A5085804402- Silicon Carbide Semiconductor Technologies
- Silicon and Solar Cell Technologies
- Thin-Film Transistor Technologies
- GaN-based semiconductor devices and materials
- Semiconductor materials and interfaces
- Semiconductor materials and devices
- Advanced Surface Polishing Techniques
- Advanced ceramic materials synthesis
- Advanced Semiconductor Detectors and Materials
- Metal and Thin Film Mechanics
- Chalcogenide Semiconductor Thin Films
- Copper Interconnects and Reliability
- Integrated Circuits and Semiconductor Failure Analysis
- Acoustic Wave Resonator Technologies
- Semiconductor Quantum Structures and Devices
- Electron and X-Ray Spectroscopy Techniques
- X-ray Diffraction in Crystallography
- ZnO doping and properties
- Crystallization and Solubility Studies
- Microstructure and mechanical properties
- Ga2O3 and related materials
- Boron and Carbon Nanomaterials Research
- Diamond and Carbon-based Materials Research
- Aluminum Alloy Microstructure Properties
- Quantum Dots Synthesis And Properties
Stony Brook University
2016-2025
State University of New York
2004-2023
St. Jude Children's Research Hospital
2022-2023
Mapp Biopharmaceutical (United States)
2022
Nagoya University
2021
Corning (United States)
2010
Universitat Rovira i Virgili
2009
University of Maryland, Baltimore County
2009
Brookhaven National Laboratory
2006-2007
Kansas State University
2005
We describe the fabrication and characterization of tungsten oxide nanofibers using electrospinning technique sol-gel chemistry. Tungsten isopropoxide precursor was incorporated into poly(vinyl acetate)(PVAc)/DMF solutions electrospun to form composite nanofibers. The as-spun were subsequently calcinated obtain pure with controllable diameters around 100 nm. SEM TEM utilized investigate structure morphology before after calcination. relationship between solution concentration ceramic...
Given the high-density (/spl sim/10/sup 4/ cm/sup -2/) of elementary screw dislocations (Burgers vector=1c with no hollow core) in commercial SiC wafers and epilayers, all large current (>1 A) power devices will likely contain for foreseeable future. It is therefore important to ascertain electrical impact these defects, particularly high-field vertical device topologies where expected enable performance improvements solid-state high-power systems. This paper compares dc-measured...
The boron phosphide (BP) semiconductor has many remarkable features, including high thermal neutron capture cross section of the 10B isotope, making it attractive for detection applications. Effective and efficient require BP to also have crystal quality with optimum electrical properties. Here, we present heteroepitaxial growth films on a superior aluminum nitride(0001)/sapphire substrate by chemical vapor deposition. effect process variables crystalline morphological properties was...
A model is presented for a possible mechanism of screw dislocation (including micropipe) nucleation in silicon carbide. The based on the observation micropipe at sites foreign material inclusions using synchrotron white beam x-ray topography and transmission optical microscopy. It shown that incorporation inclusion into growing crystal can lead to deformation protruding ledge which constitutes overgrowing layer. Accommodation this lattice leads production pairs opposite sign dislocations...
The generation and evolution of defects in 4H–SiC p-n junctions due to carrier injection under forward bias have been investigated by synchrotron white beam x-ray topography, electroluminescence imaging, KOH etching. are Shockley stacking faults with rhombic or triangular shapes bound partial dislocation loops lines along Peierls valleys (〈11-20〉) the intersection basal plane containing fault diode surface. Burgers vector all bounding partials was 1/3〈10-10〉-type. Among six possible types...
A set of powerful x-ray imaging techniques using white-beam synchrotron radiation have been developed and applied to clearly reveal map micropipes in SiC crystals at a “magnified” level. The experimental results the corresponding simulations demonstrate explicitly that are pure superscrew dislocations (SSDs). Moreover, these provide accurate descriptions detailed structure SSDs, including spatial distribution strain fields, magnitudes Burgers vectors, dislocation senses, surface relaxation effects.
A strategy to reduce the density of threading dislocations (TDs) in AlN epilayers grown on sapphire substrates is reported. The TDs experience a redirection their line orientation which found coincide with imposed increases both V/III ratio and overall flux rate leading formation an internal subinterface delineated by changes dislocation orientation. Threading either large kinks then redirect into or form dipole half loops via annihilation redirected segments opposite sign latter significant...
