Patents Represented by Attorney Arthur A. Smith, Jr.
  • Patent number: 4378629
    Abstract: A layer of material such as the metal base of a transistor is embedded in single crystal. A layer of the material with small, uniformly dimensioned and uniformly spaced openings is formed on a single crystal substrate, and the single crystal is grown from the exposed portions of the substrate over the layer of material. For best results, the layer of material to be embedded is deposited relative to the crystal orientation to provide a much greater rate of crystal growth laterally across the layer than away from the crystal substrate. The method is particularly useful in fabricating a permeable base transistor having slits formed in the metal base layer. An integrated circuit can be fabricated by forming a pattern of conductive material on a single crystal, that pattern having continuous regions which inhibit further crystal growth and narrow regions or regions having openings therein which permit lateral crystal growth across those regions.
    Type: Grant
    Filed: August 10, 1979
    Date of Patent: April 5, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: Carl O. Bozler, Gary D. Alley, William T. Lindley, R. Allen Murphy
  • Patent number: 4379020
    Abstract: A process for forming large-grain polycrystalline films from amorphous films for use as photovoltaic devices. The process operates on the amorphous film and uses the driving force inherent to the transition from the amorphous state to the crystalline state as the force which drives the grain growth process. The resultant polycrystalline film is characterized by a grain size that is greater than the thickness of the film.A thin amorphous film is deposited on a substrate. The formation of a plurality of crystalline embryos is induced in the amorphous film at predetermined spaced apart locations and nucleation is inhibited elsewhere in the film. The crystalline embryos are caused to grow in the amorphous film, without further nucleation occurring in the film, until the growth of the embryos is halted by imgingement on adjacently growing embryos. The process is applicable to both batch and continuous processing techniques.
    Type: Grant
    Filed: October 16, 1981
    Date of Patent: April 5, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: Andreas M. Glaeser, John S. Haggerty, Stephen C. Danforth
  • Patent number: 4377595
    Abstract: The level of norepinephrine in neuronal synapses is regulated in order to treat depression by administering a neutral amino acid composition to a human wherein an increased brain level of norepinephrine is effected when the composition contains increased amounts of tyrosine and/or phenylalanine. Increased or decreased brain levels of serotonin are obtained when the amino acid composition contains increased or decreased amounts of tryptophan.The neutral amino acid composition can be administered alone or concomitantly with a drug which increases or decreases noradrenergic neurotransmission.
    Type: Grant
    Filed: May 29, 1980
    Date of Patent: March 22, 1983
    Assignee: Massachusetts Institute of Technology
    Inventor: Richard J. Wurtman
  • Patent number: 4376285
    Abstract: An optoelectronic switch has been formed from a semi-insulating substrate of indium phosphide doped with a deep level impurity and disposed intermediate a microstrip transmission line. One conductor of the transmission line has a small gap in its metallization. Upon illumination of the gap by laser pulses which are absorbed near the semiconductor surface, a photogenerated electron-hole plasma forms thereby providing a conducting path across the gap turning the switch "on."A process of fabricating the switch is described, an important feature of which is a heat-treatment process which improves the response time of the switch to .about.50 picoseconds. Another important part of the invention is the formation of an optically semi-transparent metallic film at the gap surface. This provides greater efficiency in the coupling of light into the device at the gap while at the same time maintaining a short electronically non-conductive gap and thus a relatively low ON-state impedance for the switch.
    Type: Grant
    Filed: June 23, 1980
    Date of Patent: March 8, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: Frederick J. Leonberger, Frederick J. O'Donnell
  • Patent number: 4376228
    Abstract: Improvements in solar cells based upon low cost semiconductors, such as amorphous silicon, are disclosed. The improved solar cells of this invention have ultrathin active semiconductor layers having a thickness between 0.1 t.sub..alpha. and L.sub.m wherein t.sub..alpha. is the solar spectrum absorption length and L.sub.m is the diffusion length for photogenerated minority charge carriers in the active layer. The back surface reflector has a solar spectrum reflectivity of 70% or greater, so that incident energy not absorbed in a direct pass through the active layer is reflected for another pass. The most preferred embodiment of the cells described herein are shaped to have a light-trapping structure so that light makes multiple passes through the thin semiconductor layers.
    Type: Grant
    Filed: July 16, 1979
    Date of Patent: March 8, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: John C. C. Fan, Carl O. Bozler
  • Patent number: 4373023
    Abstract: Blood containing heparin and treated extracorporeally is contacted with immobilized heparinase prior to being reintroduced into the patient.
