Abstract: Optical fiber including a core and a clad suitable for use in wavelength division multiplex systems. The fiber can have an attenuation at 1550 nm less than 0.25 dB/km, a cut off wavelength of less than 1.40 .mu.m, and a dispersion slope less than 0.15 ps/(nm.sup.2 -km).

Abstract: Fabrication of sub-micron design rule integrated circuits entails imposition of patterning information, consisting of degree of scattering, on a projected scanning beam of accelerated electrons by means of a mask, imaging being dependent upon passage through a back focal plane filter including a plurality of apertures for selectively passing relatively unscattered electrons.

Abstract: Ringfield projection apparatus using x-ray radiation e.g. of 1.30 .ANG. wavelength is suitable for lithographic patterning in the fabrication of integrated circuits at design rules of 0.25 .mu.m and below. The design permits reduction from an enlarged mask as well as substantial throughput, the latter due to unexpectedly large slit width. Incorporation of a folding mirror improves fabrication expediency by moving the device being fabricated to the other side of the system from the mask.

Abstract: Fabrication of reflective masks, designed for use with x-ray delineating radiation in the construction of sub-micron devices, is expedited by use of a barrier layer intermediate the multilayer reflector and the absorber layer. The barrier is designed to reduce damage to the multilayer reflector during two stages of fabrication--during initial patterning and during subtractive or additive mask repair. Composition of the barrier is so chosen as to minimize such damage during its removal in baring of the reflector, and also as to have requisite stability in regions retained during mask life.

Abstract: Expedient fabrication of fine-featured integrated circuits entails aperture pattern delineation to produce a masking layer atop a semiconductor body followed by insertion within a controlled atmosphere chamber within which device-functional layered material is epitaxially grown within apertures. Critical, device-consequential properties of epitaxial material is assured by removal of a thin surface layer of material revealed during delineation. Such removal, sufficient to eliminate meaningful contamination and/or crystalline damage introduced during delineation, is of sufficiently small quantity as to be accommodated within the chamber. Under most circumstances, the controlled atmosphere is at reduced pressure as required for e.g. MOMBE epitaxial growth.

Abstract: Fabrication of submicron design rule large scale integrated circuits depends upon use of a strut-segmented mask with struts providing mechanical support to permit thinned mask segments consequently yielding improved resolution. "Stitching"--positioning of projected segment images to yield a satisfactory continuous image--is aided by lithographically defined skirts forming a continuous border within strut-supported segments.

Abstract: Fabrication of devices of micron and submicron minimum feature size is accomplished by lithographic processing involving a back focal plane filter. A particularly important fabrication approach depends upon mask patterns which produce images based on discrimination as between scattered and unscattered radiation by accelerated electrons. Use of such masks is of value as applied to scanning systems providing for dynamic correction of aberrations by physical movement of or field shaping of the objective lens to maintain the optical axis coincident with the scanning information-scanning beam.

Abstract: Magnetic circuit elements, e.g. for inclusion on circuit boards including one or more windings about a toroidal core are produced by joinder of mating sheets, one or both recessed to hold the core, and each containing partial windings. Joinder is by use of an anisotropically conducting adhesive layer. The layer is applied as an uncured thermosetting adhesive containing spherical conducting particles of such size and distribution as to statistically result in electrical completion of windings while avoiding turn-to-turn shorting.

Abstract: Lowered cost fabrication including preparation of large bodies of void-free, high-silica glass, depends upon gellation of an aqueous sol of colloidal silica particles, followed by drying and firing of such gel. Freedom from cracks in the dried gel is the consequence of included polymeric material which wets the particles. The polymeric material is removed by thermal decomposition attended upon temperature attained in firing.

Abstract: Distributed Bragg Reflectors of high efficacy based on alternating layers of large difference in refractive index are fabricated by epitaxial growth followed by etchant removal and back-filling to produce a structure in which alternation is between layers of retained epitaxially grown material and layers of back-filled material. Such reflectors may serve simply as mirrors or may be incorporated in a variety of devices including lasers, LEDs, detectors, optical switches in which the DBRs serve e.g. for cavitation.

Abstract: Imaging at sub-micron dimensions--at dimensions ordinarily thought to approximate those within diffraction limitations of the chosen imaging radiation--is expedited by use of a new category of phase masks. The new mask structure provides for phase shifting by use of waveguides. Waveguides of such dimensions, material, and spacing as to accommodate image resolution impairment, may consist of filled or unfilled apertures or of protuberances, all of constant length equal to the thickness of the mask layer in which constructed.

