Magnetic Field Detector Using Compound Semiconductor Material (e.g., Gaas, Insb, Etc.) Patents (Class 257/425)
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Patent number: 7019371Abstract: A current-in-plane magnetic sensor comprises a sensor stack including first and second layers of ferromagnetic material, a first nano-oxide layer positioned adjacent to the first layer of ferromagnetic material, and a layer of non-magnetic material positioned between the first and second layers of ferromagnetic material, wherein the thickness of the non-magnetic layer is selected to provide antiferromagnetic coupling between the first and second ferromagnetic layers, a magnetic field source for biasing the directions of magnetization of the first and second layers of ferromagnetic material in directions approximately 90° with respect to each other, a first lead connected to a first end of the sensor stack, and a second lead connected to a second end of the sensor stack. Disc drives that use the current-in-plane magnetic sensor are also included.Type: GrantFiled: January 26, 2004Date of Patent: March 28, 2006Assignee: Seagate Technology LLCInventor: Michael Allen Seigler
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Patent number: 6921953Abstract: The present invention seeks to reduce the amount of current required for a write operation by using a process for forming the read conductor within a recessed write conductor, the write conductor itself formed within a trench of an insulating layer. The present invention protects the MTJ from the voltages created by the write conductor by isolating the write conductor and enabling the reduction of current necessary to write a bit of information.Type: GrantFiled: April 9, 2003Date of Patent: July 26, 2005Assignee: Micron Technology, Inc.Inventor: James G. Deak
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Patent number: 6903429Abstract: A magnetic sensor device formed using SOI CMOS techniques includes a substrate, a silicon oxide layer and in some cases a plurality of gated regions. A first terminal is located between two innermost gated regions and supplies a supply voltage. A second and a third terminal, each of which is located between two adjacent gated regions other than the two innermost gated regions, output positive and negative Hall voltages. By appropriately controlling a bias voltage to the gated regions, small changes in a magnetic field induces larger currents in channel regions under the gated regions, which, in turn, results in detectable Hall voltages.Type: GrantFiled: April 15, 2003Date of Patent: June 7, 2005Assignee: Honeywell International, Inc.Inventors: Dale F. Berndt, Andrzej Peczalski, Eric E. Vogt, William F. Witcraft
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Patent number: 6879012Abstract: Ferromagnetic semiconductor-based compositions, systems and methods that enable studies of the dynamics and magnetoresistance of individual magnetic domain walls, and which provide enhanced magnetic switching effects relative to metallic ferromagnets. Aspects of the present invention are enabled by recent studies of the Giant Planar Hall effect (GPHE), and in particular GPHE in (Ga,Mn)As—based devices. The GPHE generally originates from macro- and micromagnetic phenomena involving single domain reversals. The GPHE-induced resistance change in multiterminal, micron-scale structures patterned from (Ga,Mn)As can be as large as about 100?, four orders of magnitude greater than analogous effects previously observed in metallic ferromagnets. Accordingly, recent data provide sufficient resolution to enable real-time observations of the nucleation and field-induced propagation of individual magnetic domain walls within such monocrystalline devices.Type: GrantFiled: June 23, 2003Date of Patent: April 12, 2005Assignees: The Regents of the University of California, California Institute of TechnologyInventors: Hongxing Tang, Michael L. Roukes, Roland K. Kawakami, David D. Awschalom
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Patent number: 6878979Abstract: A spin switch that can be driven with voltage. This spin switch includes the following: a ferromagnetic material; a magnetic semiconductor magnetically coupled to the ferromagnetic material; an antiferromagnetic material magnetically coupled to the magnetic semiconductor; and an electrode connected to the magnetic semiconductor via an insulator. A change in the electric potential of the electrode causes the magnetic semiconductor to make a reversible transition between a ferromagnetic state and a paramagnetic state. When the magnetic semiconductor is changed to the ferromagnetic state, the ferromagnetic material is magnetized in a predetermined direction due to the magnetic coupling with the magnetic semiconductor.Type: GrantFiled: January 18, 2002Date of Patent: April 12, 2005Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Nozomu Matsukawa, Masayoshi Hiramoto, Akihiro Odagawa, Mitsuo Satomi, Yasunari Sugita
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Patent number: 6867468Abstract: A magnetic memory array comprises a plurality of magnetic memory cells, a magnetic shielding disposed adjacent to at least one of the magnetic memory cells to reduce magnetic interference with respect to another of the magnetic memory cells, and an insulator disposed as to separate at least a portion of the magnetic shielding from the at least one magnetic memory cell. The magnetic shielding may be a magnetic shield layer, patterned magnetic shield materials, and/or magnetic particles embedded in the insulator.Type: GrantFiled: May 15, 2003Date of Patent: March 15, 2005Assignee: Hewlett-Packard Development Company, L.P.Inventors: Manish Sharma, Manoj Bhattacharyya
