On The Mechanism of Nucleation in Pulsed-laser Quenched Si Films on SiO2

2010 ◽  
Vol 1245 ◽  
Author(s):  
Yikang Deng ◽  
Qiongying Hu ◽  
Ui-Jin Chung ◽  
Adrian Chitu ◽  
Alexander Limanov ◽  
...  
Keyword(s):  
Computational Analysis ◽  
Pulsed Laser ◽  
Nucleation Mechanism ◽  
Si Films ◽  
Experimental Findings ◽  
Solid Nucleation

AbstractWe have investigated the solid nucleation mechanism in laser-quenched Si films on SiO2. Previously neglected experimental steps, consisting of BHF-etching and irradiation in vacuum, were implemented to reduce potential extrinsic influences. The resulting experimental findings and computational analysis lead us to conclude that solid nucleation consistently takes place heterogeneously at, and only at, the bottom liquid Si-SiO2 interface.

Excimer-Laser-Induced Melting and Solidification of PECVD a-Si films under Partial-Melting Conditions

2011 ◽  
Vol 1321 ◽  
Author(s):  
Q. Hu ◽  
Catherine S. Lee ◽  
T. Li ◽  
Y. Deng ◽  
U.J. Chung ◽  
...  
Keyword(s):  
Partial Melting ◽  
Pulsed Laser ◽  
Solidification Behavior ◽  
Fine Grained ◽  
Melting Regime ◽  
Si Films ◽  
Experimental Findings ◽  
Defective Crystal ◽  
Moving Liquid ◽  
Melting And Solidification

ABSTRACTThis paper reports on new experimental findings and conclusions regarding the pulsed-laser-induced melting-and-solidification behavior of PECVD a-Si films. The experimental findings reveal that, within the partial-melting regime, these a-Si films can melt and solidify in ways that are distinct from, and more complex than, those encountered in microcrystalline-cluster-rich LPCVD a-Si films. Specifically (1) spatially dispersed and temporally stochastic nucleation of crystalline solids occurring relatively effectively at the moving liquid-amorphous interface, (2) very defective crystal growth that leads to the formation of fine-grained Si proceeding, at least initially after the nucleation, at a sufficiently rapidly moving crystal solidification front, and (3) the propensity for local preferential remelting of the defective regions and grain boundaries (while the beam is still on) are identified as being some of the fundamental factors that can participate and affect how these PECVD films melt and solidify.

Luminescence hydrogenated nanoamorphous Si films fabricated by reactive pulsed laser ablation

2011 ◽  
Vol 176 (11) ◽  
pp. 835-839
Author(s):  
Wanbing Lu ◽  
Xingkuo Li ◽  
Xinzhan Wang ◽  
Liping Wu ◽  
Li Han ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Si Films

Patterned Structures of Silicon Nanocrystals Prepared by Pulsed Laser Interference Crystallization of Ultra-Thin A-Si:H Single-Layer

2002 ◽  
Vol 737 ◽  
Author(s):  
Xiaowei Wang ◽  
Feng Qiao ◽  
Leyi Zhu ◽  
Wei Li ◽  
Jian Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Crystalline Silicon ◽  
Pulsed Laser ◽  
Single Layer ◽  
Laser Interference ◽  
Raman Scattering Spectroscopy ◽  
Transmission Electron ◽  
Patterned Structures ◽  
Device Applications ◽  
Si Films

ABSTRACTWe employ the method of phase-modulated KrF excimer pulsed laser interference crystallization to fabricate nanometer-sized crystalline silicon (nc-Si) with the two-dimensional (2D) patterned distribution within the ultra-thin a-Si:H single-layer. The local crystallization occurs after interference laser irradiation under proper energy density. The results of atomic force microscopy, Raman scattering spectroscopy, cross-section transmission electron microscopy and scanning electron microscopy demonstrate that Si nano-crystallites are formed within the initial a-Si:H single-layer, selectively located in the discal regions with the diameter of 350 nm and patterned with the same 2D periodicity of 2.0 μm as the phase-shifting grating. The results show that the present method can be used to fabricate patterned nc-Si films for device applications.

