CN100576343C

CN100576343C - Antiferromagneticallstabilized stabilized pseudo spin valve for memory applications

Info

Publication number: CN100576343C
Application number: CN03802470A
Authority: CN
Inventors: 罗姆尼·R·凯蒂; 乔尔·A·德鲁斯; 托莫斯·J·沃格特
Original assignee: Micron Technology Inc
Current assignee: Micron Technology Inc
Priority date: 2002-02-06
Filing date: 2003-02-04
Publication date: 2009-12-30
Anticipated expiration: 2023-02-04
Also published as: CN1777958A

Abstract

The present invention relates to improve the stability of the magnetic memory cell in the MAGNETIC RANDOM ACCESS MEMORY (MRAM).Embodiments of the invention are increased to magnetic memory cell with inverse ferric magnetosphere.Inverse ferric magnetosphere can adjacently with the soft formation among the MRAM form on the side relative with hard formation MRAM soft formation.An embodiment also is included in the interbed of the other non-antiferromagnet between inverse ferric magnetosphere and the soft formation.

Description

Antiferromagneticallstabilized stabilized pseudo spin valve for memory applications

Technical field

The present invention relates in general to memory technology.Particularly, the present invention relates to non-volatile magnetic memory.

Background technology

Computing machine and other digital display circuit utilize storer with stored programme and data.Usually the storer of form is a random-access memory (ram).Many storage arrangements such as dynamic RAM (DRAM) device and static RAM (SRAM) device are volatile memory.Volatile memory loses its data when electric power is removed.For example, when traditional personal computer powered-down, volatile memory reloads by start-up course.Even in addition when continuous supply power, also need the regular update cycle such as certain volatile memory of DRAM device, to keep its data.

Opposite with the potential loss of data that runs in the volatile memory devices, non-volatile memory device can keep data for a long time when power-off.The example of non-volatile memory device comprises ROM (read-only memory) (ROM), programmable read-only memory (prom), can wipe PROM (EPROM), electric erasable PROM (EEPROM), flash memory etc.The shortcoming of traditional nonvolatile memory is relatively large, slower and expensive.In addition, traditional nonvolatile memory is limited to write cycle capability relatively and only can be programmed usually with at specific memory device location stored data about 10,000 times.This has hindered the traditional non-volatile memory device such as flash memory device to be used as general purpose storer.

Known optional memory device is changed to magnetoresistive RAM (MRAM).The MRAM device utilizes magnetic orientation to keep data in its memory cell.The advantage of MRAM be very fast relatively, be non-volatile, consume electricity relatively seldom and do not have the restriction of write cycle time.Pseudo-spin valve (PSV) MRAM device has utilized the asymmetric layer structure of ferromagnetic layer and metal level as memory cell.And ferromagnetic layer does not switch simultaneously.

The asymmetric layer structure of PSV MRAM comprises " hard formation " of storing data and switches or " soft formation " of triggering to allow data to store and read at hard formation.When operating as required, soft

Layer switched before hard formation.Advantage is the switching that soft formation switching has early suppressed hard formation, and then, this has caused the write threshold value of higher of PSV MRAM than spin valve MRAM.

The magnetization that a problem of traditional PSV MRAM device is a soft formation is not controlled preferably.Can not can cause PSV MRAM device to show as spin valve undesirably at the soft formation that switch in the low relatively magnetic field that applies, rather than PSV.This has reduced the data of writing threshold value and can cause damaging storage during write operation.In order to prevent the corrupted data of PSV MRAM device, it is a little to low level that the field that produces during write operation keeps, and this has caused the repeatability and the recyclability of relatively low read-write to memory cell.

Summary of the invention

Embodiments of the present invention address these and other problems by the trigger layer of stabilized pseudo spin valve (PSV).Embodiments of the invention comprise antiferromagnetic material (AFM) layer, and the antiferromagnetic material layer is stablized the magnetization of this thin layer.The stabilization of the trigger layer of PSV offers PSV MRAM good relatively repeatability and recyclability.

