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.

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.

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.

The Growth Rates of Intermediate Phases in Co/Si Diffusion Couples: Bulk Versus Thin-Film Studies

1989 ◽  
Vol 148 ◽  
Author(s):  
C. H. Jan ◽  
J. C. Lin ◽  
Y. A. Chang
Keyword(s):  
Experimental Data ◽  
Growth Rates ◽  
Film Studies ◽  
Bulk Diffusion ◽  
Diffusion Equations ◽  
Diffusion Couples ◽  
Intermediate Phases ◽  
Diffusion Controlled ◽  
Composition Profiles ◽  
Interdiffusion Coefficients

ABSTRACTBulk diffusion couples of Co/Si were annealed at 800, 900, 1000, 1050 and 1100°C for periods ranging from 24 hours to one month. Growth rates of the intermediate phases, Co2Si, CoSi and CoSi2, as well as the composition profiles across the couples were determined by optical microscopy and electron probe microanalysis (EPMA). Using the solution to the multiphase binary diffusion equations and the experimental data, the interdiffusion coefficients for Co2Si, CoSi and CoSi2 are obtained as a function of temperature. The activation energies obtained are 140, 160 and 190 KJ/mole for Co2Si, CoSi and CoSi2, respectively. The generally small interdiffusion coefficient of CoSi2 and its high activation energy cause the growth rate of CoSi2 to be extremely small at low temperatures.The interdiffusion coefficients for Co2Si, CoSi and CoSi2 at 545°C are obtained by extrapolation of the high-temperatures data. Using these data and solving numerically the diffusion equations with the appropriate boundary conditions, the growth of Co2Si, CoSi and CoSi2 is calculated as a function of time. The calculated results are in good agreement with the experimental data reported in the literature. This study demonstrates clearly that the initial absence of the CoSi2 phase is due to diffusion-controlled rather than nucleation-controlled kinetics. This phenomenon may be quite common in many thin-fiflm metal/Si couples.

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.

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.

Decagonal Al3Pd Phase Formation in Lateral and Conventional Thin Film Al/Pd Diffusion Couples.

1990 ◽  
Vol 187 ◽  
Author(s):  
B. Blanpain ◽  
J.W. Mayer
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Phase Formation ◽  
Solid State Reaction ◽  
Initial Growth ◽  
Diffusion Couples ◽  
Decagonal Phase

AbstractWe show that the decagonal Al3Pd phase can be formed by solid state reaction in lateral and conventional thin film couples of Al and Pd. The metastable decagonal phase forms after the initial growth of the Al3Pd2 compound.

Growth of intermediate phases in Co/Si diffusion couples: Bulk versus thin‐film studies

1993 ◽  
Vol 73 (3) ◽  
pp. 1168-1179 ◽  
Author(s):  
Chia‐Hong Jan ◽  
Chia‐Ping Chen ◽  
Y. Austin Chang
Keyword(s):  
Thin Film ◽  
Film Studies ◽  
Diffusion Couples ◽  
Intermediate Phases

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.

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