scholarly journals Investigation of a short-period (001) HgTe-Hg0.6Cd0.4Te superlattice by transmission electron microscopy

1994 ◽  
Vol 9 (12) ◽  
pp. 2217-2223 ◽  
Author(s):  
X F Zhang ◽  
C R Becker ◽  
H Zhang ◽  
L He ◽  
G Landwehr
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Transmission Electron ◽  
Short Period

Double Periodicity Formation in EuTe/PbTe Superlattices

1995 ◽  
Vol 399 ◽  
Author(s):  
M. Shima ◽  
L. Salamanca-Riba ◽  
G. Springholz ◽  
G. Bauer
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Short Period Superlattices

ABSTRACTMolecular beam epitaxy was used to grow EuTe(x)/PbTe(y) short period superlattices with x=1-4 EuTe(111) monolayers alternating with y≈3x PbTe monolayers. The superlattices were characterized by transmission electron microscopy and high resolution x-ray diffraction. Regions with double periodicity were observed coexisting with areas of nominal periodicity. The sample with x=3.5 and y=9, for example, contains regions with double periodicity of x=7 and y=17. X-ray diffraction measurements confirm the formation of the double periodicity in these samples by the appearance of weak satellites in between the satellites of the nominal periodicity. The double periodicity in the superlattice is believed to result from interdiffusion during the growth. A model for this process is presented.

Transmission Electron Microscopy of AlxGa1-xN/SiC multilayer structures

1994 ◽  
Vol 52 ◽  
pp. 844-845
Author(s):  
W. T. Pike ◽  
T. George ◽  
M. A. Khan ◽  
J. N. Kuznia
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Band Gap ◽  
Basal Plane ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Lattice Match ◽  
Transmission Electron ◽  
Solar Blind ◽  
Short Period

The potential of wide-band-gap III-V nitrides as solar-blind ultraviolet sensors and light emitters has prompted an increasing amount of work recently, including the fabrication of the first UV sensors from as-deposited single crystal GaN. We have used high resolution transmission electron microscopy (TEM) to study the microstructure of two novel developments of wideband-gap III-V nitrides: the growth of ultra-short period GaN/AlN superlattices (digital alloys); and the incorporation of SiC layers into AlxGa1-xN structures. By varying the relative periods in a GaN/AIN superlattice, it should bepossible to tailor the band gap of the composite to lie between the elemental values of 365nm for GaN and 200nm for AIN. The group IV semiconductor, SiC, has a close lattice match (< 3%) to AlxGa1-xN forgrowth on the basal plane. Demonstration of epitaxial growth for AlxGa1-xN/SiC multilayers could enable an extension of direct band-gap material towards the visible.The superlattice samples were grown by low-pressure metalorganic chemical-vapor deposition (MOCVD)using a unique switched atomic-layer-epitaxy (SALE) procedure (as first used by Dapkus et al. for GaAs). GaN was grown on the basal-plane sapphire substrates above a thin AlN layer, which has been foundto maximize the crystalline quality of the GaN film.

Height Measurement of Interplanetary Dust Particles by Scanning Transmission Electron Microscopy (STEM)

2000 ◽  
Vol 8 (6) ◽  
pp. 46-49
Author(s):  
David J. Joswiak
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Source Region ◽  
Interplanetary Dust ◽  
Asteroid Belt ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Height Measurement ◽  
Transmission Electron ◽  
Short Period

Interplanetary dust particles (IDPs) comprise an important source of extraterrestrial materials available for study of our solar system and originate from either the asteroid belt or from short period comets. IDPs from cometary sources are particularly important as they constitute the only physical samples of comets available; all known meteorites are derived from the asteroids, the Moon or Mars. By measuring the densities of IDPs and using an appropriate atmospheric entry heating model, it is possible to determine whether an individual IDP has been derived from an asteraidal or cometary source region. Calculating the density of an IDP requires knowledge of both its mass and volume, which can be determined by using a combination of secondary and transmission electron microscopy techniques. We have developed methods to measure both of these parameters and thus routinely measure densities for individual IDPS in the size range of 5-15 μm.

Structural Characterization of Short-Period SimGEn Superlattices by Transmission Electron Microscopy and X-Ray Diffraction

1991 ◽  
Vol 220 ◽  
Author(s):  
W. Jäger ◽  
K. Leifer ◽  
P. Ehrhart ◽  
E. Kasper ◽  
H. Kibbel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Interface Roughness ◽  
Buffer Layers ◽  
X Ray Diffraction ◽  
Average Composition ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period

ABSTRACTHigh resolution and analytical transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to characterize short-period strained-layer Sim-Gen superlattices ( m monolayers Si, n monolayers Ge, total number of periods N≤ 145, total thickness ≃ 200 nm). The superlattices were grown by low-temperature molecular beam epitaxy (T = 300–400°C) on different SiGe alloy buffer layers on Si (100)substrates. The combination of these two methods shows that detailed informations can be obtained about superlattice periodicity, interface roughness, strain, and average composition.

scholarly journals Структурная характеризация короткопериодной сверхрешетки на основе гетероструктуры CdF-=SUB=-2-=/SUB=-/CaF-=SUB=-2-=/SUB=-/Si(111) методами просвечивающей электронной микроскопии и рентгеновской дифрактометрии

2021 ◽  
Vol 47 (15) ◽  
pp. 3
Author(s):  
Л.М. Сорокин ◽  
Р.Н. Кютт ◽  
В.В. Ратников ◽  
А.Е. Калмыков
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Fragment Size ◽  
Diffraction Curve ◽  
X Ray ◽  
Transmission Electron ◽  
Short Period ◽  
Lateral Inhomogeneity

A detailed study of the structure of a short-period superlattice based on alternating layers of cadmium and calcium fluorides, grown by molecular beam epitaxy on a Si (111) substrate, by transmission electron microscopy and X-ray diffractometry, has been carried out. It was found that the superlattice is in a pseudomorphic state, and a lateral inhomogeneity with a fragment size of 10 - 40 nm was found. The reason for the broadening of the main and satellite peaks of the SL on the (111) diffraction curve has been clarified.

Preparation of Transmission Electron Microscopy specimens of integrated circuits usinga modified tripod polisher

1994 ◽  
Vol 52 ◽  
pp. 872-873
Author(s):  
Howard Shishido ◽  
David Su
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Integrated Circuits ◽  
Integrated Circuit ◽  
Specific Area ◽  
Specimen Preparation ◽  
Critical Dimensions ◽  
The Past ◽  
Transmission Electron ◽  
Short Period

With the continuous decrease in the critical dimensions of integrated circuit (IC) devices, transmission electron microscopy (TEM) has become an important tool for the study of these devices. Two reasons account for the new emphasis in TEM - small fabrication imperfections that did not affect the performance of devices in the past can no longer be ignored and thus need to be addressed, the dimensions of some features, such as gate oxide thicknesses, have become so small that only TEM can be used reliably to study them. However, as the need for TEM increases, the requirements for specimen preparation also has become more stringent. No longer is it acceptable to blindly prepare samples of blanket films or of any one of an array of devices, the ability to "hit" a specific area in a very short period of time has become a necessity. Fortunately, recent advances in the preparation of TEM specimens of IC devices has relieved some of the pressure of performing these jobs.

Sign in / Sign up

Export Citation Format

Share Document