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.

Optical and electrical correlation effects in ZnO nanostructures: Role of pulsed laser annealing

2021 ◽  
Vol 115 ◽  
pp. 111028
Author(s):  
Hayder J. Al-Asedy ◽  
Shuruq A. Al-khafaji ◽  
S.K. Ghoshal
Keyword(s):  
Laser Annealing ◽  
Pulsed Laser ◽  
Zno Nanostructures ◽  
Correlation Effects ◽  
Pulsed Laser Annealing

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.

Raman and Optical Properties of the Pulsed Laser Annealing Phase of SI

1981 ◽  
Vol 4 ◽  
Author(s):  
A. Compaan ◽  
A. Aydinli ◽  
M. C. Lee ◽  
H. W. LO
Keyword(s):  
Optical Properties ◽  
Laser Pulse ◽  
Absorption Coefficient ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Experimental Tests ◽  
Small Temperature ◽  
Pulsed Laser Annealing ◽  
Near Ir ◽  
Transmission Measurements

ABSTRACTRaman measurements of temperature reported earlier have been repeated using a doubled Nd: YAG pulse for excitation and an electronically delayed dye laser pulse. These results, together with a variety of experimental tests of the Raman method, confirm the validity of the small temperature rise during pulsed laser annealing. Transmission measurements spanning the visible and near IR show that there exists a thin (∼ 70 nm) layer at the surface in which the induced absorption coefficient is ∼ 7 × 105 cm−1.

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.

Raman Studies of Carrier Activation in Laser Annealed GaAs Capped with Silicon Nitride

1986 ◽  
Vol 74 ◽  
Author(s):  
A. Compaan ◽  
S. C. Abbi ◽  
H. D. Yao ◽  
A. Bhat ◽  
F. Hashmi
Keyword(s):  
Silicon Nitride ◽  
Laser Pulse ◽  
Raman Scattering ◽  
Excimer Laser ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Dye Laser ◽  
Pulsed Laser Annealing ◽  
Wide Range ◽  
Xecl Excimer Laser

AbstractCarrier concentrations exceeding 1019/cm3 in GaAs implanted with Si (2 × 1014/cm2 @ 140 keV) have been obtained by pulsed laser annealing with either a dye laser (λ = 728 nm) or a XeCl excimer laser (λ = 308 nm). Carrier concentrations were measured by plasmon Raman scattering over a wide range of anneal energy densities. Compared with capless laser annealing, much higher carrier activations were achieved when the annealing laser pulse was incident through a Si3N4 cap.

Faster Quenching by Silicon Pulsed Laser Annealing Under Water

1986 ◽  
Vol 74 ◽  
Author(s):  
A. Polman ◽  
S. Roorda ◽  
S. B. Ogale ◽  
F. W. Saris
Keyword(s):  
Laser Pulse ◽  
Laser Annealing ◽  
Crystalline Silicon ◽  
Diffusion Theory ◽  
Pulsed Laser ◽  
Silicon Layer ◽  
Water Layer ◽  
Amorphous Layer ◽  
Pulsed Laser Annealing ◽  
Novel Method

AbstractA novel method of pulsed laser processing of ion-implanted silicon is presented, in which samples are irradiated in water ambient. The water layer in contact with the silicon during irradiationh as a considerable influence on melting and solidificationd ynamics. Still, perfect epitaxy of a thin amorphous layer can be obtained using this method.For epitaxy to occur on a sample irradiated under water, 40 % more absorbed energy is necessary than for a sample irradiated in air. This indicates the occurrence of a considerable heat-flow from the silicon into the water layer during the laser pulse. From impurity redistribution after irradiation it is found that by processing a sample under water liquid-phase diffusion is reduced. Diffusion theory arguments indicate that this can be due to a reduction in total melt duration by about afactor 2–3. This can be due to faster cooling of the liquid silicon layer after the laser pulse whereas the melt-in time might be influenced as well. As a consequence, shallower impurity profiles can be obtained in crystalline silicon. No oxygen incorporation is detected and the surface morphology is not disturbed using this new process.

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.

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.

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