Lattice Structure and Electrical Properties of Epitaxial Aluminum on GaAs

1982 ◽  
Vol 18 ◽  
Author(s):  
Fernando ◽  
A. Ponce ◽  
Stephen J. Eglash
Keyword(s):  
Electron Microscopy ◽  
Lattice Structure ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Barrier Heights ◽  
Transmission Electron ◽  
Current Voltage ◽  
Abrupt Interface ◽  
Crystallographic Planes ◽  
The Individual

The crystal structure of aluminum layers grown by molecular beam epitaxy (MBE) on GaAs(100) was studied using high resolution transmission electron microscopy. We obtained cross-sectional images with nearly atomic resolution of the lattice structure at Al-GaAs interfaces. GaAs epitaxial layers were grown at 585 °C and cooled in the ultrahigh vacuum MBE growth chamber prior to aluminum deposition. After the desired substrate temperature had been achieved, aluminum was immediately deposited onto arsenic-rich surfaces at a rate of 1000 Å h−1.Aluminum layers deposited onto substrates at 80 °C exhibit an Al(110)/GaAs(100) epitaxial relationship along an abrupt interface. In some regions of the interface we observed isolated arsenic crystallites which were epitaxial with the GaAs substrate. The current-voltage (I-V) and capacitance-voltage (C–V) characteristics of this material are well behaved. Barrier heights of 0.79 eV and ideality factors of 1.04 were determined from room temperature I–V measurements.For aluminum deposited onto GaAs substrates at 400 °C, evidence of twodimensional nucleation and growth was observed. The resulting pyramid-shaped aluminum crystallites had facets along crystallographic planes. Two epitaxial relationships were observed: Al(100)/GaAs(100) and Al(110)/GaAs(100). We observed 12 Å steps along the Al(100)–GaAs(100) interface. C–V and scanning electron microscopy measurements indicate that the individual aluminum crystallites are electrically and physically separated.

Direct Correlation of Transport Properties and Microstructure In Y1Ba2Cu3O7-x Thin Film Grain Boundaries

1994 ◽  
Vol 357 ◽  
Author(s):  
B. V. Vuchic ◽  
K. L. Merkle ◽  
D. B. Buchholz ◽  
R. P. H. Chang ◽  
L. D. Marks
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Grain Boundaries ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Current Voltage ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
The Individual

AbstractIndividual 45° [001] tilt grain boundaries in Y1Ba2Cu3O7-x thin films grown on biepitaxial substrates were studied. The thin films were grown using both pulsed organometallic beam epitaxy (POMBE) and laser ablation. Transport characteristics of the individual grain boundaries were measured including resistance - temperature (R-T) and current - voltage (I-V) dependencies with and without an applied magnetic field. In order to elucidate possible structural origins of the differences in transport behavior, the same grain boundaries which were electrically characterized were subsequently thinned for electron-microscopy analysis. Transmission-electron-microscopy and high-resolution-electron-microscopy were used to structurally characterize the grain boundaries. The macroscopic and microscopic structures of two boundaries, a nominally resistive and a superconducting grain boundary, are compared.

Dependency of Nonvolatile Memory Behavior on Curing Temperature for Au Nanocrystals Embedded in PVK

2006 ◽  
Vol 965 ◽  
Author(s):  
Beyong-il Han ◽  
Chang-Kyu Lee ◽  
Jong-Sung Kwon ◽  
In-Chul Na ◽  
Jea-gun Park ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nonvolatile Memory ◽  
Curing Temperature ◽  
Cross Sectional ◽  
Measured Current ◽  
Transmission Electron ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Nano Crystal

ABSTRACTA bistable effects of Au nano-crystals embedded in poly(N-vinylcarbazole) (PVK) were observed. Subsequently we investigated dependency of the nonvolatile memory behavior on curing temperature for the Au nano-crystals embedded in the PVK. For the study, in the devices of different curing temperatures we measured current-voltage characteristics for the devices and investigated the formation of the Au nano-crystals using cross sectional transmission electron microscopy (TEM). The nonvolatile memory behavior depends on the curing temperature, which is attributed to the suitable formation of the Au nano-crystal.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

Ion thinning of integrated circuit transverse specimens for transmission electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1426-1427
Author(s):  
F. Shaapur
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuit ◽  
Substrate Surface ◽  
Homogeneous Material ◽  
Material System ◽  
Ion Milling ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Motion Profile

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.

On the Faceting of Polar Ceramic Surfaces: Microscopy and Holography Studies of MGO(111) Surfaces

1996 ◽  
Vol 54 ◽  
pp. 366-367
Author(s):  
M. Gajdardziska-Josifovska ◽  
B. G. Frost ◽  
E. Völkl ◽  
L. F. Allard
Keyword(s):  
Electron Microscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electron Holography ◽  
Flat Surfaces ◽  
Transmission Electron ◽  
Excess Surface ◽  
Polar Surfaces ◽  
Salt Structure ◽  
Crystallographic Planes

Polar surfaces are those crystallographic faces of ionically bonded solids which, when bulk terminated, have excess surface charge and a non-zero dipole moment perpendicular to the surface. In the case of crystals with a rock salt structure, {111} faces are the exemplary polar surfaces. It is commonly believed that such polar surfaces facet into neutral crystallographic planes to minimize their surface energy. This assumption is based on the seminal work of Henrich which has shown faceting of the MgO(111) surface into {100} planes giving rise to three sided pyramids that have been observed by scanning electron microscopy. These surfaces had been prepared by mechanical polishing and phosphoric acid etching, followed by Ar+ sputtering and 1400 K annealing in ultra-high vacuum (UHV). More recent reflection electron microscopy studies of MgO(111) surfaces, annealed in the presence of oxygen at higher temperatures, have revealed relatively flat surfaces stabilized by an oxygen rich reconstruction. In this work we employ a combination of optical microscopy, transmission electron microscopy, and electron holography to further study the issue of surface faceting.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

Post Oxidation Anneal and Re-Oxidation Effects in 5 nm SiO2 Films

1986 ◽  
Vol 76 ◽  
Author(s):  
L. Dori ◽  
M. Arienzo ◽  
Y. C. Sun ◽  
T. N. Nguyen ◽  
J. Wetzel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Dioxide ◽  
Oxygen Vacancies ◽  
Interface Roughness ◽  
Cross Sectional ◽  
Oxide Charge ◽  
Transmission Electron ◽  
Redistribution Of Hydrogen ◽  
Transmission Electron Microscopy Cross

ABSTRACTUltrathin silicon dioxide films, 5 nm thick, were grown in a double-walled furnace at 850°C in dry O2. A consistent improvement in the electrical properties is observed following the oxidation either with a Post-Oxidation Anneal (POA) at 1000°C in N2 or with the same POA followed by a short re-oxidation (Re-Ox) step in which 1 nm of additional oxide was grown. We attribute these results to the redistribution of hydrogen and water related groups as well as to a change in the concentration of sub-oxide charge states at the Si-SiO2 interface. A further improvement observed after the short re-oxidation step had been attributed to the filling of the oxygen vacancies produced during the POA. High resolution Transmission Electron Microscopy cross-sectional observations of the Si-iSO2 interface have evidenced an increase in the interface roughness after the thermal treatment at high temperature. These results are in agreement with recent XPS data.

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