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.

Pulsed Laser Annealing of Aluminum

1980 ◽  
Vol 1 ◽  
Author(s):  
W. R. Wampler ◽  
D. M. Follstaedt ◽  
P. S. Peercy
Keyword(s):  
Single Crystal ◽  
Laser Irradiation ◽  
Reasonable Agreement ◽  
Ruby Laser ◽  
Laser Annealing ◽  
Ion Beam ◽  
Pulsed Laser ◽  
Nucleation Time ◽  
Pulsed Laser Annealing ◽  
Beam Analysis

ABSTRACTPulsed ruby laser irradiation of unimplanted single crystal and implanted polycrystalline Al has been studied with ion beam analysis and TEM. The results show that Al is melted to a depth of ∼ 0.9 μm with a 4.2 J/cm2 , 15 nsec pulse, and that vacancies are quenched into Al during resolidification. Diffusion of Zn in liquid Al is observed, and a melt time of ∼ 65 nsec is estimated for a 3.8 J/cm2, 30 nsec pulse. The observations are in reasonable agreement with calculations of sample temperature and melt times. We observe no precipitation of AlSb in liquid Al for Sbimplanted Al, and conclude that the nucleation time satisfies 50 nsec ≲ tnuc ≲ 200 nsec. We find no evidence for amorphous Al after irradiation of single crystal Al with energies ≳ 1.5 J/cm2.

Nucleation of Allotropic Phases During Pulsed Laser Annealing of Manganese

1985 ◽  
Vol 51 ◽  
Author(s):  
J. H. Perepezko ◽  
D. M. Follstaedt ◽  
P. S. Peercy
Keyword(s):  
Melting Point ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Nucleation Kinetics ◽  
Pulsed Heating ◽  
Pulsed Laser Annealing ◽  
Incident Laser Pulse ◽  
Δ Phase ◽  
Undercooled Melt

ABSTRACTManganese has four allotropes with an equilibrium melting point of the high temperature δ-phase at 1517 K and calculated metastable melting points for the ϒ, β and α phases at 1501 K, 1481 K and 1395 K, respectively. Our observations for Mn irradiated with a pulsed laser and supporting estimates of maximum allotropic transition rates indicate that transformations between allotropes are suppressed during heating with ~ 25 ns laser pulses, as well as during subsequent cooling. Upon pulsed heating of β-Mn to the melt threshold, the melt is undercooled 122 K below the δ-Mn melting point. For incident laser pulse energy densities near the melting threshold, resolidification involves regrowth of β-Mn from the substrate. At energy densities well above threshold, the ϒ-Mn phase forms by separate nucleation and growth from the undercooled melt, and is retained upon rapid solidification. From these results and analyses, we conclude that significant melt undercooling, which may exceed 100 K, can occur during pulsed laser melting of metallic crystals and that the resulting crystalline structure is determined by both thermodynamics and nucleation kinetics.

A Laser Triggered Self-Sustaining Metals-Compound Semiconductor Transition for AlSb

1981 ◽  
Vol 4 ◽  
Author(s):  
R. Andrew ◽  
L. Baufay ◽  
A. Pigeolet ◽  
L.D. Laude
Keyword(s):  
Laser Pulse ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Pulsed Laser Annealing ◽  
Short Laser Pulses ◽  
Thermally Triggered ◽  
Heat Of Transformation ◽  
Complete Transformation

ABSTRACTThe preparation of AlSb thin films by pulsed laser annealing of Al/Sb sandwiches is studied in order to resolve some past controversy about the temperature rise induced by the laser pulse. Using 1000 Ȧ thick two layer films supported by TEM grids, we investigate the energy threshold for complete transformation as a function of pulse duration from 15 nsec to 100 msec, and of ambient temperature from −100°C to 250°C.We thence calculate the temperature effect directly induced by the laser to be about 930°C, or approximately the melting point of the metals, whereas inert gas furnace anneals of comparable films show transformation at this temperature occuring only in about 100 sec. We discuss the isoenergetic nature of the system for short laser pulses and the role of the heat of transformation, and thus conclude that the reaction is thermally triggered by the laser pulse but is to some extent self-sustaining via the heat of transformation locally distributed. This model is also shown to have equal validity for the systems CdTe, CdSe and AlAs.

