CN109935685A - A kind of method of controlled material Vacancy defect - Google Patents
A kind of method of controlled material Vacancy defect Download PDFInfo
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Abstract
The invention discloses a kind of methods of controlled material Vacancy defect, this method is to apply material by being inserted into stress into phase transition function material, to regulate and control the vacancy defect concentration in the phase transition function material, and thus obtain the composite construction that phase transition function material and stress application material chimeric growth generate；Its phase-change characteristic of the composite construction is mainly determined by the phase transition function material therein, variation is generated based on phase transition function material crystals its phase-change characteristic for making its phase-change characteristic of the composite construction to be obtained by the pure phase transition function material by the regulation that the stress applies material, and the stress applies the material that material is specially capable of forming crystalline state.The present invention applies material particularly by the slightly larger stress of constant is inserted into the smaller phase transition function material of lattice constant, and the concentration of phase-change storage material Vacancy defect can be effectively reduced, to reduce the threshold value of its crystallization process, effectively promote its crystallization rate.
Description
Technical field
The invention belongs to microelectronic material fields should more particularly, to a kind of method of controlled material Vacancy defect
Method can carry out active modulation to fault in material, more particularly to regulate and control to the vacancy defect in phase-change storage material.
Background technique
Phase-change storage material can be by applying electricity or light pulse quickly between low resistance state and high-impedance state due to it
It realizes reversible transformation and is paid close attention to by people, the process that high resistant is changed into low-resistance is known as SET process, and inverse process is known as
RESET process.Memory technology based on phase-change material is by it is believed that be one of the contenders of next-generation memory technology.Phase
Transition storage part is fast with erasable and writing speed, binary states difference is big and simultaneous with existing complementary metal oxide semiconductor (CMOS) technique
The advantages such as appearance.
The vacancy defect important as one of phase-change storage material is studied of interest by people always.At present its
Research method is divided into first principle simulation and calculates and test two major classes.Wherein, experimental method has angle of elevation annular dark field-scanning again
Transmission electron microscope (HAADF-STEM), Extended X-ray Absorption Fine Structure (EXAFS), positron annihilation spectrum (PILS), electricity
Son spin response spectra (EPR) etc..But currently used vacancy characterization method belongs to passively research method, that is, studies and all build
It stands after vacancy has been formed, effective laboratory facilities in active control vacancy are still deficienter at present.
Correlative study discovery, the presence or absence in vacancy greatly affected the characteristic of phase-change material.On the one hand, vacancy is deposited
In the energy barrier for effectively reducing atomic migration, may play an important role in the power consumption for reducing phase-change material
(Deringer V L,Lumeij M,Stoffel R P,et al.Mechanisms of atomic motion through
crystalline GeTe[J].Chemistry of Materials,2013,25(11):2220-2226.).And another party
The presence in face, vacancy will form cavity during phase-change storage material is repeatedly erasable, lead to its performance failure, this may be
Limitation phase-change material recycle erasable ability a key factor (Njoroge W K, H W,Wuttig
M.Density changes upon crystallization of Ge2Sb2.04Te4.74films[J].Journal of
Vacuum Science&Technology A:Vacuum,Surfaces,and Films,2002,20(1):230-233.)。
Therefore, the implementation method of controllable vacancy concentration is developed as early as possible, and according to the performance to phase-change storage material
Differentiated demand actively promotes or inhibits the generation in vacancy, and then realizes modification to phase-change storage material to phase transition storage
It can improve and its industrialization is of great significance.
Summary of the invention
Aiming at the above defects or improvement requirements of the prior art, the purpose of the present invention is to provide a kind of controlled material is hollow
The method of position defect, this method is specifically that different crystalline lattice stress is realized using lattice mismatch degree, so that controlled material is hollow
Position defect density, specifically generates tensile stress or compression using the mismatch between two kinds of material lattice constants in the material,
Density is stacked to reduce or increase the atom of material accordingly, and then inhibits or promote the generation of material Vacancy defect.
Also, the present invention applies material particularly by the slightly larger stress of lattice constant is inserted into the smaller phase transition function material of lattice constant
Material, Lai Zeng great vacancy defect forms required energy, and then reduces the concentration of phase-change storage material Vacancy defect, to drop
The threshold value of its low crystallization process effectively promotes its crystallization rate.
To achieve the above object, according to one aspect of the present invention, it provides a kind of based on crystal lattice stress regulation phase transformation material
Expect the method for Vacancy defect density, which is characterized in that this method is to apply material by being inserted into stress into phase transition function material
Thus material to regulate and control the vacancy defect concentration in the phase transition function material, and obtains phase transition function material and stress application
The composite construction that material chimeric growth generates；Its phase-change characteristic of the composite construction is mainly determined by the phase transition function material therein
It is fixed, its phase-change characteristic of the composite construction is made to be obtained by the pure phase transition function material by the regulation that the stress applies material
Variation is generated based on phase transition function material crystals its phase-change characteristic arrived, and it is specially to be capable of forming that the stress, which applies material,
The material of crystalline state.
