CN102246237B - Multibit multiferroic memory element - Google Patents
Multibit multiferroic memory element Download PDFInfo
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- CN102246237B CN102246237B CN200980149958.4A CN200980149958A CN102246237B CN 102246237 B CN102246237 B CN 102246237B CN 200980149958 A CN200980149958 A CN 200980149958A CN 102246237 B CN102246237 B CN 102246237B
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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
- G11C11/56—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
- G11C11/5607—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency using magnetic storage elements
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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
- G11C11/161—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 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
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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
- G11C11/165—Auxiliary circuits
- G11C11/1673—Reading or sensing circuits or methods
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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
- G11C11/165—Auxiliary circuits
- G11C11/1675—Writing or programming circuits or methods
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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
- G11C11/56—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
- G11C11/5657—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency using ferroelectric storage elements
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Abstract
A memory element (1) comprises a source electrode (12), a drain electrode (13) and a gate, wherein a memory state of the memory element is switchable by application of a voltage signal to the gate, and is readable by measuring a current-voltage characteristic between the source electrode and the drain electrode across a channel region (21). The gate comprises a multiferroic material (15). A magnetic field may be generated in the channel region (21). According to the invention, the multiferroic material (15) comprises a first and a second stable domain (15.1; 15.2), wherein a switching state of the first domain is set by application of a first write voltage signal between a gate electrode and the source electrode, and a switching state of the second domain is set by application of a second write voltage signal between the gate electrode and the drain electrode, whereby the memory element is a 2-bit memory element.
Description
Technical field
The present invention relates to the field of the memory component (memory cell) for storer.
Background technology
Storer is the primary categories of integrated circuit.It is mainly used as solid-state independence and in-line memory.The most widely used memory technology is DRAM, SRAM, floating grid (flash memory) and MRAM.These prior aries all can not be in addition integrated and non-volatile and fast operating can not be provided simultaneously with high area density.Especially, flash memory is too slow for many Embedded Application, and SRAM and DRAM are discharging its memory state in the time that power supply disconnects, and SRAM and MRAM only can be manufactured by limited area density.In NROM, MirrorBit and SONOS flash memory, reach high density, it comprises electric charge capture layer to store the electric charge package of two physical separation.The high programming voltage of flash memory makes to become complicated with the integrated of cmos circuit.
Therefore, a kind of memory component of defect of the memory cell that overcomes prior art need to be provided.Especially be to provide a kind of non-volatile and make in addition high area density and/or fast operating become possible memory component.
Summary of the invention
Memory component according to a first aspect of the invention comprises source electrode-drain electrode-gate electrode function structure, that is, between it, set up the source electrode and the drain electrode that there are channel region, wherein depend on electric signal is applied to grid, electric charge carrier can flow between source electrode and drain electrode.
Preferably, channel region can comprise semiconductor or insulating material (therefore comprising equal minority free charge charge carrier at the most) or through being doped to conduction; Can configure channel region by many different modes; Preferably, channel region provides enough large resistance to allow the independent voltage signal between grid (on the one hand) and source electrode or drain electrode (on the other hand).
Grid comprises multi-ferroic material (therefore for having at least two materials that are coupled with order parameter).Multi-ferroic material is generally to arrange and is positioned between gate electrode (on the one hand) and source electrode and drain electrode (on the other hand).Memory component is through being formed as 2 bit memory elements.This is by making multi-ferroic material comprise that two stable farmlands realize, wherein the switching state on the first farmland is set by apply first " writing " voltage signal between gate electrode and source electrode, and the switching state on the second farmland is set by apply second " writing " voltage signal between gate electrode and drain electrode.This farmland alternatively (for example) by the crack between it or domain wall pinning structure and physical separation.Or or in addition, in a preferred embodiment of the invention, it can be by cause " writing " signal controlling to apply the first write pulse all the time and the second write pulse occurs simultaneously, even if the only one in two positions will rewrite.
