Patent application number | Description | Published |
20100208509 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE, AND PRODUCTION METHOD THEREOF - A nonvolatile semiconductor memory device according to the present invention includes a memory cell array layer including a first line; a plurality of second and third lines that are formed below or above the first line and cross each other; and a plurality of memory cells arranged at each intersection of the second and third lines, the memory cell including a variable resistor and a transistor, which are connected to each other in series between the first line and the third line, the variable resistor being electrically rewritable and storing a resistance value as data in a nonvolatile manner, and the transistor being a columnar transistor having the second line arranged at its side face as a gate. | 08-19-2010 |
20100232198 | SEMICONDUCTOR STORAGE DEVICE - A semiconductor storage device includes: a cell array including a plurality of first wirings, a plurality of second wirings intersecting the first wirings, and memory cells positioned at intersecting portions between the first wirings and the second wirings, each of the memory cells having a series circuit of a non-ohmic element and a variable resistance element; a control circuit configured to apply a control voltage, which is necessary for the variable resistance element to transit from a low resistance state to a high resistance state, to the memory cells through the first wirings and the second wirings; and a bias voltage application circuit configured to apply a bias voltage, which suppresses a potential variation caused by the transition of the variable resistance element from the low resistance state to the high resistance state, to one end of the variable resistance element. | 09-16-2010 |
20100232199 | SEMICONDUCTOR STORAGE DEVICE - A semiconductor storage device includes: a memory cell array including memory cells, each of the memory cells having a variable resistance element; and a control circuit configured to apply a control voltage, which is necessary for the variable resistance element to transit a resistance state, to a selected memory cell. When applying the control voltage plural times, the control circuit operates to set a value of the control voltage applied in a first control voltage application operation to be substantially equal to a minimum value of distribution of the voltage values of all the memory cells in the memory cell array required to transit the resistance state of the variable resistance element from a high resistance state to a low resistance state. The control circuit operates to perform a plurality of control voltage application operations by increasing the value of the control voltage by a certain value. | 09-16-2010 |
20100232207 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE AND METHOD OF RESETTING THE SAME - A nonvolatile semiconductor memory device includes: a plurality of memory cell arrays stacked on a semiconductor substrate and including a plurality of first wires, a plurality of second wires and memory cells disposed at intersections of the first wires and the second wires and having a rectifier element and a variable resistive element are connected in series; and a control circuit configured to selectively drive the first wires and the second wires. The control circuit executes a resetting operation to change a state of the variable resistive element from a low resistance state to a high resistance state. At a time of executing the resetting operation, the control circuit increases a pulse voltage to be applied to the variable resistive element to a first voltage, and then decreases the pulse voltage to a second voltage lower than the first voltage and higher than the ground voltage. | 09-16-2010 |
20100232208 | METHOD OF EXECUTING A FORMING OPERATION TO VARIABLE RESISTANCE ELEMENT - A method of executing a forming operation to a variable resistance element to render a resistance value of the variable resistance element capable of transition, the variable resistance element being included in a memory cell connected between a first wiring and a second wiring and changing the resistance value by electrical control, comprises applying a voltage required to execute the forming operation to the variable resistance element between the first and second wirings and changing the first wiring to a floating state. | 09-16-2010 |
20100238706 | NONVOLATILE SEMICONDUCTOR STORAGE DEVICE - A nonvolatile semiconductor storage device includes a memory core that includes plural banks, the bank including plural memory cells and a data write circuit that supplies a bias voltage to the memory cell, the memory core being logically divided into plural pages, the page including a predetermined number of memory cells belonging to a predetermined number of banks; and a control circuit that controls the data write circuit to perform page write in each write unit including a predetermined number of memory cells, pieces of data being written in the page in the page write, the control circuit performing the page write by repeating a step including a program operation and a verify operation, the control circuit performing the program operation and the verify operation in a next step or later only to the write unit in which the data write is not completed in the verify operation. | 09-23-2010 |
20110032746 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to an embodiment includes a memory cell array including: a plurality of first lines; a plurality of second lines intersecting the first lines; and a plurality of memory cells each including a variable resistance element disposed at the intersection of the first and second lines and configured to store an electrically rewritable resistance value as data in a nonvolatile manner, and a control unit configured to detect an amount of a current flowing through the first line when a memory cell is accessed, and adjust the voltage of the first or second line based on the amount of the current. | 02-10-2011 |
20110044090 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to an embodiment includes: a memory cell array including a plurality of first lines and second lines intersecting each other and a plurality of memory cells connected at intersections of the plurality of first lines and second lines; and a first line control circuit and a second line control circuit configured to select the first lines and the second lines respectively to supply a voltage or current necessary for a resetting operation or a setting operation on the memory cells. The first line control circuit supplies unselected ones of the first lines with an unselecting voltage corresponding to the distance between the unselected first lines and the second line control circuit. | 02-24-2011 |
20120155149 | SEMICONDUCTOR STORAGE DEVICE - A semiconductor storage device includes: a cell array including a plurality of first wirings, a plurality of second wirings intersecting the first wirings, and memory cells positioned at intersecting portions between the first wirings and the second wirings, each of the memory cells having a series circuit of a non-ohmic element and a variable resistance element; a control circuit configured to apply a control voltage, which is necessary for the variable resistance element to transit from a low resistance state to a high resistance state, to the memory cells through the first wirings and the second wirings; and a bias voltage application circuit configured to apply a bias voltage, which suppresses a potential variation caused by the transition of the variable resistance element from the low resistance state to the high resistance state, to one end of the variable resistance element. | 06-21-2012 |
20120163066 | SEMICONDUCTOR STORAGE DEVICE - A semiconductor storage device includes: a memory cell array including memory cells, each of the memory cells having a variable resistance element; and a control circuit configured to apply a control voltage, which is necessary for the variable resistance element to transit a resistance state, to a selected memory cell. When applying the control voltage plural times, the control circuit operates to set a value of the control voltage applied in a first control voltage application operation to be substantially equal to a minimum value of distribution of the voltage values of all the memory cells in the memory cell array required to transit the resistance state of the variable resistance element from a high resistance state to a low resistance state. The control circuit operates to perform a plurality of control voltage application operations by increasing the value of the control voltage by a certain value. | 06-28-2012 |
20120230082 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE AND METHOD OF RESETTING THE SAME - A nonvolatile semiconductor memory device includes: a plurality of memory cell arrays stacked on a semiconductor substrate and including a plurality of first wires, a plurality of second wires and memory cells disposed at intersections of the first wires and the second wires and having a rectifier element and a variable resistive element are connected in series; and a control circuit configured to selectively drive the first wires and the second wires. The control circuit executes a resetting operation to change a state of the variable resistive element from a low resistance state to a high resistance state. At a time of executing the resetting operation, the control circuit increases a pulse voltage to be applied to the variable resistive element to a first voltage, and then decreases the pulse voltage to a second voltage lower than the first voltage and higher than the ground voltage. | 09-13-2012 |