Electron Channeling Analysis of Elastic Strains in InGaAs Thin Films

1989 ◽  
Vol 160 ◽  
Author(s):  
R. Keller ◽  
W. Zielinski ◽  
W.W. Gerberich ◽  
J.A. Kozubowski
Keyword(s):  
Thin Films ◽  
Elastic Strain ◽  
Lattice Mismatch ◽  
Electron Channeling ◽  
Gaas Substrates ◽  
Strain Determination ◽  
Film Substrate ◽  
Line Positions ◽  
Elastic Strain Field ◽  
Elastic Strains

AbstractInx Ga1-x As thin films were grown by MBE on (001) GaAs substrates. The associated 1% lattice mismatch resulted in the development of an elastic strain field in the systems. Electron channeling patterns (ECP) were then obtained from these samples in an SEM at different accelerating voltages, allowing data to be obtained over various information depths within the samples while keeping them intact. The ECPs showed sensitivity to the elastic strains both parallel and perpendicular to the film/substrate interface. Certain high order Laue zone (HOLZ) line positions showed good sensitivity to the Poisson strain in the films due to a rotation of atomic planes. These line positions varied with film thickness and distance from the interface. The technique shows promise as a tool for relatively easy elastic strain determination. Its limitations will also be discussed.

Microstructure of SrTiO3 Thin Films as Single Layer and Incorporated in Yba2Cu3O7-x/SrTiO3 Multilayers

1995 ◽  
Vol 401 ◽  
Author(s):  
L. Ryen ◽  
E. Olssoni ◽  
L. D. Madsen ◽  
C. N. L. Johnson ◽  
X. Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Lattice Mismatch ◽  
Single Layer ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Interfacial Dislocations ◽  
The Individual ◽  
Film Substrate

AbstractEpitaxial single layer (001) SrTiO3 films and an epitaxial Yba2Cu3O7-x/SrTiO3 multilayer were dc and rf sputtered on (110)rhombohedral LaAIO3 substrates. The microstructure of the films was characterised using transmission electron microscopy. The single layer SrTiO3 films exhibited different columnar morphologies. The column boundaries were due to the lattice mismatch between film and substrate. The boundaries were associated with interfacial dislocations at the film/substrate interface, where the dislocations relaxed the strain in the a, b plane. The columns consisted of individual subgrains. These subgrains were misoriented with respect to each other, with different in-plane orientations and different tilts of the (001) planes. The subgrain boundaries were antiphase or tilt boundaries.The individual layers of the Yba2Cu3O7-x/SrTiO3 multilayer were relatively uniform. A distortion of the SrTiO3 unit cell of 0.9% in the ‘001’ direction and a Sr/Ti ratio of 0.62±0.04 was observed, both in correspondence with the single layer SrTiO3 films. Areas with different tilt of the (001)-planes were also present, within each individual SrTiO3 layer.

Effect of Strain on the Tunability of Highly (100) Oriented Mn-doped Barium Strontium Stannate Titanate Thin Films

2007 ◽  
Vol 1034 ◽  
Author(s):  
Shengbo Lu ◽  
Ngai Wing Li ◽  
Zhengkui Xu
Keyword(s):  
Thin Films ◽  
Elastic Strain ◽  
Lattice Mismatch ◽  
Nominal Composition ◽  
Mn Doping ◽  
Inhomogeneous Strain ◽  
Barium Strontium ◽  
Strontium Stannate ◽  
Tunable Device ◽  
Mn Doped

AbstractHighly (100)-oriented Mn-doped barium strontium stannate titanate thin films of a nominal composition (Ba0.7Sr0.3)(Sn0.2Ti0.8-xMnx)O3(Mn-BSSnT) (x=0%, 0.2%, 0.4%, 0.6% and 1%), were fabricated by pulsed laser deposition on (La0.7Sr0.3)O3/LaAlO3substrates. Both elastic strain and inhomogeneous strain were measured by x-ray diffraction techniques. Relationship between the strain and the dielectric properties of the Mn-BSSnT thin films were systematically investigated as a function of the Mn content. Our results show that the tunability is dependent upon not only the elastic strain induced by thermal expansion coefficient and lattice mismatch between the thin film and the substrate but also inhomogeneous strain induced by Mn doping. The tunability decreases with increasing inhomogeneous strain and can be easily manipulated by changing Mn doping content, which is beneficial to real tunable device applications.

