Abstract: In one embodiment, the semiconductor device includes a non-volatile memory cell array, a write buffer configured to store data being written into the non-volatile memory cell array, and a write address buffer configured to store a write address associated with each data stored in the write buffer. An output circuit is configured to selectively output one of data read from the non-volatile memory array and data from the write buffer. A by-pass control circuit is configured to control the output circuit based on whether an input read address matches a valid write address stored in the write address buffer. An invalidation unit is configured to invalidate an address stored in the write address buffer if the stored write address matches an input write address.

Abstract: A memory device includes a memory array having a plurality of rows and columns of nonvolatile memory cells (e.g., PRAM cells) therein and a first plurality of local bit lines electrically coupled to a corresponding first plurality of columns of memory cells in the memory array. A first plurality of bit line selection circuits are also provided, which are responsive to bit line selection signals. A first plurality of bit line discharge circuits are electrically connected to respective ones of the first plurality of local bit lines. A bit line discharge control circuit is provided to drive the first plurality of bit line discharge circuits with equivalent bit line discharge signals during an operation to read data from a selected one of the first plurality of local bit lines.

Abstract: In a phase-change random access memory (PRAM) device, a write operation is performed by applying a set pulse to failed PRAM cells. The set pulse comprises a plurality of stages sequentially decreasing from a first current magnitude to a second current magnitude. The first current magnitude or the second current magnitude varies from one write loop to another.

Abstract: A phase change memory device may include a memory cell array, a write driver, and/or a control unit. The memory cell array may include a plurality of memory cells. The write driver may be configured to provide a program current to the memory cell array for setting a state of a phase change material to program a selected memory cell. The write driver may be configured to provide the program current such that the program current has a plurality of steps. The control unit may be configured to receive step information for adjusting a magnitude and a width of each step of the program current during a test operation and provide the step information to the write driver during a normal operation.

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: A method programs a phase change memory device. The method comprises receiving program data for selected memory cells; generating bias voltages based on reference cells; sensing read data stored in a selected memory cell by supplying the selected memory cell with verification currents determined by the bias voltages; determining whether the read data is identical to the program data; and upon determining that the program data for one or more of the selected memory cells is not identical to the corresponding read data, iteratively applying a write current to the one or more selected memory cells.

Abstract: Apparatus and systems that use phase-change memory devices are provided. The phase-change memory devices may include multiple phase-change memory cells and a reset pulse generation circuit configured to output multiple sequential reset pulses. Each sequential reset pulse is output to a corresponding one of multiple reset lines. Multiple write driver circuits are coupled to corresponding phase change memory cells and to a corresponding one of the reset lines of the reset pulse generation circuit.

Abstract: An apparatus, a nonvolatile memory device and a nonvolatile memory system include an array of nonvolatile variable resistive memory (VRM) cells and a writing driver circuit having a pulse selection circuit, a current control circuit, and a current drive circuit. The current control circuit receives a bias voltage, outputs a control signal at a second level during an enable duration of the reset pulse when the data is at a first level, and outputs a control signal at a first level during an enable duration of the set pulse when the data is at a second level. The current drive circuit outputs writing current to the phase-change memory array during the enable duration of the reset pulse or the set pulse. The writing driver circuit can select the reset pulse or the set pulse according to the logic level of the data, and control the level of current applied to the phase-change memory array according to the reset pulse or the set pulse.

Abstract: In a phase-change random access memory (PRAM) device, a write operation is performed by applying a set pulse to failed PRAM cells. The set pulse comprises a plurality of stages sequentially decreasing from a first current magnitude to a second current magnitude. The first current magnitude or the second current magnitude varies from one write loop to another.

Abstract: A memory system includes a resistance variable memory device, and a memory controller for controlling the resistance variable memory device. The resistance variable memory device includes a memory cell connected to a bitline, a high voltage circuit adapted to generate a high voltage from an externally provided power source voltage, where the high voltage is higher than the power source voltage, a precharging circuit adapted to charge the bitline to the power source voltage and further charge the bitline to the high voltage, a bias circuit adapted to provide a read current to the bitline with using the high voltage, and a sense amplifier adapted to detect a voltage level of the bitline with using the high voltage.

