CN1983464B - Ferroelectric film, ferroelectric capacitor, ferroelectric memory, piezoelectric element and semiconductor element - Google Patents

Abstract

A ferroelectric film is composed of an oxide represented by a general formula of AB1-xNbxO3. The component A comprises at least Pb, and the component B comprises at least one of Zr, Ti, wherein0.1 <= x <= 0.4.

Description

Strong dielectric film, ferro-electric materials capacitor, strong dielectric memory, piezoelectric element, semiconductor element

Female case of this division application is:

Denomination of invention: strong dielectric film, capacitor and their manufacture method, strong dielectric memory

International filing date: on October 23rd, 2003

International application no: PCT/JP03/13556

National applications number: 200380101906.2

Technical field

The present invention relates to the manufacture method of a kind of strong dielectric film, ferro-electric materials capacitor, strong dielectric memory, piezoelectric element, semiconductor element, strong dielectric film and the manufacture method of ferro-electric materials capacitor.

Background technology

In recent years, strong dielectric film such as PZT, SBT or use its research and development of ferro-electric materials capacitor, ferroelectric memory device etc. in vogue.The formation of ferroelectric memory device can roughly be divided into 1T type, 1T1C type, 2T2C type, simple matrix type.Wherein, because the 1T type structurally produces internal electric field in capacitor,, can not satisfy general 10 years of requiring of semiconductor and guarantee so confining force (data maintenance) is as short as 1 month.The formation of 1T1C type, 2T2C type and DRAM is roughly the same, selects to use transistor, the manufacturing technology of applicable DRAM in order to have.In addition, 1T1C type, 2T2C type are owing to the writing speed of having realized SRAM, so up to the present the following low capacity product of 256KB become commercialized.

Up to now, as strong dielectric material, mainly use Pb (Zr, Ti) O ₃(PZT).Under the situation of PZT, use Zr/Ti than being that mixing 52/48 or 40/60, rhombohedron crystalline substance and quadratic crystal exists regional and near composition.In addition, under the situation of PZT, elements such as using La, Sr, Ca also mixes.Using this zone is the reliability that needs most in order to ensure memory element.Though it is fine that the magnetic hysteresis shape is enriched the quadratic crystal zone of containing Ti, produces the Schottky disorder that ionic crystal structure causes.Therefore, it is bad to produce leak current characteristic or impression (imprint) characteristic (deformation extent of so-called magnetic hysteresis), is difficult to guarantee reliability.

On the other hand, the cell size of simple matrix type is littler than 1T1C type, 2T2C type, in addition, but the multiple stratification capacitor, so expect highly integrated, cost degradation.

In addition, with regard to simple matrix type ferroelectric memory device in the past, as disclosed in Japanese kokai publication hei 9-116107 communique etc.In the disclosure communique, disclose when when memory cell writes data, apply the driving method of 1/3 voltage that writes voltage to non-selection memory unit.

But, in this technology, the B-H loop of the ferro-electric materials capacitor that not concrete record action is essential.But in order to obtain the simple matrix type ferroelectric memory device of actual act, the good B-H loop of square is indispensable.As can be with it corresponding strong dielectric material, the quadratic crystal PZT that considers rich Ti is as candidate, but the same with 2T2C type strong dielectric memory with the 1T1C that has stated, reliability guarantee to become most important problem.

In addition, though the PZT quadratic crystal illustrates the hysteresis characteristic with square that is suitable for memory use, lack reliability and be not practical.It is the reasons are as follows.

At first, the PZT quadratic crystal film after the crystallization has following tendency, and even the Ti containing ratio is high more, and then leakage current intensity is high more.In addition, when carry out to+or-either party of direction only writes a secondary data, when heating remains on static impression test 100 degree back sense datas, so-called, at 24 hours (h) afterwards, the data that write of residue basically.These are to constitute the Pb of element and the substantive characteristics that Ti self has as the PZT of ionic crystallization with as PZT, and the major part that becomes the formation element is the greatest problem that the PZT quadratic crystal film of Pb and Ti formation has.This problem is big when the PZT perovskite is ionic crystallization, is the essential problem that PZT has.

Figure 44 is associated with the guide look of main energy that PZT respectively constitutes the combination of element.Known PZT contains oxygen vacancies more after crystallization.That is, according to Figure 44, prediction Pb-O PZT constitute in the element in conjunction with the energy minimum, simply cut off when burning till heating or during polarization reversal.That is, if overflow (effusion) Pb, then according to the neutral charge principle, O can overflow.

Then, when the heating of impression (imprint) test etc. kept, PZT respectively constituted element vibration and repeated stock, but that PZT constitutes in the element Ti is the lightest, and the vibratory impulse when keeping owing to high temperature is easily overflowed.Therefore, if effusion Ti, then according to the neutral charge principle, O can overflow.In addition, because the maximum valence mumber of Pb:+2, Ti:4 helps combination, outside effusion O, neutral charge is false.That is, PZT forms easily for easy two the anionic so-called Schottky disorders such as O of overflowing of 1 cation such as Pb and Ti.

Here, the principle that the damaged leakage current that causes of oxygen in the PZT crystallization produces is described.Figure 45 A～Figure 45 C is that explanation has the general formula of using ABO _2.5The figure that leakage current in the oxide crystallization of brown capillose (Brownmillerite) type crystal structure of expression produces.Shown in Figure 45 A, brown millerite type crystal structure is with respect to having the general formula of using ABO ₃The perovskite type crystal structure of the PZT crystallization of expression etc. has the damaged crystal structure of oxygen.In addition, shown in Figure 45 B, owing in brown millerite type crystal structure, be oxonium ion near the cation, be difficult to become the leakage current cause of increased so cation is damaged.But shown in Figure 45 C, oxonium ion is connected in series in PZT crystallization integral body, and when because the damaged and crystal structure of oxygen when becoming brown millerite type crystal structure, therefore leakage current also can increase.

In addition, except that the generation of above-mentioned leakage current, Pb and Ti damaged or follow its O damaged also to be so-called lattice defect, to constitute the reason of interfacial polarization shown in Figure 46.At this moment, in the PZT crystallization,, become the state that what is called applies drift potential, result, magnetic hysteresis displacement or minimizing polarity because the electric field that the polarization of strong dielectric forms can produce the anti-electric field that lattice defect causes.And temperature is high more, and this phenomenon centre more produces.

More than be the problem of the essence that has of PZT, in pure PZT, think to be difficult to address the above problem that up to the present, in the memory component of the PZT that uses quadratic crystal, being unrealized has the element of abundant characteristic.

In addition, with regard to strong dielectric memory, the crystalline state that contains the strong dielectric film in ferro-electric materials capacitor is one of key factor of decision device property.In addition, in the manufacturing process of strong dielectric memory, have the operation that forms interlayer insulating film or diaphragm, use the technology that produces a large amount of hydrogen.At this moment because strong dielectric film mainly forms by oxide, so by the hydrogen that produces in the manufacturing process reduced oxide, can cause the influence of not expecting to the characteristic of ferro-electric materials capacitor.

Therefore, in strong dielectric memory in the past, in order to prevent the characteristic degradation of ferro-electric materials capacitor, by covering ferro-electric materials capacitor with barrier films such as pellumina or aluminium nitride films, the reducing resistance of guarantee electric capacity.But these barrier films need the unnecessary zone of occupying when strong dielectric memory highly integrated, and in addition, from the productivity aspect, expectation utilizes simpler technology to make the method for strong dielectric memory.

Summary of the invention

The object of the present invention is to provide a kind of the containing can be to 1T1C, 2T2C and the simple matrix type strong dielectric memory of the ferro-electric materials capacitor with hysteresis characteristic of 1T1C, 2T2C and the arbitrary use of simple matrix type strong dielectric.In addition, another object of the present invention is to provide a kind of strong dielectric film and manufacture method thereof that is suitable for above-mentioned strong dielectric memory.And another purpose of the present invention is to provide a kind of piezoelectric element and semiconductor element that uses above-mentioned strong dielectric film.In addition, another purpose of the present invention is to provide the strong dielectric memory of a kind of ferro-electric materials capacitor that utilizes the easy technology that does not need barrier film to come the fully secured characteristic, its manufacture method and use ferro-electric materials capacitor.

A kind of strong dielectric film is by AB _1-xNb _xO ₃General formula represent, contain Pb at least as the A element, constitute by more than at least a among Zr, Ti, V, W, Hf and the Ta as the B element, wherein 0.1≤x≤0.4

Description of drawings

Fig. 1 is the express strong sectional view of dielectric capacitor of the pattern face of land.

Fig. 2 is that expression forms the flow chart that the PZTN film is used with spin-coating method.

Fig. 3 is the figure of P (polarization)-V (voltage) B-H loop of expression ferro-electric materials capacitor.

Fig. 4 A～Fig. 4 C is the figure of surface texture of the PZNT film of expression embodiment 1.

Fig. 5 A～Fig. 5 C is the crystalline figure of the PZNT film of expression embodiment 1.

Fig. 6 A～Fig. 6 C is the figure of the relation of the thickness of PZNT film of expression embodiment 1 and surface texture.

Fig. 7 A～Fig. 7 C is the thickness of PZNT film of expression embodiment 1 and the figure of crystalline relation.

Fig. 8 A～Fig. 8 C is the thickness of PZNT film of expression embodiment 1 and the figure of hysteresis characteristic.