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Patent number: 6861718Abstract: A spin valve transistor, magnetic reproducing head including a spin valve transistor and a magnetic information storage system having the spin valve transistor. The spin valve transistor has a collector, a base formed on the collector, a tunnel barrier layer formed on the base and an emitter formed on the tunnel barrier layer. In one embodiment, the collector may have a first semiconductor layer of first composition and a second semiconductor layer of a different composition epitaxially grown. The base of the first spin valve transistor may be formed on the second semiconductor layer and have a magnetization pinned layer having a magnetization substantially fixed in an applied magnetic field, a nonmagnetic layer and a magnetization free layer having a magnetization free to rotate under the applied magnetic field. The emitter of a spin valve transistor of a second embodiment may include a semiconductor layer containing an oxide of transitional metal and contacting the tunnel barrier layer.Type: GrantFiled: March 28, 2003Date of Patent: March 1, 2005Assignee: Kabushiki Kaisha ToshibaInventors: Rie Sato, Koichi Mizushima
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Patent number: 6833599Abstract: A semiconductor magnetic sensor includes a semiconductor substrate, a source, a drain, a gate, and a carrier condensing means. The source and the drain are located in a surface of the substrate. One of the source and the drain includes adjoining two regions. The gate is located between the source and the drain for drawing minority carriers of the substrate to induce a channel, through which the carriers flow between the source and the drain to form a channel carrier current. The carriers flow into the two regions to form two regional carrier currents. The magnitude of a magnetic field where the sensor is placed is measured using the difference in quantity between the two regional carrier currents. The carrier condensing means locally increases carrier density in the channel carrier current in the proximity of an axis that passes between the two regions in order to increase the difference.Type: GrantFiled: February 27, 2003Date of Patent: December 21, 2004Assignee: Denso CorporationInventors: Inao Toyoda, Noboru Endo
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Patent number: 6787868Abstract: The invention provides integrated optical matching elements for use in integrated optical devices. The matching elements each comprise one or more lenses. The lenses may have low index contrast with the surrounding medium. Required dioptric power is achieved by using a train of lenses. Optical matching elements according to the invention can be used to enhance the optical coupling between channel waveguides and slab waveguides. The insertion loss of devices such as optical power splitters, optical couplers and arrayed waveguide grating routers can be reduced by incorporating optical matching elements according to the invention.Type: GrantFiled: September 25, 2001Date of Patent: September 7, 2004Assignee: Lightwave Microsystems CorporationInventors: Kenneth McGreer, Ming Yan, Brian McGinnis
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Patent number: 6756649Abstract: A modulator includes a voltage source, a first arrangement including first and second non-insulating layers configured such that a modulation voltage from the voltage source can be applied there across, and a second arrangement between the first and second non-insulating layers. The second arrangement includes a first amorphous layer configured such that a transport of electrons between the first and second non-insulating layers includes tunneling. The first arrangement further includes an antenna structure for absorbing part of an input radiation, while a remainder of the input radiation is reflected. The second arrangement cooperates with the first arrangement such that the antenna exhibits a first absorptivity, when a first modulation voltage is applied to the first arrangement, and exhibits a distinct, second absorptivity, when a second modulation voltage is applied, thereby causing the antenna to reflect a different amount of input radiation to an output as modulated radiation.Type: GrantFiled: January 20, 2003Date of Patent: June 29, 2004Assignee: The Regents of the University of ColoradoInventors: Garret Moddel, Blake J. Eliasson
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Publication number: 20040099919Abstract: The invention relates to an element, comprising a substrate with a surface roughness of less than 5 nm, with saturated bonds on the surface and an MPt3 film applied to at least one side of the substrate, with a magnetic anisotropy perpendicular to the plane of the film, with M=a metal of the 5th to 9th sub-group of the periodic table, nickel or gadolinium. The invention further relates to a method for production of the above and the use of said elements as a magnetic component, for example as a magnetic sensor or as a magneto-optical storage element.Type: ApplicationFiled: August 6, 2003Publication date: May 27, 2004Inventors: Gunter Schatz, Manfred Albrecht, Mireille Maret, Andreas Maier, Frank Treubel
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Patent number: 6734514Abstract: A metrological Hall effect sensor with sensitivity to temperature less than 250 ppm/° C. and with high Hall effect coefficient for temperatures greater than 200° C. formed in a multilayer structure comprising a thin active layer deposited on a substrate, wherein the substrate is made of monocrystalline silicon carbide (SiC), and wherein the thin active layer is made of a weakly type n-doped silicon carbide (SiC) semiconductor in the exhaustion regime.Type: GrantFiled: February 26, 2003Date of Patent: May 11, 2004Assignee: Centre National de la Recherche-Scientifique - CNRSInventors: Jean-Louis Robert, Julien Pernot, Jean Camassel, Sylvie Contreras
