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.

Pulsed Laser Annealing of R.F.Sputtered Amorphous Si : H.Films, Doped with Arsenic

1981 ◽  
Vol 4 ◽  
Author(s):  
E. Fogarassy ◽  
R. Stuck ◽  
M. Toulemonde ◽  
P. Siffert ◽  
J.F. Morhange ◽  
...  
Keyword(s):  
Ruby Laser ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Amorphous Layer ◽  
High Concentration ◽  
Topographic Analysis ◽  
Pulsed Laser Annealing ◽  
Residual Hydrogen ◽  
Silicon Target ◽  
Amorphous Si

Arsenic doped amorphous silicon layers have been deposited on silicon single crystals by R.F.cathodic sputtering of a silicon target in a reactive argon-hydrogen mixture, and annealed with a Q-switched Ruby laser. Topographic analysis of the irradiated layers has shown the formation of a crater, due to an evaporation effect of material which could be related to the presence of a high concentration of Ar in the amorphous layer. RBS and Raman Spectroscopy showed that the remaining layer is not recrystallised probably due to inhibition by the residual hydrogen. However, it was found that arsenic diffuses into the monocrystalline substrate by laser induced diffusion of dopant from the surface solid source, leading to the formation of good quality P-N junctions.

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.

Laser Quenching of Amorphous Si from the Melt Containing Dopants

1983 ◽  
Vol 23 ◽  
Author(s):  
S. U. Campisano ◽  
D. C. Jacobson ◽  
J. M. Poate ◽  
A. G. Cullis ◽  
N. G. Chew
Keyword(s):  
Laser Irradiation ◽  
Ruby Laser ◽  
Metal Layer ◽  
Amorphous Layer ◽  
Irradiation Condition ◽  
Uv Laser ◽  
Surface Layers ◽  
Interfacial Segregation ◽  
Amorphous Si ◽  
Amorphous Surface

ABSTRACTThe formation of amorphous Si by the quench of a thin surface layer melted by fast UV laser irradiation has been investigated. The starting (111) surface layers were either pure or doped with As, Bi, In and Te by implantation. The asimplanted samples were recrystallized by ruby laser irradiation resulting in surface accumulation of Bi,In and Te. For the same UV irradiation condition, the amorphous layer formed in As, Bi, In or Te doped Si is about twice the thickness of the amorphous layer formed on pure Si. In the presence of the surface accumulation of Bi, In or Te, the amorphization results in an inward segregation of the dopant. For In, a very thin metal layer ˜15Å thick, is formed 150Å beneath the amorphous surface. These results show that the amorphous-liquid interfacial segregation coefficients for Bi, In or Te are less than unity and that the amorphous solidification proceeds from the surface and bottom of the liquid layer.

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

Dynamics of Rapid Solidification in Silicon

1986 ◽  
Vol 74 ◽  
Author(s):  
P. S. Peercy ◽  
Michael O. Thompson ◽  
J. Y. Tsao
Keyword(s):  
Transition State ◽  
Large Deviations ◽  
Layer Thickness ◽  
Melting Temperature ◽  
Amorphous Layer ◽  
Fine Grained ◽  
Explosive Crystallization ◽  
Explosive Transformation ◽  
Amorphous Si ◽  
Moving Liquid

AbstractReal-time techniques were used to study rapid melt and solidification dynamics in silicon. In crystalline Si, the interface response function was characterized and found to be asymmetric for large deviations from the melting temperature, which will require reevaluation of conventional transition state treatments of melt and solidification. In amorphous Si, the mechanism of explosive crystallization was studied. The explosive transformation is mediated by a buried liquid layer, and detailed measurements have led to the suggestion that polycrystalline Si nucleates at the moving liquid-amorphous interface. For certain conditions, this process could yield fine-grained polycrystalline Si; for other conditions it permits epitaxial regrowth from the underlying crystalline Si for maximum melt thickness much less than the original amorphous layer thickness.

Melting of Ion Implanted and Relaxed Amorphous Silicon

1989 ◽  
Vol 157 ◽  
Author(s):  
M.G. Grimaldi ◽  
P. Baeri ◽  
G. Baratta
Keyword(s):  
Amorphous Silicon ◽  
Threshold Energy ◽  
Pulsed Laser ◽  
Amorphous Layer ◽  
Surface Melting ◽  
Time Resolved ◽  
The Difference ◽  
Pulsed Laser Irradiation ◽  
Ion Implanted

ABSTRACTThe difference in the melting temperature of ion implanted and relaxed amorphous silicon has been measured. Pulsed laser irradiation (λ=347 nm, τ=30 ns) has been used to induce surface melting in the amorphous layer and time resolved reflectivity to detect the melting onset. The threshold energy density for surface melting in the relaxed amorphous was found 15.9±.3% higher than that in the unrelaxed one. The estimate of the variation of the thermal parameters in amorphous silicon upon relaxation allowed a determination of ΔTM=45±10 K between relaxed and unrelaxed amorphous silicon.