Embodiments of the present invention are included in the antiferromagnet in the magnetic memory cell.Antiferromagnetic layer can form at the trigger layer among the contiguous MRAM in the side of the trigger layer opposite with the accumulation layer of MRAM.A kind of layout also comprises the interbed (interlayer) of other antiferromagnetic layer and the non-antiferromagnetic material between the trigger layer.

Antiferromagnetic material (AFM) are adjacent or form near the trigger layer of PSV.The AFM layer should be formed on the side of trigger layer with the side thereof opposite with PSV accumulation layer.In addition, the quantity of the coupling between trigger layer and the AFM layer should be fully low, switches in the magnetic field lower than accumulation layer to allow trigger layer, thus in the magnetic field intensity that is used for read operation be used for keeping wide relatively zone between the magnetic field intensity of write operation.

One embodiment of the present invention are included in the pseudo-spin valve of antiferromagneticallstabilized stabilized in the MAGNETIC RANDOM ACCESS MEMORY.The pseudo-spin valve of antiferromagneticallstabilized stabilized comprise accumulation layer, the ferromagnetic material of ferromagnetic material trigger layer, be arranged on the nonferromagnetic material between accumulation layer and the trigger layer wall and with the antiferromagnetic layer of the adjacent setting of trigger layer.Antiferromagnetic layer also should be arranged on the side opposite with accumulation layer of trigger layer.Antiferromagnetic layer can be formed by manganese alloy, such as ferromanganese.

Another embodiment of the invention is included in the pseudo-spin valve of antiferromagneticallstabilized stabilized in the MAGNETIC RANDOM ACCESS MEMORY with AFM interbed.The pseudo-spin valve of antiferromagneticallstabilized stabilized comprises the accumulation layer that is suitable for the ferromagnetic material of magnetic orientation storage data, be suitable for switching directed with the trigger layer, the wall that is arranged on the nonferromagnetic material between accumulation layer and the trigger layer that allow the ferromagnetic material that data read from accumulation layer, be arranged on trigger layer the side opposite with accumulation layer on antiferromagnetic layer and the interbed that is used for inverse ferric magnetosphere, its middle layer reduces the magnetic couplings intensity between inverse ferric magnetosphere and accumulation layer and the trigger layer.The interbed that is used for inverse ferric magnetosphere can be formed by various materials, but should not formed by antiferromagnet.The suitable material that is used for interbed comprises iridium, copper, ruthenium, chromium and aluminium.The interbed that is used for inverse ferric magnetosphere can be thinner relatively, and for example thickness is unimolecular layer (monolayer) thickness.

Another embodiment of the invention comprises the method for stabilized pseudo spin valve.This method comprises that providing the magnetic resistance that comprises trigger layer and accumulation layer sandwich construction, wherein said trigger layer to be suitable for switching orientation reads from accumulation layer to allow data, and wherein said accumulation layer is suitable for magnetic orientation storage data; Form inverse ferric magnetosphere near the magnetic resistance sandwich construction on trigger layer and the side opposite with accumulation layer at trigger layer, wherein said inverse ferric magnetosphere is stablized the magnetization of trigger layer; And the interbed that is formed for inverse ferric magnetosphere, wherein said interbed is formed between inverse ferric magnetosphere and the trigger layer, and interbed reduces the magnetic couplings intensity between inverse ferric magnetosphere and accumulation layer and the trigger layer.

Description of drawings

With reference to following accompanying drawing these and other feature of the present invention is described below.These accompanying drawings are used to describe the preferred embodiments of the present invention with relevant explanation and do not limit the scope of the invention.

Fig. 1 is a skeleton view of describing giant magnetoresistance (GMR) unit of spin valve pattern.

Fig. 2 is a top-down schematic views of describing the GMR cell array.

Fig. 3 has described the GMR unit of pseudo-spin valve (PSV) pattern.

