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.

The Crystallization and Amorphization of Si from the Melt at Interface Velocities Approaching 20 m/sec

1981 ◽  
Vol 4 ◽  
Author(s):  
J. M. Poate
Keyword(s):  
Heat Flow ◽  
Amorphous Phase ◽  
Interface Velocity ◽  
Solidification Velocity ◽  
Laser Melting ◽  
Substrate Orientation ◽  
Significant Lowering ◽  
Solid Interface ◽  
Amorphous Si

ABSTRACTLaser melting has been used to controllably vary the Si solidification velocity in the range 1–20 m/sec. The segregation of implanted impurities is found to be critically dependent on the liquid-solid interface velocity and substrate orientation for velocities <10 m/sec. This behavior can be understood in terms of different degrees of undercooling of the melt. While the (100) epitaxy is generally excellent up to velocities ∼10 m/sec, twins are observed for (111) epitaxy in the range ∼5–10 m/sec. Amorphous Si is produced from the melt for velocities in the vicinity of 20 m/sec. The amorphous phase forms at lower velocities on the (111) interface than on the (100) interface. These estimates of interface velocities come from heat flow calculations which do not include undercooling of the melt. Undercooling does not affect interface velocities ∼3 m/sec but significant lowering of the higher velocities could result from such effects.

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.

Congruent Melting Temperatures of Si-As Alloys Measured During Pulsed-Laser Melting and Rapid Solidification

1992 ◽  
Vol 279 ◽  
Author(s):  
J. A. Kittl ◽  
R. Reitano ◽  
M. J. Aziz ◽  
D. P. Brunco ◽  
M. O. Thompson
Keyword(s):  
Partition Coefficient ◽  
Temperature Measurement ◽  
Rutherford Backscattering Spectrometry ◽  
Pulsed Laser ◽  
Heat Of Fusion ◽  
Interface Temperature ◽  
Congruent Melting ◽  
Laser Melting ◽  
Time Resolved ◽  
Melting Temperatures

ABSTRACTThe solidification of Si-As alloys induced by pulsed laser melting was studied at regrowth velocities where the partition coefficient is close to unity. The congruent melting temperatures, TO, of Si-As alloys were determined using a temperature measurement technique developed for this work, and were confirmed with TOmeasurements using three other methods. The time-resolved temperature measurement uses a thin-film platinum thermistor, below and electrically isolated from the Si-As alloy layer, to directly measure the temperature during solidification. This, combined with measurements of transient conductance of the Si-As alloy, time-resolved reflectivity and Rutherford Backscattering Spectrometry, permitted the determination of the solid-liquid interface temperature, velocity and partition coefficient, the latent heat of fusion and TO for Si - 4.5 at. % As and Si - 9 at. % As alloys.

scholarly journals Synthesis of GaNxAs1−x thin films by pulsed laser melting and rapid thermal annealing of N+-implanted GaAs

2003 ◽  
Vol 94 (2) ◽  
pp. 1043-1049 ◽  
Author(s):  
K. M. Yu ◽  
W. Walukiewicz ◽  
M. A. Scarpulla ◽  
O. D. Dubon ◽  
J. Wu ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Annealing ◽  
Rapid Thermal Annealing ◽  
Pulsed Laser ◽  
Laser Melting

Photoluminescence of Chemically Etched Polycrystalline and Amorphous Si Thin Films

1993 ◽  
Vol 298 ◽  
Author(s):  
A. J. Steckl ◽  
J. Xu ◽  
H. C. Mogul
Keyword(s):  
Thin Films ◽  
Strong Relationship ◽  
Porous Si ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Si ◽  
Si Films ◽  
Uv Excitation ◽  
Highly Porous ◽  
Stain Etching

AbstractSi thin films were deposited on quartz at temperatures ( TD ) ranging from 540 to 640°C. X-ray diffraction indicates that films deposited at TD < 580°C are amorphous, while those deposited above 600°C are poly-crystalline with a <220> texture. The Si films were made porous by stain-etching in HF:HNO3:H2O. Only Si films deposited at 590°C and above show photoluminescence (PL), centered at ∼650-670 nm under UV excitation. Films deposited at TD < 580°C do not luminesce even after very long etch times, which produce a highly porous structure. The PL intensity and the x-ray signal follow a very similar trend with TD. It appears that a minimum level of crystallinity is required for photoemission in porous Si and that a strong relationship exists between them.

