CN100527420C - Bismuth ferric/bismuth titanate laminated construction electric capacity and method for preparing the same - Google Patents

Bismuth ferric/bismuth titanate laminated construction electric capacity and method for preparing the same Download PDF

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CN100527420C
CN100527420C CNB2007101757930A CN200710175793A CN100527420C CN 100527420 C CN100527420 C CN 100527420C CN B2007101757930 A CNB2007101757930 A CN B2007101757930A CN 200710175793 A CN200710175793 A CN 200710175793A CN 100527420 C CN100527420 C CN 100527420C
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bismuth
film
solution
bfo
bxt
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CN101136404A (en
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谢丹
任天令
臧永圆
刘理天
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Tsinghua University
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Abstract

This invention relates to a BFO/BXT laminated capacitor and its preparing method, in which, the capacitor includes: a substrate made of silicon and orderly combined with an oxidation layer, a lower electrode metal layer, a BFO film and an upper metal layer, in which, a BXT induction film is set between the lower electrode metal layer and the BFO film. The method includes: preparation of sol of RFO and BXT precursors and preparation of the capacitor of its laminated structure and the ferroelectric capacitor prepared with this method includes excellent property of anti-fatigue, high residual polarized intensity, low operational voltage and better dielectric property.

Description

Ferrous acid bismuth/bismuth titanate laminated construction electric capacity and preparation method thereof
Technical field
The invention belongs to microelectronics new material and device technology field, particularly be applicable to the ferrous acid bismuth (BiFeO of novel high-density memory and integrated ferroelectric device 3, be abbreviated as BFO)/bismuth titanates (Bi 4-xX xTi 3O 12, be abbreviated as BXT) and the preparation method of laminated construction electric capacity.
Background technology
Along with the development of microelectronic industry, memory is had higher requirement, for example: high-speed, low-power consumption, high security and non-volatile etc.Traditional SRAM, DRAM, E 2Memory such as PROM, FLASH all is to be storage medium with silicon, owing to the physics and the technologic limit, can not satisfy the further high speed development of information industry.Therefore, must seek and develop new storage medium.Ferroelectric material is that a class has the spontaneous polarization characteristic, and spontaneous polarization can be reversed and still retainable dielectric material when cutting off the power supply with electric field.Ferroelectric memory (FeRAM) is exactly to utilize this specific character, can realize the non-volatile storage of data.At present, the ferroelectric material that is used for FeRAM in the world mainly is lead zirconate titanate (PZT), but the remanent polarization of PZT is not high especially, therefore, is unfavorable for the application of high-density storage.Along with improving constantly of integrated circuit (IC) technology integrated level, the reducing of memory cell area, more and more higher to the requirement of polarization, therefore, the technology of PZT is confined to 130 nanometer nodes and has just reflected.
Tokyo polytechnical university has developed a kind of ferrous acid bismuth (BiFeO 3, be abbreviated as BFO) and the electric capacity of material, it has high remanent polarization at low temperatures evidence, but at room temperature, this BFO material has bigger electric leakage, thus greatly influence capacitive property.Therefore, the researcher mixes to it again subsequently, and develops a kind of BFO material that mixes manganese, and has at room temperature obtained high remanent polarization, but the electric capacity of existing BFO material characteristic at room temperature is relatively poor.
Summary of the invention
The objective of the invention is for overcoming the weak point of prior art, a kind of novel ferrous acid bismuth/bismuth titanate laminated construction electric capacity and preparation method thereof is proposed, the ferroelectric capacitor that utilizes this method to prepare has excellent fatigue resistance, higher remanent polarization (Pr), lower operating voltage (Vc), dielectric property preferably, and characteristics that can be compatible mutually with the CMOS technology, and at room temperature can operate as normal, be applicable to novel high-density memory and integrated ferroelectric device.
Ferrous acid bismuth of the present invention/bismuth titanate laminated construction electric capacity, this electric capacity comprises: is substrate with silicon, on this substrate, is combined with oxide layer, bottom electrode metal level, bismuth ferrite thin film successively, and the top electrode metal level; It is characterized in that, between described bottom electrode metal level and bismuth ferrite thin film, also be combined with bismuth titanates inducing layer film.
Described ferrous acid bismuth consist of BiFeO 3Described bismuth titanates consist of Bi 4-xX xTi 3O 12, X wherein is a rare earth element nd, La, and Sm, Pr, any one among the Gd etc., the X in the described bismuth titanates accounts for the mole percent of (X+Bi) total amount, in the scope of 0.1＜x＜1.0; Bi in the described bismuth titanates is with respect to described composition formula: Bi 4-xX xTi 3O 12Want excessive interpolation, the superfluous content of this Bi element, the mole percent that accounts for Bi, X and Ti element total amount is 5%＜Bi＜20% scope.