As present invention further optimization, when the phase transition function material and stress application material are simultaneously crystalline state
When, apply in the phase transition function material with the stress and is received outside the lattice that the interface that material has a common boundary has these two types of materials
Touching；
Also, material is applied for the phase transition function material and the stress, is obtained by the pure phase transition function material
To phase transition function material crystals with the stress that material obtains applied by the pure stress apply material crystals these two types crystal
Between lattice mismatch rate absolute value between 0.1% to 10%；
Preferably, its lattice constant of phase transition function material crystals obtained by the pure phase transition function material is less than by pure
The stress apply the obtained stress of material and apply its lattice constant of material crystals.
As present invention further optimization, the stress that is inserted into phase transition function material applies material specifically to institute
It states and is inserted into the stress applied layer that the stress applies material composition in the phase transition function layer of phase transition function material composition, thus obtain
The multi-layer film structure that phase transition function layer and stress applied layer alternating growth generate.
As present invention further optimization, the multi-layer film structure is periodic multi-layer film structure；The multilayer film knot
Any one period of structure includes simultaneously a phase transition function layer and a stress applied layer, wherein the phase transition function layer and
The ratio between the thickness of the stress applied layer meets 1:10~10:1；The thickness in any one period meets 2-10nm, entire described
Total periodicity of multi-layer film structure meets 5-100.
As present invention further optimization, for the multi-layer film structure, particular by the thickness for adjusting stress applied layer
It spends to adjust its size to the phase transition function ply stress, and then adjusts the formation energy of vacancy defect, to be formed different
Vacancy defect concentration.
As present invention further optimization, the phase transition function material does not contain Van der Waals gap between atomic layer
Microcosmic non-laminar phase-change material, the stress apply material and contain the microcosmic stratified material in Van der Waals gap between atomic layer；
Preferably, the phase transition function material is intrinsic or element doping pure metals or compound-material, wherein institute
Stating pure metals is Sb simple substance, and the compound-material is the compound that Ge and Te are formed, the compound that Ge and Sb are formed, Ge,
The compound that Sb, Te three are formed, the compound that the compound or Ge, Sb, Bi, Te that Ge, Bi, Te three are formed are formed；
The element of doping is at least one of C, Cu, N, O, Si, Sc, Ti；It is the chemical combination that Sb and Te is formed that the stress, which applies material,
The chemical combination that the compound or Mo and S that the compound that the compound that object, Bi and Te are formed, Ge and Se are formed, In and Se are formed are formed
Object；
It is furthermore preferred that the phase transition function material is GeTe, GeSb, Ge2Sb2Te5Or Ge1Sb2Te4；The stress applies
Material is Sb2Te3Or Bi2Te3。
It is another aspect of this invention to provide that regulating and controlling phase-change material based on crystal lattice stress using above-mentioned the present invention provides a kind of
The corresponding obtained composite construction of the method for Vacancy defect density, which is characterized in that in the composite construction phase transition function material with
Stress applies the chimeric distribution of material.
As present invention further optimization, it is crystalline state that the stress, which applies material,.
Another aspect according to the invention, the present invention provides a kind of phase transition storages using above-mentioned composite construction.
It is another aspect of this invention to provide that the present invention provides the methods for preparing above-mentioned composite construction, which is characterized in that should
Preparation method is specifically to be based on magnetron sputtering method, molecular-layer deposition method, molecular beam epitaxy, pulsed laser deposition, physics gas
Mutually deposition, chemical vapor deposition method, thermal evaporation or electrochemical growing method.
Contemplated above technical scheme through the invention, compared with prior art, due to being inserted into phase transition function material
Enter stress and apply material, the regulation to phase transition function material stress is realized, thus in phase transition function material described in final regulation and control
Vacancy defect concentration.Also, based on the method for regulating and controlling vacancy concentration in the present invention by realization different crystalline lattice stress, Ke Yitong
It overregulates phase transition function material and stress applies the ratio of material, the formation for adjusting vacancy defect can be so that form different vacancy
Concentration.
Phase transition function material and stress, which apply lattice constant mismatch rate between material, should not be too large, lattice mismatch in the present invention
Rate δ is defined as:
Wherein, b is that stress applies lattice constant in the face of material, and a is lattice constant in the face of phase transition function material.Two kinds
The absolute value of lattice mismatch rate between material is preferably between 0.1% to 10%, to guarantee the extension coupling between two kinds of lattices
Conjunction is easier to occur, to guarantee that phase transition function material and stress apply material, both materials should have lattice in interface
The contact (that is, two kinds of materials are entrenched togather) of extension class, rather than it is all crystal boundary contact.
For phase transition function layer material and stress to be applied to layer material alternating growth and are stress multi-layer film structure, the structure
For the multi-layer film structure for using lattice constant different and at least two class materials of alternating growth obtain；Note phase transition function layer is that A (should
Layer simultaneously be stress receiving layer), stress applied layer be B, the present invention is preferably compounded to form periodic stress multi-layer film structure；
Also, for the periodic structure, the thickness of preferable (A+B) layer is can be controlled between 2-10nm, (A+B) layer duplicate period
Number is can be controlled between 5-100, wherein at one (A+B) in the period, described A layers can be controlled in 1:10 with B layers of thickness proportion
To between 10:1.Its size to A ply stress can be adjusted by adjusting B layers of the thickness, and then adjusts vacancy defect
Formation can be to forming different vacancy concentrations.
