Interface Structure and Layer Synthesis Modes in Mesotaxial Si/CoSi2/Si Structures

1990 ◽  
Vol 183 ◽  
Author(s):  
R. Hull ◽  
Y. F. Hsieh ◽  
K. T. Short ◽  
A. E. White ◽  
D. Cherns

AbstractWe report observations of interfacial structure and consequences for layer synthesis modes in mesotaxial Si/CoSi2/Si structures, as deduced from high resolution transmission electron microscopy (HRTEM). It is argued that relative crystal misalignments arising from the lattice parameter mismatch between the Si and CoSi2 may render classic rigid shift measurements of interfacial structure inaccurate. An alternative method for determining interfacial structure at threedimensional precipitates by analyzing crystal stacking sequences is demonstrated.

1994 ◽  
Vol 357 ◽  
Author(s):  
A. J. Pedraza ◽  
Siqi Cao ◽  
L. F. Allard ◽  
D. H. Lowndes

AbstractA near-surface thin layer is melted when single crystal alumina (sapphire) is pulsed laserirradiated in an Ar-4%H2 atmosphere. γ-alumina grows epitaxially from the (0001) face of axalumina (sapphire) during the rapid solidification of this layer that occurs once the laser pulse is over. Cross sectional high resolution transmission electron microscopy (HRTEM) reveals that the interface between unmelted sapphire and γ-alumina is atomistically flat with steps of one to a few close-packed oxygen layers; however, pronounced lattice distortions exist in the resolidified γ-alumina. HRTEM also is used to study the metal-ceramic interface of a copper film deposited on a laser-irradiated alumina substrate. The observed changes of the interfacial structure relative to that of unexposed substrates are correlated with the strong enhancement of film-substrate bonding promoted by laser irradiation. HRTEM shows that a thin amorphous film is produced after irradiation of 99.6% polycrystalline alumina. Formation of a diffuse interface and atomic rearrangements that can take place in metastable phases contribute to enhance the bonding strength of copper to laser-irradiated alumina.


1993 ◽  
Vol 32 (Part 1, No. 6A) ◽  
pp. 2824-2831 ◽  
Author(s):  
Nobuyuki Ikarashi ◽  
Masaaki Tanaka ◽  
Toshio Baba ◽  
Hiroyuki Sakaki ◽  
Koichi Ishida

2009 ◽  
Vol 24 (1) ◽  
pp. 192-197 ◽  
Author(s):  
G.M. Cheng ◽  
Y.X. Tian ◽  
L.L. He

The orientation relationship (OR) and the interfacial structure between Nb solid solution (Nbss) precipitates and α-Nb5Si3 intermetallics have been investigated by transmission electron microscopy (TEM). The OR between Nbss and α-Nb5Si3 was determined by selected-area electron diffraction analyses as (222)Nb//(002)α and . High-resolution TEM images of the Nbss/α-Nb5Si3 interface were presented. Steps existed at the interface that acted as centers of stress concentration and released the distortion of lattices to decrease the interfacial energy. In addition, the interfacial models were proposed based on the observed OR to describe the atomic matching of the interface. The distribution of alloying elements at the Nbss/α-Nb5Si3 interface has also been investigated, and Hf was enriched at the interface to strengthen the grain boundary.


2008 ◽  
Vol 14 (5) ◽  
pp. 433-438 ◽  
Author(s):  
Daniel Biggemann ◽  
Marcelo H. Prado da Silva ◽  
Alexandre M. Rossi ◽  
Antonio J. Ramirez

AbstractCrystalline properties of synthetic nanostructured hydroxyapatite (n-HA) were studied using high-resolution transmission electron microscopy. The focal-series-restoration technique, obtaining exit-plane wavefunction and spherical aberration-corrected images, was successfully applied for the first time in this electron-beam-susceptible material. Multislice simulations and energy dispersive X-ray spectroscopy were also employed to determine unequivocally that n-HA particles of different size preserve stoichiometric HA-like crystal structure. n-HA particles with sizes of twice the HA lattice parameter were found. These results can be used to optimize n-HA sinterization parameters to improve bioactivity.


Author(s):  
J. M. Howe

In situ hot-stage high-resolution transmission electron microscopy (HRTEM) provides unique capabilities for quantifying the dynamics of interfaces at the atomic level. Such information complements detailed static observations and calculations of interfacial structure, and is essential for understanding interface theory and solid-state phase transformations. This paper provides a brief description of particular requirements for performing in situ hot-stage HRTEM and illustrates the use of this technique to obtain quantitative data on the atomic mechanisms and kinetics of interface motion during precipitation of {111} θ phase in an Al-Cu-Mg-Ag alloy.The specimen and microscope requirements for in situ hot-stage HRTEM are not much different from those of static HRTEM, except that one must have a heating holder and equipment for recording and analyzing dynamic images. At present, most HRTEMs are equipped with a TV-rate camera, possibly combined with a charge-coupled device camera. An inexpensive way to record in situ HRTEM images is to send the output from the TV-rate camera directly into a standard VHS format videocassette recorder (VCR).


1986 ◽  
Vol 77 ◽  
Author(s):  
R. Hull ◽  
K. W. Carey ◽  
G. A. Reid

ABSTRACTWe define the Interface between two dissimilar materials by two functions, g(z) and f(x,y), representing the diffuseness along the interface normal and the distribution of interface non-planarities respectively. We show how these functions may be measured for the case of epitaxial interfaces between dissimilar crystals by quantitative analysis of lattice structure images obtained by high resolution transmission electron microscopy. Experimental examples are drawn from the GeSi/Si, InGaAs/InAlAs and InGaAs/InP systems. Correlations between interface structure and optical and electronic properties of these systems are discussed.


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