Described bismuth titanate film thickness can be 10nm～200nm, and described bismuth ferrite thin film thickness can be 20nm～500nm.The preparation method of above-mentioned ferrous acid bismuth/bismuth titanates laminated body, capacitor structure that the present invention proposes is the preparation by ferrous acid bismuth BFO and bismuth titanates BXT precursor sol, and preparation three parts of ferrous acid bismuth BFO/ bismuth titanates BXT laminated construction electric capacity composition, may further comprise the steps:
3) the described BXT precursor sol of preparation:
11) (0.3～5g) is dissolved in acetate (commercially available prod) or monoethanolamine (commercially available prod) or the EGME (commercially available prod), makes it be dissolved into the salting liquid of rare earth element fully with the acetate (commercially available prod) of rare earth element or nitrate (commercially available prod);
12) (3～40g) are dissolved in caproic acid (commercially available prod) or acetate (commercially available prod) makes it be dissolved into caproic acid bismuth solution or bismuth acetate solution fully with caproic acid bismuth (commercially available prod) or bismuth acetate (commercially available prod) or bismuth nitrate (commercially available prod);
13) the acetate solution with rare earth element adds in caproic acid bismuth solution or the bismuth acetate solution, fully stirs 5～30 minutes under 25～100 ℃ of conditions, to form the mixed solution of uniform rare earth element of clarification and bismuth;
14) measure isopropyl titanate (commercially available prod) (1～10g), add slowly in the above-mentioned mixed solution, under 25～100 ℃ of conditions, fully stirred 10～30 minutes, to form the uniform BXT solution of clarification;
15) with propyl alcohol or ethanol (commercially available prod, both can be used as solvent and also can be used as diluent) add in the above-mentioned BXT solution and dilute, the concentration range that makes BXT solution is 0.01～0.5mol/l, under 25～100 ℃ of conditions, stirred 10～60 minutes, until the BXT solution that forms evenly, concentration is moderate;
16) using the aperture is that the filter of 0.2～0.3 μ m is filtered described BXT solution into drop bottle, obtains the BXT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain the BXT precursor sol in about 5～10 days;
4) the described BFO precursor colloidal sol of preparation:
21) (0.1～10g) is dissolved in EGME (commercially available prod) or the acetate (commercially available prod), makes it be dissolved into the organic solution of iron fully with ethanol iron or ferric nitrate (commercially available prod);
22) (0.5～20g) is dissolved in caproic acid (commercially available prod) or acetate (commercially available prod) makes it be dissolved into caproic acid bismuth solution or bismuth acetate solution fully with caproic acid bismuth (commercially available prod) or bismuth acetate (commercially available prod) or bismuth nitrate (commercially available prod);
23) organic solution with iron adds in caproic acid bismuth solution or the bismuth acetate solution, fully stirs 10～40 minutes under 25～100 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will dilute in the above-mentioned iron bismuth mixed solution of acetate (commercially available prod) adding, with EGME or caproic acid (commercially available prod, both can be used as solvent and also can be used as thickener) add in the above-mentioned iron bismuth mixed solution and regulate viscosity, reach required viscosity of filming technology and concentration, and under 25～100 ℃ of conditions, stirred 20～60 minutes, until forming uniform, the moderate BFO solution of viscosity, the concentration range of BFO solution is 0.01～0.5mol/l;
25) using the aperture is that the filter of 0.2～0.3 μ m is filtered described BFO solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain the BFO precursor sol in about 1～3 day;
3) the described ferrous acid bismuth BFO/ bismuth titanates BXT laminated construction electric capacity of preparation:
31) adopt silicon Si to make substrate, it is cleaned oxidation then, the oxide layer of formation (routine techniques);
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, or platinum/titanium oxide Pt/TiO 2, or yittrium oxide/yttrium IrO 2/ Ir, platinum/yittrium oxide/yttrium Pt/IrO 2/ Ir, or ruthenium-oxide/ruthenium RuO 2A kind of among the/Ru (routine techniques);
33) preparation BXT inducing layer film on described bottom electrode comprises following five steps:
(a) utilize the method for spin coating to apply one deck BXT precursor colloidal sol after, the high speed centrifugation rotation forms skim BXT film, rotating speed is: 3000～4000 rev/mins; Time is: 20～100 seconds;
(b) described BXT film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 200～300 ℃, the time is: 5～10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300～400 ℃, the time is: 5～15 minutes;
(d) repeating step a)-step c), till BXT inducing layer film reaches preset thickness;
(e) then with this BXT film at 600～650 ℃, carry out subsequent annealing in oxygen or the nitrogen atmosphere, crystallization time is 10～30 minutes, obtains BXT inducing layer film;
34) growth BFO film on BXT inducing layer film comprises following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, rotating speed is: 3000～4500 rev/mins; Time is: 20～100 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 150～300 ℃, the time is: 5～10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300～400 ℃, the time is: 5～15 minutes;
(d) repeating step a)-step c), till the BFO film reaches preset thickness;
(e) then with this film at 500～650 ℃, carry out subsequent annealing in nitrogen or the oxygen atmosphere, crystallization time is 10～30 minutes, obtains the BFO film;
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, or yttrium/yittrium oxide Ir/IrO 2, yittrium oxide IrO 2, or ruthenium/ruthenium-oxide Ru/RuO 2Among a kind of (routine techniques), can obtain BFO/BXT laminated construction electric capacity product
Characteristics of the present invention and beneficial effect:
The present invention does not mix to BFO on the basis of existing BFO electric capacity, but adopts BXT as inducing layer, constitutes BFO/BXT laminated construction electric capacity.Its preparation method is with former researcher's difference: adopt different glue scheme (comprising employed solvent, complexing agent, diluent) and the thin film preparation processes (comprising: annealing temperature, annealing time, annealing atmosphere) of joining.