Present invention preferably employs microcosmic non-laminar phase-change materials as phase transition function material (microcosmic non-laminar phase-change material
Its material microstructure belongs to non-laminar structure, that is, Van der Waals gap is not contained between atomic layer), using microcosmic stratified material
Applying material as stress, (its material microstructure of the microcosmic stratified material belongs to layer structure, that is, contains between part of atoms layer
Have Van der Waals gap), compared with microcosmic stratified material, its suffered stress of microcosmic non-laminar phase-change material is not easy to relaxation；And with
Microcosmic non-laminar material compared to microcosmic stratified material since Van der Waals gap stress suffered by it is easy relaxation, to be conducive to keep
Lattice constant is constant, and then can provide stable stress.
Method in the present invention can be applied to regulate and control phase transition function layer vacancy concentration in phase transition storage, and then realizes and change
The application of property purpose；For example, multi-layer film structure can be applied in phase transition storage to regulate and control phase transition function layer vacancy concentration,
And then realize the application of modified purpose.Its phase transition function of gained composite construction of the invention is mainly determined by phase transition function material therein
Fixed, stress therein applies material and only plays regulating and controlling effect；By taking multi-layer film structure as an example, it is preferred that stress applied layer is selecting
When material can phase transformation easier than phase transition function layer, be initially formed crystal phase (for example, stress apply its phase transition temperature of material can be lower than phase
Become functional layer phase transition temperature；That is, stress, which applies material, can be crystalline state, Huo Zhewei in present invention gained composite construction
Amorphous state, but it is crystalline state that it, which understands preferential conversion compared to phase transition function material, during phase transformation), thus in phase transition function
Stress is applied to it by Lattice Matching when layer phase transformation, to change the concentration of defect in phase transition function layer.
In addition, phase transition function layer material and stress are applied layer material alternating growth as stress multi-layer film structure, stress
Apply its lattice constant of layer material to be greater than in the face of functional layer material for lattice constant, be lost using the lattice between two kinds of materials
It matches phase transition function layer material and applies tensile stress, to increase the formation energy in vacancy, reduce the concentration of phase-change material Vacancy, from
And improve the phase-change characteristic of material and device.First-principles calculations show by apply tensile stress, functional layer Vacancy it is dense
Degree can be reduced to 1/the 1406 of original space position concentration.And the test result of X-ray diffraction and transmission electron microscope proves, in reality
Production in, this stress can first be deposited by plural layers after annealing generation.By applying tensile stress, phase-change material GeTe
SET speed can be speeded from 58ns to 12ns.Since the read or write speed of phase transition storage mainly determines that this is answered by SET speed
The method in power regulation vacancy will effectively improve the read or write speed of phase transition storage, while reduce the function of phase transition storage SET process
Consumption, and significance is generated to its following Industrialization.
To sum up, the present invention can obtain it is following the utility model has the advantages that
The producing method of different size of stress is simple and easy to do in the present invention, technical maturity, is easy to add with existing micro-nano
Work technique is mutually compatible with.And the size control of stress is flexible, is easy to implement the active control to material Vacancy concentration.To phase
Its vacancy concentration can be effectively reduced by becoming functional layer application tensile stress, to be greatly improved the speed of its SET process.For into one
The erasable and writing speed that step promotes phase transition storage provides another solution.
Regulate and control compared with research method with existing vacancy with two o'clock clear superiority: (1) regulation of the present invention
The active control to vacancy concentration may be implemented in the method for vacancy concentration.(2) regulate and control introduced stress applied layer and (be abbreviated as B
Layer) it is located at except phase transition function layer (being abbreviated as A layers), it is played a role by crystal boundary without entering A layers, and described B layers
Regulating and controlling effect is played to phase transition process, phase transition process is still mainly determined by A layer material (that is, obtained composite construction
Its phase-change characteristic is based on phase transition function material crystals its phase-change characteristic obtained by pure phase transition function material, by answering
The regulation that power applies material makes the phase-change characteristic of composite construction generate some slight changes), it was studied to significantly simplify
Journey.The invention enables the research to phase-change material Vacancy, more convenient and result is easier to analyze.
Increase the lattice constant of material using tensile stress, to reduce vacancy concentration, and then reduces the SET mistake of phase-change material
The threshold value of journey has finally speeded the SET operation speed of phase transition storage.The method of the stress regulation and control will be raising phase transition storage
Erasable and writing speed provides new thinking.
Detailed description of the invention
Fig. 1 is the side structure schematic diagram of heretofore described phase transformation multi-layer film structure.
Fig. 2 is X-ray diffraction (XRD) test result of heretofore described phase transformation multilayer film.
(a) is spherical aberration correction transmission electron microscope (ACTEM) test result of heretofore described phase transformation multilayer film in Fig. 3, (b)
It is the HAADF-TEM test result of phase transformation multilayer film interface.
The multilayer that (a) is heretofore described A thickness degree/B thickness degree in Fig. 4 when being respectively 1:0,1:1,1:2 and 1:3
Film lattice structure model (b) simulates calculated result for stress and vacancy concentration corresponding under different-thickness ratio.
Fig. 5 is a kind of preparation process schematic diagram of phase-change memory cell T-shape structure.
