Magnetic random access memory and method for reading and writing the same

Abstract

The invention discloses a magnetic random access memory and a reading and writing method thereof, belonging to the field of non-volatile memory. A storage unit is switched between 1T-1MTJ and 2T-2MTJ storage unit arrays according to an external enable signal En. The 1T-1MTJ storage unit The array has a large storage density, and the 2T‑2MTJ memory cell array has high read reliability. During the reading process, when the NMOS transistor N1, NMOS transistor N3, NMOS transistor N5 and NMOS transistor N6 are turned on, and the NMOS transistor N2 and NMOS transistor N4 are turned off, the magnetic tunnel junctions MTJ_a and MTJ_b are data units, and the reading method is based on 2T ‑2MTJ cell structure; when NMOS transistor N1 (N2), NMOS transistor N4, NMOS transistor N5, NMOS transistor N6, NMOS transistor N7 are on, and NMOS transistor N2 (N1) and NMOS transistor N3 are off, the magnetic tunnel junction MTJ_a (MTJ_b) For the data unit, the reading method is based on the 1T‑1MTJ unit structure. The read-write method of the present invention enables the storage unit to be switched between the highly reliable 2T-2MTJ unit and the high-density 1T-1MTJ unit, is suitable for different application scenarios, and can assist in the judgment of read and write errors.

Description

technical field [0001] The invention relates to the technical field of non-volatile memory, in particular to a magnetic random access memory and a reading and writing method thereof. Background technique [0002] Magnetic random access memory is a new type of non-volatile information memory, which has the advantages of low power consumption, fast read and write speed, high reliability and compatibility with standard CMOS technology. With the continuous development of semiconductor technology, constantly updated electronic products have put forward higher requirements on the performance of memory, including higher density, higher read and write speed, and lower power consumption. [0003] A typical MRAM memory cell has two cell structures, 1T-1MTJ and 2T-2MTJ; among the 1T-1MTJ memory cells, the read circuit needs to introduce reference cells. The reference unit is usually composed of several magnetic tunnel junction MTJs, and the resistance window between the reference unit...

AI Technical Summary

Problems solved by technology

The reference unit is usually composed of several magnetic tunnel junctions MTJ, and the resistance window between the reference unit and the data unit is smaller than the high and low resistance window of the magnetic tunnel junction MTJ; at the same time, due to the temperature characteristics and voltage bias of the magnetic tunnel junction MTJ effect, which increases the difficulty of the design of the reference unit and the readout error rate of the readout circuit, which affects the reliability of the circuit

[0004] In order to solve the above problems, a memory cell structure of 2T-2MTJ is proposed. In the form of self-reference, the two magnetic tunnel junctions MTJ in the cell are always in the opposite storage state. Using this memory cell structure will improve the readout reliability of the memory. , but using two cells with complementary storage states to store 1bit data will increase the area of ​​the storage array

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