Patents Represented by Attorney, Agent or Law Firm Glen E. Books
  • Patent number: 5288572
    Abstract: The formation of latent images in photoresist can be monitored during exposure without spurious images by directing a pulsed beam of monochromatic light onto a region of the layer being exposed and selectively detecting the diffracted light. Peak formation in the normalized diffracted intensity versus time curve indicates optimal exposure of the resist.
    Type: Grant
    Filed: March 26, 1992
    Date of Patent: February 22, 1994
    Assignee: AT&T Laboratories
    Inventors: Konstantinos P. Giapis, Richard A. Gottscho, Christian A. Green
  • Patent number: 5285086
    Abstract: Semiconductor devices having a low density of dislocation defects can be formed of epitaxial layers grown on defective or misfit substrates by making the thickness of the epitaxial layer sufficiently large in comparison to the maximum lateral dimension. With sufficient thickness, threading dislocations arising from the interface will exit the sides of the epitaxial structure and not reach the upper surface. Using this approach, one can fabricate integral gallium arsenide on silicon optoelectronic devices and parallel processing circuits. One can also improve the yield of lasers and photodetectors.
    Type: Grant
    Filed: June 18, 1992
    Date of Patent: February 8, 1994
    Assignee: AT&T Bell Laboratories
    Inventor: Eugene A. Fitzgerald, Jr.
  • Patent number: 5281542
    Abstract: Using ion implant isolation, applicant has demonstrated a substantially planar quantum well photodetector free of exposed mesa side walls and having performance characteristics comparable with conventional mesa QWIPs. The planar photodetector presents a topography well suited for integration with other electronic components and the planar structure can be scaled to diameters much smaller than are typically useful in the conventional bonded devices.
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: January 25, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Sanghee P. Hui, Shin-Shem Pei
  • Patent number: 5277752
    Abstract: In accordance with the invention, a plasma generated within a plasma confinement chamber for use in manufacturing semiconductor devices is controlled by monitoring both the neutral gas pressure P and the neutral gas temperature T. The process parameters P and T are then adjusted to control P/T.sup.n. In a preferred embodiment the pressure is adjusted to maintain P/T constant by adjusting the gas flow rate or the outlet pumping speed. The result is a plasma exhibiting enhanced stability over prolonged periods of time.
    Type: Grant
    Filed: October 19, 1992
    Date of Patent: January 11, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Eray S. Aydil, Richard A. Gottscho, Jeffrey A. Gregus, Mark A. Jarnyk
  • Patent number: 5276746
    Abstract: In accordance with the invention an integrated optic device useful as a low level polarization independent optical tap comprises a pair of optical waveguides intersecting at an angle of 10.degree.-25.degree. to provide a tap signal in the range minus 20 dB to minus 60 dB. In a preferred embodiment for use in a passive repeater for undersea cable, the device comprises fiber-matching waveguides of phosphorus silicate glass on an oxide covered silicon substrate with a boron and phosphorus silicate cladding. The waveguides preferably intersect at an angle of 13.degree.-16.degree.. The preferred repeater further comprises a 3 dB coupler for averaging the power provided by two external pumping sources and a pair of wavelength division multiplexers for applying the pumping power to the outputs of the tap.
    Type: Grant
    Filed: June 24, 1992
    Date of Patent: January 4, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Renen Adar, Charles H. Henry, Rudolf F. Kazarinov, Michele A. Milbrodt
  • Patent number: 5275687
    Abstract: In accordance with the invention, a contaminated III-V semiconductor surface is cleaned by the sequential steps of exposure to hydrogen plasma, chemical etching in chlorine and annealing in vacuum. In a preferred embodiment, a semiconductor of the gallium arsenide family is subjected to hydrogen plasma in an ECR system for 20-120 minutes, then, without breaking vacuum, subjected to a Cl.sub.2 chemical etch at 250.degree. C.-450.degree. C. for 1-5 minutes. Again, without breaking vacuum, the semiconductor is annealed at 200.degree. C.-600.degree. C. for 5-15 minutes. To obtain good surface reconstruction, annealing preferably takes place at a temperature 300.degree. C. or above. The semiconductor surface thus processed is atomically smooth and sufficiently clean to permit regrowth of a high quality epitaxial layer.