Regrowth Rates of Amorphous Layers in Silicon-on-Sapphire Films

1985 ◽  
Vol 52 ◽  
Author(s):  
P. J. Timans ◽  
R. A. McMahon ◽  
H. Ahmed
Keyword(s):  
Refractive Index ◽  
Electron Beam ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Amorphous Layer ◽  
Heating Cycle ◽  
Isothermal Heating ◽  
Time Resolved ◽  
Infra Red ◽  
High Absorption

ABSTRACTThe rate and direction of regrowth of amorphous layers, created by self-implantation, in silicon-on-sapphire (SOS) have been studied using time resolved reflectivity (TRR) experiments performed simultaneously at two wavelengths. Regrowth of an amorphous layer towards the surface was observed in specimens implanted with 3.1015Si+/cm2 at 50keV and regrowth of a buried amorphous layer, from a surface seed towards the sapphire, was observed in specimens implanted with 1.1015Si+/cm2 at 175keV. Rapid isothermal heating to regrow the layers was performed in an electron beam annealing system. The combination of 514.5nm and 632.8nm wavelengths was found to be particularly useful for TRR studies since the high absorption in amorphous silicon, at the shorter wavelength, means that the TRR trace is not complicated by reflection from the silicon-sapphire interface until regrowth is nearly complete. The dual wavelength method removes ambiguity about the position of the amorphous to crystalline interface and the direction of regrowth. The temperature dependence of the refractive index of silicon leads to large changes in the reflectivity of SOS films as they are heated. The combination of regrowth rate observations and reflectivity measurements during heating has been used to characterize the isothermal heating cycle, avoiding the difficulties of using pyrometers operating at the useful near infra-red wavelengths, where sapphire is transparent.

The Transition Between Amorphous Regrowth and Explosive Crystallization

1986 ◽  
Vol 74 ◽  
Author(s):  
J. J. P. Bruines ◽  
R. P. M. van Hal ◽  
B. H. Koek ◽  
M. P. A. Viegers ◽  
H. M. J. Boots
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Temperature Distribution ◽  
Laser Pulses ◽  
Si Substrate ◽  
Time Resolved ◽  
Explosive Crystallization ◽  
Transmission Electron ◽  
Amorphous Si ◽  
Substrate Temperatures

AbstractThe transition between amorphous regrowth and explosive crystallization of a 220nm thick amorphous Si layer on a crystalline Si substrate has been studied using time-resolved reflectivity, transmission electron microscopy, and Rutherford backscattering spectroscopy. Upon irradiation by 7.5ns FWHM pulses from a frequency-doubled Nd:YAG laser, interferences in the reflectivity indicate growth of amorphous Si from the surface. The observation of a narrow Cu peak, buried below the surface, points towards solidification from both the rear and the front. Transmission electron microscopy studies revealed the occurrence of small patches of polycrystalline Si. The relative amount of this polycrystalline Si is increased by longer laser pulses, higher substrate temperatures, and thicker amorphous Si layers. The results are discussed in terms of the temperature distribution and the time available for the nucleation of polycrystalline Si at the liquid-solid interface.

Dynamics of Rapid Solidification in Silicon

1986 ◽  
Vol 80 ◽  
Author(s):  
P. S. Peercy ◽  
Michael O. Thompson ◽  
J. Y. Tsao
Keyword(s):  
Transition State ◽  
Large Deviations ◽  
Layer Thickness ◽  
Melting Temperature ◽  
Amorphous Layer ◽  
Fine Grained ◽  
Explosive Crystallization ◽  
Explosive Transformation ◽  
Amorphous Si ◽  
Moving Liquid

AbstractReal-time techniques were used to study rapid melt and solidification dynamics in silicon. In crystalline Si, the interface response function was characterized and found to be asymmetric for large deviations from the melting temperature, which will require reevaluation of conventional transition state treatments of melt and solidification. In amorphous Si, the mechanism of explosive crystallization was studied. The explosive transformation is mediated by a buried liquid layer, and detailed measurements have led to the suggestion that polycrystalline Si nucleates at the moving liquid-amorphous interface. For certain conditions, this process could yield fine-grained polycrystalline Si; for other conditions it permits epitaxial regrowth from the underlying crystalline Si for maximum melt thickness much less than the original amorphous layer thickness.

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