阅读说明：本技术 基于拓扑自旋的电控磁各向异性磁性随机存储器 (Electric control magnetic anisotropy magnetic random access memory based on topological spin ) 是由 聂天晓 方蟾 于 2021-06-04 设计创作，主要内容包括：本发明提供一种基于拓扑自旋的电控磁各向异性磁性随机存储器,包括：薄膜结构、电压源以及电流源；所述薄膜结构包括：从上到下依次叠加的顶电极层、反铁磁层、参考层、氧化物层、自由层、拓扑绝缘体层、高介电衬底以及底电极层；所述电压源的一端与所述顶电极层连接；所述电压源的另一端与所述底电极层连接；所述电流源与所述拓扑绝缘体层连接。通过电流源向拓扑绝缘体薄膜层通入电流,使得自由层铁磁薄膜的磁性翻转；铁磁磁各向异性与拓扑表面态的电压调控效应,产生自旋轨道转矩效应使得相邻自由层铁磁薄膜的磁矩发生偏转；极大地降低了自由层铁磁薄膜磁性翻转所需的阈值电流,从而实现超低功耗的信息存储。(The invention provides an electric control magnetic anisotropy magnetic random access memory based on topological spin, which comprises: a thin film structure, a voltage source and a current source; the thin film structure includes: the device comprises a top electrode layer, an antiferromagnetic layer, a reference layer, an oxide layer, a free layer, a topological insulator layer, a high-dielectric substrate and a bottom electrode layer which are sequentially stacked from top to bottom; one end of the voltage source is connected with the top electrode layer; the other end of the voltage source is connected with the bottom electrode layer; the current source is connected to the topological insulator layer. Current is introduced into the topological insulator thin film layer through a current source, so that the magnetism of the free layer ferromagnetic thin film is reversed; the ferromagnetic anisotropy and the voltage regulation effect of the topological surface state generate a spin orbit torque effect to deflect the magnetic moment of the ferromagnetic thin film of the adjacent free layer; the threshold current required by the magnetic reversal of the ferromagnetic thin film of the free layer is greatly reduced, so that the information storage with ultra-low power consumption is realized.)

1. An electrically controlled magnetic anisotropic magnetic random access memory based on topological spins, comprising: a thin film structure, a voltage source and a current source;

the thin film structure includes: the device comprises a top electrode layer, an antiferromagnetic layer, a reference layer, an oxide layer, a free layer, a topological insulator layer, a high-dielectric substrate and a bottom electrode layer which are sequentially stacked from top to bottom;

one end of the voltage source is connected with the top electrode layer; the other end of the voltage source is connected with the bottom electrode layer; the current source is connected to the topological insulator layer.

2. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

the thickness of any of the top electrode layer, the antiferromagnetic layer, the reference layer, the oxide layer, the free layer, the topological insulator layer, the high dielectric substrate, and the bottom electrode layer is on the order of nanometers.

3. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

any two of the top electrode layer, the antiferromagnetic layer, the reference layer, the oxide layer, the free layer, the topological insulator layer, the high dielectric substrate, and the bottom electrode layer are coupled with maximum surface contact therebetween.

4. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

the current source is used for outputting a positive current or a negative current to the topological insulator layer so as to drive the free layer to carry out read-write operation.

5. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

the voltage source is used for applying controllable voltage to the high dielectric substrate so as to realize the control of the perpendicular magnetic anisotropy of the free layer ferromagnetic film;

the voltage source is also configured to apply a controllable voltage to the topological insulator layer to enhance the fraction of spin-momentum locked surface states of the topological insulator layer in the conducting channel and reduce the current required for the ferromagnetic thin film magnetic moment flipping of the free layer.

6. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

when the current source inputs currents in different directions to the topological insulator thin film layer, the magnetic moments of the ferromagnetic thin film of the free layer are correspondingly overturned in different directions, and the topological insulator thin film is based on a tunneling magneto-resistance effect; the anti-parallel working state or the parallel working state of the memory is determined by the relative directions of the magnetic moments of the ferromagnetic films of the free layer and the reference layer.

7. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

the reference layer has a fixed magnetization direction.

8. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 7,

the magnetization direction of the free layer is parallel or antiparallel to the magnetization direction of the reference layer.

9. The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of claim 1,

the antiferromagnetic layer is used to enhance the magnetic anisotropy and magnetization direction of the reference layer.

10. The electrically controlled magnetic anisotropy magnetic random access memory based on topological spins according to any of claims 1 to 9,

the free layer is one or any combination of CoFeB, FeB, CoFeB, Fe and a heusler alloy.

Technical Field

The invention relates to the technical field of electronic memories, in particular to an electric control magnetic anisotropy magnetic random access memory based on topological spinning.