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Patent number: 6683359Abstract: A Hall effect device comprising: (a) an electrically-conductive layer or plate having a top surface: and (b) a ferromagnetic multilayer, where the conductive film or layer is composed of high mobility semiconductors. Also, a Hall effect device can be a device in which the Hall plate comprises an indium compound, germanium or mixtures thereof. The devices are useful for a variety of applications such as a memory element in a nonvolatile random access memory array (NRAM) and as a logic gate.Type: GrantFiled: June 21, 2002Date of Patent: January 27, 2004Assignee: The United States of America as represented by the Secretary of the NavyInventors: Mark B. Johnson, Gary A. Prinz
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Patent number: 6646315Abstract: A Hall effect device comprising: (a) an electrically-conductive layer or plate having a top surface; and (b) a ferromagnetic layer, where the conductive film or layer is composed of high mobility semiconductors. Also, a Hall effect device can have a ferromagnetic element that is a multilayer (e.g., a bilayer), and a device in which the Hall plate comprises an indium compound, germanium or mixtures thereof. The devices are useful for a variety of applications such as a memory element in a nonvolatile random access memory array (NRAM) and as a logic gate.Type: GrantFiled: April 22, 2002Date of Patent: November 11, 2003Assignee: The United States of America as represented by the Secretary of the NavyInventors: Mark B. Johnson, Gary A. Prinz
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Publication number: 20030197235Abstract: A Hall effect device comprising: (a) an electrically-conductive layer or plate having a top surface; and (b) a ferromagnetic layer, where the conductive film or layer is composed of high mobility semiconductors. Also, a Hall effect device can have a ferromagnetic element that is a multilayer (e.g., a bilayer), and a device in which the Hall plate comprises an indium compound, germanium or mixtures thereof. The devices are useful for a variety of applications such as a memory element in a nonvolatile random access memory array (NRAM) and as a logic gate.Type: ApplicationFiled: April 22, 2002Publication date: October 23, 2003Inventors: Mark B. Johnson, Gary A. Prinz
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Patent number: 6630882Abstract: Composite galvanomagnetic devices having a desired combination of properties in specific temperature ranges and magnetic field ranges and so combined that desired properties are provided over an extended temperature and magnetic field range. In practice this can be accomplished with a single die with layers of different properties. Particularly, the present invention addresses this method as related to magnetoresitors and Hall plates.Type: GrantFiled: July 21, 2000Date of Patent: October 7, 2003Assignee: Delphi Technologies, Inc.Inventors: Joseph Pierre Heremans, Dale Lee Partin, Thaddeus Schroeder
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Publication number: 20030179974Abstract: A device including an input port configured to receive an input signal is described. The device also includes an output port and a structure, which structure includes a tunneling junction connected with the input port and the output port. The tunneling junction is configured in a way (i) which provides electrons in a particular energy state within the structure, (ii) which produces surface plasmons in response to the input signal, (iii) which causes the structure to act as a waveguide for directing at least a portion of the surface plasmons along a predetermined path toward the output port such that the surface plasmons so directed interact with the electrons in a particular way, and (iv) which produces at the output port an output signal resulting from the particular interaction between the electrons and the surface plasmons.Type: ApplicationFiled: March 20, 2002Publication date: September 25, 2003Inventors: Michael J. Estes, Garret Moddel
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Patent number: 6621100Abstract: This invention relates to organic based spintronic devices, and electronic devices comprising them, including spin valves, spin tunnel junctions, spin transistors and spin light-emitting devices. New polymer-, organic- and molecular-based electronic devices in which the electron spin degree of freedom controls the electric current to enhance device performance. Polymer-, organic-, and molecular-based spintronic devices have enhanced functionality, ease of manufacture, are less costly than inorganic ones. The long spin coherence times due to the weak spin-orbit interaction of carbon and other low atomic number atoms that comprise organic materials make them ideal for exploiting the concepts of spin quantum devices. The hopping mechanism of charge transport that dominates in semiconducting polymers (vs. band transport in crystalline inorganic semiconductors) enhances spin-magneto sensitivity and reduces the expected power loss.Type: GrantFiled: October 26, 2001Date of Patent: September 16, 2003Assignee: The Ohio State UniversityInventors: Arthur J. Epstein, Vladimir N. Prigodin
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Publication number: 20030164530Abstract: A Hall effect sensor formed in a multilayer structure including a thin active layer deposited on a substrate, wherein the substrate is an insulating, semi-insulating or semiconductor material of type p− or n+, respectively, to electrically isolate the active layer of the substrate and wherein the active layer is a weakly doped semiconductor material of type n− or p− in an exhaustion regime.Type: ApplicationFiled: February 26, 2003Publication date: September 4, 2003Applicant: Centre National de la Recherche Scientifique - CNRS, a corporation of FranceInventors: Jean-Louis Robert, Julien Pernot, Jean Camassel, Sylvie Contreras