Fig. 4 is the sectional view according to the magnetoresistive stack of the pseudo-spin valve (ASPSV) that is used for antiferromagneticallstabilized stabilized of the embodiment of the invention.

Fig. 5 is the sectional view that is used for the magnetoresistive stack of ASPSV in accordance with another embodiment of the present invention.

Fig. 6 is the R-H figure of ASPSV that describes the threshold value of the write data when not selecting ASPSV.

Fig. 7 is the R-H figure that is used for the ASPSV of write operation, and wherein ASPSV stands the existence of digital field.

Fig. 8 is that the R-H of ASPSV that describes the threshold value of the write data when selecting ASPSV schemes.

Fig. 9 is the R-H figure of ASPSV that describes the threshold value of the read data when not selecting ASPSV.

Figure 10 is that the R-H of ASPSV that describes the threshold value of the read data when selecting ASPSV schemes.

Embodiment

Although will describe the present invention with certain preferred embodiment, be conspicuous other embodiment for those of ordinary skills, comprise the whole advantages that propose and the embodiment of feature are not provided here, also within the scope of the invention.Therefore, scope of the present invention only limits with reference to claim.

Magnetoresistive RAM (MRAM) is stored data under the magnetic state of its storage unit.The resistance of unit changes with the stored magnetic state of unit.The store status of unit is detected by the difference that detects resistance.

Fig. 1 is a skeleton view of describing the GMR unit 100 of spin valve pattern.GMR unit 100 comprises word line 102 and bit line 104.In the GMR unit, bit line 104 is also referred to as sense wire (sense line).Bit line 104 comprises magnetosphere.Data are by applying in the cell cube part that electric current is stored in bit line 104 by word line 102 and bit line 104 simultaneously.The polarization of the magnetic orientation of the logic state of the definite storage of the sense of current in word line 102 and the bit line 104 (with after-applied magnetic field) data.For example, the field component that is applied by bit line current can be the counter clockwise direction around bit line 104 that is used for the clockwise direction that centers on bit line 104 of first direction of current and is used for second direction of current, and word line 102 similarly.The vector in the magnetic field that two (or a plurality of) leads apply and the magnetic state of determining unit.

For from GMR unit 100 read datas, electric current is applied on the word line 102 and bit line 104 corresponding to GMR unit 100 once more.The resistance that electric current ran into that is applied on the bit line 104 changes with the logic state that is stored in the magnetosphere.Compare unit with unit and showed big voltage drop with this electric current with big resistance with less resistive.

Fig. 2 is a top-down synoptic diagram of describing GMR cell array 200.A plurality of unit are arranged to array 200 in storage arrangement.Cellular array 200 comprises a plurality of word lines 202 and a plurality of bit line 204.Individual unit in array 200 is selected by applying electric current through corresponding word line and corresponding bit line.Electric current only flows through the word line of unit or one unit in the bit line is not stored or sense data.

Fig. 3 has described the GMR unit 300 of pseudo-spin valve (PSV) pattern.GMR unit 300 comprises word line 302 and bit line 304.The bit line 304 of GMR unit 300 also is called sense wire and comprises the GMR storehouse, and the GMR storehouse comprises first magnetosphere 306, conductive layer 308 and second magnetosphere 310.First magnetosphere 306 and second magnetosphere 310 are by mismatch (mismatch), so that first magnetosphere 306 to the second magnetospheres, 310 magnetic " soft ".The mismatch of magnetic characteristic can followingly obtain: compare relative thinner by making first magnetosphere 306 with second magnetosphere 310; By selecting soft relatively magnetic material to be used for first magnetosphere 306 and selecting hard relatively magnetic material to be used for second magnetosphere 310; Or both.Other term that is used for description " hard formation " comprises " pinned layer (pinned layer) " and " fixed bed (fixedlayer) ".Yet the storage magnetic orientation that those of ordinary skill in the art will understand in the hard formation can change according to the logic state of storage data.Other term that is used for description " soft formation " comprises " variable layer " and " trigger layer (flipped layer) ".Those of ordinary skill in the art will understand the GMR storehouse can also comprise multilayer ferromagnetic material and wall.

