Mechanisms of Stacking Fault Growth in SiC PiN Diodes

2004 ◽  
Vol 815 ◽  
Author(s):  
R. E. Stahlbush ◽  
M. E. Twigg ◽  
J. J. Sumakeris ◽  
K. G. Irvine ◽  
P. A. Losee
Keyword(s):  
Basal Plane ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Drift Region ◽  
Pin Diodes ◽  
Current Time ◽  
Partial Dislocations ◽  
Initial Evolution ◽  
A Chain ◽  
Fault Growth

AbstractThe early development of stacking faults in SiC PiN diodes fabricated on 8° off c-axis 4H wafers has been studied. The 150μm drift region and p-n junction were epitaxially grown. The initial evolution of the stacking faults was examined by low injection electroluminescence using current-time product steps as low as 0.05 coul/cm2. The properties of the dislocations present before electrical stressing were determined based on previously observed differences of Si-core and C-core partial dislocations and the patterns of stacking fault expansion. The initial stacking fault expansion often forms a chain of equilateral triangles and at higher currents and/or longer times these triangles coalesce. All of the faulting examined in this paper originated between 10 and 40 μm below the SiC surface. The expansion rate of the bounding partial dislocations is very sensitive to the partials' line directions, their core types and the density of kinks. From these patterns it is concluded that the stacking faults originate from edge-like basal plane dislocations that have Burgers vectors either parallel or anti-parallel to the off-cut direction. Evidence for dislocation conversions between basal-plane and threading throughout the epitaxial drift region is also presented.

Effect of Stacking Faults Originating from Half Loop Arrays on Electrical Behavior of 10 kV 4H-SiC PiN Diodes

2012 ◽  
Vol 717-720 ◽  
pp. 387-390 ◽  
Author(s):  
Robert E. Stahlbush ◽  
Qing Chun Jon Zhang ◽  
Anant K. Agarwal ◽  
Nadeemullah A. Mahadik
Keyword(s):  
Basal Plane ◽  
Forward Bias ◽  
Stacking Faults ◽  
Device Fabrication ◽  
Electrical Behavior ◽  
Forward Voltage ◽  
Pin Diodes ◽  
Electrical Stress ◽  
Half Loop

The effects of Shockley stacking faults (SSFs) that originate from half loop arrays (HLAs) on the forward voltage and reverse leakage were measured in 10 kV 4H-SiC PiN diodes. The presence of HLAs and basal plane dislocations in each diode in a wafer was determined by ultraviolet photoluminescence imaging of the wafer before device fabrication. The SSFs were expanded by electrical stressing under forward bias of 30 A/cm2, and contracted by annealing at 550 °C. The electrical stress increased both the forward voltage and reverse leakage. Annealing returned the forward voltage and reverse leakage to nearly their original behavior. The details of SSF expansion and contraction from a HLA and the effects on the electrical behavior of the PiN diodes are discussed.

Dislocations and stacking faults in stainless steel

1957 ◽  
Vol 240 (1223) ◽  
pp. 524-538 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Grain Boundaries ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Thin Sections ◽  
Partial Dislocations ◽  
Transmission Electron

Further experiments by transmission electron microscopy on thin sections of stainless steel deformed by small amounts have enabled extended dislocations to be observed directly. The arrangement and motion of whole and partial dislocations have been followed in detail. Many of the dislocations are found to have piled up against grain boundaries. Other observations include the formation of wide stacking faults, the interaction of dislocations with twin boundaries, and the formation of dislocations at thin edges of the foils. An estimate is made of the stacking-fault energy from a consideration of the stresses present, and the properties of the dislocations are found to be in agreement with those expected from a metal of low stacking-fault energy.

scholarly journals Dissociation Behavior of Dislocations in Ice

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 386
Author(s):  
Takeo Hondoh
Keyword(s):  
Basal Plane ◽  
Dislocation Line ◽  
Stacking Faults ◽  
Physical Models ◽  
Time Constants ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Perfect Dislocation ◽  
Low Energies ◽  
Dissociated State

