Resistive Patents (Class 365/100)
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Patent number: 6646902Abstract: A non-volatile memory device, such as a Programmable Conductor Random Access Memory (PCRAM) device, having an exemplary memory stored state retention characteristic is disclosed. There is provided a method for retaining stored states in a random access memory device generally comprising the steps of programming a memory cell or an array of memory cells by applying a first voltage to the cells and stabilizing the cells by applying a second voltage to the cells, which is less than the first voltage. The second voltage, which acts as a stabilizing voltage, may be a read-out voltage. The second voltage may also be continuously applied to the cells. The second voltage may also be provided as a sweep voltage, a pulse voltage, or a step voltage.Type: GrantFiled: August 30, 2001Date of Patent: November 11, 2003Assignee: Micron Technology, Inc.Inventors: Terry L. Gilton, Kristy A. Campbell
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Publication number: 20030206428Abstract: A driver circuit having one or more MOS transistors. The driver circuit is capable of providing an output voltage greater than the power supply voltage; however, the magnitude of the voltages appearing across the terminals of the MOS transistors are preferably less than or equal to the magnitude of the power supply voltage. The driver circuit may comprise a plurality of serially coupled PMOS transistors and a plurality of serially coupled NMOS transistors wherein the plurality of PMOS transistors and plurality of NMOS transistors are coupled at the output node of the driver.Type: ApplicationFiled: May 1, 2002Publication date: November 6, 2003Inventor: Ward Parkinson
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Patent number: 6643161Abstract: Storing a data bit includes exposing a volume of a polymer, having a first conductivity, to an electron beam. Exposing damages cross-links in the volume of material. A first conductivity of the polymer is changed to a second conductivity and the data is stored in the bit.Type: GrantFiled: October 28, 2002Date of Patent: November 4, 2003Assignee: Intel CorporationInventors: Eric C. Hannah, Michael A. Brown
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Publication number: 20030185036Abstract: A method for reading and verifying the state of a memory cell during a write operation before writing allows a decision to be made whether to write to the cell or not based on the current state of the cell.Type: ApplicationFiled: March 28, 2002Publication date: October 2, 2003Applicant: Micron Technology, Inc.Inventors: Terry L. Gilton, John T. Moore
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Patent number: 6625055Abstract: A read-only memory device is described having non-volatile memory cells that include a memory component connected between electrically conductive traces. A memory component is formed to include a resistor that indicates a resistance value when a potential is applied to a selected memory cell. The resistance value of a memory component in an individual memory cell corresponds to multiple logical bits. The resistance value of a memory component corresponding to a set of logical bits can be based on a thickness and/or an area of electrically resistive material that forms the memory component, and/or based on the geometric shape of the memory component, where different geometric shapes of the electrically resistive material have different resistance values that correspond to different sets of logical bits.Type: GrantFiled: April 9, 2002Date of Patent: September 23, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: Kenneth K. Smith, Sarah M. Brandenberger, Darrel R. Bloomquist, Kenneth J. Eldredge, Andrew L. Van Brocklin, Peter J. Fricke
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Publication number: 20030174530Abstract: A data storage device having parallel memory planes is disclosed. Each memory plane includes a first resistive cross point plane of memory cells, a second resistive cross point plane of memory cells, a plurality of conductive word lines shared between the first and second planes of memory cells, a plurality of bit lines, each bit line coupling one or more cells from the first plane to another memory cell in the second plane, and a plurality of unidirectional elements. Further, the one unidirectional element couples a first memory cell from the first plane to a selected word line and a selected bit line in a first conductive direction and a second unidirectional element couples a second cell from the second plane to the selected word line and selected bit line in a second conductive direction. The device further provides for a unidirectional conductive path to form from a memory cell in the first plane to a memory cell in the second plane sharing the same bit line.Type: ApplicationFiled: March 14, 2002Publication date: September 18, 2003Inventor: Lung T. Tran