Time-Resolved Study of Silicon During Pulsed-Laser Annealing

1983 ◽  
Vol 13 ◽  
Author(s):  
B. C. Larson ◽  
C. W. White ◽  
T. S. Noggle ◽  
J. F. Barhorst ◽  
D. M. Mills
Keyword(s):  
Laser Annealing ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
High Energy ◽  
Temperature Gradients ◽  
Time Resolved ◽  
Synchrotron Source ◽  
Near Surface ◽  
Solid Interface ◽  
Pulsed Laser Annealing

ABSTRACTNear surface temperatures and temperature gradients have been studied in silicon during pulsed laser annealing. The investigation was carried out using nanosecond resolution x-ray diffraction measurements made at the Cornell High Energy Synchrotron Source. Thermal-induced-strain analyses of these real-time, extended Bragg scattering measurements have shown that the lattice temperature reached the melting point during 15 ns, 1.1–1.5 J/cm2 ruby laser pulses and that the temperature of the liquid-solid interface remained at that temperature throughout the high reflectivity phase, after which time the surface temperature subsided rapidly. The temperature gradients below the liquid-solid interface were found to be in the range of 107°C/cm.

scholarly journals Interface Stability During Rapid Directional Solidification

1990 ◽  
Vol 205 ◽  
Author(s):  
David E. Hoglund ◽  
Michael J. Aziz
Keyword(s):  
Electron Microscopy ◽  
Laser Annealing ◽  
Critical Concentration ◽  
Local Equilibrium ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Planar Interface ◽  
Pulsed Laser Annealing ◽  
Nonequilibrium Effects ◽  
Oscillatory Instabilities

AbstractAt the solidification velocities observed during pulsed laser annealing, the planar interface between solid and liquid is stabilized by capillarity and nonequilibrium effects such as solute trapping. We used Rutherford backscattering and electron microscopy to determine the nonequilibrium partition coefficient and critical concentration for breakdown of the planar interface as a function of interface velocity for Sn-implanted silicon. This allows us to test the applicability of the Mullins- Sekerka stability theory to interfaces not in local equilibrium and to test the Coriell-Sekerka and other theories for oscillatory instabilities.

Pulsed laser annealing of Sn-implanted Si single crystal

2004 ◽  
Vol 95 (5) ◽  
pp. 2331-2336 ◽  
Author(s):  
D. Klinger ◽  
J. Auleytner ◽  
D. Żymierska ◽  
B. Kozankiewicz ◽  
L. Nowicki ◽  
...  
Keyword(s):  
Single Crystal ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Pulsed Laser Annealing

Pulsed Laser Annealing of Silicon-Germanium Films

2002 ◽  
Vol 741 ◽  
Author(s):  
Sherif Sedky ◽  
Jeremy Schroeder ◽  
Timothy Sands ◽  
Roger Howe ◽  
Tsu-Jae King
Keyword(s):  
Surface Roughness ◽  
Silicon Germanium ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Chemical Vapor ◽  
Laser Pulses ◽  
Pulsed Laser Annealing ◽  
Pressure Chemical ◽  
Noticeable Reduction ◽  
Columnar Grain

ABSTRACTIn this work, we investigate the possibility of using pulsed laser annealing to locally tailor the physical properties of Si1-xGex (18% < × < 90%) prepared by low pressure chemical vapor deposition (LPCVD) at 400°C. Films which were amorphous as deposited showed, after laser annealing, strong {111} texture and a columnar grain microstructure and an average resistivity of 0.7 mΩ.cm. AFM showed that the first few laser pulses result in a noticeable reduction in surface roughness, which is proportional to the pulse energy. However, a large number of successive pulses dramatically increases the surface roughness.

scholarly journals Laser Induced Defects and Materials Interactions in the V-Si System

1980 ◽  
Vol 1 ◽  
Author(s):  
B. R. Appleton ◽  
B. Stritzker ◽  
C. W. White ◽  
J. Narayan ◽  
J. Fletcher ◽  
...  
Keyword(s):  
Single Crystals ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Rapid Quenching ◽  
Ion Scattering ◽  
Ion Channeling ◽  
Pulsed Laser Annealing ◽  
Composition And Structure ◽  
Induced Defects

ABSTRACTPulsed laser annealing has been evaluated as a technique for fabricating superconducting V3 Si from multilayer V-Si samples, and the nature of laser-induced defects in V3 Si single crystals has been examined. Correlated analyses by ion scattering, ion channeling, Tc measurements and TEM were used to examine the composition and structure of samples subjected to single and multiple laser pulses. It was observed that although the superconducting A15 phase could be formed by pulsed laser mixing, the associated rapid quenching effects introduced defects which were not completely removed by thermal annealing to 925 K for 1 hour. Ion channeling and TEM studies of V3 Si single crystals showed that pulsed laser irradiation caused microcracks to develop in the surface, probably from mechanical stresses induced by thermal gradients.

Pulsed laser annealing of zinc implanted GaAs

1978 ◽  
Vol 14 (4) ◽  
pp. 85 ◽  
Author(s):  
S.S. Kular ◽  
B.J. Sealy ◽  
K.G. Stephens ◽  
D.R. Chick ◽  
Q.V. Davis ◽  
...  
Keyword(s):  
Laser Annealing ◽  
Pulsed Laser ◽  
Pulsed Laser Annealing
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