A Set of Generalized Equations for Describing the Diffusion of Impurity Atoms and Point Defects

2019 ◽  
pp. 89-117
Keyword(s):  
Point Defects ◽  
Generalized Equations ◽  
Impurity Atoms

Atomic Scale Structure-Property Relationships of Defects and Interfaces in Ceramics

1998 ◽  
Vol 4 (S2) ◽  
pp. 556-557
Author(s):  
S. Stemmer ◽  
G. Duscher ◽  
E. M. James ◽  
M. Ceh ◽  
N.D. Browning
Keyword(s):  
Point Defects ◽  
High Resolution Electron Microscopy ◽  
Complete Characterization ◽  
Atomic Scale ◽  
Structure Property ◽  
Defect Engineering ◽  
Impurity Atoms ◽  
Structure Property Relationships ◽  
Resolution Electron ◽  
Scale Composition

The evaluation of the two dimensional projected atom column positions around a defect or an interface in an electronic ceramic, as it has been performed in numerous examples by (quantitative) conventional high-resolution electron microscopy (HRTEM), is often not sufficient to relate the electronic properties of the material to the structure of the defect. Information about point defects (vacancies, impurity atoms), and chemistry or bonding changes associated with the defect or interface is also required. Such complete characterization is a necessity for atomic scale interfacial or defect engineering to be attained.One instructive example where more than an image is required to understand the structure property relationships, is that of grain boundaries in Fe-doped SrTi03. Here, the different formation energies of point defects cause a charged barrier at the boundary, and a compensating space charge region around it. The sign and magnitude of the barrier depend very sensitively on the atomic scale composition and chemistry of the boundary plane.

Electrical Properties of Defects in Ga-Doped Ge Irradiated with Fast Electrons and Protons

2015 ◽  
Vol 242 ◽  
pp. 316-321
Author(s):  
Vadim V. Emtsev ◽  
Nikolay V. Abrosimov ◽  
Vitalii V. Kozlovski ◽  
Gagik A. Oganesyan
Keyword(s):  
Electrical Properties ◽  
Point Defects ◽  
Shallow Donor ◽  
Acceptor Impurity ◽  
Impurity States ◽  
Fast Electrons ◽  
Impurity Atoms ◽  
Order Of Magnitude ◽  
Donor Acceptor ◽  
P Type

Electrical properties of radiation-produced defects in p-Ge irradiated with MeV electrons and protons are investigated. The dominant defects in electron-irradiated p-Ge were found to be neutral for the most part, whereas they are electrically active in proton-irradiated materials. Evidently, the reactions between impurity atoms and intrinsic point defects leading to formation of secondary Ga-related defects in electron-and proton-irradiated p-Ge appear to be distinct. Production rates of radiation defects in n-Ge and p-Ge are compared. A marked difference in the removal rates of shallow donor/acceptor impurity states, at least by an order-of-magnitude, is thought to be due to greatly enhanced annihilation of Frenkel pairs in p-type Ge.

Point Defects and Diffusion in Semiconductors

MRS Bulletin ◽  
1991 ◽  
Vol 16 (11) ◽  
pp. 42-46 ◽  
Author(s):  
Ulrich M. Gösele ◽  
Teh Y. Tan
Keyword(s):  
Point Defects ◽  
Integrated Circuit ◽  
Diffusion Processes ◽  
Semiconductor Industry ◽  
Surface Oxidation ◽  
Optoelectronic Device ◽  
Intrinsic Point Defects ◽  
Impurity Atoms ◽  
Circuit Fabrication ◽  
Dopant Atoms

Semiconductor devices generally contain n- and p-doped regions. Doping is accomplished by incorporating certain impurity atoms that are substitutionally dissolved on lattice sites of the semiconductor crystal. In defect terminology, dopant atoms constitute extrinsic point defects. In this sense, the whole semiconductor industry is based on controlled introduction of specific point defects. This article addresses intrinsic point defects, ones that come from the native crystal. These defects govern the diffusion processes of dopants in semiconductors. Diffusion is the most basic process associated with the introduction of dopants into semiconductors. Since silicon and gallium arsenide are the most widely used semiconductors for microelectronic and optoelectronic device applications, this article will concentrate on these two materials and comment only briefly on other semiconductors.A main technological driving force for dealing with intrinsic point defects stems from the necessity to simulate dopant diffusion processes accurately. Intrinsic point defects also play a role in critical integrated circuit fabrication processes such as ion-implantation or surface oxidation. In these processes, as well as during crystal growth, intrinsic point defects may agglomerate and negatively impact the performance of electronic or photovoltaic devices. If properly controlled, point defects and their agglomerates may also be used to accomplish positive goals such as enhancing device performance or processing yield.

scholarly journals CALCULATION OF STATIC PARAMETERS OF SILICON DIODE CONTAINING δ-LAYER OF TRIPLE-CHARGED POINT DEFECTS IN SYMMETRIC p–n-JUNCTION

2018 ◽  
Vol 9 (2) ◽  
pp. 130-141
Author(s):  
N. A. Poklonski ◽  
A. I. Kovalev ◽  
N. I. Gorbachuk ◽  
S. V. Shpakovski
Keyword(s):  
Cross Section ◽  
Point Defects ◽  
Current Density ◽  
Reverse Bias ◽  
Nonlinear Differential Equations ◽  
Forward Bias ◽  
Practical Interest ◽  
Silicon Diode ◽  
Impurity Atoms ◽  
The Cross

