Bell Communications Research, Inc.

At&t Bell Laboratories

Bell Telephone Laboratories

Brian G Bagley

Jean-Marie Tarascon

David E Aspnes

William E Quinn

Robert B Marcus

Eli Yablonovitch

Arthur C Adams

Matthew Julius Andrejco

Thomas J Gmitter

Charles R Kurkjian

Tirunelveli S Ravi

A method of fabricating a self-aligned gated electron field emitter. An oxidation process forms an optimized, atomically sharp needle (18) in a silicon substrate (12). The needle and surrounding planar area are conformally coated with silicon dioxide (22). A dielectric layer (24) is deposited and planarized over the needle. The dielectric layer is then partially etched away so as to expose the coated needle. The silicon dioxide exposed on the needle is isotropically etched so as to undercut the dielectric layer. A gate metal is directionally deposited so as to form a gate layer (26) on the planar portions of the dielectric layer that is electrically isolated from the gate metal (28) deposited on the needle. The metal on the needle is anodically etched by applying the potential only to the silicon and not to the gate layer. Electro-plating may recoat the needle with another metal (30). The silicon substrate may be replaced by a glass substrate (42) on which is deposited a polysilicon or amorphous silicon layer (40). The invention allows the fabrication of an array of emitters with closely spaced gates over large areas and on inexpensive substrates.

Self-aligned gated electron field emitter

A method of forming an optical fiber. A solution (12) is prepared in which are dissolved both a ladder siloxane and one or more dopants which are to be incorporated into the final silica or silicate glass. The solution is drawn into the interior of a silica tube (10) and is left as a coating (26) on the inside wall. The solvent is evaporated, and the rigid coating is cured at 150.degree. C. The filling and curing process may be repeated for multiple layers. The cured coating is then oxidized and fused into doped silica. The resultant tube preform is collapsed and drawn into a fiber. The method allows the introduction of nearly arbitrary constituents into the silica, including glass-forming elements and low-level dopants. The core-cladding interface is improved if a layer of glass-forming soot particles (28) is first deposited and the liquid is soaked into and over the soot.

Method of forming a fiber preform with dopants dissolved in a liquid

A film of linear organosilsesquioxane polymer, or 'ladder' organosiloxane, coated upon the surface of a LiMn.sub.2 O.sub.4 secondary battery electrode 19 and cured to a glassy layer is subjected to plasma oxidation to remove pendant organic groups comprising the coated polymer. The resulting ultrathin silica separator layer 17 is replete with minute pores which take up and retain by capillarity a typical LiClO.sub.4 electrolyte solution. A counter-electrode 15 placed in intimate contact with the silica electrolyte element completes a secondary battery structure 10 in which lithium ions readily migrate through the electrolyte during repeated discharge/charge cycles without loss of element integrity or efficacy.

Silica electrolyte element for secondary lithium battery

A method is described for the preparation of superconducting compositions in the yttrium-barium-copper oxide system. The oxygen stoichiometry required to assure the superconducting state is attained by a either a thermal annealing process or by means of plasma oxidation.

Oxygen plasma treatment of yttrium barium copper oxide

A method of passivating GaAs and InGaAs by growing on the GaAs or InGaAs used for semiconducting devices a surface film of glassy As.sub.2 S.sub.3 which acts as a passivating layer. The film growth is preferably done by precipitating As.sub.2 S.sub.3 from a solution containing NH.sub.4 OH, so as to make it basic, and then annealing the precipitated film at a temperature between the glass transition temperature (200.degree. C.) and the melting point (315.degree. C.) of As.sub.2 S.sub.3.

Arsenic sulfide surface passivation of III-V semiconductors

A method for the preparation of silicate glasses of controlled index of refraction involves the thermal and/or plasma processing of organo-silicon polymers. Compositions so treated evidence a suppressed index of refraction which may subsequently be increased by sintering to yield a material uniquely suited for use in fiber optic devices.

Method for preparation of silicate glasses of controlled index of

A silica fiber coated with an organosilsesquioxane polymer guide light and evidences excellent mechanical integrity under adverse conditions of temperature and humidity. The polymer serves as a suitable coating and cladding for silica-based fibers designed for low fabrication cost fiber optic applications, as a replacement for plastic coatings on silica-based fibers, and as a water barrier for fiber applications in humid environments. The polymeric material described evidences characteristics which are superior for both polymeric coatings (acrylate) and claddings (linear siloxanes).

Glass fibers having organosilsesquioxane coatings and claddings

A multiwaveguide cable in which the waveguides have different overall lengths can be made by twisting the waveguides during cabling. Waveguides situated at the 'outside' of the cable will be longer than those on the 'inside'. Such cables can be used for generating pulses, as passive scanners, for time division multiplexing for equalizing frequency dispersion and for many standard delay functions. Also disclosed are multicore fibers.

Information transmission using dispersive optical channels

Information transmission using dispersive optical fibers

Layers of controllably dopable amorphous silicon and germanium can be produced by means of low pressure chemical vapor deposition, at a reaction temperature between about 450.degree. C. and about 630.degree. C., for Si, and between about 350.degree. C. and about 400.degree. C. for Ge, in an atmosphere comprising a Si-yielding or Ge-yielding precursor such as SiH.sub.4 or GeI.sub.4, at a pressure between about 0.05 Torr and about 0.7 Torr, preferably between about 0.2 and 0.4 Torr. For undoped Si and P-doped Si, the preferred temperature range is from about 550.degree. C. to about 630.degree. C., for B-doped Si, it is from about 480.degree. C. to about 540.degree. C. The material produced has a density in excess of 0.9 of the corresponding crystalline density, and contains less than 1 atomic percent of hydrogen. An advantageous doping method is addition of dopant-forming precursor, e.g., PH.sub.3 or B.sub.2 H.sub.6, to the atmosphere. The material produced can be transformed into high quality crystalline material, and has many device applications in amorphous form, e.g., in solar cells, vidicon tubes, photocopying, and in integrated circuits, either as a conductor or nonconductor. The layers produced show conformal step coverage.

Method for producing devices comprising high density amorphous silicon

It has been found that the dielectric function .epsilon.(.nu.) of materials is strongly dependent on the microstructure of the material, i.e., on the volume fractions that are crystalline, amorphous, and void, respectively. This sensitivity makes it possible to conveniently and nondestructively determine by optical methods, typically a form of spectroscopic ellipsometry, the microstructure of layers of material that are typically bounded by a free surface. The determination of actual volume fractions is made by fitting the result of a model calculation, typically in an effective medium approximation, to the measured dielectric function over an appropriate range of frequencies, e.g. frequencies corresponding to photon energies of approximately 1.5 eV-6 eV. Alternatively, the measured dielectric function, or selected features or functions thereof, can be compared to preselected standard values. In either case, if this is done in a manufacturing context then the information derived allows appropriate adjustment of some manufacturing parameter or step. This can for instance be done by means of in situ monitoring and feedback, or by means of measurements after completion of the deposition of the material, resulting in the ability to tailor subsequent processing steps to the actually existing material state. The method is applicable to dielectrics, doped and undoped semiconductors, and to metals.

Growing community of inventors

Watchung, NJ, United States of America

Brian G Bagley