed 3D rough surface when we deposited only Fe layer on the dihydride surface and annealed above 700°C. The hydrogen termination of Si(001) surface prevents the deposited Fe from diffusing into the substrate below 500°C, however the annealing above 710°C leads to the diffusion. We obtained 2D ordered surface, which showed 3 × 3 RHEED pattern as referenced to the primitive unreconstructed Si(O01) surface net, when we deposited 2.5ML Fe and 5.8ML Si successively onto Si(001)-dihydride surface and annealed to 470°C.

Growth of Si on Ge(001)2×l by gas-source molecular beam epitaxy

1993 ◽  
Vol 51 ◽  
pp. 806-807
Author(s):  
H.Z. Xiao ◽  
R. Tsu ◽  
I.M. Robertson ◽  
H.K. Birnbaum ◽  
J.E. Greene
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Strain Relaxation ◽  
Misfit Strain ◽  
High Energy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Gas Source ◽  
High Quality Result ◽  
Strained Layer Superlattices

The growth of SiGe strained-layer superlattices (SLS) has been received considerable attention due to the electronic and optoelectronic properties of these layers. In addition, these structures offer tantalizing possibilities for "band gap engineering" through the use of strain and chemically ordered alloys. The remaining barriers to grow the SiGe SLS structures with high quality result from the generation of large densities of defects, such as dislocations, twins, stacking faults, etc., at the heterointerfaces arising from the misfit strain relaxation. Other problems associated with the growth of the SiGe SLS structures are segregation and low incorporation of the dopants and inter-diffusion of Si and Ge. In the present study, the inter-mixing of Si and Ge and the generation of the defects in Si epilayers grown on Ge(001)2×1 at 550 °C by gas-source molecular beam epitaxy (MBE) from Si2H6 were studied using transmission electron microscopy (TEM), in-situ reflection high-energy electron diffraction (RHEED), scanning tunneling microscopy (STM) and electron energy-loss spectroscopy (EELS).

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