The BFO/BXT laminated construction electric capacity of the present invention's preparation at room temperature has bigger polarization intensity, lower operating voltage, and excellent fatigue resistance, the scope of dielectric property, and film thickness preferably is adjustable.Because this structure capacitive has lower preparation temperature, easily compatible mutually with the CMOS integrated technique, can make it be used for novel high-density memory and integrated ferroelectric device.Utilize the ferroelectric memory of this ferroelectric capacitor preparation to have outstanding advantages such as non-volatile, low-power consumption, high density, zero access, high anti-rewriting, highly anti-radiation ability.
Description of drawings
Fig. 1 is the BFO/BXT laminated construction electric capacity schematic diagram that is used for ferroelectric memory of the present invention.
Embodiment
Ferrous acid bismuth/bismuth titanate laminated construction electric capacity that the present invention proposes and preparation method thereof reaches embodiment in conjunction with the accompanying drawings and is described in detail as follows:
Ferrous acid bismuth (the BiFeO that the present invention proposes 3, be abbreviated as BFO)/bismuth titanates (Bi 4-xX xTi 3O 12, be abbreviated as BXT) laminated construction electric capacity as shown in Figure 1, this electric capacity comprises: be substrate 1 with silicon, be combined with oxide layer 2, bottom electrode metal level 3, bismuth titanates inducing layer film 4, bismuth ferrite thin film 5 successively on this substrate, and top electrode metal level 6.
Described electric capacity is to go up growth layer of oxide layer silicon dioxide SiO earlier in n type or p type silicon Si substrate 1 (thickness is 350 μ m～400 μ m) 22 (oxidated layer thickness is 300nm～500nm); Again at silicon dioxide SiO 2Sputter one deck bottom electrode 3 on 2 prepares BXT (Bi then on bottom electrode 3 4-xX xTi 3O 12) (film thickness is 10nm～200nm) to inducing layer film 4; X in the described bismuth titanates is a rare-earth elements La,, Nd, Sm, Pr, any one among the Gd, X account for the mole percent of (X+Bi) total amount, in the scope of 0.1＜x＜1.0; Bi in the described bismuth titanates is with respect to described composition formula: Bi 4-xX xTi 3O 12Want excessive interpolation, the superfluous content of this Bi element, the mole percent that accounts for Bi, X and Ti element total amount is 5%＜Bi＜20% scope; Again on BXT inducing layer film 4 preparation BFO film 5 (film thickness is 20nm～500nm), at last sputter top electrode 6 on BFO film 5.
Wherein, bottom electrode can be that (50nm～200nm)/Ti (20～100nm), or platinum/titanium oxide Pt (50nm～200nm)/TiO for platinum/titanium Pt 2(20～100nm), or yittrium oxide/yttrium IrO 2(10～100nm)/Ir (10～150nm), platinum/yittrium oxide/yttrium Pt (20～150nm)/IrO 2(10～100nm)/Ir (10～150nm), or ruthenium-oxide/ruthenium RuO 2((a kind of among 10～150nm), top electrode can be platinum Pt (20～150nm), or yttrium/yittrium oxide Ir (10～150nm)/IrO to 10～100nm)/Ru 2(10～100nm), yittrium oxide IrO 2(10～100nm), or ruthenium/ruthenium-oxide Ru (10～150nm)/RuO 2(a kind of among 10～100nm).
Embodiment 1
BXT in the electric capacity of present embodiment is Nd-doped Bi 4 Ti 3 O 12 Bi 4-xNd xTi 3O 12, its chemical composition and component are: Bi 3.15Nd 0.85Ti 3O 12(being BNT), the x among the described Nd is 0.85; Bi in the described Nd-doped Bi 4 Ti 3 O 12 is with respect to described component formula Bi 3.15Nd 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BNT film thickness is 10nm, and described BFO film thickness is 100nm.Concrete steps are as follows:
1) the described BNT precursor sol of preparation:
11) 1.366g acetic acid neodymium (commercially available prod) is dissolved in 10ml monoethanolamine (commercially available prod) and is mixed with consoluet acetic acid neodymium solution;
12) 15.422g caproic acid bismuth (commercially available prod) is dissolved in 25ml caproic acid (commercially available prod) and is made into consoluet caproic acid bismuth solution;
13) acetic acid neodymium solution is added in the caproic acid bismuth solution, under 25 ℃ of conditions, fully stirred 30 minutes, form the uniform neodymium bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned neodymium bismuth mixed solution, under 25 ℃ of conditions, fully stirred 30 minutes, form the uniform BNT dope of clarification;
15) add propyl alcohol in the BNT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 60 minutes under 25 ℃ of conditions, until the clarification of BNT solution evenly;
16) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BNT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BNT precursor sol that can obtain being used to get rid of film in about 5 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) organic solution with iron adds in the bismuth acetate solution, fully stirs 40 minutes under 25 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 25 ℃ of conditions, stirred 60 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 1 day
3) the described BFO/BNT laminated construction electric capacity of preparation:
31) adopt silicon n type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 300nm;
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, wherein, the thickness of Pt is about 180nm; The thickness of Ti is about 30nm;
33) preparation BNT inducing layer film on described bottom electrode comprises following five steps:
(a) utilize the method for spin coating to apply one deck BNT precursor colloidal sol after, the high speed centrifugation rotation forms skim BNT film, rotating speed is: 3000 rev/mins; Time is: 30 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 15 minutes;
(d) repeating step a)-step c), till obtaining the BNT film that thickness is 10nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 20 minutes, obtains BNT inducing layer film;
34) growth BFO film on BNT inducing layer film comprises following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, rotating speed is: 3000 rev/mins; Time is: 30 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 150 ℃, the time is: 10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300 ℃, the time is: 15 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 100nm;
(e) then with this film at 600 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 20 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, thickness are 150nm, can obtain BFO/BNT laminated construction electric capacity product