Fig. 9 A～Fig. 9 C is the thickness of PZNT film of expression embodiment 1 and the figure of hysteresis characteristic.

Figure 10 A and Figure 10 B are the figure of leak current characteristic of the PZNT film of expression embodiment 1.

Figure 11 A is the figure of fatigue properties of the PZTN film of expression embodiment 1.Figure 11 B is the figure of static impression characteristic of the PZTN film of expression embodiment 1.

Figure 12 is that the ozone TEOS that utilizes of expression embodiment 1 forms SiO ₂The structure chart of the ferro-electric materials capacitor of diaphragm.

Figure 13 is that the ozone TEOS that utilizes of expression embodiment 1 forms SiO ₂The figure of the hysteresis characteristic of the ferro-electric materials capacitor after the diaphragm.

Figure 14 is the figure of leak current characteristic of the existing PZT film of expression embodiment 1.

Figure 15 is the figure of fatigue properties of ferro-electric materials capacitor of the existing PZT film of use of expression embodiment 1.

Figure 16 is the figure of static impression characteristic of ferro-electric materials capacitor of the existing PZT film of use of expression embodiment 1.

Figure 17 A and Figure 17 B are the figure of hysteresis characteristic of the PZTN film of expression embodiment 2.

Figure 18 A and Figure 18 B are the figure of hysteresis characteristic of the PZTN film of expression embodiment 2.

Figure 19 A and Figure 19 B are the figure of hysteresis characteristic of the PZTN film of expression embodiment 2.

Figure 20 is the figure of X-ray diffraction pattern of the PZTN film of expression embodiment 2.

Figure 21 is the damaged amount of Pb in the PZTN crystallization of expression embodiment 2 and the graph of a relation of the ratio of components of Nb.

Figure 22 is the WO of explanation as the perovskite crystallization ₃The figure of crystal structure.

Figure 23 A～Figure 23 C is the sectional view of the formation operation of the PZTN film among the pattern ground expression embodiment 3.

Figure 24 A and Figure 24 B are the figure of variation of the lattice constant of the PZTN film of explanation among the embodiment 3.

Figure 25 is PZTN film and the lattice of Pt metal film the do not match figure of variation of rate of explanation among the embodiment 3.

Figure 26 is that expression utilizes spin-coating method to form the flow chart that the existing PZT film in the reference example is used.

Figure 27 A～Figure 27 E is the figure of the surface texture of the PZT film in the expression reference example.

Figure 28 A～Figure 28 E is the crystalline figure of the PZT film in the expression reference example.

Figure 29 A and Figure 29 B are the figure of the magnetic hysteresis of the quadratic crystal PZT film in the expression reference example.

Figure 30 is the figure of the magnetic hysteresis of the existing quadratic crystal PZT film in the expression reference example.

Figure 31 A and Figure 31 B are the figure of the degassing analysis result of the quadratic crystal PZT film in the expression reference example.

Figure 32 A～Figure 32 C is the figure of the manufacturing process of expression ferro-electric materials capacitor.

Figure 33 A and Figure 33 B are the figure of the hysteresis characteristic of expression ferro-electric materials capacitor.

Figure 34 is the figure of the electrical characteristics of expression ferro-electric materials capacitor.

Figure 35 A is the plane graph of the ferroelectric memory device of pattern ground expression simple matrix type.Figure 35 B is the sectional view of the ferroelectric memory device of pattern ground expression simple matrix type.

Figure 36 is the sectional view that expression is integrated in memory cell array and peripheral circuit one example of the ferroelectric memory device on the same substrate jointly.

Figure 37 A is the sectional view of pattern ground expression 1T1C type strong dielectric memory.Figure 37 B is the equivalent circuit diagram of pattern ground expression 1T1C type strong dielectric memory.

Figure 38 A～Figure 38 C is the figure of the manufacturing process of expression strong dielectric memory.

Figure 39 is the exploded perspective view of recording head.

Figure 40 A is the plane graph of recording head.Figure 40 B is the sectional view of recording head.

Figure 41 is the sectional view of the layer structure of pattern ground expression piezoelectric element.

Figure 42 is the schematic diagram of expression inkjet recording device one example.

Figure 43 A is the figure that is illustrated in the hysteresis characteristic of the strong dielectric film that adds Ta among the PZT.Figure 43 B is the figure that is illustrated in the hysteresis characteristic of the strong dielectric film that adds W among the PZT.

Figure 44 is each performance plot of combination that expression is associated with the formation element of PZT class strong dielectric.

Figure 45 A～Figure 45 C is the figure of the Schottky disorder of the brown millerite type crystal structure of explanation.

Figure 46 is the figure of the interfacial polarization of explanation strong dielectric.

Embodiment

(1) strong dielectric film of present embodiment is by AB _1-XNb _XO ₃General formula represent that the A element is made of Pb at least, the B element constitutes by more than at least a among Zr, Ti, V, W, Hf and the Ta, the scope in 0.05≤x＜1 contains Nb.

In addition, the A element can be by Pb _1-yLn _y(0＜y≤0.2) constitutes.In addition, Ln can constitute by more than at least a among La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and the Lu.

(2) strong dielectric film of present embodiment is by (Pb _1-yA _y) (B _1-xNb _x) O ₃General formula represent, the A element constitutes by more than at least a among La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and the Lu, the B element is by more than one constitute among Zr, Ti, V, W, Hf and the Ta, and the scope of (preferably 0.1≤x≤0.3) contains Nb in 0.05≤x＜1.

(3) strong dielectric film of present embodiment is following PZT class strong dielectric film, and it is many that Ti ratio of components Zr forms, and during Ti formed 2.5 moles more than the %, (preferably 10 moles of % are above below 30 moles) below 40 moles is replaced as Nb.In addition, this PZT class strong dielectric film can have at least a crystal structure of tetragonal system and rhombohedral system.And this PZT class strong dielectric film can contain Si or the Si and the Ge of 0.5 mole of % above (being more preferably more than 0.5 mole of %, less than 5 moles of %).In addition, this PZT class strong dielectric film can use sol gel solution to form.

(4) strong dielectric film of present embodiment is following PZT class strong dielectric film, by ABO ₃General formula represent, contain the formation element that Pb is used as the A side, contain the formation element that Zr and Ti are used as the B side at least.The damaged amount of Pb of A side is than described ABO in this PZT class strong dielectric film ₃The chemistry amount theoretical form at most also 20 moles below the %.This strong dielectric film contains Nb with 2 times ratio of components of the damaged amount of Pb that is equivalent to described A side in the B side.In this strong dielectric film, the Ti ratio of components Zr of B side forms high, and can have the crystal structure of rhombohedral system.In addition, this strong dielectric film can use sol gel solution to form.

(5) manufacture method of the strong dielectric film of present embodiment is the manufacture method of PZT class strong dielectric film, uses and mixes PbZrO ₃With sol gel solution, PbTiO ₃With sol gel solution and PbNbO ₃With the solution of sol gel solution as described sol gel solution.

In the manufacture method of the strong dielectric film of present embodiment, can use further mixing PbSiO ₃With the solution of sol gel solution as described sol gel solution.

(6) manufacture method of the strong dielectric film of present embodiment is the manufacture method of PZT class strong dielectric film, form under 1 the situation of being made as will be as the chemistry amount of the Pb of the formation element of A side theoretical, use the sol gel solution that contains Pb in 0.9～1.2 scope to form.

(7) manufacture method of the strong dielectric film of present embodiment can contain form described PZT class strong dielectric film on the metal film that is made of the platinum metals.

(8) in the manufacture method of the strong dielectric film of present embodiment, described platinum metals be Pt and Ir at least any.

(9) strong dielectric memory of present embodiment contains and the 1st electrode that is formed at the conducting of one of transistorized source electrode of CMOS on the Si wafer or drain electrode in advance, be formed at the strong dielectric film on described the 1st electrode, be formed at the 2nd electrode on the described strong dielectric film, by described the 1st electrode, the CMOS transistor that the electric capacity utilization that described strong dielectric film and described the 2nd electrode constitute is formed on the Si wafer is in advance selected action, wherein, described strong dielectric film is that quadratic crystal PZT more than 50% constitutes by the Ti ratio, 5 moles of above 40 moles of % of % were following by the Nb displacement during Ti formed, simultaneously by contain 1 mole more than the % Si and the strong dielectric film of Ge constitute.

(10) strong dielectric memory of present embodiment contains the 1st electrode of prior formation, along the 2nd electrode of arranging with the direction of described the 1st electrode crossing, at least be configured in the strong dielectric film in the intersection region of described the 1st electrode and described the 2nd electrode, by described the 1st electrode, the electric capacity that described strong dielectric film and described the 2nd electrode constitute is configured to rectangular, wherein, described strong dielectric film is that quadratic crystal PZT more than 50% constitutes by the Ti ratio, 5 moles of above 40 moles of % of % were following by the Nb displacement during Ti formed, simultaneously by contain 1 mole more than the % Si and the strong dielectric film of Ge constitute.