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Publication number: 20030156467Abstract: A removable memory card and an associated read/write device and its method of operation are disclosed. The memory card may be formed of a sheet of chalcogenide glass material which has memory storage locations therein defined by the locations of conductive read/write elements of the read/write device.Type: ApplicationFiled: February 20, 2002Publication date: August 21, 2003Inventors: Terry L. Gilton, Trung T. Doan
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Patent number: 6608773Abstract: A memory system, comprising: a memory cell comprising a programmable resistance element programmable to at least a first resistance state and a second resistance state. The memory cell interconnecting a row line and a column line. A power line, distinct from the row line and the column line, coupling said memory cell to a power source.Type: GrantFiled: October 10, 2001Date of Patent: August 19, 2003Assignee: Ovonyx, Inc.Inventors: Tyler Lowrey, Guy C. Wicker
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Patent number: 6597598Abstract: A data storage device that includes a resistive cross point array of memory cells, a plurality of word lines, and a plurality of bit lines, and a sense amplifier that utilizes an injection charge amplifier is disclosed. The memory cells are arranged into multiple groups of one or more memory cells. The injection charge amplifier determines whether a sensed memory cell is in a first or second resistive state as compared to a reference cell.Type: GrantFiled: April 30, 2002Date of Patent: July 22, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: Lung T. Tran, Frederick A. Perner
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Patent number: 6597009Abstract: A method including, in a dielectric material over a contact on a substrate, forming a trench to the contact; introducing an electrode material along the sidewalls of the trench; introducing a phase change material over material along a first sidewall; and modifying the electrode material along the sidewalls such that only the material along the first sidewall acts as a conductive path between the contact and the phase change material. An apparatus including a chalcogenide memory element; a contact; and a heater element comprising two leg portions, a first leg portion coupled to the contact and the chalcogenide memory element, and only the first leg portion acts as a conductive path between the contact and the chalcogenide memory element.Type: GrantFiled: January 4, 2002Date of Patent: July 22, 2003Assignee: Intel CorporationInventor: Guy C. Wicker
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Patent number: 6597600Abstract: An offset compensated memory element voltage supply including a differential amplifier with a compensation circuit, and a transistor with a gate connected to the output of the differential amplifier. The compensation circuit of the differential amplifier includes a compensation capacitor that stores a compensation voltage during a calibration phase, and applies the stored compensation voltage to a compensation input of the compensation circuit of the amplifier during a measurement phase. Feedback from a source of the transistor controls the output of the differential amplifier to maintain a standard voltage across a resistive memory element connected to the source during measurement of the resistance of the resistive memory element, and the compensation circuit improves the accuracy of the voltage across the resistive memory element by compensating for an offset voltage of the differential amplifier.Type: GrantFiled: August 27, 2001Date of Patent: July 22, 2003Assignee: Micron Technology, Inc.Inventor: R. J. Baker
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Patent number: 6590807Abstract: A cell in a structural phase-change memory is programmed by raising cell voltage and cell current to programming threshold levels, and then lowering these to quiescent levels below their programming levels. A precharge pulse is then applied which raises the bitline voltage of the selected cell and does not raise the cell voltage and cell current to their programming levels. Then, the cell current is raised to a read level which is below the programming threshold level, and the bitline voltage is compared to a reference voltage while the cell current is at the read level.Type: GrantFiled: August 2, 2001Date of Patent: July 8, 2003Assignee: Intel CorporationInventor: Tyler A. Lowrey
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Publication number: 20030123274Abstract: In an embodiment, the present invention is directed to a system for intermediating communication, with a moveable media library, utilizing partitions, wherein the moveable media library comprises an internal controller that is, in part, operable to control a robotics subsystem in response to commands received via a control interface. Such a system comprises: a bridge unit that is operable to pass library commands to an external controller, wherein the bridge unit is operable to associate a plurality of logic units (LUNs) with the external controller. The external controller is operable to process library commands from the bridge unit, wherein the external controller associates each partition of a plurality of partitions with a respective LUN of the plurality of LUNs, and the external controller is further operable to translate received commands from the bridge unit for communication to the internal controller according to the plurality of partitions.Type: ApplicationFiled: December 28, 2001Publication date: July 3, 2003Inventors: Peter Thomas Camble, Stephen Gold, Daryl Stolte
