Metallurgical Reactions in Au/Ge/Au Contact to Gallium Arsenide

1986 ◽  
Vol 77 ◽  
Author(s):  
Taeil Kim ◽  
DDL Chung ◽  
S Mahajan
Keyword(s):  
Gaas Substrate ◽  
Ternary Phase ◽  
Annealing Temperature ◽  
Interfacial Structure ◽  
Lattice Image ◽  
Au Film ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Current Flows ◽  
Metallurgical Reactions

ABSTRACTTransmission electron microscopy (TEM), was used to study the interfacial structure resulting from the alloying reaction of a Au/Ge/Au film on (100) GaAs. The metallurgical reaction at 400°C results in the previously unknown hexagonal Au3Ga phase. The crystal structure of the AuoGa phase is proposed based on the observed diffraction patterns and the lattice image The well-known fcchcp coherent jnterface is observed between Au and Au3Ga such that (111)Au // (0001)Au3Ga and [110]. // [1120]Au2Ga. In addition to Au3Ga, other Au-Ga compounds (Au7Ga2, Au2Ge), a Au-Ge metastabil phase, and a Au-Ge-As ternary phase were observed after annealing. After annealing above 400°C, epitaxially regrown GaAs crystallites on the underlying GaAs substrate were revealed by cross-section TEM. The current flows through these Ge-doped regrown GaAs regions and the contact becomes ohmic The size and density of the regrown GaAs crystallite increase with increasing annealing temperature between 400 and 500°C; this explains the decreasing tendency of contact resistance with increasing annealing temperature.

HRTEM Study of Structure and Evolution of Highly Mismatched Heteroepitaxial Interface, GaSe/GaAs(100)

1998 ◽  
Vol 523 ◽  
Author(s):  
Z.R. Dai ◽  
S. R. Chegwidden ◽  
F. S. Ohuchi
Keyword(s):  
Thin Film ◽  
Intermediate Layer ◽  
Gaas Substrate ◽  
Structural Model ◽  
Rhombohedral Structure ◽  
Lattice Image ◽  
Thin Film System ◽  
Transmission Electron ◽  
Relationship Of ◽  
The Relationship

AbstractThe microstructural evolution of the GaSe/GaAs(100) thin film system was characterized by high resolution transmission electron microscopy (HRTEM). The relationship of crystallographic orientation between the GaSe thin film and the GaAs substrate is [011]GaAs ‖ [1100]GaSe/(100)GaAs ‖ (0001)GaSe, with the dominant polytype for the GaSe thin film being a γ-type which has a 3R-rhombohedral structure with R3m space group. An intermediate layer was observed between the GaAs substrate and the GaSe thin film, with a structure distinct from that of either GaAs or GaSe. The result of a fast Fourier transform (FFT) of the lattice image corresponding to the intermediate layer indicated that its crystal structure was associated with that of α-Ga2Se3. A new vacancy ordered structural model of β-Ga2Se3 was suggested.

scholarly journals Investigation of Lithiated Carbons by Transmission Electron Microscopy and X-Ray Diffraction Analysis

1998 ◽  
Vol 548 ◽  
Author(s):  
T. D. Tran ◽  
X. Y. Song ◽  
K. Kinoshita
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Black ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Lattice Image ◽  
X Ray ◽  
Storage Mechanism ◽  
Transmission Electron ◽  
Diffraction Patterns

ABSTRACTThe microstructures of lithiated synthetic graphite and carbon black were studied by high- resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analysis. Information about the crystal structure of carbon containing various Li compositions can provide useful insights to our understanding of the Li storage mechanism in carbonaceous materials. Samples with compositions of Li0.93C6or Li0.45C6 were found to contain both stage-one and stage-two compounds. These observations are consistent with XRD data. The changes in sample microstructure as the results of lithiation and exposure to electron irradiation were observed by TEM and recorded over several minutes in the microscope environment. Selected area electron diffraction patterns indicated that the lithiated samples quickly changed composition to LiC 24, which appeared to dominate during the brief analysis period. The layer planes in the lattice image of a disordered carbon black after Li insertion are poorly defined, and changes in the microstructure of these lithiated carbons was not readily apparent. Observations on these lithium intercalation compounds as well as the limitation of the experimental procedure will be presented.