(11) manufacture method of the strong dielectric memory of present embodiment comprises: turning at the coating post crystallization is the PbZrO of the 1st material solution ₃Form with sol gel solution, as the PbTiO of the 2nd material solution ₃Form with sol gel solution, as the PbNbO of the 3rd material solution ₃Form with sol gel solution and PbSiO as the 4th material solution ₃Form operation with sol gel solution, described the 1st, the 2nd and the 3rd material solution is the material liquid that forms strong dielectric layer usefulness, and the 4th material solution is to generate the material liquid that normal dielectric layer with indispensable catalyst effect when the 1st, the 2nd and the 3rd material solution formed the strong dielectric layer is used.

(12) manufacture method of the ferro-electric materials capacitor of present embodiment comprises: form the operation of lower electrode on the fixed matrix; On described lower electrode, form by the operation that contains the strong dielectric film that Pb, Zr, Ti and Nb constitute as the PZTN composite oxides that constitute element; On described strong dielectric film, form the operation of upper electrode; Form diaphragm, to cover the operation of described lower electrode, strong dielectric film and upper electrode; At least after forming described diaphragm, be used for the heat treated operation that the described PZTN composite oxides of crystallization are used.

According to present embodiment, as the material of strong dielectric film, use and contain Pb, Zr, Ti and Nb as the PZTN composite oxides that constitute element, after forming diaphragm, carry out the crystallization of this PZTN composite oxides.Therefore, even if hypothesis when forming diaphragm, the infringement of the hydrogen that produces in being subject to processing of strong dielectric film, also can be by after this carrying out the heat treatment that crystallization is used, when recovering this infringement, crystallization PZTN composite oxides.Therefore, can omit and form the processing that the protection strong dielectric film is not subjected to the barrier film that reduction reaction uses in the past like that, can realize the reduction of productive raising and production cost.

(13) in the manufacture method of the ferro-electric materials capacitor of present embodiment, described strong dielectric film is implemented interim heat treatment under oxidizing atmosphere when forming, before the heat treatment of carrying out the described PZTN composite oxides of crystallization, become noncrystalline state.

According to this mode, before the crystallization strong dielectric film, become noncrystalline state.Therefore, in the strong dielectric film of this mode, can before forming diaphragm, prevent a deterioration of the crystalline quality that boundary's diffusion causes by noncrystalline state.In addition, the strong dielectric film of noncrystalline state is owing to implement interim heat treatment under oxidizing atmosphere, so import oxygen in film.Therefore, when the heat treatment that crystallization is used, can not rely on the crystallization that the gaseous species that contains in the atmosphere carries out the PZTN composite oxides.

(14) in the manufacture method of the ferro-electric materials capacitor of present embodiment, described diaphragm is a silicon oxide film, can use three monosilanes to form.

According to this mode; compare with the general tetraethyl orthosilicate of using (TEOS) in the formation silicon oxide film; owing to use few three monosilanes (TMS) of hydrogen amount that produce in the processing to form the diaphragm that constitutes by silicon oxide film, so can reduce the infringement that the reduction reaction to strong dielectric film causes.

(15) in the manufacture method of the ferro-electric materials capacitor of present embodiment, can in nonoxidizing atmosphere, carry out the heat treatment of the described PZTN composite oxides of crystallization.

According to this mode, owing in nonoxidizing atmosphere, carry out the heat treatment that crystallization is used, even if, can prevent that also peripheral components is subjected to the oxidative damage that high-temperature heat treatment causes so for example contain in the device of work in-process under the situation of peripheral components (for example metal wiring) outside the electric capacity etc.

(16) ferro-electric materials capacitor of present embodiment uses the manufacture method of above-mentioned ferro-electric materials capacitor to form.

(17) in addition, the strong dielectric film of present embodiment and ferro-electric materials capacitor are applicable in the strong dielectric memory, piezoelectric element and the semiconductor element that use it.

Below, describe preferred forms of the present invention in detail with reference to accompanying drawing.

1, strong dielectric film, ferro-electric materials capacitor and manufacture method thereof

Fig. 1 is the sectional view of the ferro-electric materials capacitor 100 of the pattern ground expression strong dielectric film 101 that uses embodiments of the present invention.

As shown in Figure 1, ferro-electric materials capacitor 100 is made of strong dielectric film the 101, the 1st electrode 102 and the 2nd electrode 103.

The 1st electrode 102 and the 2nd electrode 103 constitute by the monomer of noble metals such as Pt, Ir, Ru or based on the composite material of described noble metal.When the element of strong dielectric during to the 1st electrode 102 and 103 diffusions of the 2nd electrode, interface portion at electrode and strong dielectric film 101 produces composition fluctuation (deviation), the square reduction of magnetic hysteresis is so require the 1st electrode 102 and the 2nd electrode 103 to have the indiffusible compactness of element of strong dielectric film.

In order to improve the compactness of the 1st electrode 102 and the 2nd electrode 103, for example adopt by the method for the heavy gas spatter film forming of quality, make the oxide of Y, La etc. disperse method etc. in the noble metal electrode.

Strong dielectric film 101 use by contain Pb, Zr, Ti forms as the PZT class strong dielectric that constitutes element.Especially in the present embodiment, this strong dielectric film 101 is characterised in that Pb (Zr, Ti, the Nb) O of employing doping Nb in the Ti side ₃(PZTN).

(ionic radius is close, and atomic radius is identical for Nb and Ti size.) roughly the same, weight is 2 times of Ti, also is difficult to the atom of overflowing even if impact between the atom that lattice vibration causes from lattice.In addition, the valence of Nb is stable when+5 valencys, even if effusion Pb also can utilize Nb ⁵⁺Compensate the valence mumber that Pb overflows.In addition, during crystallization, overflow, also because of the big O of effusion size, so the little Nb of size enters easily even if produce Pb.

In addition, because the valence of Nb also exists+4 valencys, so also can replace Ti ⁴⁺Fully carry out.In addition, in fact the total associativity of Nb is very strong, thinks that Pb also is difficult to overflow (H.Miyazawa, E.Natori, S.Miyashita; Jpn.J.Appl.Phys.39 (2000) 5679).

Up to now, mainly carry out in the territory, rhombohedron crystalline region at rich Zr, but its amount is few, is 0.2～0.025mol% (J.Am.Ceram.Soc, 84 (2001) 902 to PZT doping Nb; Phys.Rev.Let, 83 (1999) 1347) about.Like this, think and to mix that the main cause of a large amount of Nb is if for example add the Nb of 10 moles of % that then crystallized temperature can rise to more than 800 degree.

Therefore, when forming strong dielectric film 101, preferably also for example add PbSiO with the ratio of 1～5 mole of % ₃Silicate.Thus, the crystallization energy of PZTN is alleviated.That is, when using PZTN, can add PbSiO by when adding Nb as the material of strong dielectric film 101 ₃Silicate is realized the reduction of the crystallized temperature of PZTN.

Below, the example of film build method of the PZTN strong dielectric film 101 of the ferro-electric materials capacitor 100 be applicable to present embodiment is described.

PZTN strong dielectric film 101 can be prepared by heat treatment etc. the oxide junction crystallization that contains in these mixed liquors to be obtained by containing the mixed solution that Pb, Zr, Ti and Nb the 1st～the 3rd material solution one of at least constitutes.

As the 1st material solution, but in the formation metallic element of example PZTN strong dielectric phase, in order to form the PbZrO based on Pb and Zr ₃The perovskite crystallization under anhydrous state, has been dissolved the solution of condensation polymer in n-butanols equal solvent.

As the 2nd material solution, but in the formation metallic element of example PZTN strong dielectric phase, in order to form the PbTiO based on Pb and Ti ₃The solution of condensation polymer has been dissolved in the perovskite crystallization in n-butanols equal solvent under anhydrous state.

As the 3rd material solution, but in the formation metallic element of example PZTN strong dielectric phase, in order to form the PbNbO based on Pb and Nb ₃The solution of condensation polymer has been dissolved in the perovskite crystallization in n-butanols equal solvent under anhydrous state.

State the 1st, the 2nd and the 3rd material solution in the use, form for example by PbZr _0.2Ti _0.8Nb _0.2O ₃(PZTN) under the situation of the strong dielectric film 101 of Gou Chenging, can be by (the 1st material solution): (the 2nd material solution): recently the mixing of (the 3rd material solution)=2: 6: 2.

But, even if make this mixed solution direct crystallizationization, also essential high crystallized temperature when making PZTN strong dielectric film 101.That is, if mix Nb, then crystallized temperature can sharply rise, but under the temperature range of the following elementization of 700 degree because can not crystallization, so 5 moles of Nb more than the % are not used as the substitutional element of Ti in the past, can not obtain the zone of additive up to now.In addition, in containing the PZT quadratic crystal that Ti Duos than Zr, there is not example fully.This can be from list of references J.Am.Ceram.Soc, and 84 (2001) 902 or Phys.Rev.Let, 83 (1999) 1347 understandings such as grade.

Therefore, in the present embodiment, can by for example 1 mole in above-mentioned mixed solution, further add more than the %, under 5 moles of % of less than as the 4th material solution, for forming PbSiO ₃Crystallization, the solution of dissolving condensation polymer solves the problems referred to above in n-butanols equal solvent under anhydrous state.

That is by using the mixed solution of above-mentioned the 1st, the 2nd, the 3rd and the 4th solution, but can be crystallization under the temperature range of the elementization below 700 degree, at the crystallized temperature of PZTN.

