CN104332557A - Nonvolatile memory based on single-wall carbon tube and preparation method thereof - Google Patents
Nonvolatile memory based on single-wall carbon tube and preparation method thereof Download PDFInfo
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- CN104332557A CN104332557A CN201410444235.XA CN201410444235A CN104332557A CN 104332557 A CN104332557 A CN 104332557A CN 201410444235 A CN201410444235 A CN 201410444235A CN 104332557 A CN104332557 A CN 104332557A
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Abstract
The invention discloses a nonvolatile memory based on a single-wall carbon tube and a preparation method thereof and belongs to the field of memories. The memory includes a substrate; a first electrode which is formed on the substrate and is a metal material used for executing a reading function; a second electrode which is formed on the substrate and is a ferromagnetic material used for executing a writing function; a third electrode which is formed on the substrate and is a metal material used for executing an erasure function; and a single-wall carbon tube, the fixing end of which is fixed in the first electrode and the opening end of which is suspended over the second electrode. The second electrode is between the first electrode and the third electrode. The length of the single-wall carbon tube is enough so that the opening end of the single-wall carbon tube contacts the second electrode after the single-wall carbon tube is bent. The nonvolatile memory based on the single-wall carbon tube has the characteristics of being small in size, little in heating, low in energy consumption, high in storage speed and long in service life so that the integration degree of an integrated circuit and a device is improved.
Description
Technical field
The present invention relates to memory area, particularly relate to a kind of nonvolatile memory based on single-wall carbon tube and preparation method thereof.
Background technology
The past few decades integrated circuit technique obtains the development of advancing by leaps and bounds, and is that the information industry of core has become mainstay of the national economy industry with integrated circuit.Memory plays a key effect in the growth of information industry.
In prior art, the kind of memory mainly contains ferroelectric memory (FRAM), magnetic memory (MRAM), phase transition storage (PRAM) and resistance-variable storing device (RRAM), be stably non-volatility memorizer, but memory mechanism is different: FRAM has self poling characteristic, still keep when electric field removes after-polarization characteristic; MRAM utilizes two direction of magnetizations of magnetic material to store binary message, and utilize current induced magnetic field to change the direction of magnetization written information of material, when not having externally-applied magnetic field, the direction of magnetization of material remains unchanged; PRAM utilizes material conversion between crystalline and amorphous, is low resistance when material is in crystalline state, is high resistance, utilizes the conversion of this two states to realize the storage of binary message when being in amorphous state; RRAM utilizes the reversible transformation of resistivity of material to realize the storage of binary message.
But, existing memory hinders the further raising of integration density due to size is comparatively large, energy consumption is high, caloric value is large and store status is unstable reason, define the bottleneck of memory development, correspondingly, the integrated level of integrated circuit and device cannot continue to improve.
Summary of the invention
In view of this, the embodiment of the present invention proposes a kind of nonvolatile memory based on single-wall carbon tube and preparation method thereof, with reduce memory size, reduce the energy consumption of memory and caloric value, quickening memory speed and extend life-span of memory.
For reaching this object, the technical solution used in the present invention is as follows:
First aspect, embodiments provides a kind of nonvolatile memory based on single-wall carbon tube, comprising:
Substrate;
First electrode, is formed in described substrate, and the material of described first electrode is metal material, for performing " reading " function;
Second electrode, is formed in described substrate, and the material of described second electrode is ferrimagnet, for performing " writing " function;
Third electrode, is formed in described substrate, and the material of described third electrode is metal material, for performing " wiping " function;
Single-wall carbon tube, the stiff end of described single-wall carbon tube is fixed in described first electrode, and the openend of described single-wall carbon tube is suspended on above described second electrode;
Described second electrode between described first electrode and third electrode, after the length of described single-wall carbon tube is enough to make it bending, the openend of described single-wall carbon tube and described second electrode contact.
Further, the thickness of described first electrode is greater than the height of described single-wall carbon tube apart from described substrate.
Further, the material of described substrate is nonmetallic materials or nonmetal oxide material, and the surface of described substrate has insulating barrier, and wherein, the material of described substrate is Si or SiO
2, the material of described insulating barrier comprises SiO
2, Al
2o
3or HfO
2in the composition of any one or at least two kinds.
Further, the metal material of described first electrode and the metal material of described third electrode are the composition of any one or at least two kinds in Au, Ag, Cu, W, Ti, Pt, Fe, Co or Ni, and described ferrimagnet is Fe, Co, Ni or ferrimag.
Further, described single-wall carbon tube is single single-wall carbon tube or single-wall carbon tube film.