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Patent number: 6600202Abstract: A compact sensing apparatus having reduced cross section and methods are provided for sensing the magnitude and direction of an electrical or magnetic field. The compact sensing apparatus and method preferably provide one of two transducer orientations in relation to the direction of the field arranged in the sensor apparatus to provide the smallest possible cross section. The compact sensing apparatus preferably includes a plurality of mounting pins. Each of the plurality of mounting pins preferably includes a first pin portion and a second pin portion connected to the first pin portion at a predetermined angle. The predetermined angle is preferably less than 180 degrees and more preferably in the range of about 70-110 degrees.Type: GrantFiled: October 6, 2000Date of Patent: July 29, 2003Assignee: Wolff Controls CorporationInventors: Marshall E. Smith, Jr., Peter U. Wolff, Richard W. Stettler
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Publication number: 20030127700Abstract: A modulator includes a voltage source, a first arrangement including first and second non-insulating layers configured such that a modulation voltage from the voltage source can be applied there across, and a second arrangement between the first and second non-insulating layers. The second arrangement includes a first amorphous layer configured such that a transport of electrons between the first and second non-insulating layers includes tunneling. The first arrangement further includes an antenna structure for absorbing part of an input radiation, while a remainder of the input radiation is reflected. The second arrangement cooperates with the first arrangement such that the antenna exhibits a first absorptivity, when a first modulation voltage is applied to the first arrangement, and exhibits a distinct, second absorptivity, when a second modulation voltage is applied, thereby causing the antenna to reflect a different amount of input radiation to an output as modulated radiation.Type: ApplicationFiled: January 20, 2003Publication date: July 10, 2003Inventors: Garret Moddel, Blake J. Eliasson
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Patent number: 6563185Abstract: A detector for detecting electromagnetic radiation incident thereon over a desired range of frequencies exhibits a given responsivity and includes an output and first and second non-insulating layers, which layers are spaced apart such that a given voltage can be applied thereacross. The first non-insulating layer is formed of a metal, and the first and second non-insulating layers are configured to form an antenna structure for receiving electromagnetic radiation over the desired range of frequencies. The detector further includes an arrangement disposed between the first and second non-insulating layers and configured to serve as a transport of electrons between the first and second non-insulating layers as a result of the electromagnetic radiation being received at the antenna structure.Type: GrantFiled: May 21, 2001Date of Patent: May 13, 2003Assignee: The Regents of the University of ColoradoInventors: Garrett Moddel, Blake J. Eliasson
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Patent number: 6542068Abstract: A vertical Hall sensor includes a semiconductor crystal with three or more arm sections that are arranged at a uniform angle distance to each other. A central electrode and external current electrodes are arranged on the surface of the sensor, and a plurality of Hall voltage contacts is arranged therebetween. The semiconductor crystal is thick enough for a current flow to pass between the electrodes in each arm section of the semiconductor crystal, whereby the current flow produces several sensitivities in the Hall sensor corresponding to the number of arm sections with a correspondingly predefined angular dependency for a magnetic field that is directed in a parallel position with respect to the surface. The Hall voltages, which can be produced using one such multi-arm vertical Hall sensor, can be used in a reinforced and direct manner as an output signal for an electric motor.Type: GrantFiled: December 14, 2000Date of Patent: April 1, 2003Assignee: Myonic AGInventors: Axel Drapp, André Bietry, Frédéric Burger, Radivoje Popovic
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Patent number: 6512369Abstract: A magnetoresistor voltage divider includes a bottom layer disposed on a substrate. A middle layer is disposed on the bottom layer. A top layer is disposed on the middle layer. The bottom and top layer are resistive layers and the middle layer is an insulating layer. A common terminal is connected to the bottom layer and the top layer. A reference resistor terminal is connected to the bottom layer only. Moreover, a sensing MR terminal is connected to the top layer only. Accordingly, a sensing MR is established between the common terminal and the sensing MR terminal and a reference resistor is established between the common terminal and the reference resistor terminal. Thus, the sensing MR is stacked on top of the reference resistor.Type: GrantFiled: May 22, 2001Date of Patent: January 28, 2003Assignee: Delphi Technologies, Inc.Inventors: Joseph Pierre Heremans, Dale Lee Partin, Thaddeus Schroeder
