Segregation During Magnetically-Stabilized Liquid-Encapsulated Growth of Compound Semiconductor Crystals

2000 ◽  
Author(s):  
Nancy Ma ◽  
David F. Bliss ◽  
George G. Bryant
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Applied Magnetic Field ◽  
Dopant Concentration ◽  
Axial Magnetic Field ◽  
Compound Semiconductor ◽  
Semiconductor Crystal ◽  
Semiconductor Crystals ◽  
Single Compound ◽  
Relative Motions

Abstract During the magnetically-stabilized liquid-encapsulated Czochralski (MLEC) process, a single compound semiconductor crystal is grown by the solidification of an initially molten semiconductor (melt) contained in a crucible. The melt is doped with an element in order to vary the electrical and/or optical properties of the crystal. During growth, the so-called melt-depletion flow caused by the opposing relative motions of the encapsulant-melt interface and the crystal-melt interface can be controlled with an externally applied magnetic field. The convective dopant transport during growth driven by this melt motion produces non-uniformities of the dopant concentration in both the melt and the crystal. This paper presents a model for the unsteady transport of a dopant during the MLEC process with an axial magnetic field. Dopant distributions in the crystal and in the melt at several different stages during growth are presented.

Diffusion-Controlled Dopant Transport During Magnetically-Stabilized Liquid-Encapsulated Czochralski Growth of Compound Semiconductor Crystals

2001 ◽  
Vol 123 (4) ◽  
pp. 893-898 ◽  
Author(s):  
Joseph L. Morton ◽  
Nancy Ma ◽  
David F. Bliss ◽  
George G. Bryant
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Dopant Concentration ◽  
Axial Magnetic Field ◽  
Compound Semiconductor ◽  
Czochralski Growth ◽  
Semiconductor Crystal ◽  
Semiconductor Crystals ◽  
Diffusion Controlled ◽  
Single Compound

During the magnetically-stabilized liquid-encapsulated Czochralski (MLEC) process, a single compound semiconductor crystal is grown by the solidification of an initially molten semiconductor (melt) contained in a crucible. The melt is doped with an element in order to vary the electrical and/or optical properties of the crystal. During growth, the so-called melt-depletion flow caused by the opposing relative velocities of the encapsulant-melt interface and the crystal-melt interface can be controlled with an externally applied magnetic field. The convective dopant transport during growth driven by this melt motion produces nonuniformities of the dopant concentration in both the melt and the crystal. This paper presents a model for the unsteady transport of a dopant during the MLEC process with an axial magnetic field. Dopant distributions in the crystal and in the melt at several different stages during growth are presented.

Semiconductor Crystal Growth by the Vertical Bridgman Process With Transverse Rotating Magnetic Fields

2006 ◽  
Vol 129 (2) ◽  
pp. 241-243 ◽  
Author(s):  
X. Wang ◽  
N. Ma
Keyword(s):  
Magnetic Field ◽  
Crystal Growth ◽  
Magnetic Fields ◽  
Applied Magnetic Field ◽  
Rotating Magnetic Field ◽  
Semiconductor Crystal ◽  
Rotating Magnetic Fields ◽  
Electrically Conducting ◽  
Vertical Bridgman ◽  
Bridgman Process

During the vertical Bridgman process, a single semiconductor crystal is grown by the solidification of an initially molten semiconductor contained in an ampoule. The motion of the electrically conducting molten semiconductor can be controlled with an externally applied magnetic field. This paper treats the flow of a molten semiconductor and the dopant transport during the vertical Bridgman process with a periodic transverse or rotating magnetic field. The frequency of the externally applied magnetic field is sufficiently low that this field penetrates throughout the molten semiconductor. Dopant distributions in the crystal are presented.

scholarly journals Magnetically Induced Carrier Distribution in a Composite Rod of Piezoelectric Semiconductors and Piezomagnetics

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3115 ◽  
Author(s):  
Guolin Wang ◽  
Jinxi Liu ◽  
Wenjie Feng ◽  
Jiashi Yang
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Axial Magnetic Field ◽  
Semiconductor Layer ◽  
Carrier Distribution ◽  
Composite Rod ◽  
Piezoelectric Effects ◽  
Potential Applications ◽  
Piezoelectric Coupling ◽  
Piezoelectric Semiconductors

In this work, we study the behavior of a composite rod consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under an applied axial magnetic field. Based on the phenomenological theories of piezoelectric semiconductors and piezomagnetics, a one-dimensional model is developed from which an analytical solution is obtained. The explicit expressions of the coupled fields and the numerical results show that an axially applied magnetic field produces extensional deformation through piezomagnetic coupling, the extension then produces polarization through piezoelectric coupling, and the polarization then causes the redistribution of mobile charges. Thus, the composite rod exhibits a coupling between the applied magnetic field and carrier distribution through combined piezomagnetic and piezoelectric effects. The results have potential applications in piezotronics when magnetic fields are relevant.