Second aspect, embodiments provides a kind of preparation method of the nonvolatile memory based on single-wall carbon tube, comprises the following steps:
Spin coating first photoresist in substrate;
Utilize direct electronic beam writing technology, the first shape and size according to presetting etch the first photoresist, deposited iron magnetic material, form the second electrode after removing described first photoresist;
Spin coating second photoresist on described second electrode and substrate;
Single-wall carbon tube is placed on described second photoresist, uses sem observation single-wall carbon tube pattern, select the single-wall carbon tube be suspended on described second electrode, and record its position and direction;
The substrate of described second electrode both sides forms the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed in described first electrode by described first electrode, the material of described first electrode is metal material, for performing " reading " function, the material of described third electrode is metal material, for performing " wiping " function;
After the length of described single-wall carbon tube is enough to make it bending, the openend of described single-wall carbon tube and described second electrode contact.
Further, describedly in the substrate of described second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed on described first electrode and comprises by described first electrode:
Spin coating the 3rd photoresist on described single-wall carbon tube and the second photoresist;
Utilize direct electronic beam writing technology, the second photoresist and the 3rd photoresist is etched in described second electrode both sides respectively according to the second shape and size preset and the 3rd shape and size, forming station terrace structure on the substrate, the step surface structure of described second electrode side is by out exposed for the stiff end of described single-wall carbon tube, and the step surface structure of described second electrode opposite side and the openend of described single-wall carbon tube are apart from certain distance;
Deposition of first electrode metal material and third electrode metal material in described step surface structure, form the first electrode and third electrode after removing remaining described second photoresist and the 3rd photoresist.
Further, describedly in the substrate of described second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed on described first electrode and comprises by described first electrode:
Spin coating the 4th photoresist on described single-wall carbon tube and the second photoresist;
Utilize direct electronic beam writing technology, according to the second shape and size described second photoresist of etching and the 4th photoresist preset, form First terrace structure on the substrate, described First terrace structure is by out exposed for the stiff end of single-wall carbon tube;
Deposition of first electrode metal material in described First terrace structure, forms the first electrode after removing remaining described second photoresist and the 4th photoresist;
Spin coating the 5th photoresist on described substrate, the second electrode and single-wall carbon tube;
Utilize direct electronic beam writing technology, according to the 3rd shape and size etching preset apart from described 5th photoresist of described single-wall carbon tube openend certain distance, form second step face structure on the substrate;
Described second step face structure deposits third electrode metal material, after removing the 5th remaining photoresist, forms third electrode.
It is further, described that by single-wall carbon tube, the method be placed on the second photoresist comprises:
Dispersion single-wall carbon tube is in the solution dropped in above described second photoresist or by the structure obtained after the second photoresist described in spin coating and be placed in the lower air port that floating catalyst system grows carbon pipe, the single-wall carbon tube of generation is dropped on the second photoresist of this body structure surface.
Further, the material of described first photoresist, the second photoresist and the 3rd photoresist is polymethyl methacrylate or dimethyl silicone polymer, and the thickness of described first photoresist, the second photoresist and the 3rd photoresist is 30nm-200nm.
Further, the material of described 4th photoresist and the 5th photoresist is polymethyl methacrylate or dimethyl silicone polymer, and the thickness of described 4th photoresist and the 5th photoresist is 30nm-200nm.
Further, the position of described record and direction comprise the stiff end of single-wall carbon tube and openend relative to the position of alignment mark and angle.
Nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention provides and preparation method thereof, by arranging the first electrode and third electrode in substrate, and first the second electrode between electrode and third electrode, and the single-wall carbon tube that has been coated and fixed in the first electrode, the openend of described single-wall carbon tube is unsettled, described openend can touch the second electrode after single-wall carbon tube is bending, single-wall carbon tube and the second electrode are had and disconnects and contact two kinds of stable states, thus realize the storage of information, by the first electrode, second electrode and third electrode realize information " reading ", " write " and " wiping ", the energy of information " writing " and " wiping " is mainly stored as mechanical energy, reusable edible, the nonvolatile memory based on single-wall carbon tube is made to have size thus little, heating is few, energy consumption is low, storage speed is fast, with the feature that the life-span is long, thus improve the integrated level of integrated circuit and device.
Accompanying drawing explanation
In order to the technical scheme of exemplary embodiment of the present is clearly described, one is done to the accompanying drawing used required for describing in embodiment below and simply introduce.Obviously, the accompanying drawing introduced is the accompanying drawing of a part of embodiment that the present invention will describe, instead of whole accompanying drawings, for those of ordinary skill in the art, under the prerequisite not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the profile of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides when being in " 0 " state;
Fig. 2 is the stereogram of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides when being in " 0 " state;
Fig. 3 is the vertical view of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides when being in " 0 " state;
Fig. 4 is the Local map of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides part A when being in " 0 " state;
Fig. 5 is the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides profile when being in one state;
Fig. 6 is the Local map of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides part B when being in one state;
Single-wall carbon tube when Fig. 7 a is " 0 " state that is in of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides and the view of the second electrode;
Fig. 7 b is the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides single-wall carbon tube when being in one state and the view of the second electrode;
Fig. 8 is the flow chart of the preparation method of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention two provides;
Fig. 9 a-Fig. 9 m is profile corresponding to each step of the preparation method of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention two provides.
