Voltage-controlled magnetoresistive random access memory and read control method therefor

Abstract

A voltage-controlled magnetoresistive random access memory and a read control method therefor. The voltage-controlled magnetoresistive random access memory comprises: a first comparison circuit, a first magnetic tunnel junction, and a second magnetic tunnel junction; the first magnetic tunnel junction is connected to a first input end of the first comparison circuit, and the second magnetic tunnel junction is connected to a second input end of the first comparison circuit; the first magnetic tunnel junction is configured to obtain a first reference resistance under the action of a first input pulse, the width of the first input pulse is greater than or equal to a steady-state width threshold, under the action of the first input pulse, the first magnetic tunnel junction obtains a resistance value in an orthogonal state as the first reference resistance, and the orthogonal state is that a difference between an included angle between a first magnetic direction of a free magnetic layer of the first magnetic tunnel junction and a second magnetic direction of a fixed magnetic layer and a right angle is less than a preset threshold; and the second magnetic tunnel junction is configured to read or write data.

Description

Voltage-controlled magnetoresistive random access memory and read control method Technical Field

[0001] The present invention relates to the field of voltage-controlled magnetoresistive random access memory, and in particular to a voltage-controlled magnetoresistive random access memory and a reading control method. Background Art

[0002] Magnetoresistive random access memory (MRAM) uses a magnetic tunnel junction (MTJ) structure for data storage. The MTJ consists of a fixed magnetic layer, a thin insulating tunnel spacer, and a free magnetic layer. The magnetic orientation of the fixed magnetic layer remains constant, while in voltage-controlled MRAM, the magnetic orientation of the free magnetic layer is controlled by voltage. If the magnetic orientation of the free magnetic layer is parallel to that of the fixed magnetic layer, the MTJ exhibits low resistance. If the magnetic orientation of the free magnetic layer is antiparallel to that of the fixed magnetic layer, the MTJ exhibits high resistance. The resistance of the MTJ changes as the magnetic orientation of the free magnetic layer flips. MRAM determines whether the stored data is 0 or 1 based on whether the resistance is high or low.

[0003] A plurality of magnetic tunnel junction structures are arranged in rows and columns in a magnetoresistive random access memory to form a storage array. During the read control process of the magnetoresistive random access memory, the output voltage or current of each magnetic tunnel junction structure is compared with a reference voltage or current to determine whether the state is 1 or 0. However, in the prior art, in the process of determining the state of the magnetic tunnel junction structure, the traditional design method usually uses multiple components such as resistors or transistors in series or parallel to form a reference resistor of a specified resistance value, or uses multiple magnetic tunnel junction structures in high resistance state and low resistance state in series or parallel to form a reference resistor of a specified resistance value, thereby obtaining a reference voltage or current. However, the above-mentioned method in the prior art requires the use of multiple components to obtain a reference resistor of a specific value, the memory cost is high, the control process is complicated, and when the external series or parallel circuit of the reference resistor changes or the ambient temperature changes, the reference resistor will change, causing the memory to fail to work properly.

[0004] Summary of the Invention

[0005] In order to solve the technical problems in the prior art of high cost, complex control process and inability to operate stably and normally, the present invention provides a voltage-controlled magnetoresistive random access memory and a read control method.

[0006] A first aspect of the present invention provides a voltage-controlled magnetoresistive random access memory, the voltage-controlled magnetoresistive random access memory comprising at least:

[0007] a first comparison circuit, a first magnetic tunnel junction, and a second magnetic tunnel junction;

[0008] The first magnetic tunnel junction is connected to the first input terminal of the first comparison circuit, and the second magnetic tunnel junction is connected to the second input terminal of the first comparison circuit;

[0009] The first magnetic tunnel junction is configured to obtain a first reference resistance under the action of a first input pulse, wherein the width of the first input pulse is greater than or equal to a steady-state width threshold. Under the action of the first input pulse, the first magnetic tunnel junction obtains a resistance value in an orthogonal state as the first reference resistance, wherein the orthogonal state is defined as a difference between an angle between a first magnetic direction of a free magnetic layer and a second magnetic direction of a fixed magnetic layer of the first magnetic tunnel junction and a right angle being less than a preset threshold.

