Segregation and Crystallization Phenomena in Germanium

1982 ◽  
Vol 13 ◽  
Author(s):  
G. J. Clark ◽  
A. G. Cullis ◽  
D. C. Jacobson ◽  
J. M. Poate ◽  
Michael O. Thompson
Keyword(s):  
Liquid Phase ◽  
Cell Formation ◽  
Liquid Nitrogen Temperature ◽  
Orientation Dependence ◽  
Constitutional Supercooling ◽  
Segregation Coefficient ◽  
Interface Instability ◽  
Defect Production ◽  
Bi Segregation ◽  
Xecl Excimer Laser

ABSTRACTWhile many studies have been made of liquid phase epitaxy impurity trapping and segregation in Si little is known about the equivalent processes in Ge. In this paper we have laser annealed Ge <100> and <111> crystals implanted, at liquid nitrogen temperature, with 200 keV 210Bi ions to doses of 2 × 1015 and 1016 ions cm−2. The samples were annealed with Q-switched ruby lasers and an XeCl excimer laser. We have observed 1) velocity and orientation dependence of the Bi segregation coefficient 2) interface instability and cell formation resulting from constitutional supercooling and 3) amorphization and defect production at high velocities. The phenomena are shown to be analogous to those seen in Si.

scholarly journals A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2308 ◽  
Author(s):  
Kefeng Pan ◽  
Ying Li ◽  
Jiawei Zhang ◽  
Qing Zhao
Keyword(s):  
Liquid Phase ◽  
High Purity ◽  
Raw Materials ◽  
Low Cost ◽  
Crystallization Rate ◽  
Segregation Coefficient ◽  
Crystal Direction ◽  
Partial Recrystallization ◽  
Removal Ratio ◽  
Critical Raw Materials

As one of the critical raw materials, very pure gallium is important for the semiconductor and photoelectric industry. Unfortunately, refining gallium to obtain a purity that exceeds 99.99999% is very difficult. In this paper, a new, facile and efficient continuous partial recrystallization method to prepare gallium of high purity is investigated. Impurity concentrations, segregation coefficients, and the purification effect were measured. The results indicated that the contaminating elements accumulated in the liquid phase along the crystal direction. The order of the removal ratio was Cu > Mg > Pb > Cr > Zn > Fe. This corresponded to the order of the experimentally obtained segregation coefficients for each impurity: Cu < Mg < Pb < Cr < Zn < Fe. The segregation coefficient of the impurities depended strongly on the crystallization rate. All observed impurity concentrations were substantially reduced, and the purity of the gallium obtained after our refinement exceeded 99.99999%.

Liquid Phase Growth of Epitaxial Ni and Co Silicides by Pulsed Laser Irradiation

1983 ◽  
Vol 23 ◽  
Author(s):  
R. T. Tung ◽  
J. M. Gibson ◽  
D. C. Jacobson ◽  
J. M. Poate
Keyword(s):  
Liquid Phase ◽  
Single Crystal ◽  
Liquid Phase Epitaxy ◽  
Cell Formation ◽  
Pulsed Laser ◽  
Phase Growth ◽  
Interfacial Instabilities ◽  
Laser Melting ◽  
Liquid Phase Growth ◽  
Pulsed Laser Irradiation

ABSTRACTEpitaxial Ni and Co silicides have been fabricated using pulsed laser melting. Interfacial instabilities and cell formation are suppressed during the liquid-phase epitaxy by melting mono or disilicide layers. Single crystal NiSi2 and CoSi2 films have been grown on (100) and (111) Si following a post-anneal. This method does not require UHV deposition or reaction techniques.