Embodiment 2
BXT in the electric capacity of present embodiment is Nd-doped Bi 4 Ti 3 O 12 Bi 4-xNd xTi 3O 12, its chemical composition and component are: Bi 3.15Nd 0.85Ti 3O 12(being BNT), the x among the described Nd is 0.85; Bi in the described Nd-doped Bi 4 Ti 3 O 12 is with respect to described component formula Bi 3.15Nd 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BNT film thickness is 20nm, and described BFO film thickness is 200nm.Concrete steps are as follows:
1) the described BNT precursor sol of preparation:
11) 1.366g acetic acid neodymium (commercially available prod) is dissolved in 10ml monoethanolamine (commercially available prod) and is mixed with consoluet acetic acid neodymium solution;
12) 11.712g bismuth nitrate (commercially available prod) is dissolved in 50ml acetate (commercially available prod), and adds the 10ml monoethanolamine, under 100 ℃ of conditions, fully stirred 20 minutes, bismuth nitrate is dissolved fully form bismuth acetate solution;
13) acetic acid neodymium solution is added in the bismuth acetate solution, under 100 ℃ of conditions, fully stirred 15 minutes, form the uniform neodymium bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned neodymium bismuth mixed solution, under 100 ℃ of conditions, fully stirred 10 minutes, form the uniform BNT dope of clarification;
15) add propyl alcohol in the BNT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 20 minutes under 100 ℃ of conditions, until the clarification of BNT solution evenly;
16) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BNT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BNT precursor sol that can obtain being used to get rid of film in about 6 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 2.903 caproic acid bismuths (commercially available prod) are dissolved in the 20ml caproic acid (commercially available prod), it is dissolved fully;
23) organic solution with iron adds in the bismuth acetate solution, fully stirs 20 minutes under 40 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 40 ℃ of conditions, stirred 30 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 3 days
3) the described BFO/BNT laminated construction electric capacity of preparation:
31) adopt silicon n type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 350nm;
32) sputter bottom electrode, electrode material is: platinum/titanium oxide Pt/TiO 2, wherein, the thickness 180nm of Pt, the thickness of Ti are 20nm;
33) preparation BNT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BNT precursor colloidal sol after, the high speed centrifugation rotation forms skim BNT film, even glue rotating speed is: 3000 rev/mins; Time is: 20 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 200 ℃, the time is: 10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300 ℃, the time is: 15 minutes;
(d) repeating step a)-step c), till obtaining the BNT film that thickness is 20nm;
(e) then with this film at 600 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 30 minutes, obtains BNT inducing layer film;
34) growth BFO film on BNT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 3500 rev/mins; Time is: 20 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 150 ℃, the time is: 10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300 ℃, the time is: 15 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 200nm;
(e) then with this film at 500 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 30 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, thickness are 100nm, can obtain BFO/BNT laminated construction electric capacity product
Embodiment 3
BXT in the electric capacity of present embodiment is Nd-doped Bi 4 Ti 3 O 12 Bi 4-xNd xTi 3O 12, its chemical composition and component are: Bi 3.15Nd 0.85Ti 3O 12(being BNT), the x among the described Nd is 0.85; Bi in the described Nd-doped Bi 4 Ti 3 O 12 is with respect to described component formula Bi 3.15Nd 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BNT film thickness is 50nm, and described BFO film thickness is 300nm.Concrete steps are as follows:
1) the described BNT precursor sol of preparation:
11) 1.366g acetic acid neodymium (commercially available prod) is dissolved in 10ml monoethanolamine (commercially available prod) and is mixed with consoluet acetic acid neodymium solution;
12) 9.394 bismuth acetates (commercially available prod) are dissolved in 40ml glacial acetic acid (commercially available prod), under 80 ℃ of conditions, fully stirred 10 minutes, bismuth acetate is dissolved fully form bismuth acetate solution;
13) acetic acid neodymium solution is added in the bismuth acetate solution, under 80 ℃ of conditions, fully stirred 15 minutes, form the uniform neodymium bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned neodymium bismuth mixed solution, under 80 ℃ of conditions, fully stirred 10 minutes, form the uniform BNT dope of clarification;
15) add propyl alcohol in the BNT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 10 minutes under 80 ℃ of conditions, until the clarification of BNT solution evenly;
16) using the aperture is that the filter of 0.25 μ m is filtered solution into drop bottle, obtains the BNT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BNT precursor sol that can obtain being used to get rid of film in about 8 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) organic solution with iron adds in the bismuth acetate solution, fully stirs 10 minutes under 100 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 15ml caproic acid and regulate viscosity, under 100 ℃ of conditions, stirred 10 minutes, until form uniformly, the moderate BFO solution of viscosity;
Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.25 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 2 days
3) the described BFO/BNT laminated construction electric capacity of preparation:
31) adopt silicon n type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 400nm;
32) sputter bottom electrode, electrode material is: yittrium oxide/yttrium IrO 2/ Ir, wherein, IrO 2Thickness be 10～20nm, the thickness of Ir is 50～60nm;
33) preparation BNT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BNT precursor colloidal sol after, the high speed centrifugation rotation forms skim BNT film, even glue rotating speed is: 4000 rev/mins; Time is: 100 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 300 ℃, the time is: 5 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 400 ℃, the time is: 5 minutes;
