Abstract: A method of erasing and programming a flash memory device including multi-level cells (MLCs). MLCs of a word line are selected and some of the MLCs are pre-programmed based on whether their individual threshold voltages are included in a first voltage range. The selected MLCs are pre-programmed with a pre-program (first) voltage; and the remaining MLCs are prohibited from pre-programming; then the remaining MLCs connected to the selected word line are programmed by applying a program (second) voltage that gradually rises from the pre-program voltage at a ratio of a step voltage n for the selected line.

Abstract: Erase and program methods of a flash memory device including MLCs for increasing the program speed. In the erase method, MLCs are pre-programmed so that a voltage range in which threshold voltages of MLCs are distributed can be reduced. Therefore, a fail occurrence ratio can be reduced when erasing MLCs, the threshold voltage distribution of MLCs can be improved and an overall program time can be shortened in a subsequent program operation.

Abstract: A non-volatile memory device includes a first cell group including memory cells other than memory cells adjacent to a drain select transistor in a block, and a second cell group including the memory cells adjacent to the drain select transistor in the block. An erase operation is performed on the memory cells in the block. The first cell group is programmed by applying a first soft programming voltage to the first cell group. The second cell group is programmed by applying a second soft programming voltage to the second cell group.

Abstract: A method of reading a NAND flash memory device includes a cell string having a drain selection transistor, a plurality of memory cells and a source selection transistor which are in series connected to each other. The method comprises the steps of applying a first voltage to a gate of the drain selection transistor in order to turn on the drain selection transistor, applying a read voltage to a gate of a selected memory cell among the plurality of memory cells, and applying first and second pass voltages to gates of unselected memory cells of the plurality of memory cells, wherein the first pass voltage of a relatively high level is applied to the gates of the unselected memory cells which are adjacent to the selected memory cell and wherein the second pass voltage of a relatively high level is applied to the gates of the unselected memory cells which are not adjacent to the selected memory.

Abstract: Provided is a method of reading a flash memory device for depressing read disturb. According to the method, a first voltage is applied to a gate of the drain select transistor to turn on the drain select transistor, and a read voltage is applied to a gate of a selected transistor among the plurality of memory cells. Then, a pass voltage is applied to gates of unselected transistors among the plurality of memory cells. Furthermore, when the pass voltage is applied, a first pass voltage is applied and then a second pass voltage is applied after an elapse of a predetermined time following the applying of the first pass voltage. The second pass voltage has a level different from that of the first pass voltage.

Abstract: Erase and program methods of a flash memory device including MLCs for increasing the program speed are described. In the erase method, MLCs are pre-programmed so that a voltage range in which threshold voltages of MLCs are distributed can be reduced. Therefore, a fail occurrence ratio can be reduced when erasing MLCs, the threshold voltage distribution of MLCs can be improved and an overall program time can be shortened in a subsequent program operation.

Abstract: Erase and program methods of a flash memory device including MLCs for increasing the program speed are described. In the erase method, MLCs are pre-programmed so that a voltage range in which threshold voltages of MLCs are distributed can be reduced. Therefore, a fail occurrence ratio can be reduced when erasing MLCs, the threshold voltage distribution of MLCs can be improved and an overall program time can be shortened in a subsequent program operation.

Abstract: Erase and program methods of a flash memory device including MLCs for increasing the program speed are described. In the erase method, MLCs are pre-programmed so that a voltage range in which threshold voltages of MLCs are distributed can be reduced. Therefore, a fail occurrence ratio can be reduced when erasing MLCs, the threshold voltage distribution of MLCs can be improved and an overall program time can be shortened in a subsequent program operation.

Abstract: A non-volatile memory device includes a first cell group including memory cells other than memory cells adjacent to a drain select transistor in a block, and a second cell group including the memory cells adjacent to the drain select transistor in the block. An erase operation is performed on the memory cells in the block. The first cell group is programmed by applying a first soft programming voltage to the first cell group. The second cell group is programmed by applying a second soft programming voltage to the second cell group.

Abstract: A method of reading a NAND flash memory device includes a cell string having a drain selection transistor, a plurality of memory cells and a source selection transistor which are in series connected to each other. The method comprises the steps of applying a first voltage to a gate of the drain selection transistor in order to turn on the drain selection transistor, applying a read voltage to a gate of a selected memory cell among the plurality of memory cells, and applying first and second pass voltages to gates of unselected memory cells of the plurality of memory cells, wherein the first pass voltage of a relatively high level is applied to the gates of the unselected memory cells which are adjacent to the selected memory cell and wherein the second pass voltage of a relatively high level is applied to the gates of the unselected memory cells which are not adjacent to the selected memory.

Abstract: Provided is a method of reading a flash memory device for depressing read disturb. According to the method, a first voltage is applied to a gate of the drain select transistor to turn on the drain select transistor, and a read voltage is applied to a gate of a selected transistor among the plurality of memory cells. Then, a pass voltage is applied to gates of unselected transistors among the plurality of memory cells. Furthermore, when the pass voltage is applied, a first pass voltage is applied and then a second pass voltage is applied after an elapse of a predetermined time following the applying of the first pass voltage. The second pass voltage has a level different from that of the first pass voltage.

Abstract: FeRAM and a method for generating a reference voltage are disclosed. The ferroelectric memory device includes: a memory cell unit having a plural memory cells equipping a ferroelectric capacitor and a first current gain transistor; a reference cell unit having a reference cell quipping a ferroelectric capacitor and a second current gain transistor; and a sense amp unit for comparing voltages, amplifying the voltage difference and outputting data, wherein a size of the two ferroelectric capacitor in the memory cell and the reference cell is identical and a size of the first current gain transistor and the second current gain transistor is different. As mentioned above, the present invention can generate a reference voltage by implementing different size of current gain transistors. Therefore, it can reduce time and cost to optimize a size of a ferroelectric capacitor for manufacturing high integrated 1T1C ReRAM.

Abstract: FeRAM and a method for generating a reference voltage are disclosed. The ferroelectric memory device includes: a memory cell unit having a plural memory cells equipping a ferroelectric capacitor and a first current gain transistor; a reference cell unit having a reference cell quipping a ferroelectric capacitor and a second current gain transistor; and a sense amp unit for comparing voltages, amplifying the voltage difference and outputting data, wherein a size of the two ferroelectric capacitor in the memory cell and the reference cell is identical and a size of the first current gain transistor and the second current gain transistor is different. As mentioned above, the present invention can generate a reference voltage by implementing different size of current gain transistors. Therefore, it can reduce time and cost to optimize a size of a ferroelectric capacitor for manufacturing high integrated 1T1C ReRAM.