Background

In the conventional Spin Orbit Torque (SOT) based writing technology, a thin film made of heavy metals such as platinum, tantalum, tungsten and the like is added below a free layer of a magnetic tunnel junction MTJ, and when a current is introduced into the heavy metal layer, an in-plane charge current flowing into the heavy metal layer is converted into a vertical Spin current by a Spin hall effect. Spin current then flows into the overlying ferromagnetic free layer and drives the magnetization of the free layer to switch by spin-orbit torque. Spin-orbit torque magnetic random access memory SOT-MRAM generates more conduction electrons with the same spin state than spin-transfer torque magnetic random access memory STT-MRAM and injects them into the ferromagnetic layer. The generated torque is stronger, and the magnetization direction of the free layer is easier to turn over, so that the processing speed is higher, and the power consumption is lower. In the research of memory, how to reduce the power consumption of memory devices has been the research direction of those skilled in the art.

Therefore, how to provide a magnetic memory scheme to achieve magnetic random access memory with lower power consumption is an urgent technical problem to be solved by those skilled in the art.

Disclosure of Invention

The invention provides an electric control magnetic anisotropy magnetic random access memory based on topological spinning, which can realize magnetic random access memory with lower power consumption.

The invention provides an electric control magnetic anisotropy magnetic random access memory based on topological spin, which comprises: a thin film structure, a voltage source and a current source;

the thin film structure includes: the device comprises a top electrode layer, an antiferromagnetic layer, a reference layer, an oxide layer, a free layer, a topological insulator layer, a high-dielectric substrate and a bottom electrode layer which are sequentially stacked from top to bottom;

one end of the voltage source is connected with the top electrode layer; the other end of the voltage source is connected with the bottom electrode layer; the current source is connected to the topological insulator layer.

Further, a thickness of any one of the top electrode layer, the antiferromagnetic layer, the reference layer, the oxide layer, the free layer, the topological insulator layer, the high dielectric substrate, and the bottom electrode layer is on the order of nanometers.

Further, any two of the top electrode layer, the antiferromagnetic layer, the reference layer, the oxide layer, the free layer, the topological insulator layer, the high dielectric substrate, and the bottom electrode layer are coupled with maximum surface contact therebetween.

Further, the current source is used for outputting a positive current or a negative current to the topological insulator layer to drive the free layer to perform read and write operations.

Further, the voltage source is used for applying controllable voltage to the high dielectric substrate so as to realize the control of the perpendicular magnetic anisotropy of the free layer ferromagnetic film;

the voltage source is also configured to apply a controllable voltage to the topological insulator layer to enhance the fraction of spin-momentum locked surface states of the topological insulator layer in the conducting channel and reduce the current required for the ferromagnetic thin film magnetic moment flipping of the free layer.

Further, when the current source inputs currents in different directions to the topological insulator thin film layer, the magnetic moments of the ferromagnetic thin films of the free layer correspondingly flip in different directions, and the tunneling magnetoresistance effect is used for realizing the switching of the magnetic moments of the ferromagnetic thin films of the free layer; the anti-parallel working state or the parallel working state of the memory is determined by the relative directions of the magnetic moments of the ferromagnetic films of the free layer and the reference layer.

Further, the reference layer has a fixed magnetization direction.

Further, the magnetization direction of the free layer is parallel or antiparallel to the magnetization direction of the reference layer.

Further, the antiferromagnetic layer serves to enhance the magnetic anisotropy and magnetization direction of the reference layer.

Further, the free layer is one or any combination of CoFeB, FeB, CoFeB, iron (Fe) and heusler alloy.

According to the electric control magnetic anisotropy magnetic random access memory based on topological spin, current is introduced to the topological insulator thin film layer through the current source, so that the magnetism of the free layer ferromagnetic thin film is turned over; meanwhile, a voltage source is utilized to apply voltage to the multilayer film structure, and a spin orbit torque effect is generated by combining ferromagnetic anisotropy and a voltage regulation effect of a topological surface state, so that the magnetic moment of the ferromagnetic thin film of the adjacent free layer is deflected; and the electrically controlled magnetic anisotropy and the spin orbit torque effect in the topological insulator greatly reduce the threshold current required by the magnetic turning of the ferromagnetic thin film on the free layer, thereby realizing the information storage with ultra-low power consumption, overcoming the problems of large working current and long turning time of the common spin orbit torque magnetic memory, having simple preparation process of the thin film structure and relatively low cost of the constituent materials, and being beneficial to the production and the application of the related magnetic random memory device.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a structure of an electrically controlled magnetic anisotropic magnetic random access memory based on topological spin according to an embodiment of the present invention;

FIG. 2 is a second schematic diagram of a structure of an electrically controlled anisotropic magnetic random access memory based on topological spin according to an embodiment of the present invention;

FIG. 3 is a third schematic diagram of a structure of an electrically controlled anisotropic magnetic random access memory based on topological spin according to an embodiment of the present invention.