Embodiment
Carbon nano-tube is by the curling seamless nanotube of single or multiple lift graphite flake.1991, the cathode deposition that first outstanding Electronic Speculum expert professor S.Iijima of Japan's NEC Corporation basic research laboratories is formed graphite rod argon gas direct-current discharge has carried out careful hom ology, his negative carbon after arc discharge finds a kind of needle-like product, diameter is in the scope of 4 ~ 30nm, length is about 1 μm.These spicules are the hollow tubules purchased by the concentric cylinder surface cover of carbon atom hexagonal lattice, i.e. carbon nano-tube.The structure of carbon nano-tube and graphite-like seemingly, are that the carbon atom of sp2 hydridization forms according to hexagonal manner structure, wherein C-C bond distance 0.142nm, draw ratio about 100 ~ 1000.Carbon nano-tube is a kind of multifunctional material, has the performance of many excellences.In terms of mechanics, the tensile strength of carbon nano-tube reaches 50 ~ 200GPa, and be 100 times of steel, density but only has 1/6 of steel.In electricity, carbon nano-tube has conductor and semiconductor two class, and its conductivity is relevant with diameter and structure, and the two determines (n, m are integers) by chiral vector (n, m), when n-m is the integral multiple of 3, single-layer carbon nano-tube is metallicity, otherwise is semiconductive.In calorifics, carbon nano-tube has very high draw ratio, and most of heat is conducted vertically, the heat conductivity of cylindrical carbon nanotube in direction of paralleling to the axis and diamond similar, and vertical direction is very low.
At present, being a hot fields about the ferromagnetic research of carbon-based material, is also the research topic that a dispute is larger.Three kinds of methods are generally had: 1. magnetic force microscopy (Magnetic Force Microscope is called for short MFM), the method can measure the magnetic moment of local in existing report.But the size of pattern on power being long range force and needle point due to magnetic force also has impact, thus current spatial resolution is probably in 20 nanometers.2.X ray Magnetic circular dichroism spectrum (X-ray Magnetic Circular Dichroism is called for short XMCD) is a kind of strong method, and it can judge to have spatial resolution about 50 nanometer to magnetic source and element.3. hysteresis measurement method is traditional, the most the most frequently used ferromagnetism research method, but sample must have maroscopic quantity can not measure by local area magnetic moment, and cannot get rid of ferromagnetism magazine if iron-cobalt-nickel is on the ferromagnetic impact of carbon back.
Inventor make use of a kind of the most ancient be also most effective method to study the local ferromagnetism of carbon-based material: ferromagnet is to the attraction phenomenon of iron filings.By research ferromagnetic metal atom, paramagnetic metal atom and diamagnetism metallic atom at the distinct Assembling Behavior of graphene edge, propose and prove that graphene edge has intrinsic magnetic moment.Form by Graphene is curling because carbon nano-tube can be regarded as, the carbon nano-tube of opening also should have intrinsic magnetic moment at openend.In nearest experimentation, inventor successfully demonstrates opening carbon nano-tube and has magnetic moment at opening part, and carried out testing estimation to the size of magnetic moment, inventor is referred to as the huge magnetic moment (GMM, giant magnetic moment) of openend.The huge magnetic moment that nonvolatile memory based on single-wall carbon tube provided by the invention make use of single-wall carbon tube openend just realizes the storage of information, the nonvolatile memory based on single-wall carbon tube is had size is little, heating less, energy consumption is low, storage speed is fast and the life-span is grown feature.
Below with reference to the accompanying drawing in the embodiment of the present invention, by embodiment, technical scheme of the present invention is intactly described.Obviously; described embodiment is a part of embodiment of the present invention, instead of whole embodiments, based on embodiments of the invention; the every other embodiment that those of ordinary skill in the art obtain under the prerequisite not making creative work, all falls within protection scope of the present invention.
Embodiment one:
Fig. 1 is the profile of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides when being in " 0 " state; Fig. 2 is the stereogram of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides when being in " 0 " state; Fig. 3 is the vertical view of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides when being in " 0 " state.
As shown in Figure 1-Figure 3, the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides, comprising: substrate 1; The material being formed at the first electrode 3, first electrode 3 in substrate 1 is metal material, for performing " reading " function; The material being formed at the second electrode 4, second electrode 4 in substrate 1 is ferrimagnet, for performing " writing " function; Be formed at the third electrode 5 in substrate 1, the material of third electrode 5 is metal material, for performing " wiping " function; Single-wall carbon tube 6, the stiff end 61 of single-wall carbon tube 6 is fixed in the first electrode 3, the unsettled side on the second electrode 4 of openend 62 of single-wall carbon tube 6; Second electrode 4 is between the first electrode 3 and third electrode 5, and after the length of single-wall carbon tube 6 is enough to make it bending, the openend 62 of single-wall carbon tube 6 contacts with the second electrode 4.
Preferably, the material of substrate 1 is nonmetallic materials or nonmetal oxide material, and the surface of substrate 1 has insulating barrier 2, and the material of described substrate is Si or SiO
2, the material of described insulating barrier comprises SiO
2, Al
2o
3or HfO
2in the composition of any one or at least two kinds.