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Patent number: 6570782Abstract: Methods for storing a bit sequence are provided. A representative method for storing a bit sequence includes converting a first bit sequence containing a first number of low-resistance bits into a second bit sequence containing a second number of low-resistance bits that is lower than the first number of low-resistance bits, and then storing the second bit sequence in a resistance-based memory device. Systems, computer-readable media, and other methods for storing and retrieving a bit sequence are also provided.Type: GrantFiled: January 16, 2002Date of Patent: May 27, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: Sarah M. Brandenberger, Peter J. Fricke, Kenneth K. Smith
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Patent number: 6570795Abstract: A memory device includes memory components that represent a logic value corresponding to a data bit in a bit sequence. A defective memory component in the memory device represents a data bit in the bit sequence. An additional memory component in the memory device represents an encode bit in the bit sequence, where the encode bit indicates whether the bit sequence is inverted.Type: GrantFiled: April 10, 2002Date of Patent: May 27, 2003Assignee: Hewlett-Packard Development Company, L.P.Inventors: Peter Fricke, Andrew L. Van Brocklin, Daryl Anderson
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Patent number: 6567293Abstract: An apparatus including a volume of phase change material disposed between a first conductor and a second conductor on a substrate, and a plurality of electrodes coupled to the volume of phase change material and the first conductor. A method including introducing, over a first conductor on a substrate, a plurality of electrodes coupled to the first conductor, introducing a phase change material over the plurality of electrodes and in electrical communication with the plurality of electrodes, and introducing a second conductor over the phase change material and coupled to the phase change material.Type: GrantFiled: September 29, 2000Date of Patent: May 20, 2003Assignee: Ovonyx, Inc.Inventors: Tyler A. Lowrey, Manzur Gill
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Publication number: 20030090922Abstract: An apparatus including a volume of phase change material disposed between a first conductor and a second conductor on a substrate, and a plurality of electrodes coupled to the volume of phase change material and the first conductor. A method including introducing, over a first conductor on a substrate, a plurality of electrodes coupled to the first conductor, introducing a phase change material over the plurality of electrodes and in electrical communication with the plurality of electrodes, and introducing a second conductor over the phase change material and coupled to the phase change material.Type: ApplicationFiled: October 25, 2002Publication date: May 15, 2003Inventors: Tyler A. Lowrey, Manzur Gill
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Publication number: 20030081445Abstract: An integrated circuit includes an array of state-change devices, first and second decoder circuits for selecting a particular state-change device. A voltage source is coupled to the first decoder circuit and sense circuitry is coupled to the second decoder to receive an electrical parameter from the selected state-change device and to detect a particular value of the electrical parameter. A control circuit is coupled to the voltage source, the first and second decoders, and the sense circuitry to select a first voltage from the voltage source to alter the selected state-change device and to select a second voltage from the voltage source when the sense circuitry detects the particular value of the electrical parameter.Type: ApplicationFiled: October 31, 2001Publication date: May 1, 2003Inventors: Andrew L. Van Brocklin, Peter Fricke, S. Jonathan Wang
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Patent number: 6542397Abstract: An apparatus including at least one designated memory cell of a plurality of memory cells. Disposed within each designated memory cell is a resistance-altering constituent. Consequently, a first binary value is recognoized in each designated cell and at least a second binary value is recognized in each remaining cell.Type: GrantFiled: June 25, 2001Date of Patent: April 1, 2003Assignee: Lucent Technologies Inc.Inventor: Allen Paine Mills, Jr.
