Solid Phase Heteroepitaxy of Barium Ferrite on Sapphire

1992 ◽  
Vol 280 ◽  
Author(s):  
Michael A. Parker ◽  
T. L. Hylton ◽  
K. R. Coffey ◽  
J. K. Howard
Keyword(s):  
Film Thickness ◽  
Barium Ferrite ◽  
Solid Phase ◽  
Amorphous Films ◽  
New Process ◽  
Dimensional Growth

ABSTRACTA new process for the crystallization of amorphous films on chemically dissimilar substrates, solid phase heteroepitaxy (SPHE), is described. Unlike SPE in Si, it is found that the kinetics can be modeled by nucleation and multi-dimensional growth with Johnson-Mehl kinetics modified for the effects of a finite film thickness and nucleation initiated at the interface with the substrate.

Crystallization and Melting of Amorphous Silicon on a Microsecond Time Scale

1986 ◽  
Vol 74 ◽  
Author(s):  
G. L. Olson ◽  
J. A. Roth ◽  
E. Nygren ◽  
A. P. Pogany ◽  
J. S. Williams
Keyword(s):  
Film Thickness ◽  
Time Scale ◽  
Laser Heating ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Amorphous Films ◽  
Random Nucleation ◽  
Cw Laser ◽  
Time Regime ◽  
Amorphous Si

AbstractMeasurements of the competition beween solid phase epitaxy, solid phase random nucleation, and melting in amorphous Si on a microsecond time scale are reported. We find that the behavior of amorphous Si under microsecond pulsed dye laser irradiation depends strongly on film thickness and temperature. In “thin” (≲1000 Å) films solid phase epitaxy is observed at temperatures up to and exceeding 1300°C with random nucleation dominating at T>1330° C; however, melting of amorphous Si does not occur. In contrast, in “thick” (2600 Å) amorphous films melting is observed at T˜1190°C. These results are discussed with respect to measurements obtained previously in the nanosecond time regime using Q-switched laser heating and in the 0.1–1 millisecond regime using “chopped beam” cw laser heating.

The dance of snow-lines

2020 ◽  
Author(s):  
James Owen
Keyword(s):  
High Resolution ◽  
Planet Formation ◽  
Solid Phase ◽  
Outer Region ◽  
Vapour Phase ◽  
Vital Role ◽  
Sublimation Temperature ◽  
New Process ◽  
High Resolution Images ◽  
Protoplanetary Discs

<p>Snow-lines are thought to play a vital role in the evolution of protoplanetary discs and planet formation at all scales. Snow-lines occur in regions of the protoplanetary discs where the temperature reaches the sublimation temperature and volatiles transition from the solid phase to the vapour phase (or vice-versa). However, in the outer region of protoplanetary discs (beyond a few AU), the temperature is set by the distribution of solids and their ability to absorb stellar light. Thus, the thermodynamics of the disc and the volatile phases are inextricably linked. In this talk, I will show this coupling is thermally unstable, and snow-lines continually evolve in regions of the disc that are marginally optically thick. Patches of the disc proceeding through a limit cycle, where volatiles in a region of the disc continually condense and then sublimate. Using numerical simulations of the CO snow-line I will show it can move 10s AU over 10,000 years, repeatedly. I will use these simulations to discuss how this new process may effect measured Carbon abundances, solid evolution and ultimately planet formation, making connections to high-resolution images of protoplanetary discs. </p>

Optimization of Passive Isolator Based On Barium Ferrite Sputtered Films

2004 ◽  
Vol 833 ◽  
Author(s):  
M. Le Berre ◽  
S. Capraro ◽  
J. P. Chatelon ◽  
T. Rouiller ◽  
B. Bayard ◽  
...  
Keyword(s):  
Film Thickness ◽  
Barium Ferrite ◽  
Rf Magnetron Sputtering ◽  
Magnetic Film ◽  
Line Length ◽  
Microwave Range ◽  
Reciprocal Effect ◽  
Standard Design ◽  
Lift Off ◽  
Insertion Losses

ABSTRACTFerrites have magnetic properties suitable for electronic applications, especially in the microwave range (circulators and isolators). Hexagonal ferrite, such as barium ferrite (BaFe12O19 or BaM), which have a large resistivity and high permeability at high frequencies are of great interest for microwave device applications.This contribution deals with BaM films, 1 to 36 microns thick, which were deposited under optimized conditions by RF magnetron sputtering. The films were then crystallized using a 800°C thermal annealing. Isolators were then realized using patterning of coplanar wave guides with standard lift-off technique. The slots and the central width were 300 μm wide, gold was used for the conductor lines. We evaluated the influence of various parameters on the device performances: the magnetic film thickness, the positioning of the magnetic film (CPW deposited onto the magnetic film or directly on the substrate) and the CPW metallic thickness. As standard design, the CPW were deposited on the top of the magnetic film. For the first design, transmission coefficients showed a non reciprocal effect, which reaches 7 dB per cm of line length at 50 GHz for a 26.5 μm thick BaM film. Both the insertion losses and the non-reciprocal effect measured increased with the magnetic film thickness with a saturation effect. In the second design where the CPW is deposited directly on the substrate, the BaM film was selectively wet etched prior to the metal deposition everywhere except between the conductors. In that case we measured that the non reciprocal effect reached high values for lower BaM thicknesses than in comparison to design # 1 and that the insertion losses also decreased. Moreover for the design # 2, also in relation with the localization of the BaM between the conductors, the non reciprocal effect improved with increasing conductor thickness as the interaction between the field lines created by the conductors and the magnetic film is then favored.

