Microstructure of YBa2Cu3O7-δ/Ag Bilayers Grown In Situ on Step-Edge SrTiO3 Substrates

1995 ◽  
Vol 401 ◽  
Author(s):  
Z. H. Gong ◽  
J. K. Grepstad ◽  
S. Andersen ◽  
A. Bardal
Keyword(s):  
Film Growth ◽  
Ybco Film ◽  
Amorphous Material ◽  
Interfacial Microstructure ◽  
High Density ◽  
Step Edge ◽  
Transmission Electron ◽  
Lattice Images ◽  
Sputter Deposited

AbstractThe microstructure of YBa2Cu3O7-δ(YBCO)/Ag bilayers sputter deposited in situ on step-edge SrTiO3 (STO) substrates, was carefully examined by transmission electron microscopy (TEM). Considerable variation in the YBCO film growth morphology is found near steps, including film protrusions beyond the step edges and film growth on slopes. Lattice images recorded near steps unveil a high density of crystalline defects in the film. An increased density of defects is also found near the substrate interface for film grown on etched STO surface. However, these defects are confined to the interface region and do not propagate beyond the scale of the STO surface roughness. Comparison of TEM lattice images of YBCO(100)/Ag and YBCO(001)/Ag junctions from the same specimen unveils a distinct difference in the interfacial microstructure of those two junctions. Whereas the former exhibits a sharp crystalline interface, the latter typically features a thin ( ∼ 20 Å ) interfacial layer of amorphous material. The YBCO film morphology and the high density of defects in the step edge region uncovered in this study suggest that manufacture of reproducible and uniform YBCO/Ag (Au)/YBCO (SNS) Josephson junctions using the step-edge technique, will prove a difficult task.

Modifications of a JEOL 2000EX TEM for insSitu surface studies

1993 ◽  
Vol 51 ◽  
pp. 640-641
Author(s):  
Michael T. Marshall ◽  
Xianghong Tong ◽  
J. Murray Gibson
Keyword(s):  
Electron Diffraction ◽  
Surface Science ◽  
Film Growth ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Transmission Electron ◽  
Fundamental Insight

We have modified a JEOL 2000EX Transmission Electron Microscope (TEM) to allow in-situ ultra-high vacuum (UHV) surface science experiments as well as transmission electron diffraction and imaging. Our goal is to support research in the areas of in-situ film growth, oxidation, and etching on semiconducter surfaces and, hence, gain fundamental insight of the structural components involved with these processes. The large volume chamber needed for such experiments limits the resolution to about 30 Å, primarily due to electron optics. Figure 1 shows the standard JEOL 2000EX TEM. The UHV chamber in figure 2 replaces the specimen area of the TEM, as shown in figure 3. The chamber is outfitted with Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), Residual Gas Analyzer (RGA), gas dosing, and evaporation sources. Reflection Electron Microscopy (REM) is also possible. This instrument is referred to as SHEBA (Surface High-energy Electron Beam Apparatus).The UHV chamber measures 800 mm in diameter and 400 mm in height. JEOL provided adapter flanges for the column.

Crystallization of Amorphous Silicon-Aluminum thin Films: IN-SITU Observation and Thermal Analysis.

1991 ◽  
Vol 237 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair
Keyword(s):  
Activation Energy ◽  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
In Situ Observation ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Higher Temperature ◽  
Sputter Deposited

ABSTRACTThe crystallization of sputter-deposited Si/Al amorphous alloys was examined by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). In-situ high-resolution TEM reveals the existence of an Al layer between the amorphous matrix and the growing crystalline phase. The activation energy for the growth is about 1.2eV, roughly corresponding to the activation energy of Si diffusion in Al. These two observations support the view that a crystallization mechanism, in which an Al buffer layer provides the shortest reaction path, is responsible for the reaction. The product microstructure exhibits secondary crystallization at a higher temperature.

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.