Synchrotron white-beam X-ray topography studies, in conjunction with Nomarski optical microscopy, have been carried out on 6H-SiC single crystals grown by the sublimation physical vapour transport technique. Two kinds of dislocations were observed using topography: exhibiting bimodal images various widths and line directions approximately parallel to (0001) axis confined basal plane, which appear emanated from former dislocations. The larger image width found hollow cores, known as...
We describe a relatively simple, reliable, and reproducible preparation technique, the precursor oxidation process, for making VO2 films with strong semiconductor-to-metal phase transition. Sputter-deposited metal V were oxidized in situ deposition chamber 2.5–7h at 370–415°C 0.2Torr O2 to form 22–220nm VO2. The strength [resistivity ratio, RR=ρS∕ρM] sharpness (hysteresis width ΔTC) of T-dependent hysteretic transition our most immediate relevant quality indicators. In 200-nm-range films,...
Recent research has demonstrated the effectiveness of “aspect ratio trapping” technique for eliminating threading dislocations in Ge grown selectively submicron trenches on Si substrates. In this letter, analysis mechanisms by which dislocation elimination is achieved been carried out. Detailed transmission electron microscopy studies reveal that facets, when formed early growth process, play a dominant role determining configurations films. These are shown to behave as “growth...
The current state-of-the-art of wide bandgap (WBG) semiconductor material technology is reviewed for the manufacturing high-performance and reliable power electronics switching devices. In particular, silicon carbide (SiC) gallium nitride (GaN) device technologies are evaluated when compared to conventional For commercial applications above 400 volts, SiC stands out as a viable near-term opportunity especially single-chip ratings in excess 20 amps. voltage below 900 volts smaller currents...
The growth of large diameter silicon carbide (SiC) crystals produced by the physical vapor transport (PVT) method is outlined. Methods to increase crystal diameters, and turn these into substrates that are ready for epitaxial SiC or other non homogeneous layers discussed. We review present status 150 mm 200 substrate quality at Cree, Inc. in terms crystallinity, dislocation density as well final surface quality.
A short review is presented of the various synchrotron white beam x-ray topography (SWBXT) imaging techniques developed for characterization silicon carbide (SiC) crystals and thin films. These techniques, including back-reflection topography, reticulography, transmission a set section are demonstrated to be particularly powerful hollow-core screw dislocations (micropipes) closed-core threading dislocations, as well other defects, in SiC. The geometrical diffraction mechanism commonly...
A kinematic (geometrical) diffraction simulation model has been developed to provide understanding of direct dislocation images on synchrotron white-beam X-ray topographs, and successfully applied illustrate the contrast formation mechanisms involved in micropipe-related superscrew dislocations silicon carbide crystals. The coincidence simulations with features images, recorded using a series topography techniques, shows that this is capable revealing detailed behavior highly distorted...
Observations have been made, using synchrotron white beam x-ray topography, of stacking faults in 4H–SiC with fault vectors kind 1/6⟨202¯3⟩. A mechanism has postulated for their formation which involves overgrowth by a macrostep the surface outcrop c-axis threading screw dislocation, two c/2-height spiral steps, several dislocations Burgers vector c+a, c-height protrude onto terrace between c/2-risers. Such processes deflect basal plane, enabling them to exit crystal and thereby providing...
White beam or transmission Laue X-ray topography is a now widely used imaging technique, especially in association with synchrotron sources. Several images may be recorded simultaneously, potentially allowing for direct defect characterization. Owing, however, to projection conditions, these suffer from rather large geometrical distortions. This paper presents general treatment of the projective properties topographs. Specific results applicable simple but frequently utilized...
Abstract Dislocation-grain-boundary (GB) interactions in polycrystalline ice Ih during creep have been studied situ using synchrotron X-ray topography. The basal slip system with the highest Schmid factor was found to be most active whereas GB orientation relative loading direction seemed unimportant. GBs act both as effective sources of lattice dislocations and strong obstacles dislocation motion. observations revealed pile-up formation upon relaxation after unloading. Non-basal segments...