Transmission Electron Microscopy Studies of Aluminum Oxidation

Author(s):  
J.Y. Lee

In the oxidation of metals and alloys, microstructural features at the atomic level play an important role in the nucleation and growth of the oxide, but little is known about the atomic mechanisms of high temperature oxidation. The present paper describes current progress on crystallographic aspects of aluminum oxidation. The 99.999% pure, polycrystalline aluminum was chemically polished and oxidized in 1 atm air at either 550°C or 600°C for times from 0.5 hr to 4 weeks. Cross-sectional specimens were prepared by forming a sandwich with epoxy, followed by mechanical polishing and then argon ion milling. High resolution images were recorded in a <110>oxide zone-axis orientation with a JE0L JEM 200CX microscope operated at 200 keV.

Author(s):  
Geun-Hong Kim ◽  
Chang-Hwan Chun

Commercial diamond coated WC-Co cutting tool has been investigated by transmission electron microscope (TEM) to understand the nucleation and growth of diamond on WC substrate. Cross-sectional specimens have been prepared by mechanical polishing followed by ion milling. TEM observations have been performed using analytical TEM, JEM 4000FX (JEOL Ltd.).The surface of the coated diamond is composed of grains of 2 - 5 μm in diameter. Each main grain is formed by columnar subgrains of 10 - 50 nm in diameter with similar orientations. Cobalt, a binder in cemented carbide, within 5 μm in depth from the carbide surface has been found to be removed to increase the adhesion of diamond.One of diamond subgrains, which has been grown large in [001] orientation on WC grains is shown in Fig. 1. High density of twins are found on (111) plane starting from WC grain boundaries. It is thought that the interfacial stress between diamond layer and WC grains is accommodated by these twins.


1987 ◽  
Vol 115 ◽  
Author(s):  
D. Bahnck ◽  
J. L. Batstone ◽  
Julia M. Phillips

ABSTRACTTechniques for the preparation of specimens for Transmission Electron Microscopy analysis are described. Cross-sectional specimens of insulator/semiconductor heterostructures have been successfully prepared. The problem of differential thinning rates and interface amorphization during argon ion-milling have been overcome using low argon ion accelerating voltages and shallow angles of incidence. Techniques for preparation of plan view specimens include the preparation of silicon substrates for in-situ crystal growth in an ultrahigh vacuum Transmission Electron Microscope.


Author(s):  
Julia T. Luck ◽  
C. W. Boggs ◽  
S. J. Pennycook

The use of cross-sectional Transmission Electron Microscopy (TEM) has become invaluable for the characterization of the near-surface regions of semiconductors following ion-implantation and/or transient thermal processing. A fast and reliable technique is required which produces a large thin region while preserving the original sample surface. New analytical techniques, particularly the direct imaging of dopant distributions, also require good thickness uniformity. Two methods of ion milling are commonly used, and are compared below. The older method involves milling with a single gun from each side in turn, whereas a newer method uses two guns to mill from both sides simultaneously.


Author(s):  
F. Shaapur

Non-uniform ion-thinning of heterogenous material structures has constituted a fundamental difficulty in preparation of specimens for transmission electron microscopy (TEM). A variety of corrective procedures have been developed and reported for reducing or eliminating the effect. Some of these techniques are applicable to any non-homogeneous material system and others only to unidirectionalfy heterogeneous samples. Recently, a procedure of the latter type has been developed which is mainly based on a new motion profile for the specimen rotation during ion-milling. This motion profile consists of reversing partial revolutions (RPR) within a fixed sector which is centered around a direction perpendicular to the specimen heterogeneity axis. The ion-milling results obtained through this technique, as studied on a number of thin film cross-sectional TEM (XTEM) specimens, have proved to be superior to those produced via other procedures.XTEM specimens from integrated circuit (IC) devices essentially form a complex unidirectional nonhomogeneous structure. The presence of a variety of mostly lateral features at different levels along the substrate surface (consisting of conductors, semiconductors, and insulators) generally cause non-uniform results if ion-thinned conventionally.


Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.