Thin Film Ag/YBCO Multistructures for Metal Contact Applications

1992 ◽  
Vol 275 ◽  
Author(s):  
M. Powers ◽  
R. Gronsky ◽  
J. Washburn
Keyword(s):  
Thin Film ◽  
Single Crystal ◽  
Ybco Film ◽  
Electrical Contact ◽  
Ceramic Substrate ◽  
Metal Contact ◽  
Intimate Contact ◽  
Sputter Deposited ◽  
Maximum Contact

ABSTRACTA technique is presented where Ag is initially sputter deposited on a single crystal ceramic substrate followed by in situ deposition of YBa2Cu3O7δ The resulting microstructure shows Ag islands amidst a c-axis oriented YBCO film, apparently with intimate contact between the YBCO and substrate. This morphology appears ideal for electrical contact to the {hko} surfaces of the superconductor with current carrying CuO planes in maximum contact with the Ag.

YBCO film growth on ultrathin Ag layers

1994 ◽  
Vol 9 (11) ◽  
pp. 2761-2763 ◽  
Author(s):  
C. Zhong ◽  
S.T. Ruggiero ◽  
R. Fletcher ◽  
E. Moser
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Film Growth ◽  
Ybco Film ◽  
Critical Currents ◽  
Complete Coverage ◽  
Force Microscopy ◽  
Atomic Force ◽  
Sputter Deposited ◽  
Marked Tendency

We discuss our results on the growth of YBCO thin films on ultrathin (1-10 nm) Ag underlayers. Substrates were LaAlO3. YBCO was sputter deposited and Ag thermally evaporated. It was observed that Tc remained relatively unaffected by the Ag underlayers, ranging from 86-88 K. Critical currents were found to be consistent with YBCO grown on bulk Ag when the Ag underlayer film reached complete coverage (∼9 nm). Films grown on Ag showed a marked tendency for microcrystalline growth on the basis of atomic-force microscopy (AFM) results.

HRTEM Analysis of Magnetron Sputtered Ni4Al Thin Films

2015 ◽  
Vol 761 ◽  
pp. 504-509
Author(s):  
T. Joseph Sahaya Anand ◽  
Mohd Asyadi Azam ◽  
Sivaraos ◽  
Zolkepli Buang ◽  
Rajes K.M. Rajan ◽  
...  
Keyword(s):  
Isothermal Annealing ◽  
Vacuum Annealing ◽  
Nanocrystalline Structure ◽  
Al Alloy ◽  
Transmission Electron ◽  
Annealing Heat Treatment ◽  
Magnetron Sputter ◽  
Sputter Deposited ◽  
Grain Coalescence

The nanostructural characteristics of direct-current magnetron sputter-deposited Ni4Al alloy films were studied during in situ isothermal annealing in a transmission electron microscope (TEM). An expansion of the lattice by nearly 5% was observed for the synthesized films in their low-thickness and as-deposited state. The lattice size approaches the bulk value when the film thickness increases or after vacuum annealing heat-treatment. The Ni4Al films have a nanocrystalline structure in which the ordered L12 phase appears upon annealing at above 500°C. A grain coalescence trend was found for the Ni4Al films during the in situ annealing above 500°C. This can be the main reason for the abnormal grain growth of these films at these high temperatures.

Surface study by UHV electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 458-459
Author(s):  
K. Yagi ◽  
K. Takayanagi ◽  
K. Kobayashi ◽  
N. Osakabe ◽  
Y. Tanishiro ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Film Growth ◽  
Atomic Layer ◽  
Chemical Compositions ◽  
Surface Phenomena ◽  
Transmission Electron ◽  
In Situ Deposition ◽  
Complementary Role ◽  
Atomically Flat

Recent advances of UHV techniques, LEED, RHEED and AES, arose a surge of interest on the surface of solids. These techniques reveal structures and chemical compositions at the mono-atomic or mono-molecular level. All of them, however, are devoid of detailed topographic informations, although some efforts to introduce the scanning techniques have been done[l]. Transmission electron microscopy of high resolution should play a complementary role to these techniques. No attempt, however, has been done previously to use it to such a purpose. This was because it was difficult to get and keep clean surfaces in the poor vacuum at 1x10-5 Torr level of the conventional electron microscope.The present paper reports observations of surface phenomena of one or two atomic layer level using a UHV JEM 100B electron microscope (10-8 -10-10Torr), recently developed for insitu thin film growth studies[2]. Atomically flat (111) surfaces of Ag, Pd, Au and Cu were prepared by in- situ deposition at 150-350°C on M0S2, graphite and MgO. Air Cleaved thin films of MoS2 and graphite were preheated to 800°C to get clean surfaces[3].