    Type: Grant
    Filed: November 20, 1992
    Date of Patent: January 4, 1994
    Assignee: AT&T Bell Laboratories
    Inventors: Kent D. Choquette, Robert S. Freund, Minghwei Hong, Joseph P. Mannaerts
  • Patent number: 5252434
    Abstract: In accordance with the invention, a workpiece is provided with a sloped surface of predetermined slope by the steps of: a) coating the workpiece with resist, b) exposing the resist-coated workpiece to activating radiation which varies linearly in the direction of slope, c) developing the exposed resist, and d) etching the resulting structure to form an intaglio pattern in the workpiece surface. In a preferred embodiment, the resist is positive working photoresist and the exposure is through an exposure mask comprising a sequence of triangles having their bases aligned along a line defining the higher edge of a downward sloped region and their apices extending along a line defining the lower edge. After development, the structure is reactively ion etched.
    Type: Grant
    Filed: August 26, 1992
    Date of Patent: October 12, 1993
    Assignee: AT&T Bell Laboratories
    Inventor: Greg E. Blonder
  • Patent number: 5245454
    Abstract: Applicant has discovered a method for microembossing reflector surfaces with controlled reflecting patterns too small to be resolved by the unaided eye but capable of providing controlled reflection characteristics superior to uncontrolled random deformation. The result is a microtextured reflector of having dispersion characteristics of enhanced uniformity and a display device which can be read over an enhanced range of viewing angles. Specifically, a reflector in accordance with the invention comprises a base plane and a pattern of microelements having maximum lateral dimensions less than 125 micrometers and smooth, continuous mold-formed surfaces arising from the base plane. Such a reflector surface can be made using a master formed by covering a substrate with photoresist, exposing the resist to define a pattern of microelements having maximum lateral dimensions less than about 125 micrometers and heating the substrate to partially melt the resist elements thereby obtaining smooth-surfaced microelements.
    Type: Grant
    Filed: December 31, 1991
    Date of Patent: September 14, 1993
    Assignee: AT&T Bell Laboratories
    Inventor: Greg E. Blonder
  • Patent number: 5241190
    Abstract: Quantum wells are typically formed in a semiconductor body comprising alternating barrier layers and quantum well layers. A longitudinal dimension can be defined along the layers, and the body has a pair of surfaces on opposite sides of the set of layers. In accordance with the invention, apparatus for contacting a plurality of layers within the semiconductor body comprises a first contact for contacting a plurality of wells at a first position and a second contact for contacting the wells at a second position longitudinally spaced apart from the first contact. A first electrode overlies and extends across the wells on one surface at a longitudinal position intermediate the two contacts, and second electrode on the opposite surface overlies and extends across the wells intermediate the contacts. By applying appropriate voltages to the electrodes, one or more of the underlying quantum wells can be selectively depleted locally of carriers, thereby controlling which of the wells can conduct between the contacts.
    Type: Grant
    Filed: October 17, 1991
    Date of Patent: August 31, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: James P. Eisenstein, Loren N. Pfeiffer
  • Patent number: 5239744
    Abstract: Multilayer magnetic components can be made with reduced cracking and magnetic degradation by forming layers having patterns of magnetic and insulating regions separated by regions that are removable during sintering. Advantageously, when the layers are stacked, layers of removable material are also disposed between magnetic regions and insulating regions so as to produce upon sintering a magnetic core within an insulating body wherein the core is substantially completely surrounded by a thin layer of free space.
    Type: Grant
    Filed: January 9, 1992
    Date of Patent: August 31, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Debra A. Fleming, David W. Johnson, Jr., Warren W. Rhodes, Apurba Roy, John Thomson, Jr.
