Interfacial Reactions Between Co and GaAs

1988 ◽  
Vol 119 ◽  
Author(s):  
F.-Y. Shiau ◽  
Y. Zuo ◽  
X.-Y. Zheng ◽  
J.-C. Lin ◽  
Y. A. Chang
Keyword(s):  
Thin Film ◽  
Phase Diagram ◽  
Bulk Diffusion ◽  
Interfacial Reactions ◽  
Diffusion Couples ◽  
Diffusion Data

AbstractInterfacial reactions between Co and GaAs have been studied using bulk diffusion couples of Co (∼0.5 mm thick)/GaAs and thin-film Co(∼-40 nm) on (001)GaAs as well as the epitaxial formation of CoAs and CoGa on (001)GaAs. In addition, phase diagram of Co-Ga-As at 600°C was determined. The thin-film results are rationalized in terms of the phase diagram and bulk diffusion data.

Interfacial Reactions Between Ni and GaAs

1987 ◽  
Vol 102 ◽  
Author(s):  
J. C. Lin ◽  
X. -Y. Zheng ◽  
K. -C. Hsieh ◽  
Y. A. Chang
Keyword(s):  
Thin Film ◽  
Phase Diagram ◽  
Epitaxial Growth ◽  
Ternary Phase ◽  
Bulk Diffusion ◽  
Interfacial Reactions ◽  
Diffusion Couples ◽  
Phase Diagram Determination

ABSTRACTInterfacial reactions between Ni and GaAs have been studied using bulk diffusion couples of Ni(∼0.5mm thick)/GaAs and thin-film Ni (∼40nm) on GaAs (100) in addition to phase diagram determination at 600° C. On the basis of the phase diagram and the bulk diffusion couples, the ternary phase which forms first in the thin-film couples is Ni3 GaAs. Thinfilm studies show that the epitaxial growth of equilibrium contact phases, i.e., NiAs and β-GaNi, on a GaAs (100) substrate is possible.

Interfacial Reactions in Thin Film and Bulk Iron/Silicon Couples

1997 ◽  
Vol 472 ◽  
Author(s):  
Yuhong Zhang ◽  
Douglas G. Ivey
Keyword(s):  
Thin Film ◽  
Initial Phase ◽  
Bulk Diffusion ◽  
Electron Beam Evaporation ◽  
Interfacial Reactions ◽  
Diffusion Couples ◽  
Si Substrates ◽  
Formation Behavior ◽  
Scanning Electron ◽  
Oriented Single Crystal

ABSTRACTInitial phase formation in thin film and bulk Fe/Si couples has been investigated using transmission and scanning electron microscopy (TEM and SEM). For the thin film couples, ≈165 nm of Fe was deposited by electron beam evaporation onto <111> oriented Si substrates. SiO2 capping layers (≈100nm thick) were used to protect the Fe from oxidation during subsequent annealing. Bulk diffusion couples were fabricated by clamping together polycrystalline Fe pieces and <111> oriented single crystal Si pieces and sealed in evacuated (≈10-4 torr) quartz capsules. Annealing of thin film couples was done at temperatures ranging from 300°C to 500°C for up to several hours. Bulk couples were annealed at 700°C for up to ≈1000hrs.Interfacial reactions were detected in as deposited thin film couples. A layer =5nm thick was identified, through electron diffraction, as poorly crystalline off-stoichiometric Fe3Si. Iron was the major diffuser during the formation of Fe3Si. During annnealing off-stoichiometric Fe3Si transformed to stoichiometric Fe3Si. FeSi was the next phase to form - initially detected after annealing at 300°C for 3 hrs. Similar results were obtained for bulk couples. The first phase to form was ordered stoichiometric Fe3Si (initially detected after 7 hrs), followed by FeSi (≈23 hrs) and then FeSi2 (>200 hrs). The formation behavior of these phase is discussed.

Analysis of the diffusion controlled growth of cobalt silicides in bulk and thin film couples

1995 ◽  
Vol 10 (5) ◽  
pp. 1134-1145 ◽  
Author(s):  
T. Barge ◽  
P. Gas ◽  
F.M. d'Heurle
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Size ◽  
Diffusion Coefficients ◽  
Bulk Diffusion ◽  
Diffusion Couples ◽  
Laws Of Growth ◽  
Diffusion Controlled ◽  
Two Factors ◽  
Cobalt Silicides

The solid state reaction between Co and Si has been studied in bulk diffusion couples between 850 and 1100 °C. At the scale of the observations made, the three phases Co2Si, CoSi, and CoSi2 are found to grow simultaneously, according to diffusion controlled kinetics. The results are analyzed in term of the Nernst-Einstein equation that directly relates diffusion fluxes to the free energy changes driving the formation. The growth rates obtained for CoSi2 at high temperatures, in the present bulk samples, are compared with those determined by others in thin films, at much lower temperatures. The comparison requires that attention should be paid to two factors. The first one is that the laws of growth are slightly different for a phase growing simultaneously with two other ones (bulk) and one phase growing alone (thin films). The second factor is the grain size of the various samples, which varies with the temperature of reaction. Once this is done, excellent agreement is obtained between the two sets of measurements. Moreover it is shown that knowing the grain size, it is possible to calculate quite accurately the growth rate from the respective isotope diffusion coefficients both for lattice and grain boundaries of Co and Si in CoSi2.