(d) repeating step a)-step c), till obtaining the BNT film that thickness is 50nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 10 minutes, obtains BNT inducing layer film;
34) growth BFO film on BNT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 4500 rev/mins; Time is: 100 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 300 ℃, the time is: 5 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 400 ℃, the time is: 5 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 300nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 10 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: yttrium/yittrium oxide Ir/IrO 2, the thickness of Ir is 20～30nm, IrO 2Thickness is 10～20nm, can obtain BFO/BNT laminated construction electric capacity product
Embodiment 4
BXT in the electric capacity of present embodiment is Nd-doped Bi 4 Ti 3 O 12 Bi 4-xNd xTi 3O 12, its chemical composition and component are: Bi 3.15Nd 0.85Ti 3O 12(being BNT), the x among the described Nd is 0.85; Bi in the described Nd-doped Bi 4 Ti 3 O 12 is with respect to described component formula Bi 3.15Nd 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BNT film thickness is 80nm, and described BFO film thickness is 400nm.Concrete steps are as follows:
1) the described BNT precursor sol of preparation:
11) 1.366g acetic acid neodymium (commercially available prod) is dissolved in 10ml monoethanolamine (commercially available prod) and is mixed with consoluet acetic acid neodymium solution;
12) 15.422g caproic acid bismuth (commercially available prod) is dissolved in 25ml caproic acid (commercially available prod) and is made into consoluet caproic acid bismuth solution;
13) acetic acid neodymium solution is added in the caproic acid bismuth solution, under 80 ℃ of conditions, fully stirred 5 minutes, form the uniform neodymium bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned neodymium bismuth mixed solution, under 80 ℃ of conditions, fully stirred 10 minutes, form the uniform BNT dope of clarification;
15) add propyl alcohol in the BNT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 20 minutes under 80 ℃ of conditions, until the clarification of BNT solution evenly;
16) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BNT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BNT precursor sol that can obtain being used to get rid of film in about 5 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.871g ferric nitrate (commercially available prod) is dissolved in the 30ml acetate (commercially available prod), and adds the 15ml monoethanolamine, under 50 ℃ of conditions, fully stirred 20 minutes, make it dissolve the acetic acid solution that forms iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) acetic acid solution with iron adds in the bismuth acetate solution, fully stirs 20 minutes under 50 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 40 ℃ of conditions, stirred 30 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 1 day
3) the described BFO/BNT laminated construction electric capacity of preparation:
31) adopt silicon p type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 500nm;
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, wherein, the thickness 200nm of Pt, the thickness of Ti are 30nm;
33) preparation BNT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BNT precursor colloidal sol after, the high speed centrifugation rotation forms skim BNT film, even glue rotating speed is: 3500 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till obtaining the BNT film that thickness is 80nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the oxygen atmosphere, crystallization time is 20 minutes, obtains BNT inducing layer film;
34) growth BFO film on BNT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 4000 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 400nm;
(e) then with this film at 550 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 20 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, thickness are 20nm, can obtain BFO/BNT laminated construction electric capacity product
Embodiment 5
Nd-doped Bi 4 Ti 3 O 12 Bi in the electric capacity of present embodiment 4-xNd xTi 3O 12The composition of ferroelectric thin film and component are: Bi 3.75Nd 0.25Ti 3O 12, the x among the described Nd is 0.25; Bi in the described Nd-doped Bi 4 Ti 3 O 12 is with respect to described component formula Bi 3.75Nd 0.25Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 5% of each element total amount; Described film thickness is 100nm, and described BFO film thickness is 500nm.Concrete steps are as follows:
1) the described BNT precursor sol of preparation:
11) 0.402g acetic acid neodymium (commercially available prod) is dissolved in 10ml monoethanolamine (commercially available prod) and is mixed with consoluet acetic acid neodymium solution;
12) 13.942g bismuth nitrate (commercially available prod) is dissolved in 50ml acetate (commercially available prod), and adds the 10ml monoethanolamine, under 100 ℃ of conditions, fully stirred 20 minutes, it is dissolved fully form bismuth acetate solution;
13) acetic acid neodymium solution is added in the bismuth acetate solution, under 100 ℃ of conditions, fully stirred 15 minutes, form the uniform neodymium bismuth mixed solution of clarification;
14) measure isopropyl titanate 4.351g, add above-mentioned neodymium bismuth mixed solution slowly, under 100 ℃ of conditions, fully stirred 20 minutes, form the uniform BNT dope of clarification;
15) adding ethanol in the BNT dope, to be diluted to 200ml concentration be 0.4mol/l, stirred 30 minutes under 100 ℃ of conditions, until the clarification of BNT solution evenly;
16) using the aperture is that the filter of 0.3 μ m is filtered solution into drop bottle, obtains the BNT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BNT colloidal sol that can obtain being used to get rid of film in about 10 days
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) organic solution with iron adds in the bismuth acetate solution, fully stirs 40 minutes under 25 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 25 ℃ of conditions, stirred 60 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.3 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 1 day
3) the described BFO/BNT laminated construction electric capacity of preparation:
31) adopt silicon p type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 350nm;
32) sputter bottom electrode, electrode material is: ruthenium-oxide/ruthenium RuO 2/ Ru, wherein, RuO 2Thickness be 10～20nm, thickness 50～60nm of Ru;