Because two farmlands are enough stored in single memory component two potential energies, so compare with the memory component of prior art, area density increases.Although compare with the similar memory component only with a farmland, contact etc. (it takies the most of region on device) is identical, but memory density is increased 2 times, because comprise two information bits by the memory component of the proposed simple measurement according to the present invention.
It is stable and can be by sluggish the spontaneous polarization of switching through applying electric field that ferroelectric substance has.Ferrimagnet has spontaneous magnetization stable and that can switch by the magnetic field applying.Multi-ferroic material has ferroelectricity ordering simultaneously and magnetic order.These two order parameters are coupled.There is ferromagnetism, inferior ferromagnetism and antiferromagnetism multiferroic (multiferroics).
Therefore, multi-ferroic material farmland can apply the first voltage signal and second voltage signal (for example,, by applying electric field pulse) is programmed by crossing over it.Coupling owing to ferromagnetism, inferior ferromagnetism or antiferromagnetism order parameter to ferroelectricity order parameter, causes this ferromagnetism, inferior ferromagnetism or antiferromagnetism order parameter to be programmed equally.
For " reading " operation, can use spin valve effect (spin valve effect).Spin valve effect causes resistance between changeable source electrode and drain electrode (at upwards mobile electric current between source electrode and drain electrode of at least one party).For this purpose, drain electrode and source electrode are all preferably ferromagnetic or at least comprise ferromagnetic component.Equally, multi-ferroic material can affect the relative orientation of magnetic moment and the magnetized relative orientation of source electrode or drain electrode of the electric charge carrier that flow to source electrode or drain electrode.This can two kinds one in may modes carry out:
-as the first alternative, multi-ferroic material can cause producing State-dependence magnetic field, the magnetic moment of influence of magnetic field mobile electric charge carrier in conducting channel.The switching of therefore, ferromagnetism/time ferromagnetism/antiferromagnetism order parameter causes the switching in magnetic field in channel region.This can be undertaken by the following:
Zero grid ferromagnet (or is grid time ferromagnet potentially; In this article, definition " grid ferromagnet ", " ferromagnet ", " ferromagnetic layer " or " ferrimagnet " comprise time ferrimagnet that conforms to, and those who familiarize themselves with the technology knows ferromagnetic function also can be by time ferromagnet realization) be coupled to multi-ferroic material; Then, grid ferromagnet directly contacts (directly contacting without any thing in the situation that middle) with multi-ferroic material,
Zero then, and ferromagnetism (or inferior ferromagnetism) multi-ferroic material self produces enough large stray magnetic field.
-as the second alternative, the switching of the ferromagnetism on the first farmland and the second farmland/time ferromagnetism/antiferromagnetism order parameter can cause respectively the switching of the direction of magnetization of source electrode and drain electrode, makes Spin Valve change the preferred orientation of electric charge carrier magnetic moment.For this purpose, source electrode is directly exchange-coupled to the first farmland of multi-ferroic material, and drain electrode is exchange-coupled to the second farmland.This with for example, for causing device that the magnetic moment of the electric charge carrier that flow to source electrode and drain electrode has a predetermined preferred orientation (, fixed magnetization (pinning) grid ferromagnet, its stray magnetic field is orientated the magnetic moment of electric charge carrier in the time that electric charge carrier flows into channel region) combination.
Under arbitrary situation, rely on respectively with deputy " reading " process the generation that causes electric charge carrier to flow to the electric current of source electrode and drain electrode for first.Preferably, this reaches by apply " reading " pulse between source electrode and drain electrode.Under most of general status, it is that polarity relies on that above-mentioned spin valve effect causes voltage-current characteristic.Depend on the polarity of " reading " pulse, read first or second.This also shows that memory component is not completely random access type, because can not read first and second simultaneously.But, the position of different memory element in read memory simultaneously.
Memory component is to have non-volatile advantage as feature, because the ferroelectricity order parameter of multi-ferroic material and magnetic order parameter are non-volatile.Owing to its non-volatile nature, can expect low power consumption.
