Nucleation and Heteroepitaxy of YBa2Cu3O7-δ thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 88-89
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Film Growth ◽  
Thin Foil ◽  
Substrate Material ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Bulk Single Crystal ◽  
Transmission Electron ◽  
Final Sample

The nucleation and heteroepitactic growth of YBa2Cu3O7−δ thin-films has been studied by transmission electron microscopy (TEM). The films were formed by pulsed-laser ablation and then observed in the TEM without further sample preparation. Direct observation of the early stages of film growth is possible due to the utilization of a new specimen-preparation technique. The films were deposited directly onto specially prepared electron-transparent substrates. The substrate material used in this study was single-crystal, (001)-oriented MgO. The thin-foil substrates were prepared from bulk single-crystal substrates in the following manner. Discs of 3mm diameter were cored, polished and dimpled to produce a final sample thickness of 10 - 20μm. The samples were ion milled to perforation using 5 kV Ar+ ions, then chemically cleaned. The cleaned foils were annealed in air at 1350°C for 10min. The annealing temperature is such that sufficient atomic mobility enables the formation of a series of steps on the surface.

Early Stages of Growth of BaTiO3 Thin-Films

1990 ◽  
Vol 200 ◽  
Author(s):  
M. Grant Norton ◽  
Gerald R. English ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Lattice Mismatch ◽  
Pulsed Laser ◽  
Surface Preparation ◽  
Thin Foil ◽  
Stages Of Growth ◽  
Early Stages ◽  
Transmission Electron ◽  
Film Nucleation

ABSTRACTBarium titanate (BaTiO3) is of interest for use in a number of thin-film applications in electronic and optoelectronic devices. For these devices the formation of epitactic films of the correct stoichiometry and phase is essential. The substrate is important during the early stages of growth in the establishment of epitaxy, factors such as lattice mismatch, surface preparation and crystallographic orientation can all affect film nucleation and growth. In this study thin-films of BaTiO3 have been formed using the pulsed-laser ablation technique. The early stages of film growth have been studied directly using transmission electron microscopy by examination of very thin films deposited onto specially prepared electron-transparent thin-foil substrates.

Epitaxial growth and magnetic behavior of NiFe2O4 thin films

1996 ◽  
Vol 11 (5) ◽  
pp. 1187-1198 ◽  
Author(s):  
S. Venzke ◽  
R. B. van Dover ◽  
Julia M. Phillips ◽  
E. M. Gyorgy ◽  
T. Siegrist ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Structural Changes ◽  
Amorphous Material ◽  
Magnetic Behavior ◽  
Bulk Single Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Channeling ◽  
Transmission Electron

Thin films of NiFe2O4 were deposited on SrTiO3 (001) and Y0.15Zr0.85O2 (yttria-stabilized zirconia) (001) and (011) substrates by 90°-off-axis sputtering. Ion channeling, x-ray diffraction, and transmission electron microscopy studies reveal that films grown at 600 °C consist of ∼300 Å diameter grains separated by thin regions of highly defective or amorphous material. The development of this microstructure is attributed to the presence of rotated or displaced crystallographic domains and is comparable to that observed in other materials grown on mismatched substrates (e.g., GaAs/Si or Ba2YCu3O7/MgO). Postdeposition annealing at 1000 °C yields films that are essentially single crystal. The magnetic properties of the films are strongly affected by the structural changes; unannealed films are not magnetically saturated even in an applied field of 55 kOe, while the annealed films have properties comparable to those of bulk, single crystal NiFe2O4. Homoepitaxial films grown at 400 °C also are essentially single crystal.

Observation of the early stages of heteroepitactic growth of BaTiO3 thin-films

1990 ◽  
Vol 5 (12) ◽  
pp. 2762-2765 ◽  
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Stoichiometric Composition ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Foil ◽  
Nucleation And Growth ◽  
Small Islands ◽  
Early Stages ◽  
Transmission Electron

Thin-films of barium titanate (BaTiO3) have been deposited onto single-crystal MgO substrates using pulsed-laser ablation. The early stages of film growth have been examined using transmission electron microscopy by deposition of very thin films onto specially prepared electron transparent thin-foil substrates. The films, which were crystalline as deposited and close to stoichiometric composition, were formed by the nucleation and growth of small islands.

