Patent application number | Description | Published |
20080198668 | NONVOLATILE SEMICONDUCTOR MEMORY AND DRIVING METHOD THEREOF - A nonvolatile semiconductor memory according to an aspect of the invention comprises a plurality of serially connected memory cells arranged on a P-well area within a semiconductor substrate, select gate transistors connected to one end and the other of the serially connected memory cells, a P-well control circuit which controls the P-well area, a plurality of word lines connected to the plurality of memory cells, a row control circuit which controls the plurality of word lines, and an operation control circuit which controls the P-well control circuit and the row control circuit, wherein, when writing to a selected one of the plurality of memory cells, the operation control circuit controls the P-well control circuit to apply a precharge potential to the P-well area and thus precharge channel areas of the plurality of memory cells. | 08-21-2008 |
20080304324 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE WHICH REALIZES "1" WRITE OPERATION BY BOOSTING CHANNEL POTENTIAL - A nonvolatile semiconductor memory device includes a memory cell array having a plurality of cell units each including a preset number of memory cells and select gate transistors on drain and source sides. The nonvolatile semiconductor memory device includes a voltage control circuit to prevent occurrence of an erroneous write operation due to excessively high boost voltage of a channel when “1” is written into the memory cell. | 12-11-2008 |
20090149011 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE AND PROCESS OF MANUFACTURING THE SAME - In device isolation trenches, a first device-isolation insulator film is formed to have recesses thereon and a second device-isolation insulator film is formed in the recesses. The uppermost portions at both ends of the first device-isolation insulator film are located higher than the uppermost portions at both ends of the second device-isolation insulator film. | 06-11-2009 |
20090184390 | SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME - A semiconductor device is disclosed, which includes a semiconductor substrate including a device region and an isolation region having an isolation trench, a gate electrode formed on the device region through a gate insulating film, a first isolation insulating film formed in the isolation trench, the first isolation insulating film having a recess, a second isolation insulating film formed on the first isolation insulating film to be filled in the recess, the second isolation insulating film having an upper surface higher than the upper surface of the semiconductor substrate, and an impurity region formed in the semiconductor substrate under the first isolation insulating film, the impurity region having a conductivity type the same as a conductivity type of the semiconductor substrate, an impurity concentration higher than an impurity concentration of the semiconductor substrate, and a width of the impurity region smaller than a width of the isolation trench. | 07-23-2009 |
20090268521 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device includes a non-volatile memory having a plurality of blocks each including a plurality of memory cells, a bit line electrically connected to one end of a current path of the memory cell, a source line electrically connected to the other end of the current path of the memory cell, a word line electrically connected to the gate electrode, a sense amplifier circuit electrically connected to the bit line and configured to read data from the memory cell, a row decoder electrically connected to the word line and configured to apply a read voltage at which the memory cell is set to an ON state to the word line, and a controller configured to measure a cell current flowing through the memory cell in the ON state to judge whether the memory cell has been degraded. | 10-29-2009 |
20100230739 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE AND PROCESS OF MANUFACTURING THE SAME - In device isolation trenches, a first device-isolation insulator film is formed to have recesses thereon and a second device-isolation insulator film is formed in the recesses. The uppermost portions at both ends of the first device-isolation insulator film are located higher than the uppermost portions at both ends of the second device-isolation insulator film. | 09-16-2010 |
20100232230 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - When data is written to a memory cell transistor, a write controller controls in such a manner that a verification operation subsequent to a program operation is carried out while a program voltage is increased stepwise for each program operation. The write controller controls in such a manner that a verification operation subsequent to a program operation by which a threshold voltage of a memory cell transistor to be written has become equal to or higher than a verification level for the first time is carried out twice or more at the same verification level, verification operations of the second and subsequent times are carried out after a second program operation which is carried out with the memory cell transistor set in an unselected state. | 09-16-2010 |
20110007572 | NAND FLASH MEMORY - A NAND flash memory has memory cell transistors which data is written into. If number of times the program operation has been executed is not equal to the prescribed upper limit number of times, then the program voltage is set so as to be raised by a first potential difference and then the program operation and the verify operation are executed again, and | 01-13-2011 |
20110194354 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - When data is written to a memory cell transistor, a write controller controls in such a manner that a verification operation subsequent to a program operation is carried out while a program voltage is increased stepwise for each program operation. The write controller controls in such a manner that a verification operation subsequent to a program operation by which a threshold voltage of a memory cell transistor to be written has become equal to or higher than a verification level for the first time is carried out twice or more at the same verification level, verification operations of the second and subsequent times are carried out after a second program operation which is carried out with the memory cell transistor set in an unselected state. | 08-11-2011 |
20110220982 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE AND PROCESS OF MANUFACTURING THE SAME - In device isolation trenches, a first device-isolation insulator film is formed to have recesses thereon and a second device-isolation insulator film is formed in the recesses. The uppermost portions at both ends of the first device-isolation insulator film are located higher than the uppermost portions at both ends of the second device-isolation insulator film. | 09-15-2011 |
20120002475 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device includes a non-volatile memory having a plurality of blocks each including a plurality of memory cells, a bit line electrically connected to one end of a current path of the memory cell, a source line electrically connected to the other end of the current path of the memory cell, a word line electrically connected to the gate electrode, a sense amplifier circuit electrically connected to the bit line and configured to read data from the memory cell, a row decoder electrically connected to the word line and configured to apply a read voltage at which the memory cell is set to an ON state to the word line, and a controller configured to measure a cell current flowing through the memory cell in the ON state to judge whether the memory cell has been degraded. | 01-05-2012 |