[0010] The second magnetic tunnel junction is used for reading or writing data.

[0011] In some embodiments, the first magnetic tunnel junction includes a first magnetic layer, a second magnetic layer, and a first insulating layer, and the second magnetic tunnel junction includes a third magnetic layer, a fourth magnetic layer, and a second insulating layer;

[0012] The first magnetic layer is connected to the first input end, and the third magnetic layer is connected to the second input end.

[0013] In some embodiments, the first magnetic layer may be a fixed magnetic layer, and the second magnetic layer may be a free magnetic layer;

[0014] The third magnetic layer may be a fixed magnetic layer, and the fourth magnetic layer may be a free magnetic layer;

[0015] The fixed magnetic layer has a first magnetic direction, and the free magnetic layer has a second magnetic direction, wherein the first magnetic direction is fixed and the second magnetic direction is variable.

[0016] In some embodiments, the second magnetic tunnel junction operating state includes at least a high resistance state and a low resistance state.

[0017] In the high resistance state, the first magnetic direction of the fixed magnetic layer and the second magnetic direction of the free magnetic layer are in an anti-parallel state;

[0018] In the low resistance state, the first magnetic direction and the second magnetic direction are in the same parallel state.

[0019] In some embodiments, the magnetic switching probability of the second magnetic layer in the first magnetic tunnel junction and the width of the first input pulse have a first nonlinear relationship;

[0020] The first nonlinear relationship includes an attenuated oscillation stage and a stable stage. If the pulse width is less than the steady-state width threshold, the second magnetic reversal probability oscillates sinusoidally attenuated between the maximum oscillation probability value and the minimum oscillation probability value; if the pulse width is greater than or equal to the pulse width threshold, the second magnetic reversal probability is stable at 50%.

[0021] In some embodiments, a first nonlinear relationship between the magnetic reversal probability of the second magnetic layer in the first magnetic tunnel junction and the width of the first input pulse is obtained, and a pulse width threshold is determined based on the first nonlinear relationship; and the pulse width of the first input pulse is set to be greater than or equal to the pulse width threshold.

[0022] In some embodiments, the voltage-controlled magnetoresistive random access memory further comprises at least a plurality of transistors.

[0023] A first input pulse is input into the free magnetic layer of the first magnetic tunnel junction via a transistor. If the resistance of the first magnetic tunnel junction is stable at a reference resistance, a read signal is input into the free magnetic layer of the second magnetic tunnel junction via a transistor. The output signals of the first magnetic tunnel junction and the second magnetic tunnel junction are respectively input into the first input terminal and the second input terminal via a plurality of transistors connected in series. The circuits connected to the two input terminals of the first comparison circuit are arranged symmetrically.

[0024] In some embodiments, the voltage-controlled magnetoresistive random access memory includes at least a master timing control, a storage array, a decoder control circuit, a read / write circuit, an IO,

[0025] The storage array is composed of a plurality of second magnetic tunnel structures. The number of first magnetic tunnel structures is multiple, and one first magnetic tunnel structure corresponds to a row of second magnetic tunnel structures, a column of second magnetic tunnel structures, or one second magnetic tunnel structure.

[0026] A second aspect of the present invention provides a voltage-controlled magnetoresistive random access memory read control method, comprising at least:

[0027] inputting a first input pulse to the first magnetic tunnel junction at a first preset time;

[0028] Inputting a read control signal to the second magnetic tunnel junction at a second preset time, wherein the first magnetic tunnel junction is in an orthogonal state at the second preset time;

[0029] The output signals of the first magnetic tunnel junction and the second magnetic tunnel junction are connected to the first input terminal and the second input terminal of the first comparison circuit respectively, and the read data is obtained from the output terminal of the first comparison circuit;

[0030] Among them, the difference between the first preset time and the second preset time is greater than or equal to the decay time period, the width of the first input pulse is greater than or equal to the steady-state width threshold, and the orthogonal normal state is that the difference between the angle between the first magnetic direction of the free magnetic layer and the second magnetic direction of the fixed magnetic layer of the first magnetic tunnel junction and the right angle is less than the preset threshold.

