Effects of Arsenic Doping on the Solidification Dynamics of Pulsed-Laser-Melted Silicon

1984 ◽  
Vol 35 ◽  
Author(s):  
Michael O. Thompson ◽  
P. S. Peercy ◽  
J. Y. Tsao
Keyword(s):  
Melting Temperature ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Surface Melting ◽  
Normal Surface ◽  
Arsenic Doping ◽  
Solid Interface ◽  
Conductance Technique ◽  
Velocity Changes

ABSTRACTThe effects of arsenic doping on the solidification dynamics during pulsed melting of silicon have been studied using the transient conductance technique. At As concentrations below 1 at.%, the incorporation of As into the Si lattice results in negligible differences in the solidification dynamics. Between 2 and 7 at.% As, however, the interface velocity is dramatically modified as the liquid-solid interface crosses the As containing region. These velocity changes are consistent with a reduced melting temperature for Si-As alloys. For concentrations of 11 at.% As, the depression in the melting temperature is sufficient to allow the surface to solidify while considerable melt remains buried within the sample. At 16 at.%, the melting temperature is drastically reduced and internal nucleation of melt occurs prior to normal surface melting.

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.

Interfacial overheating during melting of Si at 190 m/s

1987 ◽  
Vol 2 (1) ◽  
pp. 91-95 ◽  
Author(s):  
J. Y. Tsao ◽  
P. S. Peercy ◽  
Michael O. Thompson
Keyword(s):  
Energy Balance ◽  
Real Time ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Laser Melting ◽  
Solid Interface ◽  
Upper Limit ◽  
Balance Analysis ◽  
Energy Balance Analysis ◽  
Kinetics Of

An upper limit is placed on the overheating at the liquid/solid interface during melting of (100) Si at high interface velocity. The limit is based on an energy-balance analysis of melt depths measured in real time during pulsed-laser melting of Si on sapphire. When combined with previous measurements of the freezing kinetics of Si, this limit indicates that the kinetics of melting and freezing are nonlinear, i.e., the undercooling required to freeze at modest (15 m/s) velocities is proportionately much greater than the overheating required to melt at high (190 m/s) velocities.

Pulsed Laser Melting: The Effect of Implanted Solutes on the Resolidification Velocity

1983 ◽  
Vol 23 ◽  
Author(s):  
G. J. Galvin ◽  
J. W. Mayer ◽  
P. S. Peercy
Keyword(s):  
Electrical Conductance ◽  
Pulsed Laser ◽  
Solute Concentration ◽  
Atomic Percent ◽  
Supersaturated Solution ◽  
Solidification Velocity ◽  
Laser Melting ◽  
Solid Interface ◽  
Solution Studies ◽  
Nonequilibrium Segregation

ABSTRACTTransient electrical conductance has been used to measure the resolidification velocity in silicon containing implanted solutes. Nonequilibrium segregation of the solutes occurs during the rapid resolidification following pulsed laser melting. The velocity of the liquid-solid interface is observed to depend on the type and concentration of the solute. A 25% reduction in solidification velocity is observed for an implanted indium concentration of three atomic percent. Implanted oxygen is also shown to reduce the solidification velocity. The dependence of the velocity on solute concentration impacts a variety of segregation, trapping and supersaturated solution studies.

scholarly journals Overheating In Silicon During Pulsed-Laser Irradiation?

1985 ◽  
Vol 51 ◽  
Author(s):  
B. C. Larson ◽  
J. Z. Tischler ◽  
D. M. Mills
Keyword(s):  
Laser Irradiation ◽  
Thermal Strain ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
High Energy ◽  
Time Resolved ◽  
Synchrotron Source ◽  
Zero Velocity ◽  
The Difference ◽  
Pulsed Laser Irradiation

ABSTRACTNanosecond resolution time-resolved x-ray diffraction measurements of thermal strain have been used to measure the interface temperatures in silicon during pulsed-laser irradiation. The pulsed-time-structure of the Cornell High Energy Synchrotron Source (CHESS) was used to measure the temperature of the liquid-solid interface of <111> silicon during melting with an interface velocity of 11 m/s, at a time of near zero velocity, and at a regrowth velocity of 6 m/s. The results of these measurements indicate 110 K difference between the temperature of the interface during melting and regrowth, and the measurement at zero velocity shows that most of the difference is associated with undercooling during the regrowth phase.

Crystal Face Dependent Melting of a Polycrystalline Iron Surface During 30 PS Laser Pulses

1990 ◽  
Vol 205 ◽  
Author(s):  
A. Vaterlaus ◽  
D. Guarisco ◽  
F. Meier
Keyword(s):  
Surface Structure ◽  
Melting Temperature ◽  
Laser Pulses ◽  
Surface Melting ◽  
Iron Surface ◽  
Crystal Face ◽  
Polycrystalline Iron ◽  
Short Laser Pulses

AbstractThe melting of a polycrystalline iron surface with short laser pulses induces a surface structure with an orientation and a morphology depending on the crystal face of the surface. Different crystal planes irradiated with the same laser pulses show different degrees of disorder. This points to a crystal face dependent surface melting temperature.

