Structural Study of SIC/AIN Bilayers and Trilayers on SI and 6H-SIC

1994 ◽  
Vol 339 ◽  
Author(s):  
D. Prasad Beesabathina ◽  
K. Fekade ◽  
K. Wongchotigul ◽  
M. G. Spencer ◽  
L. Salamanca-Riba
Keyword(s):  
Electron Microscopy ◽  
Amorphous Layer ◽  
Growth Morphology ◽  
Epitaxial Relationship ◽  
Nucleation Layer ◽  
Single Crystalline ◽  
Bulk Layer ◽  
Transmission Electron ◽  
Columnar Grains ◽  
Lattice Images

ABSTRACTThe growth morphology and microstructure of SiC/AlN/6H-SiC, SiC/AlN/SiC/Si, and SiC/AlN/Si heterostructures grown by LPCVD were studied using transmission electron microscopy. The SiC/AIN bilayers grown on 6H-SiC substrates were single crystalline and comprised of 3C-SiC and 2H-AlN. The epitaxial relationship between 2H-AlN and 6H-SiC is [0001]AlN//[0001]SiC. The SiC/AlN/SiC trilayers and the SiC/AIN bilayer grown on (001)Si were composed of 3H-SiC and 2H-AlN. However, the 2H-AlN layer was polycrystalline even though the (001)3C-SiC was single crystalline. The preferred orientation of the AlN layers in SiC/AlN/SiC/Si and SiC/AlN/Si are [0112] and [0002], respectively. The AlN/3C-SiC interface is relatively sharp compared to the AIN/Si interface in which an amorphous layer close to the interface was observed. In general, the polycrystalline AlN structure has two distinct layers: (1) nucleation layer and (2) bulk layer. High resolution lattice images of the polycrystalline AlN showed amorphous areas and small misoriented crystallites in the nucleation layer. The bulk layer consists of preferentially oriented large columnar grains.

Electron Microscopy of InN Films

1989 ◽  
Vol 162 ◽  
Author(s):  
J. S. Morgan ◽  
T. J. Kistenmacher ◽  
W. A. Bryden ◽  
T. O. Poehler
Keyword(s):  
Electron Microscopy ◽  
Defect Structure ◽  
Growth Morphology ◽  
Plan View ◽  
Mechanical Abrasion ◽  
Transmission Electron ◽  
Morphology And Structure ◽  
Columnar Grains ◽  
Amorphous Quartz ◽  
Scanning Electron

ABSTRACTThis paper describes growth morphology and structure of rfmagnetron sputtered thin films of InN, studied by plan-view transmission electron microscopy (TEM) and by scanning electron microscopy (SEM). Films deposited on TEM grids, (0001) sapphire, (111) silicon and amorphous quartz were prepared for TEM by mechanical abrasion of the substrate followed by sputter etching. At low deposition temperatures (<400°C), films consisted of small, basal-oriented, columnar grains. Above 500°C, growth consisted of larger, faceted, basal-oriented, mesa-island grains. Observations of growth morphology and defect structure are correlated with structural, compositional and electrical properties.

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.

Transmission Electron Microscopy of Evaporated Perylene Thin Films

1990 ◽  
Vol 48 (2) ◽  
pp. 336-337
Author(s):  
C. Ewins ◽  
J.R. Fryer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Electronics ◽  
High Vacuum ◽  
Amorphous Layer ◽  
Electric Heater ◽  
Transmission Electron ◽  
Polycyclic Aromatic

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.

scholarly journals Spore Coat Architecture of Clostridium novyi NT Spores

2007 ◽  
Vol 189 (17) ◽  
pp. 6457-6468 ◽  
Author(s):  
Marco Plomp ◽  
J. Michael McCaffery ◽  
Ian Cheong ◽  
Xin Huang ◽  
Chetan Bettegowda ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Anaerobic Bacterium ◽  
Amorphous Layer ◽  
Spore Coat ◽  
Experimental Animals ◽  
Force Microscopy ◽  
Atomic Force ◽  
Clostridium Novyi ◽  
Transmission Electron

ABSTRACT Spores of the anaerobic bacterium Clostridium novyi NT are able to germinate in and destroy hypoxic regions of tumors in experimental animals. Future progress in this area will benefit from a better understanding of the germination and outgrowth processes that are essential for the tumorilytic properties of these spores. Toward this end, we have used both transmission electron microscopy and atomic force microscopy to determine the structure of both dormant and germinating spores. We found that the spores are surrounded by an amorphous layer intertwined with honeycomb parasporal layers. Moreover, the spore coat layers had apparently self-assembled, and this assembly was likely to be governed by crystal growth principles. During germination and outgrowth, the honeycomb layers, as well as the underlying spore coat and undercoat layers, sequentially dissolved until the vegetative cell was released. In addition to their implications for understanding the biology of C. novyi NT, these studies document the presence of proteinaceous growth spirals in a biological organism.