scholarly journals Аналитическое выражение для распределения упругой деформации, создаваемой включением в форме многогранника с произвольной собственной деформацией

2018 ◽  
Vol 60 (9) ◽  
pp. 1761
Author(s):  
А.В. Ненашев ◽  
А.В. Двуреченский
Keyword(s):  
Strain Field ◽  
Elastic Strain ◽  
Lattice Mismatch ◽  
Displacement Vector ◽  
Three Dimensional ◽  
Infinite Medium ◽  
Displacement Vector Field ◽  
Polyhedral Shape ◽  
Three Dimensional Configuration ◽  
Elastic Strain Field

AbstractAnalytical expressions for the displacement vector, stain tensor, and Eshelby tensor have been obtained in the case where an inclusion in an elastically isotropic infinite medium has a polyhedral shape. The eigenstrain (e.g., the lattice mismatch) is assumed to be constant inside the inclusion but not obligatorily hydrostatic. The obtained expressions describe the strain both inside the inclusion and in its environment. It has been shown that a complex three-dimensional configuration of the elastic strain field (as well as of the displacement vector field) is reduced to a combination of simple functions having an illustrative physical and geometrical interpretation.

Microstructure of laser-ablated superconducting La2CuO4Fx thin films on SrTiO3

2001 ◽  
Vol 16 (11) ◽  
pp. 3309-3316 ◽  
Author(s):  
G. Kong ◽  
M. O. Jones ◽  
J. S. Abell ◽  
P. P. Edwards ◽  
S. T. Lees ◽  
...  
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Microstructural Analysis ◽  
Stacking Faults ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Elemental Fluorine ◽  
Deposit Surface ◽  
Film Substrate ◽  
Post Deposition

Thin films of lanthanum cuprate were grown on SrTiO3 substrates by pulsed laser deposition and made superconducting (Tc ∼ 38 K) through the process of post-deposition fluorination using elemental fluorine. A microstructural analysis showed that the [110] zone of the film grows parallel to the [100] zone of the SrTiO3 substrate, reducing the lattice mismatch from 37.5% to 2.4%. At the film–substrate interface there is an intermediate layer 3–4 nm thick and twin-related grains emanate from this region. Stacking faults are present in the bulk of the film, with misoriented subgrains present at the deposit surface.

Variant structure in metal-organic-chemical-vapor-deposition-derived SnO2 thin films on sapphire (0001)

1995 ◽  
Vol 10 (6) ◽  
pp. 1516-1522 ◽  
Author(s):  
Donhang Liu ◽  
Q. Wang ◽  
H.L.M. Chang ◽  
Haydn Chen
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Organic Chemical ◽  
Metal Organic ◽  
Film Substrate ◽  
Organic Chemical Vapor Deposition

Tin oxide (SnO2) thin films were deposited on sapphire (0001) substrate by metal-organic chemical vapor deposition (MOCVD) at temperatures of 600 and 700 °C. The microstructure of the deposited films was characterized by x-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). At the growth conditions studied, films were single-phase rutile and epitaxial, but showed variant structures. Three distinct in-plane epitaxial relationships were observed between the films and the substrate. A crystallographic model is proposed to explain the film morphology. This model can successfully predict the ratio of the width to the length of an averaged grain size based upon the lattice mismatch of the film-substrate interface.

Pulsed Laser Deposition of BaxSr1-xTiO3 Thin Films for Frequency Agile Microwave Electronics

1998 ◽  
Vol 526 ◽  
Author(s):  
W. Chang ◽  
J. S. Horwitz ◽  
J. M. Pond ◽  
S. W. Kirchoefer ◽  
D B. Chrisey
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Dielectric Behavior ◽  
Laser Deposition ◽  
Film Stress ◽  
Bst Films ◽  
The Difference ◽  
Film Substrate

