Patent application number | Description | Published |
20080198659 | SEMICONDUCTOR MEMORY DEVICE - A semiconductor memory device includes: a memory cell array having a plurality of memory cells arranged therein; and a sense amplifier circuit configured to read data of the memory cell array, wherein a comparison operation is performed between read out data from the memory cell array and externally supplied expectance data in the sense amplifier circuit. | 08-21-2008 |
20080301532 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device comprises a memory cell array including a plurality of memory cells arrayed capable of storing information of N bits (N≧2) in accordance with variations in threshold voltage. A parity data adder circuit adds parity data for error correction to every certain data bits to be stored in the memory cell array. A frame converter circuit uniformly divides frame data containing the data bits and the parity data into N pieces of subframe data. A programming circuit stores the subframe data divided into N pieces in respective N sub-pages formed corresponding to the information of N bits. | 12-04-2008 |
20090067255 | NONVOLATILE SEMICONDUCTOR MEMORY INCLUDING MEMORY CELL FOR STORING MULTILEVEL DATA HAVING TWO OR MORE VALUES - A write controller performs verification for checking whether each memory cell is on a predetermined verification level. For a memory cell to be written to a voltage level higher than the predetermined verification level, the write controller stores, in first and second latch circuits, the number of times of write to be performed by a write voltage after the verification. Whenever write is performed by the write voltage, the write controller updates the number of times of write stored in the first and second latch circuits. After write is performed the number of times of write by the write voltage, the write controller performs write by an intermediate voltage lower than the write voltage. | 03-12-2009 |
20090073764 | NONVOLATILE SEMICONDUCTOR STORAGE DEVICE CAPABLE OF HIGH-SPEED WRITING - A memory cell array includes a plurality of memory cells in each of which a plurality of bits are stored. A sense amplifier detects data read from a memory cell selected from the memory cell array. At the time of a write verify operation for verifying write data, when a threshold voltage of the memory cell exceeds a predetermined checkpoint, the data control unit converts write data to be written to the memory cell into data of the number of times indicating the remaining number of write voltage application times, inverts only one bit of the data of the number of times each time a write voltage application operation is performed, and changes a definition of the data of the number of times to thereby perform a subtraction operation. | 03-19-2009 |
20090154239 | NONVOLATILE SEMICONDUCTOR STORAGE APPARATUS - A nonvolatile semiconductor storage apparatus comprises a memory cell array having a plurality of memory cells which are connected to word lines and to bit lines and in each of which different information of x (x is an integer equal to or larger than 3) bits is stored in association with 2 | 06-18-2009 |
20090201726 | NON-VOLATILE SEMICONDUCTOR STORAGE SYSTEM - In a memory cell array, memory cells enabled to store plural-bit data are arranged in matrix. The bit-line control circuit is connected to bit-lines to control the bit-lines. A word line control circuit applies a plural-bit data read voltage as a word line voltage to the word line. The plural-bit data read voltage is larger than an upper limit of one of plural threshold voltage distributions and smaller than a lower limit of another threshold voltage distribution. Furthermore, it applies a soft-value read voltage as a word line voltage to the word line. The soft-value read voltage is smaller than an upper limit of a threshold voltage distribution and larger than a lower limit thereof. The likelihood calculation circuit calculates likelihood of the plural-bit data stores in the memory cells based on the soft-value. | 08-13-2009 |
20090244991 | SEMICONDUCTOR MEMORY DEVICE - A semiconductor memory device comprises a first exclusive-OR circuit which compares mth N-bit first data with (m+1)th N-bit second data, a majority circuit which generates flag data to invert the second data if a comparison result of the first exclusive-OR circuit indicates that the number of mismatch bits between the first data and the second data is not less than N/2, and generates flag data to noninvert the second data if the number of mismatch bits between the first data and the second data is less than N/2, a second exclusive-OR circuit which inverts or noninverts the second data based on the flag data, a shift register which stores the flag data generated by the majority circuit, and a pad to serially output both the inverted or noninverted second data and the flag data. | 10-01-2009 |