Low Temperature Epitaxy of Si on Dihydride-Terminated Si (001): Energetic Versus Thermal Growth

1996 ◽  
Vol 441 ◽  
Author(s):  
M. E. Taylor ◽  
Harry A. Atwater ◽  
M. V. Ramana Murty
Keyword(s):  
Molecular Beam Epitaxy ◽  
Pulsed Laser Deposition ◽  
Molecular Beam ◽  
Pulsed Laser ◽  
High Energy ◽  
Interface Roughness ◽  
Laser Deposition ◽  
Cross Sectional ◽  
Comparison Of The Results ◽  
Si Films

AbstractPulsed laser deposition of Si on dihydride-terminated (l×1) Si (001) at low temperatures yields epitaxial layers, unlike molecular beam epitaxy. Si films were grown by ultrahigh vacuum pulsed laser deposition on the dihydride surface at substrate temperatures from 40 °C to 350 ° C. Epitaxial thickness and interface roughness were measured by high-resolution cross-sectional transmission electron microscopy and found to be comparable to known data for Si films grown by molecular beam epitaxy on monohydride-terminated (2×l) Si (001). Si films were grown at 200 °C by pulsed laser deposition on the dihydride surface at argon background pressures between 10− torr and 10−1 torr. Ion probe time of flight data was collected over the same pressure range. Comparison of the results suggests that loss of epitaxy is correlated with low incident energy. This, in conjunction with information on surface reconstruction obtained from reflection high-energy electron diffraction, suggests that the mechanism enabling epitaxy on the dihydride surface is Si subplantation, a mechanism only possible in growth with an energetic beam.

Pulsed Laser-Induced Crystallization and Amorphization of SiGe Films.

1992 ◽  
Vol 258 ◽  
Author(s):  
T. Sameshima ◽  
S. Usui
Keyword(s):  
Electrical Conductivity ◽  
Band Gap ◽  
Silicon Germanium ◽  
Carrier Mobility ◽  
Pulsed Laser ◽  
Nucleation Density ◽  
High Electrical Conductivity ◽  
Germanium Alloy ◽  
Si Films ◽  
Induced Crystallization

ABSTRACTPulsed laser-induced melting followed by crystallization and amorphization were studied on silicon-germanium alloy (SiGe) films. Although amorphization was achieved on SiGe films, it was not observed in pure Ge films. Crystalline nucleation density in homogeneous solidification increased as Ge concentration increased. It was 1×1024m-3for Si0.22Ge0.78 films, while it was 4×1022m-3 for pUre si films. Electrical conductivity of laser polycrystallized films increased as Ge concentration increased. It had a maximum of 1 S/cm when Ge concentration was 0.78. This high electrical conductivity would be brought about by the increase of carrier mobility as well as the reduction of the band gap.

scholarly journals Interface Velocity Transients During Melting of a-Si/C-Si Thin Films

1988 ◽  
Vol 100 ◽  
Author(s):  
J. Y. Tsao ◽  
M. J. Aziz ◽  
P. S. Peercy ◽  
M. O. Thompson
Keyword(s):  
Thin Films ◽  
Steady State ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Interface Temperature ◽  
Laser Melting ◽  
Systematic Procedure ◽  
Solid Interface ◽  
Amorphous Si ◽  
Si Films

ABSTRACTWe report transient conductance measurements of liquid/solid interface velocities during pulsed laser melting of amorphous Si (a-Si) films on crystalline Si (c-Si), and a more accurate, systematic procedure for analyzing these measurements than described in previous work [1]. From these analyses are extracted relations between the melting velocities of a-Si and c-Si at a given interface temperature, and between the temperatures during steady-state melting of a-Si and c-Si at a given interface velocity.

Annealing of GaN/ZnO/Si Films Deposited by Pulsed Laser Deposition

2007 ◽  
Vol 46 (2) ◽  
pp. 526-529 ◽  
Author(s):  
Cheng Yang ◽  
Baoyuan Man ◽  
Huizhao Zhuang ◽  
Xianqi Wei ◽  
Mei Liu ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Si Films
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