CN1791706A - Method for producing single crystal of multi- element oxide single crystal containing bismuth as constituting element - Google Patents

Method for producing single crystal of multi- element oxide single crystal containing bismuth as constituting element Download PDF

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CN1791706A
CN1791706A CN 200480013927 CN200480013927A CN1791706A CN 1791706 A CN1791706 A CN 1791706A CN 200480013927 CN200480013927 CN 200480013927 CN 200480013927 A CN200480013927 A CN 200480013927A CN 1791706 A CN1791706 A CN 1791706A
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substrate
fusing assistant
cuo
film
tio
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CN100334262C (en
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鲤沼秀臣
松本祐司
高桥龟太
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Japan Science and Technology Agency
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Abstract

A method for producing a multi-element oxide single crystal containing Bi as a constituting element, such as (Bi2O2)Am-1BmO3m+1 [wherein A represents Sr, Ba, Ca, Bi or the like, and B represents Ti, Ta or Nb], which comprises depositing a flux comprising a composition satisfying, in mole ratio, 0 < CUO/BI2O3 < 2 AND 0 <= TIO/BI2O3 < 7/6 on a substrate, and then depositing a single crystal on the substrate via said flux deposition layer, or comprises preparing a melt comprising a composition having the above mole ratios in the sum of a raw material and a flux and cooling the melt to thereby form a single crystal, or comprises depositing a flux comprising CuO on a substrate, and then depositing by the use of Bi6Ti3O12 to Bi8Ti3O12 as a target, which has excess Bi as compared with the objective film, to thereby supply Bi-Ti-O to said flux deposited layer and form a single crystal of Bi4Ti3O12 on the substrate.

Description

Contain the manufacture method of bismuth as the multielement oxide monocrystal that constitutes element
Technical field
The present invention relates to use that fusing assistant makes the film of crystallinity excellence or large volume contains the method for bismuth as the multielement oxide monocrystal that constitutes element.
Background technology
As making Bi 4Ti 3O 12Deng containing the method for bismuth as the multielement oxide monocrystal film that constitutes element, (for example, patent documentation 1～6) such as known spatter method, MBE method, pulse laser method of piling, mocvd methods.In addition, as one of manufacture method of monocrystalline, known with raw material beyond the target substance reaction, and segregative compound is elected to be flux (fusing assistant), in solution, cultivate the flux method (patent documentation 7) of monocrystalline.Using flux method manufacturing Bi 4Ti 3O 12The large volume monocrystalline time, can use Bi 2O 3As fusing assistant (non-patent literature 1,2).
Fusing assistant is the additive that uses when making monocrystalline.Fusing assistant can promote crystalline to grow up, and reduces the material of synthesis temperature with synthetic thermodynamic instability.The situation that this fusing assistant is applied in the thin-film technique is the epitaxy (non-patent literature 3,4) of fusing assistant.Recently, the known high quality thin film that can make the monocrystalline level of large volume by this fusing assistant epitaxy.
Present inventors have formerly proposed patent application (patent documentation 8) for the relevant invention of method of using 3 phase epitaxy flop-in methods to make the monocrystalline oxide film.This method is to pile up flux material in advance on substrate, piles up the method for high quality thin film then by the fusing assistant layer, and flux material is used Ba-Cu-O.This is to be known for a long time flux material to the large volume monocrystalline, and this flux material is NdBa 2Cu 3O 7The formation element of monocrystalline.