20100008157 | SEMICONDUCTOR MEMORY DEVICE CAPABLE OF DETECTING WRITE COMPLETION AT HIGH SPEED - A memory cell array has a plurality of memory cells arrayed in row and column directions. A plurality of sense amplifier units includes a plurality of sense amplifiers detecting write completion of each of the memory cells selected for each row. A plurality of detection units is arranged correspondingly to the sense amplifier units, and forms a transfer path for transferring potential in accordance with a detection output signal of each sense amplifier unit. The detection units detect a sense amplifier unit corresponding to a portion where the transfer path breaks off, as a sense amplifier unit including write incompletion bit. | 01-14-2010 |
20100124109 | SEMICONDUCTOR MEMORY DEVICE FOR STORING MULTI LEVEL DATA - A memory cell array is configured so that a plurality of memory cells which are connected to a word line and a bit line store one value out of n values (n is a natural number of 2 or more) in one memory cell and are arranged in a matrix. A control circuit controls electronic potentials of the word line and the bit line in response to input data to write data in the memory cells. When writing data in the first memory cell of the memory cell array, the control circuit varies a writing level on the basis of writing data to write in a second memory cell adjacent to the first memory cell. | 05-20-2010 |
20100142271 | SEMICONDUCTOR MEMORY DEVICE CAPABLE OF PREVENTING A SHIFT OF THRESHOLD VOLTAGE - A memory cell array is connected to a word line and a bit line, and configured so that a plurality of memory cells storing one level of n levels (n is a natural number more than 4) in one memory cell are arrayed in a matrix. A control circuit controls a potential of the word line and the bit line in accordance with input data, and writs data in the memory cell. The control circuit applies a write voltage corresponding to write data to a memory cell. The write voltage differs for each write data. A verify operation is executed for each write data after a write voltage application operation ends with respect to all n levels. | 06-10-2010 |
20100177567 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE WHICH CAN ELECTRICALLY REWRITE DATA AND SYSTEM THEREFOR - A nonvolatile semiconductor memory device includes a memory cell, latch circuits, and an arithmetic operation circuit. The memory cell stores data by a difference in threshold voltage. A read operation is performed twice or more on the memory cell under the same read conditions, and the latch circuits store a plurality of read data. The arithmetic operation circuit takes majority decision of the plurality of data stored in the latch circuits and decides data determined by the majority decision as data stored in the memory cell. | 07-15-2010 |
20110051510 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE WHICH TRANSFERS A PLURALITY OF VOLTAGES TO MEMORY CELLS AND METHOD OF WRITING THE SAME - According to one embodiment, a nonvolatile semiconductor memory device includes a memory cell array, a bit line, and a voltage generator. The memory cell array includes each of a plurality of memory cells. Each of the memory cells includes a charge storage layer and a control gate and is capable of holding two or more levels of data. The bit line is capable of transferring data to the memory cells in a one-to-one correspondence. The voltage generator carries out a verify operation by applying a verify voltage to the memory cells after performing first writing by applying a first voltage and then a second voltage lower than the first voltage to the control gate. | 03-03-2011 |
20110216599 | SEMICONDUCTOR MEMORY DEVICE AND CONTROL METHOD THEREOF - According to one embodiment, a semiconductor memory device includes a memory cell array, a column decoder, and a control circuit configured to control the memory cell array and the column decoder. The control circuit is configured to load program data from outside, to execute a first data program in a first even-numbered bit line, to execute a second data program in a first odd-numbered bit line, to execute a verify read of the programmed bit lines, to determine whether a value of the verify read is programmed up to a predetermined threshold value, and to change, in a case where the value of the verify read fails to be programmed to the predetermined threshold value, an order of the first and second data programs, to execute the second data program in the first odd-numbered bit line, and then to execute the first data program in the first even-numbered bit line. | 09-08-2011 |
20110299334 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - According to one embodiment, a nonvolatile semiconductor memory device includes a memory cell array connected to word lines and bit lines, and formed by arranging a plurality of memory cells in a matrix, each memory cell storing one of n values (n is a natural number of not less than 2), and a control circuit configured to write data in the memory cells by controlling potentials of the word lines and the bit lines in accordance with input data. The control circuit performs a write verify operation a plurality of number of times by changing a voltage level, stores data of the voltage level at which verify pass occurs, and determines a write voltage based on the stored data of the voltage level. | 12-08-2011 |
