Dopant Incorporation During Rapid Solidification

1982 ◽  
Vol 13 ◽  
Author(s):  
C. W. White ◽  
D. M. Zehner ◽  
J. Narayan ◽  
O. W. Holland ◽  
B. R. Appleton ◽  
...  
Keyword(s):  
Rapid Solidification ◽  
Growth Velocity ◽  
Crystal Orientation ◽  
Laser Annealing ◽  
Distribution Coefficients ◽  
Solute Trapping ◽  
Group Iii ◽  
Dopant Incorporation ◽  
High Concentrations

ABSTRACTIncorporation of Group III, IV, V dopants in silicon occurs as a result of solute trapping during laser annealing. Distribution coefficients and substitutional solubilities are far greater than equilibrium values, and can be functions of growth velocity and crystal orientation. Mechanisms limiting dopant incorporation at high concentrations are identified and discussed.

Development of Morphological Instability and Cells During Rapid Solidification of Laser Annealed Silicon Alloys

1981 ◽  
Vol 8 ◽  
Author(s):  
J. Narayan ◽  
C. W. White
Keyword(s):  
Rapid Solidification ◽  
Laser Annealing ◽  
Cell Formation ◽  
Solute Concentration ◽  
Distribution Coefficients ◽  
Morphological Instability ◽  
Silicon Alloys ◽  
Plan View ◽  
Average Cell ◽  
Pulsed Laser Annealing

ABSTRACTThe details of morphological instability occurring during rapid solidification have been studied in In+, Ga+, Sb+, Bi+, Ge+, Fe+ and Cr+ implanted silicon specimens after pulsed laser annealing. The average cell sizes were determined at the onset of instability and in the region of well-developed instability using x-section and plan-view electron microscopy. The total and substitutional solute concentration profiles were determined using Rutherford backscattering and channeling techniques. The formation of cells and the critical solute concentrations associated with instability were studied as a function of velocity of solidification, which was varied by controlling the substrate temperature or the laser parameters. The results on the cell formation and the critical solute concentrations were compared with the predictions of the perturbation theory which took into account the dependence of distribution coefficients on the velocity of solidification. A good agreement between the calculations and the experimental results was obtained. We also examined theoretically the effect of reduction in surface tension due to segregation of impurities on cell sizes and critical solute concentrations associated with instability.

Trends in Solute Segregation Behavior During Silicon Solidification

1993 ◽  
Vol 321 ◽  
Author(s):  
Riccardo Reitanot ◽  
Patrick M. Smith ◽  
Michael J. Aziz
Keyword(s):  
Crystal Growth ◽  
Inverse Correlation ◽  
High Growth ◽  
Orientation Dependence ◽  
Solute Trapping ◽  
Group Iii ◽  
Explosive Crystallization ◽  
Crystallization Speed ◽  
Crystal Growth Kinetics ◽  
Interface Structures

ABSTRACTAt the high growth rates accessible during pulsed-laser induced melting and solidification and explosive crystallization, crystal growth kinetics are dominated not by equilibrium thermodynamics, but by the atomistic mechanisms by which crystallization proceeds. These Mechanisms can be probed by testing the predictions of solute trapping models based on various crystal/Melt interface structures against Measurements. We have measured the dependence of solute trapping of several group III, IV, and V elements in silicon on both interface orientation and crystallization speed. The Aperiodic Stepwise Growth Model of Goldman and Aziz accurately fits both the velocity and orientation dependence of the solute trapping observed in these systems. The success of the model implies a ledge structure for the crystal/Melt interface and a step-flow mechanism for crystal growth. In addition, we have observed an empirical inverse correlation between the two free parameters (“diffusive speeds”) in this model and the equilibrium solute partition coefficient of a system. This correlation may be used to estimate values of the diffusive speeds for other systems in which solute trapping has not been or cannot be Measured.

scholarly journals Solute trapping of group III, IV, and V elements in silicon by an aperiodic stepwise growth mechanism

1994 ◽  
Vol 76 (3) ◽  
pp. 1518-1529 ◽  
Author(s):  
Riccardo Reitano ◽  
Patrick M. Smith ◽  
Michael J. Aziz
Keyword(s):  
Growth Mechanism ◽  
Solute Trapping ◽  
Group Iii

scholarly journals Crystal Growth and Solute Trapping

1983 ◽  
Vol 23 ◽  
Author(s):  
Michael J. Aziz
Keyword(s):  
Free Energy ◽  
Steady State ◽  
Laser Annealing ◽  
Solute Drag ◽  
Irreversible Processes ◽  
Maximum Speed ◽  
Growth Speed ◽  
Solute Trapping ◽  
Order Of Magnitude ◽  
Energy Dissipated