GMR unit 300 is stored data as the magnetic orientation in second magnetosphere 310.Need higher relatively magnetic field to switch the magnetization of second magnetosphere 310, so that magnetization is maintained fixed in operation.The magnetic state of GMR unit 300 is switched by the magnetization of switching first magnetosphere 306, and the magnetization of first magnetosphere 306 can be by switching by the relatively low magnetic field that applies electrical current to corresponding word line 302 and 304 generations of corresponding bit line.The magnetization of the formation of first magnetosphere 306 or be either parallel or anti-parallel to the magnetization of second magnetosphere 310.When the magnetization in first magnetosphere 306 was parallel with the magnetization of second magnetosphere 310, the resistance of GMR unit 300 was lower than the resistance when the relative antiparallel of magnetization.Electric current in word line 302 and/or the bit line 304 can switch along both direction, correspondingly to switch first magnetosphere 306, the i.e. magnetization of soft magnetosphere between parallel and antiparallel state.Detect the resistance difference of bit line 304 then, allow the logic state of the GMR unit 300 of storage to be retrieved thus.

Fig. 4 shows the sectional view according to the magnetoresistive stack 400 of the PSV unit that is used for antiferromagneticallstabilized stabilized of the embodiment of the invention.The test findings that is used for magnetoresistive stack 400 will be described in conjunction with Fig. 6 to 10.Although magnetoresistive stack 400 is described as having restraining barrier or protective seam and has extra interbed, those having ordinary skill in the art will appreciate that the mode that embodiments of the invention comprise does not have all layer described herein.For example, the restraining barrier can be according to the component selections that becomes of the manufacturing process of using and substrate assembly, insulation course, conductor and magnetoresistance material self.

Illustrated magnetoresistive stack 400 comprises bottom 402, hard formation 404, first interbed 406, wall 408, second interbed 410, soft formation 412, antiferromagnetic (AFM) layer 414, first protective seam (caplayer) 416 and second protective seam 418.Bottom 402 or broadcast sowing layer (seeding layer) and provide lower floor in the substrate and the bounding force between the hard formation 404 by offering storehouse crystal structure (texture).Bottom 402 can also prevent atom diffusion from hard formation 404 to lower floor, for example silicon substrate.Various materials can be used in bottom 402.In one embodiment, bottom 402 is formed by tantalum (Ta).Can comprise titanium (Ti), ruthenium (Ru), ferronickel chromium (NiFeCr) and tantalum nitride (TaN) as other material of bottom 402.Bottom 402 can be formed into the thickness range of broad.In one embodiment, bottom 402 is at about 10 dusts

To about 100 In the thick scope.Various treatment technologies can be used to form various layer described herein, for example, and physical vapor deposition (PVD) technology, chemical vapor deposition (CVD) technology etc.

Hard formation 404 (or thick-layer) storage is used for the data of the PSV unit of antiferromagneticallstabilized stabilized.Relatively large word current produces the magnetic moment orientation of storage in relatively large magnetic field and the switching hard formation 404 with the storage data.Hard formation 404 can be made by various ferromagnetic materials, for example permalloy (Ni ₈₀Fe ₂₀), cobalt-iron (Co ₉₀Fe ₁₀) etc.In one embodiment, hard formation 404 is about 20

To about 100

In the thick scope.

First interbed 406 is selectable.First interbed 406 can be included in the magnetoresistive stack 400 to strengthen the signal from magnetoresistive stack 400, i.e. impedance variation.In one embodiment, hard formation 404 is formed by permalloy, and first interbed 406 is formed or formed by the alloy that comprises cobalt by cobalt (Co), for example Co ₉₀Fe ₁₀, Co ₈₀Fe ₂₀Deng.In an example, the thickness of first interbed 406 is about 2

To about 15

Scope in.