Fig. 6 is that the plural layers of different vacancy concentrations are prepared into the SET velocity test knot carried out after phase-change memory cell
Fruit.
The meaning of each appended drawing reference is as follows in figure: 1 is Si substrate, and 2a is thermally grown SiO2Layer, 2b is physical vapour deposition (PVD)
Insulating layer, 3 be stress applied layer, and 4 be phase transition function layer, and 5a is lower electrode, and 5b is top electrode.
Specific embodiment
In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.As long as in addition, technical characteristic involved in the various embodiments of the present invention described below
Not constituting a conflict with each other can be combined with each other.
The present invention provides a kind of using crystal lattice stress controlled material Vacancy defect density and realizes different crystalline lattice stress
Method, its object is to generate tensile stress or compression in the material using the mismatch between two kinds of material lattice constants,
Density is stacked to reduce or increase the atom of material accordingly, and then inhibits or promote the generation of material Vacancy defect.
This method can be based on existing magnetron sputtering method, molecular-layer deposition method, molecular beam epitaxy, pulsed laser deposition, physics
Vapor deposition, chemical vapor deposition method, thermal evaporation or electrochemical growing method are realized.
For example, its material structure is the multi-layer film structure of lattice constant difference and alternating growth.Wherein, two different thin
One layer is phase transition function layer A in film, while being stress receiving layer.Another layer is stress applied layer B, and stress applied layer is only to phase transformation
Process generates regulating and controlling effect, its phase-change characteristic of multi-layer film structure is mainly determined by phase transition function material therein.
The thickness of (A+B) layer should be between 2-10nm, and the periodicity of (A+B) layer should be between 5-100.It is preferred that
Ground, two kinds of materials of described A, B should have the contact of lattice extension class in interface, rather than be all crystal boundary contact.Therefore, institute
Stating lattice constant mismatch rate between A and B layer material should not be too large, to guarantee that the coupling between two kinds of lattices is easier to occur.It is preferred that
Ground, the lattice mismatch rate between two kinds of materials should be between 0.1% to 10%.
The present invention provides a kind of methods for generating different stress intensities, i.e., by regulate and control stress applied layer B thickness come
Different size of stress is generated to functional layer A.Preferably, in one cycle, described A layers should be with B layers of thickness proportion
Between 1:10 to 10:1.
The present invention provides there are the preparation methods of the plural layers of stress, be described in one kind magnetron sputtering method, point
Sublayer sedimentation, molecular beam epitaxy, pulsed laser deposition, physical vapour deposition (PVD), chemical vapor deposition, thermal evaporation and electrification
The methods of student's length.By taking pulsed laser deposition as an example, pulsed laser deposition is specifically as follows alternate rotation phase transition function
Material and stress apply target used in material, and the multilayer of phase transition function layer Yu stress applied layer alternating growth is formed on the substrate
Membrane structure；Each phase transition function layer can be swashed with the thickness of each stress applied layer by controlling the pulse beaten on corresponding target
Light number controls, and the periodicity of multilayer film is controlled by the periodicity that two kinds of targets are alternately rotated.
The producing method of different size of stress is simple and easy to do in the present invention, technical maturity, is easy to add with existing micro-nano
Work technique is mutually compatible with.And the size control of stress is flexible, is easy to implement the active control to material Vacancy concentration.To phase
Its vacancy concentration can be effectively reduced by becoming functional layer application tensile stress, to be greatly improved the speed of its SET process.For into one
The erasable and writing speed that step promotes phase transition storage provides another solution.
The following are embodiments:
Embodiment 1
The multi-layer phase change stress film structure prepared in the present embodiment is [AmBn]l, wherein m, n respectively represent the thickness of A, B
Degree, unit are defaulted as nm (nanometer), and l is the periodicity of multilayer film alternating growth.1/10 < m/n < 10/1, and 2 < m+n < 10,5 < l <
100, m, n is real number, and l is integer.In the present embodiment, A GeTe, B Sb2Te3, m/n is respectively 4/0,2/2,1.3/2.7,
1/3, l is 12.GeTe for no Van der Waals gap microcosmic non-laminar material.Sb2Te3For the microstructure layer containing Van der Waals gap
Shape material, and its crystallization temperature is lower than the crystallization temperature of GeTe, crystallization can occur prior to GeTe in phase transition process.Therefore
The crystallization characteristic (such as SET speed) of plural layers is mainly determined by the crystallization rate of slower GeTe.Sb2Te3Although crystallization
It does not play a decisive role, but GeTe can be applied by Lattice Matching during GeTe crystallization to the crystallization process of plural layers
Add stress, change GeTe layers of microstructure, is embodied in the vacancy defect concentration changed in GeTe layers.Multi-layer phase change stress
Film is made by pulse laser deposition, after promote it to be changed into crystalline state by anneal.Followed by XRD and TEM
Test is to probe into its internal stress.Finally different vacancy as caused by different stress is calculated using first principle simulation
Form the difference of vacancy concentration caused by energy institute energy.Specific implementation method is as follows:
As shown in Figure 1, choosing the Si piece (layer 1) of 500 μ m-thicks, (100) orientation, the silicon chip surface is via heat growth method
Form the SiO of 1 μ m-thick2Film (layer 2a).Why selection has SiO2The Si piece of layer is because of SiO2It, can for unformed shape
Stress is generated to prevent single crystal Si substrate to the multi-layer phase change film of subsequent deposition.Silicon wafer is then cut into 1cm × 1cm size
It is put into beaker, injects proper amount of acetone, be cleaned by ultrasonic 10 minutes.It is used washes of absolute alcohol 10 minutes after cleaning.Finally
It is cleaned ten minutes using deionized water, and spare with nitrogen gun drying.