    Type: Grant
    Filed: October 14, 1980
    Date of Patent: February 8, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: Robert S. Langer, Robert Linhardt, Charles L. Cooney, Parrish M. Galliher, Margaret M. Flanagan, Michael D. Klein
  • Patent number: 4372791
    Abstract: Double-heterostructure (DH) diode lasers based upon very thin epitaxial layers of Ga.sub.x In.sub.1-x As.sub.y P.sub.1-y grown on and lattice-matched to oriented InP substrates are disclosed. A preferred method for fabricating such lasers involves the successive growth, on an InP substrate, of an InP buffer layer, the GaInAsP active layer and an InP top barrier layer using liquid phase epitaxy techniques to grow these layers from supercooled solutions. Stripe geometry lasers can be fabricated from these materials which emit in the 1.1-1.3 .mu.m range and are capable of cw operation for extended periods at room temperature.
    Type: Grant
    Filed: August 28, 1981
    Date of Patent: February 8, 1983
    Assignee: Massachusetts Institute of Technology
    Inventor: Jaw J. Hsieh
  • Patent number: 4372996
    Abstract: A method including a novel bath is described for the nickeling of the aluminum pads of a chip, when either in die form or in wafer assembly. A near-neutral pH immersion zinc bath is used to cover the aluminum with zinc, which is followed by immersion in an electroless boron-nickel solution for nickeling of the zinc. The method eliminates the need to isolate the chip silicon from the plating bath.
    Type: Grant
    Filed: September 7, 1979
    Date of Patent: February 8, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: Elis A. Guditz, Robert L. Burke
  • Patent number: 4371421
    Abstract: An improved method and apparatus for crystallizing amorphous or polycrystalline material is disclosed. In this invention, a material which is to be crystallized is formed on a substrate and single crystalline seed material is disposed adjacent and in contact with at least a portion of the material which is to be crystallized. A layer of material which serves as a "wetting agent" is then formed over the material to be crystallized. The structure thus formed is subjected to a heat treatment which melts the material being crystallized and when the material solidifies its crystalline structure is substantially epitaxial based on the seed material. The "wetting agent" layer serves to prevent deleterious balling up of the material during crystallization.
    Type: Grant
    Filed: April 16, 1981
    Date of Patent: February 1, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: John C. C. Fan, Michael W. Geis, Bor-Yeu Tsaur
  • Patent number: 4370194
    Abstract: Ordered liquids, or mesophases, are aligned by forming a structure on a substrate surface using a planar process of formation, the surface structure having a predetermined pattern, and applying a mesophase to the surface to substantially orient the molecules of the mesophase in accordance with the predetermined pattern. A liquid crystal display device can be made in which, in a preferred embodiment, the liquid crystal is confined between two substrates having oppositely disposed surfaces on which selected patterns of surface structures have been formed. The surface structures can be grating structures made of a conductive material, such as metal, which structures act to align the liquid crystal in accordance with the selected patterns, to polarize light passing through the surface structures, and to provide electrical contacts so that an electric signal applied thereto can produce an electric field in the region between the substrate surface structures.
    Type: Grant
    Filed: May 13, 1980
    Date of Patent: January 25, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: David C. Shaver, Henry I. Smith, Dale C. Flanders
  • Patent number: 4369363
    Abstract: Solid-state waveguide structures are disclosed to detect and/or encode very fast (picosecond) optical signals. The waveguides are appropriately configured to cause very fast signals to interact with interrogation or erasure pulses by a two photon absorption mechanism. The coincidence of the pulses in particular regions causes erasure and/or changes in the waveguide conductivity which can be measured conventionally by parallel circuitry.
    Type: Grant
    Filed: March 16, 1981
    Date of Patent: January 18, 1983
    Assignee: Massachusetts Institute of Technology
    Inventors: David Quint, George W. Pratt, Jr.
  • Patent number: 4369439
    Abstract: A position indicator or cursor is moved over a visual display in response to signals generated by corresponding movement of a keyboard relative to a fixed point on the surface supporting the keyboard.
    Type: Grant
    Filed: January 14, 1981
    Date of Patent: January 18, 1983
    Assignee: Massachusetts Institute of Technology
    Inventor: Michael S. Broos
  • Patent number: 4368480
    Abstract: Logic elements such as inverters, NAND-gates and NOR-gates that include charge-flow transistors and systems that include such logic elements, and oscillators that include such logic elements. A basic logic element includes a charge-flow transistor and a load element, in combination, the load element being connected to either the source or the drain of the charge-flow transistor.