33) preparation BNT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BNT precursor colloidal sol after, the high speed centrifugation rotation forms skim BNT film, even glue rotating speed is: 3000 rev/mins; Time is: 30 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 380 ℃, the time is: 15 minutes;
(d) repeating step a)-step c), till obtaining the BNT film that thickness is 100nm;
(e) then with this film at 600 ℃, carry out subsequent annealing in the oxygen atmosphere, crystallization time is 20 minutes, obtains BNT inducing layer film;
34) growth BFO film on BNT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 3500 rev/mins; Time is: 30 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 200 ℃, the time is: 10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 380 ℃, the time is: 15 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 500nm;
(e) then with this film at 550 ℃, carry out subsequent annealing in the oxygen atmosphere, crystallization time is 30 minutes, obtains the BFO film;
35) sputter top electrode on the BFO film, electrode material is: ruthenium/ruthenium-oxide, wherein, thickness 20～30nm of Ru, RuO 2Thickness be 10～20nm, can obtain BFO/BNT laminated construction electric capacity product
Embodiment 6
BXT in the electric capacity of present embodiment is for mixing lanthanum bismuth titanates Bi 4-xLa xTi 3O 12, its chemical composition and component are: Bi 3.15La 0.85Ti 3O 12(being BLT), the x among the described La is 0.85; The described Bi that mixes in the lanthanum bismuth titanates is with respect to described component formula Bi 3.15La 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BLT film thickness is 20nm, and described BFO film thickness is 200nm.Concrete steps are as follows:
1) the described BLT precursor sol of preparation:
11) 1.824g lanthanum nitrate (commercially available prod) is dissolved in the organic solution that 20ml EGME (commercially available prod) is mixed with consoluet lanthanum;
12) 15.422g caproic acid bismuth (commercially available prod) is dissolved in 25ml caproic acid (commercially available prod) and is made into consoluet caproic acid bismuth solution;
13) organic solution with lanthanum adds in the caproic acid bismuth solution, fully stirs 5 minutes under 80 ℃ of conditions, forms the uniform lanthanum bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned lanthanum bismuth mixed solution, under 80 ℃ of conditions, fully stirred 10 minutes, form the uniform BLT dope of clarification;
15) add propyl alcohol in the BLT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 20 minutes under 80 ℃ of conditions, until the clarification of BLT solution evenly;
16) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BLT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BLT precursor sol that can obtain being used to get rid of film in about 5 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) acetic acid solution with iron adds in the bismuth acetate solution, fully stirs 20 minutes under 50 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 40 ℃ of conditions, stirred 30 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 1 day
3) the described BFO/BLT laminated construction electric capacity of preparation:
31) adopt silicon p type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 350nm;
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, wherein, the thickness 200nm of Pt, the thickness of Ti are 30nm;
33) preparation BLT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BLT precursor colloidal sol after, the high speed centrifugation rotation forms skim BLT film, even glue rotating speed is: 3500 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till obtaining the BLT film that thickness is 20nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the oxygen atmosphere, crystallization time is 20 minutes, obtains BLT inducing layer film;
34) growth BFO film on BLT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 4000 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 200nm;
(e) then with this film at 550 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 20 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, thickness are 20nm, can obtain BFO/BLT laminated construction electric capacity product
Embodiment 7
BXT in the electric capacity of present embodiment is for mixing samarium bismuth titanates Bi 4-xSm xTi 3O 12, its chemical composition and component are: Bi 3.15Sm 0.85Ti 3O 12(being BSmT), the x among the described Sm is 0.85; The described Bi that mixes in the samarium bismuth titanates is with respect to described component formula Bi 3.15Sm 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BSmT film thickness is 20nm, and described BFO film thickness is 200nm.Concrete steps are as follows:
1) the described BSmT precursor sol of preparation:
11) 1.681g acetic acid samarium (commercially available prod) is dissolved in 20ml acetate (commercially available prod) and is mixed with consoluet acetate samarium solution;
12) 15.422g caproic acid bismuth (commercially available prod) is dissolved in 25ml caproic acid (commercially available prod) and is made into consoluet caproic acid bismuth solution;
13) acetate samarium solution is added in the caproic acid bismuth solution, under 80 ℃ of conditions, fully stirred 5 minutes, form the uniform samarium bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned samarium bismuth mixed solution, under 80 ℃ of conditions, fully stirred 10 minutes, form the uniform BSmT dope of clarification;
15) add propyl alcohol in the BSmT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 20 minutes under 80 ℃ of conditions, until the clarification of BSmT solution evenly;
16) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BSmT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BSmT precursor sol that can obtain being used to get rid of film in about 5 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) acetic acid solution with iron adds in the bismuth acetate solution, fully stirs 20 minutes under 50 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 40 ℃ of conditions, stirred 30 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 1 day
3) the described BFO/BSmT laminated construction electric capacity of preparation:
31) adopt silicon p type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 350nm;
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, wherein, the thickness 200nm of Pt, the thickness of Ti are 30nm;