[0031] In some embodiments, a historical oscillation time of the first magnetic tunnel junction is obtained, an arrival time of an enable signal in a read control signal is used as a second preset time, and the second preset time is advanced by the historical oscillation time to calculate the first preset time.

[0032] The present invention provides a voltage-controlled magnetoresistive random access memory and a read control method thereof, which only require the use of a single magnetic tunnel junction to implement a reference resistor, resulting in a low cost memory. Furthermore, the flip state of the voltage-controlled magnetoresistive random access memory has a resistance value between a high resistance value and a low resistance value, meaning that a single component can directly meet the resistance range requirements of the reference resistor. The resistance value of the reference resistor is completely controlled by the input voltage, eliminating the need for repeated adjustment and facilitating ease of use. Furthermore, because the first and second magnetic tunnel junctions connected in parallel at the input of the comparison circuit are the same components, they will experience the same changes when the ambient temperature changes or other interference occurs. At this time, due to the parallel relationship, the effects of the aforementioned changes on the resistance, voltage, or current will offset each other, thereby ensuring the operational stability of the voltage-controlled magnetoresistive random access memory.

[0033] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0035] FIG1 is a schematic diagram of a data reading circuit of a magnetic tunnel junction in the prior art;

[0036] FIG2 is a schematic diagram of a reference resistor in the prior art;

[0037] FIG3( a ) is a schematic diagram of another reference resistor in the prior art;

[0038] FIG3( b ) is a schematic diagram of another reference resistor in the prior art;

[0039] FIG4 is a schematic diagram of a data reading circuit of a magnetic tunnel junction provided by the present invention;

[0040] FIG5 is a schematic diagram of a first nonlinear relationship provided by the present invention;

[0041] Figure 6 (a)-(c) are schematic diagrams showing changes in the working state of the magnetic tunnel junction provided by the present invention;

[0042] FIG7 is a schematic diagram of a magnetic tunnel junction according to the present invention being converted into an orthogonal state;

[0043] FIG8 is a waveform diagram of a magnetic tunnel junction provided by the present invention when it is converted to an orthogonal state;

[0044] FIG9 is a data reading circuit diagram of a magnetic tunnel junction provided by the present invention;

[0045] FIG10 is a signal waveform diagram of data reading provided by the magnetic tunnel junction provided by the present invention;

[0046] Figure 11 (a)-(c) are schematic diagrams of a voltage-controlled magnetoresistive random access memory provided by the present invention;

[0047] FIG12 is a flow chart of a voltage-controlled magnetoresistive random access memory read control method provided by the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0050] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0051] Magnetoresistive random access memory (MRAM) uses a magnetic tunnel junction structure for data storage. The MTM consists of a fixed magnetic layer, a thin insulating tunnel spacer, and a free magnetic layer. The magnetic orientation of the fixed magnetic layer remains constant, while voltage-controlled MRAM uses a voltage to control the magnetic orientation of the free magnetic layer. If the magnetic orientation of the free magnetic layer is parallel to that of the fixed magnetic layer, the MTM has a low resistance. If the magnetic orientation of the free magnetic layer is antiparallel to that of the fixed magnetic layer, the MTM has a high resistance. The resistance of the MTM changes when the magnetic orientation of the free magnetic layer flips. MRAM determines whether the stored data is 0 or 1 based on whether the resistance is high or low.

