Evidence against surface nucleation following pulsed melting of Si

1990 ◽  
Vol 5 (7) ◽  
pp. 1463-1467 ◽  
Author(s):  
P. S. Peercy ◽  
J. Y. Tsao ◽  
Michael O. Thompson
Keyword(s):  
Ion Implantation ◽  
Phase Formation ◽  
Ruby Laser ◽  
Laser Pulses ◽  
Time Dependent ◽  
Solidification Behavior ◽  
Rapid Melting ◽  
Surface Nucleation ◽  
Amorphous Si ◽  
Melting And Solidification

Time-dependent measurements of the melt and solidification behavior of amorphous Si, formed by ion implantation of In, have been obtained following irradiation with ∼3 ns ruby laser pulses. The recently observed buried In sheets formed under such conditions are shown to result from internal nucleation of melt, contrary to previous interpretations. Under no conditions was surface nucleation of either amorphous or crystalline Si observed from a surface melt. These results resolve previous inconsistencies in the understanding of phase formation during rapid melting and solidification of Si.

Surface Nucleation and Template Growth of Ti Silicides

1995 ◽  
Vol 402 ◽  
Author(s):  
R. T. Tung
Keyword(s):  
Low Temperature ◽  
Phase Formation ◽  
Nucleation And Growth ◽  
Silicide Phase ◽  
Formation Temperature ◽  
Low Resistivity ◽  
Surface Nucleation ◽  
Amorphous Si ◽  
Very Low Temperature

AbstractThe direct nucleation and growth of Ti silicide on the surfaces of Si(100) and amorphous Si were studied. Silicide phase formation depended on the temperature and the stoichiometry of deposition and the crystallinity of the substrate. A very low temperature, − 500°C, for the nucleation of the low-resistivity C54-TiSi2 phase was observed on amorphous Si. Stoichiometric and uniform TiSi2 layers were grown with the depositions of pure Ti. On crystalline Si, uniform TiSi2 layers were also grown at ∼ 500°C with a co-deposited template layer. The much reduced C54 formation temperature is discussed in terms of a possible circumvention of precursor amorphous silicide phases during surface nucleation.

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.

Kinetics of solid phase epitaxy in thick amorphous Si layers formed by MeV ion implantation

1990 ◽  
Vol 57 (13) ◽  
pp. 1340-1342 ◽  
Author(s):  
J. A. Roth ◽  
G. L. Olson ◽  
D. C. Jacobson ◽  
J. M. Poate
Keyword(s):  
Ion Implantation ◽  
Solid Phase ◽  
Solid Phase Epitaxy ◽  
Amorphous Si ◽  
Kinetics Of

Neutron Activation Measurements of As and Ga Loss During Transient Annealing of Gaas

1982 ◽  
Vol 13 ◽  
Author(s):  
A. Rose ◽  
J.T.A. Pollock ◽  
M.D. Scott ◽  
F.M. Adams ◽  
J.S. Williams ◽  
...  
Keyword(s):  
Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
Surface Temperature ◽  
Laser Power ◽  
Ruby Laser ◽  
Laser Pulses ◽  
Vitreous Carbon ◽  
Incoherent Light ◽  
Transient Conditions

ABSTRACTSignificant dissociation is normally detected under non-optimised transient annealing of GaAs. We have utilised neutron activation to measure As and Ga loss from virgin and implanted material annealed under various transient conditions. Complementary RBS data are reported. In particular, surface dissociation has been measured as a function of pulsed ruby laser power and for several combinations of time and surface temperature using an incoherent light source and a vitreous carbon strip heater.The results indicate that neutron activation analysis offers a powerful tool to identify the conditions required to minimise GaAs dissociation during annealing. For examplq ruby laser pulses of energy 0.29–1.38 J cm−2 caused As loss of 4 – 90 × 10 cm−2.

Pulsed Laser Treatment of Virgin, Self and Europium Implanted Nickel: Evidence of Defect Impurity Interaction

1981 ◽  
Vol 7 ◽  
Author(s):  
G. Battaglin ◽  
A. Carnera ◽  
G. Della Mea ◽  
P. Mazzoldi ◽  
Animesh K. Jain ◽  
...  
Keyword(s):  
Solid Solution ◽  
Liquid Phase ◽  
Laser Treatment ◽  
Ruby Laser ◽  
Pulsed Laser ◽  
Laser Pulses ◽  
Metastable Solid Solution ◽  
Ion Channeling ◽  
Impurity Interaction ◽  
The Eu

ABSTRACTWe present a comparative study (by 1.8 MeV 4He+ ion channeling) of virgin, self and Eu implanted single crystals of nickel, under irradiation with single ruby laser pulses. The as implanted Eu is nearly non-substitutional and remains so, even after laser treatment. The comparative defect dechanneling behaviour provides explicit evidence of defect-impurity interaction which may be suppressing the formation of an expected metastable solid solution in the Eu-Ni system, which possesses miscibility in the liquid phase. A clear surface Eu peak appears at 2.1 J/cm2.

Fourier-Bessel Series Model for the Stefan Problem With Internal Heat Generation in Cylindrical Coordinates

2018 ◽  
Author(s):  
Lyudmyla Barannyk ◽  
John Crepeau ◽  
Patrick Paulus ◽  
Ali Siahpush
Keyword(s):  
Differential Equation ◽  
Steady State ◽  
Heat Generation ◽  
Numerical Solutions ◽  
Internal Heat ◽  
Internal Heat Generation ◽  
Time Dependent ◽  
Cylindrical Coordinates ◽  
System Approaches ◽  
Melting And Solidification

A nonlinear, first-order ordinary differential equation that involves Fourier-Bessel series terms has been derived to model the time-dependent motion of the solid-liquid interface during melting and solidification of a material with constant internal heat generation in cylindrical coordinates. The model is valid for all Stefan numbers. One of the primary applications of this problem is for a nuclear fuel rod during meltdown. The numerical solutions to this differential equation are compared to the solutions of a previously derived model that was based on the quasi-steady approximation, which is valid only for Stefan numbers less than one. The model presented in this paper contains exponentially decaying terms in the form of Fourier-Bessel series for the temperature gradients in both the solid and liquid phases. The agreement between the two models is excellent in the low Stefan number regime. For higher Stefan numbers, where the quasi-steady model is not accurate, the new model differs from the approximate model since it incorporates the time-dependent terms for small times, and as the system approaches steady-state, the curves converge. At higher Stefan numbers, the system approaches steady-state faster than for lower Stefan numbers. During the transient process for both melting and solidification, the temperature profiles become parabolic.

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