2018 ◽  
Author(s):  
C.S. Bonifacio ◽  
P. Nowakowski ◽  
M.J. Campin ◽  
M.L. Ray ◽  
P.E. Fischione

Abstract Transmission electron microscopy (TEM) specimens are typically prepared using the focused ion beam (FIB) due to its site specificity, and fast and accurate thinning capabilities. However, TEM and high-resolution TEM (HRTEM) analysis may be limited due to the resulting FIB-induced artifacts. This work identifies FIB artifacts and presents the use of argon ion milling for the removal of FIB-induced damage for reproducible TEM specimen preparation of current and future fin field effect transistor (FinFET) technologies. Subsequently, high-quality and electron-transparent TEM specimens of less than 20 nm are obtained.


1992 ◽  
Vol 7 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Z.G. Li ◽  
P.F. Carcia ◽  
P.C. Donohue

The microstructure of LaB6-base thick film resistors was investigated by cross-sectional transmission electron microscopy. The specimens were prepared by a technique that polished them to a thin wedge, thus avoiding ion-milling and permitting imaging over a distance of tens of microns. The resistor microstructure contained a finely divided electrically conductive phase of TaB2 and nonconducting crystals of CaTa4O11, formed during high temperature processing of glass and LaB6 ingredients of the thick film ink. Using higher surface area ingredients virtually suppressed the formation of CaTa4O11 crystals, and the microstructure became more uniform. Resistors made with higher surface area intermediates also had better voltage withstanding properties.


1989 ◽  
Vol 147 ◽  
Author(s):  
K. S. Jones ◽  
J. Yu ◽  
P. D. Lowen ◽  
D. Kisker

AbstractTransmission electron diffraction patterns of cross-sectional TEM samples of OMVPE ZnSe on GaAs indicate the existence of the hexagonal wurtzite phase in the epitaxial layers. The orientation relationship is (0002)//(111); (1120)//(220). Etching studies indicate the phase is internal not ion milling induced. The average wurtzite particle size is 80Å-120Å. Because of interplanar spacing matches it is easily overlooked. Electrical property measurements show a high resistivity (1010ω/square) which drops by four orders of magnitude upon rapid thermal annealing between 700°C and 900 °C for 3 sec. Implantation of Li and N have little effect on the electrical transport properties. The Li is shown to have a high diffusivity, a solid solubility of ≈1016/cm3 at 800°C and getters to the ZnSeA/aAs interface.


1998 ◽  
Vol 4 (S2) ◽  
pp. 720-721
Author(s):  
T. Chen ◽  
J.M. Hampikian ◽  
N.N. Thadhani ◽  
Z.L. Wang

NiAl is an important high temperature structural material, with a high melting point (1640°C), low density and excellent high temperature oxidation resistance. The room temperature ductility of NiAl may potentially be improved with the use of nanocrystalline grain size. However, a key question concerning the application of nanostructured NiAl is about its structural stability at high temperature. The current study is thus focused on the investigation of the structural stability of nanocrystalline NiAl using in-situ transmission electron microscopy (TEM) and differential thermal analysis (DTA).Nanocrystalline B2-NiAl was prepared by ball milling (24 hrs) from elemental Ni and Al powders. Subsequent consolidation into bulk form was performed using dynamic consolidation employing a 3-capsule plate-impact fixture at approximately 400 m/s [1-3]. Powder nanocrystalline NiAl was dispersed on a holey carbon film for TEM observation. TEM specimens of shock compacted bulk NiAl nanocrystals were prepared by cutting, polishing, dimpling and ion milling.


2011 ◽  
Vol 5 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Maja Popovic ◽  
Mirjana Novakovic ◽  
Zlatko Rakocevic ◽  
Natasa Bibic

In this work, the effects of 120 keV Ar+ ion implantation on the structural properties of TiN thin films were investigated. TiN layers were deposited by d.c. reactive sputtering on Si(100) wafers at room temperature or at 150?C. The thickness of TiN layers was ~240 nm. After deposition the samples were irradiated with 120 keV argon ions to the fluencies of 1?1015 and 1?1016 ions/cm2. Structural characterization was performed with Rutherford backscattering spectroscopy (RBS), cross-sectional transmission electron microscopy (XTEM), grazing angle X-ray diffraction (XRD) and atomic force microscopy (AFM). It was found that the argon ion irradiation induced the changes in the lattice constant, mean grain size, micro-strain and surface morphology of the TiN layers. The observed micro-structural changes are due to the formation of the high density damage region in the TiN thin film structure.


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