[0052] The circuitry of a memory cell in a magnetoresistive random access memory (MRAM) typically consists of an NMOS transistor integrated with a magnetic tunnel junction structure. The NMOS transistor's gate is connected to the memory array's word line, while its source is connected to the fixed magnetic layer of the MTM structure. The memory array's bit line (BL) is connected to the MTM's free magnetic layer. During a MRAM read, varying voltages are applied between the bit line and source, generating a write current through the MTM structure. As the magnitude and direction of the write current change, the magnetization of the free magnetic layer in the MTM structure shifts, causing the tunneling resistance of the MTM structure to change between high and low resistance states, effectively writing and storing 0s and 1s. During a MRAM write, current flows from the bit line and is output through the MTM structure. The output voltage determines whether the data stored in the memory cell is 0 or 1.

[0053] As shown in FIG1 , during the read control process of a magnetoresistive random access memory, the output voltage or current of the magnetic tunnel junction structure is compared with a reference voltage or current by a comparator to determine whether the state is 1 or 0. In order to achieve the judgment of the 0 and 1 states, the resistance value of the reference resistor should be between the resistance values ​​corresponding to the high resistance state and the low resistance state of the magnetic tunnel junction structure. In the process of judging the state of the magnetic tunnel junction structure, there are two types of methods in the prior art to form a reference resistor with a resistance value within a specific range. The first type of method is to use a series or parallel connection of multiple components such as adjustable resistors or transistors to form a reference resistor, as shown in FIG2 ; the second type of method is to use a plurality of magnetic tunnel junction structures in a high resistance state or a low resistance state to form a reference resistor in series or in parallel, as shown in FIG3 (a) and (b) which are schematic diagrams of two magnetic tunnel junction structures connected in series and in parallel. However, the above two methods require the use of multiple components to obtain a reference resistor of a specific value, which results in a high memory cost. The resistance values ​​of the components constituting the reference resistor need to be adjusted before each use. Moreover, during normal operation, the resistance value of the resistor constituted by the components may change due to the influence of parallel circuits, ambient temperature, and other interferences, thereby deviating from the reference resistor and causing the magnetoresistive random access memory to malfunction.

[0054] In view of the above problems existing in the prior art, the present invention provides a voltage-controlled magnetoresistive random access memory, as shown in FIG3 , wherein the voltage-controlled magnetoresistive random access memory at least comprises:

[0055] a first comparison circuit, a first magnetic tunnel junction, and a second magnetic tunnel junction;

[0056] The first magnetic tunnel junction is connected to the first input terminal of the first comparison circuit, and the second magnetic tunnel junction is connected to the second input terminal of the first comparison circuit;

[0057] The first magnetic tunnel junction is configured to obtain a first reference resistance under the action of a first input pulse, wherein the width of the first input pulse is greater than or equal to a steady-state width threshold. Under the action of the first input pulse, the first magnetic tunnel junction obtains a resistance value in an orthogonal state as the first reference resistance, wherein the orthogonal state is defined as a difference between an angle between a first magnetic direction of a free magnetic layer and a second magnetic direction of a fixed magnetic layer of the first magnetic tunnel junction and a right angle being less than a preset threshold.

[0058] The second magnetic tunnel junction is used for reading or writing data.

[0059] The voltage-controlled magnetoresistive random access memory provided by the present invention only requires one magnetic tunnel junction to realize a reference resistor, and the cost of the memory is low. Moreover, the flip state of the voltage-controlled magnetoresistive random access memory has a resistance value between a high resistance value and a low resistance value, that is, a single component can directly meet the resistance range requirement of the reference resistor. The resistance value of the reference resistor is completely controlled by the input voltage, and no repeated adjustment is required, which is simple to use. In addition, because the first magnetic tunnel junction and the second magnetic tunnel junction connected in parallel at the input of the comparison circuit are the same components, when the ambient temperature changes or other interference occurs, the two will produce the same changes. At this time, due to the parallel relationship, the effects of the above changes on the resistance, voltage or current will offset each other, thereby ensuring the stability of the operation of the voltage-controlled magnetoresistive random access memory.