Transient Conductance Measurements During Pulsed Laser Annealing

1981 ◽  
Vol 4 ◽  
Author(s):  
M. O. Thompson ◽  
G. J. Galvin ◽  
J. W. Mayer ◽  
R. B. Hammond ◽  
N. Paulter ◽  
...  
Keyword(s):  
Single Crystal ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Laser Pulses ◽  
Molten Layer ◽  
Pulsed Laser Annealing ◽  
Complete Melting ◽  
Solid Liquid Interface ◽  
Solid Liquid

ABSTRACTMeasurements were made of the conductance of single crystal Au-doped Si and silicon-on-sapphire (SOS) during irradiation with 30 nsec ruby laser pulses. After the decay of the photoconductive response, the sample conductance is determined primarily by the thickness and conductivity of the molten layer. For the single crystal Au-doped Si, the solid-liquid interface velocity during recrystallization was determined from the current transient to be 2.5 m/sec for energy densities between 1.9 and 2.6 J/cm2, in close agreement with numerical simulations based on a thermal model of heat flow. SOS samples showed a strongly reduced photoconductive response, allowing the melt front to be observed also. For complete melting of a 0.4 μm Si layer, the regrowth velocity was 2.4 m/sec.

Thermodynamic and Kinetic Studies of Pulsed-Laser Annealing from Transient Conductivity Measurements

1984 ◽  
Vol 35 ◽  
Author(s):  
P.S. Peercy ◽  
Michael O. Thompson
Keyword(s):  
Melting Temperature ◽  
Silicon Germanium ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Kinetic Studies ◽  
Alloy System ◽  
Velocity Versus ◽  
Solidification Velocity ◽  
Molten Layer ◽  
Amorphous Si

ABSTRACTSimultaneous measurements of the transient conductance and time-dependent surface reflectance of the melt and solidification dynamics produced by pulsed laser irradiation of Si are reviewed. These measurements demonstrate that the melting temperature of amorphous Si is reduced 200 ± 50 K from that of crystalline Si and that explosive crystallization in amorphous Si is mediated by a thin (≤ 20 nm) molten layer that propagates at ~ 15 m/sec. Studies with 3.5 nsec pulses permit an estimate of the dependence of the solidification velocity on undercooling. Measurements of the effect of As impurities on the solidification velocity demonstrate that high As concentrations decrease the melting temperature of Si (~ 150 K for 7 at.%), which can result in surface nucleation to produce buried melts. Finally, the silicon-germanium alloy system is shown to be an ideal model system for the study of superheating and undercooling. The Si50Ge50 alloy closely models amorphous Si, and measurements of layered Si-Ge alloy structures indicate superheating up to 120 K without nucleation of internal melts. The change in melt velocity with superheating yields a velocity versus superheating of 17 ± 3 k/m/sec.

scholarly journals Fabrication of nano-sized grains by pulsed laser surface melting

2010 ◽  
Vol 43 (9) ◽  
pp. 095402 ◽  
Author(s):  
Chengtao Wang ◽  
Hong Zhou ◽  
Pengyu lin ◽  
Na Sun ◽  
Qingchen Guo ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Surface Melting ◽  
Laser Surface ◽  
Laser Surface Melting

Measurement Of Precipitate Nucleation Times In Molten Metals By Pulsed Surface Melting

1983 ◽  
Vol 28 ◽  
Author(s):  
D.M. Follstaedt ◽  
S.T. Picraux ◽  
P.S. Peercy ◽  
J.A. Knapp ◽  
W.R. Wampler
Keyword(s):  
Pulsed Laser ◽  
Surface Melting ◽  
Complex Structures ◽  
Molten Metals ◽  
Simple Cubic ◽  
Beam Surface ◽  
Thermal Histories ◽  
Time Required ◽  
Precipitate Nucleation ◽  
Melt Duration

ABSTRACTThe short melt duration resulting from pulsed laser and electron beam surface melting of ion-implanted metals has been used to measure precipitate nucleation times of compounds within the melt. We have examined the phases present in several alloy systems with TEM and used calculated thermal histories to place limits on the time required for nucleation of the following compounds: AlSb (5–25 ns), Al3Ni (≳ 750 ns)Al3Ni2 (≳ 950 ns) and AlNi (< 1000 ns), all in molten Al, and TiC (≲ 100 ns) in molten Fe. The compounds observed after our rapid solidification have relatively simple, cubic structures and melt congruently, while those predicted but not observed have more complex structures and decompose peritectically.

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