33) preparation BSmT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BSmT precursor colloidal sol after, the high speed centrifugation rotation forms skim BSmT film, even glue rotating speed is: 3500 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till obtaining the BSmT film that thickness is 20nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the oxygen atmosphere, crystallization time is 20 minutes, obtains BSmT inducing layer film;
34) growth BFO film on BSmT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 4000 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 200nm;
(e) then with this film at 550 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 20 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, thickness are 20nm, can obtain BFO/BSmT laminated construction electric capacity product
Embodiment 8
BXT in the electric capacity of present embodiment is for mixing praseodymium bismuth titanates Bi 4-xPr xTi 3O 12, its chemical composition and component are: Bi 3.15Pr 0.85Ti 3O 12(being BPT), the x among the described Pr is 0.85; The described Bi that mixes in the praseodymium bismuth titanates is with respect to described component formula Bi 3.15Pr 0.85Ti 3O 12Content want excessive interpolation, the excessive percentage of this Bi element is 20% of each element total amount; Described BPT film thickness is 20nm, and described BFO film thickness is 200nm.Concrete steps are as follows:
1) the described BPT precursor sol of preparation:
11) 1.833g praseodymium nitrate (commercially available prod) is dissolved in the organic solution that 20ml EGME (commercially available prod) is mixed with consoluet praseodymium;
12) 15.422g caproic acid bismuth (commercially available prod) is dissolved in 25ml caproic acid (commercially available prod) and is made into consoluet caproic acid bismuth solution;
13) organic solution with praseodymium adds in the caproic acid bismuth solution, fully stirs 5 minutes under 80 ℃ of conditions, forms the uniform praseodymium bismuth mixed solution of clarification
14) measure isopropyl titanate 4.351g, add slowly in the above-mentioned praseodymium bismuth mixed solution, under 80 ℃ of conditions, fully stirred 10 minutes, form the uniform BPT dope of clarification;
15) add propyl alcohol in the BLT dope and be diluted to 200ml, its concentration is 0.025mol/l, stirs 20 minutes under 80 ℃ of conditions, until the clarification of BPT solution evenly;
16) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BPT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill the BPT precursor sol that can obtain being used to get rid of film in about 5 days.
2) the described BFO precursor colloidal sol of preparation:
21) 0.687g ethanol iron (commercially available prod) is dissolved in the 10ml EGME (commercially available prod), makes it be dissolved into the organic solution of iron fully;
22) 1.755g bismuth acetate (commercially available prod) is dissolved in the 20ml acetate (commercially available prod), it is dissolved fully;
23) acetic acid solution with iron adds in the bismuth acetate solution, fully stirs 20 minutes under 50 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) will 20ml acetate (commercially available prod) add in the above-mentioned iron bismuth mixed solution and dilute, and add the 10ml EGME and regulate viscosity, under 40 ℃ of conditions, stirred 30 minutes, until form uniformly, the moderate BFO solution of viscosity; Its solution concentration is 0.25mol/l;
25) using the aperture is that the filter of 0.2 μ m is filtered solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain BFO colloidal sol in about 1 day
3) the described BFO/BPT laminated construction electric capacity of preparation:
31) adopt silicon p type (100) Si to make substrate, thickness is 340～400 μ m; It is cleaned, oxidation then, oxidated layer thickness is about 350nm;
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, wherein, the thickness 200nm of Pt, the thickness of Ti are 30nm;
33) preparation BPT inducing layer film on described bottom electrode has following five steps:
(a) utilize the method for spin coating to apply one deck BPT precursor colloidal sol after, the high speed centrifugation rotation forms skim BPT film, even glue rotating speed is: 3500 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till obtaining the BPT film that thickness is 20nm;
(e) then with this film at 650 ℃, carry out subsequent annealing in the oxygen atmosphere, crystallization time is 20 minutes, obtains BPT inducing layer film;
34) growth BFO film on BPT inducing layer film, divide following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, even glue rotating speed is: 4000 rev/mins; Time is: 60 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 250 ℃, the time is: 8 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 350 ℃, the time is: 10 minutes;
(d) repeating step a)-step c), till the BFO film thickness reaches 200nm;
(e) then with this film at 550 ℃, carry out subsequent annealing in the nitrogen atmosphere, crystallization time is 20 minutes, obtains the BFO film.
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, thickness are 20nm, can obtain BFO/BPT laminated construction electric capacity product.

Claims (4)

1, a kind of ferrous acid bismuth/bismuth titanate laminated construction electric capacity, this electric capacity comprises: is substrate with silicon, on this substrate, is combined with oxide layer, bottom electrode metal level, bismuth ferrite thin film successively, and the top electrode metal level; It is characterized in that, between described bottom electrode metal level and bismuth ferrite thin film, also be combined with bismuth titanates inducing layer film.
2, electric capacity as claimed in claim 1 is characterized in that, described bismuth titanates consist of Bi 4-xX xTi 3O 12, X wherein is a rare earth element nd, La, and Sm, Pr, any one among the Gd, the X in the described bismuth titanates account for the mole percent of X and Bi total amount in the scope of 10%＜X＜100%; Bi in the described bismuth titanates is with respect to described composition formula: Bi 4-xX xTi 3O 12Want excessive interpolation, the mole percent that the superfluous content of this Bi element accounts for Bi, X and Ti element total amount is 5%＜Bi＜20% scope.
3, electric capacity as claimed in claim 1 is characterized in that, described bismuth titanate film thickness is 10nm～200nm, and described bismuth ferrite thin film thickness is 20nm～500nm.