[0060] Specifically, the first comparison circuit can be used to compare the analog signals of the first magnetic tunnel junction and the second magnetic tunnel junction to obtain a digital output signal. The first comparison circuit can be, but is not limited to, an operational amplifier. The first comparison circuit can be any circuit structure in the prior art that implements comparison of two input signals. The first comparison circuit includes a first input terminal and a second input terminal, the first magnetic tunnel junction being connected to the first input terminal of the first comparison circuit, and the second magnetic tunnel junction being connected to the second input terminal of the first comparison circuit. As an optional embodiment, if the first comparison circuit is used to compare voltage signals, it collects a first voltage signal at the connection between the first magnetic tunnel junction and the first input terminal, collects a second voltage signal at the connection between the second magnetic tunnel junction and the second input terminal, compares the magnitudes of the first and second voltage signals, and outputs a value of 0 or 1. As another optional embodiment, if the first comparison circuit is used to compare current signals, it collects a first current signal at the connection between the first magnetic tunnel junction and the first input terminal, collects a second current signal at the connection between the second magnetic tunnel junction and the second input terminal, compares the magnitudes of the first and second current signals, and outputs a value of 0 or 1.

[0061] The first and second magnetic tunnel junctions have identical structures. The first magnetic tunnel junction includes a first magnetic layer, a second magnetic layer, and a first insulating layer, while the second magnetic tunnel junction includes a third magnetic layer, a fourth magnetic layer, and a second insulating layer. The first magnetic layer may be a fixed magnetic layer, and the second magnetic layer may be a free magnetic layer. Alternatively, the first magnetic layer may be a free magnetic layer, and the second magnetic layer may be a fixed magnetic layer. The third magnetic layer may be a fixed magnetic layer, and the fourth magnetic layer may be a free magnetic layer. Alternatively, the third magnetic layer may be a free magnetic layer, and the fourth magnetic layer may be a fixed magnetic layer. The first and second insulating layers are thin insulating tunneling layers, positioned between the first and second magnetic layers and the third and fourth magnetic layers, respectively. The magnetic orientation of the fixed magnetic layer is fixed, while the magnetic orientation of the free magnetic layer is dependent on an input magnetic tunnel pulse. The first magnetic layer is connected to the first input terminal, and the third magnetic layer is connected to the second input terminal. The fixed magnetic layer has a first magnetic orientation, and the free magnetic layer has a second magnetic orientation. The first magnetic orientation is fixed, while the second magnetic orientation is variable.

[0062] The working state of the first magnetic tunnel junction includes at least an orthogonal state, and the working state of the second magnetic tunnel junction includes at least a high resistance state and a low resistance state; preferably, in the orthogonal state, the first magnetic direction and the second magnetic direction are in an orthogonal state, that is, the angle between the first magnetic direction and the second magnetic direction is 90°. As another optional embodiment, the orthogonal state is that the difference between the angle between the first magnetic direction and the second magnetic direction and the right angle is less than a preset threshold value, for example, the preset threshold value is 10°, the angle between the first magnetic direction and the second magnetic direction is 85°, and the difference from the right angle is 5°. Since the difference is less than the preset threshold value, the first magnetic tunnel junction operates in an orthogonal state; in the high resistance state, the first magnetic direction and the second magnetic direction are in an antiparallel state, that is, the angle between the first magnetic direction and the second magnetic direction is 180°; in the low resistance state, the first magnetic direction and the second magnetic direction are in a parallel state in the same direction, that is, the angle between the first magnetic direction and the second magnetic direction is 0°.

[0063] A first input pulse is input from the second magnetic layer into the first magnetic tunnel junction. The magnetic reversal probability of the second magnetic layer in the first magnetic tunnel junction and the width of the first input pulse have a first nonlinear relationship. The first nonlinear relationship is the relationship between pulse width and reversal probability. The first nonlinear relationship includes a decaying oscillation phase and a steady-state phase. If the pulse width is less than a steady-state width threshold, the second magnetic reversal probability exhibits a sinusoidal decaying oscillation between a maximum oscillation probability value and a minimum oscillation probability value. In an optional embodiment, the maximum oscillation probability is 100% and the minimum oscillation probability is 0, as shown in FIG5 . If the pulse width is greater than or equal to the pulse width threshold and there are no other external signals, the second magnetic reversal probability stabilizes at 50%, and the resistance of the magnetic tunnel junction is between parallel and antiparallel states. The first nonlinear relationship is obtained, and a pulse width threshold is determined based on the first nonlinear relationship. The pulse width of the first input pulse is set to be greater than or equal to the pulse width threshold. In a specific embodiment, the first nonlinear relationship is obtained as shown in FIG5 , and the pulse width at which the reversal probability stabilizes at 50% is determined based on the first nonlinear relationship as the pulse width threshold.

