CN1855531A - Conduction control device - Google Patents

Conduction control device Download PDF

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Publication number
CN1855531A
CN1855531A CNA2006100661743A CN200610066174A CN1855531A CN 1855531 A CN1855531 A CN 1855531A CN A2006100661743 A CNA2006100661743 A CN A2006100661743A CN 200610066174 A CN200610066174 A CN 200610066174A CN 1855531 A CN1855531 A CN 1855531A
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ferromagnetic
tie
ferromagnetic region
layer
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CN100459149C (en
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耶尔格·冯德里西
伊藤显知
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Hitachi Ltd
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Hitachi Ltd
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices

Abstract

A conduction control device comprises a first ferromagnetic region having relatively high coercivity, a second ferromagnetic region having relatively low coercivity and a junction region disposed between the first and second ferromagnetic regions. The device also comprises a gate for applying a field to the junction region so as to control charge carrier density within the junction region.

Description

Conduction control device
Technical field
The present invention relates to a kind of conduction control device.
Background technology
The novel electronic device occurs, and carrier transport is spinned by electric charge carrier at least in part and controls in these novel electron devices.Foremost example comprises Spin Valve and MTJ (MTJ) device based on giant magnetoresistance effect (GMR) in these what is called " from copper plate " device.Usually, these devices comprise the alternation of bed of ferromagnetism and nonferromugnetic material, and described nonferromugnetic material is (under the situation of MTJ device) of metallic (under the situation of Spin Valve) or insulation.Have several application from the copper plate device, comprise magnetic field sensor and magnetic RAM (MRAM).S.A.Wolf etc. are at Science, and " the Spintronics:A Spin-basedElectronics Vision for the Future " that roll up in 294, the 1488 to 1495 pages (2001) provided based on the electronic device of spin and the review of application.
In early days in the copper plate device, ferrimagnet comprises metal usually, such as iron (Fe), cobalt (Co) or nickel (Ni) or its alloy.Yet, what some was more recent adopts ferromagnetic semiconductor from the copper plate device, such as gallium-manganese-arsenic thing (Ga, Mn) As, H.Ohno etc. are at Science, roll up among " the Making Nonmagnetic Semiconductors Ferromagnetic " in 281, the 951 to 956 pages (1998) and described this ferromagnetic semiconductor.
Device based on ferromagnetic semiconductor has shown strong magneto-resistance effect.
For example, PhysicAl Review Letters, volume 91, p216602 (2003) goes up among " the Very Large Magnetoresistance in LaterAl Ferromagnetic (Ga, Mn) AsWires with Nanoconstrictions " that is delivered by C.Ruster etc. and has described a kind of structure that presents tunnel magneto resistance (TMR).This structure is from forming the thick Ga of 19nm in Semi-insulating GaAs 0.976Mn 0.024The As layer is constructed, and laterally determines by etching, to form the island areas that is connected to the lead on each limit in the both sides by the narrow part that contracts.
PhysicAl Review Letters, volume 93, p117203 (2004) are gone up among " the Tunneling Anisotropic Magnetoresistance:A spin-vAlue like tunnelmagnetoresistance using a single magnetic layer " that is delivered by C.Gould etc. and have been described a kind of device that shows the class spin valve effect.This device comprises a column, and described column is by aluminum oxide (AlO x) titanium/gold (Ti/Au) Metal Contact on the tunnel barrier layer constitutes, described aluminum oxide tunnel barrier is placed on the thick Ga of 70nm that forms on Semi-insulating GaAs 0.94Mn 0.06On the As layer.Strong anisotropy hysteresis effect in this experimental device is attributable to by the caused tunnel anisotropic magnetoresistance (TAMR) that is coupled of the strong spin(-)orbit in single ferromagnetic layer.
Summary of the invention
The present invention manages to provide a kind of conduction control device, for example is used in memory and/or the logical circuit, perhaps as magnetic sensor.
According to a first aspect of the invention, a kind of conduction control device is provided, comprises: have first ferromagnetic region than high-coercivity, have low coercive force second ferromagnetic region, place between first and second ferromagnetic region, be used for magnetically making the tie region that first and second ferromagnetic region separates and be used for to tie region apply electric field with the control tie region in the grid of electric charge carrier concentration.
Thereby described grid can be used for exhausting or accumulate electric charge carrier in the tie region forming tunnel barrier layer or conductive channel, thereby the read and write state is provided respectively.
Described device can comprise: have the coercive force that is higher than second ferromagnetic region the 3rd ferromagnetic region, place another tie region between the second and the 3rd ferromagnetic region and be used for applying electric field to change another grid of electric charge carrier concentration in this tie region to another tie region.
Described device can comprise another grid, is used for applying electric field to second ferromagnetic region.This another grid can be used for increasing or reduce the electric charge carrier concentration in second ferromagnetic region, thereby changes its magnetic characteristic such as coercive force.
First and second ferromagnetic region can comprise identical materials, and it can be such as (Ga, Mn) ferromagnetic semiconductor of As and so on.Tie region also can comprise identical materials.Described first and second ferromagnetic region and tie region can form in a layer.
First ferromagnetic region can be extended, and has the longitudinal axis.This longitudinal axis can be positioned on the direction of easy magnetizing axis.
Described device can be configured to and presents tunnel anisotropic magnetoresistance (TAMR) effect and/or tunnel magneto resistance (TMR) effect.
Can by be configured in fact one in the plane one deck or the part of one deck second ferromagnetic region is provided.The thickness of the part of this layer or this layer is less than or equal to 10nm.Second ferromagnetic region have outside the plane of the part of this layer or this layer easy magnetizing axis and/or toward this layer or layer the plane of a part within easy magnetizing axis.Can be by being configured in this plane in fact or another part of another layer in another plane or this layer provides first ferromagnetic region.First ferromagnetic region has the easy magnetizing axis within the plane of the part of another layer or another layer.
According to a second aspect of the invention, a kind of device is provided, and it comprises: conductive region, ferromagnetic region, be used to connect the tie region of conductive region and ferromagnetic region and be used for applying electric field to control the grid of electric charge carrier concentration in this tie region to this tie region.
Described conductive region can comprise nonferromugnetic material or semi-conducting material or nonferromagnetic semi-conducting material.Tie region can comprise semi-conducting material.Conductive region, tie region and/or ferromagnetic region can comprise identical materials.
A kind of memory array of conduction control device is provided according to a second aspect of the invention.
According to a third aspect of the invention we, a kind of method of making conduction control device is provided, described method comprises: first ferromagnetic region that has than high-coercivity is provided, second ferromagnetic region with low coercive force is provided, provides to place between first and second ferromagnetic region, be used for tie region that first and second ferromagnetic region is separated; And be provided for applying electric field to control the grid of electric charge carrier concentration in the tie region to tie region.
Provide tie region to comprise the narrow part of determining between first and second tie region that contracts.
According to a forth aspect of the invention, a kind of method of operating channelled conduction control device is provided, and described conduction control device comprises: have first ferromagnetic region than high-coercivity, have low coercive force second ferromagnetic region, place between first and second ferromagnetic region, be used for the tie region of magnetically first and second ferromagnetic region being separated; And be used for applying electric field to control the grid of electric charge carrier concentration in the tie region to this tie region, described method comprises to grid and applies first bias voltage to increase the electric charge carrier concentration in the tie region, and driving first current impulse by this passage, described current impulse has first current amplitude greater than the critical value of the magnetic reversal of second ferromagnetic region.