Equally, the ferroelectricity of change multiferroic element is polarized to intrinsic Fast Process (50ps-1ns).Therefore, (1 μ s) compares and has remarkable program speed advantage memory component according to the present invention with flash memory.
In addition, memory component may be implemented in simple small-sized unit primitive and (only has the requisite space of 6F2, in the 1-transistor arrangement without any extra resistors or capacitor) in, and therefore compare with the memory component of prior art and be suitable for integrated with higher area density.Equally, it is adjusting in proportion well when compared with junior unit, because it does not comprise any capacitor.
The write energy (approximately 10 of the another advantage (especially comparing with MRAM) of memory component for reducing
-15joule/position, with respect to 10 of MRAM
-11joule/position).
An advantage again (especially comparing with flash memory) of memory component is lower program voltage (approximately 1V, with respect to the 15V of flash memory).
Possible ferromagnetism multiferroic comprises boracite (Ni
3b
7o
13i), perovskite (for example, BiMnO
3and TbMnO
3) and sulfate (such as, CdCr
2s
4).But in these current known materials, being coupled with order parameter is only non-zero at low temperatures, make memory component and the device that makes with it is mainly suitable for accepting the special applications of cooling device.
In a preferred embodiment, element comprises cooling device.The operating temperature of the memory component preferably, providing by this cooling device is lower than 100 Kelvins (Kelvin).
But according to preferred embodiment especially, multi-ferroic material is for coupling (general by the coupling of exchange bias voltage) is to multiferroic antiferromagnet of grid ferromagnet or drain electrode and source electrode and pinning grid ferromagnet or drain electrode and source electrode.This " ferromagnet pinning " embodiment first take known antiferromagnetism multiferroic than its ferromagnetism homologue more the advantage of temperature stabilization as feature.Equally, exist the superparamagnetic limit (that is, size when magnetospheric magnetic anisotropy becomes suitable with kT in primitive, wherein k is that Boltzmann (Boltzmann) constant and T are absolute temperature, make magnetization below the limit, become unstable at that) not the special benefits of the problem in antiferromagnet, make unit can be designed to less on an equal basis and be still stable.
The example of available antiferromagnetism multi-ferroic material is BiFeO
3.
Memory component according to the present invention can be used as the memory cell of pure storage component part and comprise memory cell in the logical circuit of FPGA (Field Programmable Gate Array) both.Can in European patent application EP08104301.0, find the example of these logical circuits that can be incorporated to good grounds storage component part of the present invention.Therefore, owing to the method according to this invention, can be without additional masking steps in the situation that integrated memory and logical circuit, this provides significant manufacturing cost advantage for this integrated circuit.
Accompanying drawing explanation
Hereinafter, will embodiments of the invention be described referring to accompanying drawing.Accompanying drawing is schematically and not in scale.In the accompanying drawings, identical reference number refers to identical or respective element.
Fig. 1 shows according to the xsect of the first embodiment of memory component of the present invention;
Fig. 2 describes according to the xsect of the second alternate embodiment of memory component of the present invention;
Fig. 3 a to Fig. 6 c shows " writing " step and " reading " step of four logic states being taked by the device of Fig. 2;
Fig. 7 describes according to the xsect of the another alternate embodiment of memory component of the present invention;
Fig. 8 a to Figure 11 c shows " writing " step and " reading " step of four logic states being taked by the device of Fig. 7; And
Figure 12 shows according to an embodiment again of memory component of the present invention.
Embodiment
In the ferrimagnet of the element of describing at Zhu Tusuo, filled arrows is indicated fixed magnetization conventionally.Fixed magnetization can be with the magnetization of pinning in addition of a certain mode, and it has the coercive field higher than the summation of the effective field being applied to it in the normal operation period, or it changes direction of magnetization during the normal running of the journey element that otherwise affects not to be on the permanent staff.Hollow arrow is indicated the magnetization that can switch by program voltage pulse signals.Under the magnetized situation of pinning, in all figure, do not show pinning layer.The pinning of ferromagnetic layer is for example known from mram memory by haveing the knack of magnetic storage field person.No longer further discuss pinning herein.