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Publication number: 20030058678Abstract: In the ferroelectric memory device an auxiliary polysilicon layer is formed on an interlayer insulating layer having a polysilicon contact plug formed therein. A metal silicide layer is formed on the auxiliary polysilicon layer. A capacitor structure is then formed on the metal silicide layer.Type: ApplicationFiled: July 15, 2002Publication date: March 27, 2003Inventors: Hyoung-Joon Kim, Yong-Tak Lee
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Publication number: 20030035313Abstract: The method of forming a ferroelectric memory device includes forming capacitor patterns over a substrate, each capacitor pattern having an adhesive assistant pattern, a lower electrode, a ferroelectric pattern, and an upper electrode. An oxygen barrier layer is formed over the substrate and is etched to expose a sidewall of the ferroelectric pattern but not a sidewall of the adhesive assistant pattern. Then, a thermal process for curing ferroelectricity of the ferroelectric pattern in performed.Type: ApplicationFiled: April 30, 2002Publication date: February 20, 2003Inventors: Kyu-Mann Lee, Yong-Tak Lee, Hyeong-Geun An
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Publication number: 20030031040Abstract: A semiconductor storage device with high soft-error immunity is obtained. A semiconductor storage device has SRAM memory cells. NMOS transistors (Q1, Q4) are driver transistors, NMOS transistors (Q3, Q6) are access transistors, and PMOS transistors (Q2, Q5) are load transistors. An NMOS transistor (Q7) is a transistor for adding a resistance. The NMOS transistor (Q7) has its gate connected to a power supply (1). The NMOS transistor (Q7) has one of its source and drain connected to a storage node (ND1) and the other connected to the gates of the NMOS transistor (Q4) and the PMOS transistor (Q5). The resistance between the source and drain of the NMOS transistor (Q7) can be adjusted with the gate length, the gate width, the source/drain impurity concentration, etc., which is, for example, about several tens of kilohms (k&OHgr;).Type: ApplicationFiled: July 25, 2002Publication date: February 13, 2003Applicant: MITSUBISHI DENKI KABUSHIKI KAISHAInventors: Yuuichi Hirano, Takashi Ipposhi
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Publication number: 20020196653Abstract: A ferroelectric memory device includes a microelectronic substrate and a plurality of ferroelectric capacitors on the substrate, arranged as a plurality of rows and columns in respective row and column directions. A plurality of parallel plate lines overlie the ferroelectric capacitors and extend along the row direction, wherein a plate line contacts ferroelectric capacitors in at least two adjacent rows. The plurality of plate lines may include a plurality of local plate lines, and the ferroelectric memory device may further include an insulating layer disposed on the local plate lines and a plurality of main plate lines disposed on the insulating layer and contacting the local plate lines through openings in the insulating layer. In some embodiments, ferroelectric capacitors in adjacent rows share a common upper electrode, and respective ones of the local plate lines are disposed on respective ones of the common upper electrodes.Type: ApplicationFiled: May 2, 2002Publication date: December 26, 2002Inventors: Hyun-Ho Kim, Dong-JIn Jung, Ki-Nam Kim, Sang-Don Nam, Kyu-Mann Lee
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Publication number: 20020196652Abstract: An apparatus including at least one designated memory cell of a plurality of memory cells. Disposed within each designated memory cell is a resistance-altering constituent. Consequently, a first binary value is recognized in each designated cell and at least a second binary value is recognized in each remaining cell.Type: ApplicationFiled: June 25, 2001Publication date: December 26, 2002Inventor: Allen Paine Mills
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Publication number: 20020196651Abstract: An 8F2 (2×2F wordline pitch by 2F bitline pitch) memory cell uses a vertical gate transistor having one gate driving two sources and two drains, one source and drain being formed on each side of the trench. Because two channels are provided, the device allows for sufficient current capacity, even with a 2F gate length. The memory cell array is formed in a series of active regions, corresponding to the bit lines of the array, which active regions are bounded by isolation trenches between the bit lines. The deep trenches segment the active regions and the overlying bit lines tie the cells of a given row together. Each memory cell has two drain regions, each having two contacts to the bit line and adjacent cells share one drain region, resulting in four contacts to the bit line for each memory cell.Type: ApplicationFiled: June 22, 2001Publication date: December 26, 2002Inventor: Rolf Weis
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Publication number: 20020172068Abstract: Bit lines and source lines are precharged to a power supply voltage before data read operation. In the data read operation, a corresponding bit line is coupled to a data bus as well as a corresponding source line is driven to a ground voltage only in the selected memory cell column. In the non-selected memory cell columns, the bit lines and the source lines are retained at the precharge voltage, i.e., the power supply voltage. No charging/discharging current is produced in the bit lines of the non-selected memory cell columns, that is, a charging/discharging current that does not directly contribute the data read operation is not produced, thereby allowing for reduction in power consumption in the data read operation.Type: ApplicationFiled: October 22, 2001Publication date: November 21, 2002Applicant: Mitsubishi Denki Kabushiki KaishaInventor: Hideto Hidaka