This has following advantage, promptly need not the i.e. magnetization of optionally reverse second ferromagnetic region of magnetization of reverse first ferromagnetic region.
This method can comprise to described grid and applies second bias voltage reducing the electric charge carrier concentration in the tie region, and drives second current impulse by this passage, and described second current impulse has second current amplitude less than critical value.
According to a fifth aspect of the invention, a kind of method of operating channelled conduction control device is provided, and described device comprises: have first ferromagnetic region than high-coercivity, have low coercive force second ferromagnetic region, place between first and second ferromagnetic region, be used for the tie region of magnetically described first and second ferromagnetic region being separated; And be used for applying electric field to control the grid of electric charge carrier concentration in the tie region to described tie region, described method comprises to described first and second ferromagnetic region and applies the magnetization of magnetic field with reverse second ferromagnetic region, described magnetic field is greater than the critical magnetic field of second ferromagnetic region, but less than the critical magnetic field of first ferromagnetic region.
This has following advantage, promptly need not the i.e. magnetization of optionally reverse second ferromagnetic region of magnetization of reverse first ferromagnetic region.
By example, embodiments of the invention are described with reference to the accompanying drawings now, wherein:
From the following description of the embodiments of the invention that carry out with accompanying drawing, other purposes of the present invention, feature and advantage will become apparent.
Description of drawings
Fig. 1 is the perspective view according to conduction control device of the present invention;
Fig. 2 is the plane graph of device shown in Figure 1;
Fig. 3 is along line A-A ' and the cross section of the device shown in Figure 2 that obtains;
Fig. 4 is the magnetized schematic diagram of ferromagnetic region in the device shown in Figure 1;
Fig. 5 is the schematic representation of apparatus that is used to operate device shown in Figure 1;
Fig. 6 example has illustrated gate bias, current impulse and the magnetic field that can be applied to the device of Fig. 1 during write cycle time;
Fig. 7 example has illustrated the gate bias and the current impulse of the device that can put on Fig. 1 during the read cycle;
Fig. 8 A has shown the method for making device shown in Figure 1 to 8D;
Fig. 9 is the plane graph according to another conduction control device of the present invention;
Figure 10 is the cross section of the device shown in Figure 9 that obtains along line B-B ';
Figure 11 example has illustrated the device shown in Figure 1 as gate;
Figure 12 example has illustrated gate bias, current impulse and the magnetic field that can be applied to the device of Fig. 1 during write cycle time;
Figure 13 example has illustrated the gate bias and the current impulse of the device that can be applied to Fig. 1 during the read cycle;
Figure 14 is the truth table that is used for device shown in Figure 11;
Figure 15 is the schematic diagram according to memory cell of the present invention;
Figure 16 example has illustrated the part of the memory array that comprises memory cell shown in Figure 15;
Figure 17 A and 17B are the cross sections of the memory cell shown in Figure 15 obtained along line C-C ' and D-D ' respectively;
Figure 18 is the schematic diagram that comprises the memory array of drive circuit;
Figure 19 example has illustrated that the memory cell in memory array shown in Figure 180 writes; And
Figure 20 example has illustrated the memory cell that reads in the memory array shown in Figure 180.
Specific embodiment
Device architecture
With reference to figure 1,2 and 3, conduction control device 1 according to the present invention comprises conductive channel 2 and first, second and the 3rd grid 3,4,5 of extension.
Passage 2 comprises and has than first and second ferromagnetic region 6,7 of high-coercivity and the 3rd ferromagnetic region 8 with low coercive force.The 3rd ferromagnetic region 8 places between first and second ferromagnetic region 6,7 usually, makes that the conduction between first and second ferromagnetic region 6,7 takes place via the 3rd ferromagnetic region 8.Thereby first and second fixed area 6,7 are also as source electrode and drain region.
First, second is formed by identical ferrimagnet with the 3rd ferromagnetic region 6,7,8.Yet first, second can be formed by different ferrimagnets with the 3rd ferromagnetic region 6,7,8, such as ferromagnetic metal and ferromagnetic semiconductor.Thereby ferromagnetic semiconductor can comprise a kind of wherein doped magnetic impurity becomes ferromagnetic semiconductor, and the doping content of described magnetic impurity can change.In addition, ferromagnetic semiconductor other the nonmagnetic impurity that can mix.Alternatively, ferromagnetic semiconductor can comprise to mix and can present ferromagnetic semiconductor, and it can doped magnetic or nonmagnetic impurity.
Passage 2 comprises first and second tie region 9,10.On magnetic reversal can occur in meaning in the first and the 3rd zone 6,8 with different magnetic field, first tie region 9 is separately first ferromagnetic region 6 and the 3rd ferromagnetic region 8 magnetically.Similarly, second tie region 10 is magnetically separated second ferromagnetic region 7 and the 3rd ferromagnetic region 8.First and second tie region 9,10 comprise semi-conducting material.First and second tie region 9,10 can be formed by identical materials, and can be by forming with one or more ferromagnetic region 6,7,8 identical materials.
Ferromagnetic region and tie region 6,7,8,9,10 are arranged in the patterned ferromagnetic layer 11 that comprises ferromagnetic semiconductor, and described in this example ferromagnetic semiconductor is that to have manganese content x be 0.02 gallium-manganese-arsenic thing alloy (Ga 1-xMn xAs), in other words be Ga 0.98Mn 0.02As.Yet, also can adopt gallium-manganese-arsenic thing alloy with other manganese content, for example can use x=0.06.In addition, can use and use other ferromagnetic semiconductors, such as (In, Mn) As, (Ga, Mn) P, (Ga, Mn) N or Ge 1-yMn yIn this example, described patterned ferromagnetic layer 11 has the thickness of 10nm.Yet ferromagnetic layer 11 can be thinner, and for example 3nm or 5nm are perhaps thicker.
Utilize ferromagnetic semiconductor rather than ferromagnetic metal or alloy to have the following advantages, be that grid can be used for applying electric field changing the density and/or the distribution of electric charge carrier to ferrimagnet, described electric charge carrier is regulated magnetic order and is changed the magnetic characteristic of ferrimagnet.It also has following advantage, promptly because the critical current density that is used for ferromagnetic semiconductor spin-torque (spin-torque) magnetic reversal usually than low two to three orders of magnitude in the ferromagnetic metal, so reduced power consumption.
Patterned ferromagnetic layer 11 is positioned at above the insulating barrier 12 of a common expansion, and this insulator layer 12 comprises insulator, and described insulator is aluminum arsenide (AlAs) in this example.Can adopt other insulators.Insulator can be a crystal.Insulator can with the ferromagnetic semiconductor lattice match, or do not match with ferromagnetic semiconductor and to help to cause the stress of magnetic anisotropy with generation.Ferromagnetic layer 11 and insulating barrier 12 need not be common expansion.For example, insulating barrier 12 can be bigger.Insulating barrier 12 is positioned at above the partially-etched substrate 13, and described substrate comprises semi-insulating GaAs (GaAs) in this example.Can adopt other substrates, such as silicon.Cover layer 14 (removing in order to know to be shown as in Fig. 1 partly) common expansion ground is positioned on the patterned ferromagnetic layer 11.In this example, cover layer 14 comprises AlAs.Cover layer 14 and ferromagnetic layer 11 need not be common expansion.