A Study on the Metal Induced Lateral Crystallization Behavior of Amorphous Silicon Thin Films

1996 ◽  
Vol 441 ◽  
Author(s):  
Byung-Il Lee ◽  
Kwang-Ho Kim ◽  
Won-Cheol Jeong ◽  
Pyung-Su Ahn ◽  
Jin-Wook Shin ◽  
...  
Keyword(s):  
Thin Films ◽  
Amorphous Silicon ◽  
Crystallization Behavior ◽  
Crystallization Rate ◽  
External Stress ◽  
Tem Analysis ◽  
Silicon Thin Films ◽  
Amorphous Si ◽  
Lateral Crystallization ◽  
Si Films

AbstractBasic mechanisms for both Ni- and Pd-metal induced lateral crystallization (MILC) are investigated. For both cases, tiny silicides were formed under the metal deposited area, and propagated toward amorphous Si films leaving crystallized Si behind at temperatures as low as 500 °C. Ni-MILC was influenced by Pd such that the lateral crystallization rate was enhanced, and the temperature for the lateral crystallization was lowered to 450 °C. Through TEM analysis and external stress experiments, it was found that the enhancement of the lateral crystallization rate was closely related to the compressive stress generated by the formation of nearby Pd2Si.

The Melting of Amorphous Si

1985 ◽  
Vol 57 ◽  
Author(s):  
J. M. Poate ◽  
P. S. Peercy ◽  
M. O. Thompson
Keyword(s):  
Melting Temperature ◽  
Pulsed Laser ◽  
Laser Melting ◽  
First Order ◽  
Explosive Crystallization ◽  
Liquid Transition ◽  
Melting Transitions ◽  
Amorphous Si

AbstractThe prediction by Turnbull and his colleagues that amorphous Si and Ge undergo first order melting transitions at temperatures Taℓ substantially beneath the crystalline melting temperature Tcℓ has stimulated much work. Structural, calorimet:ic and transient conductance measurements show that, for Si, Tcℓ – Taℓ lies in the range 225–250°K. Studies of the pulsed laser melting of the Si amorphous-liquid transition have resulted in the following findings, an estimate of the undercooling rate of 15°K/m/sec, an understanding of the mechanism mediating explosive crystallization, the formation of internal melts and segregation of dopants at the liquid-amorphous interface.

Crystallization of Amorphous Si Thin Films Using a Viscous Ni Solution

2000 ◽  
Vol 621 ◽  
Author(s):  
Jin Hyung Ahn ◽  
Sung Chul Kim ◽  
Byung Tae Ahn
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Propylene Glycol ◽  
Crystallization Temperature ◽  
Spin Coating ◽  
Direct Contact ◽  
Viscous Solution ◽  
Amorphous Si ◽  
Si Films

ABSTRACTWe prepared a viscous Ni solution by dissolving NiCl2 in 1N HCl and mixing it with propylene glycol to control the amount of Ni on Si surface. A uniform film was formed after spin coating and oven dry. The a-Si films deposited by LPCVD with Si2H6 gas were crystallized more uniformly and more reproducibly. And the crystallization was enhanced from 600°C, 30h to 500°C, 10h. The surface roughness of poly-Si film crystallized with the viscous solution was much smaller than that of poly-Si film crystallized from Ni/Si direct contact. The TFT mobility was improved even though the crystallization temperature was much lower.

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