Time‐resolved reflectivity measurements during explosive crystallization of amorphous silicon

1986 ◽  
Vol 49 (18) ◽  
pp. 1160-1162 ◽  
Author(s):  
J. J. P. Bruines ◽  
R. P. M. van Hal ◽  
H. M. J. Boots ◽  
A. Polman ◽  
F. W. Saris
Keyword(s):  
Amorphous Silicon ◽  
Time Resolved ◽  
Explosive Crystallization

Excimer Laser Amorphous Silicon Film Crystallization: A Study of Time Resolved Reflectivity Measurements

1993 ◽  
Vol 297 ◽  
Author(s):  
C. Summonte ◽  
M. Bianconi ◽  
D. Govoni
Keyword(s):  
Heat Flow ◽  
Amorphous Silicon ◽  
Silicon Film ◽  
Optical Simulation ◽  
Molten Layer ◽  
Time Resolved ◽  
Flow Calculation ◽  
Explosive Crystallization ◽  
Bulk Nucleation ◽  
Calculation Results

Time Resolved Reflectivity during XeCl pulsed laser irradiation of amorphous silicon films deposited on glass was measured. Simulation of the process by a Heat Flow Calculation in which explosive crystallization was not forced to occur, predicts the coexistence of partial bulk nucleation and a traveling molten layer. Optical simulation of Time Resolved Reflectivity was used to critically examine the Heat Flow Calculation results, substantially confirming the existence of a mixture of thermodynamical phases.

Epitaxial Explosive Crystallization of Amorphous Silicon Layers Buried in a Silicon (100) and (111) Matrix

1989 ◽  
Vol 147 ◽  
Author(s):  
P. A. Stolk ◽  
A. Polman ◽  
W. C. Sinke
Keyword(s):  
Amorphous Silicon ◽  
Cross Section ◽  
Ruby Laser ◽  
Crystallization Process ◽  
Amorphous Layer ◽  
High Density ◽  
Time Resolved ◽  
Explosive Crystallization ◽  
Amorphous Si ◽  
Twin Defects

Abstract420 nm thick amorphous Si layers buried in a Si (100) or Si (111) matrix, produced by 350 keV Si-implantation, were irradiated using a pulsed ruby laser. Time-resolved reflectivity measurements show that melting can be initiated buried in the samples at the crystalline-amorphous interface. Melting is immediately followed by explosive crystallization of the buried amorphous layer, which is started from the crystalline top layer. The velocity of this self-sustained crystallization process is determined to be 15.0 ± 0.5 m/s for Si (100) and 14.0 ± 0.5 m/s for Si (111). RBS and cross-section TEM reveal that epitaxially grown crystalline Si, containing a high density of twin defects, is formed in both the Si (100) and the Si (111) sample.

Freezing in Silicon at Large Undercooling

1989 ◽  
Vol 157 ◽  
Author(s):  
P.A. Stolk ◽  
A. Polman ◽  
W.C. Sinke
Keyword(s):  
Interface Temperature ◽  
Limiting Factor ◽  
Time Resolved ◽  
Large Undercooling ◽  
Explosive Crystallization ◽  
Crystallization Speed ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Rate Limiting

ABSTRACTPulsed laser irradiation is used to induce epitaxial explosive crystallization of amorphous silicon layers buried in a (100) oriented crystalline matrix. This process is mediated by a self-propagating liquid layer. Time-resolved determination of the crystallization speed combined with numerical calculation of the interface temperature shows that freezing in silicon saturates at 16 m/s for large undercooling (> 130 K). A comparison between data and different models for melting and freezing indicates that the crystallization behavior at large undercooling can be described correctly if the rate-limiting factor is assumed to be diffusion in liquid Si at the solid/liquid interface.

