摘要:
A new read scheme is provided for an MRAM bit having a pinned layer (fixed) and a storage layer (free) sandwiching a nonmagnetic spacer layer. By applying a magnetic field to the bit at least partially orthogonal to the easy axis of the bit, the magnetization direction of the storage layer can be partially rotated or canted without switching the logical state of the MRAM bit. The resistivity of the bit is measured (calculated based on a voltage/current relationship) in two ways: (i) with the magnetization direction of the storage layer partially rotated in a first direction and (ii) with the magnetization direction of the storage layer in its bi-stable orientation parallel to the easy axis. Those measures can then be used to compare and determine the logical state of the storage layer. For instance, if the canted resistivity is greater than the uncanted resistivity then the magnetization directions of the pinned and storage layer are parallel, and if the canted resistivity is less than the uncanted resistivity then the magnetization directions of the pinned and storage layer are opposite.
摘要:
A magneto-resistive memory system is presented that includes a radiation-hardened and low power memory cell. The magneto-resistive memory cell includes a word line select transistor in the cell to help eliminate unselected cell disturbances. Furthermore, the magneto-resistive memory cell includes a full-turn write word line that writes true and complimentary bit values using less current than previous cell architectures. The improved memory cell may be used in a memory system with precision current drivers and auto-zero sense amplifiers in order to further lower power and improve overall system reliability.
摘要:
In a process of making a magnetoresistive memory device, a mask layout is produced by use of any suitable design tool. The mask layout is laid out in grids having a central grid forming a central section and grids forming bit end sections, and the grids of the bit end sections are rectangles. A mask is made by use of the mask layout, and the mask has stepped bit ends. The mask is used to make a magnetic storage layer having tapered bit ends, to make a magnetic sense layer having tapered bit ends, and to make a non-magnetic layer having tapered bit ends. The non-magnetic layer is between the magnetic sense layer and the magnetic storage layer.
摘要:
In a method of fabricating a giant magnetoresistive (GMR) device a plurality of magnetoresistive device layers is deposited on a first silicon nitride layer formed on a silicon oxide layer. An etch stop is formed on the magnetoresistive device layers, and a second layer of silicon nitride is formed on the etch stop. The magnetoresistive device layers are patterned to define a plurality of magnetic bits having sidewalls. The second silicon nitride layer is patterned to define electrical contact portions on the etch stop in each magnetic bit. The sidewalls of the magnetic bits are covered with a photoresist layer. A reactive ion etch (RIE) process is used to etch into the first silicon nitride and silicon oxide layers to expose electrical contacts. The photoresist layer and silicon nitride layers protect the magnetoresistive layers from exposure to oxygen during the etching into the silicon oxide layer.
摘要:
In a method of fabricating a giant magnetoresistive (GMR) device a plurality of magnetoresistive device layers is deposited on a first silicon nitride layer formed on a silicon oxide layer. An etch stop is formed on the magnetoresistive device layers, and a second layer of silicon nitride is formed on the etch stop. The magnetoresistive device layers are patterned to define a plurality of magnetic bits having sidewalls. The second silicon nitride layer is patterned to define electrical contact portions on the etch stop in each magnetic bit. The sidewalls of the magnetic bits are covered with a photoresist layer. A reactive ion etch (RIE) process is used to etch into the first silicon nitride and silicon oxide layers to expose electrical contacts. The photoresist layer and silicon nitride layers protect the magnetoresistive layers from exposure to oxygen during the etching into the silicon oxide layer.
摘要:
A magnetic field sensing system includes one or more magnetoresistive random access memory (MRAM) cells, and may be configured to determine one or more of a presence, a magnitude, and a polarity of an external magnetic field incident upon an MRAM cell. In some examples, a control module of the system controls a write current source, or another device, to provide a write current through a write line associated with the MRAM cell to induce a magnetic field proximate to the MRAM cell. The magnetic field may be less than a magnetic switching threshold of the MRAM cell. After initiating the provision of the write current through the write line, the control module may determine a magnetic state of the MRAM cell, and determine a presence of an external magnetic field incident upon the MRAM cell based at least in part on the magnetic state of the MRAM cell.
摘要:
A system may include circuitry and a magnetoresistive random access memory (MRAM) die including at least one MRAM cell. The circuitry may be configured to detect attempted tampering with the MRAM die and generate a signal based on the detected attempted tampering. The signal may be sufficient to damage or destroy at least one layer of the at least one MRAM cell or a fuse electrically connected to a read line of the at least one MRAM cell.
摘要:
This disclosure is directed to techniques for generating a reference current based on a combinational logic function that is to be performed by a magnetic logic device. A comparator circuit may compare an amplitude of a read current that flows through the magnetic logic device and the reference current to generate a logic output value that corresponds to the logic output value when combinational logic function is applied to the input values. By selecting appropriate amplitudes for the reference current the magnetic logic device may be caused to implement different combinational logic functions.
摘要:
This disclosure is directed to a magnetic logic device for implementing a combinational logic function. The magnetic logic device may include a chain of at least two magnetoresistive devices electrically coupled in series comprising a first terminal located at a first end of the chain and a second terminal located at a second end of the chain. The magnetic logic device may further include a voltage source configured to apply a voltage between the first terminal and the second terminal of the chain of at least two magnetoresistive devices electrically coupled in series. The magnetic logic device may further include a logic output generator configured to generate a logic output value for a logic function based on a magnitude of a current produced at the second terminal of the chain in response to the applied voltage.
摘要:
A magnetic device is provided in one example that comprises a free layer having a magnetic anisotropy. The magnetic anisotropy is at least partially non-uniform. The magnetic device further comprises an antiferromagnetic layer adjacent to and weakly exchange coupled with the free layer, wherein the weak exchange coupling reduces the non-uniformity of the magnetic anisotropy of the free layer.