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Patent number: 6509620Abstract: A microelectromechanical system (MEMS) device is disclosed for determining the position of a mover. The MEMS device has a bottom layer connected to a mover layer. The mover layer is connected to a mover by flexures. The mover moves relative to the mover layer and the bottom layer. The flexures urge the mover back to an initial position of mechanical equilibrium. The flexures include coupling blocks to control movement of the mover. The MEMS device determines the location of the mover by determining the capacitance between mover electrodes located on the coupling blocks of the flexures and counter electrodes located on an adjacent layer. The coupling block moves according to a determinable relationship with the mover. As the coupling block moves, the capacitance between the mover electrode and the counter electrode changes. A capacitance detector analyzes the capacitance between the electrodes and determines the position of the mover.Type: GrantFiled: May 31, 2001Date of Patent: January 21, 2003Assignee: Hewlett-Packard CompanyInventors: Peter G. Hartwell, Donald J. Fasen
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Patent number: 6504197Abstract: A magnetic memory element has a first ferromagnetic layer, a second ferromagnetic layer, and a non-magnetic layer disposed between these ferromagnetic layers. The non-magnetic layer has an electrical characteristic that is changeable depending on an external magnetic field applied to the non-magnetic layer.Type: GrantFiled: March 16, 2001Date of Patent: January 7, 2003Assignee: Sharp Kabushiki KaishaInventors: Ryoji Minakata, Masashi Michijima, Hidekazu Hayashi
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Patent number: 6501143Abstract: A spin-valve transistor has an emitter, a base including a spin-valve film in which two magnetic layers are stacked with interposing a nonmagnetic layer between the two magnetic layers, and a collector, the spin-valve film having a stacked structure of M/A/M′ or M/B/M′ and the spin-valve film being (100)-oriented, where each of M and M′ includes at least one element selected from the group consisting of Fe, Co, Ni and an alloy including Fe, Co, Ni, A includes at least one element selected from the group consisting of Au, Ag, Pt, Cu and Al, and B includes at least one element selected from the group consisting of Cr and Mn.Type: GrantFiled: June 29, 2001Date of Patent: December 31, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Rie Sato, Koichi Mizushima
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Patent number: 6445024Abstract: The fabrication of ferromagnet-insulator-ferromagnet magnetic tunneling junction devices using a ramp-edge geometry based on, e.g., (La0.7Sr0.3) MnO3, ferromagnetic electrodes and a SrTiO3 insulator is disclosed. The maximum junction magnetoresistance (JMR) as large as 23% was observed below 300 Oe at low temperatures (T<100 K). These ramp-edge junctions exhibited JMR of 6% at 200 K with a field less than 100 Oe.Type: GrantFiled: January 25, 2000Date of Patent: September 3, 2002Assignee: The United States of America, as represented by the Department of EnergyInventors: Chuhee Kwon, Quanxi Jia
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Publication number: 20020113284Abstract: An integrated circuit having at least one micromechanical element thereon is described comprising a support substrate, a sensor element electrically connected to a logic circuit, and the logic circuit electrically connected to a semiconductor visual display element.Type: ApplicationFiled: July 1, 1999Publication date: August 22, 2002Inventor: MICHAEL R. FLANNERY
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Patent number: 6429499Abstract: Disclosed is a semiconductor structure and manufacturing process for making an integrated FET and photodetector optical receiver on a semiconductor substrate. A FET is formed by forming at least one p region in a p-well of the substrate and forming at least one n region in the p-well of the substrate. A p-i-n photodetector is formed in the substrate by forming at least one p region in an absorption region of the substrate when forming the at least one p region in the p well of the FET and forming at least one n region in the absorption region of the substrate when forming the at least one n region in the p-well of the FET.Type: GrantFiled: May 18, 2000Date of Patent: August 6, 2002Assignee: International Business Machines CorporationInventors: Randolph B. Heineke, William K. Hogan, Scott Allen Olson, Clint Lee Schow
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Patent number: 6429498Abstract: The invention relates to a sensor for measuring a magnetic field. The inventive sensor has a high level of measuring sensitivity compared to a Hall probe, comprising several electrically semiconductive layers. The layers are arranged in the form of a power diode connected in the reverse direction, consisting of an anodelayer, a cathode layer and an intrinsically conductive layer enclosed between the two. The anode layer is subdivided by insulation sections into several anode layer areas, these areas being insulated from each other. The cathode layer has an injector area on the areas opposite the insulation sections which is oppositely doped. An electron beam is formed between the injector area and the anode by applying an injection voltage to the injector area. The electron beam is distributed across the areas of the earthed anode layer areas in the form of uniform partial currents.Type: GrantFiled: February 28, 2001Date of Patent: August 6, 2002Assignee: Forschungszentrum Jülich GmbHInventors: Jakob Schelten, Ralf Lehmann
