Effect of Microstructure on Phase Formation in Reaction of The Nb/Al Multilayer Thin Films

1991 ◽  
Vol 230 ◽  
Author(s):  
Katayun Barmak ◽  
Kevin R. Coffey ◽  
David A. Rudman ◽  
Simon Foner
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Diagram ◽  
Grain Boundary ◽  
Phase Formation ◽  
Boundary Diffusion ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Thin Layers ◽  
Multilayer Thin Films

AbstractWe investigated the phase formation sequence in the reaction of multilayer thin films of Nb/Al with overall compositions of 25 and 33 at.% AI. We report novel phenomena which distinguish thin-film reactions unequivocally from those in bulk systems. For sufficiently thin layers composition and stability of product phases are found to deviate significantly from that predicted from the equilibrium phase diagram. We demonstrate that in the Nb/Al system the length scales below which such deviations occur is about 150 nm. We believe that these phenomena occur due to the importance of grain boundary diffusion and hence microstructure in these thin films.

Thermal Grooving in Single versus Multilayer Thin Films

2004 ◽  
Vol 854 ◽  
Author(s):  
Peter M. Anderson ◽  
Jue Wang ◽  
Sridhar Narayanaswamy
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Boundary ◽  
Multilayer Thin Films ◽  
Multilayer Thin Film ◽  
Penetration Distance ◽  
Grain Boundary Grooves ◽  
Single Versus

ABSTRACTA 2D analytic result is presented for the penetration distance P of grain boundary grooves as a function of time t during heating and straining of polycrystalline multilayer thin films with immiscible phases. These grooves can ultimately pinch off individual layers. The result shows that P ∼ t0.25 initially and P ∼ t at longer time. This new analysis contrasts single- versus multilayer thin film response.

Effect of Concentration Gradient on Phase Stability

1982 ◽  
Vol 19 ◽  
Author(s):  
K.N. Tu ◽  
U. GöSele
Keyword(s):  
Thin Film ◽  
Phase Diagram ◽  
Intermetallic Compound ◽  
Phase Stability ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Metal Films ◽  
Silicide Formation ◽  
Intermetallic Compound Growth ◽  
Form Alone

ABSTRACTA feature of thin film reaction that is different from the reaction in bulk samples is the tendency to form a single intermetallic compound rather than all of them which are allowed according to the equilibrium phase diagram. For example, in thin film silicide formation, Pd2Si has been found to form alone and to grow as a layer between Pd and Si. The silicide is stable over a wide temperature range of 100 to 700°C. The phenomenon of single intermetallic compound growth is not unique to silicide formation between transition metal films and silicon, but is also commonly observed in reactions between bimetallic thin films. The phenomenon indicates phase stability.

Investigation of Grain Boundary Diffusion in Thin Films by SNMS Technique

2011 ◽  
Vol 312-315 ◽  
pp. 1208-1215 ◽  
Author(s):  
Dezső L. Beke ◽  
A. Lakatos ◽  
G. Erdélyi ◽  
A. Makovecz ◽  
G.A. Langer ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Numerical Solutions ◽  
Grain Boundary Diffusion ◽  
Bimodal Structure ◽  
Layer Interface ◽  
Cap Layer ◽  
Film Interface

It was shown more recently in our Laboratory [1,2,3] that having a substrate/diffusant/thin-film/cap-layer structure (the thin film was typically several 10 nm thick, with the same order of magnitude of grain size; the refractory metal cap layer was used just to avoid the oxidation), first the diffusant atoms migrated very fast across the thin film and segregated at the film/cap-layer interface. The accumulated atoms at the film/cap layer interface form a secondary diffusion reservoir and atoms diffuse back to the layer. Later on, the thin film was gradually filled up with the diffusing atoms and composition depth profiles, determined by Secondary Neutral Mass Spectroscopy (SNMS), showed a maximum at the cap layer-thin film interface. The accumulated atoms at this interface formed a secondary diffusion reservoir and atoms diffused back to the layer. These observations can be interpreted supposing a bimodal grain boundary structure with different (fast and low) diffusivities. The observed grain boundary diffusion phenomena can be classified as C-type diffusion. The appearance of the peak observed at the cap layer interface can be used as a tool to determine the grain boundary diffusivity along the fast boundaries. Because the fast boundaries were saturated in the first stage of the process, this back-diffusion took place along the low-diffusivity boundaries only. Thus the SNMS depth-profiling is a good method to determine grain boundary diffusivities in a bimodal structure. In addition, from the overall impurity content inside the film the segregation can also be estimated, if the bulk solubility is low and the GB density is known. Numerical simulations of C-type GB diffusion in thin films with a bimodal structure confirmed that the interpretation of the result depicted above is reasonable [4]. In order to estimate roughly the GB diffusion data we determined the fast diffusivity using the first appearance method. The lower diffusivity was determined from the time evolution of the broadening of the diffusant/thin film interface. In addition both (slow and fast) diffusivities were also estimated from fitting numerical solutions obtained in [4] too.