(2) cleaned silicon wafer is attached on the heater of pulsed laser deposition system using double-sided adhesive, is by purity
99.99% GeTe and Sb2Te3Target is put into cavity.The zlasing mode of pulsed laser deposition system selects EGY NGR, energy
Size selects 250mJ.It (is quickly Sb in the present embodiment by stress applied layer 3 by laser bombardment target2Te3) and phase transition function
On layer 4 (being GeTe in the present embodiment) alternating deposit to silicon wafer.The thickness of every kind of material by the laser pulse number of bombardment target Lai
Control.To GeTe and Sb in this present embodiment2Te3Target, deposition rate parameter are as follows:
1. GeTe, laser energy: 250mJ, laser frequency: 5Hz, target-substrate distance: 78mm, rate 283pulse/nm.
②Sb2Te3, laser energy: 250mJ, laser frequency: 5Hz, target-substrate distance: 78mm, rate 167pulse/nm.
The laser scanning region of two kinds of targets is disposed as, scanning area: 15mm × 1mm, LASER SPECKLE size: 2.1mm,
1mm, LASER SPECKLE position initial offset: -3mm, 2mm, sweep speed: 1mm/s.
(3) film of the different component deposited being put into annealing furnace and is made annealing treatment, annealing temperature is 250 DEG C,
Soaking time is 1 hour, and heating, cooling rate is 10 DEG C/min.The purpose of annealing is that multi-layer phase change film is promoted to be changed into
Crystalline state, stress are generated because multilayer film is changed into the lattice mismatch after crystalline state.
(4) by the crystalline state GeTe/Sb of various ingredients2Te3Film is put into X-ray diffractometer and is tested, angle scanning model
It encloses are as follows: 5 ° -60 °, scanning speed is 5 °/min.Test results are shown in figure 2 by XRD.
(5) XRD test is only capable of reflecting the microcosmic object phase of material indirectly, therefore further using TEM to the microcosmic of multilayer film
Structure has carried out direct observation.In TEM observation, the present embodiment is with [(GeTe)4(Sb2Te3)4]12Phase transformation multi-layer film structure is
Example.Firstly, being divided into [(GeTe) to group4(Sb2Te3)4]12Phase transformation plural layers use focused ion beam carry out sample preparation, sample preparation
Preliminary observation is carried out to the crystal grain in multilayer film using ACTEM after success, as shown in (a) in Fig. 3.In order to further observe
Lattice coupling relationship between functional layer and stress applied layer, spy using HAADF-TEM between the interface two kinds of material lattices into
Observation is gone, as a result as shown in (b) in Fig. 3.
(6) first-principles calculations
Using Materials Studio software to the GeTe/Sb of different component2Te3Multi-layer film structure is modeled, lattice
Shown in (a) in model such as Fig. 4.Structure optimization is carried out using vasp software to obtain the important ginseng such as vacancy formation energy and its concentration
Shown in (b) in number, correlation calculation result such as Fig. 4.
Using first principle to GeTe and Sb2Te3After carrying out structure optimization respectively, lattice constant is in the face of GeTeAnd Sb2Te3Face in lattice constant beThe lattice mismatch rate of the two be 2.36% (that is, 100% ×
(4.33-4.23)/4.23).When the lattice epitaxial growth of the two together when, GeTe will receive tensile stress, and Sb2Te3It will receive
Compression.In the test result of XRD, diffraction maximum is all Sb substantially2Te3The direction (00z) diffraction maximum, illustrate preparation should
The crystal grain of plural layers has preferable spatial orientation.Sb2Te3For a kind of two-dimensional material, lattice structure is on the direction outside face
It is stacked with for five-layer structure, is Van der Waals gap between five-layer structure.If Sb2Te3By compression on direction in face
If, certainty is extended in the outside direction of face.And the test result of XRD exactly demonstrates this point.The original of XRD test
Reason is Bragg diffraction, it may be assumed that
2dsin θ=n λ (2)
Wherein d is interplanar distance, and θ is the angle of diffraction, and n is integer, and λ is X-ray wavelength.
And Sb2Te3Atom number of plies M in each five-layer structure is obtained by following formula:
In formula, interplanar distance of the d (00z) between different crystal faces can be in the hope of (00z) is institute by Bragg diffraction formula
Corresponding crystal face.
The result tested from XRD can be seen that M increasing and be gradually increased with GeTe component, illustrate Sb2Te3With
The suffered stress in its face that increases of GeTe component is gradually increased.I.e. GeTe is with Sb2Te3Reduction its suffered stress be gradually reduced,
With Sb2Te3Increase institute's tension stress of thickness increases.