Patent documentation 1: the spy opens clear 61-61240 communique
Patent documentation 2: the spy opens (speciallyying permit No. 2547203) communique clear 63-171869 number
Patent documentation 3: the spy opens (speciallyying permit No. 2547204) communique clear 63-171870 number
Patent documentation 4: the spy opens (speciallyying permit No. 3195827) communique flat 05-246722 number
Patent documentation 5: the spy opens flat 09-67197 communique
Patent documentation 6: the spy opens (speciallyying permit No. 2939530) communique flat 10-158094 number
Patent documentation 7: the spy opens flat 10-338599 communique
Patent documentation 8: the spy opens the 2002-68893 communique
Non-patent literature 1:Yoichiro Matsuda, Hiroshi Matsumoto, Akira Baba, Takashi Goto, and Toshio Hirai, Jpn.J.Appl.Phys.Vol.31, (1992) 3108
Non-patent literature 2:Rintaro Aoyagi, Hiroaki Takeda, Soichiro Okamura, Tadashi Shiosaki, Jpn.J.Appl.Phys.Vol.40 (2001) 5671
Non-patent literature 3:K.S.Yun, B.D.Choi, Y.Matsumoto, J.H.Song, N.Kanda, T.Itoh, M.Kawasaki, T.chikyowl and P.Ahmet, H.Koinuma, Appl.Phys.Lett.80,61-63 (2002)
Non-patent literature 4: high bridge dragon too he " the 50th respond unite the speech meeting pre-original text collection of giving a lecture " with the physics relation, p658, (2003.3)
Summary of the invention
If use above-mentioned these method build-up film on substrate such as spatter method, MBE method, pulse laser method of piling, mocvd method, then may lack the film of the high Bi of vapour pressure.In addition, such as patent documentation 6 record, under the atmosphere of Bi surplus, make in the method for film, contain too much Bi, crystallinity is poor.In addition, general formula (Bi 2O 2) A M-1B mO 3m+1(A=Sr, Ba, Ca, Bi etc., B=Ti, Ta, Nb) the bismuth layer forceful electric power dielectric material shown in is Bi 4Ti 3O 12, Bi 4BaTi 4O 15, Bi 4SrTi 4O 15, Bi 4CaTi 4O 15, SrBi 2Ta 2O 9Or SrBi 2Nb 2O 9Deng the ferroele ctric oxide compound, these ferroele ctric oxide compounds use Bi 2O 3Fusing assistant is made monocrystalline, but Bi 2O 3Fusing assistant uses environmentally harmful Bi, so must reduce its consumption.
The objective of the invention is to solve the problems referred to above in the existing method, be provided at and make Bi 4Ti 3O 12, Bi 4BaTi 4O 15, Bi 4SrTi 4O 15, Bi 4CaTi 4O 15, SrBi 2Ta 2O 9Or SrBi 2Nb 2O 9Deng containing Bi when constituting the multielement oxide monocrystal of element, can irrespectively make the method for the oxide monocrystal of crystallinity excellence with manufacture method.
The present invention makes with the method for Bi as the film and the large volume monocrystalline of constituent, when forming film on substrate, piles up the fusing assistant layer in advance on substrate, and piling up on substrate with Bi by this fusing assistant layer is the monocrystal thin films of constituent.In addition, can make the oxide monocrystal of crystallinity excellence: when cultivating the large volume monocrystalline, cultivate with raw material and fusing assistant manufacturing liquation,, produce the target nucleus, cultivate crystallization with its slow cooling by oxide monocrystal by following flux method.
Just, the present invention (1) is the manufacture method of a kind of bismuth-containing as the multielement oxide monocrystal that constitutes element, and it is characterized in that: pile up fusing assistant on substrate in advance, wherein fusing assistant is with mol ratio 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 3The fusing assistant that 3 yuan of system combinations of-CuO-TiO constitute is piled up monocrystal thin films by this fusing assistant accumulation horizon on substrate.
In addition, the present invention (2) is the manufacture method of a kind of bismuth-containing as the multielement oxide monocrystal that constitutes element, it is characterized in that: after piling up the fusing assistant that is made of CuO on the substrate, use with the target film composition and compare the Bi of Bi surplus 6Ti 3O 12～Bi 8Ti 3O 12As target, by piling up Bi-Ti-O is supplied to this fusing assistant accumulation horizon, on substrate, form Bi simultaneously 4Ti 3O 12The single crystal film.
In addition, the present invention (3) is according to the manufacture method of the oxide monocrystal of above-mentioned (1) or (2), it is characterized in that: the accumulation of aforementioned fusing assistant and monocrystal thin films is undertaken by spatter method, MBE method, pulse laser method of piling or mocvd method.
In addition, the present invention (4) is that it is characterized in that: substrate is SrTiO according to each the manufacture method of oxide monocrystal of above-mentioned (1)～(3) 3(001) substrate, Al 2O 3Substrate, Si substrate, LaAlO 3Substrate, MgO substrate or NdGaO 3Substrate.
In addition, the present invention (5) is a kind of manufacture method that contains bismuth as the multielement oxide monocrystal that constitutes element, and it is characterized in that: making the composition that contains raw material and fusing assistant is 0＜CuO/Bi with molar ratio computing 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 3The liquation that 3 yuan of system combinations of-CuO-TiO constitute with its cooling, is cultivated monocrystalline.