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Patent number: 6483734Abstract: A memory device includes memory cells having a re-writeable element and a write-once element in series with the re-writeable element. The re-writeable element is programmable between a high resistance state and a low resistance state. The write-once element can be an anti-fuse element that is programmable from a high resistance state to a low resistance state, or a fuse element that is programmable from a low resistance state to a high resistance state. The two possible states for the re-writeable element and the two possible states for the write-once element allow the memory cells to store four different bits.Type: GrantFiled: November 26, 2001Date of Patent: November 19, 2002Assignee: Hewlett Packard CompanyInventors: Manish Sharma, Lung T. Tran
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Patent number: 6480438Abstract: To provide equal cell programming conditions, the integrated circuit device has a number of bitline compensation elements each coupled in series with a separate bitline, and a number of wordline compensation elements each coupled in series with a separate wordline. The resistances in these compensation elements are such that a variation in a sum of (1) the resistance along the corresponding bitline of a cell between the first terminal of the cell and a far terminal of the bitline compensation element that is coupled to the corresponding bitline and (2) the resistance along the corresponding wordline of the cell between a second terminal of the cell and a far terminal of the wordline compensation element that is coupled to the corresponding wordline, is minimized across the cells of the array.Type: GrantFiled: June 12, 2001Date of Patent: November 12, 2002Assignee: Ovonyx, Inc.Inventor: Eungjoon Park
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Publication number: 20020159286Abstract: A magnetic random access memory (MRAM) circuit block and access method thereof are disclosed herein which includes a circuit for sensing a data write current passing through a bitline 32 and, for generating a stop signal for stopping a data write current supply to the bitline 32 and a write wordline 30 after data is written in an magnetic tunnel junction (MTJ) element 44. Further, when data to be written to the storage element is the same as the data already stored therein, no write current is supplied to the write wordline 30, thereby saving power.Type: ApplicationFiled: April 26, 2002Publication date: October 31, 2002Applicant: International Business Machines CorporationInventors: Toshio Sunaga, Hisatada Miyatake, Koji Kitamura, Hideo Asano, Kohki Noda, Hiroshi Umezaki
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Publication number: 20020154531Abstract: A memory system, comprising: a memory cell comprising a programmable resistance element programmable to at least a first resistance state and a second resistance state. The memory cell interconnecting a row line and a column line. A power line, distinct from the row line and the column line, coupling said memory cell to a power source.Type: ApplicationFiled: October 10, 2001Publication date: October 24, 2002Inventors: Tyler Lowrey, Guy C. Wicker
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Patent number: 6456525Abstract: A data storage device includes a resistive cross point array of memory cells. Each memory cell includes a memory element and a resistive element connected in series with the memory element. The resistive elements substantially attenuate any sneak path currents flowing through shorted memory elements during read operations. The data storage device may be a Magnetic Random Access Memory (“MRAM”) device.Type: GrantFiled: September 15, 2000Date of Patent: September 24, 2002Assignee: Hewlett-Packard CompanyInventors: Frederick A. Perner, Thomas C. Anthony
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Publication number: 20020114179Abstract: A contactless channel write/erase flash memory cell structure and its fabricating method for increasing the level of integration is disclosed. The present invention utilizes a buried diffusion method to form an N+-doped region that acts as a drain of the flash memory cell and a P-doped region underneath an oxide layer. The N+-doped region and the P-doped region extend to in a bit line direction and a metal contact is used to connect the two away from any of the N+-doped region and the P-doped region of the flash memory cell for decreasing the numbers of the metal contacts in the flash memory cell and reducing dimensions of the device.Type: ApplicationFiled: January 22, 2002Publication date: August 22, 2002Inventors: Ching-Hsiang Hsu, Ching-Sung Yang