  • Patent number: 5239521
    Abstract: A portable radio telephone device which is in the form of a wristwatch which is fastened to the user's wrist via a strap. The telephone device is comprised of two main components, a case and a strap. The case has a display and a transceiver. The strap or band has at least a top and a bottom layer which are attached to the case. The top layer of the band is releasable in the proximity where the case and strap meet. However, the top layer remains connected to the bottom layer of the strap by a pivotable hinge. The pivotable hinge is typically located opposite the case and permits the top layer to be rotated. The length of the top layer can be increased either by repositioning the case or having additional layers located beneath the top layer. The speaker is located on the end of the released top layer. The microphone is located on the band. When the top layer is released and rotated, the speaker is located in the palm of the user's hand and the microphone is positioned along the inside of the user's forearm.
    Type: Grant
    Filed: May 29, 1992
    Date of Patent: August 24, 1993
    Assignee: AT&T Bell Laboratories
    Inventor: Greg E. Blonder
  • Patent number: 5239193
    Abstract: An integrated photodiode is formed by providing a silicon substrate with a deep recessed tub in excess of about 20 microns, forming an isolated p-n junction on the peripheral tub surfaces, and selectively epitaxially filling the tub with intrinsic silicon. A desired monolithic integrated circuit is fabricated outside the tub periphery using conventional VLSI techniques. A photodiode electrode structure within the tub periphery can be fabricated at the same time as other monolithic circuit components are formed.
    Type: Grant
    Filed: May 11, 1992
    Date of Patent: August 24, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Janet L. Benton, Renuka P. Jindal, Ya-Hong Xie
  • Patent number: 5237637
    Abstract: Applicants have discovered that the conversion efficiency of doped glass optical second harmonic generators can be enhanced when the frequency .omega. of the fundamental beam or the frequency 2.omega. of the harmonic beam is chosen near the resonance frequency of an optical transition in the dopant. This resonant enhancement is demonstrated for Tm doped aluminosilicate glass fibers where tuning of the fundamental writing beam to a resonance frequency enhances the second harmonic output by a factor of 10.sup.3.
    Type: Grant
    Filed: June 29, 1992
    Date of Patent: August 17, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: David J. DiGiovanni, Denise M. Krol, Chandra M. Varma
  • Patent number: 5227006
    Abstract: In accordance with the invention, gallium-containing layers are grown by molecular beam processes using as an arsenic precursor a compound of the dialkylaminoarsenic family (DAAAs) such as tris-dimethylamino arsenic (DMAAs). In contrast to conventional arsenic sources, DAAAs act as carbon "getters". When DAAAs are used as an arsenic source, the DAAAs getter carbon impurities from the gallium source. Thus, for example, DAAAs can be used as an arsenic source in combination with TMG as a gallium source to selectively grow high purity or n-type layers of gallium arsenide at low temperatures below 600.degree. C. In addition DMAAs has been found to be an excellent cleaning agent for gallium arsenide materials.
    Type: Grant
    Filed: November 27, 1991
    Date of Patent: July 13, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Cammy R. Abernathy, Stephen J. Pearton, Fan Ren, Patrick W. Wisk
  • Patent number: 5224113
    Abstract: In accordance with the present invention a semiconductor laser is provided with a cavity having decreasing loss with increasing wavelength in order to reduce temperature dependence. Such decreasing loss canbe obtained by providing the laser cavity with reflecting means or gratings which favor longer wavelengths. Decreasing loss can be provided, for example, by provision of appropriate multilayer reflection coatings or by longitudinal gratings. The coatings advantageously have peak reflectivity centered at the lasing wavelength corresponding to maximum operating temperature. The result in long wavelength InGaAs lasers is an improvement in the threshold temperature coefficient from about 50K to about 85K. In addition, the improved lasers exhibited a decreased rate of quantum efficiency degradation with temperature.
