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Ichiro Yonenaga - One of the best experts on this subject based on the ideXlab platform.
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Dislocation impurity interaction in si
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2005Co-Authors: Ichiro YonenagaAbstract:Abstract Dynamic Dislocation–impurity interactions in CZ–Si doped with light impurity (N), acceptor (B), donor (P, As, Sb) and neutral (Ge) impurities were investigated in comparison with those in undoped CZ–Si. Dislocation generation was effectively suppressed in B-, P- and As-doped Si when the concentration was higher than 1019 cm−3, while Ge impurity did not strongly suppress Dislocation generation. Dislocations were immobilized by the stable complexes formed through the impurity segregation and reaction. It was found that B and N impurities promptly form strong locking agents, while P and As impurities form highly dense locking agents along Dislocations. Dislocation Velocity in Si doped with electrically active impurities increased with increasing concentrations of not only the donor (P, As, Sb) but also the acceptor (B) impurities in the temperature range of 650–950 °C. N and Ge impurities had no or little effect on the Velocity of Dislocations in motion. Co-doping of Si with Ge and B was effective for suppression of Dislocation generation and retardation of Dislocation Velocity at low temperatures.
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hardness yield strength and Dislocation Velocity in elemental and compound semiconductors
Materials Transactions, 2005Co-Authors: Ichiro YonenagaAbstract:Current knowledge on macroscopic plasticity indications, i.e., hardness and yield strength, and on microscopic indication, i.e., Velocity of individual Dislocations, in elemental and IV-IV, III-V, and II-VI compound semiconductors including GaN and ZnSe are reported and discussed on their mutual correlations. The Vickers hardness of the semiconductors can provide conventional information on the material plasticity in a wide temperature range up to their inciting points over a wide range of size scales in various material forms. Hardness H y in diamond- and sphalerite-type semiconductors has a universal relationship on their temperature dependence similar to the yield strength t y with a relation H v = (70-100) τ y in the low temperature region. Yield strength obtained by normal tensile or compression tests are expressed by an experimental equation as a function of the strain rate and temperature. The velocities of various types of Dislocations measured directly in several semiconductors are described with an empirical equation as a function of the stress and the temperature. Through the analysis of yield strength data in terms of the collective motif in in of Dislocations during the plastic deformation, the Dislocation motion. rate-controlling plastic deformation, are deduced. The activation energy for Dislocation motion has a linear relation to the band gap energy, depending on the types of semiconductors, elemental. III-V compounds, and II-VI compounds.
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Dislocation impurity interaction in si
Materials Science in Semiconductor Processing, 2003Co-Authors: Ichiro YonenagaAbstract:Abstract The dynamic interaction between Dislocations and impurities B, P and Ge in Si with concentrations up to 2.5×10 20 cm −3 is investigated by the etch-pit technique, in comparison with that of O impurity in Si. Dislocation generation from a surface scratch is strongly suppressed when the concentration of B and P impurities exceeds 1×10 19 cm −3 , originating from the immobilization by preferential impurity segregation. Dislocation Velocity in motion enhances on increasing the concentration in B and P impurities. Neutral impurity Ge has weak effect on Dislocation generation and Velocity enhancement.
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growth and Dislocation behavior in gesi bulk alloys
Physica B-condensed Matter, 1999Co-Authors: Ichiro YonenagaAbstract:Bulk crystals of Ge1−xSix alloys in the whole composition range 0
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Dislocation Velocity in gesi alloy
Applied Physics Letters, 1996Co-Authors: Ichiro Yonenaga, Koji SuminoAbstract:Velocities of Dislocations in single crystal Ge1−xSix alloy semiconductors with x=0.004–0.022 grown by the Czochralski method were investigated by means of etch pit technique in the temperature range 450–700 °C and the stress range 3–20 MPa. The Dislocation Velocity in the GeSi decreases monotonically with an increase in the Si content, reaching about a half of that in Ge at x=0.022. The dependencies of the Dislocation Velocity on stress and temperature in the alloys are expressed by the same type of empirical equation as those in other elemental and compound semiconductors.
Koji Sumino - One of the best experts on this subject based on the ideXlab platform.
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Dislocation Velocity in gesi alloy
Applied Physics Letters, 1996Co-Authors: Ichiro Yonenaga, Koji SuminoAbstract:Velocities of Dislocations in single crystal Ge1−xSix alloy semiconductors with x=0.004–0.022 grown by the Czochralski method were investigated by means of etch pit technique in the temperature range 450–700 °C and the stress range 3–20 MPa. The Dislocation Velocity in the GeSi decreases monotonically with an increase in the Si content, reaching about a half of that in Ge at x=0.022. The dependencies of the Dislocation Velocity on stress and temperature in the alloys are expressed by the same type of empirical equation as those in other elemental and compound semiconductors.
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Dislocation Velocity in indium phosphide
Applied Physics Letters, 1991Co-Authors: Ichiro Yonenaga, Koji SuminoAbstract:Velocities of α, β, and screw Dislocations in InP crystals generated from surface scratches were measured as a function of stress and temperature by means of the etch pit technique. Effects of Zn and S impurities, acting as acceptor and donor, respectively, on the Dislocation Velocity were also investigated. lt was found that Zn impurity strongly retards the motion of all types of Dislocations. On the other hand, S impurity is found to reduce the mobilities of β and screw Dislocations while it enhances the mobility of α Dislocations.