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Patent number: 6426539Abstract: Bolometric detector with intermediate electrical insulation and manufacturing process for this detector. According to the invention, at least two electrodes are formed facing the same face of a layer of bolometric material (5) and starting from the same layer of conducting material (8). Areas (8A, 8B) belonging to the two electrodes are electrically isolated from each other and electrically isolated from the layer of bolometric material, while other areas (7A, 7B) belonging to the two electrodes are separated from each other and are in electrical contact with this layer. The invention is particularly applicable to infrared imagery.Type: GrantFiled: June 28, 2000Date of Patent: July 30, 2002Assignee: Commissariat a l'Energie AtomiqueInventors: Michel Vilain, Jean-Jacques Yon
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Patent number: 6396114Abstract: A hall device portion 15 is formed in the right side of a silicon substrate 11. A first magnetic film 23 is formed on the surface of an etched groove 19 formed in the reverse side of the silicon substrate 11. A second magnetic film 27 is formed on the surface of an etched groove 19a formed in the silicon substrate 11a. A polyimide layer 25 is used to bond the silicon substrate 11a having the second magnetic film 27 to the right side of the silicon substrate 11. Therefore, the two magnetic films sandwich the hall device portion 15. Therefore, external magnetic fields are efficiently converged to the hall device portion 15 by the first magnetic film 23 and the second magnetic film 27.Type: GrantFiled: June 1, 2000Date of Patent: May 28, 2002Assignee: Yazaki CorporationInventor: Haruo Yoshinaga
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Patent number: 6307241Abstract: Submicron ferromagnets, of selected size and spacing, are introduced into semiconductor by means of ion implantation and subsequent heat treatments. The resulting semiconductor contains ferromagnets at high density and which exhibit Curie temperatures exceeding room temperature. The semiconductor retains its intrinsic physical properties, such as optical and transport properties, after incorporation of the ferromagnetic nanostructures.Type: GrantFiled: June 7, 1995Date of Patent: October 23, 2001Assignee: The Regents of the Unversity of CaliforniaInventors: David D. Awschalom, Pierre M. Petroff, Jing Shi, James M. Kikkawa
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Publication number: 20010031547Abstract: A semiconductor device for generating spin-polarized conduction electrons including a ferromagnetic semiconductor layer and a non-magnetic semiconductor layer having a band alignment of Type II with respect to the ferromagnetic semiconductor, said ferromagnetic semiconductor layer and non-magnetic semiconductor layer being connected together directly or with interposing therebetween another non-magnetic semiconductor layer or energy barrier layer such that a spin splitting of a conduction band of the non-magnetic semiconductor layer is induced by a spontaneous spin splitting of a valence band of the ferromagnetic semiconductor layer, and spin-polarized conduction electrons are generated in the non-magnetic semiconductor layer by the spin splitting of the conduction band of the non-magnetic semiconductor layer.Type: ApplicationFiled: March 7, 2001Publication date: October 18, 2001Applicant: TOHOKU UNIVERSITYInventors: Hideo Ohno, Fumihiro Matsukura
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Patent number: 6281538Abstract: An improved and novel multi-layer thin film device including a graded-stoichiometry insulating layer (16) and a method of fabricating a multi-layer thin film device including a graded-stoichiometry insulating layer (16). The device structure includes a substrate (12), a first electrode (14), a second electrode (18), and a graded-stoichiometry insulating, or tunnel-barrier, layer (16) formed between the first electrode (14) and the second electrode (18). The graded-stoichiometry insulating tunnel-barrier layer (16) includes graded stoichiometry to compensate for thickness profile and thereby produce a uniform tunnel-barrier resistance across the structure (10).Type: GrantFiled: March 22, 2000Date of Patent: August 28, 2001Assignee: Motorola, Inc.Inventor: Jon Slaughter
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Patent number: 6140139Abstract: A Hall effect ferromagnetic non-volatile random access memory cell comprising a Hall effect sensor adjacent to a ferromagnetic bit which is surrounded by a drive coil. The coil is electrically connected to a drive circuit, and when provided with an appropriate current creates a residual magnetic field in the ferromagnetic bit, the polarity of which determines the memory status of the cell. The Hall effect sensor is electrically connected via four conductors to a voltage source, ground, and two read sense comparator lines for comparing the voltage output to determine the memory status of the cell. The read and write circuits are arranged in a matrix of bit columns and byte rows. A method for manufacturing said Hall effect ferromagnetic non-volatile random access memory cell.Type: GrantFiled: December 22, 1998Date of Patent: October 31, 2000Assignees: Pageant Technologies, Inc., Estancia Limited ProvidencialsInventors: Richard Lienau, Laurence Sadwick
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Patent number: 6114719Abstract: A magnetic tunnel junction (MTJ) memory cell uses a biasing ferromagnetic layer in the MTJ stack of layers that is magnetostatically coupled with the free ferromagnetic layer in the MTJ stack to provide transverse and/or longitudinal bias fields to the free ferromagnetic layer. The MTJ is formed on an electrical lead on a substrate and is made up of a stack of layers.Type: GrantFiled: May 29, 1998Date of Patent: September 5, 2000Assignee: International Business Machines CorporationInventors: Frederick Hayes Dill, Robert Edward Fontana, Jr., Tsann Linn, Stuart Stephen Papworth Parkin, Ching Hwa Tsang
