The Formation and Cathodoluminescence Activity of Buffer Layer Edge Dislocations in In0.12Ga0.88As/GaAs Heterostructures

1987 ◽  
Vol 104 ◽  
Author(s):  
E. A. Fitzgerald ◽  
P. D. Kirchner ◽  
G. D. Petit ◽  
J. M. Woodall ◽  
D. G. Ast
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Buffer Layer ◽  
Defect Structure ◽  
Radiative Recombination ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Gaas Buffer Layer ◽  
Edge Dislocations

ABSTRACTThe defect structure of lattice-mismatched one micron In0.12 Ga0.88As epilayers on (001) GaAs was studied with scanning cathodoluminescence (CL) and transmission electron microscopy (TEM). CL examination of the GaAs buffer layer revealed the formation of a segmented network of defects below the interface. Cross-sectional TEM analysis shows that these defects are dislocation half-loops extending from the interface, and the vast majority of these loops lie on the GaAs side of the interface. The dislocations in the GaAs buffer layer were determined to be edge dislocations. Thus, CL images show that edge dislocations in this system are centers for non-radiative recombination. We propose that two 60° dislocations with opposite screw and interface tilt components can glide into the buffer layer to form edge dislocations. Potential energy plots for 60° dislocations near the interface and interacting with interface dislocations supports this model.

TEM Analysis of Planar Defects in InGaAsN and GaAs Grown on Ge (001) by MOVPE

2016 ◽  
Vol 675-676 ◽  
pp. 639-642
Author(s):  
Pornsiri Wanarattikan ◽  
Sakuntam Sanorpim ◽  
Somyod Denchitcharoen ◽  
Visittapong Yordsri ◽  
Chanchana Thanachayanont ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Buffer Layer ◽  
Growth Direction ◽  
Dark Field ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Planar Defects ◽  
Transmission Electron ◽  
Gaas Buffer Layer ◽  
Field Emission Electron Microscopy

InGaAsN on Ge (001) is proposed to be a part of the InGaP(N)/InGaAs/InGaAsN/Ge four-junction solar cell to increase a conversion efficiency over 40%. In this work, InGaAsN lattice-matched film and GaAs buffer layer grown on Ge (001) substrate by metal organic vapor phase epitaxy (MOVPE) were examined by transmission electron microscopy (TEM). Electron diffraction pattern of InGaAsN taken along the [110]-zone axis illustrates single diffracted spots, which represent a layer with a uniformity of alloy composition. Cross-sectional bright field TEM image showed line contrasts generated at the GaAs/Ge interface and propagated to the InGaAsN layer. Dark field TEM images of the same area showed the presence of boundary-like planar defects lying parallel to the growth direction in the InGaAsN film and GaAs buffer layer but not in the Ge substrate. TEM images with the (002) and (00-2) reflections and the four visible {111} planes reflections illustrated planar defects which are expected to attribute to antiphase boundaries (APBs). Moreover, the results observed from atomic force microscopy (AFM) and field emission electron microscopy (FE-SEM) demonstrated the surface morphology of InGaAsN film with submicron-sized domains, which is a characteristic of the APBs.

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.

Nanoindentation in Tin/Nbn Multilayers and Thin Films Examined Using Transmission Electron Microscopy

1999 ◽  
Vol 5 (S2) ◽  
pp. 776-777
Author(s):  
S.J. Lloyd ◽  
J.E. Pitchford ◽  
J.M. Molina-Aldareguia ◽  
Z.H. Barber ◽  
M.G. Blamire ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Deformation Structure ◽  
Tem Analysis ◽  
Repeat Distance ◽  
Cross Sectional ◽  
Thin Coatings ◽  
Transmission Electron ◽  
Salt Structure ◽  
Interesting System

Nanoindentation allows the hardness of thin coatings and synthetic multilayer structures to be measured, since indentation depths can be as little as a few 10s of nm. In combination with the cross-sectional transmission electron microscopy (TEM) analysis described here it is possible to observe the deformation structure under an indent, and potentially to understand deformation mechanisms on a nm scale in a wide variety of materials. Synthetic multilayers are a particularly interesting system to investigate. Variations in hardness with the multilayer compositional repeat distance (A) have been reported for several systems. The highest hardnesses, which are in excess of what a simple “rule of mixtures” would predict, occur in nitride multilayers at A ∼5nm. Here we present some preliminary results showing the deformation structure in both a monolithic NbN film and a TiN/NbN multilayer in which both components have the rQck salt structure with lattice parameters 0.424nm (TiN) and 0.439nm (NbN).

Tem Assessment of Defects in (CdHg)Te Heterostructures

1990 ◽  
Vol 216 ◽  
Author(s):  
S.G. Lawson-Jack ◽  
I.P. Jones ◽  
D.J. Williams ◽  
M.G. Astles
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Buffer Layer ◽  
High Density ◽  
Misfit Dislocations ◽  
Cross Sectional ◽  
Burgers Vector ◽  
Density Of Dislocations ◽  
Transmission Electron ◽  
Interfacial Plane

ABSTRACTTransmission electron microscopy has been used to assess the defect contents of the various layers and interfaces in (CdHg) Te heterostructures. Examination of cross sectional specimens of these materials suggests that the density of misfit dislocations at the interfaces is related to the layer thicknesses, and that the high density of dislocations which are generated at the GaAs/CdTe interface are effectively prevented from penetrating into the CdHgTe epilayer by a 3um thick buffer layer. The majority of the dislocations in the layers were found to have a Burgers vector b = a/2<110> and either lie approximately parallel or inclined at an angle of ∼ 60° to the interfacial plane.