With particular reference to Fig. 2 and 3, determine the 3rd ferromagnetic region 8 and first and second tie region 9,10 by the narrow part 15,16 that contracts.The narrow part 15,16 that contracts is determined the first side wall 17 and the second, first and second parts 18 of relative sidewall 18 1, 18 2Between.On plane graph, each sidewall sections 18 1, 18 2Inside recess towards the first side wall 17 is provided.Can utilize other side wall constructions, for example utilize the inflexion of other shapes and/or utilize a pair of relative inflexion, determine the narrow part 15,16 that contracts.The narrow part 15,16 that contracts can be extended, and is for example partly provided by a narrow conductive channel.
Can otherwise come to determine tie region 9,10 and not need to adopt the narrow part that contracts.For example, tie region 9,10 can comprise different materials or have the material of different levels of doping.
That first and second ferromagnetic region 6,7 are normally extended and have width W and length L, make W＜L.Width W can be less than or equal to 100nm and can be less than or equal to 50nm.In this example, W is 50nm and L is 200nm.
The 3rd ferromagnetic region 8 can be extend and have width w and a length l.Width w can be less than W.In this example, w is 40nm and l is 60nm.
The magnetic shape anisotropy can be used for the coercive force with respect to first and second ferromagnetic region 6,7, reduces the coercive force of the 3rd ferromagnetic region 8, if particularly ferromagnetic region 6,7,8 comprises identical materials.Thereby, by being arranged to have with other ferromagnetic region 6,7, the 3rd ferromagnetic region 8 compares different breadth length ratios, the 3rd ferromagnetic region 8 can be configured to have lower coercive force.Described breadth length ratio is defined as the ratio of width and length, i.e. w/l and W/L.Thereby the 3rd ferromagnetic region 8 can have the breadth length ratio higher than first and second ferromagnetic region 6,7.
Each narrow part 15,16 that contracts all has the width c less than w.The narrow partial width c that contracts can be less than 20nm.In this example, the narrow partial width c that contracts is 10nm.
The narrow part 15,16 that contracts can have different width.For example, the first narrow part 15 that contracts is enough narrow so that for device 1 provides a tunnel barrier layer presenting tunnel anisotropic magnetoresistance (TAMR), and the second narrow part 16 that contracts can broad, and it is enough wide so that tunnel barrier layer is not provided, or vice versa.Thereby, can determine the 3rd magnetic regions 8, but have only a narrow part 15,16 that contracts that tunnel barrier layer is provided.
First and second grids 3,4 are controlled electric charge carrier concentration in first and second tie region 9,10 respectively so that switch tie region 9,10 between conduction and state of insulation, preferably switch between ohmic state and tunnel effect state respectively.
In this example, first and second grids 3,4 normally are in the same plane and with tie region 9,10 with tie region 9,10 and laterally separate, and are configured to approach the first side wall 17 so that a kind of side gating structure is provided.Thereby first and second grids 3,4 pass the first side wall 17 with corresponding electric field 19,20 and are applied in first and second tie region 9,10.Yet, can adopt other gating structures.For example, each side grid 3,4 can comprise a pair of relative side grid, and it often is called as " branch grid ".Each grid 3,4 can comprise additionally or alternati and is positioned at the top grid above the tie region 9,10 and/or is positioned at bottom grid under the tie region 9,10.Can separate grid 3,4 and tie region 9,10 by the dielectric layer (not shown).
Difference devices spaced apart s between first and second grids 3,4 and first and second tie region 9,10 in described side gating structure.S can be less than 20nm, less than 10nm or less than 5nm at interval.In this example, s is 10nm at interval.
In top grid and/or side grid structure, the interval between grid 3,4 and the knot 9,10 can be determined that described intermediate insulation style is as comprising such as silicon dioxide (SiO by the thickness of intermediate insulation body (not shown) 2), silicon nitride (Si 3N 4) and so on the amorphous insulating material, or such as (Ga, Mn) the insulation crystalline material of AlAs of As and so on.The intermediate insulation body is preferably enough thick in to prevent at least tunnel effect or the puncture when the typical grid voltage.The thickness of insulator can be less than 20nm and can be less than 10nm.The thickness of insulator can be less than 6 or 5nm, but are higher than 2 or 3nm.
Can select at interval based on the amplitude of the breakdown electric field of the amplitude of applying electric field 19,20 and gap between grid 3,4 and knot 9,10 or isolated insulation body (not shown).
The 3rd grid 5 is set to thereby the side grid of the 3rd ferromagnetic region 8 is also changed coercive force with the charge carrier density of controlling in the 3rd ferromagnetic region 8.This can have following advantage, and promptly it can reduce required electric current of magnetic reversal and/or magnetic field, thereby reduces power consumption.It can also have following advantage, and promptly it can be used to increase or reduce the sensitiveness of device when device is used as magnetic field sensor.
The 3rd grid 5 is in the same plane and with the 3rd ferromagnetic region 8 with the 3rd ferromagnetic region 8 usually and laterally separates, and approaches second sidewall 18 and be provided with so that a kind of side gating structure is provided.Thereby the 3rd grid 5 passes second sidewall 18 with electric field 21 and is applied in the 3rd ferromagnetic region 8.Yet, can adopt other gating structures.For example, the 3rd grid 5 can comprise a pair of relative side grid.The 3rd grid 5 can comprise additionally or alternati and is positioned at the top grid on the free space 8 and/or is positioned at bottom grid under the 3rd ferromagnetic region 8.Top or bottom gate configuration can have following advantage, promptly can to electric field expose the 3rd ferromagnetic region 8 than large tracts of land or volume, thereby bigger control to the magnetic characteristic of ferromagnetic region 8 is provided, such as coercive force.The top grid structure is described after a while in more detail.
In side gating structure, separated s ' at interval between the 3rd grid 5 and the 3rd ferromagnetic region 8.S ' can be less than 20nm, less than 10nm or less than 5nm at interval.In this example, s ' is 10nm at interval.
In top grid and/or side grid structure, the interval between grid 5 and the 3rd ferromagnetic region 8 can be determined that described intermediate insulation style is as comprising insulating material amorphous or crystal, as mentioned above by the thickness of intermediate insulation body (not shown).The thick of insulator can be less than 20nm and can be less than 10nm.The thick of insulator can be less than 6 or 5nm, but are higher than 2 or 3nm.
Can select at interval based on the amplitude of the breakdown electric field of the amplitude of applying electric field 21 and gap between grid 5 and the 3rd ferromagnetic region 8 or spacer insulator (not shown).
Grid 3,4,5 is arranged in patterned ferromagnetic layer 11, and is positioned on insulating barrier 12 and the substrate 13, and is positioned under the cover layer 14.
Can adopt the nonferromagnetic zone to replace first ferromagnetic region 6, such as nonferromagnetic, semiconductor regions.Second ferromagnetic region 7 can be ignored, perhaps the nonferromagnetic zone can be adopted as an alternative.The device of comprise conductive region, ferromagnetic region, the tie region of be used for electrically being coupled conductive region and ferromagnetic region and being used to being controlled the grid of electric charge carrier concentration in the tie region can be used as magnetic sensor.The magnetization
In this example, first, second and the 3rd ferromagnetic region the 6,7, the 8th are by (Ga, Mn) As forms.(Ga, Mn) ferromagnetism among the As is as touring hole and the fixing exchange interaction between the Mn ion and occurring.Thereby the concentration that changes electric charge carrier can change the magnetic characteristic of device 1, even can suppress magnetic order.
Ferromagnetic region 6,7,8 can each comprise separately single magnetic domain.By with zone 6,7,8 sizes that are configured to have less than intended size, typically be about the order of magnitude of 1 to 10 μ m, zone 6,7,8 can be set to have single magnetic domain.