A Study of Substrate Orientation Dependence of the Solid-Phase Epitaxial Growth of Amorphised GaAs

1998 ◽  
Vol 523 ◽  
Author(s):  
K. B. Belay ◽  
D. J. Llewellyn ◽  
M. C. Ridgway
Keyword(s):  
Epitaxial Growth ◽  
Rutherford Backscattering Spectrometry ◽  
Solid Phase ◽  
Liquid Nitrogen Temperature ◽  
Amorphous Layer ◽  
Orientation Dependence ◽  
Ex Situ ◽  
Cross Sectional ◽  
Substrate Orientation

AbstractIn-situ transmission electron microscopy (TEM) has been utilized in conjunction with conventional ex-situ Rutherford backscattering spectrometry and channeling (RBS/C), in-situ time resolved reflectivity (TRR) and ex-situ TEM to study the influence of substrate orientation on the solid-phase epitaxial growth (SPEG) of amorphised GaAs. A thin amorphous layer was produced on semi-insulating (100), (110) and (111) GaAs substrates by ion implantation of 190 and 200 keV Ga and As ions, respectively, to a total dose of 1e14/cm2. During implantation, substrates were maintained at liquid nitrogen temperature. In-situ annealing at ∼260°C was performed in the electron microscope and the data obtained was quantitatively analysed. It has been demonstrated that the non-planarity of the crystalline-amorphous (c/a)-interface was greatest for the (111) substrate orientation and least for the (110) substrate orientation. The roughness was measured in terms of the length of the a/c-interface in given window as a function of depth on a frame captured from the recorded video of the in-situ TEM experiments. The roughness of the c/a-interface was determined by the size of the angle subtended by the microtwins with respect to the interface on ex-situ TEM cross-sectional micrographs. The angle was both calculated and measured and was the largest in the case of (111) plane. The twinned fraction as a function of orientation, was calculated in terms of the disorder measured from the RBS/C and it was greatest for the (111) orientation.

Velocity and Orientation Dependence of Solute Trapping

1985 ◽  
Vol 57 ◽  
Author(s):  
M. J. Aziz ◽  
J. Y. Tsao ◽  
M. O. Thompson ◽  
P. S. Peercy ◽  
C. W. White
Keyword(s):  
Pulsed Laser ◽  
Orientation Dependence ◽  
Sufficient Accuracy ◽  
Segregation Coefficient ◽  
Solute Trapping ◽  
Impurity Atoms ◽  
Segregation Behavior ◽  
Functional Forms ◽  
Solid Liquid Interface ◽  
Solid Liquid

AbstractThe fraction of impurity atoms in the liquid at the solid-liquid interface that join the crystal, known as the segregation coefficient k, during rapid crystal growth is known to deviate away from the equilibrium value towards unity as the interface speed v increases. Several plausible models have been proposed that account qualitatively for this behavior with different functional forms of k(v). We report measurements of the segregation behavior during rapid solidification following pulsed laser melting of Bi-implanted Si. The velocity dependence and the orientation dependence of the segregation coefficient of Bi in Si has been determined to sufficient accuracy to allow us to distinguish between models. Implications for the mechanism of solute trapping are discussed.

Oscillatory Morphological Instabilities During Rapid Solidification A The Role of Diffusion In The Solid

1985 ◽  
Vol 51 ◽  
Author(s):  
Atul Bansal ◽  
Arijit Bose
Keyword(s):  
Diffusion Coefficient ◽  
Crystal Growth ◽  
Solid Phase ◽  
Constitutional Supercooling ◽  
System Stability ◽  
Segregation Coefficient ◽  
Critical Wavelength ◽  
Equilibrium Segregation ◽  
Diffusivity Ratio

ABSTRACTRecent results by Coriell and Sekerka [J. Crystal Growth, 61, 499(1983)] on the oscillatory instability of a planar rapidly solidifying binary melt are extended to include diffusion in the solid phase. Under assumptions equivalent to those made by Coriell and Sekerka, it is shown that no matter how small the diffusion coefficient is in the solid, the system is stable to all oscillatory and non-oscillatory disturbance modes if the modified constitutional supercooling criterion is satisfied and if the nonriequilibrium segregation coefficient is zero. Thus, a range of the non-equilibrium segregation parameter exists where these results allow the possibility of instability, whereas Coriell and Sekerka predict that the system will be stable.System stability is increased for both oscillatory and non-oscillatory modes. It is necessary for the diffusivity ratio Ds/D1 to be nearly 0.1 before oscillatory modes are affected. Both the critical wavelength of the disturbance as well as the oscillation frequency are reduced slightly from the case where diffusion in the solid is ignored.

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