Transient nucleation and manipulation of nucleation sites in solid‐state crystallization ofa‐Si films

1994 ◽  
Vol 75 (6) ◽  
pp. 2884-2901 ◽  
Author(s):  
Hideya Kumomi ◽  
Takao Yonehara
Keyword(s):  
Solid State ◽  
Nucleation Sites ◽  
Transient Nucleation ◽  
Si Films

Manipulation of Nucleation Sites in Solid-State Crystallization of Amorphous Si Films

1990 ◽  
Vol 202 ◽  
Author(s):  
Hideya Kumomi ◽  
Takao Yonehara
Keyword(s):  
Solid State ◽  
Ion Implantation ◽  
Size Distribution ◽  
Narrow Size Distribution ◽  
Amorphous Films ◽  
Nucleation Sites ◽  
Preferential Nucleation ◽  
Amorphous Si ◽  
Si Films ◽  
Si Ion Implantation

ABSTRACTNucleation sites are manipulated in amorphous Si films to control grain location and the size distribution during the solid-state crystallization. The principle of the method is theoretically investigated. Nucleation is suppressed and the sites are periodically formed in the plane of amorphous films by 2-step Si ion implantation. Thermal annealing causes preferential nucleation of single nuclei at the artificial sites and they grow laterally in the film. Consequently, 3 μm large grains were arranged in a matrix with a narrow size distribution.

Polycrystalline Si Films Fabricated by Low Temperature Selective Nucleation and Solid Phase Epitaxy Process

1997 ◽  
Vol 485 ◽  
Author(s):  
Claudine M. Chen ◽  
Harry A. Atwater
Keyword(s):  
Thin Film ◽  
Grain Size ◽  
Crystal Growth ◽  
Incubation Time ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Grain Sizes ◽  
Random Nucleation ◽  
Nucleation Sites ◽  
Si Films

AbstractWith a selective nucleation and solid phase epitaxy (SNSPE) process, grain sizes of 10 μm have been achieved to date at 620°C in 100 nrm thick silicon films on amorphous SiO2, with potential for greater grain sizes. Selective nucleation occurs via a thin film reaction between a patterned array of 20 rnm thick indium islands which act as heterogeneous nucleation sites on the amorphous silicon starting material. Crystal growth proceeds by lateral solid phase epitaxy from the nucleation sites, during the incubation time for random nucleation. The largest achievable grain size by SNSPE is thus approximately the product of the incubation time and the solid phase epitaxy rate. Electronic dopants, such as B, P, and Al, are found to enhance the solid phase epitaxy rate and affect the nucleation rate.

On the role of diffusion in phase selection during reactions at interfaces

1992 ◽  
Vol 7 (2) ◽  
pp. 367-373 ◽  
Author(s):  
C.V. Thompson
Keyword(s):  
Solid State ◽  
Thermodynamic Analysis ◽  
Phase Formation ◽  
Phase Selection ◽  
Transient Nucleation ◽  
State Amorphization

It is argued that interdiffusion must precede nucleation of new phases during reactions at interfaces between compositionally different phases. The relative rates at which elemental components diffuse in the reacting phases control the sequence in which phases can form, and can also strongly affect the relative nucleation rates of alloy products, especially in the transient nucleation regime. While detailed predictions of the relative nucleation rates require usually unavailable knowledge of the energies of the relevant interfaces, in some cases, knowledge of the relevant diffusivities, along with a thermodynamic analysis, can lead to predictions of likely phase formation sequences. These concepts are used to explain the association of diffusional asymmetry with systems that undergo solid state amorphization, and to specify semiquantitatively the degree of asymmetry required for solid state amorphization.

Synthesis and Characterization of Solid-State Phase Change Material Microcapsules for Thermal Management Applications

2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Fangyu Cao ◽  
Jing Ye ◽  
Bao Yang
Keyword(s):  
Heat Capacity ◽  
Solid State ◽  
Phase Change ◽  
Thermal Management ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Silica Shell ◽  
Heat Transfer Fluid ◽  
Nucleation Sites

Polyalcohols such as neopentyl glycol (NPG) undergo solid-state crystal transformations that absorb/release significant latent heat. These solid–solid phase change materials (PCM) can be used in practical thermal management applications without concerns about liquid leakage and thermal expansion during phase transitions. In this paper, microcapsules of NPG encapsulated in silica shells were successfully synthesized with the use of emulsion techniques. The size of the microcapsules range from 0.2 to 4 μm, and the thickness of the silica shell is about 30 nm. It was found that the endothermic phase transition of these NPG-silica microcapsules was initiated at around 39 °C and the latent heat was about 96.0 J/g. A large supercooling of about 43.3 °C was observed in the pure NPG particles without shells, while the supercooling of the NPG microcapsules was reduced to about 14 °C due to the heterogeneous nucleation sites provided by the silica shell. These NPG microcapsules were added to the heat transfer fluid PAO to enhance its heat capacity and the effective heat capacity of the fluid was increased by 56% with the addition of 20 wt. % NPG-silica microcapsules.