Wall 408 is non-magnetospheres of separating magnetosphere.Wall 408 can be formed by the various nonferromagnetic materials of wide range.The various materials of wide range can be used to form wall 408.In one embodiment, wall 408 is copper (Cu).Aldary also is suitable material, for example copper silver (CuAg) alloy, copper gold and silver (CuAuAg) alloy etc.In an example, the thickness of wall 408 is about 18

To about 45

Scope in.

Second interbed 410 is selectable.Second interbed 410 can be included to strengthen the signal from magnetoresistive stack 400.In one embodiment, soft formation 412 is formed by permalloy, and second interbed 410 is formed or formed by the alloy that comprises cobalt by cobalt (Co), for example Co ₉₀Fe ₁₀, Co ₈₀Fe ₂₀Deng.The thickness of second interbed 410 can be about 2

To about 15

Scope.

The magnetic moment of soft formation 412 (or thin layer) can switch or triggering with relative low magnetic field with low relatively word current.When the magnetic moment of soft formation 412 was parallel with the magnetic moment of hard formation 404, the impedance of PSV unit was relatively low.When the magnetic moment antiparallel (anti-parallel) of the magnetic moment of soft formation 412 and hard formation 404, the impedance phase of PSV unit is to higher.Soft formation 412 can be formed by various materials, for example permalloy (Ni ₈₀Fe ₂₀), cobalt-iron (Co ₉₀Fe ₁₀) alloy etc.In one embodiment, the thickness of soft formation 412 is than the thin thickness of hard formation 404 about 20% to about 80%.

AFM layer 414 is antiferromagnet layers.Antiferromagnet produces the electron spin of arranged anti-parallel and does not have Net magnetic moment in response to the magnetic field that applies.AFM layer 414 helps to control the magnetization of soft formation 412, so that soft formation 412 more as one man switches magnetic moment with the relatively low magnetic field that applies, allow antiferromagneticallstabilized stabilized PSV MRAM to keep comparatively safe and stable height to write threshold value thus, promptly improve the switching stability of this thin layer, AFM layer 414 is parallel with soft formation 412 on electricity.This can disturb from being used for the detection of detection of stored at the variableimpedance of the soft formation 412 of the memory state of hard formation 404.In order to reduce the interference that memory state is detected, AFM layer 414 should be formed and/or should be thinner relatively by the material with relative high resistivity.

AFM layer 414 is preferably formed by manganese alloy, for example comprises Fe ₅₀Mn ₅₀The antiferromagnetic alloy of ferrimanganic (FeMn).Other suitable manganese alloy comprises iridium manganese (Ir ₂₀Mn ₈₀), platinum manganese (PtMn) and nickel manganese (Ni ₄₅Mn ₅₅).AFM layer 414 can also ferromagnetic materials formation such as oxide, for example nickel oxide (NiO) and cobalt nickel oxide (NiCoO), but this oxide can be for temperature instability relatively.On the side relative that AFM layer 414 should be arranged on soft formation 412 with hard formation 404.In addition, AFM layer 414 should not reach the thickness that produces the soft formation spin, and the thickness of soft formation spin causes the vacuum-tube characteristic that spins by puppet spin vacuum tube unfriendly.In one embodiment, the thickness of AFM layer 414 is about 10

To about 70

Scope in.The thickness of AFM layer 414 can change according to the thickness and the switching field of hard formation 404 and soft formation 412.

First protective seam 416 offers AFM layer 414 adhesion and provides prevention to be diffused into the restraining barrier of other layer the substrate assembly undesirably from the atom of AFM layer 414.In one embodiment, first protective seam 416 is formed by tantalum (Ta).Other material that can be used for first protective seam 416 comprises copper (Cu), tantalum nitride (TaN) etc.The thickness of first protective seam 416 can be in the range of broad.In one embodiment, the thickness of first protective seam 416 is about 50 To about 500

In the thick scope.

