Patent application number | Description | Published |
20090046496 | NONVOLATILE MEMORY DEVICE - A variable resistance element ( | 02-19-2009 |
20100046270 | RESISTANCE VARIABLE MEMORY APPARATUS - A resistance variable memory apparatus ( | 02-25-2010 |
20100110766 | NONVOLATILE MEMORY APPARATUS AND METHOD FOR WRITING DATA IN NONVOLATILE MEMORY APPARATUS - A nonvolatile memory apparatus comprises a memory array ( | 05-06-2010 |
20100110767 | RESISTANCE VARIABLE MEMORY APPARATUS - A resistance variable memory apparatus ( | 05-06-2010 |
20100202185 | NONVOLATILE MEMORY DEVICE AND METHOD OF WRITING DATA TO NONVOLATILE MEMORY DEVICE - A nonvolatile memory device ( | 08-12-2010 |
20110128776 | NONVOLATILE MEMORY DEVICE AND METHOD OF WRITING DATA TO NONVOLATILE MEMORY DEVICE - A resistance variable layer has a characteristic in which the resistance variable layer changes to a second resistance state (RL) in such a manner that its resistance value stops decreasing when an interelectrode voltage reaches a first voltage (V | 06-02-2011 |
20110182109 | VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE AND PROGRAMMING METHOD FOR SAME - A variable resistance nonvolatile memory device ( | 07-28-2011 |
20120069633 | NONVOLATILE STORAGE DEVICE AND METHOD FOR WRITING INTO THE SAME - The nonvolatile storage device includes a variable resistance element ( | 03-22-2012 |
20120280713 | NONVOLATILE LATCH CIRCUIT AND NONVOLATILE FLIP-FLOP CIRCUIT - A nonvolatile latch circuit of the invention includes a variable resistance element which is formed by interposing an oxide layer between electrodes, and changes to a low resistance state by applying a voltage to cause current flow in the direction from the first to the second electrode, and changes to a high resistance state by applying a voltage to cause current flow in the reverse direction, wherein a first terminal of a transistor, a first terminal of other transistor, an output terminal of an inverter circuit, and an output terminal of other inverter circuit are respectively connected to one electrode, the other electrode, a second terminal of the transistor, and a second terminal of the other transistor, and a current flowing through the variable resistance element when changed to a low resistance state is smaller in absolute value than a current therethrough when changed to a high resistance state. | 11-08-2012 |
20130021838 | METHOD OF INSPECTING VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE AND VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE - A method of inspecting a variable resistance nonvolatile memory device detecting a faulty memory cell of a memory cell array employing a current steering element, and a variable resistance nonvolatile memory device are provided. The method of inspecting a variable resistance nonvolatile memory device having a memory cell array, a memory cell selection circuit, and a read circuit includes: determining that a current steering element has a short-circuit fault when a variable resistance element is in a low resistance state and a current higher than or equal to a predetermined current passes through the current steering element, when the resistance state of the memory cell is read using a second voltage; and determining whether the variable resistance element is in the low or high resistance state, when the resistance state of the memory cell is read using a first voltage. | 01-24-2013 |
20130077384 | CROSS POINT VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE AND METHOD OF READING THEREBY - A cross point variable resistance nonvolatile memory device including: a cross point memory cell array having memory cells each of which is placed at a different one of cross points of bit lines and word lines; a word line decoder circuit that selects at least one of the memory cells from the memory cell array; a read circuit that reads data from the selected memory cell; an unselected word line current source that supplies a first constant current; and a control circuit that controls the reading of the data from the selected memory cell, wherein the control circuit controls the word line decoder circuit, the read circuit, and the unselected word line current source so that when the read circuit reads data, the first constant current is supplied to an unselected word line. | 03-28-2013 |
20130107606 | NONVOLATILE LATCH CIRCUIT, NONVOLATILE FLIP-FLOP CIRCUIT, AND NONVOLATILE SIGNAL PROCESSING DEVICE | 05-02-2013 |
20130148408 | METHOD OF PROGRAMMING VARIABLE RESISTANCE NONVOLATILE MEMORY ELEMENT - A method of programming a variable resistance nonvolatile memory element that removes a defect in a resistance change, ensures an operation widow, and stably sustains a resistance change operation, the method including: applying, when the detect in the resistance change occurs in the variable resistance nonvolatile memory element, a recovery voltage pulse at least once to the variable resistance nonvolatile memory element, the recovery voltage pulse including: a first recovery voltage pulse that has an amplitude greater than amplitudes of a normal high resistance writing voltage pulse and a low resistance writing voltage pulse; and a second recovery voltage pulse that is the low resistance writing voltage pulse following the first recovery voltage pulse. | 06-13-2013 |