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Patent number: 6424557Abstract: An integrated device comprises at least one circuit element and a plurality of trimming elements which can be connected selectively to the at least one circuit element in order to achieve a predetermined tolerance of a characteristic parameter of the at least one circuit element; the integrated device includes a plurality of electronic switches, each of which can be switched between a first state and a second state in which it activates and deactivates a corresponding one of the trimming elements, respectively, and a memory for storing an indication of the states of the electronic switches and for operating each electronic switch in the first state or in the second state according to the indication stored.Type: GrantFiled: November 30, 2000Date of Patent: July 23, 2002Assignee: STMicroelectronics S.r.l.Inventors: Alessandro Camera, Paolo Sandri, Ignazio Bellomo, Filippo Marino
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Patent number: 6404665Abstract: An apparatus comprising a volume of memory material and a pair of spacedly disposed conductors. An electrode coupled to the volume of memory material and disposed between the volume of memory material and one conductor comprises a first material having a first resistivity value and a second material having a different second resistivity value formed by exposing the first material to a gaseous ambient.Type: GrantFiled: September 29, 2000Date of Patent: June 11, 2002Assignee: Intel CorporationInventors: Tyler A. Lowrey, Daniel Xu, Chien Chiang, Patrick J. Neschleba
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Publication number: 20020039306Abstract: An apparatus including a volume of phase change material disposed between a first conductor and a second conductor on a substrate, and a plurality of electrodes coupled to the volume of phase change material and the first conductor. A method including introducing, over a first conductor on a substrate, a plurality of electrodes coupled to the first conductor, introducing a phase change material over the plurality of electrodes and in electrical communication with the plurality of electrodes, and introducing a second conductor over the phase change material and coupled to the phase change material.Type: ApplicationFiled: January 30, 2001Publication date: April 4, 2002Inventor: Tyler A. Lowrey
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Patent number: 6314014Abstract: A memory system comprising memory cells and reference cells each including a programmable resistance element. The resistance state of a memory cell is determined by comparing a sense signal developed by the memory cell with a reference signal developed by one or more of the reference cells. The programmable resistance elements may comprise a phase-change material.Type: GrantFiled: December 16, 1999Date of Patent: November 6, 2001Assignee: Ovonyx, Inc.Inventors: Tyler Lowrey, Guy C. Wicker
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Patent number: 6236587Abstract: A read-only memory is made electrically addressable over a passive conductor matrix, wherein at least a portion of the volume between intersection of two conductors (2;4) in the matrix defines a memory cell (5) in the read-only memory. Data are stored as impedance values in the memory cells. The memory cells (5) comprise either an isolating material (6) which provides high impedance or one or more inorganic or organic semiconductors (9), preferably with an anisotropic conducting property. The semiconductor material (9) forms a diode junction at the interface to a metallic conductor (2;4) in the matrix. By suitable arrangement of respectively the isolating material (6) and semiconductor material (9) in the memory cells these may be given a determined impedance value which may be read electrically and corresponds to logical values in a binary or multi-valued code.Type: GrantFiled: September 13, 1999Date of Patent: May 22, 2001Inventors: Hans Gude Gudesen, Per-Erik Nordal, Geirr I. Leistad
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Patent number: 6188615Abstract: Resistance of a selected memory cell in a Magnetic Random Access Memory (“MRAM”) device is sensed by a read circuit including a direct injection charge amplifier, an integrator capacitor and a digital sense amplifier. The direct injection charge amplifier supplies current to the integrator capacitor while maintaining an equipotential voltage on non-selected memory cells in the MRAM device. As the direct injection charge amplifier applies a fixed voltage to the selected memory cell, the sense amplifier measures integration time of a signal on the integrator. The signal integration time indicates whether the memory cell MRAM resistance is at a first state (R) or a second state (R+&Dgr;R).Type: GrantFiled: October 29, 1999Date of Patent: February 13, 2001Assignee: Hewlett-Packard CompanyInventors: Frederick A. Perner, Kenneth J. Eldredge, Lung T. Tran
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Patent number: 6147925Abstract: In a shared sense amplifier structure, a bit line isolating gate connecting a selected memory block and a sense amplifier circuit is set to a high-resistance ON state when a sensing operation is performed, and the high-resistance ON state is held during a row selected state. A semiconductor memory device allowing fast access with a low power consumption is implemented.Type: GrantFiled: June 23, 1999Date of Patent: November 14, 2000Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Shigeki Tomishima, Tsukasa Ooishi