The reference numbers are as follows:

thin film structure 110, voltage source 120, current source 130, top electrode layer 101, antiferromagnetic layer 102, reference layer 103, oxide layer 104, free layer 105, topological insulator layer 106, high dielectric substrate 107, bottom electrode layer 108.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The electrically controlled magnetic anisotropic magnetic random access memory based on topological spins of the present invention is described below with reference to fig. 1 to 3.

FIG. 1 is a schematic diagram of a structure of an electrically controlled magnetic anisotropic magnetic random access memory based on topological spin according to an embodiment of the present invention; FIG. 2 is a second schematic diagram of a structure of an electrically controlled anisotropic magnetic random access memory based on topological spin according to an embodiment of the present invention; FIG. 3 is a third schematic diagram of a structure of an electrically controlled anisotropic magnetic random access memory based on topological spin according to an embodiment of the present invention.

In a specific embodiment of the present invention, an embodiment of the present invention provides an electrically controlled magnetic anisotropic magnetic random access memory based on topological spin, including: thin film structure 110, voltage source 120, and current source 130; the thin film structure includes: a top electrode layer 101, an antiferromagnetic layer 102, a reference layer 103, an oxide layer 104, a free layer 105, a topological insulator layer 106, a high dielectric substrate 107, and a bottom electrode layer 108, which are stacked in this order from top to bottom; one end of the voltage source is connected with the top electrode layer; the other end of the voltage source is connected with the bottom electrode layer; the current source is connected to the topological insulator layer.

According to the embodiment of the invention, the controllable voltage is applied to the high dielectric substrate to regulate the perpendicular magnetic anisotropy of the free layer, so that the free layer is easy to overturn by the spin current. Meanwhile, the surface state of the topological material of the topological insulator layer can be regulated by voltage, the spin orbit torque of the topological insulator layer is enhanced by selecting proper voltage, the threshold current of magnetic moment overturning can be further reduced, the overturning time of an MTJ (magnetic tunnel junction) is reduced, the size of a transistor is reduced, and the storage density is increased.

Specifically, the thickness of any one of the top electrode layer, the antiferromagnetic layer, the reference layer, the oxide layer, the free layer, the topological insulator layer, the high dielectric substrate, and the bottom electrode layer is on the order of nanometers. The thin film structure is a multilayer thin film structure and comprises a top electrode layer, a pinning thin film layer (namely an anti-ferromagnetic layer), a ferromagnetic thin film layer (reference layer), an oxide thin film layer (namely an oxide layer), a ferromagnetic thin film layer (free layer), a topological insulator thin film layer (namely a topological insulator layer) and a bottom electrode layer below the substrate, wherein the thin film layers are thin films with nanometer thicknesses, and the thicknesses can be 0.5nm-2 nm.

Further, any two of the top electrode layer, the antiferromagnetic layer, the reference layer, the oxide layer, the free layer, the topological insulator layer, the high dielectric substrate, and the bottom electrode layer are coupled with maximum surface contact therebetween. In the multilayer thin film structure, the layers are in maximum surface contact with each other, so that the coupling effect between the layers can play the maximum role.

Further, the current source is used for outputting a positive current or a negative current to the topological insulator layer to drive the free layer to perform read and write operations. Specifically, a current source inputs current to the memory, the input current is converted into unidirectional spin current due to the strong spin Hall effect of the topological insulator film of the topological insulator layer, and a spin orbit torque effect is generated to deflect the magnetic moment of the ferromagnetic film of the adjacent free layer, wherein the deflection direction depends on the direction of the input current. Based on the tunneling magnetoresistance effect, the relative direction of the magnetic moments of the ferromagnetic films of the free layer and the reference layer determines whether the memory is in a high-resistance (anti-parallel) or low-resistance state (parallel) working state. Thereby enabling the magnetic random access memory structure to perform memory write operations by inputting current. The current source inputs charge current to the topological insulator thin film layer, so that spin current is generated in the topological insulator thin film layer, and the spin current induces spin orbit torque to be generated in the free layer ferromagnetic thin film, so that the magnetic torque of the free layer ferromagnetic thin film is deflected.

On the basis of the embodiment, the voltage source is used for applying controllable voltage to the high dielectric substrate so as to realize the control of the perpendicular magnetic anisotropy of the free layer ferromagnetic thin film; the voltage source is also configured to apply a controllable voltage to the topological insulator layer to enhance the fraction of spin-momentum locked surface states of the topological insulator layer in the conducting channel and reduce the current required for the ferromagnetic thin film magnetic moment flipping of the free layer.