The memory component 1 that Fig. 1 describes comprises source electrode 12 and drain electrode 13 on substrate 3, both all have ferromagnetic conductive material source electrode 12 and drain electrode 13, for example, cobalt-base alloy or Alperm (permalloy) (FeNiCo alloy).Between source electrode and drain electrode, for example form conducting channel 21 by the N-shaped doped region in substrate or with any other appropriate ways; But conducting channel may be without comprising the material identical with substrate 3.
Substrate can be any known or other suitable substrate, such as, semiconductive substrate, for example, gallium arsenide or silicon.The substrate of being described in embodiment is that referenced voltage contact (, ground contact 8 (or " body (bulk) " contact)) institute contacts.As known in the art, between for example source electrode 12 and ground contact 8, can exist (not describing) to be connected, make source electrode 12 all the time in ground potential (or optionally in other reference potential), or as an alternative, between gate electrode and ground contact, can exist and be connected, as below further described.
The coupling being made up of multiferroic layer 15 and ferromagnetic layer 14 is double-deck now for making it can comprise two stable farmlands: 14.1,15.1; 14.2,15.2.Dotted line 18 in this figure is described the electromotive force defiber between the first farmland 14.1,15.1 and the second farmland 14.2,15.2.
Can separate farmland by the structure of on purpose being added at fixed position place.This structure plays a part to divide partly double-deck or serves as domain wall pinning device.This structure can be for example the micro chink of the position of dotted line, or impurity or similar pinning domain wall.
As the alternative of the structure of on purpose being added, double-deck any structure of on purpose being added that also can lack to separate farmland.Farmland can be arranged in non-predefine position and can only occur by cause different order parameter directions near drain electrode and source electrode respectively.
Under any situation, bilayer is necessary for anisotropy and enough large size is to maintain two farmlands after cutting off, that is under any situation, two farmlands must be stable, and it is non-volatile making memory component.For example, in the structure of being down to () 20nm or even less very small dimensions, predict and observe coexisting of two magnetic stability farmlands.Make the lower limit of the stable double-deck size in farmland depend on anisotropy, anisotropy depends on again double-deck material composition.
Can between gate electrode 17 and source electrode 12 or between gate electrode 17 and drain electrode 13, apply " writing " voltage signal for two farmlands respectively.For this purpose, preferably make thickness and the electric conductivity of multiferroic layer 15 and dielectric layer 16 adapt to each other, make to cross over the voltage drop of multiferroic layer corresponding to the major part (being preferably at least half) of the voltage between gate electrode and source electrode or drain electrode.
By writing voltage signal, the spontaneous polarization that can switch multi-ferroic material between four kinds of states (each farmland two states), as explained in more detail referring to Fig. 3 a to Fig. 6 c.Because material is multiferroic, so the switching of spontaneous polarization also for example switches by putting upside down the order of " upwards " and " downwards " magnetized layer in multi-ferroic material the antiferromagnetism order parameter that conforms to.Ferromagnetic layer 14 (being in close proximity to multiferroic layer 15) is exchange-coupled to multiferroic layer.Thus, in the farmland 15.1,15.2 of multi-ferroic material, the switching of ferroelectricity spontaneous polarization has the effect of the direction of magnetization on same switching ferromagnetic layer farmland 14.1,14.2.
The design part that memory component 1 design of Fig. 2 is different from Fig. 1 is: the reversed order of the order of multiferroic layer 15 and ferromagnetic layer 14.Multiferroic layer 15 is sandwiched between ferromagnetic layer 14 (side) and conducting channel 21 and source electrode and drain electrode (opposite side).No longer need dielectric layer 16, because contrast with the normally used ferrimagnet of major part, multi-ferroic material 15 is electrical isolation.
Equally, grid electrode layer 17 is optional and attached not shown separately, because ferromagnetic layer 14 self can optionally serve as gate electrode.