In addition, the present invention (6) is according to the manufacture method of the oxide monocrystal of each record of above-mentioned (1)～(5), it is characterized in that: bismuth-containing is Bi as the multielement oxide monocrystal that constitutes element 4Ti 3O 12, Bi 4BaTi 4O 15, Bi 4SrTi 4O 15, Bi 4CaTi 4O 15, SrBi 2Ta 2O 9Or SrBi 2Nb 2O 9
If the use mol ratio is 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 3The fusing assistant layer that 3 yuan of system combinations of-CuO-TiO constitute is piled up the oxide monocrystal film by this fusing assistant layer on substrate, then with do not have fusing assistant and use Bi separately 2O 3Compare during fusing assistant, can make the better film of crystallinity.This can think owing to contain CuO the fusing point of fusing assistant is uprised, and CuO can be used as a kind of catalyzer use simultaneously, the crystalline growth of control film, and crystallinity improves and the surface is the smooth film of atom level thereby make.TiO has the purposes of the above-mentioned effect that promotes CuO.
In addition, after piling up the fusing assistant of CuO formation on the substrate, use and compare the Bi of Bi surplus with the composition of target film 6Ti 3O 12～Bi 8Ti 3O 12As target, by piling up, Bi-Ti-O is supplied to this fusing assistant accumulation horizon, on substrate, form Bi simultaneously 4Ti 3O 12The single crystal film, in this case, the excess components of Bi uses as fusing assistant, plays the function of Bi-Cu-O fusing assistant at last.This method is at the SrBi that does not have the Ti composition 2Ta 2O 9Or SrBi 2Nb 2O 9Deng the manufacturing of monocrystal thin films in be preferable methods.
In the film that does not have fusing assistant in the past, can observe defective, dislocation, perhaps the length of C axle is different with the value of large volume.But, fusing assistant that above-mentioned 2 yuan of systems by use introducing CuO or 3 yuan of system combinations constitute and the fusing assistant manufacturing that formed separately by CuO are with the monocrystal thin films of Bi as constituent, can in wide range, make the smooth film that does not have defective, dislocation, and can make and have excellent crystalline film.
In addition, carrying out the large volume monocrystalline by flux method when growing up, with the mixed combination of raw material and fusing assistant as above-mentioned Bi 2O 3-TiO 22 yuan of systems or Bi 2O 3-TiO 2During 3 yuan of system combinations of-CuO, CuO is used as catalyzer in oxide monocrystal is grown up, the crystallinity of controlled oxidation thing monocrystalline, and can play the effect of the Bi evaporation that prevents that vapour pressure is high.
Just, crystallizing in the regular way of use fusing assistant of the present invention, it all is important that all raw materials during the beginning crystalline growth are formed (primary crystal zone), when making film, the above-mentioned primary crystal zone that consists of, when being the large volume monocrystalline, what contain raw material and fusing assistant consists of the primary crystal zone.
As mentioned above, the method according to this invention making the manufacture method of bismuth-containing as the multielement oxide monocrystal that constitutes element, is applicable to the manufacturing of the oxide monocrystal of film and large volume, can make the monocrystalline of crystallinity excellence, and pass through to use Bi as fusing assistant 2O 3The 2 yuan of systems of-CuO or Bi 2O 3Bi can be made and use to 3 yuan of system combinations of-CuO-TiO or use CuO can reduce the consumption of environmentally harmful Bi separately 2O 3Has equal crystalline monocrystalline during separately as fusing assistant.
Description of drawings
Fig. 1 is in manufacture method of the present invention, the Bi of the composition that fusing assistant during film stack or the raw material when the large volume monocrystalline made and fusing assistant combination obtain 2O 3-CuO-TiO class 3 metasystem composition diagrams.Fig. 2 is the synoptic diagram of the device of the pulse laser method of piling of use in embodiment 1 and the comparative example 1.Fig. 3 is the synoptic diagram of the device of the flux method of use in embodiment 2 and the comparative example 2.Fig. 4 be expression based on the configuration of surface observations of the AFM of embodiment 1 (right side) and comparative example 1 (left side) for the accompanying drawing photograph.Fig. 5 be the XRD figure case of embodiment 1 and comparative example 1 comparison diagram (on: 2 θ-θ, down (00 14) oscillating curve at peak).Fig. 6 be expression embodiment 2 (right side) and comparative example 2 (left side) monocrystalline face shaping observations for accompanying drawing optics photograph.Fig. 7 be expression embodiment 3 (right side) and comparative example 3 (left side) monocrystal thin films face shaping observations for accompanying drawing AFM photograph.Fig. 8 be embodiment 3 (descending) and comparative example 3 (on) monocrystal thin films face shaping observations for accompanying drawing TEM photograph.