Second protective seam 418 (or diffusion impervious layer protective seam) is selectable.For some etch processes, second protective seam 418 of increase provides good relatively restraining barrier.In one embodiment, second protective seam 418 is silicochromium (CrSi).Other material that can be used for second protective seam 418 comprises copper (Cu), tantalum (Ta), titanium nitride (TiN) etc.In one embodiment, the thickness of second protective seam 418 is about 100

To about 200

In the thick scope, but it should be appreciated by those skilled in the art that this thickness can change in the scope of broad.

Fig. 5 shows the sectional view of the magnetoresistive stack 500 that is used for the pseudo-spin valve of antiferromagneticallstabilized stabilized in accordance with another embodiment of the present invention.Magnetoresistive stack 500 comprises bottom 402, hard formation 404, first interbed 406, wall 408, second interbed 410, soft formation 412, first protective seam 416 and second protective seam 418, and above-mentioned layer is described in conjunction with Fig. 4.In addition, magnetoresistive stack 500 comprises AFM interbed 502 and the AFM layer 504 that is arranged between the soft formation 412 and first protective seam 416.Different with AFM layer 504, AFM interbed 502 is not formed by antiferromagnet.In one embodiment, AFM interbed 502 is formed by relatively thin iridium layer (Ir).Other the suitable material that is used for AFM interbed 502 comprises copper (Cu), ruthenium (Ru), chromium (Cr), aluminium (Al) etc.

AFM layer 504 is formed by antiferromagnet, for example manganeisen (FeMn).Other material that is suitable for AFM layer 504 comprises various other manganese alloy and various oxides, as described in conjunction with Fig. 4.On the side relative that AFM layer 504 should be arranged on soft formation 412 with hard formation 404.In one embodiment, the thickness of AFM layer 504 is about 70

To about 200 Scope in.The thickness increase of AFM layer 504 (with respect to AFM layer 414) has increased exchange coupling, so that the ferromagnetic thin film on the another side of AFM interbed 502 is affected.

AFM interbed 502 is arranged between AFM layer 504 and the soft formation 412.In an example, the thickness of AFM interbed 502 is about 1

To about 5

Scope in.Optimal way is the about unimolecular layer of the thickness of AFM interbed 502, a promptly about atomic layer level thickness.In one embodiment, the thickness of AFM interbed 502 is less than unimolecular layer.AFM interbed 502 is used for the wall between AFM layer 504 and the soft formation 412.

Advantageously, AFM interbed 502 can be used for by the coupling amount between the adjusting of the stiffness of coupling between reduction AFM layer 504 and hard formation 404 and/or the soft formation 412 or selection AFM layer 504 and the soft formation 412.Yet the thickness of AFM interbed 502 should not reach the thickness that causes the coupling between AFM layer 504 and the soft formation 412 to lose.More advantageously, AFM interbed 502 can also strengthen the consistance of the coupling between AFM interbed 502 and the soft formation 412.

Fig. 6-the 10th, the R-H Test Drawing of the example of the pseudo-spin valve of describing in conjunction with Fig. 4 of antiferromagneticallstabilized stabilized (ASPSV) above.It should be appreciated by those skilled in the art that this test result general changes according to the selection of material, bed thickness and cell geometry in fact.In Fig. 6-10, Z-axis, promptly the y axle is ohm corresponding to impedance and unit, shown in Fig. 6-10 right side.The number percent that the left side of Fig. 6-10, impedance also are expressed as based on the minimum impedance shown in each figure changes.Transverse axis, promptly the x axle represents that magnetic field intensity and unit are oersted (Oe).

