Separation of the Driving Force and Radiation-Enhanced Dislocation Glide in 4H-SiC

2012 ◽  
Vol 725 ◽  
pp. 35-40 ◽  
Author(s):  
Koji Maeda ◽  
Rii Hirano ◽  
Yuki Sato ◽  
Michio Tajima
Keyword(s):  
Driving Force ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Dislocation Velocity ◽  
Electronic Excitations ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Simultaneous Measurements ◽  
Pl Mapping ◽  
Anomalous Expansion

Anomalous expansion of stacking faults (SFs) induced in 4H-SiC under electronic excitations is driven by an electronic force and is achieved by enhanced glide of partial dislocations. An experimental attempt to separate the two physically different effects has been made by conducting photoluminescence (PL) mapping experiments which allowed simultaneous measurements of partial dislocation velocity and SF-originated PL intensity the latter of which is proposed to be related to the driving force for SF expansion through the density of free excitons planarly confined in the SF.

Photoluminescence Study of the Driving Force for Stacking Fault Expansion in 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 395-398 ◽  
Author(s):  
Rii Hirano ◽  
Yuki Sato ◽  
Michio Tajima ◽  
Kohei M. Itoh ◽  
Koji Maeda
Keyword(s):  
Driving Force ◽  
Stacking Faults ◽  
Excitation Intensity ◽  
Band Edge Emission ◽  
Edge Emission ◽  
Sign Reversal ◽  
Laser Illumination ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Lattice Heating

We investigated expansion velocities of Shockley stacking faults (SSFs) in 4H-silicon carbide under laser illumination using photoluminescence methods. The experiments showed that the velocity of SSF expansion or the glide velocity of SSF-bounding 30°-Si(g) partial dislocations (PD) is supralinearly dependent on the excitation intensity. We estimated sample temperature by analyzing the broadening of band-edge emission and concluded that the lattice heating by laser illumination is not the cause of the enhanced dislocation glide. The supralinear dependence can be accounted for by a photo-induced sign reversal of the effective formation energy of SSF acting as the driving force of SSF expansion under the illumination.

Interaction between Recombination Enhanced Dislocation Glide Process Activated Basal Stacking Faults and Threading Dislocations in 4H-Silicon Carbide Epitaxial Layers

2007 ◽  
Vol 994 ◽  
Author(s):  
Yi Chen ◽  
Michael Dudley ◽  
Kendrick X Liu ◽  
Robert E Stahlbush
Keyword(s):  
Silicon Carbide ◽  
Partial Dislocation ◽  
Displacement Vector ◽  
Stacking Faults ◽  
Epitaxial Layers ◽  
Threading Dislocations ◽  
Screw Dislocations ◽  
Dislocation Glide ◽  
Shockley Partial ◽  
Partial Dislocations

AbstractElectron-hole recombination enhanced glide of Shockley partial dislocations bounding expanding stacking faults and their interactions with threading dislocations in 4H silicon carbide epitaxial layers have been studied using synchrotron white beam X-ray topography and in situ electroluminescence. The mobile silicon-core Shockley partial dislocations bounding the stacking faults are able to cut through threading edge dislocations leaving no trailing dislocation segments in their wake. However, when the Shockley partial dislocations interact with threading screw dislocations, trailing 30o partial dislocation dipoles are initially deposited in their wake due to the pinning effect of the threading screw dislocations. These dipoles spontaneously snap into their screw orientation, regardless the normally immobile carbon-core Shockley partial dislocation components in the dipoles. They subsequently cross slip and annihilate, leaving a prismatic stacking fault in (2-1-10) plane with the displacement vector 1/3[01-10].

Controlling Planar Defects in 3C-SiC: Ways to Wake it up as a Practical Semiconductor

2015 ◽  
Vol 821-823 ◽  
pp. 108-114 ◽  
Author(s):  
Hiroyoki Nagasawa ◽  
Ramya Gurunathan ◽  
Maki Suemitsu
Keyword(s):  
Phase Boundary ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Planar Defects ◽  
Forest Dislocation ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Blocking Property ◽  
Trapezoidal Plate ◽  
Anti Phase Boundary

Eelectrically active defects in 3C–SiC are investigated by considering the structures and interactions of planar defects. An anti-phase boundary (APB) largely degrades the blocking property of semiconductor devices due to its semimetallic nature. Although APBs can be eliminated by orienting the specific polar face of 3C-SiC along a particular direction, stacking faults (SFs) cannot be eliminated due to Shockley-type partial dislocation glide. SFs with Shockley-type partial dislocations form a trapezoidal plate which expands the Si-terminated surface with increasing 3C-SiC thickness. Although the density of SFs can be reduced by counter termination, specific cross-junctions between a pair of counter SFs forms a forest dislocation, and this is regarded as an electrically active defect. This paper proposes an effective way to suppress the forest dislocations and APBs which nucleate during 3C-SiC growth.

