Boosted gate voltage programming for spin-torque MRAM array
First Claim
1. A spin-torque MRAM cell array comprising:
- a plurality of spin-torque MRAM cells arranged in rows and columns, each spin-torque MRAM cell comprising;
a magnetic tunnel junction element, anda select switching device having a drain terminal connected to a first terminal of the magnetic tunnel junction element;
a plurality of local word lines, each local word line associated with one row of the plurality of spin-torque MRAM cells and connected to a gate terminal of the select switching device of each spin-torque MRAM cell on each row to control activation and deactivation of the select switching device; and
a plurality of gate voltage boosting circuits, each gate voltage boosting circuit placed between an associated global word line of a plurality of global word lines and an associated local word line of the plurality of local word lines to boost a local word line voltage applied to a gate of the select switching device of the selected spin-torque MRAM cell during writing of a first level to the magnetic tunnel junction element of a selected spin-torque MRAM cell when activated by a local word line control signal wherein a gate capacitance of the select switching devices of unselected spin-torque MRAM cells sharing a local word line function as boost capacitors to provide a boost voltage for the gate boosting circuit.
3 Assignments
0 Petitions
Accused Products
Abstract
A gate voltage boosting circuit provides a voltage boost to a gate of a select switching MOS transistor of a spin-torque MRAM cell to prevent a programming current reduction through an MTJ device of the spin-torque MRAM cell. A spin-torque MRAM cell array is composed of spin-torque MRAM cells that include a MTJ element and a select switching device. A local word line is associated with one row of the plurality of spin-torque MRAM cells and is connected to a gate terminal of the select switching devices of the row of MRAM cells to control activation and deactivation. One gate voltage boosting circuit is placed between an associated global word line and an associated local word line. The gate voltage boosting circuits boost a voltage of a gate of the selected switching device during writing of a logical “1” to the MTJ element of a selected spin-torque MRAM cell.
33 Citations
30 Claims
-
1. A spin-torque MRAM cell array comprising:
-
a plurality of spin-torque MRAM cells arranged in rows and columns, each spin-torque MRAM cell comprising; a magnetic tunnel junction element, and a select switching device having a drain terminal connected to a first terminal of the magnetic tunnel junction element; a plurality of local word lines, each local word line associated with one row of the plurality of spin-torque MRAM cells and connected to a gate terminal of the select switching device of each spin-torque MRAM cell on each row to control activation and deactivation of the select switching device; and a plurality of gate voltage boosting circuits, each gate voltage boosting circuit placed between an associated global word line of a plurality of global word lines and an associated local word line of the plurality of local word lines to boost a local word line voltage applied to a gate of the select switching device of the selected spin-torque MRAM cell during writing of a first level to the magnetic tunnel junction element of a selected spin-torque MRAM cell when activated by a local word line control signal wherein a gate capacitance of the select switching devices of unselected spin-torque MRAM cells sharing a local word line function as boost capacitors to provide a boost voltage for the gate boosting circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A spin-torque magnetic random access memory device comprising
a plurality of spin-torque MRAM cell arrays arranged in a plurality of groups, each spin-torque MRAM array comprising: -
a plurality of spin-torque MRAM cells arranged in rows and columns, each spin-torque MRAM cell comprising; a magnetic tunnel junction element, and a select switching device having a drain terminal connected to a first terminal of the magnetic tunnel junction element; a plurality of local word lines, each local word line associated with one row of the plurality of spin-torque MRAM cells and connected to a gate terminal of the select switching device of each spin-torque MRAM cell on each row to control activation and deactivation of the select switching device; and a plurality of gate voltage boosting circuits, each gate voltage boosting circuit placed between an associated global word line of a plurality of global word lines and an associated local word line of the plurality of local word lines to boost a local word line voltage applied to a gate of the select switching device of the selected spin-torque MRAM cell during writing of a first level to the magnetic tunnel junction element of a selected spin-torque MRAM cell when activated by a local word line control signal wherein a gate capacitance of the select switching devices of unselected spin-torque MRAM cells sharing a local word line function as boost capacitors to provide a boost voltage for the gate boosting circuit. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A method for writing a selected spin-torque MRAM cell in an array of spin-torque MRAM cells to a first level comprising the steps of:
-
providing a plurality of spin-torque MRAM cells arranged in rows and columns, each spin-torque MRAM cell comprising; a magnetic tunnel junction element, and a select switching device having a drain terminal connected to a first terminal of the magnetic tunnel junction element; providing a plurality of local word lines, each local word line associated with one row of the plurality of spin-torque MRAM cells and connected to a gate terminal of the select switching device of each spin-torque MRAM cell on each row to control activation and deactivation of the select switching device; and providing a plurality of gate voltage boosting circuits, each gate voltage boosting circuit placed between an associated global word line of a plurality of global word lines and an associated local word line of the plurality of local word lines to boost a local word line voltage applied to a gate of the select switching device of the selected spin-torque MRAM cell during writing of a first level to the magnetic tunnel junction element of a selected spin-torque MRAM cell when activated by a local word line control signal; activating the global word line associated with the selected spin-torque MRAM cell at a first time; activating the local word line control signal to effectively connect the global word line associated with the selected spin-torque MRAM cell and the local word line associated with the selected spin-torque MRAM cell at the first time; applying a data input signal as the first level to a bit line associated with the selected spin-torque MRAM cell to generate a current to program the magnetic tunnel junction element of the selected spin-torque MRAM cell to the first level at the first time; precharging the gate capacitance of the select switching devices of the unselected spin-torque MRAM cells; and deactivating the local word line control signal to effectively disconnect the global word line associated with the selected spin-torque MRAM cell and the local word line associated with the selected spin-torque MRAM cell at a second time to float the local word line associated with the selected spin-torque MRAM cell for boosting the associated local word line to a higher voltage level to compensate for a rise of a voltage at a source of the select switching device of the selected spin-torque MRAM cell.
-
-
22. A method for forming a spin-torque MRAM cell array comprising the steps of:
-
forming a plurality of spin-torque MRAM cells arranged in rows and columns, wherein forming each spin-torque MRAM cell comprises the steps of; forming a magnetic tunnel junction element, and forming a select switching device having a drain terminal connected to a first terminal of the magnetic tunnel junction element; forming a plurality of local word lines, wherein forming each local word line comprises the steps of associating each local word line with one row of the plurality of spin-torque MRAM cells, and connecting each word line to a gate terminal of the select switching device of each spin-torque MRAM cell on its associated row to control activation and deactivation of the select switching device; and forming a plurality of gate voltage boosting circuits, wherein forming each gate voltage boosting circuit comprises the steps of; placing each gate voltage boosting circuit between an associated global word line of a plurality of global word lines and an associated local word line of the plurality of local word lines to boost a local word line voltage applied to a gate of the selected switching device during writing of a first level to the magnetic tunnel junction element of a selected spin-torque MRAM cell when activated by a local word line control signal, wherein a gate capacitance of the select switching devices of unselected spin-torque MRAM cells sharing a local word line function as boost capacitors to provide a boost voltage for the gate boosting circuit. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
-
Specification