Embodiment
In Fig. 1, be illustrated in the manufacture method of the present invention the Bi of the composition that fusing assistant during film stack or the raw material when the large volume monocrystalline made and fusing assistant combination obtain 2O 3-CuO-TiO class 3 metasystem composition diagrams.As shown in Figure 1, this is formed with molar ratio computing, is 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 scope.Bi 2O 3Fusing point be 850 ℃, the fusing point of CuO is 1200 ℃.Sneak into many more CuO, fusing point is just high more.At CuO/Bi 2O 3Less than 2 o'clock, fusing point was smaller or equal to 1000 ℃, and during as the use of fusing assistant, if greater than this scope, then fusing point uprises, is difficult to form liquid, so be difficult to use as fusing assistant.Preferred scope is, with molar ratio computing, is 0＜CuO/Bi 2O 3＜4/3.
In addition, as general formula (Bi 2O 2) A M-1B mO 3m+1The bismuth-containing multielement oxide compound of the forceful electric power dielectric material shown in (A=Sr, Ba, Ca, Bi etc., B=Ti, Ta, Nb) is to decompose the fusion compound, so can only separate out from the more zone of Bi.In addition, according to Bi 2O 3-TiO 2If state graph is TiO/Bi 2O 3Greater than 7/6, Bi then 2Ti 2O 7, Bi 2Ti 4O 11And TiO 2Separate out, so not preferred.Preferred scope with molar ratio computing, is 0≤TiO/Bi 2O 3＜9/8.
The basic working procedure of using in the method for the present invention is described.The accumulation of fusing assistant layer, the accumulation of crystal seed layer, all be identical as the accumulation of the monocrystal thin films layer of target, can use common pulse laser to pile up (PLD) method, spatter method, MBE method, mocvd method etc., but hereinafter, to using the situation of PLD method, at length be described based on Fig. 2.
As the device of the known various structures of film deposition system of using the PLD method, all be fit to use in the method for the invention.Film deposition system is that single crystal substrate 1 is remained on the chamber interior that can vacuumize, and the 2 pairs of substrates 1 of well heater by its inner face side heat.Target is placed in the chamber, makes the outer KrF laser of chamber 3 irradiation targets 4,5,6, make the target surface evaporation.Target when piling up as single crystalline layer can use have the composition identical with the ferroele ctric oxide compound of film forming purpose, the polycrystalline sintered compact of structure.The steam 7 of target arrives substrate 1, piles up on the substrate 1 of heating by the fusing assistant layer.
Gas introduction port 8 is set in chamber, can supply oxygen to regulate the oxygen partial pressure in the chamber.In the PLD method, usually, in evaporation, with O 2, O 3Introduce in the chamber film oxidation in the time that film forming can being made Deng oxidizing gas.
The object lesson of this device for example, is opened flat 7-267791 communique, spy the spy and is opened in the flat 5-43390 communique open.The former places substrate above in chamber, below relatively place target with substrate, the example of oxygen introducing port is set near the substrate.The latter's be oxygen around substrate mobile example abreast.Can use SrTiO as substrate 1 3(001) substrate, Si substrate, Al 2O 3Substrate, LaAlO 3Substrate, MgO substrate, NdGaO 3Substrate etc.
Method of the present invention is applicable to that manufacturing is with Bi 4Ti 3O 12, Bi 4BaTi 4O 15, Bi 4SrTi 4O 15, Bi 4CaTi 4O 15, SrBi 2Ta 2O 9Or SrBi 2Nb 2O 9Deng with Bi 2O 3As the oxide monocrystal material of fusing assistant use, below, specify for example and make Bi 4Ti 3O 12The situation of monocrystal thin films.
Below be expressed as follows operation: piling up with molar ratio computing on substrate in advance is 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The fusing assistant that 3 yuan of system combinations of-CuO-TiO form is piled up monocrystal thin films by this fusing assistant accumulation horizon then on substrate.
At first, as first operation, be away from operating stepper-motor, the selection target from the outside.Under the situation of a plurality of targets, select Bi respectively 4Ti 3O 12And Bi 2O 3, the target formed of CuO, change the laser energy or the umber of pulse of ablating, ablating to form with molar ratio computing respectively is 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 33 yuan of system combinations of-CuO-TiO.Under single target situation, use after using the material be fabricated to above-mentioned compositing range.In addition, can on substrate 1, pile up the crystal seed layer that the composition as the single crystal film of target forms in advance.First operation preferably press at oxygen be in the oxygen atmosphere about 10～400Pa, substrate temperature is to carry out under about 400～600 ℃.
As second operation, be that substrate temperature is risen.Preferably press at oxygen be in the oxygen atmosphere about 10～70Pa, substrate temperature is not for making the temperature of fusing assistant layer evaporation, just about 650～750 ℃.