Specifically, the antiferromagnetic layer is one or any combination of platinum manganese (PtMn), iridium manganese (IrMn), palladium manganese (PdMn) and iron manganese (FeMn), and the thickness can be 1nm-10 nm. The common element proportion of PtMn can be Pt50Mn50, Pt20Mn80, Pt25Mn75 or Pt75Mn 25; the common element mixture ratio of IrMn is Ir50Mn50, Ir20Mn80 or Ir25Mn75 and other materials; the common element proportion of PdMn is Pd50Mn50, Pd90Mn10 or Pd75Mn25 and other materials; the common element proportion of FeMn is Fe50Mn50 or Fe80Mn20, and the numbers in the materials represent the percentage of the elements.

Further, when the current source inputs currents in different directions to the topological insulator thin film layer, the magnetic moments of the ferromagnetic thin films of the free layer correspondingly flip in different directions, and the tunneling magnetoresistance effect is used for realizing the switching of the magnetic moments of the ferromagnetic thin films of the free layer; the relative direction of the magnetic moments of the ferromagnetic films of the free layer and the reference layer determines that the memory is in an anti-parallel working state or a parallel working state, and the reference layer has a fixed magnetization direction. The magnetization direction of the free layer is parallel or antiparallel to the magnetization direction of the reference layer. An antiferromagnetic layer is used to enhance the magnetic anisotropy and magnetization direction of the reference layer.

Further, the free layer is one or any combination of CoFeB, FeB, CoFeB, iron (Fe) and heusler alloy. The common element proportion of the cobalt, iron and boron can be Co20Fe60B20, Co40Fe40B20 or Co60Fe20B 20; the common element proportion of the iron and the boron can be Fe80B 20; the common element proportion of the cobalt and iron can be Co50Fe50, Co20Fe80 or Co80Fe20 and other materials; the heusler alloy may be cobalt iron aluminum (Co2FeAl) or cobalt manganese silicon (Co2 MnSi); the numbers in the above materials represent percentages of elements.

The oxide layer refers to a thin film layer formed by an insulator material such as a metal oxide, and may be one or any combination of magnesium oxide, aluminum oxide, magnesium aluminum oxide, hafnium oxide, and tantalum oxide, such as magnesium oxide (MgO), aluminum oxide (Al2O3), magnesium metaaluminate (MgAl2O4), and the like, and the specific thickness may be 0.2nm to 1.5 nm.

It should also be noted that the voltage is applied to the high dielectric substrate at the same time, and the surface state of the topological insulator layer can be regulated and controlled through the piezoelectric effect, so that the spin orbit torque is enhanced, and the current required by the magnetic moment reversal of the free layer ferromagnetic film is further reduced.

According to the electric control magnetic anisotropy magnetic random access memory based on topological spinning, the current is introduced to the topological insulator thin film layer by using the current source, so that the magnetism of the free layer ferromagnetic thin film is turned; meanwhile, a voltage source is utilized to apply proper voltage to the multilayer film structure, and the threshold current required by the magnetic turning of the ferromagnetic thin film of the free layer is greatly reduced by combining the ferromagnetic anisotropy and the voltage regulation effect of the topological surface state.

Specifically, fig. 2 shows a situation before the magnetic moment of the ferromagnetic thin film of the free layer is flipped, fig. 3 shows a situation after the magnetic moment of the ferromagnetic thin film of the free layer is flipped, as shown in fig. 2 and fig. 3, when a current source inputs currents in different directions to the topological insulator thin film layer, the magnetic moment of the ferromagnetic thin film of the free layer can be flipped in different directions, and based on the tunneling magnetoresistance effect, the relative directions of the magnetic moments of the ferromagnetic thin film of the free layer and the reference layer determine that the memory is in a high-resistance (anti-parallel) or low-resistance state (parallel) operating state.

According to the electric control magnetic anisotropy magnetic random access memory based on topological spinning, provided by the embodiment of the invention, current is introduced to the topological insulator thin film layer through the current source, so that the magnetism of the free layer ferromagnetic thin film is turned; meanwhile, a voltage source is utilized to apply voltage to the multilayer film structure, and a spin orbit torque effect is generated by combining ferromagnetic anisotropy and a voltage regulation effect of a topological surface state, so that the magnetic moment of the ferromagnetic thin film of the adjacent free layer is deflected; and the electrically controlled magnetic anisotropy and the spin orbit torque effect in the topological insulator greatly reduce the threshold current required by the magnetic turning of the ferromagnetic thin film on the free layer, thereby realizing the information storage with ultra-low power consumption, overcoming the problems of large working current and long turning time of the common spin orbit torque magnetic memory, having simple preparation process of the thin film structure and relatively low cost of the constituent materials, and being beneficial to the production and the application of the related magnetic random memory device.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.