The study of semiconductor materials and devices containing a narrow layer of impurity atoms and/or intrinsic point defects of the crystal lattice is of fundamental and practical interest. The aim of the study is to calculate the electric parameters of a symmetric silicon diode, in the flat p–n-junction of which a δ-layer of point triple-charged t-defects is formed. Such a diode is called p–t–n-diode, similarly to p–i–n-diode.Each t-defect can be in one of the three charge states (−1, 0, and +1; in the units of the elementary charge). It is assumed that at room temperature all hydrogen-like acceptors in p-region and hydrogen-like donors in n-region are ionized. It was assumed that the cross-section for v-band hole capture on t-defects is greater than the cross-section for c-band electron capture on t-defects.The system of stationary nonlinear differential equations, which describe in the drift-diffusion approximation a migration of electrons and holes in semiconductors, is solved numerically. The static capacityvoltage and current-voltage characteristics of the silicon diode with nondegenerate regions of pand n-type of electrical conductivity are calculated for forward and reverse electric bias voltage.It is shown by calculation that in the p–t–n-diode containing the δ-layer of t-defects, at the forward bias a region of current density stabilization occurs. At the reverse bias the current density in such a diode is much greater than the one in a p–n-diode without t-defects. With the reverse bias the capacitance of the p–t–n-diode, in contrast to the p–n-diode, increases at first and then decreases.

Simulation of Coupled Diffusion of Impurity Atoms and Point Defects under Nonequilibrium Conditions in Local Domain

2002 ◽  
Vol 178 (1) ◽  
pp. 196-209 ◽  
Author(s):  
O.I Velichko ◽  
V.A Dobrushkin ◽  
A.N Muchynski ◽  
V.A Tsurko ◽  
V.A Zhuk
Keyword(s):  
Point Defects ◽  
Local Domain ◽  
Impurity Atoms ◽  
Coupled Diffusion ◽  
Nonequilibrium Conditions

The Necessary Duration of a Molecular Dynamics Experiment for the Diffusion Coefficient Calculation

2018 ◽  
Vol 30 ◽  
pp. 22-27
Author(s):  
Gennady M. Poletaev ◽  
Ekaterina S. Medvedeva ◽  
Darya V. Novoselova ◽  
Irina V. Zorya ◽  
Mikhail D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficient ◽  
Melting Point ◽  
Hydrogen Atom ◽  
Point Defects ◽  
Interstitial Atom ◽  
Mean Square ◽  
Impurity Atoms ◽  
Metal Crystal

The evaluation of the necessary duration of a molecular dynamics experiment for the calculation of the diffusion coefficient at migration of different point defects in Ni (vacancy, bivacancy, self-interstitial atom, hydrogen atom) is held in the present work. It is shown that at the temperature higher than 0.6 of melting point is usually enough the simulation during of 100 ps for this. When calculating of the diffusion coefficient of impurity in the metal crystal, for example, of hydrogen, the decrease of error of mean-square displacements of impurity atoms can be achieved by introducing of a large number of the impurities.

Homo- and Hetero-Structure Formation in Semiconductors by Laser Radiation: First Stage of Quantum Cones Formation

2013 ◽  
Vol 205-206 ◽  
pp. 475-479 ◽  
Author(s):  
Artur Medvids ◽  
Pavels Onufrijevs ◽  
Edvins Dauksta ◽  
Nikolai A. Sobolev
Keyword(s):  
Laser Radiation ◽  
Solid Solutions ◽  
Point Defects ◽  
Radiation Absorption ◽  
Gradient Field ◽  
Hetero Structure ◽  
Impurity Atoms ◽  
Cone Formation ◽  
New Phase ◽  
Thermogradient Effect

A possibility of formingquantum cones (QC) by Nd:YAG laser radiation on the surface of semiconductorssuch as Si and Ge crystals, and SiGe and CdZnTe solid solutions has been shown.A two-stage mechanism of quantum cone formation has been proposed. The first stage is generation and redistribution of point defects (impurity atoms and intrinsic point defects – vacancies and self-interstitials) in a temperature gradient field, the so-called thermogradient effect. As a result a new phase is formed on the irradiated surface, for example a Ge phase forms on the surface of a SiGe solid solution. The second stage is characterized by mechanical plastic deformation of the strained top layer leading to the formation of quantum cones, due to selective laser radiation absorption of the top layer. The first stage is more difficult for understanding of the physical processes which takeplace during of growth of QC, especially in pure intrinsic elementary semiconductors (Ge, Si) and compounds (CdTe, GaAs). Therefore, this research is focused on the investigation of the first stage of QC formation by laser irradiation. As a result of the investigation, a new mechanism for p-n junction formation in the elementary semiconductors and heterojunction in solid solutions by laser radiation as a first stage of QC formation is proposed.

Non-equilibrium segregation in metals and alloys

1980 ◽  
Vol 295 (1413) ◽  
pp. 197-207 ◽  
Keyword(s):  
Point Defects ◽  
Driving Force ◽  
Corrosion Behaviour ◽  
Metals And Alloys ◽  
Impurity Atoms ◽  
Solute Atoms ◽  
Kinetics Of ◽  
Practical Implications ◽  
Equilibrium Segregation ◽  
Non Equilibrium

The phenomenon of non-equilibrium segregation of solute and impurity atoms at interfaces in quenched materials is defined and the driving force and kinetics of the segregation are shown to differ significantly from those of reversible equilibrium segregation. Large point defect supersaturations are produced during quenching, irradiation and sintering, and both enrichment and depletion of solute atoms at interfaces, associated with the flow of point defects to sinks, have been observed. Some of the quantitative and qualitative experimental data on non-equilibrium segregation are described and the current understanding of the mechanisms and kinetics are summarized. Finally, some of the practical implications of non-equilibrium segregation, in terms of the effects on the deformation, fracture and mechanical properties, corrosion behaviour and structural stabilities of quenched and irradiated metals and alloys, are outlined and possible methods of inhibiting segregation are suggested.

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