scholarly journals High-resolution transmission electron microscopy on KHx–GIC's

1986 ◽  
Vol 1 (1) ◽  
pp. 177-186 ◽  
Author(s):  
L. Salamanca-Riba ◽  
N.-C. Yeh ◽  
M. S. Dresselhaus ◽  
M. Endo ◽  
T. Enoki
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Deuterium Content ◽  
X Ray Diffraction ◽  
High Hydrogen ◽  
Intermediate Phases ◽  
Transmission Electron ◽  
Final Compound ◽  
Lattice Images ◽  
Hydrogen Deuterium

The in-plane and c-axis structure of KHx—GIC's and KDy—GIC's is studied using transmission electron microscopy (TEM) and x-ray diffraction as a function of intercalation temperature and time. With the TEM, two commensurate in-plane phases are found to coexist in these compounds with relative concentrations depending on intercalation conditions. When the direct intercalation method is used, the first step of intercalation is the formation of a stage n potassium-GIC and the final compound is a stage n KHx—GIC (or KDy—GIC). Highresolution (00l) lattice images show direct evidence for intermediate phases in the intercalation process. These intermediate phases are hydrogen (deuterium) deficient and are found at the boundary between pure potassium regions and regions with high hydrogen (deuterium) content. A comparison of the structure for the two methods of intercalation of KH is also presented.

Microstructural Characterization of GaN Grown on SiC

2019 ◽  
Vol 25 (6) ◽  
pp. 1383-1393
Author(s):  
Sabyasachi Saha ◽  
Deepak Kumar ◽  
Chandan K. Sharma ◽  
Vikash K. Singh ◽  
Samartha Channagiri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Metal Organic

AbstractGaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.

Metalorganic Molecular Beam Epitaxy of Magnesium Oxide on Silicon

2000 ◽  
Vol 619 ◽  
Author(s):  
F. Niu ◽  
B.H. Hoerman ◽  
B.W. Wessels
Keyword(s):  
Thin Films ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Amorphous Layer ◽  
Film Structure ◽  
Gate Insulator ◽  
Oxide Semiconductor ◽  
Epitaxial Relationship ◽  
Transmission Electron ◽  
Metalorganic Molecular Beam Epitaxy

ABSTRACTEpitaxial cubic MgO thin films were deposited on single crystal Si (001) substrates by metalorganic molecular beam epitaxy (MOMBE) using the solid precursor magnesium acetylacetonate as the source and an RF excited oxygen plasma as the oxidant. The growth process involved initial formation of an epitaxial β-SiC interlayer followed by direct deposition of a MgO overlayer. The film structure was characterized by X-ray diffraction as well as conventional and high-resolution transmission electron microscopy. Both the MgO overlayer and β-SiC interlayer had an epitaxial relationship such that MgO (001) (or SiC (001)) // Si (001) and MgO [110] (or SiC [110])// Si [110]. No evidence of an amorphous layer was observed at either the MgO/SiC or SiC/Si interface. Dielectric properties of the epitaxial MgO thin films on Si (001) were evaluated from capacitance-voltage (C-V) characteristic of metal-oxide-semiconductor (MOS) structures. The C-V measurements indicated an interface trap density at midgap as low as 1011 to 1012 cm−2 eV−1 and fixed oxide charge of the order of 1011/ cm2, respectively. These results indicate that epitaxial MgO deposited by MOMBE has potential as a gate insulator.

Quantitative Investigations of Interfaces and Grain Boundaries by Phase Contrast Electron Microscopy with Ultra High Resolution

2001 ◽  
Vol 7 (S2) ◽  
pp. 288-289
Author(s):  
C. Kisielowski ◽  
J.M. Plitzko ◽  
S. Lartigue ◽  
T. Radetic ◽  
U. Dahmen
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Phase Contrast ◽  
Recent Progress ◽  
Image Interpretation ◽  
Present Contribution ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Contrast Microscopy ◽  
Lattice Images

Recent progress in High Resolution Transmission Electron Microscopy makes it possible to investigate crystalline materials by phase contrast microscopy with a resolution close to the 80 pm information limit of a 300 kV field emission microscope'"". A reconstruction of the electron exit wave from a focal series of lattice images converts the recorded information into interpretable resolution. The present contribution illustrates some recent applications of this technique to interfaces.Fig. 1 shows a reconstructed electron exit wave of a heterophase interface between GaN and sapphire. The experiment takes advantage of three factors: First, we resolved the GaN lattice in projection, which requires at least 0.15 nm resolution. The projection eliminates the stacking fault contrast that usually obscures lattice images in the commonly recorded projection. Thus, image interpretation is drastically simplified. Second, all atom columns at the interface and in the sapphire are resolvable with a smallest projected aluminum - oxygen spacing of 85 pm in the sapphire.

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