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Patent number: 5939764Abstract: The DC transformer includes structure having a high mobility, two-dimensional electron gas contained within a plane therein. A magnetic field is maintained normal to the electron gas plane and the transformer structure is kept at a cryogenic temperature. Gate electrodes on the structure are biased negatively with respect to the electron gas and shaped to create a quantum point contact connecting two quantized Hall regions in the electron gas. The two regions have different quantized Hall conductivites. In one embodiment, this difference is due to different donor concentrations. Because the current is the same in the two regions, an input voltage applied across the one region will be stepped up or stepped down as measured between the output contacts to the other region.Type: GrantFiled: April 23, 1997Date of Patent: August 17, 1999Assignee: President and Fellows of Harvard CollegeInventors: Dmitri Chklovskii, Bertrand I. Halperin
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Patent number: 5831513Abstract: A magnetic field sensing device for simultaneously measuring all components of a magnetic field is disclosed. The present invention includes a conductive stack formed in a semiconductor substrate, where the conductive stack includes some ion-implanted layers abutting to each other, and each of the ion-implanted layers has a different and decreasing dosage level down to the bottom layer. The present invention also includes a first conductive contact on a first end of the top layer surface of the ion-implanted layers, and a second conductive contact on a second end of the top layer surface of the ion-implanted layers. A current flows into the first conductive contact and leave the second conductive contact, so that a horizontal magnetic field that exerts on the magnetic field sensing device is measured.Type: GrantFiled: February 4, 1997Date of Patent: November 3, 1998Assignee: United Microelectronics Corp.Inventor: Lormen Jaw-Chyng Lue
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Patent number: 5808349Abstract: A strong magnetic field is applied to a photoconductive semiconductor switch to make the opening time of the switch independent of the recombination time of the photoionized semiconductor. As a result, the switch is capable of shaping current pulses with the fidelity of an illuminating optical pulse used to activate the switch. The strong magnetic field applied to the photoconductive semiconductor switch has a strength satisfying the relationship .mu.B>1, where .mu. is the mobility of the semiconductor (in m.sup.2 /Volt Sec) and B the magnetic field (in Tesla). Such a switch acts as an insulator (magnetic insulation) to an applied electric field except during the time that the light incident thereon generates electron-hole pairs. During that time, a polarization current, proportional to the externally induced pair production rate, flows and the magnetic insulation is broken. The minimal system response time is controlled by the gyrofrequency of the carriers.Type: GrantFiled: December 5, 1995Date of Patent: September 15, 1998Assignee: APTI Inc.Inventor: Konstantinos Papadopoulos
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Patent number: 5543988Abstract: A magnetic sensor, memory, and magnetic imager has been described for sensing a magnetic field in two directions concurrently incorporating a bar of semiconductor material having a rectangular cross-section, electrodes for introducing current along the length of the semiconductor material, and electrodes positioned on respective corners of the rectangular cross-section at a common distance along the current path whereby the Hall voltage may be detected concurrently in two directions. The memory includes the above magnetic sensor plus a disk having a magnetic layer thereon for storing information, a positioner for moving the disk, a memory control circuit and a signal processor circuit. The magnetic imager includes a plurality of magnetic field sensors positioned in a one or two-dimensional array. The invention overcomes the problem of mapping magnetic fields with high spatial resolution with high magnetic sensitivity in two directions concurrently.Type: GrantFiled: June 7, 1995Date of Patent: August 6, 1996Assignee: International Business Machines CorporationInventors: Michael J. Brady, Lia Krusin-Elbaum, William T. Masselink, Padmanabhan Santhanam, Tsuyoshi Tamegai
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Patent number: 5502325Abstract: A magnetoresistor is monolithically integrated with an active circuit by growing a thin film magnetoresistor on a semiconductor substrate after the substrate has been doped and annealed for the active devices. The magnetoresistor is grown through a window in a mask, with the mask and magnetoresistor materials selected such that the magnetoresistor is substantially non-adherent to the mask. InSb is preferred for the magnetoresistor, Si.sub.3 N.sub.4 for the mask and GaAs for the substrate. The non-adherence allows the mask to be substantially thinner than the magnetoresistor without impairing the removal of the mask after the magnetoresistor has been established.Type: GrantFiled: May 30, 1995Date of Patent: March 26, 1996Assignee: Hughes Aircraft CompanyInventors: Marko Sokolich, Hiroyuki Yamasaki, Huai-Tung Yang
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Patent number: 5442221Abstract: A Hall effect sensor of two-dimensional electron gas type comprising, on an insulating substrate, a quantum well structure, a carrier injection layer adjacent to the quantum well structure, of thickness less than 250 .ANG. and having an density per unit area of donors integrated over the whole thickness of the carrier injection layer less than 5.times.10.sup.12 cm.sup.-2, an insulating burial layer deposited on the carrier injection layer, having a conduction band with an energy level greater than the Fermi energy of the sensor and a thickness greater than 200 .ANG.. Applicable to the field of electricity meters and current sensors.Type: GrantFiled: May 24, 1993Date of Patent: August 15, 1995Assignee: Schlumberger Industries, S.A.Inventors: Vincent Mosser, Jean-Louis Robert
