Abstract: Phase change memory devices having cell diodes and related methods are provided, where the phase change memory devices include a semiconductor substrate of a first conductivity type and a plurality of parallel word lines disposed on the semiconductor substrate, the word lines have a second conductivity type different from the first conductivity type and have substantially flat top surfaces, a plurality of first semiconductor patterns are one-dimensionally arrayed on each word line along a length direction of the word line, the first semiconductor patterns have the first conductivity type or the second conductivity type, second semiconductor patterns having the first conductivity type are stacked on the first semiconductor patterns, an insulating layer is provided on the substrate having the second semiconductor patterns, the insulating layer fills gap regions between the word lines, gap regions between the first semiconductor patterns and gap regions between the second semiconductor patterns, a plurality of p

Abstract: A true bit line can extend across a memory cell area of the memory device in a first direction and a complementary bit line can extend across the memory cell area in a second direction opposing the first direction, wherein the true bit line and the complementary bit line comprising a bit line pair.

Abstract: A driver circuit for a PRAM (phase-change random access memory) device includes a write driver that generates a set/reset current in response to a set/reset pulse. In addition, a temperature compensator controls a pulse width of the set/reset pulse in response to a peripheral temperature of the PRAM device. For example, the temperature compensator maintains the pulse width to be substantially constant irrespective of the peripheral temperature. In another example, the temperature compensator decreases the pulse width for higher peripheral temperature.

Abstract: A method of biasing a memory cell array during a data writing operation and a semiconductor memory device, in which the semiconductor memory device includes: a memory cell array including a plurality of memory cells in which a first terminal of a memory cell is connected to a corresponding first line among a plurality of first lines and a second terminal of a memory cell is connected to a corresponding second line among a plurality of second lines; and a bias circuit for biasing a selected second line to a first voltage and non-selected second lines to a second voltage.

Abstract: Phase-changeable random access memory (PRAM) devices include a plurality of rows and columns of PRAM memory cells therein and at least one local bit line electrically coupled to a column of the PRAM memory cells. First and second bit line selection circuits are provided to increase the rate at which the at least one local bit line can be accessed and driven with a bit line signal. These first and second bit line selection circuits are configured to electrically connect first and second ends of the at least one local bit line to a global bit line during an operation to read data from a selected one of the PRAM memory cells in the column.

Abstract: A semiconductor memory device of one aspect includes a memory cell block including n global word lines, and corresponding m sub word lines for each of the n global word lines, where n and m are natural numbers. The memory device further includes a plurality of word line driving circuits which respectively control a voltage of the sub word lines according to a logic level of each corresponding global word line and inputted address signals, and a plurality of control circuits which transmit the address signals to the word line driving circuits or interrupt transmission of the address signals according to the logic level of the global word line. Each of the word line driving circuits includes a first transistor which maintains the voltage of the respective sub word line at a first voltage and a second transistor which maintains the voltage of the sub word line at the first voltage or a second voltage.

Abstract: A non volatile memory device and a memory system having the same are disclosed. The non volatile memory device may include a memory cell array having a plurality of non volatile memory cells, a DRAM interface for exchanging data, a command and an address with an external device, a controller for selecting one of the memory cells in response to the address and performing a control operation for one of outputting data of the selected memory cell to the external device in response to the command and storing data received from the external device, and a DRAM buffer memory. The DRAM buffer memory has dynamic memory cells, and each of the dynamic memory cells has one transistor with a floating body.

Abstract: In a firing method of a phase change memory device and a phase change memory capable of effectively performing a firing operation, the phase change memory device includes a plurality of memory cell array blocks, a counter clock generation unit, a decoding unit, and a driving unit. Each memory cell array block has phase change memory cells. The counter clock generation unit outputs first through third counter clock signals in response to an external clock signal and a firing mode signal, wherein the first through third counter clock signals have different cycles. The decoding unit, in response to the first through third counter clock signals, outputs a block address which selects one of the plurality of memory cell array blocks, word line addresses which enable word lines of the selected memory cell array block, and a redundant word line address which enables a redundant word line of the selected memory cell array block.

Abstract: In a nonvolatile memory device, a program operation is performed on a plurality of nonvolatile memory cells by programming data having a first logic state in a first group among a plurality of selected memory cells selected from the plurality of nonvolatile memory cells during a first program interval of the program operation, and thereafter, programming data having a second logic state different from the first logic state in a second group among the selected memory cells during a second program interval of the program operation after the first program interval.

Abstract: Provided are a phase-change memory device and method that maintains a resistance of a phase-change material in a set state within a constant resistance range; In the method, data is provided to a first phase-change memory cell and then it is first determined whether data stored in the first phase-change memory cell and the data provided to the first phase-change memory cell are identical.

Abstract: A method of biasing a memory cell array during a data writing operation and a semiconductor memory device are provided. The semiconductor memory device includes: a memory cell array including a plurality of memory cells in which a first terminal of a memory cell is connected to a corresponding first line among a plurality of first lines and a second terminal of a memory cell is connected to a corresponding second line among a plurality of second lines; and a bias circuit for biasing a selected second line to a first voltage and non-selected second lines to a second voltage.