CROSS-SECTIONAL TRANSMISSION ELECTRON MICROSCOPY OF DEFORMED MICROSTRUCTURES IN MONOLITHIC AND MULTILAYER TiSiN/TiN FILMS

2010 ◽  
Vol 24 (01n02) ◽  
pp. 18-25 ◽  
Author(s):  
P. C. WO ◽  
P. R. MUNROE ◽  
Z. F. ZHOU ◽  
Z. H. XIE ◽  
K. Y. LI
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Multilayer Coating ◽  
Multilayer Coatings ◽  
Shear Cracks ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Columnar Grains ◽  
Edge Cracks

The deformation microstructures generated by nanoindentation of multilayer coatings consisting of TiSiN layers alternating with ten TiN interlayers, were examined by cross-sectional transmission electron microscopy (XTEM). Two multilayered coatings were studied: a thin TiSiN coating interlayered with thick TiN interlayer and a thick TiSiN coating alternated with thin TiN layers. A monolithic TiSiN coating was also examined for comparison. Surface morphology of the samples was found to be variable. Both surface roughness and coating hardness increase with the thickness of the outermost TiSiN layer. All samples show columnar structures, and for the multilayer coatings, epitaxial growth of these columnar grains through the TiSiN / TiN multilayers was observed. Stair-shaped shear cracks can be seen in the multilayer coating alternated with thick TiN interlayers, whereas radial and edge cracks are observed in the coating multilayered with thin TiN layers and in the monolithic coating. TEM analysis also suggests that columnar grains help to resist the initiation of edge cracks. Compared to other studies on similar coating systems with fewer periods of interlayers, the deformation observed here appears less severe, indicating an improvement in the strength of the coating through increasing the number of interlayers.

Cross-Sectional Transmission Electron Microscopy of Defects in Beta Silicon Carbide Thin Films

1985 ◽  
Vol 46 ◽  
Author(s):  
C.H. Carter ◽  
J.A. Edmond ◽  
J.W. Palmour ◽  
J. Ryu ◽  
H.J. Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Silicon Carbide ◽  
Vapor Deposition ◽  
Defect Structure ◽  
Chemical Vapor ◽  
Processing Parameters ◽  
Cross Sectional ◽  
Transmission Electron

AbstractTechniques have been developed at NCSU for fabricating cross-sectional transmission electron microscopy (XTEM) foils from monocrystalline beta silicon carbide thin films grown by chemical vapor deposition. The results of the TEM observations are utilized to discern the efficacy of the various processing parameters in terms of film quality and defect structure as well as oxidation, ion implantation and annealing procedures.

Structure of Shear Bands in Zirconium-Based Metallic Glasses Observed by Transmission Electron Microscopy

2002 ◽  
Vol 754 ◽  
Author(s):  
Xiaofeng Gu ◽  
Kenneth J. T. Livi ◽  
Todd C. Hufnagel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metallic Glasses ◽  
Defect Structure ◽  
Shear Bands ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Before And After ◽  
High Resolution Tem ◽  
Band Spacing

ABSTRACTWe have used transmission electron microscopy (TEM) to investigate the structure of shear bands produced by bending electron-transparent Zr52.5Cu17.9Ni14.6Al10Ti5 metallic glass specimens. Shear bands were located by comparing the structure of the specimens before and after deformation. The shear band spacing is influenced by the structure of the specimen; portions of the specimen with a significant population of nanocrystals show a smaller separation between shear bands. Quantitative high resolution TEM analysis based on ratio technique has been used to explore the defect structure in shear bands. High density and void-like defects with size of about 1 nm were found in shear bands formed in both amorphous and nanocrystalline areas. A simple model was proposed to explain the formation of these defects.

Controlled Growth of GaAs/AlAs(111)B Superlattices

1992 ◽  
Vol 263 ◽  
Author(s):  
J.E. Angelo ◽  
J.W. Hoehn ◽  
A.M. Dabiran ◽  
P.I. Cohen ◽  
W.W. Gerberich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Defect Structure ◽  
Molecular Beam ◽  
Substantial Reduction ◽  
Flux Ratio ◽  
Cross Sectional ◽  
Temperature Growth ◽  
Transmission Electron

ABSTRACTIn this study, transmission electron microscopy (TEM) was used to investigate the growthconditions which produce the highest quality GaAs(111)B films by molecular beam epitaxy (MBE). Low-temperature growth using both As4 and arsine as an As2 source produced highly twinned structures, although the use of As4 provided for a smoother surface and slightly different defect structure. Two distinct twin boundaries, (112)A and (112)B, were identified by cross-sectional transmission electron microscopy (XTEM). The (112)A defect could be over-grown by a subsequent high temperature growth but the roughness associated with the (112)B defects only increased with further growth. High temperature growth of GaAs and AlAs films, while maintaining the GaAs(11)surface reconstruction, resulted in substantial reduction in the number of twins boundaries. We also found that GaAs(111)B layer quality and surface morphology can be further improved by a high temperature growth with low arsenic to Ga flux ratio of I to 1.5 ona slightly misoriented substrate.

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.

Transmission Electron Microscopy of an Aluminum-Silver-Stainless Steel Solid State Bond

1985 ◽  
Vol 43 ◽  
pp. 172-173
Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Specimen Preparation ◽  
Dimensional Control ◽  
Tem Analysis ◽  
Metal Parts ◽  
Dissimilar Metal ◽  
Transmission Electron ◽  
Short Time

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.

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