20120206972 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A control circuit executes an erase operation that includes an erase pulse application operation and an erase verify operation. The erase pulse application operation applies an erase pulse voltage to a memory cell to change the memory cell from a write state to an erase state. The erase verify operation applies an erase verify voltage to the memory cell to judge whether the memory cell is in the erase state or not. The control circuit changes conditions of execution of the erase verify operation when the number of times of executions of the erase pulse application operation in one erase operation reaches a first number. | 08-16-2012 |
20120248524 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE AND PROCESS OF MANUFACTURING THE SAME - In device isolation trenches, a first device-isolation insulator film is formed to have recesses thereon and a second device-isolation insulator film is formed in the recesses. The uppermost portions at both ends of the first device-isolation insulator film are located higher than the uppermost portions at both ends of the second device-isolation insulator film. | 10-04-2012 |
20120257453 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value. | 10-11-2012 |
20120269001 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device according to one embodiment of the present invention includes a memory cell array and a control unit. The control unit is configured to control a repeat of an erase operation, an erase verify operation, and a step-up operation. The control unit is configured to perform a soft-programming operation of setting the memory cells from an over-erased state to a first threshold voltage distribution state when, in a series of erase operations, the number of erase voltage applications is more than a first number and less than a second number (the first number10-25-2012 | |
20120281477 | SEMICONDUCTOR MEMORY DEVICE - According to one embodiment, a semiconductor memory device includes a memory cell array includes a plurality of cell units each composed of a plurality of memory cells which are arranged at intersections of a plurality of bit lines and a plurality of word lines and whose current paths are connected in series and select transistors each connected to either end of the series connection, a voltage generator circuit which generates a voltage applied to the memory cell array, and a control circuit which controls the memory cell array and the voltage generator circuit. | 11-08-2012 |
20130003454 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device according to embodiments has a memory cell array and a reading circuit, and, in a reading sequence, the reading circuit executes a prereading operation of supplying a first reading voltage to an adjacent word line and supplying a first reading pass voltage to a selected word line, and after executing the prereading operation, executes a main reading operation of supplying a fixed second reading voltage to the selected word line and supplying a fixed second reading pass voltage to the adjacent word line while sensing a plurality of electrical physical amounts of a target memory cell with different reading conditions. | 01-03-2013 |
20130058171 | SEMICONDUCTOR STORAGE DEVICE - A semiconductor storage device has a plurality of memory cells each having a control gate that are formed on a well. The semiconductor storage device has a control circuit that applies a voltage to the well and the control gates. | 03-07-2013 |
20130077408 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to the embodiment comprises a memory cell array including plural memory cells operative to store data nonvolatilely in accordance with plural different threshold voltages; and a control unit operative to, in data write to the memory cell, execute write loops having a program operation for changing the threshold voltage of the memory cell and a verify operation for detecting the threshold voltage of the memory cell after the program operation, the control unit, in data write for changing one threshold voltage of the plural threshold voltages, executing the verify operation, when the number of write loops to the memory cell becomes more than a certain defined number, using a condition that can pass the verify operation easier than that when the number of write loops is equal to or less than the certain defined number. | 03-28-2013 |
20130135939 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value. | 05-30-2013 |
20130229873 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device according to one embodiment of the present invention includes a memory cell array and a control unit. The control unit is configured to control a repeat of an erase operation, an erase verify operation, and a step-up operation. The control unit is configured to perform a soft-programming operation of setting the memory cells from an over-erased state to a first threshold voltage distribution state when, in a series of erase operations, the number of erase voltage applications is more than a first number and less than a second number (the first number09-05-2013 | |
20140017875 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE AND PROCESS OF MANUFACTURING THE SAME - In device isolation trenches, a first device-isolation insulator film is formed to have recesses thereon and a second device-isolation insulator film is formed in the recesses. The uppermost portions at both ends of the first device-isolation insulator film are located higher than the uppermost portions at both ends of the second device-isolation insulator film. | 01-16-2014 |
20140085988 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device according to one embodiment of the present invention includes: a memory cell array and a control circuit. The control circuit executes a first reading operation and a second reading operation. The first reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between a control gate electrode and source of the selected memory cell to a first value. The second reading operation is an operation of reading a threshold voltage set in the selected memory cell by setting a voltage between the control gate electrode and source of the selected memory cell to a second value lower than the first value. When executing the second reading operation, the control circuit keeps a voltage of the control gate electrode of the selected memory cell to 0 or a positive value. | 03-27-2014 |
20150029793 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - A nonvolatile semiconductor memory device including: a memory cell array including NAND strings; a plurality of word lines; a plurality of bit lines; a source line; and a control circuit configured to execute a write operation. The control circuit is configured to, when charging an unselected memory string prior to the write operation, execute both first and second charging operations, the first charging operation applying to the bit line connected to the unselected memory string a first voltage and rendering conductive a first select transistor to charge the unselected memory string, and the second charging operation applying to the source line connected to the unselected memory string a second voltage and rendering conductive a second select transistor to charge the unselected memory string, the first and second charging operations being executed at different timings. | 01-29-2015 |