Structure of stacking faults in pyrite using TEM techniques

1992 ◽  
Vol 50 (1) ◽  
pp. 358-359
Author(s):  
Raja Subramanian ◽  
Kenneth S. Vecchio
Keyword(s):  
Lattice Structure ◽  
Stacking Faults ◽  
Covalent Bond ◽  
Group Symmetry ◽  
Iron Pyrite ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Transmission Electron ◽  
Contrast Analysis ◽  
Chlorine Ions

The structure of stacking faults and partial dislocations in iron pyrite (FeS2) have been studied using transmission electron microscopy. Pyrite has the NaCl structure in which the sodium ions are replaced by iron and chlorine ions by covalently-bonded pairs of sulfur ions. These sulfur pairs are oriented along the <111> direction. This covalent bond between sulfur atoms is the strongest bond in pyrite with Pa3 space group symmetry. These sulfur pairs are believed to move as a whole during dislocation glide. The lattice structure across these stacking faults is of interest as the presence of these stacking faults has been preliminarily linked to a higher sulfur reactivity in pyrite. Conventional TEM contrast analysis and high resolution lattice imaging of the faulted area in the TEM specimen has been carried out.

Stacking Faults and 3C Quantum Wells in Hexagonal SiC Polytypes

2006 ◽  
Vol 527-529 ◽  
pp. 351-354 ◽  
Author(s):  
M.S. Miao ◽  
Walter R.L. Lambrecht
Keyword(s):  
Band Structure ◽  
Quantum Wells ◽  
First Principles ◽  
Driving Force ◽  
Stacking Faults ◽  
Band Gaps ◽  
Partial Dislocations ◽  
Band Structure Calculations ◽  
Thermodynamic Driving Force ◽  
Structure Calculations

The electronic driving force for growth of stacking faults (SF) in n-type 4H SiC under annealing and in operating devices is discussed. This involves two separate aspects: an overall thermodynamic driving force due to the capture of electrons in interface states and the barriers that need to be overcome to create dislocation kinks which advance the motion of partial dislocations and hence expansion of SF. The second problem studied in this paper is whether 3C SiC quantum wells in 4H SiC can have band gaps lower than 3C SiC. First-principles band structure calculations show that this is not the case due to the intrinsic screening of the spontaneous polarization fields.

Tailoring Microstructures Under Strong Non-Equilibrium Conditions: A Feasible Path Towards High JC in Melt Textured YBa2Cu3O7

2000 ◽  
Vol 659 ◽  
Author(s):  
Felip Sandiumenge ◽  
Jérôme Plain ◽  
Teresa Puig ◽  
Xavier Obradors ◽  
Jacques Rabier ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Partial Dislocation ◽  
Enhancement Factor ◽  
Stacking Faults ◽  
Equilibrium Conditions ◽  
Pinning Centers ◽  
Partial Dislocations ◽  
High Oxygen Pressure ◽  
Density Analysis ◽  
Feasible Path

ABSTRACTMelt textured YBa2Cu3O/Y2BaCuO5 were post processed by high oxygen pressure for different periods and temperatures. This process permits the control of the microstructure, in particular the growth and shape of the stacking faults and thereby the partial dislocation density. Analysis of the Jc(H,T) behavior allow to separate the contribution of Y2BaCuO5 interface from that of dislocations. It is shown that the in-plane partial dislocations act as point-like pinning centers increasing Jc up to 180% but this enhancement factor is counterbalanced by the effect of the stacking faults associated to the partial dislocations.

Molecular Dynamics studies of Dislocations in SI

1989 ◽  
Vol 163 ◽  
Author(s):  
M.S. Duesbery ◽  
D.J. Michel ◽  
B. Joos
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Partial Dislocation ◽  
Silicon Lattice ◽  
Dislocation Glide ◽  
Partial Dislocations ◽  
Shear Strains ◽  
Free Environment

AbstractThe mobility of dislocations in a model Silicon lattice is examined at an atomistic level using molecular dynamics. Straight and double-kinked 30° and 90° partial dislocation glide-set dipoles are modelled in a strain-free environment: reconstruction and antiphase defects are found to be present for 30° partial dislocations. The effects of applied shear strains and of temperatures up to the melting point are considered.