4, a kind of preparation method of electric capacity according to claim 1 is characterized in that, by the preparation of ferrous acid bismuth BFO and bismuth titanates BXT precursor sol, and preparation three parts of ferrous acid bismuth BFO/ bismuth titanates BXT laminated construction electric capacity composition, may further comprise the steps:
1) the described BXT precursor sol of preparation:
11) the acetate 0.3～5g with rare earth element is dissolved in acetate or monoethanolamine or the EGME, makes it be dissolved into the salting liquid of rare earth element fully;
12) with caproic acid bismuth or bismuth acetate or bismuth nitrate 3～40g is dissolved in caproic acid or acetate makes it be dissolved into caproic acid bismuth solution or bismuth acetate solution fully;
13) the acetate solution with rare earth element adds in caproic acid bismuth solution or the bismuth acetate solution, fully stirs 5～30 minutes under 25～100 ℃ of conditions, to form the mixed solution of uniform rare earth element of clarification and bismuth;
14) measure isopropyl titanate 1～10g, add slowly in the above-mentioned mixed solution, under 25～100 ℃ of conditions, fully stirred 10～30 minutes, to form the uniform BXT solution of clarification;
15) propyl alcohol or ethanol are added in the above-mentioned BXT solution dilute, the concentration range that makes BXT solution is 0.01～0.5mol/l, stirs 10～60 minutes under 25～100 ℃ of conditions, until the BXT solution that forms evenly, concentration is moderate;
16) using the aperture is that the filter of 0.2～0.3 μ m is filtered described BXT solution into drop bottle, obtains the BXT precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain the BXT precursor sol in 5～10 days;
2) the described BFO precursor colloidal sol of preparation:
21) ethanol iron or ferric nitrate 0.1～10g are dissolved in EGME or the acetate, make it be dissolved into the organic solution of iron fully;
22) with caproic acid bismuth or bismuth acetate or bismuth nitrate 0.5～20g is dissolved in caproic acid or acetate makes it be dissolved into caproic acid bismuth solution or bismuth acetate solution fully;
23) organic solution with iron adds in caproic acid bismuth solution or the bismuth acetate solution, fully stirs 10～40 minutes under 25～100 ℃ of conditions, to form the uniform iron bismuth mixed solution of clarification;
24) acetate is added in the above-mentioned iron bismuth mixed solution and dilute, EGME or caproic acid added in the above-mentioned iron bismuth mixed solution regulate viscosity, reach required viscosity of filming technology and concentration, and under 25～100 ℃ of conditions, stirred 20～60 minutes, until forming uniform, the moderate BFO solution of viscosity, the concentration range of BFO solution is 0.01～0.5mol/l;
25) using the aperture is that the filter of 0.2～0.3 μ m is filtered described BFO solution into drop bottle, obtains the BFO precursor solution of homogeneous transparent, puts into refrigerator cold-storage and leaves standstill and can obtain the BFO precursor sol in about 1～3 day;
3) the described ferrous acid bismuth BFO/ bismuth titanates BXT laminated construction electric capacity of preparation:
31) adopt silicon Si to make substrate, it is cleaned oxidation then, the oxide layer of formation;
32) sputter bottom electrode, electrode material is: platinum/titanium Pt/Ti, or platinum/titanium oxide Pt/TiO 2, or yittrium oxide/yttrium IrO 2/ Ir, platinum/yittrium oxide/yttrium Pt/IrO 2/ Ir, or ruthenium-oxide/ruthenium RuO 2A kind of among the/Ru;
33) preparation BXT inducing layer film on described bottom electrode comprises following five steps:
(a) utilize the method for spin coating to apply one deck BXT precursor colloidal sol after, the high speed centrifugation rotation forms skim BXT film, rotating speed is: 3000～4000 rev/mins; Time is: 20～100 seconds;
(b) described BXT film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 200～300 ℃, the time is: 5～10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300～400 ℃, the time is: 5～15 minutes;
(d) repeating step a)-step c), till BXT inducing layer film reaches preset thickness;
(e) then with this BXT film at 600～650 ℃, carry out subsequent annealing in oxygen or the nitrogen atmosphere, crystallization time is 10～30 minutes, obtains BXT inducing layer film;
34) growth BFO film on BXT inducing layer film comprises following five steps:
(a) utilize the method for spin coating to apply one deck BFO precursor colloidal sol after, the high speed centrifugation rotation forms skim BFO film, rotating speed is: 3000～4500 rev/mins; Time is: 20～100 seconds;
(b) described film is placed on carries out preceding baking on the hot plate, pre-bake temperature is: 150～300 ℃, the time is: 5～10 minutes;
(c) again the film after the preceding baking is carried out pyrolysis, pyrolysis temperature is: 300～400 ℃, the time is: 5～15 minutes;
(d) repeating step a)-step c), till the BFO film reaches preset thickness;
(e) then with this film at 500～650 ℃, carry out subsequent annealing in nitrogen or the oxygen atmosphere, crystallization time is 10～30 minutes, obtains the BFO film;
35) sputter top electrode on the BFO film, electrode material is: platinum Pt, or yttrium/yittrium oxide Ir/IrO 2, yittrium oxide IrO 2, or ruthenium/ruthenium-oxide Ru/RuO 2Among a kind of, obtain BFO/BXT laminated construction electric capacity product.
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