    Type: Grant
    Filed: December 20, 1991
    Date of Patent: June 29, 1993
    Assignee: AT&T Bell Laboratories
    Inventor: Won-Tien Tsang
  • Patent number: 5223704
    Abstract: Using ion implant isolation, applicant has demonstrated a substantially planar quantum well photodetector free of exposed mesa side walls and having performance characteristics comparable with conventional mesa QWIPs. The planar photodetector presents a topography well suited for integration with other electronic components and the planar structure can be scaled to diameters much smaller than are typically useful in the conventional bonded devices.
    Type: Grant
    Filed: March 31, 1992
    Date of Patent: June 29, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Sanghee P. Hui, Shin-Shem Pei
  • Patent number: 5221306
    Abstract: The transverse cross section of a body is modified by the steps of: a) determining the extent to which the body has material in excess of a desired shape at a plurality of points, b) exposing the body to a local heat source having a temperature sufficiently high to remove material from the surface of the body, and c) moving the surface of the body in relation to the source at a speed which decreases in regions where the body has material in excess of the desired shape so as to remove more material from such regions than from other regions. In a preferred embodiment, the body is an optical fiber preform, the local heat source is the fireball of a plasma torch, and the body is moved relative to the torch by rotating the preform at a controllable angular velocity while the torch is translated along the length of the preform.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: June 22, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: James W. Fleming, Jr., Adolph H. Moesle, Jr., Fred P. Partus
  • Patent number: 5221413
    Abstract: The present invention is predicated upon the discovery by applicants that by growing germanium-silicon alloy at high temperatures in excess of about 850.degree. C. and increasing the germanium content at a gradient of less than about 25% per micrometer, one can grow on silicon large area heterostructures of graded Ge.sub.x Si.sub.1-x alloy having a low level of threading dislocation defects. With low concentrations of germanium 0.10.ltoreq..times..ltoreq.0.50), the heterolayer can be used as a substrate for growing strained layer silicon devices such as MODFETS. With high concentrations of Ge (0.65.ltoreq..times..ltoreq.1.00) the heterolayer can be used on silicon substrates as a buffer layer for indium gallium phosphide devices such as light emitting diodes and lasers. At concentrations of pure germanium (X=1.00), the heterolayer can be used for GaAs or GaAs/AlGaAs devices.
    Type: Grant
    Filed: April 24, 1991
    Date of Patent: June 22, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Daniel Brasen, Eugene A. Fitzgerald, Jr., Martin L. Green, Ya-Hong Xie
  • Patent number: 5219772
    Abstract: The present invention is a method for making field effect devices, such as a field effect transistors, having ultrashort gate lengths so low as five hundred angstroms or less. In accordance with the invention the gate structure is grown vertically on a substrate by thin film deposition so that the length dimension of the gate is perpendicular to a major surface of the substrate. An edge of the gate-containing substrate is exposed, and the structure comprising the source, drain and channel is grown on the edge. Using this approach, field effect devices with precisely controlled gate lengths of less than 100 angstroms are achievable. Moreover the active regions of the device can be immersed within semiconductor material so that surface properties do not deteriorate device performance.
    Type: Grant
    Filed: August 15, 1991
    Date of Patent: June 15, 1993
    Assignee: AT&T Bell Laboratories
    Inventors: Kirk W. Baldwin, Loren N. Pfeiffer, Horst L. Stormer, Kenneth W. West
  • Patent number: 5212702
    Abstract: The present applicant has discovered that one can make a surface emitting laser with enhanced operating characteristics by etching away the outer reflector stack peripheral to the intended active area and protecting the reflector stack mesa remaining over the active area by in situ metalization in high vacuum. The active area can be isolated, as by ion implantation, providing an electrical path through the active region free of the outer reflector stack. The result is a surface emitting laser having reduced series resistance. The device lases at lower voltage and provides an enhanced intensity of optical output as compared with conventional planar devices.
    Type: Grant
    Filed: March 25, 1992
    Date of Patent: May 18, 1993
    Assignee: AT&T Bell Laboratories
    Inventor: Kent D. Choquette