ABSTRACTA simple model for solute trapping during rapid solidification is presented in terms of a single unknown parameter, the interfacial diffusivity Di. A transition from equilibrium segregation to complete solute trapping occurs over roughly an order of magnitude in growth speed, as the interface speed surpasses the maximum speed with which solute atoms can diffuse across the interface to remain ahead of the growing crystal. This diffusive speed is given by Di/λ, where λ is the interatomic spacing, and is typically of the order 10 meters per second. Comparison is made with experiment. The steady–state speed of a planar interface is predicted by calculating the free energy dissipated by irreversible processes at the interface and equating it to the available driving free energy. A solute drag term and an intrinsic interfacial mobility term are included in the dissipation calculations. Steady–state solutions are presented for Bi–doped Si during pulsed laser annealing.

Test of Kinetic Models for Interface Velocity, Temperature, and Solute Trapping in Rapid Solidification

1995 ◽  
Vol 398 ◽  
Author(s):  
J.A. Kittl ◽  
M.J. Aziz ◽  
D.P. Brunco ◽  
M.O. Thompson
Keyword(s):  
Rapid Solidification ◽  
Pulsed Laser ◽  
Interface Velocity ◽  
Alloy System ◽  
Solute Drag ◽  
Temperature Function ◽  
Continuous Growth ◽  
Solute Trapping ◽  
Interface Kinetics ◽  
Test Models

ABSTRACTDuring rapid solidification, deviations from local interfacial equilibrium are manifested by solute trapping and interfacial undercooling. Both the solute trapping function and the interface velocity-temperature function have been measured in the Si:As alloy system following pulsed laser melting, permitting us to test models for nonequilibrium interface kinetics. The results are consistent with the Continuous Growth Model “without solute drag” of Aziz and Kaplan and are inconsistent with models that incorporate solute drag effects during solidification.

Solute trapping and solute drag in a phase-field model of rapid solidification

1998 ◽  
Vol 58 (3) ◽  
pp. 3436-3450 ◽  
Author(s):  
N. A. Ahmad ◽  
A. A. Wheeler ◽  
W. J. Boettinger ◽  
G. B. McFadden
Keyword(s):  
Rapid Solidification ◽  
Phase Field ◽  
Field Model ◽  
Phase Field Model ◽  
Solute Drag ◽  
Solute Trapping

Dopant induced modifications in the physical properties of sprayed ZnO:In films

1993 ◽  
Vol 8 (5) ◽  
pp. 1052-1056 ◽  
Author(s):  
D.J. Goyal ◽  
Chitra Agashe ◽  
M.G. Takwale ◽  
V.G. Bhide ◽  
Shailaja Mahamuni ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Photoelectron Spectroscopy ◽  
Crystal Orientation ◽  
Spray Pyrolysis Technique ◽  
Small Addition ◽  
X Ray ◽  
Dopant Incorporation ◽  
Indium Doping ◽  
Dopant Level ◽  
Compositional Properties

Indium-doped zinc oxide (IZO) films were prepared by the spray pyrolysis technique. The effect of gradual incorporation of indium cations on the structural, electrical, and compositional properties of IZO films was studied in detail. It was observed that even a small addition of indium modifies the preferred growth of IZO film from the [002] direction to the [101] direction. Such a modification in growth pattern is a result of more nucleating centers created by indium doping. Indium dopant improves the electrical properties of the films. The carrier concentration depends mainly on the indium dopant level while the mobility is affected by the changes in crystal orientation that take place due to addition of dopants. X-ray photoelectron spectroscopy results show that indium doping does not lead to any stoichiometric changes in the IZO films and the dopant incorporation in the film is linearly proportional to that in the solution.

Crystal orientation dependence of impurity dopant incorporation in MOVPE-grown III–V materials

1992 ◽  
Vol 124 (1-4) ◽  
pp. 449-456 ◽  
Author(s):  
Makoto Kondo ◽  
Chikashi Anayama ◽  
Toshiyuki Tanahashi ◽  
Susumu Yamazaki
Keyword(s):  
Crystal Orientation ◽  
Orientation Dependence ◽  
Dopant Incorporation
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