scholarly journals Ultra-Thin Films with Metastable Structures in Metallic Superlattice Films.

1996 ◽  
Vol 38 (6) ◽  
pp. 407-413
Author(s):  
Noriaki NAKAYAMA
Keyword(s):  
Thin Films ◽  
Metastable Structures

Interface Stabilization of W-N Coatings by Chromium Alloying

1991 ◽  
Vol 237 ◽  
Author(s):  
O. Knotek ◽  
F. Löftier ◽  
A. Barimani
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Vapour Deposition ◽  
Reactive Sputtering ◽  
Interface Layer ◽  
Stable Configuration ◽  
Tungsten Nitride ◽  
Physical Vapour Deposition ◽  
Metastable Structures ◽  
Equilibrium Phases

ABSTRACTNew metastable materials can be deposited using low temperature physical vapour deposition (PVD) techniques. During reactive sputtering, the atoms condensing in an intermixed state attempt to achieve a stable configuration. Due to low mobility of the adatoms, equilibrium phases cannot form and metastable structures are observed. Reactive sputtering can be used to deposit films with different stoichiometries and structures in the W-N system. The metastable phases α-W. β-W. W2N and WN1−x are obtained. All coatings are, however, thermally unstable. At temperatures above 570 °C. all phases are transformed into the a-W modification. By alloying chromium to the coatings in the W-N system, it is possible to stabilize all tungsten and tungsten nitride modifications as well as the interface layer between the substrate and the thin films.

Metastable Structures in Al Thin Films Before the Onset of Corrosion Pitting as Observed using Liquid Cell Transmission Electron Microscopy

2014 ◽  
Vol 20 (2) ◽  
pp. 462-468 ◽  
Author(s):  
See Wee Chee ◽  
David J. Duquette ◽  
Frances M. Ross ◽  
Robert Hull
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Sample Surface ◽  
Flow Cell ◽  
Transmission Electron ◽  
Metastable Structures ◽  
Liquid Cell ◽  
Corrosion Pitting ◽  
Microstructure Of The Material

AbstractOne of the fundamental challenges in understanding the early stages of corrosion pitting in metals protected with an oxide film is that there are relatively few techniques that can probe microstructure with sufficient resolution while maintaining a wet environment. Here, we demonstrate that microstructural changes in Al thin films caused by aqueous NaCl solutions of varying chloride concentrations can be directly observed using a liquid flow cell enclosed within a transmission electron microscope (TEM) holder. In the absence of chloride, Al thin films did not exhibit significant corrosion when immersed in de-ionized water for 2 days. However, introducing 0.01 M NaCl solutions led to extensive random formation of blisters over the sample surface, while 0.1 M NaCl solutions formed anomalous structures that were larger than the typical grain size. Immersion in 1.0 M NaCl solutions led to fractal corrosion consistent with previously reported studies of Al thin films using optical microscopy. These results show the potential of in situ liquid cell electron microscopy for probing the processes that take place before the onset of pitting and for correlating pit locations with the underlying microstructure of the material.

Metastable structures in Au-Si thin films

1981 ◽  
Vol 81 (3) ◽  
pp. 213-223 ◽  
Author(s):  
Neelkanth G. Dhere ◽  
Claudio De A. Loural
Keyword(s):  
Thin Films ◽  
Metastable Structures

The study of interfacial reactions of nickel thin films on GaAs

1983 ◽  
Vol 41 ◽  
pp. 156-157
Author(s):  
L.J. Chen ◽  
Y.F. Hsieh
Keyword(s):  
Thin Films ◽  
Integrated Circuits ◽  
Interfacial Reactions ◽  
Metal Contacts ◽  
Nickel Thin Films ◽  
Thin Foils ◽  
The Status ◽  
Si Doped ◽  
Electron Microscopes

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

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