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Patent number: 6011742Abstract: A single pull-up circuit is shared between a redundant row antifuse cell, and a redundant column antifuse cell. Additionally, a single selection circuit is shared between the two antifuse cells. A row selection signal supplied thereto selects the antifuse cell for the redundant row, while a column selection signal selects the antifuse cell for the redundant column. A small channel length transistor is employed within the latch circuit. As a result, the latch can quickly pull up a value when the antifuse cell is not blown, and quickly latch that value within the latch since an RC time constant of the latch is decreased. A pulsed pull-up signal having a very short duration is employed to enable the latch. Since the pulsed pull-up signal has a short duration, a high voltage supply V.sub.CC is provided through the latch and a blown antifuse cell to ground for only a short duration, thereby minimizing the possibility of such a low resistance current path from damaging the circuitry.Type: GrantFiled: August 20, 1997Date of Patent: January 4, 2000Assignee: Micron Technology, Inc.Inventor: Hua Zheng
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Patent number: 5982659Abstract: A process which enables storage of more than two logic states in a memory cell. In one embodiment, a via is used to couple a diode between a word read line and a data read line. The via has a resistance which is set to one of a plurality of values at the time of manufacture. When the word read line is asserted, the voltage drop sustained across the via is indicative of the stored logic state. An analog-to-digital (A/D) converter is coupled to the data read line so as to sense the voltage drop and determine the state represented. Since the additional logic states may be used to represent additional information bits, this memory circuit increases the number of bits that may be stored per memory cell, thereby increasing the storage density and reducing the cost per bit.Type: GrantFiled: December 23, 1996Date of Patent: November 9, 1999Assignee: LSI Logic CorporationInventors: V. Swamy Irrinki, Thomas R. Wik, Raymond T. Leung, Ashok Kapoor, Alex Owens
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Patent number: 5978298Abstract: A single pull-up circuit is shared between a redundant row antifuse cell, and a redundant column antifuse cell. Additionally, a single selection circuit is shared between the two antifuse cells. A row selection signal supplied thereto selects the antifuse cell for the redundant row, while a column selection signal selects the antifuse cell for the redundant column. A small channel length transistor is employed within the latch circuit. As a result, the latch can quickly pull up a value when the antifuse cell is not blown, and quickly latch that value within the latch since an RC time constant of the latch is decreased. A pulsed pull-up signal having a very short duration is employed to enable the latch. Since the pulsed pull-up signal has a short duration, a high voltage supply V.sub.CC is provided through the latch and a blown antifuse cell to ground for only a short duration, thereby minimizing the possibility of such a low resistance current path from damaging the circuitry.Type: GrantFiled: September 17, 1998Date of Patent: November 2, 1999Assignee: Micron Technology, Inc.Inventor: Hua Zheng
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Patent number: 5978249Abstract: A circuit (200) comprises transistors (240, 250, 260), an operational amplifier (270) and serially coupled resistors (210, 220). The circuit (200) is coupled to reference lines (201, 202). An input voltage V.sub.X on an input terminal (203) is applied across the resistors (210, 220) and divided to an output voltage V.sub.Y on an output terminal (204). Output voltage V.sub.Y is measured (as V.sub.M) by the operational amplifier (270). The operational amplifier (270) controls a current I.sub.A in a first current path between the reference lines (201, 202). The current I.sub.A is mirrored to a current I.sub.S in a second current path through the resistors (210, 220). The current I.sub.S is generated by one of the transistors (260) and substantially proportional to the input voltage V.sub.X. Therefore, the resistors (210, 220) do not substantially load the input and the circuit (200) exhibits a high input impedance.Type: GrantFiled: December 17, 1997Date of Patent: November 2, 1999Assignee: Motorola Inc.Inventors: Vladimir Koifman, Yachin Afek
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Patent number: 5978258Abstract: A variable resistance material-based memory cell is disclosed for use in an electronic memory. The memory cell includes a MOS diode for delivering large amounts of current to the variable resistance material, as needed during programming of the memory cell. In one embodiment, a buried contact under the gate is used as the drain of the device. The buried contact allows formation of a very short channel, causing a "snapback" phenomenon in the MOS diode and thereby greatly increasing the amount of current flow across the device. This buried contact construction has the additional advantage of reducing the area needed for the memory cell. Additionally, the processing is simple and may be performed using the same techniques normally used during the fabrication of electronic memories.Type: GrantFiled: June 19, 1998Date of Patent: November 2, 1999Assignee: Micron Technology, Inc.Inventor: Monte Manning
