Thin-film compound phase formation at Fe–Ge and Cr–Ge interfaces

2003 ◽  
Vol 18 (8) ◽  
pp. 1900-1907 ◽  
Author(s):  
O. M. Ndwandwe ◽  
C. C. Theron ◽  
T. K. Marais ◽  
R. Pretorius
Keyword(s):  
Thin Film ◽  
Phase Formation ◽  
Rutherford Backscattering Spectrometry ◽  
Heat Of Formation ◽  
Miedema Model ◽  
Formation Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effective Heat Of Formation ◽  
Transformation Enthalpy

Phase formation was studied in the Fe–Ge and Cr–Ge thin-film systems by means of Rutherford backscattering spectrometry and x-ray diffraction. In the Fe–Ge system, FeGe was the first phase to form while in the Cr–Ge system, Cr11Ge8 was found to form first. The results are compared with the predictions of the effective heat of formation model. Heats of formation were calculated using the Miedema model. The effect of the transformation enthalpy term ΔHtr, used to convert a semiconducting element into a hypothetical metallic one in the Miedema model, is also discussed.

Prediction of First Phase Formation at Au-METAL Interfaces Using the Effective Heat of Formation Model

1991 ◽  
Vol 238 ◽  
Author(s):  
R. Pretorius ◽  
T. K. Marais ◽  
A. E. Muller ◽  
D. Knoesen
Keyword(s):  
Phase Formation ◽  
Binary Systems ◽  
Heat Of Formation ◽  
Liquidus Curve ◽  
Effective Concentration ◽  
Formation Model ◽  
Growth Interface ◽  
Effective Heat ◽  
Metal Interfaces ◽  
Effective Heat Of Formation

ABSTRACTThe effective heat of formation model enables heats of formation to be calculated as a function of concentration. By choosing the effective concentration at the growth interface to be that of the liquidus minimum, the model correctly predicL. first phase formation for 14 binary systems for which experimental data was found, except for the Au-Cu system which does not have a well-defined minimum on the liquidus curve.

Synthesis and thermodynamic evaluation of intermetallic Mg-Ni/Mg-Cu nanoscale powders

2009 ◽  
Vol 24 (8) ◽  
pp. 2503-2510 ◽  
Author(s):  
Jun-Peng Lei ◽  
Xing-Long Dong ◽  
Fu-Guo Zhao ◽  
Hao Huang ◽  
Xue-Feng Zhang ◽  
...  
Keyword(s):  
Physical Vapor Deposition ◽  
Arc Discharge ◽  
Heat Of Formation ◽  
Thermodynamic Evaluation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Physical Vapor Deposition Method ◽  
Effective Heat Of Formation ◽  
Good Agreement

Nanometer-sized intermetallic Mg-Ni and Mg-Cu compound powders were prepared by a physical vapor deposition method (arc discharge) and characterized by means of x-ray diffraction and transmission electron microscopy. Based on an empirical specific heat equation, the effective heat of formation and its temperature dependence were calculated to explain phase formation in nanoscale powders of the binary Mg-Ni and Mg-Cu systems. It is shown that theoretic calculations are in good agreement with the experimental observations.

Phase formation sequence induced by deposition temperatures in Nb/Si multilayers

1998 ◽  
Vol 13 (5) ◽  
pp. 1373-1378 ◽  
Author(s):  
Ming Zhang ◽  
W. K. Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Formation ◽  
Room Temperature ◽  
Heat Of Formation ◽  
Silicide Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Transmission Electron

The phase formation sequence in Nb/Si multilayers formed at different deposition temperatures was investigated by x-ray diffraction (XRD) and transmission electron microscopy (TEM). The amorphous phases were found to form in Nb/Si multilayers deposited at room temperature and 560 °C, but the compositions of these two amorphous phases were different. The crystalline Nb3Si and Nb5Si3 were formed in Nb/Si multilayers deposited at 180–500 °C. The interfacial energy and modified heat of formation are adopted to explain our obtained results. The occurrence of crystalline Nb5Si3, NbSi2, and amorphous silicide phase was found when the Nb/Si multilayers with Nb3Si phase were annealed at 550 °C, while only NbSi2 was found to form when annealing this sample at 700 °C. The mobility of Si takes an important role in phase formation in Nb/Si multilayers.