Particularly, come film forming strong dielectric film 101 according to flow chart shown in Figure 2.Carry out a succession of operation expectation number of times such as mixed solution painting process (step ST11), ethanol removal operation～dry heat treatment process～degreasing heat treatment step (step ST12, step ST13), afterwards, burn till by crystallization annealing (step ST14), form strong dielectric film 101.

Condition example in each operation is shown below.

At first, on the Si substrate, cover electrode noble metals such as Pt, film forming lower electrode (step ST10).Then, carry out the coating (step ST11) of mixed liquor by rubbing methods such as spin-coating methods.Particularly, the mixed solution that on the Pt covered substrate, drips.For the solution that drips is flowed in whole of substrate, after being rotated with the 500rpm degree, rotating speed is reduced to below the 50rpm, rotated about 10 seconds.The dry heat treatment process is carried out (step ST13) under 150 degree～180 degree.Dry heat processing use hot plate under air atmosphere waits and carries out.Equally, in the degreasing heat treatment step, on the hot plate that remains on 300 degree～350 degree, under air atmosphere, carry out (step ST13).Crystallization is used burns till and uses hot short annealing (RTA) to wait in oxygen atmosphere to carry out (step ST14).

In addition, the thickness after burning till can be about 100～200nm.Then, after by formation upper electrodes such as sputtering methods (step ST15), with the crystallinity that forms the interface of the 2nd electrode and strong dielectric film and improve the strong dielectric film as purpose, the same when burning till, in oxygen atmosphere, use RTA etc. to carry out post annealed (step ST16), obtain ferro-electric materials capacitor 100.

Below, investigate the influence of the hysteresis characteristic of using 101 pairs of ferro-electric materials capacitors 100 of PZTN strong dielectric film.

Fig. 3 be pattern the figure of P (polarization)-V (voltage) B-H loop of ferro-electric materials capacitor 100 is shown.At first, when applying voltage+Vs, become amount of polarization P (+Vs), afterwards, when voltage becomes 0, become amount of polarization Pr.And, when voltage be-during 1/3Vs, amount of polarization become P (～1/3Vs).In addition, when voltage be-during Vs, amount of polarization becomes P and (Vs), when becoming voltage 0 once more, becomes amount of polarization-Pr.In addition, when voltage be+during 1/3Vs, amount of polarization become P (+1/3Vs) when voltage become once more+during Vs, amount of polarization return once more P (+Vs).

In addition, ferro-electric materials capacitor 100 also has following characteristic with regard to hysteresis characteristic.At first, temporarily apply voltage Vs and become amount of polarization P (+Vs) afterwards, apply-voltage of 1/3Vs, and become at 0 o'clock applying voltage, the track shown in the arrow A in the B-H loop tracking map 3, amount of polarization has stationary value PO (0).In addition, temporarily apply voltage-Vs and with amount of polarization become P (Vs) afterwards, apply+voltage of 1/3Vs, and become at 0 o'clock applying voltage, the track shown in the arrow B in the B-H loop tracking map 3, amount of polarization has stationary value PO (1).If the difference of this amount of polarization PO (0) and amount of polarization PO (1) is enough big, then can utilize described spy to open that disclosed driving method makes the action of simple matrix type ferroelectric memory device in the flat 9-116107 communique etc.

In addition, according to the ferro-electric materials capacitor 100 of present embodiment, can realize the raising, the raising of Pr of square of low temperatureization, the magnetic hysteresis of crystallized temperature.In addition, based on the raising of the square of the magnetic hysteresis of ferro-electric materials capacitor 100 driving by simple matrix type ferroelectric memory device is become important disturbance

Stability has significant effect.With regard to simple matrix type ferroelectric memory device,, do not change i.e. disturbance stability of characteristics so need under this voltage, polarize owing to apply ± voltage of 1/3Vs to the unit that writes, reads yet.In fact, the present application people finds in general PZT, when the stable state from polarization begins along making the direction of polarization reversal provide 10 ⁸During inferior 1/3Vs pulse, amount of polarization descends about 80%, but confirms the ferro-electric materials capacitor 100 according to present embodiment, then is the slippage below 10%.Therefore, if the ferro-electric materials capacitor 100 of present embodiment is applicable in the ferroelectric memory device, but practicability simple matrix type memory then.

Below, the specific embodiment of present embodiment is described.

[embodiment 1]

In the present embodiment, PZTN more of the present invention and PZT in the past.The film forming flow process is all used described Fig. 2.

If Pb: Zr: Ti: Nb=1: 0.2: 0.6: 0.2,1: 0.2: 0.7: 0.1 and 1: 0.3: 0.65: 0.05.That is, establish the Nb addition and be 5～20 moles of whole %.Here add 0～1% PbSiO ₃

Fig. 4 A～Fig. 4 C illustrates the surface texture of the film of this moment.In addition, when utilizing X-ray diffraction method to measure the crystallinity of this film, shown in Fig. 5 A～Fig. 5 C.Under the situation of 0% (nothing) shown in Fig. 5 A,, also only obtain normal dielectric pyrochlore (Pyrochlore) even if crystallized temperature rises to 800 degree.In addition, under the situation of 0.5% shown in Fig. 5 B, PZT mixes existence with pyrochlore.In addition, under the situation of 1% shown in Fig. 5 C, obtain the single-orientated film of PZT (111).In addition, crystallinity also is do not obtain up to now best.

Then, to adding 1%PbSiO ₃The PZTN film, after establishing thickness and being 120～220nm, shown in Fig. 6 A～Fig. 6 C and Fig. 7 A～Fig. 7 C, the crystallinity that is directly proportional with thickness is shown respectively.In addition, Fig. 6 A～Fig. 6 C is the electron micrograph of the surface texture under expression thickness 120nm～200nm, and Fig. 7 A～Fig. 7 C is the crystalline measurement result based on X-ray diffraction method of the PZTN film under expression thickness 120nm～200nm.In addition, shown in Fig. 8 A～Fig. 8 C and Fig. 9 A～Fig. 9 C, in thickness is the gamut of 120nm～200nm, obtain the good hysteresis characteristic of square.In addition, Fig. 9 A～Fig. 9 C is the enlarged drawing of the B-H loop of Fig. 8 A～Fig. 8 C.Especially shown in Fig. 9 A～Fig. 9 C, in this routine PZTN film, confirm that magnetic hysteresis is fully opened, and saturated under the low-voltage below the 2V.

In addition, with regard to leakage characteristics, shown in Figure 10 A and Figure 10 B, forming or thickness regardless of film, when applying 2V when saturated (), all is 5 * 10 ^-8～7 * 10 ^-9A/cm ², very good.

Then, measuring PbZr _0.2Ti _0.6Nb _0.2O ₃When the fatigue properties of film and static impression, shown in Figure 11 A and Figure 11 B, very good.Especially it is all very good that whether the fatigue properties shown in Figure 11 A use Pt in upper/lower electrode.

And, as shown in figure 12, attempt on the ferro-electric materials capacitor 600 of the PZTN strong dielectric film 603 that forms lower electrode 602, present embodiment on the substrate 601, upper electrode 604, forming SiO based on ozone TEOS ₂Film 605.Known PZT in the past is as the SiO that carries out based on ozone TEOS ₂When film formed, the hydrogen that produces from TEOS passed through top Pt, reduction PZT, complete not shown magnetic hysteresis, damage PZT crystallization.

But the PZTN strong dielectric film 603 of present embodiment does not worsen as shown in figure 13 substantially, keeps good magnetic hysteresis.That is, the reducing resistance of the PZTN strong dielectric film 603 of present embodiment is strong as can be known.In addition, in quadratic crystal PZTN strong dielectric film 603 of the present invention, when Nb does not surpass under the situation of 40 moles of %, corresponding to the addition of Nb, the magnetic hysteresis that obtains.

Then, for relatively, carry out the evaluation of PZT strong dielectric film in the past.As PZT in the past, establish Pb: Zr: Ti=1 respectively: 0.2: 0.8,1: 0.3: 0.7 and 1: 0.6: 0.4.Its leakage characteristics as shown in figure 14, Ti content increases more, then leakage characteristics worsens more, under the situation of Ti:80%, when applying 2V, becomes 10 ^-5A/cm ², be not suitable for memory application as can be known.Equally, fatigue properties as shown in figure 15, Ti content increases more, then fatigue properties worsen more.In addition, after impression, as shown in figure 16, sense data not basically as can be known.

From above embodiment as can be known, the PZTN strong dielectric film of present embodiment except that solve thought in the past the essence of PZT be the leakage current of reason increase and problem such as impression characteristic degradation, also no matter the kind of memory, the quadratic crystal PZT how structure will can not be used owing to above-mentioned reason are used for memory use.In addition, an also applicable material in the piezoelectric element purposes of not using quadratic crystal PZT owing to same reasons.

[embodiment 2]

In the present embodiment, with regard to the PZTN strong dielectric film, make the Nb addition be changed to 0.5,10,20,30,40 mole of % and come more intense dielectric property.For whole test specimens, add the PbSiO of 5 moles of % ₃Silicate.In addition, form strong dielectric film formation with raw material and add methyl succinate in sol gel solution, pH is made as 6 to constituting film.The film forming flow process is all used described Fig. 2.

Measure the hysteresis characteristic of the PZTN strong dielectric film of present embodiment shown in Figure 17～Figure 19.