With reference to figure 4, shown first, second and the 3rd ferromagnetic region 6,7,8 and magnetized 22,23,24 schematic diagram accordingly.
First, second and the 3rd ferromagnetic region 6,7,8 are magnetized in the plane of layer 11, and have corresponding magnetization 22,23,24.Yet one or more ferromagnetic region 6,7,8 can be magnetized outside the plane of layer 11, for example perpendicular to the plane of layer 11.For example, first and second ferromagnetic region 6,7 can be magnetized in the plane of layer 11, and the 3rd ferromagnetic region 8 can be magnetized outside the plane of layer 11, and perhaps vice versa.
Last formed (the Ga of GaAs, Mn) the As film is compressed stress owing to lattice does not match, and under low temperature (in this case, about 4.2 ° of K are following), presenting the biaxial anisotropy, described biaxial anisotropy has along the easy magnetizing axis of [100] and [010] crystallization direction.Thereby, usually, every kind along [100], [010], the magnetization of [100] or [010] crystallization direction location all has identical anisotropy energy.
Yet, for example because shape or stress can be introduced further anisotropy, described shape or stress can cause that easy magnetizing axis moves and/or breaks 4 heavy degeneracys, thus make along an easy magnetizing axis to the energy aspect that is positioned at be preferable over another easy magnetizing axis.
The 3rd ferromagnetic region 8 is extended so that introduce shape anisotropy along the longitudinal axis 25.First and second ferromagnetic region 6,7 also can be extended along axle 25.In this example, locate the longitudinal axis 25 along [100] crystallization direction 26.Yet the longitudinal axis 25 also can be located along [010] crystallization direction 27.
Higher when approaching the temperature of Curie temperature (Curie temperature), GaAs last formed (Ga, As) Mn also presents uniaxial anisotropy, described uniaxial anisotropy has along the easy magnetizing axis of [110] crystallization direction.Thereby the longitudinal axis 25 also can be located along [110] crystallization direction 28.
Easy magnetizing axis can be configured to towards out-of-plane direction.Anisotropy outside the GaMnAs midplane can be by introducing tensile stress in the GaMnAs film, for example by growth GaMnAs film on InGaAs, or the hole concentration that goes up in the GaMnAs film of growing by reduction GaAs obtains.Thereby, by applying electric field to 5 pairs the 3rd ferromagnetic region 8 of use the 3rd grid, the 3rd ferromagnetic region 8 optionally presents towards out-of-plane magnetic anisotropy, the magnetic anisotropy that while first and second ferromagnetic region 6,7 still present in the plane.This can cause bigger TAMR effect.
If adopt different ferrimagnets, easy magnetizing axis may be different so.
In this example, easy magnetizing axis is in the plane of layer 11.When not applying external magnetic field or electric current, magnetization 22,23,24 is located along one of easy magnetizing axis 26,27.Yet if apply the external magnetic field with the direction that is different from the direction of magnetization, magnetizing 22,23,24 direction so can switch to another easy magnetizing axis 26,27 from an easy magnetizing axis 26,27.In addition, if apply enough strong electric current to influence spin-torque, magnetizing 24 direction so can switch to another easy magnetizing axis 26,27 from an easy magnetizing axis 26,27.
As shown in Figure 4, higher resistance states when aiming at one of easy magnetizing axis 26,27, takes place in magnetization 24.In this example, when magnetizing 24 along first easy magnetizing axis 26, promptly when crystallization direction exists, lower resistance states takes place then along [100], and promptly, then occur than higher resistance states when crystallization direction exists along [010] along second easy magnetizing axis 27 when magnetization 24.
In this example, the longitudinal axis 25 of device is aimed at [100] crystal axis 26.When the magnetization 24 of the 3rd ferromagnetic region 8 when being parallel to [100] direction location of electric current, device is in low resistance state.When the magnetization along perpendicular to [010] direction of electric current location the time, device 1 is in high resistance state.
Though device 1 can utilize the TAMR effect, it does not need to do like this.As an alternative, device 1 can utilize other effects, and such as tunneling magnetoresistance (TMR), wherein device resistance depends on the direction of the direction of magnetization 24 of the 3rd ferromagnetic region 8 with respect to the direction of magnetization 22,23 of first and second ferromagnetic region 6,7.
Even ferromagnetic region 6,7,8 is made up of identical materials, still can be for example by optionally shaping the 3rd ferromagnetic region 8 to have given geometry, in this example by less extension, and the 3rd ferromagnetic region 8 is configured to have lower coercive force.In addition or alternatively, the other technologies that reduce coercive force be can adopt, for example damage or their combination introduced in the free space 8 by making regional 8 attenuation by etching or being infused in by ion.
Because the 3rd ferromagnetic region 8 has the coercive force that is lower than first and second zones 6,7, so oppositely occurring in of its magnetization 24 is lower than the reverse critical magnetic field of the magnetization 22,23 of two ferromagnetic region 6,7 in addition.Thereby, can apply such magnetic field, described magnetic field is higher than the critical magnetic field of the 3rd ferromagnetic region 8, but is lower than the critical magnetic field of first and second ferromagnetic region 6,7.When applying this electric field of picture, the magnetization 24 that can switch the 3rd ferromagnetic region 8, the magnetization 22,23 of first and second ferromagnetic region 6,7 simultaneously keeps being oriented on the identical direction separately.Can utilize this behavior like this, during normal running, first and second ferromagnetic region 6,7 provide the zone with fixed-direction magnetization 22,23, and the 3rd ferromagnetic region 8 provides the zone with magnetization 24 that can reverse directions.Thereby each all can be described as " fixing " or " pegging " zone first and second ferromagnetic region 6,7, and the 3rd ferromagnetic region 8 can be thought " freedom " zone.For convenience's sake, first and second ferromagnetic region 6,7 are designated hereinafter simply as first and second fixed area 6,7, and the 3rd zone 8 is designated hereinafter simply as free space 8.
As mentioned above, if apply enough strong electric current, magnetizing 24 direction so can switch to another easy magnetizing axis 26,27 from an easy magnetizing axis 26,27.This may be that it will cause that described wall passes free space 8 because the spin-torque on the neticdomain wall moves.
The magnetization 22,23 of first and second fixed area 6,7 is positioned on the identical direction.This can realize by applying a magnetic field that is higher than the critical magnetic field of first and second fixed area 6,7.
With traditional comparing from the copper plate device, device 1 has several advantages.
For example, traditional take to comprise the form of the vertical stacking of complex multilayer usually from the copper plate device, wherein each layer has fixed function.Yet device 1 can be thought better simply structure, and wherein the different piece of device 1 has difference in functionality and can regulate.For example, tie region 9,10 can play tunnel barrier layer, provides domain wall to peg and/or forms the zone as the nucleus of domain wall.Can change the magnetic characteristic of the 3rd ferromagnetic region 8, such as magnetic anisotropy and coercive force.
Device work
With reference to figure 5, the device 29 that is used to operate conduction control device 1 comprises: be used for current source 30 and selectable resistors in series 31 that drive current I passes passage 2, be used for respectively applying first, second and the 3rd grid voltage V to first, second and the 3rd side grid 3,4,5 G1, V G2, V G3First, second and tertiary voltage source 32,33,34, be used to measure the voltage drop V between first and second fixed area 6,7 SDThereby, determine whether device 1 is in the potentiometer 35 of high or low resistive state.