Dislocations in ice behave very differently from those in other materials due to the very low energies of stacking faults in the ice basal plane. As a result, the dislocations dissociate on the basal plane, from a perfect dislocation into two partial dislocations with equilibrium width we ranging from 20 to 500 nm, but what is the timescale to reach this dissociated state? Using physical models, we estimate this timescale by calculating two time-constants: the dissociation-completing time td and the dissociation-beginning time tb. These time constants are calculated for two Burgers vectors as a function of temperature. For perfect dislocations with Burgers vector <c + a>, td is more than one month even at the melting temperature TM, and it exceeds 103 years below −50 ℃, meaning that the dissociation cannot be completed during deformation over laboratory timescales. However, in this case the beginning time tb is less than one second at TM, and it is within several tens of minutes above −50 ℃. These dislocations can glide on non-basal planes until they turn to the dissociated state during deformation, finally resulting in sessile extended dislocations of various widths approaching to the equilibrium value we. In contrast, for perfect dislocations with Burgers vector <a>, td is less than one second above −50 ℃, resulting in glissile extended dislocations with the equilibrium width we on the basal plane. This width is sensitive to the shear stress τ exerted normal to the dislocation line, leading to extension of the intervening stacking fault across the entire crystal grain under commonly accessible stresses. Also, due to the widely dissociated state, dislocations <a> cannot cross-slip to non-basal planes. Such behavior of extended dislocations in ice are notable when compared to those of other materials.

Threading Dislocation Density Reduction in GaN/Sapphire Heterostructures.

1999 ◽  
Vol 595 ◽  
Author(s):  
A. Kvit ◽  
A. K. Sharma ◽  
J. Narayan
Keyword(s):  
Basal Plane ◽  
Stacking Faults ◽  
High Density ◽  
Thin Layers ◽  
Interfacial Region ◽  
Threading Dislocation ◽  
Threading Dislocations ◽  
Misfit Dislocations ◽  
Plan View ◽  
Partial Dislocations

AbstractLarge lattice mismatch between GaN and α-Al2O3 (15%) leads to the possibility of high threading dislocation densities in the nitride layers grown on sapphire. This investigation focused on defect reduction in GaN epitaxial thin layer was investigated as a function of processing variables. The microstructure changes from threading dislocations normal to the basal plane to stacking faults in the basal plane. The plan-view TEM and the corresponding selected-area diffraction patterns show that the film is single crystal and is aligned with a fixed epitaxial orientation to the substrate. The epitaxial relationship was found to be (0001)GaN∥(0001)Sap and [01-10]GaN∥[-12-10]Sap. This is equivalent to a 30° rotation in the basal (0001) plane. The film is found to contain a high density of stacking faults with average spacing 15 nm terminated by partial dislocations. The density of partial dislocations was estimated from plan-view TEM image to be 7×109 cm−2. The cross-section image of GaN film shows the density of stacking faults is highest in the vicinity of the interface and decreases markedly near the top of the layer. Inverted domain boundaries, which are almost perpendicular to the film surface, are also visible. The concentration of threading dislocation is relatively low (∼;2×108 cm−2), compared to misfit dislocations. The average distance between misfit dislocations was found to be 22 Å. Contrast modulations due to the strain near misfit dislocations are seen in high-resolution cross-sectional TCM micrograph of GaN/α-Al2O3 interface. This interface is sharp and does not contain any transitional layer. The interfacial region has a high density of Shockley and Frank partial dislocations. Mechanism of accommodation of tensile, sequence and tilt disorder through partial dislocation generation is discussed. In order to achieve low concentration of threading dislocations we need to establish favorable conditions for some stacking disorder in thin layers above the film-substrate interface region.

