Abstract: Described are semiconductor heterostructures incorporating a metal layer. Devices based on the heterostructures are described, as are techniques for preparing the heterostructures. Specific embodiments wherein the metal layer is a metal silicide are detailed, and hot electron devices using this structure are analyzed briefly.

Abstract: The spreading of liquids, e.g., an epoxy resin, on a surface can be prevented or reduced if an inhibitor is added to the liquid. Inhibitors according to the invention have the generic formula [CX.sub.3 --(CY.sub.2).sub.n ].sub.N --R, where X is H or F, Y is H, F, or Cl, n is a number from about 1 to about 12, R is a carboxylic acid, an amide, a substituted amide, an amine, an alcohol, or an ester functionality, and N is 1, 2, or 3 if R is an alcohol or amine functionality, and 1 otherwise. The inhibitor typically has substantial solubility in at least one of the constituents of the liquid, and the liquid typically contains between about 0.05% and about 5% by weight of the inhibitor. Preferred inhibitors are perfluorooctanoic acid and 1H, 1H-pentadecafluorooctyl amine.

Abstract: The low temperature method for depositing multiconstituent material on a substrate uses at least two ballistic particle streams that are caused to intersect in a volume of space proximate to the substrate. One particle stream, the "gas" stream, comprises excited neutral particles, and the other particle stream, the "metal" stream, consists substantially of a particle species capable of chemically reacting with the excited neutrals. The excited neutrals are typically produced in a RF-generated plasma or by means of photon excitation, the source of the metal stream is typically an evaporator or a Knudsen cell. Charged particles can be removed from the gas stream by means of magnetic and/or electric fields, and their removal typically advantageously affects the electrical properties of the deposits.

Abstract: The use of induced electromagnetic field enhancement to improve chemical processing is disclosed. Shape, image and resonant polarizability phenomena are used to obtain regions of increased field intensities where atomic and/or molecular interactions are advantageously affected to yield improved or increased chemical processing.

Abstract: Fibers are coated with two (or more) layers. A first coating liquid is applied by an applicator having a die that provides for the formation of a gap between the die and the first coated layer. A second die is located at the exit of the first die, with the second coating liquid flowing onto the fiber through a relatively narrow clearance between the first and second dies. The clearance is formed by die surfaces perpendicular to the fiber axis. This second die also provides for a gap, so that the second layer is applied at a "free surface" at the point of contact with the first coated layer. This approach eliminates turbulence and coating nonuniformities associated with prior art multiple coating techniques.

Abstract: Multifilament bundles are impregnated with an ultraviolet curable resin to form a composite material suitable for use as a strength member in cables and other applications. The inventive coatings obtain good wetting of the filaments, allowing rapid penetration into the roving or yarn. A much faster coating and curing operation is obtained as compared to prior art methods. Fiberglass strength members made by this technique are especially advantageous for use in optical fiber cables where high strength and a low thermal coefficient of expansion are desired, as well as nonconductivity to protect against lightning strikes.

Abstract: The method for growing heteroepitaxial multiconstituent material on a substrate comprises deposition of a thin disordered layer of a "template-forming" material, i.e., material containing at least one constituent of the multiconstituent material to be grown, and differing in chemical composition from at least the substrate material, on the substrate surface at a relatively low deposition temperature, raising the substrate temperature to an intermediate transformation temperature, thereby causing the template-forming material to undergo a reaction that results in formation of "template" material, typically material having substantially the same composition as the multiconstituent material to be grown. Onto the thus formed template layer is then deposited the material for the epitaxial multiconstituent layer. This general process is exemplified by the growth of NiSi.sub.2 on a Si substrate, by first depositing at room temperature about 18.ANG.

Abstract: A composite contact material for light-duty electrical contacts is formed by combining, typically by powder-metallurgical techniques, a matrix metal and particles of a conductive material that is typically harder and more corrosion resistant than the matrix metal, and by removing, in a differential material removal step, some of the matrix metal from a surface of the composite, thereby producing a "sandpaper" surface with a substantial number of the particles projecting by a substantial amount above the matrix metal surface. Typical matrix metals are copper, copper alloys, or nickel, and typical particle materials are metals such as Ru, Re, Os, and intermetallics, oxides, borides, nitrides, carbides, silicides, and phosphides of such metals as Al, Ti, Ni, Nb, Mo, Ru, Ta, W, Re, or Os. Particle size is typically between about 0.1 .mu.m and 100 .mu.m, preferably less than 10 .mu.m, and the particle volume fraction is typically between about 1% and 50%, preferably between 5% and 30%.