Contrast from epitaxially sandwiched macromolecules

1978 ◽  
Vol 36 (2) ◽  
pp. 226-227
Author(s):  
M. Talianker ◽  
D.G. Brandon
Keyword(s):  
Gold Film ◽  
Lattice Defect ◽  
Gold Foil ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Resolution Limit ◽  
Transmission Electron ◽  
Crystal Lattice Defect ◽  
Void Effect ◽  
Lattice Resolution

A new specimen preparation technique for visualizing macromolecules by conventional transmission electron microscopy has been developed. In this technique the biopolymer-molecule is embedded in a thin monocrystalline gold foil. Such embedding can be performed in the following way: the biopolymer is deposited on an epitaxially-grown thin single-crystal gold film. The molecule is then occluded by further epitaxial growth. In such an epitaxial sandwich an occluded molecule is expected to behave as a crystal-lattice defect and give rise to contrast in the electron microscope.The resolution of the method should be limited only by the precision with which the epitaxially grown gold reflects the details of the molecular structure and, in favorable cases, can approach the lattice resolution limit.In order to estimate the strength of the contrast due to the void-effect arising from occlusion of the DNA-molecule in a gold crystal some calculations were performed.

Microstructural characterization of YBaCuO Films on LaAlO3 substrates

1989 ◽  
Vol 47 ◽  
pp. 180-181
Author(s):  
E. L. Hall ◽  
A. Mogro-Campero ◽  
N. Lewis ◽  
L. G. Turner
Keyword(s):  
Dielectric Constant ◽  
Single Crystal ◽  
Film Growth ◽  
Microstructural Characterization ◽  
Lattice Parameter ◽  
Film Plane ◽  
Substrate Material ◽  
High Loss ◽  
Amorphous Substrates ◽  
High Dielectric

There have been a large number of recent studies of the growth of Y-Ba-Cu-O thin films, and these studies have employed a variety of substrates and growth techniques. To date, the highest values of Tc and Jc have been found for films grown by sputtering or coevaporation on single-crystal SrTiO3 substrates, which produces a uniaxially-aligned film with the YBa2Cu3Ox c-axis normal to the film plane. Multilayer growth of films on the same substrate produces a triaxially-aligned film (regions of the film have their c-axis parallel to each of the three substrate <100> directions) with lower values of Jc. Growth of films on a variety of other polycrystalline or amorphous substrates produces randomly-oriented polycrystalline films with low Jc. Although single-crystal SrTiO3 thus produces the best results, this substrate material has a number of undesireable characteristics relative to electronic applications, including very high dielectric constant and a high loss tangent at microwave frequencies. Recently, Simon et al. have shown that LaAlO3 could be used as a substrate for YBaCuO film growth. This substrate is essentially a cubic perovskite with a lattice parameter of 0.3792nm (it has a slight rhombohedral distortion at room temperature) and this material exhibits much lower dielectric constant and microwave loss tangents than SrTiO3. It is also interesting from a film growth standpoint since it has a slightly smaller lattice parameter than YBa2Cu3Ox (a=0.382nm, b=c/3=0.389nm), while SrTiO3 is slightly larger (a=0.3905nm).

Transmission Electron Microscopy (TEM) Specimen Preparation Technique using Focused Ion Beam (FIB): Application to Material Characterization of Chemical Vapor Deposition of Tungsten (W) and Tungsten Silicides (WSix)

1997 ◽  
Author(s):  
K. Doong ◽  
J.-M. Fu ◽  
Y.-C. Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Chemical Vapor ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Transmission Electron

Abstract The specimen preparation technique using focused ion beam (FIB) to generate cross-sectional transmission electron microscopy (XTEM) samples of chemical vapor deposition (CVD) of Tungsten-plug (W-plug) and Tungsten Silicides (WSix) was studied. Using the combination method including two axes tilting[l], gas enhanced focused ion beam milling[2] and sacrificial metal coating on both sides of electron transmission membrane[3], it was possible to prepare a sample with minimal thickness (less than 1000 A) to get high spatial resolution in TEM observation. Based on this novel thinning technique, some applications such as XTEM observation of W-plug with different aspect ratio (I - 6), and the grain structure of CVD W-plug and CVD WSix were done. Also the problems and artifacts of XTEM sample preparation of high Z-factor material such as CVD W-plug and CVD WSix were given and the ways to avoid or minimize them were suggested.

scholarly journals Influence of Substrate Materials on Nucleation and Properties of Iridium Thin Films Grown by ALD

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Paul Schmitt ◽  
Vivek Beladiya ◽  
Nadja Felde ◽  
Pallabi Paul ◽  
Felix Otto ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Bulk Material ◽  
Atomic Layer ◽  
Substrate Material ◽  
Fused Silica ◽  
Silicon Wafers ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Influence Of Substrate