Characterization of Interfacial Structure in Large Lattice Mismatch Heteroepitaxy: Ag/Si (111)

1990 ◽  
Vol 209 ◽  
Author(s):  
D.C. McKenna ◽  
G.-C. Wang ◽  
K. Rajan
Keyword(s):  
Lattice Mismatch ◽  
Interfacial Structure ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Interfacial Structures ◽  
Large Lattice ◽  
Large Lattice Mismatch ◽  
Diffraction Patterns

ABSTRACTThe interfacial structure of a large lattice mismatched (˜25%) (111) Ag-Si system was studied by using transmission electron diffraction (SADP - Selected Area Diffraction Pattern). The epitaxial films of Ag (600–1200Å) were grown by MBE on flat Si(111) and misoriented Si(1ll) surfaces. We have examined the interfacial structures of the Ag on 2° misoriented Si(111) using diffraction patterns of cross sectional view. Through a detail analysis of thelocation and shape of the diffraction spots, we can determine the epitaxial relationship between Ag and Si, the small tilt angle of Ag(111) planes withrespect to the misoriented Si(111), the period of the finite terrace size of the misoriented Si substrate, and the size of the ordered region in the Ag film. The O-lattice analysis developed by Bollmann has beenapplied to this interface andthe result is compared with the SADP observation.

Electron microscopy characterization of monoclinic SiAs precipitates in heavily As+-implanted silicon

1991 ◽  
Vol 6 (8) ◽  
pp. 1701-1710 ◽  
Author(s):  
A. Armigliato ◽  
A. Parisini
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Small Precipitate ◽  
Diffraction Patterns ◽  
Microscopy Characterization ◽  
First Time

Silicon wafers have been implanted with As+ ions at an energy of 100 keV and a dose of 1 × 1017 cm−2 and subsequently annealed at 1050°for 15 min. This results in a peak As concentration of 7 × 1021 cm−3, which is far beyond the solid solubility value of arsenic in silicon at this annealing temperature. Rod-like precipitates, dislocations, and small precipitate-like defects have been observed by transmission electron microscopy. From the analysis of several diffraction patterns taken on a number of rod-like particles at different tilt angles, it has been unambiguously found that they have the structure of the monoclinic SiAs compound previously reported in literature. The stoichiometry of the precipitates has been confirmed by x-ray microanalysis. To our knowledge, this is the first time that this SiAs phase is detected in As+-implanted silicon.

Primitive clay precursors formed on feldspar

1987 ◽  
Vol 24 (3) ◽  
pp. 506-527 ◽  
Author(s):  
Kazue Tazaki ◽  
W. S. Fyfe
Keyword(s):  
Major Element ◽  
Depth Profiling ◽  
Original Structure ◽  
Lattice Image ◽  
Reactive Iron ◽  
Transmission Electron ◽  
Lattice Images ◽  
Diffraction Patterns ◽  
Clay Layers ◽  
Clay Formation

High-resolution transmission electron microscopy of clay formation on K-feldspar has revealed the existence of intermediate states between feldspar and crystalline clay products. During the earliest weathering stages of K-feldspar, a primitive clay precursor forms on the feldspar surface that is spotted by ion oxides. This reactive iron is incorporated into the primitive clay precursors, which have an ultrathin 150–200 Å (1 Å = 0.1 nm) circular form and 14–20 Å lattice images or long, curled fiber forms with varied lattice image spacings. The electron diffraction patterns of primitive clay precursors show diffuse rings at 2.65, 2.04, and 1.51 Å, suggesting low crystallinity, random orientation, and partial inheritance of the original structure. EDX step scanning analysis showed that the major-element concentrations of Si, Al, and K tend to decrease from unaltered parts to altered parts of precursors with substantial increase in Fe. Auger depth profiling showed the thickness of the primitive clay layers is 150–300 Å. The primitive clay precursors may well precede formation of spheroidal particles of halloysite, squat cylinders of halloysite or hexagonal crystalline, and tabuler halloysite (7 Å). SEM, XRD, SIMS, and SAM data support the TEM results.

A STUDY ON THE PRECIPITATION OF Ge-RICH NANOPARTICLES IN A LUMINESCENT (Er, Ge) CO-DOPED SiO2 FILM SPUTTERED WITH Ar + O2 PLASMA

2006 ◽  
Vol 05 (04n05) ◽  
pp. 493-498
Author(s):  
C. L. HENG ◽  
Y. J. LI ◽  
J. MAYANDI ◽  
T. G. FINSTAD ◽  
S. JØRGENSEN ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Rf Magnetron Sputtering ◽  
Sio2 Film ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Diffraction Patterns ◽  
Amorphous States ◽  
Co Doped