Temperature Dependent Stability of Stacking Fault in Highly Nitrogen-Doped 4H-SiC Crystals

2016 ◽  
Vol 858 ◽  
pp. 109-112
Author(s):  
Chisato Taniguchi ◽  
Aiko Ichimura ◽  
Noboru Ohtani ◽  
Masakazu Katsuno ◽  
Tatsuo Fujimoto ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Quantum Well ◽  
Double Layer ◽  
Basal Plane ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Carrier Distribution ◽  
Temperature Dependent ◽  
Nitrogen Doped ◽  
Proposed Model

The formation of basal plane stacking faults in highly nitrogen-doped 4H-SiC crystals was theoretically investigated. A novel theoretical model based on the so-called quantum well action (QWA) mechanism was proposed; the model considers several factors, which were overlooked in a previously proposed model, and explains well the annealing-induced formation of double layer Shockley-type stacking faults in highly nitrogen-doped 4H-SiC crystals. We further revised the model to consider the carrier distribution in the depletion regions adjacent to the stacking fault and were successful in explaining the shrinkage of stacking faults during annealing at even higher temperatures.

Three-dimensional reciprocal space mapping with a two-dimensional detector as a low-latency tool for investigating the influence of growth parameters on defects in semipolar GaN

2015 ◽  
Vol 48 (4) ◽  
pp. 1000-1010 ◽  
Author(s):  
Sondes Bauer ◽  
Sergey Lazarev ◽  
Martin Bauer ◽  
Tobias Meisch ◽  
Marian Caliebe ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Stacking Faults ◽  
Vapour Phase ◽  
Stacking Fault ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
Partial Dislocations ◽  
Semipolar Gan

A rapid nondestructive defect assessment and quantification method based on X-ray diffraction and three-dimensional reciprocal-space mapping has been established. A fast read-out two-dimensional detector with a high dynamic range of 20 bits, in combination with a powerful data analysis software package, is set up to provide fast feedback to crystal growers with the goal of supporting the development of reduced defect density GaN growth techniques. This would contribute strongly to the improvement of the crystal quality of epitaxial structures and therefore of optoelectronic properties. The method of normalized three-dimensional reciprocal-space mapping is found to be a reliable tool which shows clearly the influence of the parameters of the metal–organic vapour phase epitaxial and hydride vapour phase epitaxial (HVPE) growth methods on the extent of the diffuse scattering streak. This method enables determination of the basal stacking faults and an exploration of the presence of other types of defect such as partial dislocations and prismatic stacking faults. Three-dimensional reciprocal-space mapping is specifically used in the manuscript to determine basal stacking faults quantitatively and to discuss the presence of partial dislocations. This newly developed method has been applied to semipolar GaN structures grown on patterned sapphire substrates (PSSs). The fitting of the diffuse scattering intensity profiles along the stacking fault streaks with simulations based on a Monte Carlo approach has delivered an accurate determination of the basal plane stacking fault density. Three-dimensional reciprocal-space mapping is shown to be a method sensitive to the influence of crystallographic surface orientation on basal stacking fault densities during investigation of semipolar (11{\overline 2}2) GaN grown on anr-plane (1{\overline 1}02) PSS and semipolar (10{\overline 1}1) GaN grown on ann-plane (11{\overline 2}3) PSS. Moreover, the influence of HVPE overgrowth at reduced temperature on the quality of semipolar (11{\overline 2}2) GaN has been studied.