Shown in Figure 17 A, be under 0 the situation at the Nb addition, the magnetic hysteresis that obtains sewing, but shown in Figure 17 B, when the Nb addition is 5 moles of %, obtain the high good hysteresis characteristic of insulating properties.

In addition, shown in Figure 18 A, strong dielectric property the Nb addition be 10 moles of % in the past, can't see variation basically.Be under 0 the situation, to sew at the Nb addition, can't see variation in the strong dielectric property though also have.In addition, shown in Figure 18 B, be under the situation of 20 moles of % at the Nb addition, obtain the extraordinary hysteresis characteristic of square.

But shown in Figure 19 A and Figure 19 B, when the Nb addition surpassed 20 moles of %, hysteresis characteristic changed greatly, confirmed to worsen.

Therefore, compare X-ray diffraction pattern, as shown in figure 20.At the Nb addition is under the situation of 5 moles of % (Zr/Ti/Nb=20/75/5), no change when (111) peak is with the PZT film that do not add Nb in the past, along with the Nb addition increases to 20 moles of % (Zr/Ti/Nb=20/60/20), 40 moles of % (Zr/Ti/Nb=20/40/40), (111) peak value is displaced to low angle side.That is, as can be known, no matter whether rich Ti is the quadratic crystal zone to the composition of PZT, and actual crystallization all becomes the rhombohedron crystalline substance.In addition, as can be known along with the variation of system of crystallization, strong dielectric property changes.

In addition, after adding 45 moles of %Nb, magnetic hysteresis is not opened, and can not confirm strong dielectric property (omitting diagram).

In addition, it is very high to have narrated PZTN film insulating properties of the present invention, but obtain here PZTN be insulator condition as shown in figure 21.

That is, the insulating properties of PZTN film of the present invention is very high, to be equivalent to 2 times ratio of components of the damaged amount of Pb, adds Nb to the Ti side.In addition, the perovskite crystallization is from as shown in figure 22 WO ₃Crystal structure as can be known, even if A side ion damaged 100% is also set up and WO ₃System of crystallization easily change.

Therefore, under the situation of PZTN,, control the damaged amount of Pb energetically by adding Nb, and crystallization control system.

It is also very effective in being applied to piezoelectric element that this point is expressed the PZTN film of present embodiment.Generally PZT is being applied under the situation of piezoelectric element the territory, rhombohedron crystalline region of using rich Zr to form.At this moment, Zr is abundant PZT is called the soft PZT of being.This means that crystallization is soft shown in literal.For example, be PZT though also in the ink jetting nozzle of ink-jet printer, use soft, because too soft, so in the too high ink of viscosity, can not apply ink pressure and extrude.

On the other hand, it is PZT firmly that the quadratic crystal PZT of rich Ti is called, and means firm and crisp.But in PZTN film of the present invention, in as hard class, but the artificially makes system of crystallization be varied to the rhombohedron crystalline substance.Wherein, can system of crystallization be changed arbitrarily, and, because that the PZT of rich Ti is the ratio dielectric constant of strong dielectric film is little, so available low-voltage is come driving element.

The ink jetting nozzle that for example untapped hard class PZT up to now can be used for thus, ink-jet printer.In addition, because Nb makes the PZT deliquescing, thus moderately hard, not crisp PZT can be provided.

At last, as mentioned above, in the present embodiment, not only add Nb, also can when adding Nb, add silicate, reduce crystallized temperature thus.

[embodiment 3]

In the present embodiment, for example from by as the ferro-electric materials capacitor of the memory cell part that constitutes strong dielectric memory for example constitute the Pt of electrode material of piezoelectric-actuator of ink jetting nozzle part of ink-jet printer or metal film that platinum metals such as Ir constitutes on, forms the viewpoint of the lattice match under the situation of PZTN film, studied the validity of use PZTN film.The platinum metals is under the situation of element application PZT class strong dielectric film, in the bottom film that becomes the crystalline orientation of determining strong dielectric film, still as the also useful material of electrode material.But, because both lattice match are insufficient, so with regard to element application, the fatigue properties of strong dielectric film become problem.

Therefore, the present application people is contained in the formation element of PZT class strong dielectric film by making Nb, develops the unmatched technology of improving between PZT class strong dielectric film and the platinum metals film of lattice.Figure 23 A～Figure 23 C illustrates the film formation process of the PZT class strong dielectric film of this moment.

At first, shown in Figure 23 A, prepare fixed substrate 11.As substrate 11, use the substrate that on the SOI substrate, forms the TiOx layer.In addition, as substrate 11, can from the substrate that material known constitutes, select suitable substrate to use.

Afterwards, shown in Figure 23 B, on substrate 11, for example use sputtering method, form the metal film (the 1st electrode) 102 that constitutes by PT, afterwards, shown in Figure 23 C, on metal film 102, form the PZTN film, as strong dielectric film 101.Material as forming the PZTN film for example can use sol gel solution.More specifically, use at mixing PbZrO ₃With sol gel solution, PbTiO ₃With sol gel solution and PbNbO ₃With further adding PbNbO in the solution of sol gel solution ₃Solution with sol gel solution.In addition, the PZTN film, owing in constituting element, contain Nb, so the crystallized temperature height.Therefore, reduce, preferably use and further added PbSiO in order to make crystallized temperature ₃Solution with sol gel solution.In the present embodiment, utilize spin-coating method that above-mentioned sol gel solution is coated on the Pt metal film 102, carry out after the fixed heat treatment, carry out crystallization.The flow process of film formation process is with shown in Figure 2 the same.

In the present embodiment, with regard to the PZTN film of scope that the addition with Nb is made as 0 mole of %～30 mole %, use X-ray diffraction method to measure the lattice constant of crystallization shown in Figure 24 A and Figure 24 B.According to Figure 24 A and Figure 24 B, the addition of Nb is many more as can be known, and then lattice constant and the lattice constant in the c axle in a axle (or b axle) is approaching more.In addition, the index after the lattice constant (a, b, c) that has been volume change of the V (abc) among Figure 24 A.In addition, the V/V among Figure 24 A ₀Be the index V of the lattice constant of the V (abc) of PZTN crystallization and the PZT crystallization that volume change is not added Nb ₀The ratio.Like this, also can be according to V (abc) or V/V ₀The hurdle confirms that the PZTN crystallization is along with the addition of Nb increases, crystal lattice diminishes.

In addition, the lattice constant that basis shown in Figure 25 is so added the PZTN film that forms behind the Nb is calculated lattice with the lattice constant (a, b, c+3.96) of the Pt metal film rate that do not match, and the addition (mole %) of Nb is made as the figure that transverse axis is drawn.According to Figure 25, the effect that PZT class strong dielectric film is contained Nb not only improves the effect of strong dielectric characteristic in the various embodiments described above, also confirms the effect of this lattice constant near the lattice constant of platinum metals crystallizations such as Pt.Especially in the addition of Nb is zone more than 5 moles, confirm significantly to illustrate this effect.

Therefore, do not match, for example, when the addition of Nb is 30 moles of %, confirm that the lattice rate of not matching is improved to about 2% as if using method of the present invention, then alleviating as the metal film of electrode material and the lattice between the strong dielectric film.This is considered in the crystal structure of PZTN, generation has strong the combining of ions binding and total associativity simultaneously between the Nb atom of the Ti atom of displacement B side and the O atom, this adhesion is along the directive effect of compression crystal lattice, and lattice constant changes to the direction that diminishes.

In addition, platinum metals such as Pt are chemically stable materials, be applicable to the electrode material of strong dielectric memory or piezoelectric-actuator, method according to present embodiment, even if on this Pt metal film, directly form the PZTN film, also can relax the unmatched while of lattice than in the past, interfacial characteristics is improved.Therefore, the method for present embodiment can alleviate the fatigue properties of PZT class strong dielectric film, also is applicable in the element application of strong dielectric memory or piezoelectric-actuator etc.

(reference example)

In this example, make PbZr _0.4Ti _0.6O ₃Strong dielectric film.

In method in the past, use the solution that contains the Pb about 20% superfluously, this is to volatilize Pb and reduce crystallized temperature in order to suppress.But superfluous Pb how in the film of not knowing to obtain, former should the inhibition with minimal Pb excess quantity.

Therefore, using superfluous Pb is the PbZr of 0.5,10,15,20% 10 weight % concentration _0.4Ti _0.6O ₃Form with sol gel solution (solvent: the n-butanols), and then add the PbSiO of the 10 weight % concentration of 1 mole of % respectively ₃Form with sol gel solution (solvent: the n-butanols), carry out each operation of step ST20 shown in Figure 26～step ST25, form the PbZr of 200nm _0.4Ti _0.6O ₃Strong dielectric film.The surface texture of this moment is shown in Figure 27 A～Figure 27 C, and the XRD figure case is shown in Figure 28 A～Figure 28 C.

Needed Pb superfluous about 20% in the past, and crystallization was shown under the Pb of 5% surplus fully carries out.This expression is the PbSiO of 1 mole of % only ₃Catalyst, in order to reduce the crystallized temperature of PZT, superfluous Pb disappears basically.After, all use the 5%Pb excess solution as PZT, PbTiO ₃, and PbZrTiO ₃Formation solution.