Also can be provided for producing magnetic field B Ext Source 36.Source 36 can comprise the inductor (not shown), such as lead, loop or coil, and is used for the source electrode (not shown) that drive current passes inductor.The inductor (not shown) can place on the substrate 13 (Fig. 1) that approaches device 1 (Fig. 1).
Device 1 can be used for storing data and/or sensing magnetic field.
With reference now to Fig. 5 to 7 describe to device 1 write data and from device 1 flow process of read data.
Cooling device 1 is to the Curie temperature T of ferrimagnet cBelow.In this example, Ga 0.98Mn 0.02The about 48 ° of K of the Curie temperature of As, and device is cooled to 4.2 ° of K.Other ferrimagnets may have high Curie temperature, therefore can work in higher temperature based on the device of these materials.
With particular reference to Fig. 6, in writing flow process, first and second voltage sources 32,33 can each apply bias voltage 37,38, i.e. V to first and second grids 3,4 G1=V G2=-V 1, so that increase electric charge carrier concentration in the tie region 9,10, thereby the resistance that reduces tie region 9,10 is so that their conductions, preferably as ohmic conductor.Knot 9,10 enough conductions are to present the reversal of magnetism that electric current causes.
In this example, | V G1| and | V G2| be the order of magnitude of 1V.Yet these can obtain by normal experiment.
In that (Ga, Mn) among the As, it is that the hole is main that electric charge carrier transports.Thereby, back bias voltage is applied to first and second grids 3,4 to increase the electric charge carrier concentration in the tie region 9,10.Yet,, so positive bias is applied to grid 3,4 if use electric charge carrier wherein to transport to be electronics for main ferromagnetic semiconductor.
Tertiary voltage source 34 can apply bias voltage 39, i.e. V to the 3rd grid 5 G3=V 2Thereby, reduce the electric charge carrier concentration on the ferromagnetism island areas 8, thereby reduce coercive force.
In this example, | V G3| be the order of magnitude of 1V.Yet these can obtain by normal experiment.
Power supply 30 drives has amplitude I C Current impulse 40, i.e. I SD=I C, described amplitude I CThe critical current that is higher than ferromagnetism island areas 8.Current impulse or strengthen existing magnetization 24 (Fig. 4) or for example change 90 ° and will magnetize 24 reverse (Fig. 4) by magnetizing.Can obtain to magnetize 24 assigned direction by the polarity of selecting current impulse.Current impulse 40 has duration Δ t 1Duration Δ t 1May be less than or equal to 100ns, 10ns or 1ns.In this example, duration Δ t 1Be 100ps.
For ferromagnetic metal, typical critical current density is about 10 7Acm -2, and for ferromagnetic semiconductor, typical critical current concentration is about 104Acm -2Or 105Acm -2Yet, can obtain the amplitude and the minimum duration of the required current impulse of magnetic reversal 40 by normal experiment, for example by with the current density that increases gradually and/or shorter duration drive current and measuring resistance.
Magnetic field sources 36 can apply magnetic field pulse 41 with assist current pulse 40.Yet magnetic field sources 36 can apply permanent magnetic field with biasing free space 8.Thereby the current impulse 40 that has than low amplitude value can be used for magnetic reversal.Magnetic field sources 36 can be inductive source or permanent magnet.
With particular reference to Fig. 7, in reading flow process, first and second voltage sources 32,33 can each apply bias voltage 42,43, i.e. V to first and second grids 3,4 G1=V G2=V 3Thereby, exhaust the electric charge carrier in the tie region 9,10, preferably form tunnel barrier layer.Form at least one tunnel barrier layer and have such advantage, promptly device 1 can adopt the TAMR effect with high magneto-resistor.In this example, be that the hole is main because transport, so apply positive bias to reduce the electric charge carrier concentration in the tie region 9,10.
In this example, V 3The order of magnitude for 1V.Yet, can obtain exhausting the required bias voltage of electric charge carrier in the tie region 9,10 by normal experiment, for example by increasing gate bias and measuring source-drain characteristics.
Tertiary voltage source 34 or apply zero-bias 44, i.e. V to the 3rd grid 5 G3=0, perhaps allow the 3rd grid 5 float.
Current source 30 drives has amplitude I PMeasurement or probe current pulse 45, i.e. I SD=I P＜I C, its critical current than ferromagnetism island areas 8 is lower.Current impulse 40 has duration Δ t2.Direct impulse can be longer than write pulse, in other words Δ t 2＞Δ t 1Can be the approximately uniform duration, i.e. Δ t 2≈ Δ t 1Perhaps can be shorter than write pulse, i.e. Δ t 2＜Δ t 1Duration is depended on the RC value of device 1 and/or the sensitivity of potentiometer 36.Duration Δ t2 can be smaller or equal to 100ns, 10ns or 1ns.In this example, duration Δ t 2Be 1ns.
Can make I PAmplitude low as far as possible, still make simultaneously and can carry out voltage measurement.Can determine I by routine test PValue.
Pass device 1 along with driving probe current pulse 45, pass device 1 and the voltage drop that forms measured by potentiometer 35.
If device 1 is in high resistance state, will measure the big pulse 46 of falling so corresponding to high voltage HIf device 1 is in low resistance state, will measure so corresponding to low voltage fall than small-pulse effect 46L.
Device is made
With reference now to Fig. 8 A, the method for making device 1 is described to 8D.
With reference to figure 8A, the wafer of GaAs that uses semi-insulating (001) crystal orientation is as substrate 13 ', and is written into molecular beam epitaxy (MBE) system (not shown).
On substrate 13 ', form not doped with Al As layer 12 ' in a conventional manner by MBE.AlAs layer 12 ' thickness is 10nm.Yet AlAs layer 12 ' may be thinner, 5nm for example, perhaps it can be thicker, for example 20 and 50nm between.
Go up formation Ga by low temperature MBE at AlAs layer 12 ' 0.98Mn 0.02As layer 11 ', for example by R.Campion etc. at JournAl of CrystAl Growth, volume 247, p42 (1303) is described.Ga 0.98Mn 0.02As layer 11 ' thickness is 10nm.Yet, Ga 0.98Mn 0.02As layer 11 ' can be thinner, and for example 3nm or 5nm perhaps can be thicker.Can be with for example p-type dopant doping Ga 0.98Mn 0.02As layer 11 ', such as beryllium (Beryllium, Be).
As stated previously, can adopt other ferrimagnets.Especially, can adopt other ferromagnetic semiconductors.
AlAs layer 12 ' helps electrically to isolate Ga from substrate 13 ' 0.98Mn 0.02As layer 11 ', and help to Ga 0.98Mn 0.02As layer 11 ' provides clear and definite lower interface 47.
By MBE at Ga 0.98Mn 0.02As layer 11 ' is gone up and is formed AlAs layer 14 '.Tectal thickness is 5nm.Cover layer 14 ' helps to limit Ga 0.98Mn 0.02The oxidation of As layer 11 ' and helping to Ga 0.98Mn 0.02As layer 11 ' provides clear and definite interface, top 48.
Utilize modulation doping can increase Ga 0.98Mn 0.02Carrier concentration in the As layer 11 '.For example, can be for example with p type dopant doping insulation AlAs layer 12 ' or cover layer 14 ', described p type dopant is such as Be.Additionally or alternatively, can be right after under the ferromagnetic semiconductor or be right after the extra play (not shown) that comprises for example GaAs, AlGaAs or AlAs is provided on ferromagnetic semiconductor, the described ferromagnetic semiconductor that mixes is to increase electric charge carrier concentration.