Same in the configuration of Fig. 2, can between gate electrode (ferromagnetic layer 14) and source electrode 12 or drain electrode 13, apply and write voltage signal.With the configuration contrast of Fig. 1, almost whole voltage drop will be crossed over multiferroic layer, make to compare with the configuration of Fig. 1 the required lower voltage that writes.Therefore, the configuration of Fig. 2 is generally preferred.
By Fig. 3 a to Fig. 6 c, explain the principle of work according to memory component of the present invention referring to the embodiment of Fig. 2, explain thus " writing " operation and " reading " operation of memory component.
Fig. 3 a, Fig. 4 a, Fig. 5 a and Fig. 6 a represent " writing " process of four kinds of different conditions for being taked by two bit units." write " in process at each, between gate electrode 14 and source electrode 12, between gate electrode 14 and drain electrode 13, apply on the other hand on the one hand " writing " voltage signal (putting upside down the only one (therefore putting upside down the only one in two farmlands) in two positions if same) simultaneously.For example, can during each " writes " process, make gate electrode 14 be held in 0V electromotive force, and to source electrode and drain electrode all supply independently 1V or-1V " writes " pulse.
Fig. 3 a for example, corresponding to () by obtaining " upwards-upwards (up-up) " state to apply-1V of source electrode and drain electrode pulse.Fig. 3 b represents that " upwards-downwards (up-down) ", (1V was applied to source electrode to state, + 1V is applied to drain electrode), Fig. 3 c represents " downwards-upwards (down-up) " state (+1V/-1V), and Fig. 3 d represents "-downwards (down-down) " state (+1V/+1V) downwards.
Certainly, in this article, the amount of the voltage applying and absolute polarity thereof are pure example.
Be not completely random access according to memory component of the present invention.Can not read first information position and second information bit of each memory component simultaneously.Fig. 3 b, Fig. 4 b, Fig. 5 b and Fig. 6 b show respectively " reading " process for the first information position of " upwards-upwards " state, " upwards-downwards " state, " downwards-upwards " state and " downwards-downwards " state, and Fig. 3 c, Fig. 4 c, Fig. 5 c and Fig. 6 c show " reading " process for its second information bit.
The process that " reads " is based on spin valve effect.For " reading " operation, depend on and read first or read second, between source electrode and drain electrode, apply little " reading " potential pulse of wishing polarity.This causes electric charge carrier (depend on conductivity-type and be N-shaped electric charge carrier or p-type electric charge carrier) to flow into the channel region between source electrode and drain electrode.Electric charge carrier is by the arrow symbol in channel region 21 in these accompanying drawings, and arrow represents the magnetic moment of electric charge carrier.Block arrow illustrates its flow direction.When through channel region 21, electric charge carrier stands the magnetic field being produced by ferromagnetic layer 14.In the situation that electric charge carrier stands magnetic field, the orientation of the magnetic moment of electric charge carrier is determined in this magnetic field.
Therefore, when electric charge carrier enters after ferromagnetism source electrode or drain electrode, the orientation of electric charge carrier is defined respectively near the farmland electrode (be source electrode for primary " reading " process, and be drain electrode for deputy " reading " process) flowing at electric charge carrier.
To distinguish two kinds of situations.If the magnetic moment of most of electric charge carriers is through being orientated to the magnetization that is parallel to its source electrode flowing to or drain electrode, the electric charge carrier with the magnetic moment through maintaining can easily enter electrode.Contrast therewith, if electric charge carrier is antiparallel to through being orientated to the electrode that it flow to, it meets with energy barrier (for example,, in order again to reverse its magnetic moment) in the time entering electrode material.This energy barrier effect (being called as ' Spin Valve ' effect) is also similar in essence and causes the effect of ' giant magnetoresistance ' or ' tunnel magneto ' and thereby be described in document.
" reading and " meeting with low-yield potential barrier (each first or second for " upwards " or " 1 ") in configuration at Fig. 3 b, Fig. 3 c, Fig. 4 b and Fig. 5 c.Sensing high-energy potential barrier in Fig. 4 c, Fig. 5 b, Fig. 6 b and Fig. 6 c (each first or second be " downwards " or " 0 ").