Abstract: Fibers are coated with two (or more) layers. A first coating liquid is applied by an applicator having a die that provides for the formation of a gap between the die and the first coated layer. A second die is located at the exit of the first die, with the second coating liquid flowing onto the fiber through a relatively narrow clearance between the first and second dies. The clearance is formed by die surfaces perpendicular to the fiber axis. This second die also provides for a gap, so that the second layer is applied at a "free surface" at the point of contact with the first coated layer. This approach eliminates turbulence and coating nonuniformities associated with prior art multiple coating techniques.

Abstract: A method for changing Josephson device parameters, e.g., the critical current of a Josephson junction. The method comprises incorporating doping material into the device, or part of the device, followed by a light anneal. Exemplary dopants include In, Sn, Sb, Te, Bi, Hg, Mg, Li, Cd, Na and Ta, with In, Sn, and Sb being preferred dopants for changing the critical current of a Josephson junction having a Pb-containing counter electrode. The dopant can be incorporated into the device by in-diffusion after deposition onto the surface, by ion implantation, or by any other convenient method. The amount of dopant required is typically small. For example, deposition of a Sn layer of 0.05 nm effective thickness onto the 200 nm thick Pb-Sb(1.5 wt. %) counter electrode of a cross-type Josephson junction, and annealing at 80.degree. C. for about 3 hours, resulted in an increase in the critical current of the junction by a factor of about 2.5.

Abstract: The application pertains to fiberguide systems comprising signal sources having center wavelengths near an absorption peak in the loss spectrum of the fiber, with the systems having a link length of several km, preferably at least 5 km. The resulting "filtering" of the signal can be used advantageously. For instance, the repeater spacing of a LED-based multimode system can be increased if fiberguide having an absorption peak of appropriate strength located above the minimum chromatic dispersion wavelength of the fiber is used, and if the LED center wavelength is chosen to exceed that wavelength by a small amount. In particular, in silica-rich fiberguide, absorption peaks due to OH typically occur at about 1.24 .mu.m and 1.39 .mu.m, and the wavelength of minimum chromatic dispersion can be about 1.3 .mu.m. In such systems according to the invention, the total fiber loss at 1.39 .mu.m is typically at least about 0.

Abstract: The inventive multimode fiber has total loss at an operating wavelength of at least about 0.8 db/km, typically not more than 5 db/km. At least 0.3 db/km, preferably 0.5 db/km, of the loss is due to the presence in the fiber of radially nonuniformly distributed attenuation centers, with the concentration of the centers differing by at least about 10% between the concentration minimum and the maximum. The resulting differential mode attenuation can lead to fiber having larger bandwidth than analogous fiber without differential attenuation. Preferred distributions of attenuation centers have the concentration maximum either at or near the fiber axis, or at or near the core/clad interface. Preferred attenuation centers are absorbers, with OH being a preferred absorber.

Abstract: Improvements in the lateral recrystallization of semiconductor material on buried insulator are disclosed. In particular, in the zone-melting process applied to seeded Si, it is found that scanning the molten zone in a [110] direction can result in substantially subboundary-free recrystallized material. Furthermore, appropriate patterning of the capping layer, to provide means for accommodating the volume change attending solidification of the semiconductor material, can result in significant decrease of defect density in laterally recrystallized semiconductor material on insulator. Especially advantageous results are produced when combining the improvements.

Abstract: A helical layer on a cable core produces a zero torque response when the lay angle is chosen according to the inventive method. Previously, two helical layers having opposite lay angles have been used to obtain a zero torque response. Lightguide cables having a metallic helical armor layer, for example, advantageously utilize the present technique, which reduces the tendency of the cable to kink.