Then, use at PbZrO by 10 weight % concentration of 4: 6 mixed ₃The n-butanols) and the PbTiO of 10 weight % concentration form with sol gel solution (solvent: ₃Form with sol gel solution (solvent: in the solution n-butanols), add the PbSiO of 1 mole of %10 weight % concentration ₃The formation sol gel solution (solvent: the mixed solution n-butanols), according to the flow process of Fig. 2, make 200nm～PbZr _0.4Ti _0.6O ₃Strong dielectric film.The hysteresis characteristic of this moment is shown in Figure 29 A and Figure 29 B, and square is good.But, leak simultaneously as can be known.

In addition,, in method in the past, use the flow process of described Figure 26, the PbZr that uses in 10 weight % concentration for relatively _0.4Ti _0.6O ₃Form with sol gel solution (solvent: the n-butanols), add the PbSiO of 1 mole of %10 weight % concentration ₃Form with sol gel solution (solvent: the mixed solution n-butanols), making 200nm-PbZr _0.4Ti _0.6O ₃Strong dielectric film.At this moment, hysteresis characteristic does not provide good magnetic hysteresis as shown in figure 30.

Therefore, after each strong dielectric film of use outgases analysis, shown in Figure 31 A and Figure 31 B.

Shown in Figure 31 A, the existing strong dielectric film that utilizes the PZT sol gel solution to make rises with respect to the temperature from room temperature to 1000 degree, confirms to be in relation to the degassing of H or C all the time.

On the other hand, shown in Figure 31 B, at the PbZrO that uses the mixed 10 weight % concentration of pressing 4: 6 ₃The n-butanols) and the PbTiO of 10 weight % concentration form with sol gel solution (solvent: ₃Form with sol gel solution (solvent: during the strong dielectric film of the present invention of the solution n-butanols), distinguished before decomposing and do not see the degassing basically.

This thinks by the PbZrO of use by 10 weight % concentration of 4: 6 mixed ₃The n-butanols) and the PbTiO of 10 weight % concentration form with sol gel solution (solvent: ₃Form with sol gel solution (solvent: the solution n-butanols), at first utilize the PbTiO of 10 weight % concentration in the mixed solution ₃The formation sol gel solution (solvent: the n-butanols), PbTiO ₃Crystallization on Pt, this becomes crystallization initial stage nuclear, and the lattice of eliminating Pt and PZT does not match the easy crystallization of PZT.And, think by using mixed solution, PbTiO ₃Form continuously on good interface with PZT, be associated with the square of good magnetic hysteresis.

2, the manufacture method of ferro-electric materials capacitor

Figure 32 A～Figure 32 C is the sectional view of manufacturing process's one example of the ferro-electric materials capacitor of pattern ground expression embodiment of the present invention.

(1) at first, shown in Figure 32 A, stack gradually on the fixed matrix 110 and form lower electrode 102, strong dielectric film 101, upper electrode 103.

As matrix 110, for example can adopt semiconductor substrate, resin substrate etc. to be applicable to the substrate of ferro-electric materials capacitor purposes arbitrarily, do not limit especially.

As lower electrode 102 and upper electrode 103, for example can adopt by noble metal monomers such as Pt, Ir, Ru or the electrode that constitutes based on the composite material of described noble metal.In addition, lower electrode 102 and upper electrode 103 for example can use known film build methods such as sputtering method or sedimentation to form.In addition, when the formation element of strong dielectric during to lower electrode 102 and upper electrode 103 diffusions, interface portion at electrode and strong dielectric film 101 produces the composition fluctuation, the square reduction of magnetic hysteresis is so expectation lower electrode 102 and upper electrode 103 have the indiffusible compactness of formation element of strong dielectric.Therefore, in order to improve the compactness of lower electrode 102 and upper electrode 103, can adopt by the method for the heavy gas spatter film forming of quality or make the oxide of Y, La etc. disperse method etc. in the noble metal electrode.

Strong dielectric film 101 is to contain Pb, Zr, Ti and Nb as the so-called PZTN composite oxides that constitute element.In addition, strong dielectric film 101 can form by for example using sol gel solution that spin-coating method etc. will contain Pb, Zr, Ti, Nb to be coated on the lower electrode 102.As this sol gel solution, can use the solution that mixes the 1st sol gel solution, the 2nd sol gel solution and the 3rd sol gel solution, wherein, the 1st sol gel solution is in order to form the PbZrO based on Pb and Zr ₃The perovskite crystallization and under anhydrous state in n-butanols equal solvent the dissolving condensation polymer solution, the 2nd sol gel solution is in order to form the PbTiO based on Pb and Ti in the formation metallic element of PZTN strong dielectric phase ₃The perovskite crystallization and under anhydrous state in n-butanols equal solvent the dissolving condensation polymer solution, the 3rd sol gel solution is in order to form the PbNbO based on Pb and Nb in the formation metallic element of PZTN strong dielectric phase ₃The perovskite crystallization and under anhydrous state in n-butanols equal solvent the dissolving condensation polymer solution.And, when forming strong dielectric film 101,, also can add the sol gel solution that contains silicate or germanate in order to reduce the crystallized temperature of PZTN composite oxides.Particularly, can be for example above, the 5 moles of % of less than of 1 mole of % in above-mentioned mixed sols gel solution, further add the 4th sol gel solution, the 4th sol gel solution for example is in order to form PbSiO ₃Crystallization and under anhydrous state in n-butanols equal solvent the dissolving condensation polymer solution.By mixing this 4th sol gel solution, but can be by constituting crystallization under the temperature range that the crystallized temperature that contains the PZTN composite oxides that Nb, crystallized temperature uprise in the element is the elementization below 700 degree.

In addition, preferably carry out interim heat treatment under the temperature of 101 pairs of this coated film of strong dielectric film non-crystallizableization of PZTN composite oxides in oxidizing atmosphere (for example below 400 degree), the PZTN composite oxides are become noncrystalline state.Thereby strong dielectric film 101 can advance operation described later owing to the crystalline attitude of right and wrong becomes the state that does not have a boundary when preventing to constitute Elements Diffusion.In addition, in oxidizing atmosphere, carry out this interim heat treatment, also can play to form back importing in strong dielectric film 101 and make the required oxygen composition of PZTN composite oxides crystallization at diaphragm described later.

(2) then, shown in Figure 32 B, etching lower electrode 102, strong dielectric film 101 and upper electrode 103 are processed into the shape of expectation, form by SiO ₂The diaphragm 104 that (silica) film constitutes is to cover described lower electrode, strong dielectric film and upper electrode.The diaphragm 104 of this moment can use three monosilanes (TMS) to utilize the CVD method to form.Three monosilanes (TMS) are compared with the general tetraethyl orthosilicate of using (TEOS) during silicon oxide film forms, and the generation hydrogen amount in the CVD technology is few.Therefore, if use three monosilanes (TMS), then can reduce the technology infringement that the reduction reaction to strong dielectric film 101 causes.In addition; because using the formation technology of the diaphragm 104 of three monosilanes (TMS) compares with the formation technology of using TEOS (formation temperature is more than 400 degree) and can carry out under low temperature (room temperature～350 degree); so in (1) operation; strong dielectric film 101 is being formed under the situation of noncrystalline state; can prevent that it is constant to keep noncrystalline state owing to the PZTN composite oxides crystallizations such as heat that produce in the formation operation of this diaphragm 104.

(3) then, shown in Figure 32 C, carry out the heat treatment that crystallization constitutes the PZTN composite oxides of strong dielectric film 101, can obtain having the ferro-electric materials capacitor of PZTN strong dielectric crystalline film 101a.In this heat treatment, not only under oxygen atmosphere, even if pass through at for example Ar or N ₂Deng under the non-oxidized gas atmosphere or the heat treatment in the atmosphere, also crystallizableization PZTN composite oxides.

Here, the manufacture method that just is suitable for present embodiment is come on the ferro-electric materials capacitor that is made of PZTN strong dielectric film, Pt upper electrode, is formed the SiO of use TMS ₂Diaphragm is determined at this SiO ₂Diaphragm forms the back and heat-treat the results are shown among Figure 33 A and Figure 33 B of electric capacity hysteresis characteristic under the situation of post crystallization PZTN strong dielectric in oxygen atmosphere and in the atmosphere.Figure 33 A is illustrated in the situation of heat-treating in the oxygen atmosphere, and Figure 33 B is illustrated in the situation of heat-treating in the atmosphere.According to Figure 33 A and Figure 33 B, in oxygen atmosphere and under the situation of heat-treating under arbitrary atmosphere in the atmosphere,, all can obtain the good hysteresis characteristic of square although do not form the barrier film that anti-hydrogen is used.This is because implement interim heat treatment under oxidizing atmosphere when strong dielectric film 101 forms, so import the required oxygen of crystallization in advance in film.That is, in the manufacture method of present embodiment, can not rely on the crystallization that heat treated atmosphere is carried out strong dielectric.And, carrying out under the non-oxidized gas atmosphere under the heat treated situation that crystallization uses, in the situation of the manufacture method that is applicable to strong dielectric memory described later etc., can prevent the oxidative damage that causes high-temperature heat treatment to cause to the peripheral components (for example metal wiring) beyond the electric capacity.In addition; the crystallization of the PZTN composite oxides in this operation, carries out upper electrode 103 with the outside contact hole that is connected the metal wiring of usefulness so also can be formed for forming in diaphragm 104 because the dependence of the gaseous species in the atmosphere is few with heat treatment afterwards again.