20130188414 | VARIABLE RESISTANCE NONVOLATILE MEMORY ELEMENT WRITING METHOD AND VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE - A variable resistance nonvolatile memory element writing method of, by applying a voltage pulse to a memory cell including a variable resistance element, reversibly changing the variable resistance element between a first resistance state and a second resistance state according to a polarity of the applied voltage pulse is provided. The variable resistance nonvolatile memory element writing method includes applying a first preliminary voltage pulse and subsequently applying the first voltage pulse to the variable resistance element to change the variable resistance element from the second resistance state to the first resistance state, the first preliminary voltage pulse being smaller in voltage absolute value than the second threshold voltage and different in polarity from the first voltage pulse. | 07-25-2013 |
20130208531 | NONVOLATILE MEMORY DEVICE AND METHOD OF WRITING DATA TO NONVOLATILE MEMORY DEVICE - A resistance variable layer changes: to a second resistance state in such a manner that its resistance value stops decreasing when an interelectrode voltage reaches a negative first voltage; to a first resistance state in such a manner that its resistance value starts increasing when the interelectrode voltage reaches a positive second voltage which is equal in absolute value to the first voltage; to the first resistance state in such a manner that the resistance variable layer flows an interelectrode current such that the interelectrode voltage is maintained at a third voltage higher than the second voltage, when the interelectrode voltage reaches the third voltage; and to the first resistance state in such a manner that its resistance value stops increasing when the interelectrode current reaches a first current in a state where the interelectrode voltage is not lower than the second voltage and lower than the third voltage. | 08-15-2013 |
20130223133 | CROSS POINT VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE AND METHOD OF WRITING THEREBY - A cross point variable nonvolatile memory device includes a memory cell array including: first memory cells (e.g., part of a memory cell array) having a common word line; and second memory cells (e.g., another part of the memory cell array or a compensation cell unit). When a predetermined memory cell among the first memory cells is written to by changing the predetermined memory cell to a first resistance state, a word line write circuit supplies a first voltage or a first current to a selected word line, a first bit line write circuit supplies a third voltage or a third current to one bit line of the first memory cells, and a second bit line write circuit supplies the third voltage or the third current to A bit line or lines of the second memory cells. | 08-29-2013 |
20140050015 | NONVOLATILE STORAGE DEVICE AND METHOD FOR WRITING INTO THE SAME - The nonvolatile storage device includes a variable resistance element and a write circuit which writes data into the variable resistance element, wherein the variable resistance element has a property of changing from a first resistance state to a second resistance state when a pulse of a first voltage is applied to the variable resistance element, and changing from the second resistance state to the first resistance state when a pulse of a second voltage is applied to the variable resistance element, and the write circuit applies, to the variable resistance element, at least the pulse of the first voltage, a pulse of a third voltage, and the pulse of the first voltage in this order, when the variable resistance element is caused to change from the first resistance state to the second resistance state. | 02-20-2014 |
20140078809 | NONVOLATILE LATCH CIRCUIT, NONVOLATILE FLIP-FLOP CIRCUIT, AND NONVOLATILE SIGNAL PROCESSING DEVICE - A nonvolatile latch circuit according to the present invention includes: a latch operating unit in which outputs of cross-coupled connected inverter circuit and inverter circuit are connected via a series circuit which includes a transistor, a variable resistance element, and a transistor in this order, and store and restore in a latch state are controlled by control terminals of the transistors; and a comparator circuit which compares a signal obtained by amplifying the value of the sum of potentials at both ends of the variable resistance element with the logic state of the latch operating unit, wherein writing to and reading from the variable resistance element are repeated until an output of the comparator circuit indicates that normal write operation has been performed. | 03-20-2014 |