In TEM test, from GeTe/Sb known to (a) in Fig. 32Te3The size of crystal grain is 10nm-11nm left in multilayer film
It is right.The partial size is considerably beyond single layer GeTe or Sb2Te3Thickness, illustrate GeTe and Sb2Te3It is common after epitaxial growth
A crystal grain (that is, the contact for foring lattice extension class) is constituted, from demonstrating the presence of stress on the other hand.To Fig. 3
In region in white rectangle frame in (a) amplify after obtain (b) in Fig. 3, and the atom level of (b) is differentiated in Fig. 3
The test result of rate is then further more intuitive to show this presence due to stress caused by lattice mismatch.
In the elastic limit of material, the relationship of stress and strain is defined by following formula:
σ=E ε (4)
Wherein, σ is stress, and E is Young's modulus, and ε is strain.Because stress and strain is directly proportional, and in the embodiment only
Pay close attention to the GeTe/Sb of different component2Te3The relative value of stress between film, so using with can simplify in this embodiment
The dependent variable size of GeTe lattice indicates the size of the stress suffered by it.
First-principles calculations show to work as GeTe/Sb2Te3Thickness ratio when not being 4/0,2/2,1.3/2.7,1/3, answer
Power applied layer Sb2Te3The lattice stretching strain caused by functional layer GeTe is respectively 0%, 0.84%, 1.3% and 1.51%.It draws
Strain stresstIt is defined by following formula:
In formula, a'GeTeTo be formed after multi-layer film structure by lattice constant in the face of the GeTe of tensile stress, aGeTeFor not by
Lattice constant in the face of the GeTe of tensile stress.
Next under different action of pulling stress, the formation energy in the vacancy Ge in GeTe is calculated.Ge vacancy formation energy by
Following formula, which calculates, to be obtained:
In formula, EfFor vacancy formation energy, EtotFor system gross energy, VGeTe is the GeTe with vacancy, niμiRespectively indicate band
The chemical potential of atom number and corresponding atom that the GeTe in vacancy loses.
Calculated result is as shown in the table:
Formation energy corresponding relationship of 1 tensile stress of table (being measured with straining) with the vacancy Ge
Further, Ge vacancy concentration caused by different Ge vacancy formation energy institute energy is calculated according to the following formula
N is total Ge lattice point number herein, and n is the lattice point number in the vacancy Ge, EvIt is by a Ge atom from intracell lattice point
On be moved to required energy on the lattice point of surface.kBFor Boltzmann constant.T is temperature.Likewise, only being closed in the embodiment
Infuse the GeTe/Sb of different component2Te3The relative value of the hollow site concentration of film.So for convenient for comparing, it herein can be with the smallest
Vacancy concentration value (GeTe/Sb2Te3Vacancy concentration value when=1nm/3nm) it is normalized for reference value.Different calculated results
It is as shown in the table:
Corresponding relationship of the tensile stress (being measured with straining) that table 2 obtains with Ge vacancy concentration
Embodiment 2
Multilayer stress film structure is prepared into phase change cells in the present embodiment and has carried out SET velocity test.Multilayer film
[AmBn]lMiddle A remains as GeTe, and B is still Sb2Te3, GeTe and Sb2Te3The ratio between thickness still are as follows: 4/0,2/2,1.3/2.7,
1/3, it is constant that periodicity is still fixed as 12.Multi-layer film structure phase change cells preparation process is as described below:
(1) it as shown in (a) in Fig. 5, is deposited on the substrate that layer 1 and layer 2a are formed first with the method for magnetron sputtering
5a layers of lower electrode, 5a layers are the inert electrode materials such as Pt, TiW, Ta.
(2) physical vapour deposition (PVD) (PECVD) method depositing insulating layer 2b on 5a layer is utilized, 2b layers are SiO2、SiC、
Al2O3Equal insulating materials.
(3) photoresist with 250nm diameter circular aperture is formed on insulating layer 2b using electron-beam exposure system (EBL)
Exposure mask.
(4) plasma etching technology (ICP) etching insulating layer 2b, the insulating layer 2b of aperture position is utilized to be exposed to outside,
Therefore it is etched away, the other parts of insulating layer 2b are photo-etched glue and cover therefore be not etched.Etching is until 2b layers are cut through cruelly
Until exposing lower electrode 5a.Using going glue to remove photoresist after the completion of etching, finally obtain as shown in (a) in Fig. 5 most
Whole effect.
(5) the rectangular pore structure for carving 100 μm of 100 μ m is covered on aperture using ultraviolet lithographic system.The square hole with
The circular aperture center alignment that ICP is etched.
(6) GeTe/Sb of 4 kinds of different stress is deposited using pulsed laser deposition system in square hole2Te3Multilayer film, tool
Body step is consistent with (2) step in embodiment 1.After the completion of multi-layer film structure deposition, using magnetic control sputtering system on multilayer film
Upper electrode layer 5b is deposited, upper electrode layer is similarly the inert electrode materials such as Pt, TiW, Ta.
(7) using the photoresist of stripping technology removal ultraviolet photolithographic, to eliminate the GeTe/ between different phase change cells
Sb2Te3Multilayer film and upper electrode layer 5b, so that being separated from each other between different phase change cells, in final effect picture such as Fig. 5
(b) shown in.
It is surveyed using 4 kind multilayer film phase change cells of the B1500a characteristic of semiconductor tester to prepared different stress
Examination, main test content are its SET speed, and test results are shown in figure 6.
