摘要:
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.
摘要:
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.
摘要:
A phase-change cell memory device includes a plurality of phase-change memory cells, an address circuit, a write driver, and a write driver control circuit. The phase-change memory cells each include a volume of material that is programmable between amorphous and crystalline states. The address circuit selects at least one of the memory cells, and the write driver generates a reset pulse current to program a memory cell selected by the address circuit into the amorphous state, and a set pulse current to program the memory cell selected by the address circuit into the crystalline state. The write driver control circuit varies at least one of a pulse width and a pulse count of at least one of the reset and set pulse currents according to a load between the write driver and the memory cell selected by the address circuit.
摘要:
A layout method is provided for a latch-up prevention circuit of a semiconductor memory device which includes the steps of: arranging a cell array at substantially the middle of the device; placing peripheral circuits next to both sides of the cell array; placing a plurality of pads on both sides of the cell array between the peripheral circuits and both edges of the device; and arranging guard rings beneath the plurality of pads. The layout method further includes a plurality of ESD protection transistors disposed axially along the direction as the plurality of pads between the plurality of pads and an edge of the device. And each of guard ring is a NWELL guard ring, and connected to a supply voltage and ground.
摘要:
A write driver circuit including a plurality of programmable fuses for a phase change memory device in which a write operation is correctly performed even in the case where a current output shift in a write current generation circuit; or in the case where a phase change memory cell has a phase change property shift due to an external factor or due a process change. The write driver circuit includes; a write current control unit for outputting a first or second level of voltage selected, by selecting one of a first or second programmable current path, based on whether a first or second selection pulse signal is applied; and a current driving unit for generating a write current controlled by the output voltage of the write current control unit. Each of the first and second programmable current paths includes fuses that can be programmed to adjusted their resistance to adjust the respective selected output voltage to compensate for a current output shift in a write current generation circuit or for a phase change memory cell has a phase change property shift.
摘要:
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.
摘要:
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 of a plurality of first lines and a second terminal of the memory cell is connected to a corresponding second line of a plurality of second lines; a bias circuit for biasing a selected second line of the second lines to a reference voltage and a non-selected second line to a first voltage; and a local word line address decoder applying the reference voltage or a pumping voltage corresponding to the first voltage to the bias circuit.
摘要:
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 of a plurality of first lines and a second terminal of the memory cell is connected to a corresponding second line of a plurality of second lines; a bias circuit for biasing a selected second line of the second lines to a reference voltage and a non-selected second line to a first voltage; and a local word line address decoder applying the reference voltage or a pumping voltage corresponding to the first voltage to the bias circuit.
摘要:
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.
摘要:
A write driver circuit including a plurality of programmable fuses for a phase change memory device in which a write operation is correctly performed even in the case where a current output shift in a write current generation circuit; or in the case where a phase change memory cell having a phase change property shift due to an external factor or due a process change. The write driver circuit includes a write current control unit for outputting a first or second level of voltage selected, by selecting one of a first or second programmable current path, based on whether a first or second selection pulse signal is applied; and a current driving unit for generating a write current controlled by the output voltage of the write current control unit. Each of the first and second programmable current paths includes fuses that can be programmed to adjust their resistance to adjust the respective selected output voltage to compensate for the current output shift in the write current generation circuit or for the phase change memory cell having the phase change property shift.