Effect of the Crystallographic Orientation of Underlying Poly-Si on the Thermal Stability of the TiSi2 Film

1992 ◽  
Vol 280 ◽  
Author(s):  
Y. W. Kim ◽  
I. K. Kim ◽  
N. I. Lee ◽  
J. W. Ko ◽  
S. T. Ahn ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Solid State ◽  
Surface Energy ◽  
Microstructural Evolution ◽  
Solid State Reaction ◽  
Crystallographic Orientation ◽  
Amorphous Si ◽  
Si Films ◽  
Thermal Stability Of

ABSTRACTThe effect of the crystallographic orientation of underlying poly-Si film on the thermal stability of the TiSi2 film was studied. Different preferred orientations of the poly-Si film were obtained by annealing poly-Si or amorphous Si films at various temperatures. The TiSi2 film was formed by the solid-state reaction of the Ti film sputtered on the poly-Si film. The thermal stability of the TiSi2 film was evaluated by changes in the sheet resistance and microstructural evolution during furnace anneals. The TiSi2 film on poly-Si with the <110> preferred orientation shows more stable conductivity during high temperature anneals than with the <111> orientation. The surface energy of underlying poly-Si is expected to influence the thermal stability of the TiSi2/poly-Si structure significantly. Better thermal stability of the TiSi2 film can be obtained by the higher surface energy of underlying poly-Si.

A transient nucleation model for solid state amorphisation

1988 ◽  
Vol 6 (11-12) ◽  
pp. 401-405 ◽  
Author(s):  
R.J. Highmore ◽  
A.L. Greer ◽  
J.A. Leake ◽  
J.E. Evetts
Keyword(s):  
Solid State ◽  
Nucleation Model ◽  
Transient Nucleation

scholarly journals An Endocytic Capture Model for Skeletal Muscle T-tubule Formation

2020 ◽  
Author(s):  
Thomas E Hall ◽  
Nick Martel ◽  
Nicholas Ariotti ◽  
Zherui Xiong ◽  
Harriet P Lo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Three Dimensional ◽  
Quantitative Model ◽  
Membrane Domain ◽  
Recycling Endosome ◽  
Tubule Formation ◽  
Rab Protein ◽  
Nucleation Sites ◽  
Transient Nucleation

AbstractThe skeletal muscle T-tubule is a specialized membrane domain essential for coordinated muscle contraction that shows dysmorphology in a number of genetically inherited muscle diseases. However, in the absence of genetically tractable systems the mechanisms involved in T-tubule formation are unknown. Here, we have used the optically transparent and genetically tractable zebrafish system to probe T-tubule development in vivo. By combining live imaging with three-dimensional electron microscopy we derived a four-dimensional quantitative model for T-tubule formation. To elucidate the mechanisms involved in T-tubule formation in vivo we developed a quantitative screen for proteins that associate with and modulate early T-tubule formation including an overexpression screen of the entire zebrafish Rab protein family. We propose a new endocytic capture model involving i) formation of dynamic endocytic tubules at transient nucleation sites on the sarcolemma ii) stabilization by myofibrils/sarcoplasmic reticulum and iii) delivery of membrane from the recycling endosome and Golgi complex.

Crystal forms by solid‐state recrystallization of amorphous Si films on SiO2

1991 ◽  
Vol 59 (6) ◽  
pp. 653-655 ◽  
Author(s):  
T. Noma ◽  
T. Yonehara ◽  
H. Kumomi
Keyword(s):  
Solid State ◽  
Crystal Forms ◽  
Amorphous Si ◽  
Si Films ◽  
Solid State Recrystallization

Improvement of Grain Size by Crystallization of Double-Layer Amorphous Silicon Films

1994 ◽  
Vol 345 ◽  
Author(s):  
Dae Gyu Moon ◽  
Jeong No Lee ◽  
Ho Bin Im ◽  
Byung Tae Ahn ◽  
Kee Soo Nam ◽  
...  
Keyword(s):  
Grain Size ◽  
Double Layer ◽  
Nucleation Rate ◽  
Incubation Time ◽  
Deposition Temperature ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Double Layers ◽  
Nucleation Sites ◽  
Si Films

AbstractWe investigated the solid phase crystallization (SPC) behavior of 1000 Å amorphous Si (a- Si) films deposited by plasma enhanced chemical vapor deposition (PECVD) at various temperatures and were able to enhance the grain size of the crystallized polysilicon films using double layers of a-Si filns. The deposition temperature of monolayer a-Si films varied from 200 to 400 °C and the films were recrystallized at 600 °C in nitrogen. As the deposition temperature increased, the incubation time was decreased and both the nucleation rate and growth rate were increased. Especially, the nucleation rate strongly depended on the deposition temperature.Since the Si-SiO2 interface provides a large number of nucleation sites, it is desirable to suppress nucleation at the interface. As an idea we employed a structure with double layer a-Si films. The bottom a-Si layer deposited at lower temperature could suppress the nucleation at the Si-SiO2 interface while the top a-Si layer deposited at higher temperature could nucleate with a smaller number of nucleation sites. The incubation time and transformation behavior were determined by the deposition temperature of the top layer. As an example, the grain size of the double layer film deposited sequentially at 150 °C and 200 °C enhanced to 1.8 μm while that of the monolayer film deposited at 200 °C was 1.4 μm.

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