[0064] Preferably, the flip probability of the second magnetic layer is matched based on the magnitude relationship between the width of the first input pulse and the pulse width threshold, the flip angle of the second magnetic layer is matched based on the flip probability of the second magnetic layer, and the reference resistance of the first magnetic tunnel junction is calculated based on the flip angle of the second magnetic layer. The first magnetic tunnel junction is used to obtain a first reference resistance under the action of a first input pulse, the width of the first input pulse is greater than or equal to a steady-state width threshold, and under the action of the first input pulse, the first magnetic tunnel junction obtains a resistance value in an orthogonal state as a first reference resistance, and the orthogonal state is that the difference between the angle between the first magnetic direction of the free magnetic layer and the second magnetic direction of the fixed magnetic layer of the first magnetic tunnel junction and the right angle is less than a preset threshold. If the width of the first input pulse is greater than the pulse width threshold, the reference resistance of the first magnetic tunnel junction is calculated using the following formula: R(90)=G T (1+P 2 cos(90)).

[0065] The flip angle of the free magnetic layer of the magnetic tunnel junction oscillates and decays according to the width of the input pulse, as shown in Figure 6. As shown in Figure 6(a), in the initial state, the magnetic tunnel junction is in a low resistance state; if a voltage is applied to the magnetic tunnel junction, as the pulse width changes, the magnetic direction of the free magnetic layer flips, as shown in Figure 6(b), from the initial state to the orthogonal state to the high resistance state shown in Figure 6(c). As shown in Figures 7 and 8, applying a width MTJ voltage V MTJ Under the action of MTJ voltage, the resistance value of the first magnetic tunnel junction is at a high resistance value R AP and low resistance R P The oscillations between the two are attenuated, and the resistance value R(90) is stabilized in the orthogonal state. The memory provided by the present invention uses a structure identical to that of the magnetic tunnel junction in the read / write array to generate a reference resistance to offset interference. A voltage signal is used to control the magnetic tunnel junction to be in an intermediate flip state, thereby obtaining a reference resistance between a low resistance value and a high resistance value, thereby improving the stability of the memory and reducing the cost of the memory.

[0066] The second magnetic tunnel junction is used to read or write data, wherein a second input pulse is input into the second magnetic tunnel junction from the fourth magnetic layer. A magnetic reversal probability of the fourth magnetic layer in the second magnetic tunnel junction and a width of the second input pulse have a second nonlinear relationship; the first nonlinear relationship and the second nonlinear relationship may be the same or different.

[0067] As shown in FIG9 , the voltage-controlled magnetoresistive random access memory includes at least a plurality of transistors. The reference voltage signal is input into the free magnetic layer of the first magnetic tunnel junction via the transistors. The read signal is input into the free magnetic layer of the second magnetic tunnel junction via the transistors. The output signals of the first magnetic tunnel junction and the second magnetic tunnel junction are respectively input into the first input terminal and the second input terminal via a plurality of transistors connected in series. The circuits connected to the two input terminals of the first comparison circuit are symmetrically arranged. As shown in FIG10 , a first input pulse, a reference voltage signal REF_EN, is input into the first magnetic tunnel junction. If the resistance of the first magnetic tunnel junction is stable at the reference resistance R(90), the enable information in the read control signal is received and input into the free magnetic layer of the second magnetic tunnel junction. Thus, when the second magnetic tunnel junction is in a high resistance state, a high level is output to represent a signal 1; otherwise, a low level is output to represent a signal 0.