Therefore, source electrode 12 (for first) and drain electrode 13 (for second) serve as the ferromagnetism detecting device for the orientation on its contiguous farmland.The stray magnetic field of ferromagnetic layer 14 affected electric charge carrier before electric charge carrier flows into each electrode.(polarity dependence) I-E characteristic is for being almost independent of the ferromagnetism farmland orientation on another farmland (that is, further from the farmland of detecting electrode).This is by the small arrow example in Fig. 4 b, Fig. 4 c, Fig. 5 b and Fig. 5 c.For example, in the configuration of Fig. 4 b, be the magnetization that is parallel to drain electrode by initial polarization from the magnetic moment of the electric charge carrier of drain electrode 13, because drain electrode is ferromagnetic.Under the impact on the second farmland, magnetic moment enters partially or even wholly reversing before the region of the magnetic field that electric charge carrier is subject to the first farmland (it causes magnetic moment upset) impact at electric charge carrier.
As remarks, depend on the electronic structure of source electrode and drain electrode ferrimagnet, under some situations, spin valve effect can opposite way work: that is the electric charge carrier with parallel magnetic moment is compared and can then be met with more high-energy potential barrier with antiparallel magnetic moment electric charge carrier.Situation when this can be for example included in most of so-called " by force " ferromagnet not existing in can band for the free state of electric charge carrier for drain electrode material.But, in order to reach object of the present invention, it is identical that effect keeps: only importantly have in the I-E characteristic between the situation that the situation of the magnetized magnetic moment that is parallel to its electrode flowing to and electric charge carrier have the magnetized magnetic moment that is antiparallel to its electrode flowing to and have certain species diversity at electric charge carrier.In other words, it is not identical that polarity for example relies on, for magnetized two different relative orientations of the electrode that voltage-current characteristic (electric current, being produced by specific " reading " voltage through applying or for reaching specifically " reading current " required voltage) flow to for electric charge carrier magnetic moment and electric charge carrier.
Fig. 7 has illustrated alternate embodiment, and wherein grid ferromagnetic layer 34 has fixed magnetization, and the magnetization exchange of source electrode 12 and drain electrode 13 is coupled to multiferroic layer 15 and can be overturn by the order parameter of upset multiferroic layer 15.In this configuration, source electrode need to carry out direct physical with multiferroic layer with drain electrode and contact.But, do not need direct contact the between multi-ferroic material 15 and pinning grid ferromagnet 34.Truth is, between pinning grid ferromagnet 34 and multi-ferroic material 15, can there are a kind of a layer or some layers of (not shown) of other material/multiple other material, for example,, for preventing the metal nonmagnetic layer of the exchange coupling between grid ferromagnet 34 and multi-ferroic material 15.
Fig. 8 a to Figure 11 c shows for the ablation process of embodiment as shown in Figure 7 and reads process.This representation class is similar to the expression of Fig. 3 a to Fig. 6 c.
Be similar to the embodiment of Fig. 1 and Fig. 2, in " writing " process, can set respectively the first farmland 15.1 of multi-ferroic material and the orientation on the second farmland 15.2 by " writing " voltage signal between gate electrode 34 and source electrode 12 and drain electrode 13, as illustrated in Fig. 8 a, Fig. 9 a, Figure 10 a and Figure 11 a.Owing to exchange coupling, with which, the same magnetization of setting (programming) source electrode and drain electrode, this is similar to the programming on farmland 14.1,14.2 in the embodiment of Fig. 1 and Fig. 2.
In " reading " process, electric charge carrier magnetic moment in the time being injected in channel region 21 polarizes according to the polarization of electrode that is provided with injecting it, but through after channel region 21 always according to the magnetic field of gate electrode (describe to configure in for upwards) polarize.Therefore, the embodiment of Fig. 7 produces following electric charge carrier reading in process: electric charge carrier has predetermined magnetic moment orientation in the time flowing to source electrode 12 or drain electrode 13.Therefore,, owing to spin valve effect as described above, charge carriers flow is served as the pick-up unit for detection of the magnetization orientation of source electrode or drain electrode.