As the 3rd operation, be to use Bi 4Ti 3O 12As target, by the fusing assistant layer by Bi 4Ti 3O 12Steam the gas phase seed of target oxide compound is piled up, form high-quality film.Film is made under the vacuum of the pressure of the oxygen about 10～70Pa degree, so under this condition, the fusing assistant layer almost becomes liquid.After film forming finished, fusing assistant was separated out with the form of drop to the surface, can remove by the etching of 5%HCl solution.
In addition, after piling up the fusing assistant form by CuO on the substrate, by this fusing assistant accumulation horizon with Bi 6Ti 3O xThe Bi-Ti-O that forms is fed on the substrate, makes Bi 4Ti 3O 12The oxide monocrystal film time, the excessive composition of Bi uses as fusing assistant, finally plays the purposes of Bi-Cu-O fusing assistant.This method is to make the SrBi that does not contain the Ti composition 2Ta 2O 9, Bi 2Si 2CaCu 2O 8Deng the preferred method of monocrystal thin films.
After piling up the fusing assistant form by CuO on the substrate, by this fusing assistant accumulation horizon with Bi 6Ti 3O xThe Bi-Ti-O that forms is fed on the substrate, makes Bi 4Ti 3O 12The operation of oxide monocrystal film as follows.
As first operation, be the target of selecting CuO to form, ablating forms the fusing assistant layer.Oxygen in the chamber is pressed and is preferably about 800～1300Pa, and substrate temperature is preferably 750～850 ℃.Can on substrate, pile up crystal seed layer in advance.The crystallinity of finding the amount of CuO fusing assistant and monocrystal thin films all has the trend of raising, can pile up for thickness 10nm or more than, be preferably 20nm or more than.
As second operation, use with target film and form the Bi that compares the Bi surplus 6Ti 3O 12～Bi 8Ti 3O 12As target, pile up Bi 4Ti 3O 12Oxide compound.Get final product identical of pressure in the chamber with first operation.Under the vacuum that the oxygen about 800～1300Pa is pressed, make film, so the fusing assistant layer is almost liquid under this condition.In addition, in the method, remain in the most surperficial fusing assistant after monocrystalline is grown up and also can remove by the ultrasonic washing that uses HCl solution.
Can use spatter method as chemical vapour deposition of the present invention.Described spatter method is that the energetic ion that will produce in the plasma body incides in the target, flies on the substrate by the atom that makes the target that inspires from here, and film crystal is grown up.As control Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 3The method of the composition of the fusing assistant layer that 3 yuan of system combinations of-CuO-TiO form, when single target, the manufacturing mol ratio is 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 composition when a plurality of target, is regulated and is drenched the Bi that spatters respectively 4Ti 3O 12And Bi 2O 3, CuO the ratio of target, perhaps regulate the time that substrate passes through on each target.
Can be with chemical vapour deposition of the present invention as chemical vapor deposition method (CVD) method.Described chemical vapor deposition method is to prepare as the high organo-metallic molecule of vapour pressure constituting element, and this molecule is arrived the film growth chamber by gas delivery such as argons.Organic molecule decomposes on substrate, and organic molecule flies away from, and has only metallic element to stay on the substrate film growth.
In order to regulate the flow of each the organo-metallic molecule that constitutes element, can regulate the temperature of vapor molecule container, perhaps regulate the pipeline valve that molecule passes through.In the film deposition system of said structure, the switching of the supply line valve separately of the organo-metallic molecule by regulating multiple element respectively can be supplied element arbitrarily.
Also can use chemical vapour deposition of the present invention as molecular beam epitaxy (MBE) method.Molecular beam epitaxy is to use the effusion cell (Effusioncell) that is used to produce the atom fusing assistant, supplies bismuth, titanium, copper etc. respectively independently and constitutes element.For the high element of fusing point, also can use electron beam gun hot type element.The switching of the gate on the temperature that the amount of atom fusing assistant can be by element, the output of electron beam gun, element top is regulated.
Then, to making large volume Bi 4Ti 3O 12The example of monocrystalline describes.Can use the high-temperature electric resistance furnace that is warmed up to 1500 ℃, the platinum crucible that is used to add raw material and fusing assistant as the employed device of flux method.As shown in Figure 3, be out of shape in order to prevent platinum crucible 11, and put it in the alumina crucible 12, between two crucibles, insert aluminum oxide powder 13.The cultivation raw material and the fusing assistant of oxide monocrystal are mixed fully, so that ratio of components is counted 0＜CuO/Bi with mole 2O 3＜2,0≤TiO/Bi 2O 3＜7/6.Mol ratio when just, beginning crystalline growth is 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6.