Layer 11 ', 12 ', 14 ' the wafer that comprises substrate 13 ' and have a deposit that superposeed takes out from the reactor (not shown) and handles.This may comprise wafer is divided into less chip.
Can utilize photoetching and wet etching to be identified for the mesa structure (not shown) of zones of different of isolated wafer on the electricity (perhaps chip) and the lead-in wire (not shown) that is used on the electricity device 1 being connected to the welding disking area (not shown) in a kind of known mode.Can in isolated area, make device, as describing now:
With reference to figure 8B, the electron beam photoresistance (not shown) of polymethyl methacrylate (PMMA) form is applied on the upper surface 49 of cover layer 14 '.Wafer (perhaps chip) is loaded in the electron-beam lithography system (not shown) exposes.Figure comprises the negative-appearing image of figure shown in Figure 2.
From the electron-beam lithography system (not shown), take out wafer (perhaps chip), and utilize water and develop wafer (perhaps chip) with the exposure area (not shown) of removing photoresistance and stay patterned photoresist layer 50 as etching mask based on the developer of isopropyl alcohol (IPA).
With reference to figure 8C, wafer (perhaps chip) is placed in active-ion-etch (RIE) the system (not shown).Utilize anisotropy silicon tetrachloride (SiCl 4) etching 51 falls layer 11 ', 13 ', 14 ' not masked portion 51,52 dry etchings.In this example, etching 51 extends in the substrate 13 '.Can adopt such as Cl 2And so on other RIE etchings.Can adopt other dry ecthing methods such as ion beam grinds.Additionally or alternatively, can adopt wet etching.
From RIE system (not shown), take out described wafer (perhaps chip), and utilize acetone to remove described patterned photoresist layer 50.Fig. 8 D has shown corresponding structure.
Other treatment step can comprise introduces damage in free space 8 (Fig. 2).This can be included in opens a window (not shown) and comes gamut ground scanning device 1 (Fig. 1) with ion beam on the free space 8 (Fig. 2) in the electron beam photoresist layer (not shown).Alternatively, described processing comprises with the ion beam (not shown) and optionally scans free space 8 (Fig. 2).
The Curie temperature of ferrimagnet can improve by annealing, for example by Edmond etc. at PhysicAl Review Letters, 92, p.037201 (2004) are described like that.
As mentioned above, in certain embodiments, can adopt the nonferromagnetic zone to replace first ferromagnetic region 6.
Can make the device that comprises conductive region and ferromagnetic region like this, promptly by deposit ground floor material, such as the ferromagnetic semiconductor material, graphical ground floor for example forms the 3rd ferromagnetic region, then deposit second layer material, nonferromagnetic semi-conducting material for example, its coverability graph shapeization ground floor on, and the graphical second layer for example forms the nonferromagnetic zone.Provide tie region by at least one interface zone between first and second materials.
Can make the device that comprises conductive region and ferromagnetic region like this, promptly by material layer of deposit and optionally implanted dopant to form the zone of given type.For example, manufacture method can comprise deposit one deck nonferromugnetic material, such as GaAs, and optionally injects magnetic-doped dose, such as Mn, to form the 3rd ferromagnetic region.Alternatively, manufacture method comprises deposit one deck ferrimagnet, such as (Ga, Mn) As, and optionally inject dopant, such as Si, with damage ferromagnetic region and/or semiconductor, thereby form the nonferromagnetic zone in the position of first ferromagnetic region to afford redress.By inject and not the interface zone of at least one between the injection zone tie region is provided.
Replace grid structure
With reference to figure 9 and 10, except side grid 5 (Fig. 1) was substituted by top grid 5 ', improvement device 1 ' was similar to the device 1 (Fig. 1) in preceding description, and described top grid 5 ' is being positioned on the cover layer 14 on the free space 8.Top grid 5 ' comprises the nonferromagnetic conductor, such as metal or semiconductor.
In this example, top grid 5 ' extends on the cover layer 14 from etched substrate 13.At the extra insulating barrier 54 of deposit nonferromagnetic conductor 5 ' deposit before, so that extend to sidewall sections 18 at conductor 5 ' 3When last ferromagnetic region 8 and conductor 5 ' were isolated.Yet, can be at sidewall sections 18 3On independent side insulation layer (not shown) is provided.Thereby, can ignore described supplemental dielectric layer 54.Can adopt other gating structures.For example, can adopt the lower bottom part grid.
Gate
In traditional microprocessor, gate is not stored the data that they have been exported usually.Thereby in case gate or one group of gate actuating logic computing and output is provided, then output is generally held in the independent memory.The additional step of storage output has hindered calculated performance.
On the contrary, device 1 not only can be used as gate work, can also store computing output, need not storage output in independent memory.
With reference to Figure 11, according to having input A, B and T and output V RGate present device shown in Figure 41.
Input A is operably connected to the 3rd grid 5 and controls reversal of magnetism.Input B is operably connected to resistance 31, passes resistance 31 and device 1 to drive the write or read current impulse.Input T is operably connected to first and second grids 3,4, writes or reads so that device 1 to be set.Between device 1 and resistance 31, obtain output V R
In this example, input A, B, T are provided by source 30,32,33,34 (Fig. 5).Yet, also can provide input by other gate (not shown)s or control element (not shown).
With reference to Figure 12,, apply input T=0 for device 1 being switched to " writing " state.This is by providing V to first and second grids 3,4 G1=V G2=-V 1Realize, as the description of front.
By providing V to the 3rd grid 5 respectively G3=V 2Or V G3=-V 2Import A=0 or A=1 and apply.
With to similar mode noted earlier, have amplitude I by not applying current impulse or applying CDipulse apply input B=0 or B=1 by device 1.
With reference to Figure 13,, apply input T=1 for device 1 being switched to " reading " state.This is by providing V to first and second grids 2,3 G1=V G2=V 1Realize, as the description of front.
Has amplitude I by applying PCurrent impulse by device 1 and measure the bias voltage V stride across device RExport V and read R, as previously described.
With reference to Figure 14, shown the truth table that is used for device 1.
By writing A and B and measuring V RV resets before RFor " 0 " realizes logic " AND ".By writing A and B and measuring V RV resets before RFor " 1 " realizes logic " NAND ".Realize logic " CNOT " by writing A=1 and B=1.
The MAGNETIC RANDOM ACCESS MEMORY array
With reference to Figure 15, comprise the conductive channel 56 and the grid 57 of extension according to magnetic RAM of the present invention (MRAM) unit 55.Except the memory cell 55 as building block does not need to have second fixed area 7, second tie region 10, ties grid 4 and " coercive force adjusting " grid 5 accordingly, memory cell 55 is similar to the conduction control device 1 in preceding description.Yet, as describing in more detail after a while, can memory cell 55 be set in delegation with the alternating series of fixing and free space, wherein adjacent ferromagnetic region is separated by the middle junction zone.
Passage 56 comprises the ferromagnetic region 58,59 that has than high-coercivity and low coercive force. Ferromagnetic region 58,59 is made up of the identical ferrimagnet among patterned layer 67 (Figure 17 A).Yet ferromagnetic region 58,59 can be formed by different ferromagnetic materials, such as ferromagnetic metal and ferromagnetic semiconductor.
Passage 56 comprises tie region 60, and described tie region 60 is magnetically separated ferromagnetic region 58,59.
Tie region 60 is by the part 63 of the first side wall 62 and second opposing sidewalls 63 1Between the narrow part 61 of contracting determine.Second sidewall sections 63 from the plane 1Inside recess towards the first side wall 24 is provided.
With reference to Figure 16, shown the part 64 ' of memory array 64 (Figure 17).