Finally, Figure 12 describes another embodiment.In this embodiment, the multiferroic layer 35 that has two farmlands 35.1,35.2 is multiferroic ferromagnet.Therefore, multiferroic layer 35 directly produces magnetic field, and without extra ferromagnetic layer 14.Aspect other, principle of work is same as the principle of work of the embodiment of Fig. 2.
Other variant of the present invention is possible.For example, having in the magnetized embodiment of changeable source electrode and drain electrode, limit the magnetic field of magnetic moment orientation of the electric charge carrier that flow to source electrode and drain electrode without belonging to grid.Truth is, also alternately uses " universe (the global) " Magnetic Field Source producing for the uniform magnetic field of the hope of multiple memory components, for example, and common ferromagnetism coating, or outside ferromagnet, electromagnet etc.
Claims (5)
1. a memory component, it comprises source electrode (12), drain electrode (13) and grid, the memory state of wherein said memory component can be switched by applying voltage signal to described grid, and the I-E characteristic that can measure between described source electrode and described drain electrode by leap channel region (21) is read, wherein said grid comprises multi-ferroic material (15, 35), and wherein said memory component comprises the device for produce magnetic field at described channel region (21), it is characterized in that, described multi-ferroic material (15, 35) comprise that first stablizes farmland and second and stablize farmland (15.1, 35.1, 15.2,35.2), the switching state on wherein said the first farmland writes voltage signal and is set by apply first between gate electrode and described source electrode, and the switching state on described the second farmland writes voltage signal and is set by apply second between described gate electrode and described drain electrode, thus, described memory component is 2 bit memory elements,
Wherein said multi-ferroic material is multiferroic antiferromagnet, wherein said grid also comprises grid ferromagnet (14) or the inferior ferromagnet that can cause existing magnetic field in described channel region, described grid ferromagnet or inferior ferromagnet are coupled to described multiferroic antiferromagnet, the direction of magnetization on described grid ferromagnet or inferior ferromagnetic the first farmland and the second farmland be attributable to described first write voltage signal and described second write voltage signal described in apply and by being switched to the described coupling of described multiferroic antiferromagnet.
2. according to the memory component of claim 1, wherein said multiferroic antiferromagnet (15) is arranged between described grid ferromagnet (14) or inferior ferromagnet and described channel region (21).
3. according to the memory component of claim 2, wherein said multiferroic antiferromagnet (15) is close to described channel region (21) setting.
4. a memory component, it comprises source electrode (12), drain electrode (13) and grid, the memory state of wherein said memory component can be switched by applying voltage signal to described grid, and the I-E characteristic that can measure between described source electrode and described drain electrode by leap channel region (21) is read, wherein said grid comprises multi-ferroic material (15, 35), and wherein said memory component comprises the device for produce magnetic field at described channel region (21), it is characterized in that, described multi-ferroic material (15, 35) comprise that first stablizes farmland and second and stablize farmland (15.1, 35.1, 15.2,35.2), the switching state on wherein said the first farmland writes voltage signal and is set by apply first between gate electrode and described source electrode, and the switching state on described the second farmland writes voltage signal and is set by apply second between described gate electrode and described drain electrode, thus, described memory component is 2 bit memory elements,
Wherein said multi-ferroic material is multiferroic antiferromagnet, described the first farmland and described two farmlands are coupled to respectively in the magnetization of wherein said drain electrode and the magnetization of described source electrode, and can be respectively owing to described first write voltage signal and described second write voltage signal described in apply and switched by the described coupling to described multi-ferroic material.