20140078811 | VARIABLE RESISTANCE NONVOLATILE MEMORY ELEMENT WRITING METHOD AND VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE - Provided is a method of writing to a variable resistance nonvolatile memory element which is capable of both improving retention characteristics and enlarging a window of operation. In the method of writing, to write “1” data (LR), first a weak HR writing process is performed in which a weak HR writing voltage pulse set for changing the variable resistance nonvolatile memory element to an intermediate resistance state is applied and, subsequently, a LR writing process is performed in which a LR writing voltage pulse set for changing the variable resistance nonvolatile memory element from the intermediate resistance state to a LR state is applied. | 03-20-2014 |
20140078814 | CROSSPOINT NONVOLATILE MEMORY DEVICE AND METHOD OF DRIVING THE SAME - The nonvolatile memory device includes a control circuit that controls a sense amplification circuit and a writing circuit. The control circuit changes a value of at least one of (a) a load current and (b) a forming pulse current or a forming pulse voltage, according to a total number of sneak current paths formed by memory cells each including a variable resistance element in a second resistance state having a low resistance value except a selected memory cell in a memory cell array. | 03-20-2014 |
20140104931 | NONVOLATILE MEMORY DEVICE AND METHOD OF PERFORMING FORMING THE SAME - A nonvolatile memory device including a control unit configured to read resistance value information for each of memory cells as initial resistance value information and store it temporarily before a voltage pulse for forming is applied, to set resistance value information as a threshold value serving as a target for completion of the forming, the resistance value information being obtained by multiplying the initial resistance value information by a predetermined coefficient, and to repeat application of the voltage pulse for forming and reading of the resistance value information until a resistance value indicated by the resistance value information on the memory cell becomes lower than a resistance value indicated by the threshold value. | 04-17-2014 |
20140185360 | WRITE METHOD FOR WRITING TO VARIABLE RESISTANCE NONVOLATILE MEMORY ELEMENT AND VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE - A write method for writing to a variable resistance nonvolatile memory element, comprising applying a set of strong recovery-voltage pulses at least once to the variable resistance nonvolatile memory element when it is determined that the resistance state of the variable resistance nonvolatile memory element fails to change to a second resistance state, remaining in a first resistance state, the set of strong recovery-voltage pulses including pulses: (1) a first strong recovery-voltage pulse which has a greater amplitude than a normal second voltage for changing the resistance state to the first resistance state, and has the same polarity as the second voltage; and (2) a second strong recovery-voltage pulse which follows the first strong recovery-voltage pulse and has a longer pulse width than the pulse width of the normal first voltage for changing the resistance state to the second resistance state, and has the same polarity as the first voltage. | 07-03-2014 |
20140301129 | WRITING METHOD OF VARIABLE RESISTANCE NON-VOLATILE MEMORY ELEMENT AND VARIABLE RESISTANCE NON-VOLATILE MEMORY DEVICE - A writing method of a variable resistance non-volatile memory element comprises determining, in a first determination step, whether or not a resistance state of the variable resistance non-volatile memory element does not switch to a first resistance state and remains in a second resistance state, when a pulse of a second voltage is applied to the variable resistance non-volatile memory element; and when it is determined that the resistance state of the variable resistance non-volatile memory element does not switch to the first resistance state and remains in the second resistance state in the first determination step, applying, in a recovery step, at least once to the variable-resistance non-volatile memory element a recovery voltage pulse set composed of two pulses which are a first recovery voltage pulse which has the same polarity as that of the first voltage and a second recovery voltage pulse which has the same polarity as that of the second voltage, has a greater amplitude than the second voltage, and is applied subsequently to the first recovery voltage pulse. | 10-09-2014 |
20140321196 | VARIABLE RESISTANCE NONVOLATILE MEMORY DEVICE AND METHOD FOR WRITING INTO THE SAME - In a method for writing into a variable resistance nonvolatile memory device according to one aspect of the present disclosure, a verify write operation of newly applying a voltage pulse for changing a resistance state is performed on a variable resistance element which does not satisfy a determination condition for verifying that the resistance state has been changed despite application of a voltage pulse for changing the resistance state, and the determination condition in the verify write operation is relaxed when an average number of times of verify write operation, having already been performed on all or part of a plurality of variable resistance elements that are targets for write operation, exceeds a predetermined number of times. | 10-30-2014 |