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Patent number: 5416353Abstract: A magnetoresistance effect element is prepared by successively forming one upon the other a first magnetic layer, a P- or N-type semiconductor layer, a second magnetic layer, and a magnetization fixing layer in this order on an insulating substrate. A Schottky junction is formed between the first magnetic layer and the semiconductor layer and between the semiconductor layer and the second magnetic layer. The relative angle between the magnetization direction within the first magnetic layer and the magnetization direction within the second magnetic layer is changed depending on the intensity of the magnetic field, leading to a change in the tunnel conductance.Type: GrantFiled: September 10, 1993Date of Patent: May 16, 1995Assignee: Kabushiki Kaisha ToshibaInventors: Yuzo Kamiguchi, Atsuhito Sawabe, Masashi Sahashi, Hitoshi Iwasaki
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Patent number: 5371388Abstract: An electron wave interference device includes a source electrode for injecting electrons therethrough, a drain electrode for taking out electrons therethrough, channel means for propagating electrons from the source electrode to the drain electrode and a gate electrode provided on a halfway portion of the channel means between the source electrode and the drain electrode for dividing the channel means into plural channels solely in the halfway portion of the channel means. A positional relationship between the channel means and the gate electrode is set so that a depletion layer is extended under the gate electrode toward the channel means by applying a given voltage to the gate electrode. The depletion layer extended through the channel means forms an island which inhibits the propagation of electrons in the channel means and thus divides the channel means into the plural channels.Type: GrantFiled: March 10, 1994Date of Patent: December 6, 1994Assignee: Canon Kabushiki KaishaInventor: Hitoshi Oda
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Patent number: 5332911Abstract: A semiconductor radiation detector with layer-wise construction and a contive region having a two-dimensional or quasi one-dimensional electron or hole gas is provided in which adiabatic transport in edge channels occurs at least regionally and in which at least two contacts are provided to this conductive region. The transport in the edge channels is disturbed by interaction with the electromagnetic radiation to be detected, i.e. an increase of the scattering rate between the edge channels is caused. This leads to a change of the resistance measurable between the contacts, with a means being provided for measuring the change of resistance to thereby detect the incident radiation.Type: GrantFiled: January 17, 1992Date of Patent: July 26, 1994Assignee: Max-Planck-Gesellschaft zur Foerderung der Wissenschaften, e.V.Inventors: Klaus von Klitzing, Gerhard Mueller, Edgar Diessel, Dieter Weiss
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Patent number: 5324977Abstract: A hybrid integrated circuit device has a magnetic sensor formed directly on a substrate by photolithography. Alternatively, a flip chip type magnetic sensor is mounted on a substrate by fusion. The magnetic sensor can be mounted on the substrate with high positional precision.Type: GrantFiled: November 18, 1992Date of Patent: June 28, 1994Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Ziro Honda, Masato Imanaka
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Patent number: 5323050Abstract: A collector arrangement for a magnetotransistor (10, 25, 30) and a method for making the magnetotransistor (10, 25, 30). A portion of a semiconductor substrate (11) is doped to form a base region (13). The base region is doped to form an emitter region (16, 26, 36) and a collector region (17, 27, 37) such that the collector region (17, 27, 37) surrounds and is spaced apart from the emitter region (16, 26, 36). Collector contacts (C.sub.1 -C.sub.8 and C.sub.5 '-C.sub.8 ', C.sub.13 -C.sub.16) are symmetrically formed in the collector region (17, 27, 37). In a three-dimensional magnetotransistor (10, 25) the collector contacts include split-collector contacts (C.sub.5 -C.sub.8 and C.sub.5 '-C.sub.8 ').Type: GrantFiled: June 1, 1993Date of Patent: June 21, 1994Assignee: Motorola, Inc.Inventor: Ljubisa Ristic
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Patent number: 5229621Abstract: A magnetic semiconductor element formed by joining a magnetostrictive material and a semiconductive material with each other, in which the lattice constant of the semiconductive material is variable by magnetostriction at the interface therebetween; or in which an interface between the two materials is formed by epitaxial growth and the orientation of the magnetostriction is identical to the orientation in which the lattice constant of the semiconductive material varies. Next, a semiconductor laser is so constructed that the interface between the magnetostrictive material and the semiconductive material is disposed in the semiconductor laser and the wavelength and the output of the semiconductor laser are variable by magnetostriction. Further, a method of making a magnetic semiconductor element comprises a step of epitaxially growing the layer of the magnetostrictive material on the layer made of the semiconductive material.Type: GrantFiled: May 26, 1992Date of Patent: July 20, 1993Assignee: Hitachi, Ltd.Inventors: Matahiro Komuro, Yuzo Kozono, Masanobu Hanazono