This raw material+fusing assistant 14 is put into platinum crucible 11, in electric furnace, be heated to 1250 ℃.It is reported 1250 ℃ of normally Bi under 1 normal atmosphere 4Ti 3O 12The temperature that begins to fuse.Under this temperature, kept 12 hours, then, from about 3 ℃/hour～12 ℃/hour cooling of speed slowly.For example, in 120 hours, slowly be cooled to 900 ℃, produce the nucleus of target, cultivate crystallization.Use kind of a crystalline substance to grow up.With 6 hours from 900 ℃ of cool to room temperature.Usually, in this flux method, after cultivating crystal, also fusing assistant can residually be arranged.Can be by in platinum crucible, injecting the solution of acid such as nitric acid, isolate monocrystalline from fusing assistant after, take out from crucible.When fusing assistant is insoluble, can heating crucible fusing assistant be dissolved in nitric acid mutually, obtain the monocrystalline phase.
Embodiment
Embodiment 1
Use common pulse laser method of piling to make Bi 4Ti 3O 12The ferroele ctric film.Target when piling up as the sull that is used to form the fusing assistant layer uses ratio of components to be Bi: Ti=2: the sintered compact (Bi of 1 mixed powder and CuO powder 2O 3: Ti 2O 3: CuO=27: 27: 2).In addition, as with Bi 4Ti 3O 12The target of ferroele ctric forming thin film can be with Bi 2O 3, TiO 2Powder is adjusted to aforementioned target to be formed, and is heated to 700 ℃ in common electric furnace, uses the material of heating gained.
As first operation, use the pulse laser piling apparatus, and use SrTiO 3(100) as substrate.The selection of target is to be undertaken by stepper-motor from outside remote manipulation.On substrate, pile up Bi by pulse laser 2TiO x, so that thickness is 0.9nm, target is changed into CuO, pile up CuO so that thickness is 0.1nm., pile up altogether 20 times as 1 cycle with this, forming thickness is the fusing assistant layer of 20nm.By the thickness that made for 1 cycle is 1nm, can form to sneak into the fusing assistant layer that atom level is formed on film thickness direction.The condition of first operation is: substrate temperature is 500 ℃, and oxygen partial pressure is 70Pa, and the KrF excimer laser is output as 1.8J/cm 2, frequency is 10Hz.
Then, be in 10 minutes, substrate temperature to be risen to 700 ℃ as second operation.Kept 10 minutes down at 700 ℃ then.
Be to use Bi as the 3rd operation 4Ti 3O 12The target of forming is piled up Bi according to following condition on the fusing assistant layer 4Ti 3O 12Film.Film thickness is 500nm.The condition of the 3rd operation is: stackeding speed is 8nm/ minute, and the accumulation time is 60 minutes, and substrate temperature is 700 ℃, and oxygen partial pressure is 70Pa, and the KrF excimer laser is output as 1.8J/cm 2, frequency is 10Hz.
Bi to the c axle orientation made 4Ti 3O 12Film uses AFM to observe configuration of surface, uses XRD to carry out crystallinity when estimating, and shown in Fig. 4 (right side), in AFM, the step/hierarchic structure of half height of c axial length that is equivalent to unit lattice is the smooth of atom level in wide region by splendid demonstrating.In addition, as shown in Figure 5, in RXD, compare with the film of common PLD method manufacturing, the half-width from 0.148 to 0.076 at (0014) peak has had very large raising.
Comparative example 1
Use Bi 4Ti 3O 12Target when piling up as the fusing assistant layer of embodiment 1.This composition does not contain CuO.The thickness of fusing assistant layer is 20nm.Other condition is identical with embodiment 1, makes Bi 4Ti 3O 12Film.Owing to do not have Ti and Cu in the fusing assistant layer, so, be the film of crystallinity difference as Fig. 4 (right side) and shown in Figure 5.
Embodiment 2
Total composition of raw materials weighing and fusing assistant is Bi with the molar ratio computing respectively 2O 3: TiO 2: CuO=10: 3: 1 powder, so that total amount is 80g.Then, join in the agate mortar and stir.At this moment, put into ethanol, with the powder uniform mixing.After ethanol has been done, powder is put into platinum crucible (35ml size).This platinum crucible is put into alumina crucible, between two crucibles, insert alumina powder.