Abstract: A simple, inexpensive, and reliable technique for substantially preventing the unwanted formation of a surface guiding layer during manufacture of light-guiding structures in LiNbO.sub.3 and LiTaO.sub.3 substrates is disclosed. The technique involves addition of an effective amount of a gaseous hydrogen donor to the processing atmosphere during high-temperature processing. A particularly convenient hydrogen donor is water vapor, which can be added to the atmosphere by, for instance, bubbling of the feed gas through a water column. A partial pressure of more than about 9 Torr of H.sub.2 O has been found effective in the practice of the technique.

Abstract: The invention pertains to W-profile single-mode silica-based optical fiberguide, and to communication systems employing these fiberguide. Such guides can be designed to have large bandwidth over a wide wavelength region, and, in particular, to have minimal chromatic dispersion at two different wavelengths, e.g., about 1.3 .mu.m and about 1.55 .mu.m, the wavelengths of loss minima in silica. Disclosed are ranges of fiber parameters that can yield these and other advantageous fiberguide characteristics. In particular, in fibers according to the invention the difference between core and outer cladding refractive index is between about 0.1% and 0.4% of the outer cladding index, the difference between the inner cladding and the outer cladding index is between about 1 times and about 3 times the difference between core and outer cladding, the core radius is between about 0.5 and 0.8 times the outer radius of the inner cladding, and the outer radius of the inner cladding is at least about 5 .mu.m.

Abstract: This invention involves optical fiber which supports essentially only a single guided mode, perhaps degenerate, at the transmission wavelength, usually between 0.6 and 1.7 microns. The index of refraction of the core material is graded in the radial direction so as to yield an optical fiber with very low total dispersion and therefore high bandwidth. Specific embodiments include, in addition to the low dispersion characteristic, improved field confinement, and therefore permit lower clad-to-core ratios then heretofore believed practical. Additional advantages which accrue as a result of the greater field confinement include lower cabling, microbending, and curvature-induced losses.

Abstract: The data transmission rate link length product of monomode fiberguide telecommunication systems can be increased above values possible in "linear" systems by appropriate use of the non-linear dependence of the fiber refractive index on electric field. In particular, selecting the appropriate pulse peak power and center wavelength can result in creation of a soliton, i.e., a pulse capable of substantially dispersionless transmission. The center wavelength is to be close to, but larger than, the wavelength of zero first-order chromatic dispersion of the fiberguide, and the latter wavelength is to be within the anomalous dispersion regime of the fiberguide. Criteria for determining the appropriate peak power, center wavelength, fiber loss, and minimum link length, as well as the asymptotic pulse width and soliton spread due to the power loss in the fiber are given, and facilitate design of a system according to the invention.

Abstract: Method for adjusting the value of birefringence in predetermined sections of waveguides in integrated optics devices fabricated in optically anisotropic substrates such as monocrystalline LiNbO.sub.3 or LiTaO.sub.3. The inventive method comprises in combination methods for changing both refractive indices in a first volume of the substrate, such as, for instance, ion implantation or metal in-diffusion, thereby creating an optical waveguide for both TE and TM modes of radiation, and methods for further changing one of the indices in a second volume of the substrate, without proportionally changing the other index in the second volume, such as, for instance, Li out-diffusion or ion exchange. In a typical application, the first volume comprises waveguiding regions, including the section in which the birefringence is to be adjusted, and the second volume also includes that waveguide section.

Abstract: Disclosed are magnetically soft ferritic multiphase Fe-Ni alloys having a Ni content in the range of about 4 to about 16 weight percent, devices containing a body fabricated from such alloys, and method for heat treating such body. Appropriate heat treatment comprises a low-temperature anneal in the two-phase (.alpha.+.gamma.) region of the Fe-Ni phase diagram, and typically results in improved magnetic properties. In particular, alloys according to the invention having x weight percent of Ni have a maximum permeability .mu..sub.m at least as large as 1.5[25(16-x).sup.2 ]G/Oe. The alloys typically also have a coercive field H.sub.c at most as large as 0.7[0.65(1+0.6x)]Oe, a saturation induction B.sub.s of at least about 20 kG, a maximum incremental permeability .DELTA..mu., measured with an applied a.c. field of about 0.005 Oe, of at least about 150 G/Oe, and a yield strength to 0.2 percent offset of at least about 40 10.sup.3 psi, with all the material properties measured at room temperature.