Abstract: A nonvolatile memory device includes a nonvolatile memory cell, a read circuit and a control bias generating circuit. The nonvolatile memory cell has a resistance level that changes depending on stored data. The read circuit reads the resistance level of the nonvolatile memory cell by receiving a control bias and supplying the nonvolatile memory cell a read bias based on the control bias. The control bias generating circuit receives an input bias, generates the control bias based on the input bias and supplies the control bias to the read circuit. A slope of the control bias to the input bias is less than 1.

Abstract: A phase change memory device of one aspect includes a memory array including a plurality of phase change memory cells, a write boosting circuit, and a write driver. The write boosting circuit boosts a first voltage and outputs a first control voltage in response to a control signal in a first operation mode, and boosts the first voltage and outputs a second control voltage in response to the control signal in a second operation mode and a third operation mode. The write driver is driven by the first control voltage in the first operation mode and writes data to a selected memory cell of the memory array.

Abstract: In one aspect, a non-volatile memory includes a phase-change memory cell array which includes a plurality of normal phase-change memory cells and a plurality of pseudo one-time-programmable (OTP) phase-change memory cells, a write driver which writes data into the normal and pseudo OTP phase-change memory cells of the phase-change memory cell array, and an OTP controller which selectively disables the write driver.

Abstract: In a semiconductor memory device and method, phase-change memory cells are provided, each including a plurality of control transistors formed on different layers and variable resistance devices formed of a phase-change material. Each phase-change memory cell includes a plurality of control transistors formed on different layers, and a variable resistance device formed of a phase-change material. In one example, the number of the control transistors is two. The semiconductor memory device includes a global bit line; a plurality of local bit lines connected to or disconnected from the global bit line via local bit line selection circuits which correspond to the local bit lines, respectively; and a plurality of phase-change memory cell groups storing data while being connected to the local bit lines, respectively.

Abstract: A phase-change memory device is provided. The phase-change memory device includes a phase-change memory cell array including a first memory block having a plurality of phase-change memory cells each connected between each of a plurality of bit lines and a first word line, a second memory block having a plurality of phase-change memory cells each connected between each of the plurality of bit lines and a second word line, and first and second pull-down transistors pulling-down each voltage level of the first and the second word lines and sharing a node and a row driver including a first and a second pull-up transistor pulling-up each voltage level of the first and the second word lines.

Abstract: In one aspect, a semiconductor memory device includes a plurality of phase-change memory cells which are programmed according to a write current applied to the phase-change memory cells, a voltage boosting circuit which receives a first voltage and outputs a boosted voltage which is greater than the first voltage, and a write driver which receives the boosted voltage and which generates the write current from the boosted voltage. In another aspect, the write driver generates the write current corresponding to one of a set current pulse and a reset current pulse, and at least one of the set current pulse and the reset current pulse is gradually increased.

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: Disclosed is a nonvolatile memory device using a variable resistive element, and a data read circuit for use in variable resistive memory devices. More specifically, embodiments of the invention provide a data read circuit with one or more decoupling units to remove noise from one or more corresponding control signals. For instance, embodiments of the invention remove noise from a clamping control signal, a read bias control signal, and/or precharge signal. The disclosed decoupling units may be used alone or in any combination. Embodiments of the invention are beneficial because they can increase sensing margin and improve the reliability of read operations in memory devices with variable resistive elements.

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 method and device for driving the word lines of a phase change memory device is provided. The method may include applying a first voltage level to non-selected word lines and a second voltage level to selected word lines during a normal operational mode, and placing the word lines in a floating state during a standby operational mode. The phase change memory device may include a plurality of word line drive circuits for driving corresponding word lines, where each of the plurality of word line drive circuits includes a drive unit which sets a corresponding word line to a first voltage level or a second voltage level in response to a first control signal, and a mode selector which selectively applies the first voltage level to the driving unit according to an operational mode of the phase change memory device.