Fig. 6 is the R-H figure that the example from the top magnetoresistive stack of describing in conjunction with Fig. 4 400 obtains.The R-H of Fig. 6 illustrates magnetoresistive stack 400 with respect to the impedance of first magnetic field of an axle that skims over (swept) magnetoresistive stack 400 (H field).A H field that applies is represented along level or the x axle of Fig. 6.Do not have other H field to be applied on the magnetoresistive stack 400, so the data representation among Fig. 6 is not selected the situation that will run in magnetoresistive stack 400 operation when corresponding ASPSV unit.Add the data that black data line correspondence is obtained with a H field of skimming over along a direction that is called forward; Thin data line correspondence is with obtaining the data of getting along being called the H field that reverse relative direction skims over.

As shown in Figure 6, advantageously, magnetoresistive stack 400 is not switched, and the numerical value up to a H field has reached higher relatively about 75-80Oe.This shows that nonoptional ASPSV unit can bear relative higher H field, and does not lose data.

Fig. 7 is the R-H figure of the example of the top magnetoresistive stack of describing in conjunction with Fig. 4 and 6 400.The R-H figure of Fig. 7 shows the impedance of magnetoresistive stack 400 with respect to a H field once more.Yet approximately the 2nd H field perpendicular to a H field also is applied on the magnetoresistive stack 400, is used for the data shown in Fig. 7.The 2nd H field is similar to the electric current of the conductor that flows through the ASPSV unit that is used for from the ASPSV array of MRAM selecting having magnetoresistive stack 400 with the H field that produces.The 2nd H field refers to " numeral " field sometimes in the art.

Level or x axle represent to skim over a H field of an axle of magnetoresistive stack 400.When magnetoresistive stack 400 was subjected to the 2nd H field, magnetoresistive stack 400 was switched when the about 53Oe of numerical value of a H field, so that write.This numerical value is lower than the about 75-80Oe that describes in conjunction with Fig. 6, and expression has been for having selected writing of ASPSV unit to take place, and the content of the nonoptional ASPSV of the rewriting that can not take place not expect unit.

Fig. 8 is the R-H figure of the example of the top magnetoresistive stack of describing in conjunction with Fig. 4,6 and 7 400.The R-H of Fig. 8 illustrates the impedance of magnetoresistive stack 400 with respect to a H field.Yet magnetoresistive stack 400 also is exposed to another H field, is called the 3rd H field.The 3rd H field produces by electric current being flow through be used to the selection wire of selecting corresponding to the ASPSV unit of magnetoresistive stack 400, for example word line or bit line.This allows in the ASPSV cell array of single ASPSV unit from MRAM selected.Because electric current flows through selection wire, magnetoresistive stack 400 is switched when the about 50Oe of numerical value of a H field, so that write.Thereby Fig. 6 and 8 shows magnetoresistive stack 400 when can storing data so that only approximately the H field strength of 50Oe is selected, and still keeps data when arriving up to a H field when about 75-80Oe does not select, and is provided for the interval of safe write data thus.

Fig. 9 is the R-H figure of the example of the top magnetoresistive stack of describing in conjunction with Fig. 4,6,7 and 8 400.The R-H of Fig. 9 illustrates magnetoresistive stack 400 with respect to the impedance of the H field of skim over a magnetoresistive stack axle of 400.In Fig. 9, there is not other H field to be applied on the magnetoresistive stack 400, therefore the data representation of being drawn among Fig. 9 allows the H Flow Field Numerical of reading from magnetoresistive stack 400 when magnetoresistive stack 400 does not have selectedly when promptly not standing the H field such as the active selection wire of bit line that just carries electric current or word line.In the example shown in Fig. 9, magnetoresistive stack 400 was born higher relatively about 70Oe numerical value before impedance unstability and variation H field.Do not expect in relatively low H field strength impedance variation, because there is not the selecteed ASPSV unit should impedance.The variation meeting of not expecting of impedance damages expectation or the reading of the impedance of the ASPSV unit selected nocuously.