Preferably, the thickness of described first electrode 3 is greater than the height of single-wall carbon tube 6 apart from substrate 1, is coated on by single-wall carbon tube 6 in first electrode 3, except electric action, can also fix single-wall carbon tube 6 better.
The metal material of described first electrode 3 and the metal material of third electrode 5 can be the composition of any one or at least two kinds in Au, Ag, Cu, W, Ti, Pt, Fe, Co or Ni, the described metal material of the first electrode 3 and the metal material of third electrode 5 can be the same or different, and the ferrimagnet of described second electrode 4 can be Fe, Co, Ni or ferrimag.
Described single-wall carbon tube 6 can be single single-wall carbon tube or single-wall carbon tube film.
In the present embodiment, described first electrode 3, second electrode 4 does not contact each other with third electrode 5 three, and the second electrode 4 thickness is less than the thickness of the first electrode 3 and third electrode 5.
Below in conjunction with Fig. 4-Fig. 6 and Fig. 7 a and Fig. 7 b, the course of work of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides and principle are specifically described.
Based on the mechanical characteristic of the thickness of the thickness of the first suitable electrode 3, the second electrode 4, the thickness of third electrode 5, length that single-wall carbon tube 6 stretches out and single-wall carbon tube 6, gap is there is between the openend 62 of single-wall carbon tube 6 and the second electrode 4, be not in contact with each other mutually, as shown in Figure 4, Fig. 4 is the Local map of the nonvolatile memory that the embodiment of the present invention one provides part A when being in " 0 " state.Now, because single-wall carbon tube 6 does not contact with the second electrode 4, the circuit formed between the first electrode 3, second electrode 4 is high resistance state, therefore memory presents high resistance state, this state can be denoted as " 0 " state, and therefore, the state in Fig. 1-Fig. 4 is " 0 " state.Be applied to the voltage that 3 one, the first electrode is less, such as: 1mV, can readout memory information.
Fig. 5 is the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides profile when being in one state.
The part identical with Fig. 1-Fig. 4 does not repeat them here.Apply an applied voltage on the second electrode 4, such as: 10mV, the openend 62 of single-wall carbon tube 6 and the second electrode 4 are respectively with the electric charge of opposed polarity, under the effect of electric field force, the extension of single-wall carbon tube 6 produces bending, the openend 62 of single-wall carbon tube 6 is contacted with the second electrode 4, and, because the openend 62 of single-wall carbon tube 6 has intrinsic magnetic moment, the stable state that still can keep in touch after removing voltage, as shown in Figure 6, Fig. 6 is the Local map of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides part B when being in one state.After applied voltage is removed, single-wall carbon tube 6 extension is subject to magnetic attraction and elastic restoring force, and based on the suitable flying height of single-wall carbon tube 6 and the length of extension, single-wall carbon tube 6 and the second electrode 4 keep in touch state, enter stable state.The circuit now formed between the first electrode 3 and the second electrode 4 is low resistance state, therefore memory presents low resistance state, this state can be denoted as one state, therefore, state in Fig. 5, Fig. 6 is one state, now can by described for data write based in the nonvolatile memory of single-wall carbon tube.
The described nonvolatile memory based on single-wall carbon tube is by applying an external voltage between the first electrode 3 and the second electrode 4 to the reading of information or write.To realize write or the reading of the nonvolatile memory state information of single-wall carbon tube with this by changing the size of external voltage.Judge that the circuit between the first electrode 3 and the second electrode 4 is in high resistance state or low resistance state by the size of electric current, with judge that memory is in " 0 " state or one state.
When information is written, if the external voltage that applying one is larger between the first electrode 3 and the second electrode 4, the circuit then formed between the first electrode 3 and the second electrode 4 is in low resistance state, the described write of the nonvolatile memory based on single-wall carbon tube one state, refer to Fig. 7 b, Fig. 7 b is the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides single-wall carbon tube when being in one state and the view of the second electrode, wherein, thicker electrode represents the second electrode 4, and thinner electrode represents single-wall carbon tube 6; If do not add applying external voltage between the first electrode 3 and the second electrode 4, what then form circuit between the first electrode 3 and the second electrode 4 is in high resistance state, the described nonvolatile memory based on single-wall carbon tube writes " 0 " state, refer to Fig. 7 a, single-wall carbon tube when Fig. 7 a is " 0 " state that is in of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention one provides and the view of the second electrode, wherein, thicker electrode represents the second electrode 4, and thinner electrode represents single-wall carbon tube 6.
When reading information, the external voltage that applying one is less between the first electrode 3 and the second electrode 4, if the electric current forming circuit between the first electrode 3 and the second electrode 4 is less, what form circuit between the first electrode 3 and the second electrode 4 is in high resistance state, and the described nonvolatile memory based on single-wall carbon tube reads " 0 " state; If the electric current forming circuit between the first electrode 3 and the second electrode 4 is comparatively large, what form circuit between the first electrode 3 and the second electrode 4 is in low resistance state, and the described nonvolatile memory based on single-wall carbon tube reads one state.