Abstract: A memory device includes a plurality of blocks, with each block having a respective array of memory cells and respective local word lines. The memory device also includes a respective switching device coupled between each local word line and a common voltage node. A global word line driver controls the respective switching devices to turn on for respective local word lines in a row across the blocks including an accessed memory cell. Thus, the common voltage node is in the current path of the accessed memory cell with minimized layout area and resistance of the current path.

Abstract: A phase change memory device includes a semiconductor substrate which includes a plurality of phase change memory cells, a plurality of local bit lines extending over the semiconductor substrate, each of the plurality of local bit lines being coupled to the plurality of phase change memory cells, and a plurality of global bit lines extending over the plurality of local bit lines, each of the plurality of global bit lines being selectively coupled to the plurality of local bit lines. The plurality of global bit lines are located at two or more different wiring line levels over the semiconductor substrate.

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: Disclosed is a phase-changeable memory device and a related method of reading data. The memory device is comprised of memory cells, a high voltage circuit, a precharging circuit, a bias circuit, and a sense amplifier. Each memory cell includes a phase-changeable material and a diode connected to a bitline. The high voltage circuit provides a high voltage from a power source. The precharging circuit raises the bitline up to the high voltage after charging the bitline up to the power source voltage. The bias circuit supplies a read current to the bitline by means of the high voltage. The sense amplifier compares a voltage of the bitline with a reference voltage by means of the high voltage, and reads data from the memory cell. The memory device is able to reduce the burden on the high voltage circuit during the precharging operation, thus assuring a sufficient sensing margin during the sensing operation.

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: Disclosed is a method of driving a multi-level variable resistive memory device. A method of driving a multi-level variable resistive memory device includes supplying a write current to a variable resistive memory cell so as to change resistance of the variable resistive memory cell, verifying whether or not changed resistance enters a predetermined resistance window, and supplying a write current having an increased or decreased amount from the write current supplied most recently on the basis of the verification result so as to change resistance of the variable resistive memory cell.

Abstract: A resistive memory device includes a memory core unit and a buffer memory for reducing overhead of a memory controller in a memory system. The buffer memory stores input data associated with a write command. The memory core unit includes resistive memory cells for storing the input data from the buffer memory. The buffer memory is comprised of a different type of memory cells from the resistive memory cells such that the different type of memory cells writes the input data with a faster speed than the resistive memory cells.

Abstract: A semiconductor memory device includes a plurality of cell array layers including a plurality of word lines extending in a first direction, a plurality of bit lines extending in a second direction that intersects the first direction, and a plurality of memory cells disposed at intersections of the word lines and the bit lines. Each of the word lines has a word line position, each of the bit lines has a bit line position, and each of the memory cells includes a variable resistance device in series with a diode. The cell array layers are arranged in layers in a third direction that is perpendicular to the first and second directions. The bit lines of each of the cell array layers having a same bit line position are connected to a common column selector transistor, or the word lines of the cell array layers having a same word line position are connected to a common word line driver.

Abstract: A PRAM includes a memory cell array of phase change memory cells, and a write circuit receiving an externally provided first voltage and supplying a write pulse for writing data to the memory cells in a normal operation mode. The write circuit also receives an externally provided second voltage higher than the first voltage and supplies a firing pulse to at least one firing-failed phase change memory cell.

Abstract: A semiconductor memory device includes a memory cell array, a mode setting circuit, a parity data generation unit, and a data error detection and correction unit. The memory cell array has a plurality of first memory banks for storing normal data, and a predetermined number of second memory banks less than the number of the first memory banks for storing parity data according to control of a first flag signal. The mode setting circuit sets the first flag signal and a second flag signal controlling based on whether a separate memory bank is used to store the parity data in the second memory banks. The parity data generation unit receives normal write data during a write operation, generates parity data with respect to the normal write data in response to the second flag signal, and outputs the normal data and the parity data.