Electrical Properties of Dislocations and Boundaries in Semiconductors

1982 ◽  
Vol 14 ◽  
Author(s):  
Hans J. Queisser
Keyword(s):  
Electrical Properties ◽  
Imaging Techniques ◽  
Experimental Methods ◽  
Actual Situation ◽  
Dangling Bond ◽  
Semiconductor Crystals ◽  
Capacitance Spectroscopy ◽  
Electron Microscopes ◽  
Regular Arrays ◽  
Electronic Behavior

ABSTRACTSimple models have been suggested to predict electronic properties of lattice defects in semiconductor crystals: dislocations ought to act via the acceptor character of dangling bonds, and small-angle grain boundaries ought to consist of regular arrays of dislocations. The actual situation in most semiconductors is, however, much more complicated. The observed electrical effects of dislocations do not confirm the dangling-bond concept, they are affected by dissociation and reconstruction. There appear to be differences between straight and kinked dislocations. Dislocations owe much of their electronic behavior to clouds and precipitates of impurities; oxygen in silicon plays a significant role. This review summarizes the present status of experimental methods and results, including luminescence and capacitance spectroscopy as well as mapping and imaging techniques using electron-microscopes.

Twin boundary structure of a Y-Ba-Cu-O superconductor

1989 ◽  
Vol 47 ◽  
pp. 168-169
Author(s):  
Yimei Zhu ◽  
Masaki Suenaga ◽  
R. L. Sabatini ◽  
Youwen Xu
Keyword(s):  
Twin Boundary ◽  
Fine Particles ◽  
Imaging Techniques ◽  
Fine Powder ◽  
Orthorhombic Phase ◽  
Boundary Structure ◽  
Crystallographic Axis ◽  
System A ◽  
High Resolution Structure ◽  
Electron Microscopes

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.

Effect of Nitrogen Doping on the Growth of 4H Polytype on the 6H-SiC Seed by PVT Method

2012 ◽  
Vol 717-720 ◽  
pp. 29-32 ◽  
Author(s):  
Emil Tymicki ◽  
Krzysztof Grasza ◽  
Katarzyna Racka ◽  
Tadeusz Łukasiewicz ◽  
Miroslaw Piersa ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Nitrogen Doping ◽  
Experimental Methods ◽  
Structural And Electrical Properties

In this work results of nitrogen doping in the amount of 0 vol.%, 3 vol.% and 10 vol.% on the growth of the 4H polytype on the 6H-SiC seed are presented. SiC crystals grown by PVT method on the (000-1) C-face of 6H seeds using the open seed backside design have been investigated. Structural and electrical properties of the crystals were studied by different experimental methods.

scholarly journals Ghost imaging with electron microscopy inspired, non-orthogonal phase masks

2021 ◽  
Author(s):  
Akhil Kallepalli ◽  
Daan Stellinga ◽  
Ming-Jie Sun ◽  
Richard Bowman ◽  
Enzo Rotunno ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
High Energy ◽  
Reconstruction Method ◽  
Ghost Imaging ◽  
Light Modulator ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Electron Microscopes ◽  
Energy Processes

Abstract Transmission electron microscopes (TEM) achieve high resolution imaging by raster scanning a focused beam of electrons over the sample and measuring the transmission to form an image. While a TEM can achieve a much higher resolution than optical microscopes, they face challenges of damage to samples during the high energy processes involved. Here, we explore the possibility of applying computational ghost imaging techniques adapted from the optical regime to reduce the total, required illumination intensity. The technological lack of the equivalent high-resolution, optical spatial light modulator for electrons means that a different approach needs to be pursued. Using the optical equivalent, we show that a simple six-needle charged device to modulate the illuminating beam, alongside a novel reconstruction method to handle the resulting highly non-orthogonal patterns, is capable of producing images comparable in quality to a raster-scanned approach with much lower peak intensity.

New Model for Local H-Atom Bonding Re-Arrangements Associated with the Staebler-Wronski Effect in a-Si:H and a-Si:H-Based Alloys

1994 ◽  
Vol 336 ◽  
Author(s):  
G. Lucovsky ◽  
M.J. Williams ◽  
S.M. Cho ◽  
Z. Jing ◽  
J.L. Whitten
Keyword(s):  
Electrical Properties ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Nearest Neighbor ◽  
Electron Trapping ◽  
Dangling Bond ◽  
Atom Source ◽  
Staebler Wronski Effect ◽  
Induced Changes ◽  
Trapped Electron

ABSTRACTMany photoelectronic properties of a-Si,N:H alloys prepared by remote PECVD (RPECVD) from two N-atom source gases - N2 and NH3 - are the same; however, the photo-induced changes in the electrical properties in alloys with -2.1 eV bandgaps are ∼3 to 5 times greater in alloys deposited from NH3, which display Si-NH, as well as SiH bonding. Based on this result, we show that bonding groups important in the Staebler-Wronski effect include (i) ≡SiH, and nearest-neighbor (ii) ≡Si-NH-Sis and/or ≡Si-O-Sis in which the respective N and O-atoms make H-bonds with the sSiH group. The model, based on ab-initio calculations, includes a H-exchange reaction in which trapping of photo-generated holes promotes a transfer of the H-atom from the ^SiH group to a nearest-neighbor ≡Si-NH-Si≡ creating (i) a Si-dangling bond (Si*) and (ii) a Metastable (≡Si-NH2-Si≡) + group. Calculations indicate that neutral (≡Si-NH2≡Sis) ° is unstable, so that relaxation of (≡Si-NH2-Si≡) + groups can occur by trapping of a thermally-released (trapped) electron during a post-light-soaking thermal-anneal. The same type of model is developed for hole/electron trapping-induced H-atom transfer between ≡SiH and ≡Si-0-Si≡ groups in other a-Si:H Materials.