In addition, just on the ferro-electric materials capacitor that the Pt lower electrode, PZTN strong dielectric film, the Pt upper electrode that are suitable for by the manufacture method of present embodiment constitute, forms the SiO of use TMS ₂Diaphragm and at this SiO ₂Diaphragm forms post crystallization PZTN strong dielectric, measures SiO ₂The formation temperature of diaphragm is made as room temperature, the hysteresis characteristic when 125 degree, 200 are spent and does not form SiO as a comparative example ₂Hysteresis characteristic when diaphragm and crystallization PZTN strong dielectric film, and the results are shown among Figure 34 of variation of measuring the value of its remnant polarization amount 2Pr.According to Figure 34, even if under room temperature, 125 degree, the arbitrary temperature of 200 degree, form SiO ₂Diaphragm is not all seen variation among the remnant polarization amount 2Pr, confirms to obtain no less than forming SiO ₂Value during diaphragm.Promptly; in the manufacture method of present embodiment; even if suppose the infringement that strong dielectric film 101 is subjected to producing in the technology when forming diaphragm 104 hydrogen causes; also can by after carry out the crystallization heat treatment of PZTN composite oxides; when recovering this infringement; crystallization PZTN composite oxides so can omit the formation technology that essential in the past protection strong dielectric film 101 is not subjected to the barrier film that reduction reaction influences, can be realized the reduction of productive raising and production cost.

3, strong dielectric memory

Figure 35 A and Figure 35 B are the pie graphs of the ferroelectric memory device 300 of the simple matrix type in the expression embodiments of the present invention.Figure 35 A is a plane graph, and Figure 35 B is the sectional view along the A-A line of Figure 35 A.Ferroelectric memory device 300 has the word line 301～303 of the arrangement institute determined number that is formed on the substrate 308 and arranges the bit line 304～306 of institute's determined number shown in Figure 35 A and Figure 35 B.Between word line 301～303 and bit line 304～306, insert the strong dielectric film 307 that constitutes by the PZTN that illustrates in the above-mentioned execution mode, in the intersection region of word line 301～303 and bit line 304～306, form ferro-electric materials capacitor.

In the ferroelectric memory device 300 of arranging the memory cell that constitutes by this simple matrix, utilize the drive circuit of not shown periphery or read with (being referred to as peripheral circuit) such as amplifying circuits and carry out writing and reading the ferro-electric materials capacitor in the intersection region that is formed at word line 301～303 and bit line 304～306.This peripheral circuit is formed on memory cell array other substrate in addition by MOS, be connected on word line 301～303 and the bit line 304～306, perhaps also can peripheral circuit be integrated on the substrate identical with memory cell array by in substrate 308, using monocrystalline silicon substrate.

Figure 36 is an expression sectional view in the present embodiment, that memory cell array and peripheral circuit be integrated in jointly an example of the ferroelectric memory device 300 on the same substrate.

Among Figure 36, form MOS transistor 402 on monocrystalline silicon substrate 401, this transistor formation region territory constitutes peripheral circuit portion.MOS transistor 402 is made of monocrystalline silicon substrate 401, source drain zone 405, gate insulating film 403 and gate electrode 404.

In addition, ferroelectric memory device 300 has element separation oxide-film the 406, the 1st interlayer insulating film the 407, the 1st wiring layer 408 and the 2nd interlayer insulating film 409.

In addition, ferroelectric memory device 300, has the memory cell array that constitutes by ferro-electric materials capacitor 420, strong dielectric memory 420, by the lower electrode that constitutes word line or bit line (the 1st electrode or the 2nd electrode) 410, contain strong dielectric and normal dielectric mutually strong dielectric film 411 and be formed on the strong dielectric film 411 and the upper electrode (the 2nd electrode or the 1st electrode) 412 that constitutes bit line or word line constitutes.

And ferroelectric memory device 300 has the 3rd interlayer insulating film 413 on ferro-electric materials capacitor 420, utilizes the 2nd wiring layer 414 to come connected storage cell array and peripheral circuit.With regard to ferroelectric memory device 300, on the 3rd interlayer insulating film 413 and the 2nd wiring layer 414, form diaphragm 415.

According to ferroelectric memory device 300 with above formation, can be on same substrate integrated memory cell array and peripheral circuit portion.In addition, ferroelectric memory device 300 shown in Figure 36 is the formations that form memory cell array on peripheral circuit portion, but also can constitute not configuration memory units array on peripheral circuit portion, memory cell array contacts with the peripheral circuit portion plane earth.

The ferro-electric materials capacitor 420 that uses in the present embodiment owing to be made of the PZTN of above-mentioned execution mode, so the square property of magnetic hysteresis is very good, has stable disturbance characteristic.And this ferro-electric materials capacitor 420 is because the low temperatureization of processing temperature is few to the infringement of other elements such as peripheral circuit, and in addition, processing infringement (the especially reduction of hydrogen) is few, worsens so can suppress to damage the magnetic hysteresis that causes.Therefore, by using this ferro-electric materials capacitor 420, but practicability simple matrix type ferroelectric memory device 300.

In addition, the structure chart of expression 1T1C type ferroelectric memory device 500 among Figure 37 A is as variation.Figure 37 B is the equivalent circuit diagram of ferroelectric memory device 500.

Shown in Figure 37 A, ferroelectric memory device 500 is by lower electrode 501, is connected in the electric capacity 504 (1C) that the strong dielectric film 503 of the PZTN strong dielectric of upper electrode 502 on the plateline and suitable present embodiment constitutes, the switch that is connected on the data wire 505 with one of source/drain electrodes side and has a gate electrode 506 that is connected on the word line constitutes with transistor unit 507 (1T), is similar to the memory component of the structure of DRAM.Writing and reading of the memory of 1T1C type can be carried out at a high speed below 100ns, and, because the data that write are difficult for mistake, so the displacement of expectation SRAM etc.

4, the manufacture method of strong dielectric memory

Below, illustrate that the manufacture method that illustrates in will the manufacture method of ferro-electric materials capacitor " 2, " hurdle is applicable to the situation in the manufacture method of strong dielectric memory.

Figure 38 A～Figure 38 C is the sectional view of manufacturing process's one example of the strong dielectric memory of pattern ground expression embodiment of the present invention.

In the present embodiment, at first shown in Figure 38 A, on matrix 110, form lower electrode 102, PZTN strong dielectric film 101, the upper electrode 103 of ferro-electric materials capacitor 100 successively.At this moment, PZTN strong dielectric film 101 is implemented to become noncrystalline state after the interim heat treatment in oxidizing atmosphere.In addition, as matrix 100, for example shown in Figure 38 A, can use and on semiconductor substrate 111, form the matrix that the transistor 116 of usefulness is selected in the unit.This transistor 116 can have source/drain 113, grid oxidation film 114, gate electrode 115.In addition, on the source/drain 113 of one of transistor 116 side, for example form the plug electrode 117 that constitutes by tungsten etc., can adopt the stacked structure that can form with the lower electrode 102 of ferro-electric materials capacitor 100 with being connected.In addition, in matrix 110, transistor 116 utilizes element separated region 112 that each unit is separated between the unit, on the top of transistor 116, for example can have the interlayer insulating film 118 that is made of oxide-film etc.

Then, in the manufacturing process of present embodiment, shown in Figure 38 B, ferro-electric materials capacitor 110 is patterned to the size and the shape of expectation.Afterwards, use three monosilanes (TMS) to form by SiO ₂Diaphragm 104 with covering ferro-electric materials capacitor 100, and forms after the contact hole 105 of outside connection usefulness therein, heat-treats, and crystallization PZTN strong dielectric forms PZTN strong dielectric film 101a.When the crystallization of PZTN strong dielectric, can in nonoxidizing atmosphere, carry out the heat treatment that crystallization is used.In view of the above, can prevent the oxidative damage that causes high-temperature heat treatment to cause to peripheral components outside the ferro-electric materials capacitor 100 (for example metal wiring) etc.

Finally, shown in Figure 38 C, at SiO ₂Form the contact hole that transistor 116 is connected usefulness with food and beverage department in the diaphragm 104, and obtain strong dielectric memory by forming metallic wiring layer 191,192.According to the manufacturing process of present embodiment, can omit the formation technology that essential in the past protection strong dielectric film 101 is not subjected to the barrier film of reduction reaction infringement usefulness, can realize the reduction of productive raising and production cost.In addition, even if also can form ferro-electric materials capacitor 100, so the strong dielectric memory of the characteristic that can obtain with the good hysteresis characteristic of square owing to omit the formation technology of this barrier film.

In addition, the above-mentioned manufacturing process that so-called 1T1C type strong dielectric memory has been described, but the manufacture method of the ferro-electric materials capacitor of present embodiment is used in the manufacturing process of strong dielectric memory of various unit mode applicable to so-called 2T2C type or simple matrix type (crosspoint type) etc. in addition.

5, piezoelectric element and ink jet recording head

Below, describe the ink jet recording head in the embodiment of the present invention in detail.

In following ink jet recording head, promptly constitute the part of the pressure generating chamber that is communicated with the nozzle opening of ejection ink droplet by oscillating plate, make this oscillating plate distortion by piezoelectric element, ink to pressure generating chamber is exerted pressure, from nozzle opening ejection ink droplet, practicability use along the ink jet recording head of the piezoelectric-actuator of the longitudinal vibration mode of the axial stretching of piezoelectric element, with two kinds of the ink jet recording heads of the piezoelectric-actuator that uses beam mode etc.