[0068] As an optional embodiment, as shown in Figures 11(a)-(c), the voltage-controlled magnetoresistive random access memory also includes at least a main timing control, a storage array, a decoder control circuit, a read-write circuit, and an IO. The storage array is composed of a plurality of second magnetic tunnel structures. The number of first magnetic tunnel structures is multiple, which can correspond to a row of second magnetic tunnel structures, as shown in Figure 11(a), or can correspond to a column of second magnetic tunnel structures, as shown in Figure 11(b), or can correspond to one second magnetic tunnel structure, as shown in Figure 11(c).

[0069] A second embodiment of the present invention provides a voltage-controlled magnetoresistive random access memory read control method, as shown in FIG12 . The read control method at least includes:

[0070] inputting a first input pulse to the first magnetic tunnel junction at a first preset time;

[0071] Inputting a read control signal to the second magnetic tunnel junction at a second preset time, wherein the first magnetic tunnel junction is in an orthogonal state at the second preset time;

[0072] The output signals of the first magnetic tunnel junction and the second magnetic tunnel junction are connected to the first input terminal and the second input terminal of the first comparison circuit respectively, and the read data is obtained from the output terminal of the first comparison circuit;

[0073] Among them, the difference between the first preset time and the second preset time is greater than or equal to the decay time period, the width of the first input pulse is greater than or equal to the steady-state width threshold, and the orthogonal normal state is that the difference between the angle between the first magnetic direction of the free magnetic layer and the second magnetic direction of the fixed magnetic layer of the first magnetic tunnel junction and the right angle is less than the preset threshold.

[0074] The reading control method provided by the present invention first uses a first input pulse to adjust the first magnetic tunnel junction from an unstable attenuation state to a stable orthogonal state before the reading control signal takes effect, thereby obtaining the resistance in the orthogonal state as a reference resistance; after the reference resistance is generated, it is input to the second magnetic tunnel junction according to the reading control signal at a second preset time, thereby realizing data reading in the second magnetic tunnel junction based on the reference resistance and the comparison circuit.

[0075] As an optional embodiment, a historical oscillation time of the first magnetic tunnel junction is obtained, and the second preset time is determined based on the historical oscillation time and the read control signal. Specifically, the arrival time of the enable signal in the read control signal is used as the second preset time, and the second preset time is advanced by the historical oscillation time to calculate the first preset time.

[0076] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A voltage-controlled magnetoresistive random access memory, characterized in that: include: The voltage-controlled magnetoresistive random access memory at least comprises: a first comparison circuit, a first magnetic tunnel junction, and a second magnetic tunnel junction; The first magnetic tunnel junction is connected to a first input terminal of the first comparison circuit, and the second magnetic tunnel junction is connected to a second input terminal of the first comparison circuit; The first magnetic tunnel junction is used to obtain a first reference resistance under the action of a first input pulse, the width of the first input pulse is greater than or equal to a steady-state width threshold, and under the action of the first input pulse, the first magnetic tunnel junction obtains a resistance value in an orthogonal state as the first reference resistance, and the orthogonal state is that the difference between the angle between the first magnetic direction of the free magnetic layer and the second magnetic direction of the fixed magnetic layer of the first magnetic tunnel junction and the right angle is less than a preset threshold; The second magnetic tunnel junction is used for reading or writing data.

2. The voltage-controlled magnetoresistive random access memory according to claim 1, characterized in that: The first magnetic tunnel junction includes a first magnetic layer, a second magnetic layer and a first insulating layer, and the second magnetic tunnel junction includes a third magnetic layer, a fourth magnetic layer and a second insulating layer; The first magnetic layer is connected to the first input end, and the third magnetic layer is connected to the second input end.