AbstractOriented, single phase thin films (~5000Å thick) of BaxSr1-xTiO3 (BST) have been deposited on to (100) MgO and LaAlO3 (LAO) single crystal substrates using pulsed laser deposition (PLD). A strong correlation is observed between the microstructure of the deposited film and the dielectric tuning and loss at microwave frequencies. Microstructural defects observed in as deposited films include strain, due to film substrate lattice mismatch and oxygen and cation vacancies. Compensation of the ablation target with excess Ba and Sr is observed to increase the dielectric constant and to reduce the dielectric loss. Post-deposition, bomb annealing of films at high temperatures (1250°C) is observed to fill oxygen vacancies and increase grain size. The difference in the dielectric behavior for as-deposited and low temperature annealed BST films on MgO and BST films on LAO is observed and may be attributed to the differences in film stress. A further improvement in the dielectric behavior is observed by the addition of donor/acceptor dopants such as Mn. The data shows that ferroelectric thin films can be used to build tunable microwave circuits that offer significant performance advantages over devices made from conventional semiconducting materials.

Ion Channeling Studies of CdTe Films on GaAs

1988 ◽  
Vol 130 ◽  
Author(s):  
Barry Wilkens
Keyword(s):  
Thin Films ◽  
Lattice Mismatch ◽  
Ion Channeling ◽  
Model Based ◽  
Gaas Substrates ◽  
Cdte Films ◽  
Minimum Yield

AbstractThin films of [111] oriented CdTe have been MOCVD grown onto [111] GaAs substrates. When thicknesses exceed 1000Å the epitaxy is quite good (backscattering minimum yield of approximately 15%) in spite of a 14% lattice mismatch. A narrowing of the Cd angular scan suggests a displacement of some of the Cd atoms in the lattice. A model based on a Te vacancy is presented to describe the data.

Single-crystal and Nano-columnar Growth of Gadolinium-doped Ceria Thin Films on Oxide Substrates Studied Using Electron Microscopy

2003 ◽  
Vol 795 ◽  
Author(s):  
D. X. Huang ◽  
C. L. Chen ◽  
A. J. Jacobson
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Single Crystal ◽  
Grain Growth ◽  
Lattice Mismatch ◽  
Compressive Strain ◽  
Doped Ceria ◽  
Columnar Grain ◽  
Film Substrate ◽  
Gadolinium Doped Ceria

ABSTRACTGadolinium-doped ceria (GDC) thin films were grown by pulsed laser ablation on various oxide single crystal substrates including MgO, YSZ, LAO, NGO, and STO with different film-substrate lattice mismatch ratios. The film microstructures were characterized mainly by using electron microscopy. A clear influence of the filmsubstrate lattice mismatch on the film crystallinity has been observed. The GDC films usually exhibit columnar grain growth for a large range of film-substrate lattice mismatch ratios. A cube-on-cube growth of GDC film on MgO has been observed with a surprisingly high lattice mismatch ratio of 28%. The highest film crystallinity is obtained on the LAO substrates under a small compressive strain. This single-crystalline GDC film shows no columnar grain growth but presents a novel directionally-aligned precipitated Gd-rich nanoparticle system, which plays a specific role in relaxing various kinds of strain fields induced during the thin film growth to ensure the film crystallinity.

Measurement of small elastic strains in silicon using electron channeling patterns

1988 ◽  
Vol 3 (4) ◽  
pp. 710-713 ◽  
Author(s):  
J. A. Kozubowski ◽  
W. W. Gerberich ◽  
T. Stefanski
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Lower Limit ◽  
Elastic Strain ◽  
Silicon Single Crystal ◽  
Zero Order ◽  
Electron Channeling ◽  
Elastic Strains ◽  
Scanning Electron

A silicon single-crystal slab 0.15 mm in thickness was bent to produce small, nonuniform surface strains of the order of 0.2%. The electron channeling patterns were observed in a JSM 840 SEM (scanning electron microscope) at an accelerating voltage close to 25 kV. Proper choice of the triangles formed by intersecting channeling lines of zero-order and of higher-order Laue zones allows one to measure the changes in their dimensions caused by imposed strain. It was estimated that the lower limit of detectable elastic strain is close to 0.1%. The possibilities of using this method for estimation of the average elastic strains in thin epitaxial layers are discussed.

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