Memory array 64 ' comprises the array of memory cell 55.Each memory cell 55 has 6F 2The unit cell size, wherein F is a characteristic size.Each unit 55 comes addressing by gate line 65 and electric current line 66.
With reference to figure 17A, ferromagnetic region and tie region 58,59,60 are arranged in the patterned ferromagnetic layer 67 that comprises ferromagnetic semiconductor, and described in this example ferromagnetic semiconductor is that to have manganese concentration x be 0.02 gallium-manganese-arsenic thing alloy (Ga 1-xMn xAs), i.e. Ga 0.98Mn 0.02As.
Patterned ferromagnetic layer 67 is positioned on the insulating barrier that comprises insulator 68 of common expansion, although can adopt other insulators, insulator is aluminium arsenide (AlAs) in this example.Insulator can not match with ferromagnetic semiconductor lattice match or lattice.Insulating barrier 68 is positioned on the partially-etched substrate 69, and described partially-etched substrate 69 comprises semi-insulating GaAs (GaAs).The cover layer 70 that comprises AlAs is positioned on the described patterned ferromagnetic layer 67.
Electric current line 66 comprises the conductor such as metal or heavily-doped semiconductor.Electric current line 66 is can right and wrong ferromagnetic.If electric current line 66 comprises metal and if ferrimagnet is a semiconductor, electric current line 66 also can be used as ohmic contact so.Can comprise annealing in order to form the ohmic contact processing.In this example, electric current line 66 comprises as arriving Ga 0.98Mn 0.02The gold layer (Au) of the gold/zinc of the ohmic contact of As (Au/Zn) alloy and stack.Described gold/zinc coating thickness be 50nm and the gold thickness be 200nm.Yet, can adopt other layer thickness.
With reference to figure 17B, grid and electric current line 65,66 are isolated on the electricity by means of the insulating barrier 71 of centre.Intermediate insulating layer 71 can be crystal or amorphous.In this example, insulating barrier 71 comprises silicon dioxide (SiO 2).Yet, can adopt other insulating material, such as silicon nitride (Si 3N 4).Deposition insulating layer 71 before gate line 65.
Gate line 65 comprises the conductor such as metal or heavily-doped semiconductor.Gate line 65 is can right and wrong ferromagnetic.In this example, grid 65 comprises gold (Au) layer of titanium (Ti) adhesion layer and stack.The thickness of titanium be 20nm and the gold thickness be 200nm.Yet, can adopt other layer thickness.
Can be different from and come configurable memory array 64 shown in Figure 16,17A and the 17B.For example, can in plane, form gate line 65 with patterned ferromagnetic layer 67, such as can according to the similar mode of device described above 1, form described gate line 65 from the ferrimagnet identical with patterned ferromagnetic layer 67.If particularly described gate line 65 is under the situation about forming in the plane of patterned ferromagnetic layer 67, electric current line 66 can form on gate line 65.As previously described, can adopt surface or following grid structure to replace the side grid structure.
Alternatively, can under ferromagnetic layer 67, form described electric current line 66, for example, described layer (not shown) is patterned into the strip (not shown) by deposit conductive layer (not shown) on insulating barrier 68, and on the striped of conduction and insulating material the deposit ferromagnetic layer.Graphical then ferromagnetic layer is to form patterned layer 67 and definite gate line 66.Can carry out graphical and gate line definite of ferromagnetic layer at identical or different treatment steps.
With reference to Figure 18, memory array 64 is controlled by row decoder 72 and column decoder 73.
Row decoder 72 is from gate line 65 1, 65 I-1, 65 i, 65 I+1, 65 nIn select a gate line with from memory cell 55 1,1, 55 1, j-2, 55 1, j-1, 55 1, j, 55 1, j+1, 55 1, j+2, 55 1, m, 55 I-1,1, 55 I-1, j-2, 55 I-1, j-1, 55 I-1, j, 55 I-1, j+1, 55 I-1, j+2, 55 I-1, m, 55 I, 1, 55 I, j-2, 55 I, j-1, 55 I, j, 55 I, j+1, 55 I, j+2, 55 I, m, 55 I+1,1, 55 I+1, j-2, 55 I+1, j-1, 55 I+1, j, 55 I+1, j+1, 55 I+1, j+2, 55 I-1, m, 55 N, 1, 55 N, j-2, 55 N, j-1, 55 N, j, 55 N, j+1, 55 N, j+2, 55 N, mMiddle addressing one line storage unit, and with bias voltage V L, V MOr V HApply and select signal to select three different passage conduction modes.
Has bias voltage V LThe selection signal increase electric charge carrier concentration in the tie region 60, thereby the resistance that reduces tie region 60 makes their conductions, preferably leads as ohm electricity.Has bias voltage V MThe electric charge carrier concentration that reduces in the tie region 60 of selection signal make tie region 60 exhaust.Has bias voltage V HThe electric charge carrier concentration that reduces in the tie region 60 of selection signal make tie region the last 60 exhaust, promptly ought apply bias voltage V HThe time depletion region than when applying V MThe time depletion region bigger.V MAnd V HBe and V LIt is reversed polarity.Set forth as the front, can be by the routine test value of obtaining.
Column decoder 73 can be from electric current line 66 1, 66 2, 66 J-2., 66 J-1, 66 j, 66 J+1, 66 J+2, 66 J+3, 66 m, 66 M+1The a pair of adjacent electric current line of middle selection drives has the critical current that is higher than low coercive force ferromagnetic region 59, but is lower than the amplitude than the critical current in high-coercivity zone 58 | I H| the write current pulse, perhaps have the amplitude of the critical current that is lower than low coercive force zone 59 | I M| the read current pulse.Polarity according to the write current pulse writes " 0 " or " 1 ".
With reference to Figure 19, example has illustrated the part 64 ' of writing the memory array 64 during the processing.
To have bias voltage V LWrite and select signal 74 to be applied to capable i, promptly gate line 65 i, will have bias voltage V simultaneously HInhibit signal 75 be applied to other the row, comprise gate line 65 I-1, 65 I+1Thereby, the memory cell 55 among the row i I, j-1, 55 I, j, 55 I, j+1Knot 60 have than low resistance and the memory cell 55 of other row among i-1, i+1 I-1, j-1, 55 I-1, j, 55 I-1, j+1, 55 I+1, j-1, 55 I+1, j, 55 I+1, j+1Knot 60 have high electrical resistance.
Drive write current pulse 76 by row j and j+1, promptly the electric current line 66 j, 66 J+1Current impulse 76 is with sufficiently high current density process memory cell 55 I, jSo that magnetization to be set.Because the knot 60 in these devices is in high resistance state, so other memory cell 55 among the same row j I-1, j, 55 I+1, jCan not be set up.Set forth as the front, the duration of write current pulse 76 is less than 100ns, 10ns or 1ns.In this example, about 1ns of duration.
With reference to Figure 20, example has illustrated the part 64 ' of reading the memory array 64 during the flow process.
To have bias voltage V MRead select signal 77 to be applied to capable i, promptly gate line 65 i, still will have bias voltage V simultaneously HInhibit signal 75 put on other the row, comprise gate line 65 I-1, 65 I+1Thereby, the memory cell 55 among the row i I, j-1, 55 I, j, 55 I, j+1Knot 60 have low resistance, and the memory cell 55 of other row among i-1, i+1 I-1, j-1, 55 I-1, j, 55 I-1, j+1, 55 I+1, j-1, 55 I+1, j, 55 I+1, j+1Knot 60 have high resistance.