Densification Behavior in Spark-Plasma-Sintering of MgAl2O4 Spinel

2010 ◽  
Vol 654-656 ◽  
pp. 1986-1989
Author(s):  
Koji Morita ◽  
Byung Nam Kim ◽  
Hidehiro Yoshida ◽  
Keijiro Hiraga
Keyword(s):  
Effective Stress ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Dislocation Motion ◽  
Densification Rate ◽  
Densification Mechanism ◽  
Partial Dislocations ◽  
Plasma Sintering ◽  
Rate Relationship ◽  
Spark Plasma

The densification mechanism in park-plasma-sintering (SPS) processing was examined in MgAl2O4 spinel. As the relative density ρt increases, that is, as the effective stress σeff decreases, stress exponent n evaluated from effective stress-densification rate relationship continuously varies from n  4 to n  1. TEM observation shows that significant stacking faults caused by partial dislocations are frequently observed in the low ρt region. The results suggest that, for spinel, the predominant densification mechanism in SPS processing changes with ρt from plastic flow by a partial dislocation motion in the low ρt region (n  4) to diffusion-related creep in the high ρt region (n  1).

Stacking faults and dislocations in titanium dioxide, with special reference to non-stoichiometry

1963 ◽  
Vol 276 (1367) ◽  
pp. 542-552 ◽  
Keyword(s):  
Titanium Dioxide ◽  
Partial Dislocation ◽  
Stoichiometric Composition ◽  
Stacking Faults ◽  
Dislocation Loops ◽  
Microscopical Investigation ◽  
Burgers Vector ◽  
Vacancy Clusters ◽  
Partial Dislocations ◽  
Electron Microscopical

A detailed electron microscopical investigation has been made of the stacking faults and dislocations observed in thin films of titanium dioxide grown on the (100) faces of titanium carbide crystals. The large stacking faults formed during the growth process lie on a {101} plane, but they often change from one plane to another of the same family, sometimes on too fine a scale to be clearly resolved. The fault is terminated by a partial dislocation having a vector of the 1/2<101>-type; if the specimen is heated in the microscope, when it becomes non-stoichiometric, the fault anneals out by one of two mechanisms. The first mechanism involves the glide of the partial dislocation terminating the fault, and the second the growth of small dislocation loops formed by the condensation of vacancies introduced as a result of deviations from the stoichiometric composition. Contrast experiments show that the observed dislocations are of two types. The first are dissociated dislocations having a partial 1/2<101> vector, glissile on {101} planes and associated with a stacking fault. The second type of dislocation are undissociated and have a <001> Burgers vector. A sessile configuration is also formed by an interaction between dislocations with 1/2<101> and <001> and Burgers vector. An interaction between glissile partial dislocations and vacancy clusters also occurs, and it is suggested that this is a possible mechanism for the increased yield stress produced when TiO 2 becomes substoichiometric.

The study of defects in Sb2S3 by method of direct lattice resolution

1978 ◽  
Vol 36 (1) ◽  
pp. 312-313
Author(s):  
V.M. Kosevich ◽  
A.A. Sokol ◽  
A.G. Bagmut
Keyword(s):  
Defect Structure ◽  
Partial Dislocation ◽  
Stacking Faults ◽  
Substrate Plane ◽  
Partial Dislocations ◽  
Displacement Vectors ◽  
Initial Stage ◽  
Direct Lattice ◽  
Lattice Resolution ◽  
Deposited Films

1.Sb2S3 has the orthorombic lattice with a=11,23;b=11,31; c=3,84 Å. Its crystal structure is constructed of the double ribbons of antimony and sulphur atoms,parallel to [00l].Vacuum deposited films of Sb2S3 re amorphous{they were crystallyzed in spherolite mode by the electronbeam heating.The study of defect structure of the Sb2S3 spherolite crystals by method of direct lattice resolution was the aim of present work.The images of (100),(200),(010),(020),(110) and (110) planes were obtained.2.Several types of the ribbons stacking faults were obserwed in Sb2S3 crystals with (001) parallel to the substrate plane (Fig.1).The stac-kingfault planes and their displacement vectors R are the following: a) (010),(110),R=1/2 [010];b) (100),R=1/2 [210],R=1/4[210].3.There were obtained the images of partial dislocations with b=1/2 [010] and small-andle boundaries,consisted of the dissociated partial dislocation pairs,in Sb2s3 crystals with (100) and (010) planes parallel to the substrate.Small-angle boundaries appeared on initial stage of the spherolite growth,when splitting of spherolite single-crystal nucleus was taking place (Fig.2).

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