Reactions between palladium and gallium arsenide: Bulk versus thin-film studies

1988 ◽  
Vol 3 (1) ◽  
pp. 148-163 ◽  
Author(s):  
J. -C. Lin ◽  
K. -C. Hsieh ◽  
K. J. Schulz ◽  
Y. A. Chang
Keyword(s):  
Thin Film ◽  
Phase Formation ◽  
Ternary Phase ◽  
Film Studies ◽  
Bulk Diffusion ◽  
Diffusion Path ◽  
Solution Phase ◽  
Stable Configuration ◽  
Diffusion Couples ◽  
Initial Formation

Reactions between Pd and GaAs have been studied using bulk-diffusion couples of Pd (∼0.6 mm thick) /GaAs and thin-film Pd (50 and 160 nm)/GaAs samples. The sequence of phase formation at 600°C between bulk Pd and GaAs was established. Initial formation of the solution phase μ and the ternary phase T does not represent the stable configuration. The stable configuration is GaAs |∊|Λ|γ|ν|Pd and is termed the diffusion path between GaAs and Pd. The sequence of phase formation for the bulk-diffusion couples is similar at 500°C. Phase formation for the thin-film Pd/GaAs specimens was studied at 180,220,250,300,350,400,450,600, and 1000°C for various annealing times. The sequence of phase formation obtained from the thin-film experiments is rationalized readily from the known ternary phase equilibria of Ga–Pd–As and the results from the bulk-diffusion couples of Pd/GaAs. The thin-film results reported in the literature are likewise rationalized. The diffusion path concept provides a useful guide in understanding the phase formation in Pd–GaAs interface or any other M-GaAs interface. This information is important in designing a uniform, stable contact for the metallization of GaAs.

Differences Between the Growth Kinetics of Thin Film and Bulk Diffusion Couples

1981 ◽  
Vol 10 ◽  
Author(s):  
U. Gösele ◽  
K. N. Tu
Keyword(s):  
Thin Film ◽  
Equilibrium Phase ◽  
Interface Reaction ◽  
Bulk Diffusion ◽  
Equilibrium Phase Diagram ◽  
Specific Reference ◽  
Second Phase ◽  
Diffusion Couples ◽  
Reaction Barriers ◽  
Equilibrium Phases

It is proposed that interface reaction barriers in binary A/B diffusion couples lead to the absence of phases predicted by the equilibrium phase diagram, provided that the diffusion zones are sufficiently thin (“thin film case”). With increasing thickness of the diffusion zones the influence of interface reaction barriers decreases and the simultaneous existence of diffusion-controlled growth of all equilibrium phases is expected (“bulk case”). First-phase and different modes of second-phase formation in the diffusion zones as well as the influence of impurities are discussed with specific reference to silicide formation. For this discussion the concept of a critical thickness of the first forming phase is introduced, below which a second compound phase cannot grow simultaneously with the first one.

Nb Contacts to GaAs: Thermal Stability and Phase Formation

1987 ◽  
Vol 108 ◽  
Author(s):  
Kevin J. Schulz ◽  
Xiang-Yun Zheng ◽  
Y. Austin Chang
Keyword(s):  
Thin Film ◽  
Thermal Stability ◽  
Film Studies ◽  
Bulk Diffusion ◽  
Diffusion Path ◽  
Diffusion Couples ◽  
Compound Formation ◽  
The Stability ◽  
Binary Compounds ◽  
Thermal Stability Of

ABSTRACTThe applicability of Nb as a Schottky barrier on GaAs depends to a large extent on the thermal stability of the contacts. In this study, bulk diffusion couple and phase diagram studies in addition to thin film studies were completed to understand the stability of and the reactions at the Nb/GaAs interface. Nb thin films were deposited onto GaAs substrates by dc magnetron sputtering and were annealed in the temperature range 300 to 1000°C. Analysis was done using plan-TEM and XTEM. The Nb/GaAs interface was found to break down into a series of binary compounds above 500°C. Bulk diffusion couples annealed at 600°C were analyzed using an electron microprobe. The stable sequence of phases formed in the couple, i.e., the diffusion path, was determined and was used to rationalize the observed compound formation in the thin film contact system.

Reaction couples of ceramic thin films prepared by CVD

1988 ◽  
Vol 46 ◽  
pp. 798-799
Author(s):  
D.W. Susnitzky ◽  
S.R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Thin Film ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Solid State Reactions ◽  
Spatial Distributions ◽  
Diffusion Couples ◽  
Kinetics Studies ◽  
Ceramic Thin Films ◽  
Initial Stage

Solid-state reactions have traditionally been studied in the form of diffusion couples. This ‘bulk’ approach has been modified, for the specific case of the reaction between NiO and Al2O3, by growing NiAl2O4 (spinel) from electron-transparent Al2O3 TEM foils which had been exposed to NiO vapor at 1415°C. This latter ‘thin-film’ approach has been used to characterize the initial stage of spinel formation and to produce clean phase boundaries since further TEM preparation is not required after the reaction is completed. The present study demonstrates that chemical-vapor deposition (CVD) can be used to deposit NiO particles, with controlled size and spatial distributions, onto Al2O3 TEM specimens. Chemical reactions do not occur during the deposition process, since CVD is a relatively low-temperature technique, and thus the NiO-Al2O3 interface can be characterized. Moreover, a series of annealing treatments can be performed on the same sample which allows both Ni0-NiAl2O4 and NiAl2O4-Al2O3 interfaces to be characterized and which therefore makes this technique amenable to kinetics studies of thin-film reactions.

TEM STUDIES OF THE MICROMECHANISMS OF SOLID STATE REACTIONS IN Ni-Zr BULK DIFFUSION COUPLES

1990 ◽  
Vol 51 (C4) ◽  
pp. C4-121-C4-130
Author(s):  
U. KÖSTER ◽  
R. PRIES ◽  
G. BEWERNICK ◽  
B. SCHUHMACHER ◽  
M. BLANK-BEWERSDORFF
Keyword(s):  
Solid State ◽  
Bulk Diffusion ◽  
Solid State Reactions ◽  
Diffusion Couples
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