3. The voltage-controlled magnetoresistive random access memory according to claim 2, characterized in that: The first magnetic layer may be a fixed magnetic layer, and the second magnetic layer may be a free magnetic layer; The third magnetic layer may be a fixed magnetic layer, and the fourth magnetic layer may be a free magnetic layer; The fixed magnetic layer has a first magnetic direction, and the free magnetic layer has a second magnetic direction, the first magnetic direction is fixed, and the second magnetic direction is variable.

4. The voltage-controlled magnetoresistive random access memory according to claim 1, wherein: The second magnetic tunnel junction working state includes at least a high resistance state and a low resistance state. In the high resistance state, the first magnetic direction of the fixed magnetic layer and the second magnetic direction of the free magnetic layer are in an anti-parallel state; In the low resistance state, the first magnetic direction and the second magnetic direction are in the same parallel state.

5. The voltage-controlled magnetoresistive random access memory according to claim 1, wherein: The magnetic switching probability of the second magnetic layer in the first magnetic tunnel junction and the width of the first input pulse have a first nonlinear Sexual relations; The first nonlinear relationship includes an attenuated oscillation stage and a stable stage. If the pulse width is less than the steady-state width threshold, the second magnetic reversal probability oscillates sinusoidally attenuated between the maximum oscillation probability value and the minimum oscillation probability value; if the pulse width is greater than or equal to the pulse width threshold, the second magnetic reversal probability is stabilized at 50%.

6. The voltage-controlled magnetoresistive random access memory according to claim 1, characterized in that: Acquire a first nonlinear relationship between a magnetic switching probability of a second magnetic layer in the first magnetic tunnel junction and a width of the first input pulse, and determine a pulse width threshold based on the first nonlinear relationship; The pulse width of the first input pulse is set to be greater than or equal to the pulse width threshold.

7. The voltage-controlled magnetoresistive random access memory according to claim 1, characterized in that: The voltage-controlled magnetoresistive random access memory at least comprises a plurality of transistors. A first input pulse is input into the free magnetic layer of the first magnetic tunnel junction via a transistor. If the resistance of the first magnetic tunnel junction is stabilized at a reference resistance, a read signal is input into the free magnetic layer of the second magnetic tunnel junction via a transistor. Output signals of the first magnetic tunnel junction and the second magnetic tunnel junction are respectively input into the first input terminal and the second input terminal via a plurality of transistors connected in series. The circuits connected to the two input terminals of the first comparison circuit are arranged symmetrically.

8. The voltage-controlled magnetoresistive random access memory according to claim 1, wherein: The voltage-controlled magnetoresistive random access memory at least includes a main timing control, a storage array, a decoder control circuit, a read-write circuit, and an IO. The storage array is composed of a plurality of second magnetic tunnel structures. The number of first magnetic tunnel structures is multiple, and one first magnetic tunnel structure corresponds to a row of second magnetic tunnel structures, a column of second magnetic tunnel structures, or one second magnetic tunnel structure.

9. A voltage-controlled magnetoresistive random access memory read control method, characterized in that: The reading control method at least comprises: Inputting a first input pulse to the first magnetic tunnel junction at a first preset time; Inputting a read control signal to the second magnetic tunnel junction at a second preset time, wherein the first magnetic tunnel junction is in an orthogonal state at the second preset time; The output signals of the first magnetic tunnel junction and the second magnetic tunnel junction are connected to the first input terminal and the second input terminal of the first comparison circuit respectively, and the read data is obtained from the output terminal of the first comparison circuit; Among them, the difference between the first preset time and the second preset time is greater than or equal to the attenuation time period, the width of the first input pulse is greater than or equal to the steady-state width threshold, and the orthogonal normal state is that the difference between the angle between the first magnetic direction of the free magnetic layer and the second magnetic direction of the fixed magnetic layer of the first magnetic tunnel junction and the right angle is less than the preset threshold.

10. The voltage controlled magnetoresistive random access memory read control method according to claim 9, characterized in that: The historical oscillation time of the first magnetic tunnel junction is obtained, the arrival time of the enable signal in the read control signal is taken as the second preset time, and the second preset time is advanced by the historical oscillation time to calculate the first preset time.

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