Overlapping Shockley/Frank Faults in 4H-SiC PiN Diodes

2006 ◽  
Vol 527-529 ◽  
pp. 383-386 ◽  
Author(s):  
Mark E. Twigg ◽  
Robert E. Stahlbush ◽  
Peter A. Losee ◽  
Can Hua Li ◽  
I. Bhat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Light Emission ◽  
Stacking Faults ◽  
Dark Field ◽  
Pin Diodes ◽  
Plan View ◽  
Planar Defects ◽  
Burgers Vector ◽  
Partial Dislocations ◽  
Transmission Electron

Using light emission imaging (LEI), we have determined that not all planar defects in 4H-SiC PiN diodes expand in response to bias. Accordingly, plan-view transmission electron microscopy (TEM) observations of these diodes indicate that these static planar defects are different in structure from the mobile stacking faults (SFs) that have been previously observed in 4H-SiC PiN diodes. Bright and dark field TEM observations reveal that such planar defects are bounded by partial dislocations, and that the SFs associated with these partials display both Frank and Shockley character. That is, the Burgers vector of such partial dislocations is 1/12<4-403>. For sessile Frank partial dislocations, glide is severely constrained by the need to inject either atoms or vacancies into the expanding faulted layer. Furthermore, these overlapping SFs are seen to be fundamentally different from other planar defects found in 4H-SiC.

Partial Dislocations and Stacking Faults in 4H-SiC PiN Diodes

2004 ◽  
Vol 457-460 ◽  
pp. 537-542 ◽  
Author(s):  
Mark E. Twigg ◽  
Robert E. Stahlbush ◽  
M. Fatemi ◽  
Steve Arthur ◽  
Jeffery B. Fedison ◽  
...  
Keyword(s):  
Stacking Faults ◽  
Pin Diodes ◽  
Partial Dislocations

Performance of Silicon Carbide PiN Diodes Fabricated on Basal Plane Dislocation-Free Epilayers

2006 ◽  
Vol 527-529 ◽  
pp. 371-374 ◽  
Author(s):  
Ze Hong Zhang ◽  
A.E. Grekov ◽  
Priyamvada Sadagopan ◽  
S.I. Maximenko ◽  
Tangali S. Sudarshan
Keyword(s):  
Basal Plane ◽  
Stacking Faults ◽  
Surface Damage ◽  
Induced Current ◽  
Pin Diodes ◽  
Current Stressing ◽  
Forward Current ◽  
Nucleation Sites ◽  
Basal Plane Dislocation ◽  
Electron Beam Induced Current

The nucleation sites of stacking faults (SFs) during forward current stress operation of 4H-SiC PiN diodes were investigated by the electron beam induced current (EBIC) mode of scanning electron microscopy (SEM), and the primary SF nucleation sites were found to be basal plane dislocations (BPDs). Damage created on the diode surface also acts as SF nucleation sites. By using a novel BPD-free SiC epilayer, and avoiding surface damage, PiN diodes were fabricated which did not exhibit SF formation under current stressing at 200A/cm2 for 3 hours.

Stacking Faults in Crystals

1968 ◽  
Vol 26 ◽  
pp. 250-251
Author(s):  
P. C. J. Gallagher
Keyword(s):  
Stacking Faults ◽  
Elastic Equilibrium ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Major Influence ◽  
Face Centered Cubic ◽  
Degree Of Dissociation ◽  
Partial Dislocations ◽  
Layer Structures ◽  
Face Centered

Stacking faults are an important substructural feature of many materials, and have been widely studied in layer structures (e.g. talc) and in crystals with hexagonal and face centered cubic structure. Particular emphasis has been placed on the study of faulted defects in f.c.c. alloys, since the width of the band of fault between dissociated partial dislocations has a major influence on mechanical properties.Under conditions of elastic equilibrium the degree of dissociation reflects the balance of the repulsive force between the partials bounding the fault, and the attractive force associated with the need to minimize the energy arising from the misfits in stacking sequence. Examples of two of the faulted defects which can be used to determine this stacking fault energy, Υ, are shown in Fig. 1. Intrinsically faulted extended nodes (as at A) have been widely used to determine Υ, and examples will be shown in several Cu and Ag base alloys of differing stacking fault energy. The defect at B contains both extrinsic and intrinsic faulting, and readily enables determination of both extrinsic and intrinsic fault energies.

Sign in / Sign up

Export Citation Format

Share Document