Storage unit of magnetic random access memory and data multi-state memory control method

Abstract

The embodiment of the invention discloses a storage unit of a magnetic random access memory and a data multi-state storage control method. The storage unit comprises a magnetic tunnel junction and two N-channel metal oxide semiconductor (NMOS) transistors, wherein the magnetic tunnel junction is connected in series between the two NMOS transistors; wherein a source electrode of the first NMOS transistor is connected with a writing bit line, a drain electrode is connected with a source electrode line after passing through a bottom electrode, and a grid electrode is connected with a writing word line; the drain electrode of the second NMOS transistor is connected with a read bit line, the source electrode is connected with the top electrode, and the grid electrode is connected with a read word line; the magnetic tunnel junction is of a multi-ellipse crossed structure, and the magnetic moment direction of a fixed layer in the magnetic tunnel junction, the current direction of a bottom electrode and the long axis direction of multiple ellipses form an angle of 0-90 degrees. According to the embodiment of the invention, the storage unit with a specific MTJ structure is adopted, and a plurality of different resistance states in a single memory cell are realized through current control, so that multi-bit memory of a single device is really realized, and memory density is effectively improved.

Description

technical field [0001] The invention relates to the technical field of magnetic storage, in particular to a storage unit of a magnetic random access memory and a data multi-state storage control method. Background technique [0002] With the continuous upgrading of the software and hardware performance of electronic equipment, the market puts forward higher requirements for the storage density and storage speed of the memory. Magnetic random access memory (MRAM, Magnetic Random Access Memory) is often used in electronic devices with a process technology of 28nm or below at the present stage. Magnetic random access memory combines the high-speed reading and writing capabilities of static random access memory (SRAM) and the advantages of high integration of dynamic random access memory (DRAM). It also has low power consumption, long data storage time and unlimited rewriting It can be used for both large-scale data storage and logical computing, and has been proven to be the m...

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Problems solved by technology

However, both of the above two methods in the prior art have some obvious defects: the method of reducing the size of MTJ has high requirements on the preparation process, and it is difficult to meet the production equipment, process accuracy and yield rate, and the cost is high and difficult to achieve; and In the existing technology, the CMOS devices connected to the periphery of the SOT device will also occupy a large area. Simply reducing the size of the MTJ does not significantly improve the integration level, and cannot effectively increase the storage density.

The method of stacking or series MTJ is actually realized by integrating multiple devices. On the one hand, it does not really realize the multi-bit storage of a single device. On the other hand, the realization of multi-bit storage requires specific array and circuit cooperation, design and preparation. The process is more complicated, it is difficult to produce and it is difficult to write data in one step

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