Abstract: Single GaAs quantum well or single GaAs active layer or single reverse interface structures with Al.sub.x Ga.sub.1-x As barrier layers have improved qualities when one or more narrow bandgap GaAs getter-smoothing layers, which are thin, are grown and are incorporated in the barrier layer before and in close proximity to the active layer.

Abstract: Separation between a magnetized member and a Type II superconducting member inherently manifestets stability in separation distance, in lateral direction and in attitude. Uses include levitation of fixed and moveable members as well as superconducting bearings.

Abstract: A carbon transmitter utilizes an electrode prepared by in situ reaction between substrate copper and introduced sulfur. Good surface adhesion between the resulting CuS layer and the substrate is assured by use of a two-phase cobalt/copper substrate.

Abstract: Ion beam lithography of particular interest in the fabrication of large-scale integrated circuits of unexpectedly increased throughput results from appropriate choice of (a) resist material and (b) ion species. Resist material, generally negative acting, is characterized by electron beam sensitivity inadequate for ordinary commercial electron beam lithography. The relevant characteristic responsible for inadequate electron beam sensitivity is the very characteristic responsible for enhanced ion sensitivity. Ion species, always of atomic number greater than that of proton, are dictated by the observation that sensitivity unexpectedly increases at a greater rate than predictable on traditional bases.

Abstract: A preform for fabrication of a glass fiber optical transmission line is prepared by chemical reaction of vapor ingredients within a glass tube. Reaction, which may be between chlorides or hydrides of, for example, silicon and germanium with oxygen, occurs preferentially within a constantly traversing hot zone. Flow rates and temperature are sufficient to result in glass formation in the form of particulate matter on the inner surface of the tube. This particulate matter deposits on the tube and is fused with each passage of the hot zone. Continuous rotation of the tube during processing permits attainment of higher temperatures within the heated zone without distortion of the tube.

Abstract: Optical fiber preforms are produced by means of a duplex hot zone, a section of which is defined by an r.f. generated plasma fire ball. The process operates within a tube with gaseous precursor material reacting within the hot zone to result in deposited material of the desired preform glass composition. A "smoothing" region within the hot zone is defined by tube surface at a temperature sufficiently elevated to consolidate any particulate material resulting from reaction. In some aspects, the disclosed procedures may be regarded as Modified Chemical Vapor Deposition. Commercial significance resides in significantly increased throughput of preforms and, consequently, in fiber.

Abstract: Etch rate in plasma-assisted etching is increased by inclusion of an additional oxidant. The oxidant increases consumption of unsaturates in the plasma to increase etchant species lifetime and to suppress polymer formation.

Abstract: A phase compatibile polymer blend serves as a radiation sensitive lithographic resist in the fabrication of circuits and circuit elements. Radiation sensitivity is due to inclusion of a "modifier". Resist properties, notably stability to agents and ambients to be masked are attributed largely to a second component, the "matrix polymer".In an exemplary embodiment in which the blend is positive acting, fabrication including dry processing is dependent upon use of a resist blend of a vapor developing polysulfone and a novolac. The novolac, inherently soluble in alkaline media is rendered insoluble in the blend. Radiation initiated depolymerization results in volatilization of the modifier to render the irradiated portions of the resist soluble in alkaline developers.Modifier may function in other manner; for example, it may undergo radiation initiated polymerization so as to insolubilize the blend in irradiated regions, so resulting in a negative acting resist.

Abstract: Lithographic patterning of particular interest in fabrication of integrated circuitry is based on the photoinduced migration of silver into germanium selenide or other glassy material of appropriate absorption cross section for the chosen actinic radiation. Resists which are negative-acting yield high resolution attributed to initial introduction of the silver in chemically combined form chosen so as to result in formation of a silver compound with a glass component with the compound serving as silver source. Removal of excess silver-containing material is engineered on the basis of the form of silver introduction and results in conversion to a water soluble form. Commercial use will likely be based on an embodiment in which the now developed patterned resist serves as a dry etching mask during delineation of a relatively thick underlying layer of organic material. This procedure is particularly advantageous for use on partially processed circuitry in which prior operations have resulted in surface steps.