Due to Sb2Te3Regulating and controlling effect (Sb only is generated to phase transition process2Te3For GeTe, SET speed is faster；
And when the two forms multilayer film composite construction, the SET process of multilayer film needs the two to reach crystallization state simultaneously
Can complete, so the SET speed of multilayer film is mainly determined by the slower GeTe of SET speed), only it is to provide tensile stress, so
The SET speed performance of different phase change cells is different mainly since GeTe is by caused by its Ge vacancy concentration difference after stress.
From fig. 6 it can be seen that when the vacancy Ge in i.e. GeTe is reduced, SET speed is increasingly when GeTe institute's tension stress increases
Fastly.Concrete outcome is as shown in the table:
3 tensile stress of table (being measured with straining) and phase change cells SET speed corresponding relationship
Since the read or write speed of phase transition storage is mainly determined by SET speed, so the present embodiment is to promotion phase change memory
The read or write speed and reduction power consumption of device are of great significance.
Above-described embodiment only by taking the structure of this plane superposing type of multi-layer film structure as an example, is inserted into phase transition function material
Stress, which applies material, to be designed using other shapes, for example, by using core-shell structure or accidental distributed inserted mode etc..
Other than the specific material used in above-described embodiment, phase transition function material can also be Sb simple substance in the present invention,
The compound that the compound that Ge and Te is formed, Ge and Sb are formed, the compound that Ge, Sb, Te are formed, the chemical combination that Ge, Bi, Te are formed
Object, the compound that Ge, Sb, Bi, Te are formed；The above compound can also be free group with doped chemical C, Cu, N, O, Si, Sc, Ti
It closes.Stress applies the compound that material can also be formed for Sb and Te, the compound that Bi and Te are formed, the chemical combination that Ge and Se are formed
The compound that the compound that object, In and Se are formed, Mo and S are formed.
In addition, in practical application, in the present invention based on crystal lattice stress regulation phase-change material Vacancy defect density
In method, stress can be formed by In Situ Heating and applies the composite construction that material is crystalline state, it is of course also possible to select not take
It is amorphous composite construction that In Situ Heating, which forms stress and applies material,.And in amorphous composite construction, due to stress
For applied layer B compared to phase transition function layer A, crystallization temperature is preferably lower, so can apply temperature field or apply electric field
It is preferentially converted into crystalline state in the process, to generate the effect of stress regulation and control during subsequent phase transition function layer A phase transformation.
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should all include
Within protection scope of the present invention.
Claims (10)
1. a kind of method based on crystal lattice stress regulation phase-change material Vacancy defect density, which is characterized in that this method is logical
It crosses and is inserted into stress application material into phase transition function material, thus regulate and control the vacancy defect concentration in the phase transition function material,
And thus obtain the composite construction that phase transition function material and stress application material chimeric growth generate；Its phase transformation of the composite construction is special
Property mainly determined by the phase transition function material therein, by the stress apply material regulation make its phase of the composite construction
Become characteristic and generate variation based on phase transition function material crystals its phase-change characteristic obtained by the pure phase transition function material,
And it is specially the material for being capable of forming crystalline state that the stress, which applies material,.
2. the method as described in claim 1 based on crystal lattice stress regulation phase-change material Vacancy defect density, which is characterized in that
When it is simultaneously crystalline state that the phase transition function material and the stress, which apply material, in the phase transition function material and the stress
Apply the lattice extension contact that the interface that material has a common boundary has these two types of materials；
Also, material is applied for the phase transition function material and the stress, is obtained by the pure phase transition function material
Phase transition function material crystals and the stress that material obtains is applied by the pure stress applies between material crystals these two types crystal
Lattice mismatch rate absolute value between 0.1% to 10%；
Preferably, its lattice constant of phase transition function material crystals obtained by the pure phase transition function material is less than by pure institute
It states stress and applies stress application its lattice constant of material crystals that material obtains.
3. the method as described in claim 1 based on crystal lattice stress regulation phase-change material Vacancy defect density, which is characterized in that
The stress that is inserted into phase transition function material applies the phase transition function layer that material is specifically constituted to the phase transition function material
The middle insertion stress applies the stress applied layer that material is constituted, and thus obtains phase transition function layer and stress applied layer alternating growth
The multi-layer film structure of generation.
4. the method as claimed in claim 3 based on crystal lattice stress regulation phase-change material Vacancy defect density, which is characterized in that
The multi-layer film structure is periodic multi-layer film structure；Any one period of the multi-layer film structure includes simultaneously a phase transformation
Functional layer and a stress applied layer, wherein the ratio between the thickness of the phase transition function layer and the stress applied layer meets 1:10
~10:1；The thickness in any one period meets 2-10nm, and total periodicity of the entire multi-layer film structure meets 5-100.
5. the method as claimed in claim 4 based on crystal lattice stress regulation phase-change material Vacancy defect density, which is characterized in that
For the multi-layer film structure, it is adjusted to the phase transition function ply stress particular by the thickness for adjusting stress applied layer
Size, and then the formation energy of vacancy defect is adjusted, to form different vacancy defect concentration.