Figure 10 is the R-H figure of the example of the top magnetoresistive stack of describing in conjunction with Fig. 4,6,7,8 and 9 400.The R-H of Figure 10 illustrates magnetoresistive stack 400 with respect to the impedance of the H field of skim over a magnetoresistive stack axle of 400.Also be applied on the magnetoresistive stack 400 by in word line or sense wire, carrying another H field that produces such as the electric current selection wire of word current or digit current respectively.Clearly, the ratio of the x axle of the R-H figure of Figure 10 is different with the R-H figure that describes in conjunction with Fig. 6,7,8 and 9.

The magnetic orientation of the soft formation 412 of magnetoresistive stack 400 switches or triggers along both direction, and the difference of impedance inquired, to read the numerical value that is stored in the data in the magnetoresistive stack 400.The soft formation 412 that R-H among Figure 10 illustrates magnetoresistive stack 400 can switch or triggers to read in the low H field strength of favourable about 35Oe.Magnetoresistive stack 400 when selected and do not have the H field between the magnetoresistive stack 400 when selected to read at interval approximately 35Oe.This advantageously allows corresponding M RAM to use the H field strength of relative wide region, reading from individual unit, and the not danger of lost data during reading.

Various embodiment of the present invention has been described above.Although described the present invention with reference to these specific embodiments, this explanation is intended to illustrate the present invention rather than restriction the present invention.Under the situation of the spirit and scope of the present invention that do not depart from claim and limited, those skilled in the art can expect various modifications and application.

Claims

1. the pseudo-spin valve of the antiferromagneticallstabilized stabilized in the MAGNETIC RANDOM ACCESS MEMORY comprises:

Accumulation layer ferromagnetic material, that be suitable for storing data with magnetic orientation;

Ferromagnetic material, be suitable for switching directed trigger layer to allow data to read from accumulation layer;

Be arranged on the wall of the nonferromagnetic material between accumulation layer and the trigger layer;

Be arranged on the inverse ferric magnetosphere on the side opposite with accumulation layer of trigger layer, wherein the magnetization of the trigger layer of ferromagnetic material is stable by described inverse ferric magnetosphere; And

Be arranged on the interbed that is used for inverse ferric magnetosphere between trigger layer and the inverse ferric magnetosphere, its middle layer is formed by non-antiferromagnet, and described interbed reduces the magnetic couplings intensity between described inverse ferric magnetosphere and described accumulation layer and the described trigger layer.

2. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, the thickness that wherein is used for the interbed of inverse ferric magnetosphere is

Extremely

3. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, the thickness that wherein is used for the interbed of inverse ferric magnetosphere is unimolecular layer thickness.

4. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, the thickness of interbed that wherein is used for inverse ferric magnetosphere is less than unimolecular layer thickness.

5. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, wherein inverse ferric magnetosphere is formed by manganese alloy.

6. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, wherein inverse ferric magnetosphere is formed by in nickel oxide and the cobalt nickel oxide at least one.

7. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, its middle layer is formed by iridium.

8. the pseudo-spin valve of antiferromagneticallstabilized stabilized according to claim 1, its middle layer is formed by in copper, ruthenium, chromium and the aluminium at least one.

9. the method for a stabilized pseudo spin valve comprises:

The magnetic resistance that comprises trigger layer and accumulation layer sandwich construction is provided, and wherein said trigger layer is suitable for switching directed to allow data to read from accumulation layer, and wherein said accumulation layer is suitable for magnetic orientation storage data;

Forming inverse ferric magnetosphere near trigger layer and the side opposite with accumulation layer at trigger layer on the magnetic resistance sandwich construction, wherein said inverse ferric magnetosphere is stablized the magnetization of trigger layer; And

Be formed for the interbed of inverse ferric magnetosphere, wherein said interbed is formed between inverse ferric magnetosphere and the trigger layer, and described interbed reduces the magnetic couplings intensity between described inverse ferric magnetosphere and described accumulation layer and the described trigger layer.

10. method according to claim 9, wherein inverse ferric magnetosphere is formed by manganese alloy, and interbed is formed by iridium.