Phase Formation in Ti-Al-N MAX-Phase Contacts to GaN

2009 ◽  
Vol 615-617 ◽  
pp. 947-950 ◽  
Author(s):  
Michał A. Borysiewicz ◽  
Eliana Kamińska ◽  
Anna Piotrowska ◽  
Iwona Pasternak ◽  
Rafał Jakieła ◽  
...  
Keyword(s):  
Thin Film ◽  
Mass Spectrometry ◽  
Phase Formation ◽  
Ohmic Contacts ◽  
Secondary Ion Mass Spectrometry ◽  
Max Phase ◽  
X Ray Diffraction ◽  
Max Phases ◽  
X Ray ◽  
Secondary Ion

Presented are the results of studies on Ti-Al-N MAX phase formation in thin film multilayers of Ti, Al and TiN deposited on n-type GaN by magnetron sputtering. Two approaches to phase formation are shown, annealing Ti-Al-TiN multilayers at 600oC in argon and annealing Ti/Al multilayers at 600oC in nitrogen. Samples are characterized by means of High Resolution X-Ray Diffraction and Secondary Ion Mass Spectrometry profiling. As MAX phases are very stable at high temperatures the potential of their application as ohmic contacts to n-GaN devices is discussed.

Phase Formation and Phase Stability in the Al-Ti Thin Film System

1990 ◽  
Vol 213 ◽  
Author(s):  
L.R. Parks ◽  
D.A. Lilienfeld ◽  
P. BØRgesen ◽  
R. Raj
Keyword(s):  
Thin Film ◽  
Phase Stability ◽  
Rutherford Backscattering Spectrometry ◽  
Intermetallic Phases ◽  
Film System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Annealing Temperatures ◽  
Thin Film System ◽  
Sequential Formation

ABSTRACTThis study focuses on the sequential formation of aluminide phases during annealing of titanium and aluminum thin film bilayers. The formation of titanium-rich intermetallic phases at higher annealing temperatures is emphasized. Using Rutherford Backscattering Spectrometry (RBS) analysis, and x-ray diffraction, phases formed as a function of temperature have been identified. The phases Al3Ti through Ti3Al were observed over the temperature range 450–750°C, where reaction with the SiO2 substrate occurred. All phases were present as discreet layers within the samples with several layered phases coexisting at the higher temperatures.

Effects of High Energy Ion Irradiation on Crystallization of Amorphous Germanium Films Deposited on Calcium Fluoride Substrates

1995 ◽  
Vol 396 ◽  
Author(s):  
Setsuo Nakao ◽  
Kazuo Saitoh ◽  
Masami Ikeyama ◽  
Hiroaki Niwa ◽  
Seita Tanemura ◽  
...  
Keyword(s):  
Thin Film ◽  
Calcium Fluoride ◽  
Structural Changes ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Irradiation ◽  
High Energy ◽  
The Other ◽  
Ion Current ◽  
X Ray Diffraction ◽  
X Ray

AbstractAmorphous (a-) Ge films were deposited on air-cleaved CaF2 (111) substrates at different deposition temperatures (Td). The films were irradiated with 0.9 MeV Ge or Si ions at low ion current intensity (1c) l00nA/cm2. Their structural changes were studied by Rutherford backscattering spectrometry (RBS) -channeling technique and thin film x-ray diffraction (XRD) measurement. It was found that the films were epitaxially crystallized by Ge and Si ion irradiation although they included randomly oriented grains. Ge ion irradiation was more effective for the crystallization than Si ion irradiation. However, the amount of the randomly oriented grains was slightly higher when using Ge ions. On the other hand, ion irradiation to the films prepared at high Td also exhibited higher incidence of randomly oriented grains.

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