In addition, ink jet recording head as the executive component that uses beam mode, for example knownly in the surperficial integral body of oscillating plate, form uniform piezoelectric body layer by film technique, and utilize photoetching process that this piezoelectric body layer is divided into shape corresponding to pressure generating chamber, each pressure generating chamber is formed piezoelectric element independently.

Figure 39 is the signal exploded perspective view of the ink jet recording head of expression one embodiment of the present invention, and Figure 40 A, 40B are plane graph and the A-A ' sectional views of Figure 39, and Figure 41 is the schematic diagram of the layer structure of expression piezoelectric element 700.As shown in the figure, stream forms substrate 10 and is made of face orientation (110) monocrystalline silicon substrate in the present embodiment, forms the thickness that forms by thermal oxidation in advance, be made of silicon dioxide and be 1～2 micron elastic membrane 50 in the face of one side.In stream forms substrate 10, be set side by side with a plurality of pressure generating chamber 12 along its Width.In addition, form in the length zone laterally of pressure generating chamber 12 of substrate 10 at stream, form interconnecting part 13, interconnecting part 13 provides path 14 being communicated with each pressure generating chamber 12 through the ink to each pressure generating chamber 12 setting.In addition, interconnecting part 13 is communicated with the deposit portion 32 of hermetic sealing substrate 30 described later, constitutes the part of the deposit device 800 of the common ink chamber that forms each pressure generating chamber 12.Ink provides path 14 to form with specific pressure generating chamber 12 narrow width, will keep constant from the stream impedance of the ink the interconnecting part 13 feed pressure generating chamber 12.

In addition, form the opening surface side of substrate 10, fixing near the nozzle plate 20 of the nozzle opening 21 on running through the end that the ink that is communicated in each pressure generating chamber 12 is set provides path 14 opposition sides through bonding agent or heat fusing film etc. at stream.

On the other hand, form the opposition side of the opening surface of substrate 10, as mentioned above, form thickness and be about 1.0 microns elastic membrane 50, on this elastic membrane 50, be formed with the insulator film 55 that thickness is about 0.4 micron at this stream.And on this insulator film 55, lower electrode film 60, the thickness that utilizes the stacked formation thickness of technology described later to be about 0.2 micron is about the upper electrode film 80 that 1.0 microns piezoelectric body layer 70 and thickness are about 0.05 micron, to have constituted piezoelectric element 700.Here, piezoelectric element 700 is meant the part that contains lower electrode film 60, piezoelectric body layer 70 and upper electrode film 80.Usually, arbitrary electrode of piezoelectric element 700 as common electrode, is constituted each 12 patterning the opposing party's of pressure generating chamber electrode and piezoelectric body layer 70.And, will constitute by the either party's electrode and the piezoelectric body layer 70 of patterning, be called the active portion of piezoelectrics at this by part to two electrode application voltage, generation piezoelectric deforming.In the present embodiment, lower electrode film 60 is made as the common electrode of piezoelectric element 700, upper electrode film 80 is made as the single electrode of piezoelectric element 700, but the cooperation by drive circuit or distribution, even if will top of may as well do.In either case, can form the active portion of piezoelectrics to each piezoelectricity generating chamber.Here, piezoelectric element 700 and the oscillating plate that the driving that utilizes this piezoelectric element 700 produces displacement are collectively referred to as piezoelectric-actuator.In addition, piezoelectric body layer 70 independently is provided with each pressure generating chamber 12, as shown in figure 40, and by the strong dielectric film 71 (71a～71f) constitute of multilayer.

Ink jet recording head constitutes the part of the head unit possess the ink flow path that is communicated with ink chuck etc., is loaded on the inkjet recording device.Figure 42 is the schematic diagram of an example of this inkjet recording device of expression.As shown in figure 42, head unit 1A and 1B with ink jet recording head are provided with chuck 2A and the 2B that the formation ink provides the unit removably, and the carriage 3 that loads this head unit 1A and 1B is arranged on the bracket axle 5 that is installed on the apparatus main body 4 with axially moving freely.This head unit 1A and 1B for example spray black ink composition and color inks composition respectively.In addition, pass to carriage 3 through not shown a plurality of gears and synchronous belt 7, the carriage 3 that loads head unit 1A and 1B is moved along bracket axle 5 by actuating force with drive motors 6.On the other hand, at apparatus main body 4 upper edge bracket axles 5 pressing plate 8 is set, transmission is by the record sheet S as recording medium such as the paper of paper supplies such as not shown paper feed roller on pressing plate 8.

In addition, the ink jet recording head of ejection ink is illustrated as jet head liquid as an example, but the present invention can use also the jet head liquid of piezoelectric element and liquid injection apparatus integral body as object.As jet head liquid, for example be useful on recording head in the image recording structure such as printer, be used for the manufacturing of filter such as LCD look material injector head, be used for electrode material injector head that OLED display, FED electrodes such as (face active displays) form, be used for the biological organic substance that biochip makes and spray first-class.

The piezoelectric element of present embodiment is owing to the PZTN film with above-mentioned execution mode is used for piezoelectric body layer, so obtain following effect.

(1) owing to the total associativity that improves in the piezoelectric body layer, institute is so that the piezoelectric constant raising.

(2),, the efficient as piezoelectric element is improved so the generation of the out-phase in the interface of inhibition piezoelectric body layer and electrode applies electric field easily because the PbO that can suppress in the piezoelectric body layer is damaged.

(3) owing to the leakage current that suppresses piezoelectric body layer, so but filming piezoelectric body layer.

In addition, the jet head liquid of present embodiment and liquid injection apparatus are because use contains the piezoelectric element of above-mentioned piezoelectric body layer, so especially obtain following effect.

(4) owing to can alleviate the fatigue deterioration of piezoelectric body layer,, reliability is improved so can suppress the variation in time of the displacement of piezoelectric body layer.

Preferred forms of the present invention more than is described, but the invention is not restricted to this, can in the scope of invention spirit, utilize various execution modes to implement.

For example, on strong dielectric film 101,, also can have equal effect even if Ta, W, V, Mo are applied PZT to replace Nb as substance.In addition, even if Mn is used as substance, also can have the effect the same with Nb.In addition,, overflow, also consider usually to replace Pb,, lanthanide series such as La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu are for example arranged as substitute with the above unit of+3 valencys in order to prevent Pb by same consideration.In addition, the additive as promoting crystallization also can use germanate (Ge) without silicate (Si).Hysteresis characteristic when expression uses the Ta of 10 moles of % to replace Nb as substance to PZT among Figure 43 A.Hysteresis characteristic when expression uses the W of 10 moles of % to replace Nb as substance to PZT among Figure 43 B.Under the situation of using Ta, also can obtain the effect the same as can be known with adding Nb.In addition, under the situation of using W, with regard to the hysteresis characteristic that obtains good insulating, have and the same effect of interpolation Nb as can be known.

Claims (17)

1. strong dielectric film is by AB _1-XNb _XO ₃General formula represent, wherein,

At least contain Pb as the A element,

Constitute by more than at least a among Zr, Ti, V, W, Hf and the Ta as the B element,

0.1≤x≤0.4。

2. strong dielectric film according to claim 1, wherein,

0.1≤x≤0.3。

3. strong dielectric film according to claim 1, wherein,

0.1≤x≤0.2。

4. strong dielectric film according to claim 1, wherein,

0.2≤x≤0.3。

5. strong dielectric film according to claim 1, wherein,

0.2≤x≤0.4。

6. strong dielectric film according to claim 1, wherein,

0.3≤x≤0.4。

7. according to each the described strong dielectric film in the claim 1～6, wherein,

Described strong dielectric film be Ti ratio of components Zr form many and Ti formed in 2.5 moles of 40 moles of PZT class strong dielectric films that are replaced as Nb below the % more than the %, comprise the Si more than 0.5 mole of %.

8. strong dielectric film according to claim 7, wherein,

Described Si is more than 0.5 mole of %, less than 5 moles of %.

9. according to each the described strong dielectric film in the claim 1～6, wherein,

Described strong dielectric film be Ti ratio of components Zr form many and Ti formed in 2.5 moles of 40 moles of PZT class strong dielectric films that are replaced as Nb below the % more than the %, comprise Si and Ge more than 0.5 mole of %.

10. the manufacture method of strong dielectric film according to claim 9, wherein,

Described Si and Ge are more than 0.5 mole of %, less than 5 moles of %.

11. according to each the described strong dielectric film in the claim 1～6, wherein,

Described strong dielectric film is that Ti ratio of components Zr forms many and with 2.5 moles of 40 moles of PZT class strong dielectric films that are replaced as Nb below the % more than the % in the Ti composition, has at least a crystal structure of tetragonal system and rhombohedral system.

12. a ferroelectric memory device uses each described strong dielectric film in the claim 1～11.

13. a semiconductor element uses each described strong dielectric film in the claim 1～11.

14. a piezoelectric element uses each described strong dielectric film in the claim 1～11.

15. a piezoelectric-actuator uses the described piezoelectric element of claim 14.

16. a jet head liquid uses the described piezoelectric-actuator of claim 15.

17. a printer uses the described jet head liquid of claim 16.

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