Drive read current pulse 78 by row j and j+1, promptly the electric current line 66 j, 66 J+1Current impulse 74 is passed through memory cell 55 with sufficiently high current density I, jSo that magnetization to be set.Because the knot 60 in these devices is in high resistance state, so other memory cell 55 among the same row j I-1, j, 55 I+1, jBe not set up.
Measure electric current line 66 by column decoder 73 (Figure 18) j, 66 J+1The voltage V of the generation at two ends sTo determine whether this unit for example is in corresponding to the high resistance state of " 0 " or corresponding to the low resistance state of " 1 ".
Should be understood that, can make many modifications described embodiment above.Described device needs not to be transversal device as previously described, and can be vertical devices, such as column.
Made foregoing description though one of ordinary skill in the art will be further understood that on the embodiment of the invention, the present invention is not limited to this, can make various changes and modification under the situation that does not break away from spirit of the present invention and accessory claim scope.

Claims (32)

1. conduction control device comprises:
Has first ferromagnetic region than high-coercivity;
Second ferromagnetic region with low coercive force;
Place the tie region between first and second ferromagnetic region, be used for magnetically separating described first and second ferromagnetic region; And
Grid is used for applying electric field with the electric charge carrier concentration in the control tie region to tie region.
2. according to the described device of claim 1, comprise:
The 3rd ferromagnetic region, it has the coercive force that is higher than second ferromagnetic region;
Place another tie region between the second and the 3rd ferromagnetic region; And
Another grid is used for applying electric field to change the electric charge carrier concentration in the tie region to another tie region.
3. device according to claim 1 and 2 further comprises:
Another grid is used for applying electric field to second ferromagnetic region.
4. according to the described device of top any one claim, wherein first and second ferromagnetic region comprise identical materials.
5. according to the described device of top any one claim, wherein first and second ferromagnetic region and tie region comprise identical materials.
6. according to the described device of top any one claim, wherein first and second ferromagnetic region and tie region are formed in one deck.
7. according to the described device of top any one claim, wherein first and second ferromagnetic region comprise ferromagnetic semiconductor.
8. device according to claim 7, wherein ferromagnetic semiconductor comprises (Ga, Mn) As.
9. according to the described device of top any one claim, wherein tie region comprises semi-conducting material.
10. according to the described device of top any one claim, wherein first ferromagnetic region be extend and have a longitudinal axis.
11. device according to claim 10, the wherein said longitudinal axis is positioned on the direction of easy magnetizing axis.
12. according to the described device of top any one claim, wherein, cell configuration is for presenting tunnel anisotropic magnetoresistance (TAMR) effect.
13. according to the described device of top any one claim, wherein, cell configuration is for presenting tunnel magneto resistance (TMR) effect.
14. according to the described device of top any one claim, wherein by be arranged in fact one in the plane one deck or the part of one deck second ferromagnetic region is provided.
15. according to the described device of top any one claim, the thickness of the part of wherein said layer or layer is less than or equal to 10nm.
16. according to claim 14 or 15 described devices, wherein second ferromagnetic region has the easy magnetizing axis outside the plane of a part of layer or layer.
17. according to claim 14,15 or 16 described devices, wherein second ferromagnetic region has the easy magnetizing axis within the plane of a part of layer or layer.
18., wherein provide first ferromagnetic region by being configured in another layer in this plane or another plane or another part of this layer in fact according to any described device in the claim 14 to 17.
19. device according to claim 18, wherein first ferromagnetic region has easy magnetizing axis, and this easy magnetizing axis is within the plane of the part of another layer or another layer.
20. a device comprises:
Conductive region;
Ferromagnetic region;
The tie region that connects conductive region and ferromagnetic region; And
Be used for applying the grid of electric field with the electric charge carrier concentration in the control tie region to tie region.
21. device according to claim 20, wherein conductive region comprises nonferromugnetic material.
22. according to claim 20 or 21 described devices, wherein conductive region comprises semi-conducting material.
23. according to claim 20 or 22 described devices, wherein conductive region comprises semi-conducting material.
24. according to any described device in the claim 20 to 23, wherein, tie region comprises semi-conducting material.
25. according to any described device in the claim 20 to 24, wherein conductive region and tie region comprise identical materials.
26. according to any described device in the claim 20 to 25, wherein ferromagnetic region and tie region comprise identical materials.
27. memory array according to the described device of top any claim.
28. a method of making conduction control device, described method comprises:
First ferromagnetic region that has than high-coercivity is provided;
Second ferromagnetic region with low coercive force is provided;
The tie region that places between first and second ferromagnetic region is provided, is used for magnetically separating described first and second ferromagnetic region; And
Be provided for applying the grid of electric field with the electric charge carrier concentration in the control tie region to tie region.
29. method according to claim 28 wherein provides tie region to comprise the narrow part of determining between first and second tie region that contracts.
30. the method for the channelled conduction control device of operation, described conduction control device comprises: have first ferromagnetic region than high-coercivity, second ferromagnetic region with low coercive force places between first and second ferromagnetic region, is used for magnetically separating the tie region of described first and second ferromagnetic region; And be used for applying electric field to control the grid of electric charge carrier concentration in the tie region to tie region, described method comprises:
Apply first bias voltage to increase the electric charge carrier concentration in the tie region to grid; And
Drive first current impulse by this passage, described current impulse has first current amplitude greater than the critical value of the second ferromagnetic region magnetic reversal.
31. method according to claim 30 comprises:
Apply second bias voltage to reduce the electric charge carrier concentration in the tie region to grid; And
Drive second current impulse by passage, described second current impulse has second current amplitude of subcritical value.
32. the method for the channelled conduction control device of operation, described conduction control device comprises: have first ferromagnetic region than high-coercivity, second ferromagnetic region with low coercive force places between first and second ferromagnetic region, is used for magnetically separating the tie region of described first and second ferromagnetic region; And be used for applying electric field to control the grid of electric charge carrier concentration in the tie region to tie region, described method comprises:
Apply the magnetization of magnetic field with reverse second magnetic regions to described first and second ferromagnetic region, and the magnetization of not reverse first ferromagnetic region, but described magnetic field is higher than the critical magnetic field of second ferromagnetic region is lower than the critical magnetic field of first ferromagnetic region.
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Cited By (2)

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CN101345079B (en) * 2007-07-13 2012-09-05 株式会社日立制作所 Magnetoresistive device
CN103858246A (en) * 2011-09-12 2014-06-11 高通股份有限公司 Strain induced reduction of switching current in spintransfer torque switching devices

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0843827A2 (en) * 1996-06-12 1998-05-27 Koninklijke Philips Electronics N.V. A magneto-resistive magnetic field sensor
JP2000114508A (en) * 1998-09-29 2000-04-21 Fuji Xerox Co Ltd Single electron tunneling element
US6285581B1 (en) * 1999-12-13 2001-09-04 Motorola, Inc. MRAM having semiconductor device integrated therein
JP2002043653A (en) * 2000-07-24 2002-02-08 Taiji Takemura Ferromagnetic tunnel junction memory element

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101345079B (en) * 2007-07-13 2012-09-05 株式会社日立制作所 Magnetoresistive device
CN103858246A (en) * 2011-09-12 2014-06-11 高通股份有限公司 Strain induced reduction of switching current in spintransfer torque switching devices
CN103858246B (en) * 2011-09-12 2016-10-12 高通股份有限公司 The reduction of the switching electric current caused by strain in spin-transfer torque switching equipment

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