    Type: Grant
    Filed: December 17, 1979
    Date of Patent: January 11, 1983
    Assignee: Massachusetts Institute of Technology
    Inventor: Stephen D. Senturia
  • Patent number: 4366338
    Abstract: A method of compensating grain boundaries or dislocations causing interstices to form particularly in polycrystalline semiconductor materials is disclosed which comprises selectively diffusing opposite impurity-type donor semiconductor material into the interstice to thereby reduce the conductivity of the interstice.
    Type: Grant
    Filed: January 9, 1981
    Date of Patent: December 28, 1982
    Assignee: Massachusetts Institute of Technology
    Inventors: George W. Turner, John C. C. Fan, Jack P. Salerno
  • Patent number: 4365005
    Abstract: A method of forming, by melt-spinning techniques, a laminated ribbon structure consisting, for example, of a semiconductor disposed on a metal ribbon substrate. The substrate may be 10-50 .mu.m thick and the semiconductor may be 10-50 .mu.m thick, for example; typically the ribbon width is about one millimeter to several centimeters.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: December 21, 1982
    Assignee: Massachusetts Institute of Technology
    Inventors: August F. Witt, Ramaswamy V. Raman
  • Patent number: 4365134
    Abstract: After measuring the bulk resistance the surface of high strength low alloy steel material is treated to form a high resistance coating on its surface. When resistance welding the material the coating permits weld formation without significant expulsion or excessive electrode force over a wide range of operating conditions.
    Type: Grant
    Filed: December 31, 1980
    Date of Patent: December 21, 1982
    Assignee: Massachusetts Institute of Technology
    Inventors: Thomas W. Eagar, Joseph G. Kaiser, Gregory J. Dunn
  • Patent number: 4361514
    Abstract: In accordance with this invention, it has been found that carbon and oxygen analogs of 6.beta.-aminopenicillanic acid and biologically active derivatives thereof can be formed from esters of 6-oxopenicillanic acid. For example, 6.beta.-phenoxyacetoxypenicillanic acid--an oxygen analog of penicillin V and 6.beta.-phenoxyacetylmethylpenicillanic acid--a carbon analog of penicillin V, may be formed from an ester of 6-oxopenicillanate. The ester of 6-oxopenicillanic acid is formed by a diiospropyl carbodiimide/dimethyl sulfoxide oxidation of the corresponding ester of 6.alpha.-hydroxypenicillanic acid. The oxygen analogs are formed by reducing the ester of 6-oxopenicillanic acid to the corresponding 6.beta.-hydroxypenicillanate and then forming the desired analog by acylation. The carbon analogs are formed by a Wittig reaction of the ester of 6-oxopenicillanic acid with a suitable acylmethylenetriphenylphosphorane followed by saturation of the newly formed double bond and removal of the protective ester group.
    Type: Grant
    Filed: February 17, 1981
    Date of Patent: November 30, 1982
    Assignee: Massachusetts Institute of Technology
    Inventors: John C. Sheehan, Young S. Lo
  • Patent number: 4361154
    Abstract: A method for establishing, in vivo, the strength of bone in a live being such as, for example, a horse. The method permits determination of the speed of travel of sound through the bone and the strength of the bone is assessed on the basis of said speed of travel.
    Type: Grant
    Filed: June 15, 1979
    Date of Patent: November 30, 1982
    Assignee: Massachusetts Institute of Technology
    Inventor: George W. Pratt, Jr.
  • Patent number: 4360586
    Abstract: Soft carbon-K X-rays (38) expose a PMMA photoresist (31) on an oxide layer (32) of a silicon substrate (33) through a parent mask (30) separated a distance S from the resist by a spacer (34) with the parent mask slits (12, 17) defining a spatial period p to establish an intensity pattern of period p/n at the photomask with S=p.sup.2 /n.lambda., where .lambda. is the wavelength of the incident radiation and .lambda.<p.
    Type: Grant
    Filed: April 14, 1980
    Date of Patent: November 23, 1982
    Assignee: Massachusetts Institute of Technology
    Inventors: Dale C. Flanders, Henry I. Smith
  • Patent number: 4358146
    Abstract: A release mechanism which is releasable from the direction of the load and requires that two levers be pulled in sequence and held from the direction of the load for release. Hook-up may be achieved manually with one hand.
    Type: Grant
    Filed: February 2, 1981
    Date of Patent: November 9, 1982
    Assignee: Massachusetts Institute of Technology
    Inventor: Clifford A. Goudey