When the external voltage that applying one on third electrode 5 is suitable, the single-wall carbon tube 6 being in the nonvolatile memory based on single-wall carbon tube of one state can be subject to the attraction of third electrode 5, when attraction is enough to the polarity overcoming the second electrode 4 pairs of single-wall carbon tubes 6, the openend 62 of single-wall carbon tube 6 will leave the second electrode 4, make to there is gap between the openend 62 of single-wall carbon tube 6 and the second electrode 4, do not contact mutually, as shown in Figure 4, thus the state of memory gets back to " 0 " state from one state, realizes erase feature.
Embodiment two
Fig. 8 is the flow chart of the preparation method of the nonvolatile memory that the embodiment of the present invention two provides.Fig. 9 a-Fig. 9 m is profile corresponding to each step of the preparation method of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention two provides.
Be described in detail below in conjunction with the preparation method of Fig. 8 and Fig. 9 a-Fig. 9 m to the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention two provides.It should be noted that, the embodiment of the present invention two only gives the preparation method of the nonvolatile memory based on single-wall carbon tube described in embodiment one, those of ordinary skill in the art are under the prerequisite not making creative work, based on the present embodiment two, the embodiment of the preparation method of the nonvolatile memory based on single-wall carbon tube of other structures can be obtained.
The preparation method of the nonvolatile memory based on single-wall carbon tube that the embodiment of the present invention two provides, comprises the following steps:
Step S1, in substrate spin coating first photoresist.
As illustrated in fig. 9, spin coating first photoresist 71 on the base 1, preferably, the material of described substrate 1 is nonmetallic materials or nonmetal oxide material, and the surface of described substrate 1 has insulating barrier 2, and the material of described substrate 2 is Si or SiO
2, described insulating barrier 2 is SiO
2, Al
2o
3or HfO
2in the composition of any one or at least two kinds.
Step S2, utilize direct electronic beam writing technology, the first shape and size according to presetting etch the first photoresist, deposited iron magnetic material, form the second electrode after removing the first photoresist.
As shown in figure 9b, on the first photoresist 71, needed the region of exposure by electron beam irradiation according to the first shape and size preset, the strand of place first photoresist 71 of illuminated mistake can be interrupted, again the first photoresist 71 after exposure is put into inside developer solution and develops, will be washed off by the first photoresist 71 interrupting strand, other local not impacts, the ferrimagnet of the first photoresist after development and substrate surface evaporation second electrode again, and then remove the first photoresist with acetone, the ferrimagnet of second electrode on the first photoresist surface is removed together along with the first photoresist, form the second electrode 4, described ferrimagnet is preferably Fe, Co, Ni or ferrimag.
Step S3, on the second electrode and substrate spin coating second photoresist.
As is shown in fig. 9 c, spin coating second photoresist 72 on the second electrode 4 and substrate 1, the material that described first photoresist 71 and the second photoresist 72 are is preferably polymethyl methacrylate (Poly Methyl Meth Acrylate, be abbreviated as PMMA) or dimethyl silicone polymer (Poly Di Methyl Siloxane, be abbreviated as PDMS), described first photoresist 71 and the second photoresist 72 thickness are preferably 30nm-200nm, preferred, the thickness of described first photoresist 71 and the second photoresist 72 is 80nm.
Step S4, single-wall carbon tube is placed on the second photoresist, uses sem observation single-wall carbon tube pattern, select the single-wall carbon tube be suspended on the second electrode, and record its position and direction.
As shown in figure 9d, single-wall carbon tube 6 is placed on the second photoresist 72, uses sem observation single-wall carbon tube 6 pattern, select the single-wall carbon tube 6 be suspended on the second electrode 4, and record its position and direction.After the length of described single-wall carbon tube 6 is enough to make it bending, the openend 62 of described single-wall carbon tube 6 can touch described second electrode 4; Preferably, described by single-wall carbon tube 6, the method be placed on the second photoresist 72 comprises the lower air port dropping in above the second photoresist 72 by dispersion single-wall carbon tube 6 in the solution or the structure obtained after spin coating second photoresist 72 is placed in floating catalyst system growth carbon pipe, makes the single-wall carbon tube 6 of generation drop on the second photoresist 72 of this body structure surface; Described single-wall carbon tube 6 is preferably single single-wall carbon tube or single-wall carbon tube film; The preparation method of described single-wall carbon tube 6 comprises chemical vapour deposition technique, arc discharge method or Laser vaporization; The position of described record comprises the stiff end 61 of single-wall carbon tube 6 and openend 62 relative to the position of alignment mark and angle; The flying height of described single-wall carbon tube 6 can be regulated and controled by the thickness of the second photoresist 72 of spin coating.
Step S5, in the substrate of the second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed in described first electrode by described first electrode, the material of described first electrode is metal material, for performing " reading " function, the material of described third electrode is metal material, for performing " wiping " function.