Ultra-thin metallic films are widely applied in optics and microelectronics. However, their properties differ significantly from the bulk material and depend on the substrate material. The nucleation, film growth, and layer properties of atomic layer deposited (ALD) iridium thin films are evaluated on silicon wafers, BK7, fused silica, SiO2, TiO2, Ta2O5, Al2O3, HfO2, Ru, Cr, Mo, and graphite to understand the influence of various substrate materials. This comprehensive study was carried out using scanning electron and atomic force microscopy, X-ray reflectivity and diffraction, four-point probe resistivity and contact angle measurements, tape tests, and Auger electron spectroscopy. Within few ALD cycles, iridium islands occur on all substrates. Nevertheless, their size, shape, and distribution depend on the substrate. Ultra-thin (almost) closed Ir layers grow on a Ta2O5 seed layer after 100 cycles corresponding to about 5 nm film thickness. In contrast, the growth on Al2O3 and HfO2 is strongly inhibited. The iridium growth on silicon wafers is overall linear. On BK7, fused silica, SiO2, TiO2, Ta2O5, Ru, Cr, and graphite, three different growth regimes are distinguishable. The surface free energy of the substrates correlates with their iridium nucleation delay. Our work, therefore, demonstrates that substrates can significantly tailor the properties of ultra-thin films.

scholarly journals Donald William Pashley. 21 April 1927 — 16 May 2009

2010 ◽  
Vol 56 ◽  
pp. 317-340 ◽  
Author(s):  
Bruce A. Joyce ◽  
Michael J. Stowell
Keyword(s):  
Thin Films ◽  
Electron Microscope ◽  
Electron Diffraction ◽  
Film Growth ◽  
Epitaxial Thin Films ◽  
Disorder Effects ◽  
Transmission Electron ◽  
Innovative Materials ◽  
Low Dimensional

Donald William (Don) Pashley was one of the most innovative materials scientists of his generation. He was distinguished for his electron diffraction and transmission electron microscope studies of epitaxial thin films, especially for in situ investigations, work that contributed enormously to our understanding of film growth processes. He pioneered the use of moiré patterns to reveal dislocations and other defects. He also made important contributions to long-range disorder effects on semiconductor surfaces and to the structure of low-dimensional semiconductor systems.

Microstresses in Molybdenum Nitride Thin Films Deposited by Reactive DC Magnetron Sputtering

2005 ◽  
Vol 490-491 ◽  
pp. 589-594 ◽  
Author(s):  
Yao Gen Shen
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Film Growth ◽  
Nitrogen Addition ◽  
Molybdenum Nitride ◽  
Dc Magnetron Sputtering ◽  
Cross Sectional ◽  
Dense Microstructure ◽  
Transmission Electron ◽  
Complete Relaxation

Thin films of molybdenum nitride (MoNx with 0≤x≤0.35) were deposited on Si(100) at room temperature using reactive DC magnetron sputtering. The residual stress of films was measured as a function of sputtering pressure, nitrogen incorporation, and annealing temperature by wafer curvature-based technique. It was found that the stress of the films was strongly related to their microstructure, which depended mainly on the incorporation of nitrogen in the films. The film stresses without nitrogen addition strongly depended on the argon pressure and changed from highly compressive to highly tensile in a relatively narrow pressure range of 0.8-1.6 Pa. For pressures exceeding ~5.3 Pa, the stress in the film was nearly zero. Cross-sectional transmission electron microscopy indicated that the compressively stressed films contained a dense microstructure without any columns, while the films having tensile stress had a very columnar microstructure. High sputtering-gas pressure conditions yielded dendritic-like film growth, resulting in complete relaxation of the residual tensile stresses. It was also found that the asdeposited film was poorly ordered in structure. When the film was heated at ~775 K, crystallization occurred and the stress of the film drastically changed from –0.75 to 1.65 GPa. The stress development mechanism may be due to volumetric shrinkage of the film during crystallization.

The Use of Energy Dispersive Diffractometry to Measure the Thickness of Metal and Glass Thin Films

1981 ◽  
Vol 25 ◽  
pp. 365-371
Author(s):  
Glen A. Stone
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Single Crystal Silicon ◽  
Substrate Material ◽  
Silicon Wafers ◽  
Energy Dispersive ◽  
Crystal Silicon ◽  
X Ray ◽  
Phosphosilicate Glass ◽  
Film Substrate

This paper presents a new method to measure the thickness of very thin films on a substrate material using energy dispersive x-ray diffractometry. The method can be used for many film-substrate combinations. The specific application to be presented is the measurement of phosphosilicate glass films on single crystal silicon wafers.

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