Solidification of highly undercooled liquid silicon produced by pulsed laser melting of ion-implanted amorphous silicon: Time-resolved and microstructural studies

1987 ◽  
Vol 2 (5) ◽  
pp. 648-680 ◽  
Author(s):  
D. H. Lowndes ◽  
S. J. Pennycook ◽  
G. E. Jellison ◽  
S. P. Withrow ◽  
D. N. Mashburn
Keyword(s):  
Pulsed Laser ◽  
Optical Measurements ◽  
Undercooled Liquid ◽  
Laser Melting ◽  
Time Resolved ◽  
Fine Grained ◽  
Explosive Crystallization ◽  
Epitaxial Regrowth ◽  
Surface Melt ◽  
Melt Duration

Nanosecond resolution time-resolved visible (632.8 nm) and infrared (1152 nm) reflectivity measurements, together with structural and Z-contrast transmission electron microscope (TEM) imaging, have been used to study pulsed laser melting and subsequent solidification of thick (190–410 nm) amorphous (a) Si layers produced by ion implantation. Melting was initiated using a KrF (248 nm) excimer laser of relatively long [45 ns full width half maximum (FWHM)] pulse duration; the microstructural and time-resolved measurements cover the entire energy density (E1) range from the onset of melting (at ∼ 0.12J/cm2) up to the onset of epitaxial regrowth (at ∼ 1.1 J/cm2). At low E1 the infrared reflectivity measurements were used to determine the time of formation, the velocity, and the final depth of “explosively” propagating buried liquid layers in 410 nm thick a-Si specimens that had been uniformly implanted with Si, Ge, or Cu over their upper ∼ 300 nm. Measured velocities lie in the 8–14 m/s range, with generally higher velocities obtained for the Ge- and Cu-implanted “a-Si alloys.” The velocity measurements result in an upper limit of 17 (± 3) K on the undercooling versus velocity relationship for an undercooled solidfying liquid-crystalline Si interface. The Z-contrast scanning TEM measurements of the final buried layer depth were in excellent agreement with the optical measurements. The TEM study also shows that the “fine-grained polycrystalline Si” region produced by explosive crystallization of a-Si actually contains large numbers of disk-shaped Si flakes that can be seen only in plan view. These Si flakes have highly amorphous centers and laterally increasing crystallinity; they apparently grow primarily in the lateral direction. Flakes having this structure were found both at the surface, at low laser E1, and also deep beneath the surface, throughout the “fine-grained poly-Si” region formed by explosive crystallization, at higher E1. Our conclusion that this region is partially amorphous (the centers of flakes) differs from earlier results. The combined structural and optical measurements suggest that Si flakes nucleate at the undercooled liquid-amorphous interface and are the crystallization events that initiate explosive crystallization. Time-resolved reflectivity measurements reveal that the surface melt duration of the 410 nm thick a-Si specimens increases rapidly for 0.3E1 <0.6 J/cm2, but then remains nearly constant for E1 up to ∼ 1.0 J/cm2. For 0.3 < E1 < 0.6 J/cm2 the reflectivity exhibits a slowly decaying behavior as the near-surface pool of liquid Si fills up with growing large grains of Si. For higher E1, a flat-topped reflectivity signal is obtained and the microstructural and optical studies together show that the principal process occurring is increasingly deep melting followed by more uniform regrowth of large grains back to the surface. However, cross-section TEM shows that a thin layer of fine-grained poly-Si still is formed deep beneath the surface for E1<0.9 J/cm2, implying that explosive crystallization occurs (probably early in the laser pulse) even at these high E1 values. The onset of epitaxial regrowth at E1 = 1.1 J/cm2 is marked by a slight decrease in surface melt duration.

Time-resolved reflectance studies of silicon during laser thermal processing of amorphous silicon gates on ultrathin gate oxides

2004 ◽  
Vol 95 (11) ◽  
pp. 6048-6053 ◽  
Author(s):  
Y. F. Chong ◽  
H.-J. L. Gossmann ◽  
M. O. Thompson ◽  
S. Yang ◽  
K. L. Pey ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Thermal Processing ◽  
Gate Oxides ◽  
Time Resolved ◽  
Laser Thermal Processing

Impurity segregation during explosive crystallization of amorphous silicon

1983 ◽  
Vol 54 (6) ◽  
pp. 3485-3488 ◽  
Author(s):  
D. Bensahel ◽  
G. Auvert ◽  
A. Perio ◽  
J. C. Pfister ◽  
A. Izrael ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Impurity Segregation ◽  
Explosive Crystallization

Time-resolved shear transformations in the transient plastic regime of sheared amorphous silicon

2020 ◽  
Vol 102 (5) ◽  
Author(s):  
Tristan Albaret ◽  
Francesca Boioli ◽  
David Rodney
Keyword(s):  
Amorphous Silicon ◽  
Time Resolved ◽  
Plastic Regime
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