Preferably, describedly in the substrate of the second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed in described first electrode and realizes by following step by described first electrode:
Step S51, on described single-wall carbon tube and the second photoresist spin coating the 3rd photoresist.
As shown in figure 9e, on single-wall carbon tube 6 and the second photoresist 7, the material of spin coating the 3rd photoresist the 73, three photoresist 73 is preferably PMMA or PDMS, and the 3rd photoresist 73 thickness is preferably 30nm-200nm, preferred, and the thickness of the 3rd photoresist 73 is 200nm.
Step S52, utilize direct electronic beam writing technology, the second photoresist and the 3rd photoresist is etched in the second electrode both sides respectively according to the second shape and size preset and the 3rd shape and size, forming station terrace structure in substrate, the step surface structure of described second electrode side is by out exposed for the stiff end of single-wall carbon tube, and the step surface structure of described second electrode opposite side and the openend of described single-wall carbon tube are apart from certain distance.
As shown in figure 9f, utilize direct electronic beam writing technology, expose in the second electrode both sides respectively according to the second shape and size preset and the 3rd shape and size, after development in the substrate 1 of the second electrode 4 both sides forming station terrace structure, wherein, the step surface structure of described second electrode side is by out exposed for the stiff end 61 of single-wall carbon tube 6, and the step surface structure of described second electrode opposite side and the openend 62 of described single-wall carbon tube are apart from certain distance.
Step S53, in described step surface structure deposition of first electrode metal material and third electrode metal material, form the first electrode and third electrode after removing remaining described second photoresist and the 3rd photoresist.
As shown in figure 9g, evaporation first electrode matel material and third electrode metal material in the step surface structure that step S52 is formed, described first electrode matel material is identical with third electrode metal material, form the first electrode 3 and third electrode 5, preferably, described first electrode matel material and third electrode metal material are Au, Ag, Cu, W, Ti, Pt, Fe, the composition of any one or at least two kinds in Co or Ni, the thickness of described first electrode 3 and third electrode 5 can be regulated and controled by the thickness of the first electrode matel material of deposition and the 3rd metal material, preferably, the thickness of described first electrode 3 and described third electrode 5 is 100nm.
Due in the process of evaporation first electrode matel material and third electrode metal material, can by the metal material of the metal material of evaporation one deck first electrode or third electrode on the 3rd photoresist 73 remaining on second photoresist 72 of remnants on the second electrode 4 and single-wall carbon tube 6, acetone can be used to remove the 3rd photoresist 73 remaining on the second photoresist 72 remaining on the second electrode 4 and single-wall carbon tube 6, now being positioned at the metal material of the first electrode on the second remaining photoresist and the 3rd photoresist or the metal material of third electrode along with second photoresist of remnants and the 3rd photoresist is together removed, thus form the first electrode and third electrode, obtain the nonvolatile memory based on single-wall carbon tube as shown in figure 9g.
Preferably, describedly in the substrate of the second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed in described first electrode and realizes by following step by described first electrode:
Step S51a, on single-wall carbon tube and the second photoresist spin coating the 4th photoresist.
As shown in Fig. 9 h, spin coating the 4th photoresist 74 on single-wall carbon tube 6 and the second photoresist 72, the material of described 4th photoresist 74 is preferably PMMA glue or PDMS glue, and described 4th photoresist 74 thickness is 30nm-200nm, preferred, the thickness of described 4th photoresist 74 is 200nm.
Step S52b, utilize direct electronic beam writing technology, the second shape and size according to presetting etch the second photoresist and the 4th photoresist, and substrate is formed First terrace structure, and described First terrace structure is by out exposed for the stiff end of single-wall carbon tube.
As illustrated in fig. 9i, utilize direct electronic beam writing technology, the second shape and size according to presetting expose the second photoresist 72 and the 4th photoresist 74, and form First terrace structure after development, described First terrace structure is by out exposed for the stiff end 61 of single-wall carbon tube 6.
Step S53c, in First terrace structure deposition of first electrode metal material, form the first electrode after removing remaining described second photoresist and the 4th photoresist.
As shown in Fig. 9 j, evaporation first electrode matel material in First terrace structure, now, also by the metal material of the first electrode on evaporation on second photoresist 72 and the 4th photoresist 74 of remnants, acetone can be used to remove the second remaining photoresist 72 and the 4th photoresist 74, now, the metal material being positioned at the first electrode on the second remaining photoresist 72 and the 4th photoresist 74 is also removed, thus form the first electrode 3, preferably, described first electrode matel material is Au, Ag, Cu, W, Ti, Pt, Fe, the composition of any one or at least two kinds in Co or Ni, the thickness of described first electrode 3 can be regulated and controled by the thickness of the first electrode matel material of deposition, preferably, the thickness of described first electrode 3 is 100nm.
Preferably, the thickness of the first electrode matel material of described deposition is greater than the height of single-wall carbon tube 6 apart from substrate 1, make the first electrode 3 be coated in the first electrode 3 completely by the stiff end 61 of single-wall carbon tube 6, except electric action, single-wall carbon tube 6 can also be fixed better.