Abstract: A drive circuit for a PRAM (phase-change random access memory) device includes a write driver that generates a set/reset current in response to a set/reset pulse. In addition, a temperature compensator controls a pulse width of the set/reset pulse in response to a peripheral temperature of the PRAM device. For example, the temperature compensator maintains the pulse width to be substantially constant irrespective of the peripheral temperature. In another example, the temperature compensator decreases the width for higher peripheral temperature.

Abstract: A phase change memory device comprises a memory cell array and a write driver circuit, and a column selection circuit. The memory cell array comprises a plurality of block units each connected between a corresponding pair of word line drivers. The write driver circuit comprises a plurality of write driver units each comprising a plurality of write drivers adapted to provide respective programming currents to a corresponding block unit among the plurality of block units. The column selection circuit is connected between the memory cell array and the write driver circuit and is adapted to select at least one of the plurality of memory blocks in response to a column selection signal to provide corresponding programming currents to the at least one of the plurality of memory blocks.

Abstract: A phase change memory device includes a memory array including a plurality of phase change memory cells, each phase change memory cell including a phase change material and a diode, a plurality of column selection transistors connecting bit lines connected to the phase change memory cells to corresponding data lines, and a control node connecting the data lines to a sense amplifier unit. In a write operation mode, control voltages obtained by boosting a first voltage are respectively applied to the control node and gates of the column selection transistors, and a ground voltage is applied to a word line of a selected one of the phase change memory cells. In a standby mode, word lines and bit lines connected to the phase change memory cells of the memory array are maintained at the same voltage.

Abstract: A method for programming a phase-change memory array and circuit of a phase-change memory device, each having a plurality of phase-change memory cells, may enable all the phase-change memory cells therein to be changed or set at a set resistance state, and may reduce the time needed to change the phase-change memory array to the set resistance state. In the method, a set current pulse having first through nth stages may be applied to the cells of the array to change the cells to the set resistance state. A minimum current level of the set current pulse applied to the phase-change memory cells in any stage may be higher than a reference current level for the cells of the array. A given current level of the set current pulse may be sequentially reduced from stage to stage.

Abstract: The layout method for a semiconductor device includes locating a plurality of first bit line selection circuits at a first side of a variable resistive memory cell block, and locating a plurality of second bit line selection circuits at a second side of the variable resistive memory cell block opposite the first side. The method further includes connecting the first bit line selection circuits with respective odd-numbered local bit lines of the variable resistive memory cell block, and connecting the second bit line selection circuits with respective even-numbered local bit lines of the variable resistive memory cell block. The method still further includes selectively connecting respective odd-numbered local bit lines to a global bit line using the first bit line selection circuits, and selectively connecting respective even-numbered local bit lines to the global bit line using the second bit line selection circuits.

Abstract: In a firing method of a phase change memory device and a phase change memory capable of effectively performing a firing operation, the phase change memory device includes a plurality of memory cell array blocks, a counter clock generation unit, a decoding unit, and a driving unit. Each memory cell array block has phase change memory cells. The counter clock generation unit outputs first through third counter clock signals in response to an external clock signal and a firing mode signal, wherein the first through third counter clock signals have different cycles. The decoding unit, in response to the first through third counter clock signals, outputs a block address which selects one of the plurality of memory cell array blocks, word line addresses which enable word lines of the selected memory cell array block, and a redundant word line address which enables a redundant word line of the selected memory cell array block.

Abstract: A semiconductor memory device compensates leakage current. A plurality of memory cells is disposed at intersections of word lines and bit lines. A plurality of dummy cells is connected to at least one dummy bit line. A leakage compensation circuit is connected to the at least one dummy bit line that outputs a leakage compensation current to at least one of the bit lines. A read current supply circuit outputs a read current necessary for a read operation to at least one of the bit lines in response to a first control signal. The memory device is a phase-change memory device containing phase-change material. The semiconductor memory device compensates leakage current in a read operation and supplies the leakage compensation current to a selected bit line, thereby suppressing error operation occurrence caused by leakage current.

Abstract: A data read circuit and method for use in a semiconductor memory device that has a memory cell array are provided. The circuit includes a selector for selecting a unit cell within the memory cell array in response to an address signal; a clamping unit for supplying a clamp voltage having a level for a read operation to a bit line of the selected unit cell in response to a clamp control signal; a precharge unit for precharging a sensing node to a voltage having a power source level in response to a control signal of a first state in a precharge mode, and compensating through the sensing node for a reduced quantity of current at the bit line in response to a control signal of a second state in a data sensing mode; and a sense amplifier unit for comparing a level of the sensing node with a reference level, and for sensing data stored in the selected unit cell.

Abstract: A semiconductor memory device and a method of programming the same, the semiconductor memory device includes a plurality of memory cells, each of the memory cells having a plurality of phase change variable resistors and a selection transistor. Each of the phase change variable resistors has a first end connected to one of a plurality of bit lines and a second end connected to a drain of the selection transistor. The selection transistor has a gate connected to a word line and a source connected to a reference voltage. The memory device is programmed by activating a word line associated with a selected memory cell, thereby turning on the selection transistor, applying a reset pulse to bit lines of the selected memory cell, and applying a set pulse to selected bit lines of the selected memory cell.