Metastable and equilibrium phase formation in sputter-deposited Ti/Al multilayer thin films

2002 ◽  
Vol 91 (12) ◽  
pp. 9575 ◽  
Author(s):  
G. Lucadamo ◽  
K. Barmak ◽  
C. Lavoie ◽  
C. Cabral ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Equilibrium Phase ◽  
Multilayer Thin Films ◽  
Sputter Deposited

High-Throughput Evaluation of Crystallization Temperature of Pd-Cu-Si System Using Integrated Thin Film Samples

2010 ◽  
Vol 654-656 ◽  
pp. 2426-2429 ◽  
Author(s):  
Yuko Aono ◽  
Junpei Sakurai ◽  
Akira Shimokohbe ◽  
Seiichi Hata
Keyword(s):  
Thin Film ◽  
Phase Diagram ◽  
Amorphous Alloy ◽  
High Throughput ◽  
Crystallization Temperature ◽  
Evaluation Method ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
The Difference ◽  
Si Thin Film

In this paper, a new high-throughput evaluation method for crystallization temperature (Tx) of thin film amorphous alloy is introduced. For measurement of Tx on integrated thin film samples, thermography is used. The order of one hundred Pd-Cu-Si thin film amorphous samples with different composition are integrated on one chip and measured their Tx at once. The validity of measured Tx are examined by comparing with results of differential scanning calorimeter that is a conventional method for Tx measurement, and equilibrium phase diagram of Pd-Si. As results, the difference of two methods is within 10 K and the trend of Tx map has strong correlation with the phase diagram, respectively.

Stress Effects on Al and Al(Cu) Thin Film Grain-Boundary Diffusion

1999 ◽  
Vol 594 ◽  
Author(s):  
X.-Y. Liu ◽  
C.-L. Liu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Atomistic Simulations ◽  
Stress Effects ◽  
Stress States ◽  
And Migration ◽  
Cu Thin Film

AbstractStress effects on grain-boundary diffusion in Al and Al(Cu) thin films are evaluated through atomistic simulations. Specifically, the grain-boundary vacancy formation and migration and interstitial migration energetics are obtained as a function of stress states in thin film. In general, the activation energies vary at a rate of 0.1 eV per 1.0 % strain at the grain boundary investigated, indicating the possible impact on electromigration phenomenon in these films.

Characterization of reactive phase formation in sputter-deposited Ni/Al multilayer thin films using TEM

1996 ◽  
Vol 54 ◽  
pp. 1000-1001
Author(s):  
G. Lucadamo ◽  
K. Barmak ◽  
C. Michaelsen
Keyword(s):  
Thin Films ◽  
Phase Formation ◽  
Dark Field ◽  
Nickel Layer ◽  
Multilayer Thin Films ◽  
Cross Sectional ◽  
Dark Field Imaging ◽  
Transmission Electron ◽  
Sputter Deposited ◽  
Constant Heating

The subject of reactive phase formation in multilayer thin films of varying periodicity has stimulated much research over the past few years. Recent studies have sought to understand the reactions that occur during the annealing of Ni/Al multilayers. Dark field imaging from transmission electron microscopy (TEM) studies in conjunction with in situ x-ray diffraction measurements, and calorimetry experiments (isothermal and constant heating rate), have yielded new insights into the sequence of phases that occur during annealing and the evolution of their microstructure.In this paper we report on reactive phase formation in sputter-deposited lNi:3Al multilayer thin films with a periodicity A (the combined thickness of an aluminum and nickel layer) from 2.5 to 320 nm. A cross-sectional TEM micrograph of an as-deposited film with a periodicity of 10 nm is shown in figure 1. This image shows diffraction contrast from the Ni grains and occasionally from the Al grains in their respective layers.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

Peculiarities of Intermetallic Phase Formation in the Process of a Solid State Reaction in (Al/Cu)n Multilayer Thin Films

JOM ◽  
2021 ◽  
Author(s):  
Evgeny T. Moiseenko ◽  
Sergey M. Zharkov ◽  
Roman R. Altunin ◽  
Oleg V. Belousov ◽  
Leonid A. Solovyov ◽  
...  
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Phase Formation ◽  
Solid State Reaction ◽  
Intermetallic Phase ◽  
Multilayer Thin Films

Intermetallic Formation in the Aluminum–Copper System

2003 ◽  
Vol 10 (04) ◽  
pp. 677-683 ◽  
Author(s):  
E. B. Hannech ◽  
N. Lamoudi ◽  
N. Benslim ◽  
B. Makhloufi
Keyword(s):  
Electron Microscopy ◽  
Phase Diagram ◽  
Solid Solution ◽  
Intermetallic Layer ◽  
Equilibrium Phase ◽  
Equilibrium Phase Diagram ◽  
Diffusion Couples ◽  
Intermetallic Formation ◽  
Parabolic Law ◽  
Scanning Electron

Intermetallic formation at 425°C in the aluminum–copper system has been studied by scanning electron microscopy using welded diffusion couples. Several Al–Cu phases predicted by the equilibrium phase diagram of the elements and voids taking place in the diffusion zone have been detected in the couples. The predominant phases were found to be Al 2 Cu 3 and the solid solution of Al in Cu, α. The growth of the intermetallic layer obeyed the parabolic law.

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