20120002470 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device according to an embodiment includes a data write portion, the data write portion includes, in a write loop, a first operation mode of sequentially performing a program operation and a first verify operation, and a second operation mode of sequentially performing the program operation, the first verify operation, and a second verify operation, and the data write portion includes, in the first verify operation, precharging a bit-line connected to the first memory cell and a bit-line connected to a second memory cell adjacent to the first memory cell and verifying data of the first memory cell, then in the second verify operation, when the write to the second memory cell is completed, without precharging the bit-line connected to the second memory cell, precharging the bit-line connected to the first memory cell and verifying data of the first memory cell. | 01-05-2012 |
20120020154 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - According to one embodiment, a nonvolatile semiconductor memory device includes memory cells storing data in a nonvolatile manner, word lines connected to the memory cells and including a first word line and a second word line which is n-th (n is an integer of 1 or more) from the first word line, and a control circuit configured to control a voltage of a word line to write data to a memory cell so that data are written in order from the first word line to the second word line. In a write sequence of the first word line, the control circuit applies a writing voltage to the second word line before writing a memory cell connected to the first word line. | 01-26-2012 |
20120079354 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device comprises a memory cell array including a plurality of memory cells arrayed capable of storing information in accordance with variations in threshold voltage. A likelihood calculator has a plurality of likelihood calculation algorithms for deriving a likelihood value about a stored data bit from a threshold value read out of the memory cell. An error correction unit executes error correction through iterative processing using the likelihood value obtained at the likelihood calculator. A likelihood calculator controller changes among the likelihood calculation algorithms in the likelihood calculator based on a certain value of the number of iterations in the iterative processing obtained from the error correction unit. | 03-29-2012 |
20120144273 | NON-VOLATILE SEMICONDUCTOR MEMORY DEVICE - A non-volatile semiconductor memory device comprises a memory cell array including a plurality of memory cells arrayed capable of storing information of N bits (N≧2) in accordance with variations in threshold voltage. A parity data adder circuit adds parity data for error correction to every certain data bits to be stored in the memory cell array. A frame converter circuit uniformly divides frame data containing the data bits and the parity data into N pieces of subframe data. A programming circuit stores the subframe data divided into N pieces in respective N sub-pages formed corresponding to the information of N bits. | 06-07-2012 |
20120182800 | SEMICONDUCTOR MEMORY DEVICE CAPABLE OF PREVENTING A SHIFT OF THRESHOLD VOLTAGE - A memory cell array is connected to a word line and a bit line, and configured so that a plurality of memory cells storing one level of n levels (n is a natural number more than 4) in one memory cell are arrayed in a matrix. A control circuit controls a potential of the word line and the bit line in accordance with input data, and writs data in the memory cell. The control circuit applies a write voltage corresponding to write data to a memory cell. The write voltage differs for each write data. A verify operation is executed for each write data after a write voltage application operation ends with respect to all n levels. | 07-19-2012 |
20130235657 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE - According to one embodiment, a nonvolatile semiconductor memory device includes a memory cell array and a controller. The controller is configured to perform a verify operation using a first verification voltage and a second verification voltage (first verification voltage09-12-2013 | |
20130258773 | NONVOLATILE SEMICONDUCTOR MEMORY DEVICE WHICH TRANSFERS A PLURALITY OF VOLTAGES TO MEMORY CELLS AND METHOD OF WRITING THE SAME - According to one embodiment, a nonvolatile semiconductor memory device includes a memory cell array, a bit line, and a voltage generator. The memory cell array includes each of a plurality of memory cells. Each of the memory cells includes a charge storage layer and a control gate and is capable of holding two or more levels of data. The bit line is capable of transferring data to the memory cells in a one-to-one correspondence. The voltage generator carries out a verify operation by applying a verify voltage to the memory cells after performing first writing by applying a first voltage and then a second voltage lower than the first voltage to the control gate. | 10-03-2013 |