Vasily V. Bulatov - One of the best experts on this subject based on the ideXlab platform.
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stochastic simulation of Dislocation glide in tantalum and ta based alloys
Journal of The Mechanics and Physics of Solids, 2005Co-Authors: David J Srolovitz, Chaitanya Deo, Wei Cai, Vasily V. BulatovAbstract:We employ a kinetic Monte Carlo algorithm to simulate the motion of a1/2〈111〉-oriented screw Dislocation on a {011}-slip plane in body centered cubic Ta and Ta-based alloys. The Dislocation moves by the kink model: double kink nucleation, kink migration and kink–kink annihilation. Rates of these unit processes are parameterized based upon existing first principles data. Both short-range (solute–Dislocation core) and long-range (elastic misfit) interactions between the Dislocation and solute are considered in the simulations. Simulations are performed to determine Dislocation Velocity as a function of stress, temperature, solute concentration, solute misfit and solute–core interaction strength. The Dislocation Velocity is shown to be controlled by the rate of nucleation of double kinks and the dependence of the double kink nucleation rate on stress and temperature are consistent with existing analytical predictions. In alloys, Dislocation Velocity depends on both the short- and long-range solute Dislocation interactions as well as on the solute concentration. The short-range solute–core interactions are shown to dominate the effects of alloying on Dislocation mobility. The present simulation method provides the critical link between atomistic calculations of fundamental Dislocation and solute properties and large scale Dislocation dynamics that typically employ empirical equations of motion.
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kinetic monte carlo modeling of Dislocation motion in bcc metals
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001Co-Authors: Vasily V. Bulatov, Ali S. ArgonAbstract:Abstract We present a kinetic Monte Carlo (kMC) simulation method for modeling screw Dislocation motion in BCC metals on the micron–second scales, using inputs from atomistic simulations of core mechanisms on the angstrom–picosecond scale. The simulations use atomistic input such as double-kink nucleation energy and kink mobility, include linear elastic (Peach–Koehler) interactions between Dislocation segments, and predict overall Dislocation Velocity at different temperature and stress states. In addition, an important mechanism, namely, the spontaneous superjog growth and debris loop nucleation, is identified in the kMC simulation as an important factor controlling the Dislocation motion in the high stress and medium temperature regime.
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Dislocation motion in bcc metals by molecular dynamics
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001Co-Authors: Jinpeng Chang, Vasily V. BulatovAbstract:Abstract We performed molecular dynamics (MD) simulation of edge Dislocations in BCC metal Mo with 1/2〈1 1 1〉 Burgers vector gliding on (1 1 0) plane using the Finnis–Sinclair N-body empirical potential and periodic boundary conditions (PBC). The profile of Dislocation line, extracted from atomic displacements during MD simulation, suggests a dominant mechanism of double-kink nucleation, without appreciable kink migration. This observation is consistent with further simulations in which Dislocations with pre-existing kinks are observed to move at the same Velocity as the initially straight Dislocations. Our results show a linear stress dependence of the Dislocation Velocity and a decrease of mobility with increasing temperature, both features interpreted as signifying that the simulations pertain to the viscous phonon drag regime of Dislocation mobility.
Xiaowei Wang - One of the best experts on this subject based on the ideXlab platform.
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Dislocation Velocity exponent and the strain rate
Journal of Materials Science & Technology, 2009Co-Authors: Hongyan Liu, Xiaowei WangAbstract:The process of Dislocation multiplication has been described hv chaos theory, trying to reveal the connection between the microstructures on the mesoscopic scale and the mechanical properties of material on the macroscopic scale. The relationship between the Dislocation Velocity exponent and the maximum of strain rate is given. The results obtained from logistic equation with exponent and the Dislocation multiplication dynamic equation are compared. A scale law in one-dimension-map model with exponent is shown when the exponents of equations are changed.
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Dislocation Velocity exponent and Dislocation multiplication dynamic bifurcation
Physics Letters A, 1995Co-Authors: Xiaowei Wang, C W LungAbstract:In this paper, we present a new viewpoint of the Dislocation Velocity exponent based on the iteration model of Dislocation multiplication. The results indicate that there is a relation between the Dislocation Velocity exponent and the Dislocation multiplication dynamic bifurcation with a nonlinear character in the plastic deformation of materials.
J F Gibbons - One of the best experts on this subject based on the ideXlab platform.
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dependence of misfit Dislocation velocities upon growth technique and oxygen content in strained gexsi1 x si 100 heterostructures
Applied Physics Letters, 1991Co-Authors: R Hull, J C Bean, D B Noble, J L Hoyt, J F GibbonsAbstract:Misfit Dislocation velocities in strained GexSi1−x/Si(100) heterostructures are compared for layers grown by molecular beam epitaxy and limited reaction processing. We demonstrate that velocities are substantially lower in structures with oxygen concentrations ∼1020 cm−3 compared to layers with oxygen concentrations ∼1018 cm−3. For layers with the lower oxygen concentration, the sample growth technique does not appear to be a significant factor affecting misfit Dislocation Velocity.