Thermoelectrically Driven Melt Motion During Floating Zone Crystal Growth With an Axial Magnetic Field

1998 ◽  
Vol 120 (4) ◽  
pp. 839-843 ◽  
Author(s):  
Y. Y. Khine ◽  
J. S. Walker
Keyword(s):  
Magnetic Field ◽  
Crystal Growth ◽  
Axial Magnetic Field ◽  
Azimuthal Velocity ◽  
Liquid Interfaces ◽  
Floating Zone ◽  
Semiconductor Crystal ◽  
Electrical Conductivities ◽  
Solid Liquid ◽  
Key Parameter

During semiconductor crystal growth with an externally applied magnetic field, thermoelectric currents may drive a melt circulation which affects the properties of the crystal. This paper treats a model problem for a floating zone process with a uniform axial magnetic field, with planar solid-liquid interfaces, with a cylindrical free surface, with a parabolic temperature variation along the crystal-melt interface, and with an isothermal feed rod-melt interface. The ratio of the electrical conductivities of the liquid and solid is a key parameter. The azimuthal velocity is much larger than the radial or axial velocity. There is radially outward flow near the crystal-melt interface which should be beneficial for the mass transport of dopants and species.

scholarly journals Transverse electromagnetic Hermite–Gaussian mode-driven direct laser acceleration of electron under the influence of axial magnetic field

2018 ◽  
Vol 36 (1) ◽  
pp. 154-161 ◽  
Author(s):  
Harjit Singh Ghotra ◽  
Dino Jaroszynski ◽  
Bernhard Ersfeld ◽  
Nareshpal Singh Saini ◽  
Samuel Yoffe ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Laser Beam ◽  
Applied Magnetic Field ◽  
Axial Magnetic Field ◽  
Energy Gain ◽  
Electron Interaction ◽  
Direct Laser ◽  
Tem Mode ◽  
Laser Acceleration ◽  
Transverse Electromagnetic

AbstractHermite–Gaussian (HG) laser beam with transverse electromagnetic (TEM) mode indices (m, n) of distinct values (0, 1), (0, 2), (0, 3), and (0, 4) has been analyzed theoretically for direct laser acceleration (DLA) of electron under the influence of an externally applied axial magnetic field. The propagation characteristics of a TEM HG beam in vacuum control the dynamics of electron during laser–electron interaction. The applied magnetic field strengthens the $\vec v \times \vec B$ force component of the fields acting on electron for the occurrence of strong betatron resonance. An axially confined enhanced acceleration is observed due to axial magnetic field. The electron energy gain is sensitive not only to mode indices of TEM HG laser beam but also to applied magnetic field. Higher energy gain in GeV range is seen with higher mode indices in the presence of applied magnetic field. The obtained results with distinct TEM modes would be helpful in the development of better table top accelerators of diverse needs.

scholarly journals Subnanosecond breakdown of air-insulated coaxial line initiated by runaway electrons in the presence of a strong axial magnetic field

2021 ◽  
Vol 2064 (1) ◽  
pp. 012003
Author(s):  
G A Mesyats ◽  
E A Osipenko ◽  
K A Sharypov ◽  
V G Shpak ◽  
S A Shunailov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Voltage Pulse ◽  
Plasma Layer ◽  
Axial Magnetic Field ◽  
Coaxial Line ◽  
Runaway Electrons ◽  
Cathode Plasma ◽  
Fast Electrons

Abstract Flow of runaway electrons (RAEs) propagating in a radial, air-filled gap of coaxial line (CL) changes the dynamics of breakdown in the field of traveling voltage pulse. However, despite the effect of RAEs, breakdown does not occur if subnanosecond pulse is less in duration and amplitude than some values. In this work, we study the influence of an external axial magnetic field (B z) on the breakdown development. We demonstrate the transformation of the voltage pulse reflection from the ionized (breakdown) zone with changing B z. Due to gyration of fast electrons in an applied magnetic field, the gas region ionized by RAEs does not reach the anode. The ionized bridge between the cathode and anode is gradually replaced by a near-cathode plasma layer representing a discrete, reflecting/absorbing inhomogeneity in the CL.

scholarly journals Growth of Binary Alloyed Semiconductor Crystals by the Vertical Bridgman-Stockbarger Process with a Strong Magnetic Field

2005 ◽  
Vol 127 (3) ◽  
pp. 523-528 ◽  
Author(s):  
Stephen J. LaPointe ◽  
Nancy Ma ◽  
D. W. Mueller
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Convective Transport ◽  
Transient Model ◽  
Buoyant Convection ◽  
Semiconductor Crystals ◽  
Thermally Driven ◽  
Vertical Bridgman ◽  
Compositional Variations ◽  
Alloyed Semiconductor

This paper presents a model for the unsteady species transport for the growth of alloyed semiconductor crystals during the vertical Bridgman-Stockbarger process with a steady axial magnetic field. During growth of alloyed semiconductors such as germanium-silicon (GeSi) and mercury-cadmium-telluride (HgCdTe), the solute’s concentration is not small, so that density differences in the melt are very large. These compositional variations drive compositionally driven buoyant convection, or solutal convection, in addition to thermally driven buoyant convection. These buoyant convections drive convective transport, which produces nonuniformities in the concentration in both the melt and the crystal. This transient model predicts the distribution of species in the entire crystal grown in a steady axial magnetic field. The present study presents results of concentration in the crystal and in the melt at several different stages during crystal growth.

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