Put into electric furnace, be heated to 1250 ℃ with 4 hours, placed 12 hours down at 1250 ℃.Then, spend 120 hours and slowly cool to 900 ℃.Then, with 6 hours, cool to room temperature from 900 ℃.Then, dropped to room temperature with 6 hours from 900 ℃ of cooling degree.Monocrystalline covers with fusing assistant, owing to do not separate from platinum alloy crucible, uses concentrated nitric acid, dissolving fusing assistant phase.
In Fig. 6 (right side), the expression gained the large volume monocrystalline face shaping observations for accompanying drawing optics photograph.Although add all 7mol% of powder by Bi 4Ti 3O 12The copper of the impurity that formation obtains, but shown in Fig. 6 (right side), can cultivate into minimizing Bi 2O 3The large volume monocrystalline of the non-patent literature 2 disclosed same levels sizes (about 1cm) of the fusing assistant of amount.
Comparative example 2
Weighing Bi 2O 3Amount than embodiment more than 2, do not contain CuO and Bi 2O 3: TiO 2The powder of=11: 3 mol ratio is 80g altogether.Then, adding agate mortar stirs.At this moment, add ethanol, make powder even.After ethanol has been done, powder is put into platinum crucible (35ml size).This platinum crucible is put into alumina crucible, between crucible, insert alumina powder.
Put into electric furnace and be heated to 1250 ℃, placed 12 hours down at 1250 ℃ with 4 hours.Then, spend 120 hours temperature slowly is reduced to 900 ℃.Then, with 6 hours, temperature is reduced to room temperature from 900 ℃.Monocrystalline is covered by fusing assistant, adheres on the platinum crucible.Use concentrated hydrochloric acid, dissolving fusing assistant phase obtains monocrystalline.
In Fig. 6 (left side), use the face shaping observations of representing the large volume monocrystalline of gained for accompanying drawing with the optics photograph.As Fig. 6 (left side) as can be known, can turn out large volume monocrystalline with non-patent literature 2 disclosed same levels sizes (about 1cm).
Embodiment 3
Use common pulse laser method of piling to make Bi 4Ti 3O 12The dielectric material film.As film forming is Bi 4Ti 3O 12The target of ferroele ctric film uses the target identical with embodiment 1.Target when the CuO fusing assistant is piled up uses the CuO sintered powder.At substrate temperature is that 800 ℃, oxygen partial pressure are that 800Pa, KrF excimer laser are output as 1.8J/cm 2, frequency is under the condition of 10Hz, piles up Bi on substrate 2TiO xAs crystal seed layer, thickness is 20nm, with the SrTiO of being piled into like this 3(100) use as substrate.
Being to use CuO as target as first operation, is that 800 ℃, oxygen partial pressure are that 800Pa, KrF excimer laser are output as 1.8J/cm at substrate temperature 2, frequency is under the condition of 10Hz, piles up CuO on crystal seed layer, thickness is 20nm.
Be to use Bi as second operation 6Ti 3O xThe target of forming is that 800 ℃, oxygen partial pressure are that 800Pa, KrF excimer laser are output as 1.8J/cm at substrate temperature 2, frequency is that 10Hz, stackeding speed are that 8nm/ minute, accumulation time are under 60 minutes the condition, accumulating film on CuO fusing assistant layer.Compare Bi 4Ti 3O 12Form too much BiO and use, separate out on the surface as the CuO-BiO fusing assistant.Thus, form Bi 4Ti 3O 12Film.The thickness of film is 300nm.Remain in Bi 4Ti 3O 12The most surperficial fusing assistant of film uses the HCl solution of 5Vol%, and ultrasonic washing was removed in 2 seconds.The film of gained is several microns oarse-grained Bi 4Ti 3O 12Single crystal film.
Comparative example 3
Except not using the CuO fusing assistant, under the condition identical with embodiment 1, accumulating film.In Fig. 7, the Bi that expression embodiment 3 (right side) and comparative example 3 (left side) are piled up 4Ti 3O 12The afm image of film surface.Do not use among Fig. 7 (left side) of CuO fusing assistant, under high magnification, can observe trickle tomography from the step substrate.On the other hand, in the Fig. 7 (right side) that uses the CuO fusing assistant, do not observe tomography, under wide region (5 microns angles), can obtain atomically flat film.The result of this AFM also can confirm by tem observation, from Fig. 8 (on) shown in the tomography of comparative example 3 observed step substrates, in the embodiment 3 shown in Fig. 8 (descending), disappear.
Industrial applicibility
Method conduct of the present invention is for the manufacture of not having defective Bi4Ti 3O 12Deng monocrystal thin films The manufacturing technology of material and large volume material is important, and these materials can be expected advancing In the baseplate material of one step build-up film and the unleaded fixedness ferroele ctric storage medium Practical.