Characterization of 6H-SiC Single Crystals Grown by PVT Method Using Different Source Materials and Open or Closed Seed Backside

2009 ◽  
Vol 615-617 ◽  
pp. 19-22 ◽  
Author(s):  
Katarzyna Racka ◽  
Emil Tymicki ◽  
Marcin Raczkiewicz ◽  
Krzysztof Grasza ◽  
Michal Kozubal ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Single Crystals ◽  
Room Temperature ◽  
Experimental Methods ◽  
Room Temperature Resistivity ◽  
P Type ◽  
Source Materials ◽  
Type Crystal ◽  
Temperature Resistivity

n- and p-type 6H-SiC single crystals grown by PVT method using different charge materials – poly-SiC sinter or fresh SiC powder – have been studied. An open or closed seed backside during the growth processes have been applied. In the former, a distinct decrease backside etching of the seed was observed. Crystals have been extensively characterized with respect to their purity, quality and electrical properties using complex experimental methods. For the n-type boule an axially and radially homogeneous resistivity ~0.11 cm at 300 K was observed. Electrical properties of the p-type crystal, i.e., high room-temperature resistivity of 239 cm, were affected by compensation effects between residual donors (nitrogen and oxygen) and acceptors (mainly boron).

TEM/FIB Technical Solutions to Electron Beam Induced Radiation Damage to Low K/Ultra Low K Dielectrics in Semiconductor Failure Analysis

2012 ◽  
Author(s):  
Liu Binghai ◽  
Chen Ye ◽  
Mo Zhiqiang ◽  
Zhao Si Ping ◽  
Wang Chue Yuin ◽  
...  
Keyword(s):  
Electron Beam ◽  
Sample Preparation ◽  
Failure Analysis ◽  
Radiation Damage ◽  
Low Dose ◽  
Imaging Techniques ◽  
Single Beam ◽  
Electron Microscopes ◽  
Technical Solutions ◽  
Low K

Abstract Electron-beam induced radiation damage can give rise to large structural collapse and deformation of low k and ultra low k IMD in semiconductor devices, posing great challenges for failure analysis by electron microscopes. Such radiation damage has been frequently observed during both sample preparation by dual-beam FIB and TEM imaging. To minimize radiation damage, in this work we performed systematic studies on every possible failure analysis step that could introduce radiation damage, i.e., pre-FIB sample preparation, FIB milling, and TEM imaging. Based on these studies, we utilized comprehensive technical solutions to radiation damage by each failure analysis step, i.e., low-dose/low-kV FIB and low-dose TEM techniques. We propose and utilize the low-dose TEM imaging techniques on conventional TEM tools without using low-dose imaging control interface/software. With these new methodologies or techniques, the electron-beam induced radiation damage to ultra low k IMD has been successfully minimized, and the combination of single-beam FIB milling and low-dose TEM imaging techniques can reduce structure collapse and shrinkage to almost zero.

Comparative Study on the Impurities Content of Hydrogenated Transformer Oil under Static Condition

2011 ◽  
Vol 421 ◽  
pp. 129-135
Author(s):  
Yi Hua Qian ◽  
Yi Bin Huang ◽  
Qiang Fu ◽  
Hai Yan Wu ◽  
Zhen Sheng Zhong
Keyword(s):  
Experimental Data ◽  
Electrical Properties ◽  
Interfacial Tension ◽  
Comparative Study ◽  
Sulfur Content ◽  
Static Condition ◽  
Experimental Methods ◽  
Transformer Oil ◽  
Total Acidity ◽  
Particulate Contamination

The impurities content of domestic hydrogenated transformer oil and three kinds of naphthenic transformer oil had been determined by using the specified experimental methods. A series of experimental data had been obtained, including mechanical impurities, particulate contamination, corrosive sulfur, sulfur content, total acidity and interfacial tension. The impurities content of four kinds of transformer oil were compared with the quality indicators of transformer oil on GB/T7595-2008. The results showed that the impurities content of the former was not so satisfying although it had excellent electrical properties and the technology needed to be improved.

Data Acquisition for Specimen-Specific Computational Models

2009 ◽  
Author(s):  
Mariana E. Kersh ◽  
Heidi-Lynn Ploeg ◽  
Mike Shin ◽  
Eik Siggelkow ◽  
Marc Muenchinger
Keyword(s):  
Experimental Data ◽  
Computational Models ◽  
Mechanical Response ◽  
Imaging Techniques ◽  
Experimental Methods ◽  
Joint Models ◽  
Validation Data ◽  
Computing Power ◽  
Validation Of Models ◽  
Joint Biomechanics

Advances in medical imaging techniques and computing power have allowed for the creation of sophisticated joint models that include anatomical soft tissue geometries. However the models still require experimental data of the joint’s mechanical response in order to validate the model and accurately predict joint biomechanics. Experimental methods to acquire data of the joint’s mechanical response have a long history in biomechanics [1], but it has been found that the validation of models [2] based on previously collected experimental data has been difficult because of the large inter-specimen variability. A shift, therefore, has taken place emphasizing the development of specimen specific models. Our aim was to develop a method by which the mechanical response of the knee could be measured and used as input and validation data for a specimen specific computational model.

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