We report the photoluminescence (PL) from an ( Er , Ge ) co-doped SiO 2 film deposited by rf-magnetron sputtering in an Ar + O 2 ambience. The sample film was annealed in N 2 for 30 min at different temperatures. The PL intensity increases as the annealing temperature increases from 700 to 1000°C, and drops to very weak after 1100°C annealing. High-resolution transmission electron microscopy (TEM) observation shows that there are some Ge -rich nanoparticles precipitated after 700°C annealing, and more clusters precipitated after 1000°C annealing. However, no Ge nanocrystals were found in these films, the diffraction patterns are always halo which indicates that the precipitated clusters are in amorphous states. X-ray photoelectron spectroscopy (XPS) analysis indicates the Ge in the nanoclusters is mostly in an oxidized state and the oxidation state of Er increases with increasing annealing temperature.

scholarly journals Phase Formation Sequence In The Pd-Gaas System

1985 ◽  
Vol 54 ◽  
Author(s):  
T. Sands ◽  
V. G. Keramidas ◽  
A. J. Yu ◽  
K. M. Yu ◽  
R. Gronsky ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Formation ◽  
Ternary Phase ◽  
Annealing Temperature ◽  
Large Angle ◽  
Second Phase ◽  
X Rays ◽  
Morphological Aspects ◽  
Transmission Electron ◽  
Phase Phase

ABSTRACTThe morphological aspects of ternary phase formation during the Pd-GaAs reaction have been studied by application of transmission electron microscopy (TEM) and Rutherford backscattering (RBS) techniques. The TEM images show that the first product phase, “phase I”, forms during deposition of Pd onto (100) GaAs and exhibits the preferred orientation [0001]I ∼ // [011]GaAs. In the presence of unreacted Pd, the second phase, “phase II”, nucleates at large-angle grain boundaries in the phase I film as the annealing temperature increases above ∼ 250°C Energy dispersive analysis of x-rays and RBS suggest that both phases I and II have nominal compositions in the range of Pd3GaAs to Pd4GaAs.

Microstructural Evolution of Co2GaAs Thin Film on GaAs Substrate

1995 ◽  
Vol 399 ◽  
Author(s):  
D.W. Shin ◽  
C.G. Park ◽  
J.S. Kwak ◽  
H.K. Baik
Keyword(s):  
Thin Film ◽  
Gaas Substrate ◽  
Ternary Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Eds Analysis ◽  
Transmission Electron ◽  
Unit Cells ◽  
Cobalt Thin Films ◽  
Cobalt Thin Film

ABSTRACTInterfacial reactions and epitaxial growth of the microstructure between cobalt thin film and (100)-oriented GaAs substrate have been studied, using X-ray diffraction, transmission electron microscopy and EDS analysis. Cobalt thin films were deposited by e-beam evaporation, and were subsequently annealed at 400 °C.The reaction layer evolved due to the annealing was identified as the ternary phase, Co2GaAs, that was grown epitaxially on the substrate. The new orientation relationship between Co2GaAs and GaAs substrate was found as <110>Co2GaAs // <100>GaAs and {001}Co2GaAs // {011}GaAs. These results can be well explained upon matching the unit cells of Co2GaAs and GaAs. Upon the annealing at 600°C, the Co2GaAs phase is usually decomposed to stable binary phases, CoGa and CoAs.

Interfacial Characterization and Electrical Properties of Co/GaSb Contacts

2018 ◽  
Vol 928 ◽  
pp. 215-220
Author(s):  
Kun Lin Lin ◽  
Yu Chieh Cheng ◽  
Tung Huan Chou
Keyword(s):  
Energy Dispersive Spectrometry ◽  
Annealing Temperature ◽  
Field Effect Transistors ◽  
High Current Density ◽  
Oxide Semiconductor ◽  
Transmission Line Model ◽  
Transmission Electron ◽  
Specific Contact ◽  
Diffraction Patterns ◽  
P Type

The microstructures of Co–GaSb junctions in samples annealed at 300, 400, 500, and 600°C in a N2atmosphere were characterized using transmission electron microscopy (TEM) in combination with energy-dispersive spectrometry (EDS), nanobeam electron diffraction (NBD), and the selected area diffraction patterns (SADPs). The isolated CoSb3(Ga) phase started to form at the interface of Co/GaSb in the temperature of 400°C and then the CoSb3(Ga) phase changed to a continues layer at the interface when the annealing temperature was increased to 500°C. Upon increasing the temperature to 600°C, a large amount of Ga from GaSb diffused out toward Co to form a CoGa layer. The specific contact resistivity of Co/GaSb contact was evaluated by circular transmission line model (CTLM) and indicated that the lowest value was 5.410-4Ω-cm at annealing temperature of 500°C and possessed high current density of 41.7 A/cm2at 1V. These results indicate that the annealing temperature of the Co/GaSb structure could be maintained below 500°C for the successful formation of low-resistance metal Co/GaSb contacts in GaSb-based p-type metal-oxide-semiconductor field-effect transistors.

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

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