Claims (6)

1. a bismuth-containing is as the manufacture method of the multielement oxide monocrystal that constitutes element, and it is characterized in that: pile up fusing assistant on substrate in advance, wherein fusing assistant is with mol ratio 0＜CuO/Bi 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 3The fusing assistant that 3 yuan of system combinations of-CuO-TiO constitute is piled up monocrystal thin films by this fusing assistant accumulation horizon on substrate.
2. a bismuth-containing is characterized in that as the manufacture method of the multielement oxide monocrystal that constitutes element: after piling up the fusing assistant that is made of CuO on the substrate, use to form with target film and compare the Bi of Bi surplus 6Ti 3O 12～Bi 8Ti 3O 12As target, by piling up Bi-Ti-O is supplied to this fusing assistant accumulation horizon, on substrate, form Bi simultaneously 4Ti 3O 12The single crystal film.
3. according to the manufacture method of claim 1 or 2 oxide monocrystals of putting down in writing, it is characterized in that: the accumulation of aforementioned fusing assistant and monocrystal thin films is undertaken by spatter method, MBE method, pulse laser method of piling or mocvd method.
4. according to the manufacture method of the oxide monocrystal of each record of claim 1～3, it is characterized in that: substrate is SrTiO 3(001) substrate, Al 2O 3Substrate, Si substrate, LaAlO 3Substrate, MgO substrate or NdGaO 3Substrate.
5. manufacture method that contains bismuth as the multielement oxide monocrystal that constitutes element, it is characterized in that: making the composition that contains raw material and fusing assistant is 0＜CuO/Bi with molar ratio computing 2O 3＜2,0≤TiO/Bi 2O 3＜7/6 Bi 2O 3The 2 yuan of systems of-CuO or Bi 2O 3The liquation that 3 yuan of system combinations of-CuO-TiO constitute with its cooling, is cultivated monocrystalline.
6. according to the manufacture method of the oxide monocrystal of each record of claim 1～5, it is characterized in that: bismuth-containing is Bi as the multielement oxide monocrystal that constitutes element 4Ti 3O 12, Bi 4BaTi 4O 15, Bi 4SrTi 4O 15, Bi 4CaTi 4O 15, SrBi 2Ta 2O 9Or SrBi 2Nb 2O 9
CNB2004800139273A 2003-05-21 2004-05-21 Method for producing single crystal of multi- element oxide single crystal containing bismuth as constituting element Expired - Fee Related CN100334262C (en)

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CN102140688A (en) * 2011-03-12 2011-08-03 陕西科技大学 Preparation method of Bi2O3 polycrystal
CN106362729A (en) * 2016-08-31 2017-02-01 中国科学院新疆理化技术研究所 In-situ preparation method of photocatalyst strontium bismuth niobium oxide containing oxygen vacancy defect
CN106902804A (en) * 2017-04-13 2017-06-30 上海理工大学 A kind of preparation method of laminated perovskite type strontium tantalum base ternary oxide photochemical catalyst
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CN1045658A (en) * 1989-03-16 1990-09-26 中国科学院上海冶金研究所 A kind of preparation method of metallic oxide superconduction film
CN1068214A (en) * 1991-06-26 1993-01-20 北京航空航天大学 The preparation bismuth is the new method (molten-salt reaction method) of superconducting oxide crystal
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CN102140688A (en) * 2011-03-12 2011-08-03 陕西科技大学 Preparation method of Bi2O3 polycrystal
CN102140688B (en) * 2011-03-12 2012-06-27 陕西科技大学 Preparation method of Bi2O3 polycrystal
CN106362729A (en) * 2016-08-31 2017-02-01 中国科学院新疆理化技术研究所 In-situ preparation method of photocatalyst strontium bismuth niobium oxide containing oxygen vacancy defect
CN106362729B (en) * 2016-08-31 2018-11-09 中国科学院新疆理化技术研究所 A kind of in-situ preparation method of oxygen-containing vacancy defect photochemical catalyst strontium bismuth niobium oxygen
CN106902804A (en) * 2017-04-13 2017-06-30 上海理工大学 A kind of preparation method of laminated perovskite type strontium tantalum base ternary oxide photochemical catalyst
CN111473956A (en) * 2019-01-24 2020-07-31 深圳市共进电子股份有限公司 Device and method for testing resolution of wide-angle lens
CN111473956B (en) * 2019-01-24 2022-04-15 深圳市共进电子股份有限公司 Device and method for testing resolution of wide-angle lens

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