5. a storage arrangement, it comprises and serves as the multiple according to the memory component (1) of any one in aforementioned claim of memory cell, and further comprise the contact that individually applies electric signal for the grid to described memory component, and for by determine contacting that I-E characteristic between source electrode and the drain electrode of the memory component of indivedual addressing reads in polarity dependence mode.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP08172722 | 2008-12-23 | ||
| EP08172722.4 | 2008-12-23 | ||
| PCT/IB2009/055875 WO2010073211A1 (en) | 2008-12-23 | 2009-12-21 | Multibit multiferroic memory element |
Publications (2)
| Publication Number | Publication Date |
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| EP (1) | EP2374132A1 (en) |
| CN (1) | CN102246237B (en) |
| TW (1) | TW201027715A (en) |
| WO (1) | WO2010073211A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| EP2631912A1 (en) * | 2012-02-27 | 2013-08-28 | Hitachi Ltd. | Field-effect transistor with magnetic layer |
| US9548117B2 (en) | 2013-12-06 | 2017-01-17 | Empire Technology Development Llc | Non-volatile SRAM with multiple storage states |
| US10163917B2 (en) * | 2016-11-01 | 2018-12-25 | Micron Technology, Inc. | Cell disturb prevention using a leaker device to reduce excess charge from an electronic device |
| CN108206204B (en) * | 2016-12-16 | 2020-07-07 | 同济大学 | Spin filtering heterojunction device based on cobalt-molecular multiferroic material and preparation thereof |
| GB2560936A (en) * | 2017-03-29 | 2018-10-03 | Univ Warwick | Spin electronic device |
| CN108445058B (en) * | 2018-03-07 | 2023-06-06 | 重庆科技学院 | Multiferroic liquid physical property testing device |
| CN108899058A (en) * | 2018-06-08 | 2018-11-27 | 复旦大学 | The operating method of the four state ferroelectric transistor memories based on source drain regions otherness iron electric polarization |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002270789A (en) * | 2001-03-14 | 2002-09-20 | Toshiba Corp | Ferroelectric memory |
| EP1603168A1 (en) * | 2003-03-07 | 2005-12-07 | Japan Science and Technology Agency | Field-effect transistor with spin-dependent transmission characteristic and nonvolatile memory using same |
| WO2007110950A1 (en) * | 2006-03-29 | 2007-10-04 | Fujitsu Limited | Semiconductor memory device and method of manufacturing same |
| CN101068036A (en) * | 2006-05-04 | 2007-11-07 | 株式会社日立制作所 | Magnetic memory device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US6741494B2 (en) * | 1995-04-21 | 2004-05-25 | Mark B. Johnson | Magnetoelectronic memory element with inductively coupled write wires |
| US6071393A (en) | 1996-05-31 | 2000-06-06 | Ngk Spark Plug Co., Ltd. | Nitrogen oxide concentration sensor |
| JP4785180B2 (en) * | 2004-09-10 | 2011-10-05 | 富士通セミコンダクター株式会社 | Ferroelectric memory, multilevel data recording method, and multilevel data reading method |
| JP4693634B2 (en) * | 2006-01-17 | 2011-06-01 | 株式会社東芝 | Spin FET |
| GB0603985D0 (en) * | 2006-02-28 | 2006-04-05 | Univ Cambridge Tech | Multi-bit memory cell structures and devices |
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- 2009-12-21 WO PCT/IB2009/055875 patent/WO2010073211A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002270789A (en) * | 2001-03-14 | 2002-09-20 | Toshiba Corp | Ferroelectric memory |
| EP1603168A1 (en) * | 2003-03-07 | 2005-12-07 | Japan Science and Technology Agency | Field-effect transistor with spin-dependent transmission characteristic and nonvolatile memory using same |
| WO2007110950A1 (en) * | 2006-03-29 | 2007-10-04 | Fujitsu Limited | Semiconductor memory device and method of manufacturing same |
| CN101068036A (en) * | 2006-05-04 | 2007-11-07 | 株式会社日立制作所 | Magnetic memory device |
Also Published As
| Publication number | Publication date |
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| CN102246237A (en) | 2011-11-16 |
| WO2010073211A1 (en) | 2010-07-01 |
| EP2374132A1 (en) | 2011-10-12 |
| TW201027715A (en) | 2010-07-16 |
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