Multifunctional single‐crystal tellurium core multimaterial fiber via thermal drawing and laser recrystallization

Author(s):  
Bin Han ◽  
Qianhang Luo ◽  
Pengyu Zhang ◽  
Ting Zhang ◽  
Guowu Tang ◽  
...  
1984 ◽  
Vol 35 ◽  
Author(s):  
J.P. Colinge

ABSTRACTThere are various methods for producing device-worthy Silicon-on-Insulator films, most, however, are unsuitable for fabrication of 3D integrated structures. The laser recrystallization technique is currently the only one which has produced single-crystal devices for 3D ICs. Improvements on this technique have been such that defects such as grain boundaries can be localized and even eliminated. High speed CMOS circuits with VLSI features have been realized as well as new devices which take advantage of the 3D arrangement of vertically integrated structures. Although 3D integration is still in the early stages of development, it has already opened up new perspectives for applications such as high speed circuits, dense memories, and sensors.


1980 ◽  
Vol 1 ◽  
Author(s):  
Rajiv R. Shah ◽  
D. Lloyd Crosthwait

ABSTRACTLarge crystals of silicon were obtained via pulsed laser annealing of thinfilms of fine grain CVD polycrystalline silicon. These films were analyzed using a novel technique that provides rapid feedback of crystallographic and defect information. The technique uses very shallow angle metallurgical sections in conjunction with chemical decoration and scanning electron microscopy and results in excellent depth resolution (<10 nm) across large spatial distances (>100 μm). The technique was used to reveal conversion of very large areas (≈ 1 mm 2) of polysilicon films deposited on silicon into single crystal film, albeit with point defects, without requiring the melt depth to reach the polysilicon/silicon interface. A gradual transition from single crystal to increasingly polycrystalline material was observed going from top to bottom of the initially uniform polycrystalline film depending on the pulse energy used. Polysilicon on top of an oxide layer, on the other hand, transforms into large (≈ 10 μm) single crystals with grain boundaries penetrating the entire polysilicon film thickness. These experimental results shed new light on two very important questions: (1) Is laser annealing entirely an epitaxial process or is it strongly influenced by the thermal properties of the underlying substrate, and (2) Whether substantial regrowth of polysilicon requires equilibrium thermodynamics.


1982 ◽  
Vol 13 ◽  
Author(s):  
P. Zorabedian ◽  
C.I. Drowley ◽  
T.I. Kamins ◽  
T.R. Cass

ABSTRACTA shaped laser beam has been used for laterally seeded recrystallization of polysilicon films over oxide. Direct maps of the shaped-beam intensity distribution in the wafer plane are correlated with the grain structure of the recrystallized polysilicon. Using 60% overlapping of shaped-beam scans along <100> directions, we have obtained seeded areas one mm wide and 50 to 500μm long. These consist of 40μm-wide adjacent single-crystal strips regularly separated by low-angle grain boundaries extending laterally away from the seed openings. The spacing between grain boundaries is equal to the scan spacing, providing a means for controlling the location of grain boundaries in otherwise defect-free, single-crystal films.


Author(s):  
Akira Tanaka ◽  
David F. Harling

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.


Author(s):  
L. E. Murr ◽  
G. Wong

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.


Author(s):  
D. J. Barber ◽  
R. G. Evans

Manganese (II) oxide, MnO, in common with CoO, NiO and FeO, possesses the NaCl structure and shows antiferromagnetism below its Neel point, Tn∼ 122 K. However, the defect chemistry of the four oxides is different and the magnetic structures are not identical. The non-stoichiometry in MnO2 small (∼2%) and below the Tn the spins lie in (111) planes. Previous work reported observations of magnetic features in CoO and NiO. The aim of our work was to find explanations for certain resonance results on antiferromagnetic MnO.Foils of single crystal MnO were prepared from shaped discs by dissolution in a mixture of HCl and HNO3. Optical microscopy revealed that the etch-pitted foils contained cruciform-shaped precipitates, often thick and proud of the surface but red-colored when optically transparent (MnO is green). Electron diffraction and probe microanalysis indicated that the precipitates were Mn2O3, in contrast with recent findings of Co3O4 in CoO.


Author(s):  
J. M. Galbraith ◽  
L. E. Murr ◽  
A. L. Stevens

Uniaxial compression tests and hydrostatic tests at pressures up to 27 kbars have been performed to determine operating slip systems in single crystal and polycrystal1ine beryllium. A recent study has been made of wave propagation in single crystal beryllium by shock loading to selectively activate various slip systems, and this has been followed by a study of wave propagation and spallation in textured, polycrystal1ine beryllium. An alteration in the X-ray diffraction pattern has been noted after shock loading, but this alteration has not yet been correlated with any structural change occurring during shock loading of polycrystal1ine beryllium.This study is being conducted in an effort to characterize the effects of shock loading on textured, polycrystal1ine beryllium. Samples were fabricated from a billet of Kawecki-Berylco hot pressed HP-10 beryllium.


Author(s):  
G. G. Hembree ◽  
M. A. Otooni ◽  
J. M. Cowley

The formation of oxide structures on single crystal films of metals has been investigated using the REMEDIE system (for Reflection Electron Microscopy and Electron Diffraction at Intermediate Energies) (1). Using this instrument scanning images can be obtained with a 5 to 15keV incident electron beam by collecting either secondary or diffracted electrons from the crystal surface (2). It is particularly suited to studies of the present sort where the surface reactions are strongly related to surface morphology and crystal defects and the growth of reaction products is inhomogeneous and not adequately described in terms of a single parameter. Observation of the samples has also been made by reflection electron diffraction, reflection electron microscopy and replication techniques in a JEM-100B electron microscope.A thin single crystal film of copper, epitaxially grown on NaCl of (100) orientation, was repositioned on a large copper single crystal of (111) orientation.


Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.


Author(s):  
Z.L. Wang

An experimental technique for performing electron holography using a non-FEG, non-biprism transmission electron microscope (TEM) has been introduced by Ru et al. A double stacked specimens, one being a single crystal foil and the other the specimen, are loaded in the normal specimen position in TEM. The single crystal, which is placed onto the specimen, is responsible to produce two beams that are equivalent to two virtual coherent sources illuminating the specimen beneath, thus, permitting electron holography of the specimen. In this paper, the imaging theory of this technique is described. Procedures are introduced for digitally reconstructing the holograms.


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