Bubbly Silicon: A New Mechanism for Solid Phase Crystallization of Amorphous Silicon

2009 ◽  
Author(s):  
Curtis Anderson ◽  
Lin Cui ◽  
Uwe Kortshagen
Keyword(s):  
Amorphous Silicon ◽  
Polycrystalline Silicon ◽  
Silicon Nanocrystals ◽  
Solid Phase ◽  
Amorphous Film ◽  
Silicon Films ◽  
Amorphous Films ◽  
Solid Phase Crystallization ◽  
Rapid Formation ◽  
Polycrystalline Silicon Films

This paper describes the rapid formation of polycrystalline silicon films through seeding with silicon nanocrystals. The incorporation of seed crystals into amorphous silicon films helps to eliminate the crystallization incubation time observed in non-seeded amorphous silicon films. Furthermore, the formation of several tens of nanometer in diameter voids is observed when cubic silicon nanocrystals with around 30 nm in size are embedded in the amorphous films. These voids move through the amorphous film with high velocity, pulling behind them a crystallized “tail.” This mechanism leads to rapid formation of polycrystalline films.

Copper-Enhanced Solid Phase Crystallization of Amorphous Silicon Films

1996 ◽  
Vol 424 ◽  
Author(s):  
Dong Kyun Sohn ◽  
Dae Gyu Moon ◽  
Byung Tae Ahn
Keyword(s):  
Solid Phase ◽  
Copper Ions ◽  
Crystallization Time ◽  
Solid Phase Crystallization ◽  
New Process ◽  
Low Temperature Crystallization ◽  
Amorphous Si ◽  
Si Films ◽  
Fractal Size ◽  
Temperature Crystallization

AbstractLow-temperature crystallization of amorphous Si (a-Si) films was investigated by adsorbing copper ions on the surface of the films. The copper ions were adsorbed by spincoating of Cu solution. This new process lowered the crystallization temperature and reduced crystallization time of a-Si films. For 1000 ppm solution, the a-Si film was partly crystallized down to 500°C in 20 h and almost completely crystallized at 530°C in 20 h. The adsorbed Cu on the surface acted as a seed of crystalline and caused fractal growth. The fractal size was varied from 10 to 200 prm, depending on the Cu concentration in solution. But the grain size of the films was about 400 nm, which was similar to that of intrinsic films crystallized at 600°C.

Film thickness effects in the Co–Si1−xGex solid phase reaction

1998 ◽  
Vol 84 (8) ◽  
pp. 4285-4291 ◽  
Author(s):  
B. I. Boyanov ◽  
P. T. Goeller ◽  
D. E. Sayers ◽  
R. J. Nemanich
Keyword(s):  
Film Thickness ◽  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction

scholarly journals Mathematical simulation of catalytic paste flow in a ram extruder

2004 ◽  
Vol 58 (9) ◽  
pp. 387-392
Author(s):  
A.V. Zhensa ◽  
V.V. Kostutchenko ◽  
I.A. Petropavlovskiy ◽  
V.A. Filippin ◽  
E.M. Koltsova
Keyword(s):  
Mathematical Model ◽  
Film Thickness ◽  
Volume Content ◽  
Solid Phase ◽  
Functional Dependencies ◽  
Plastic Strength ◽  
Dispersed Phases ◽  
The Mathematical Model

A mathematical model was developed for the stage of catalyst paste preparation. The mathematical model allows the calculation of solvate film thickness and volume content of the solid phase at any moment of time. Functional dependencies were found, which correlated the solvate film thickness and volume content of the solid phase with the plastic strength and viscosity of catalyst pastes. A range of plastic strength was determined, which ensures the optimum forming properties of the pastes. The mathematical model allowed the determination of the concentrations of the components of the continuous and dispersed phases, which ensured the optimum paste forming rheological properties, which, in turn, influence the end properties of an a-FezOs catalyst. The significant role of the solvate film thickness in the forming properties of pastes was demonstrated.

Headspace Solid Phase Microextraction Procedure for the Detection of Polychlorinated Biphenyls in Seawater Sample

2013 ◽  
Vol 316-317 ◽  
pp. 383-386
Author(s):  
Xian Yin Ping ◽  
Yun Long Wang
Keyword(s):  
Polychlorinated Biphenyls ◽  
Film Thickness ◽  
Solid Phase Microextraction ◽  
Extraction Efficiency ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Headspace Solid Phase Microextraction ◽  
Relative Standard ◽  
Seawater Samples

Headspace solid phase microextraction combined with gas chromatography (HS-SPME–GC) method has been studied for determination of 7 polychlorinated biphenyls (PCBs) in seawater samples. To perform the HS-SPME polydimethylsiloxane (PDMS) (7, 30 and 100 µm film thickness) fibers were compared on the basis of their absorption capacities for the selected compounds, and PDMS 100 µm film thickness was selected. The influence of various parameters on PCBs extraction efficiency by HS-SPME was studied using GC-electron capture detector (ECD) compared with solid phase. The performance of proposed HS-SPME–GC methodology with respect to linearity, reproducibility and limit of detection (LOD) was evaluated by water spiked with target compounds. The linear range of most compounds was found to be between 0.1 and 100 µgL−1 and the limits of detection were between 15.2 and 63.8 ngL−1. The reproducibility of the method (n = 6), expressed as relative standard deviation (RSD), was between 4 and 10%. Finally, developed procedure was applied to determine selected PCBs in seawater samples.

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