Abstract: A phase change memory device may include a memory cell array, a write driver, and/or a control unit. The memory cell array may include a plurality of memory cells. The write driver may be configured to provide a program current to the memory cell array for setting a state of a phase change material to program a selected memory cell. The write driver may be configured to provide the program current such that the program current has a plurality of steps. The control unit may be configured to receive step information for adjusting a magnitude and a width of each step of the program current during a test operation and provide the step information to the write driver during a normal operation.

Abstract: According to one embodiment, at least a portion of the phase change material including a first crystalline phase is converted to one of a second crystalline phase and an amorphous phase. The second crystalline phase transitions to the amorphous phase more easily than the first crystalline phase. For example, the first crystalline phase may be a hexagonal closed packed structure, and the first crystalline phase may be a face centered cubic structure.

Abstract: Apparatus and systems that use phase-change memory devices are provided. The phase-change memory devices may include multiple phase-change memory cells and a reset pulse generation circuit configured to output multiple sequential reset pulses. Each sequential reset pulse is output to a corresponding one of multiple reset lines. Multiple write driver circuits are coupled to corresponding phase change memory cells and to a corresponding one of the reset lines of the reset pulse generation circuit.

Abstract: A phase change memory device has a word line driver layout which allows for a reduction in the size a core area of the device. In one aspect, phase change memory device includes a plurality of memory cell blocks sharing a word line, and a plurality of word line drivers driving the word line. Each of the word line drivers includes a precharge device for precharging the word line and a discharge device for discharging the word line, and where the precharge device and the discharge device are alternately located between the plurality of memory cell blocks.

Abstract: The phase change memory device includes a plurality of memory banks, a plurality of local conductor lines connected to the plurality of memory banks, at least one global conductor line connected to the plurality of local conductor lines, and at least one repair control circuit configured to selectively replace at least one of the at least one global conductor line with at least one redundant global conductor line and configured to selectively replace at least one of the plurality of local conductor lines with at least one redundant local conductor line.

Abstract: A semiconductor memory device having an efficient core structure for multi-writing includes a data input/output line, a plurality of memory banks each comprising a plurality of memory cells, a first global bit line and a second global bit line which are shared by the plurality of memory banks, and a first write driver and a second write driver which are connected with the data input/output line and provide a program current to the plurality of memory banks through the first and second global bit lines, respectively. Each memory bank includes a first cell area connected with the first global bit line and a second cell area connected with the second global bit line.

Abstract: According to one embodiment, at least a portion of the phase change material including a first crystalline phase is converted to one of a second crystalline phase and an amorphous phase. The second crystalline phase transitions to the amorphous phase more easily than the first crystalline phase. For example the first crystalline phase may be a hexagonal closed packed structure and the first crystalline phase may be a face centered cubic structure.

Abstract: Provided is a phase change random access (PRAM) memory. The PRAM may include a memory cell array having a plurality of phase change memory cells, and a data read circuit including a compensation unit and a sense amplifier, the compensation unit configured to provide a sensing node with a compensation current to compensate for a decrease in a level of the sensing node caused by a current flowing through one of the plurality of phase change memory cells, and the sense amplifier configured to compare a level of the sensing node with a reference level and output a result of the comparison.

Abstract: A phase-change random access memory (PRAM) device capable of reducing a resistance of a word line may include a plurality of main word lines of a semiconductor memory device or PRAM bent n times in a layer different from a layer in which a plurality of sub-word lines are disposed. The semiconductor memory device or PRAM may further include jump contacts for connecting the plurality of cut sub-word lines. In a PRAM device including the plurality of main word lines and the plurality of sub-word lines being in different layers, the number of jump contacts for connecting the plurality of main word lines to a transistor of a sub-word line decoder is the same in each sub-word line or the plurality of main word lines are bent several times so that a parasitic resistance on a word line and power consumption may be reduced, and a sensing margin may be increased.

Abstract: A semiconductor memory device includes at least one write global bit line connected to a plurality of local bit lines and at least one read global bit line connected to the local bit lines. The phase-change memory device having the write global bit line and the read global bit line suppress coupling noise generated during a read-while-write operation.