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Patent number: 5978248Abstract: An integrated circuit anti-fuse is described which is fabricated as a capacitor using a layer of oxide. The two plates of the anti-fuse are coupled to appropriate voltage levels to rupture the oxide and form a conductive short between the plates. One of the plates is formed as a diffused well which is coupled to an external voltage during programming. The well is biased to an internal voltage during normal operation of the circuit incorporating the anti-fuse.Type: GrantFiled: February 25, 1998Date of Patent: November 2, 1999Assignee: Micron Technology, Inc.Inventors: Kenneth W. Marr, Shubneesh Batra
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Patent number: 5969978Abstract: A memory architecture for a regular array of non-volatile ferromagnetic rom access annular memory elements which can be based on the giant magnetoresistance (GMR) effect. A first sense row in the array connects the memory elements with strips which are staggered so that each memory element is connected through its upper surface to the memory element on one side and through the lower surface to one on the other side. Running transverse to the first sense row is a word line made up of a series of wires passing in magnetic field producing proximity to the memory elements along a column of the array and not being in electrical contact with the memory elements. The strips of the word line are staggered so they similarly produce a meandering conductive pathway through the word line from one side of the array to the other in series. The wires of the word line can pass through the open core of the annular element or the wires can pass adjacent to the memory elements.Type: GrantFiled: September 30, 1998Date of Patent: October 19, 1999Assignee: The United States of America as represented by the Secretary of the NavyInventor: Gary A. Prinz
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Patent number: 5963472Abstract: A mask ROM is so configured as to read out information through the utilization of a cumulative time delay involved when a read-out signal applied to memory elements making connection between a word line WL1 and bit lines BL1 crossing the word line is passed through delay elements R1 to R7, that is, as to read out stored information on a time base, in which the conductions of switching transistors T1 to T8 are controlled by the outputs of the delay elements R1 to R7 and the information appearing at the bit line BL1 is sequentially read out at a predetermined time corresponding to a time delay resulting from the delay elements R1 to R7.Type: GrantFiled: July 22, 1998Date of Patent: October 5, 1999Assignee: NKK CorporationInventors: Nobufumi Inada, Koji Shigematsu, Junichi Kitabuki, Tetsuya Hayashi
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Patent number: 5949708Abstract: A charge pump coupling circuit is described for more efficiently coupling a final capacitive stage of a charge pump to a capacitive load. The coupling circuit is has primarily resistive characteristics to allow for a greater load voltage. The resistive coupling circuit in one embodiment is included in a memory device for coupling a charge pump to a memory array word line. The resistive coupling circuit can be either a single resistor, a plurality of resistors, or a coupling circuit which has substantially resistive characteristics.Type: GrantFiled: December 31, 1997Date of Patent: September 7, 1999Assignee: Micron Technology, Inc.Inventor: Christopher J. Chevallier
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Patent number: 5936880Abstract: A static, in-circuit programmable memory device is provided where the storage element employed is a bi-layer programmable resistor. A specialized programming and readout circuit is provided for each storage element, allowing a known word-line/bit-line memory architecture (commonly used with fuse type memories) to be adapted to a memory element that conducts in both of two different states. The programming and readout circuit may take the form of a merged bipolar/FET device. A bipolar transistor is used for programming and also provides a diode action to prevent sneak path currents from flowing when a storage element is not selected. The bipolar transistor may be a parasitic bipolar transistor. An FET is used for readout. Storage elements are paired, one storage element of each pair functioning as a reference element.Type: GrantFiled: November 13, 1997Date of Patent: August 10, 1999Assignee: VLSI Technology, Inc.Inventor: Robert L. Payne
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Patent number: 5926417Abstract: A read method for reading data from a ROM device is provided, which can be operated with a higher voltage to address the memory cells in the ROM device. The ROM device are formed with word and bit lines formed from metallization layers having a very low resistance so that the data current can be increased for increased performance. This read method is for use on a ROM device of the type including an array of memory cells formed at the intersections between a plurality of word lines and a plurality of bit lines. Of these memory cells, a first selected group are set to a permanently-ON state due to the forming of a contact window connecting the associated word line to the associated bit line, and a second selected group of the memory cells are set to a permanently-OFF state due to the forming of no contact window therein.Type: GrantFiled: November 6, 1997Date of Patent: July 20, 1999Assignee: United Microelectronics Corp.Inventor: Kuang-Yeh Chang