Step S54d, on described substrate, the second electrode and single-wall carbon tube spin coating the 5th photoresist.
As shown in Fig. 9 k, after removing the second remaining photoresist 72 and the 4th photoresist 74, expose the second electrode 4 in substrate and substrate 1 and openend and be suspended on single-wall carbon tube 6 above the second electrode 4, spin coating the 5th photoresist 75 on described substrate 1, second electrode 4 and single-wall carbon tube, preferably, the material of described 5th photoresist 75 is preferably PMMA glue or PDMS glue, and described 5th photoresist 75 thickness is 30nm-200nm.
Step S55e, utilize direct electronic beam writing technology, according to described 5th photoresist of the 3rd shape and size etching distance single-wall carbon tube openend certain distance preset, form second step face structure on the substrate.
As shown in Fig. 9 l, utilize direct electronic beam writing technology, expose according to adjust the distance the 5th photoresist 75 of openend 62 certain distance of single-wall carbon tube 6 of the 3rd shape and size preset, in substrate, after development, form second step face structure.
Step S56f, in the structure of described second step face, deposit third electrode metal material, after removing the 5th remaining photoresist, form third electrode.
As shown in fig. 9m, evaporation third electrode metal material in the structure of second step face, now, 5th photoresist of remnants can form one deck third electrode metal material simultaneously, acetone can be used to remove the 5th photoresist of described remnants, the third electrode metal material be positioned on the 5th remaining photoresist is together removed, thus form third electrode 5, described third electrode metal material is different from described first electrode matel material, preferably, described third electrode metal material is Au, Ag, Cu, W, Ti, Pt, Fe, the composition of any one or at least two kinds in Co or Ni, the thickness of described third electrode 5 can be regulated and controled by the thickness of the third electrode metal material of deposition, preferably, the thickness of described third electrode 5 is 100nm, obtain the nonvolatile storage based on single-wall carbon tube as shown in fig. 9m.
Nonvolatile memory based on single-wall carbon tube of the present invention has following advantage compared with existing memory:
Size is little: the diameter of single-wall carbon tube is very little (being about 1.5 nanometers), and the nonvolatile memory overall dimensions accordingly based on single-wall carbon tube is determined by the size of the first electrode, the second electrode and third electrode.
Energy consumption is little, heating is few: " writing ", " wiping " energy based on the nonvolatile memory information of single-wall carbon tube is mainly stored as mechanical energy, reusable edible, and " reading " voltage is little, and heating is few.
Speed is fast, the life-span is long: have good electricity and mechanical characteristic based on single-wall carbon tube, such that the store status based on the nonvolatile memory of single-wall carbon tube is stable, storage speed fast, and long service life.
The present invention by arranging the first electrode and third electrode in substrate, and first the second electrode between electrode and third electrode, and the single-wall carbon tube that has been coated and fixed in the first electrode, the openend of described single-wall carbon tube is unsettled, described openend can touch the second electrode after single-wall carbon tube is bending, by utilizing the huge magnetic moment of single-wall carbon tube openend, single-wall carbon tube and the second electrode is made to have disconnection and the stable state of contactee two kinds, thus realize the storage of information, by the first electrode, second electrode and third electrode realize information " reading ", " write " and " wiping ", the energy of information " writing " and " wiping " is mainly stored as mechanical energy, reusable edible, the nonvolatile memory based on single-wall carbon tube is made to have size thus little, heating is few, energy consumption is low, storage speed is fast, with the feature that the life-span is long, thus improve the integrated level of integrated circuit and device.
The know-why that above are only preferred embodiment of the present invention and use.The invention is not restricted to specific embodiment described here, the various significant changes can carried out for a person skilled in the art, readjust and substitute all can not depart from protection scope of the present invention.Therefore, although be described in further detail invention has been by above embodiment, the present invention is not limited only to above embodiment, when not departing from the present invention's design, can also comprise other Equivalent embodiments more, and scope of the present invention is determined by the scope of claim.
Claims (12)
1. based on a nonvolatile memory for single-wall carbon tube, it is characterized in that, comprising:
Substrate;
First electrode, is formed in described substrate, and the material of described first electrode is metal material, for performing " reading " function;
Second electrode, is formed in described substrate, and the material of described second electrode is ferrimagnet, for performing " writing " function;
Third electrode, is formed in described substrate, and the material of described third electrode is metal material, for performing " wiping " function;
Single-wall carbon tube, the stiff end of described single-wall carbon tube is fixed in described first electrode, and the openend of described single-wall carbon tube is suspended on above described second electrode;
Described second electrode between described first electrode and third electrode, after the length of described single-wall carbon tube is enough to make it bending, the openend of described single-wall carbon tube and described second electrode contact.
2. the nonvolatile memory based on single-wall carbon tube according to claim 1, is characterized in that, the thickness of described first electrode is greater than the height of described single-wall carbon tube apart from described substrate.