6. the method as described in claim 1 based on crystal lattice stress regulation phase-change material Vacancy defect density, which is characterized in that
The phase transition function material does not contain the microcosmic non-laminar phase-change material in Van der Waals gap between atomic layer, and the stress applies
Material contains the microcosmic stratified material in Van der Waals gap between atomic layer；
Preferably, the phase transition function material is intrinsic or element doping pure metals or compound-material, wherein the list
Material is Sb simple substance, and the compound-material is the compound that Ge and Te is formed, the compound that Ge and Sb are formed, Ge, Sb, Te
The compound that three is formed, the compound that the compound or Ge, Sb, Bi, Te that Ge, Bi, Te three are formed are formed；Doping
Element be at least one of C, Cu, N, O, Si, Sc, Ti；It is the compound that Sb and Te is formed, Bi that the stress, which applies material,
The compound that the compound or Mo and S that the compound that the compound formed with Te, Ge and Se are formed, In and Se are formed are formed；
It is furthermore preferred that the phase transition function material is GeTe, GeSb, Ge2Sb2Te5Or Ge1Sb2Te4；The stress applies material
For Sb2Te3Or Bi2Te3。
7. using as claimed in any one of claims 1 to 6 based on crystal lattice stress regulation phase-change material Vacancy defect density
The corresponding obtained composite construction of method, which is characterized in that phase transition function material is chimeric with stress application material in the composite construction
Distribution.
8. composite construction as claimed in claim 7, which is characterized in that it is crystalline state that the stress, which applies material,.
9. using the phase transition storage of the composite construction as described in claim 7 or 8.
10. the method for preparing the composite construction as described in claim 7 or 8, which is characterized in that the preparation method is specifically to be based on magnetic
Control sputtering method, molecular-layer deposition method, molecular beam epitaxy, pulsed laser deposition, physical vapour deposition (PVD), chemical vapor deposition side
Method, thermal evaporation or electrochemical growing method.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110571331A (en) * | 2019-08-30 | 2019-12-13 | 华中科技大学 | stress-resistant superlattice phase change memory cell, preparation method thereof and phase change memory |
| CN110571235A (en) * | 2019-08-30 | 2019-12-13 | 华中科技大学 | three-dimensional superlattice phase change storage array and preparation method and application thereof |
| CN112578480A (en) * | 2019-09-29 | 2021-03-30 | 中国科学院长春光学精密机械与物理研究所 | Preparation method of multilayer film and multilayer film |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101540370A (en) * | 2009-04-23 | 2009-09-23 | 同济大学 | GeTe/Sb2Te3 multilayer nanocomposite phase transition film and preparation method |
| CN103606625A (en) * | 2013-11-28 | 2014-02-26 | 北京大学 | High-uniformity low-power-dissipation resistive random access memory and preparation method thereof |
| CN106941129A (en) * | 2017-01-17 | 2017-07-11 | 杭州电子科技大学 | A kind of GeTe/Bi for low power consumption phase changing memory2Te3Superlattice structure storage medium |
| US20180198064A1 (en) * | 2017-01-08 | 2018-07-12 | Intermolecular, Inc. | Current Compliance Layers and Memory Arrays Comprising Thereof |
| CN109686840A (en) * | 2018-12-26 | 2019-04-26 | 江苏理工学院 | Flexible multi-layered compound GeTe/ZnSb phase change film material of one kind and preparation method thereof |
-
2019
- 2019-01-31 CN CN201910095442.1A patent/CN109935685B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101540370A (en) * | 2009-04-23 | 2009-09-23 | 同济大学 | GeTe/Sb2Te3 multilayer nanocomposite phase transition film and preparation method |
| CN103606625A (en) * | 2013-11-28 | 2014-02-26 | 北京大学 | High-uniformity low-power-dissipation resistive random access memory and preparation method thereof |
| US20180198064A1 (en) * | 2017-01-08 | 2018-07-12 | Intermolecular, Inc. | Current Compliance Layers and Memory Arrays Comprising Thereof |
| CN106941129A (en) * | 2017-01-17 | 2017-07-11 | 杭州电子科技大学 | A kind of GeTe/Bi for low power consumption phase changing memory2Te3Superlattice structure storage medium |
| CN109686840A (en) * | 2018-12-26 | 2019-04-26 | 江苏理工学院 | Flexible multi-layered compound GeTe/ZnSb phase change film material of one kind and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| BING LU等: ""Logic gates realized by nonvolatile GeTe/Sb2Te3 super lattice phase-change memory with a magnetic field input"", 《APPLIED PHYSICS LETTERS》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110571331A (en) * | 2019-08-30 | 2019-12-13 | 华中科技大学 | stress-resistant superlattice phase change memory cell, preparation method thereof and phase change memory |
| CN110571235A (en) * | 2019-08-30 | 2019-12-13 | 华中科技大学 | three-dimensional superlattice phase change storage array and preparation method and application thereof |
| CN110571331B (en) * | 2019-08-30 | 2021-01-01 | 华中科技大学 | Stress-resistant superlattice phase change memory cell, preparation method thereof and phase change memory |
| CN112578480A (en) * | 2019-09-29 | 2021-03-30 | 中国科学院长春光学精密机械与物理研究所 | Preparation method of multilayer film and multilayer film |
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