The Effect of Deposition and Annealing Conditions on the Microstructure of Al-Cu and Al-Cu-Si Thin Films

1991 ◽  
Vol 229 ◽  
Author(s):  
M. Park ◽  
S. J. Krause ◽  
S. R. Wilson
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Phase Region ◽  
Annealed Condition ◽  
Two Phase ◽  
Annealing Conditions ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Cu Thin Film

AbstractThe effect of deposition temperature and the addition of Si to sputter deposited Al-Cu thin-film microstructure was studied with transmission electron microscopy. Films were studied in the as-deposited and annealed condition. The effects of thermal treatment were studied with in-situ hot stage microscopy. Al2Cu (θ) precipitated at the grain boundaries and the sublayer interface. At higher deposition temperatures, with alloy composition in single phase region (Al-1.5 wt.%Cu), Al2Cu precipitated during cooldown. At lower temperatures, in the two phase Al-0 region, Al2Cu precipitated during deposition. The addition of Si caused formation of Si precipitates and retarded Al2Cu precipitation during deposition or cooldown.

A Model for Calculating Substrate Curvature During Coalescence of PT Islands on an Amorphous Substrate

1999 ◽  
Vol 578 ◽  
Author(s):  
M. A. Phillips ◽  
V. Ramaswamy ◽  
B. M. Clemens ◽  
W. D. Nix
Keyword(s):  
Film Growth ◽  
Film Stress ◽  
Plan View ◽  
Amorphous Substrates ◽  
Areal Fraction ◽  
Island Coalescence ◽  
Sputter Deposited ◽  
Evolution Of Microstructure ◽  
Pt Films

AbstractPrevious work using in-situ curvature measurement has shown a correlation between stress and microstructure during the early stages of thin film growth. The model presented here can be used to predict the curvature change of the substrate during part of this growth process. Curvature, and thus film stress, is measured in-situ during growth of sputter-deposited Pt on amorphous substrates. The average film stress is observed to be slightly compressive initially, followed by a change towards a tensile maximum, after which the stress becomes compressive again. Plan view TEM micrographs of Pt films of thicknesses up to 35 Å show the evolution of microstructure from isolated islands to a coalesced film. This evidence suggests that the tensile regime is due to island coalescence. The model calculates the curvature induced in a substrate during the tensile excursion associated with island coalescence, where discontinuous islands are modeled as a series of cracks in an otherwise continuous film. Quantitative measurements of island size and areal fraction covered are extracted from the TEM micrographs and used to predict the curvature during coalescence. The predicted stresses are shown to compare favorably with the measured stresses.

Amorphisation and Recrystallisation of Nanometre Sized Zones in Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 145-150 ◽  
Author(s):  
P.D. Edmondson ◽  
S.E. Donnelly ◽  
R.C. Birtcher
Keyword(s):  
Electron Microscopy ◽  
Amorphous Material ◽  
Heavy Ion ◽  
Initial Size ◽  
Transmission Electron ◽  
Wide Range ◽  
Ion Impact ◽  
Amorphous Zone ◽  
The Individual

In this paper we present a detailed study in which the formation, by heavy ion impact, and thermal recrystallisation of individual amorphous zones have been studied using in-situ transmission electron microscopy. In agreement with previous work, we observe a reduction in the total volume of amorphous material contained within the amorphous zones following thermal annealing over a wide range of temperatures. When the evolution of the individual amorphous zones is followed, those with similar starting sizes are observed to recrystallise over a range of temperatures from 70 °C to 500 °C. The temperature at which an amorphous zone fully recrystallises does not appear to be correlated with initial size. In addition, zones are occasionally observed to increase in size temporarily on some isochronal annealing steps. Furthermore, observations during a ramp anneal show that many zones recrystallise in a stepwise manner separated by periods of stability. These phenomenon are discussed in terms of the I-V pair.

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