3. the nonvolatile memory based on single-wall carbon tube according to claim 1, is characterized in that, the material of described substrate is nonmetallic materials or nonmetal oxide material, and the surface of described substrate has insulating barrier, and wherein, the material of described substrate is Si or SiO
2, the material of described insulating barrier comprises SiO
2, Al
2o
3or HfO
2in the composition of any one or at least two kinds.
4. the nonvolatile memory based on single-wall carbon tube according to claim 1, it is characterized in that, the metal material of described first electrode and the metal material of described third electrode are the composition of any one or at least two kinds in Au, Ag, Cu, W, Ti, Pt, Fe, Co or Ni, and described ferrimagnet is Fe, Co, Ni or ferrimag.
5. the nonvolatile memory based on single-wall carbon tube according to claim 1, is characterized in that, described single-wall carbon tube is single single-wall carbon tube or single-wall carbon tube film.
6. based on a preparation method for the nonvolatile memory of single-wall carbon tube, it is characterized in that, comprise the following steps:
Spin coating first photoresist in substrate;
Utilize direct electronic beam writing technology, the first shape and size according to presetting etch the first photoresist, deposited iron magnetic material, form the second electrode after removing described first photoresist;
Spin coating second photoresist on described second electrode and substrate;
Single-wall carbon tube is placed on described second photoresist, uses sem observation single-wall carbon tube pattern, select the single-wall carbon tube be suspended on described second electrode, and record its position and direction;
The substrate of described second electrode both sides forms the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed in described first electrode by described first electrode, the material of described first electrode is metal material, for performing " reading " function, the material of described third electrode is metal material, for performing " wiping " function;
After the length of described single-wall carbon tube is enough to make it bending, the openend of described single-wall carbon tube and described second electrode contact.
7. the preparation method of the nonvolatile memory based on single-wall carbon tube according to claim 6, it is characterized in that, describedly in the substrate of described second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed on described first electrode and comprises by described first electrode:
Spin coating the 3rd photoresist on described single-wall carbon tube and the second photoresist;
Utilize direct electronic beam writing technology, the second photoresist and the 3rd photoresist is etched in described second electrode both sides respectively according to the second shape and size preset and the 3rd shape and size, forming station terrace structure on the substrate, the step surface structure of described second electrode side is by out exposed for the stiff end of described single-wall carbon tube, and the step surface structure of described second electrode opposite side and the openend of described single-wall carbon tube are apart from certain distance;
Deposition of first electrode metal material and third electrode metal material in described step surface structure, form the first electrode and third electrode after removing remaining described second photoresist and the 3rd photoresist.
8. the preparation method of the nonvolatile memory based on single-wall carbon tube according to claim 6, it is characterized in that, describedly in the substrate of described second electrode both sides, form the first electrode and third electrode respectively, the stiff end of single-wall carbon tube is fixed on described first electrode and comprises by described first electrode:
Spin coating the 4th photoresist on described single-wall carbon tube and the second photoresist;
Utilize direct electronic beam writing technology, according to the second shape and size described second photoresist of etching and the 4th photoresist preset, form First terrace structure on the substrate, described First terrace structure is by out exposed for the stiff end of single-wall carbon tube;
Deposition of first electrode metal material in described First terrace structure, forms the first electrode after removing remaining described second photoresist and the 4th photoresist;
Spin coating the 5th photoresist on described substrate, the second electrode and single-wall carbon tube;
Utilize direct electronic beam writing technology, according to the 3rd shape and size etching preset apart from described 5th photoresist of described single-wall carbon tube openend certain distance, form second step face structure on the substrate;
Described second step face structure deposits third electrode metal material, after removing the 5th remaining photoresist, forms third electrode.
9. the preparation method of the nonvolatile memory based on single-wall carbon tube according to claim 6, is characterized in that, described by single-wall carbon tube, the method be placed on the second photoresist comprises:
Dispersion single-wall carbon tube is in the solution dropped in above described second photoresist or by the structure obtained after the second photoresist described in spin coating and be placed in the lower air port that floating catalyst system grows carbon pipe, the single-wall carbon tube of generation is dropped on the second photoresist of this body structure surface.
10. the preparation method of the nonvolatile memory based on single-wall carbon tube according to claim 7, it is characterized in that, the material of described first photoresist, the second photoresist and the 3rd photoresist is polymethyl methacrylate or dimethyl silicone polymer, and the thickness of described first photoresist, the second photoresist and the 3rd photoresist is 30nm-200nm.
The preparation method of 11. nonvolatile memories based on single-wall carbon tube according to claim 8, it is characterized in that, the material of described 4th photoresist and the 5th photoresist is polymethyl methacrylate or dimethyl silicone polymer, and the thickness of described 4th photoresist and the 5th photoresist is 30nm-200nm.
The preparation method of 12. nonvolatile memories based on single-wall carbon tube according to claim 6, is characterized in that, the position of described record and direction comprise the stiff end of single-wall carbon tube and openend relative to the position of alignment mark and angle.
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