JPH0517177A - Amorphous ferroelectric oxide material and production thereof - Google Patents

Abstract

PURPOSE:To provide the title ferroelectric material applicable to thin film-type capacitor elements, ferroelectric memories and electrooptical devices, etc. CONSTITUTION:The objective ferroelectric material consisting of an amorphous ternary oxide predominant in a transition metal oxide(M2O3)-silicon oxide(SiO2)- LiNb03 type compound(ABO3). (where, M2O3 is at least one compound selected from respective oxides of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Pd, Hf, Ta, W, In, and lanthanoids; ABO3 is a ferroelectric, antiferroelectric or dielectric LiNbO3-type compound).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous ferroelectric oxide material capable of forming a thin film capacitor element, a ferroelectric memory, an electro-optical device and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in an inorganic ferroelectric material represented by a perovskite dielectric material,
The ferroelectric property is expressed based on a certain rule in crystal symmetry. Similarly, in the LiNbO ₃ dielectric material, which is also known to exhibit ferroelectricity, the cause of the ferroelectricity is due to a certain rule in crystal symmetry. For this reason, it is important to enhance the crystallinity of the material in order to make the ferroelectricity remarkable. In fact, LiN
In the material having the bO ₃ crystal structure, many efforts have been made in relation to the above-mentioned matters such as adjusting the firing temperature or improving the sintering density in order to enhance the crystallinity. On the other hand, in the case of capacitors, ferroelectric memories, etc. to which such ferroelectrics are applied, when the material is polycrystalline, the existence of grain boundaries causes a decrease in withstand voltage, and leakage current occurs along the grain boundaries. However, there is a problem that it causes a loss in the condenser and impairs the retention of information in the memory. In addition, it is difficult to miniaturize various devices due to the existence of crystal grain boundaries, which is a big problem in today's miniaturization of various devices applying dielectric characteristics. Also, when developing a dielectric material as an electro-optical element, the presence of crystal grain boundaries causes light scattering, which reduces the optical signal intensity in order to make the optical device function,
There are serious problems such as increased noise. To solve these problems, there is an attempt to configure a ferroelectric material in a thin film to form a microdevice-shaped capacitor, a ferroelectric memory, or an electro-optical device. In order to avoid the generation of crystal grain boundaries, attempts have been made to produce single crystal dielectric thin films and amorphous dielectric thin films. In the single crystal dielectric thin film, a single crystal substrate of sapphire, MgO, GGG, or the like is used as a substrate in consideration of matching of lattice constants with the thin film in order to promote epitaxial growth. Further, a method such as a sputtering method or a liquid phase epitaxial growth method (LPE method) is used for forming the film.
However, in any of the methods, an expensive single crystal substrate is used as a substrate, various conditions must be controlled strictly for epitaxial growth, and the crystal axis of crystal growth is restricted to the orientation of the single crystal. Further, if the difference between the lattice constant of the single crystal substrate and the lattice constant of the thin film becomes too large, it becomes difficult to grow the single crystal thin film, and thus actual thin film production is not easy. Furthermore, in the epitaxial growth method as described above, for thin film single crystallization,
Since a high heat treatment temperature of approximately 600 ° C. or higher is required, there is also a problem that the heat treatment of the film impairs the surface property of the film, which has been a major barrier in making a ferroelectric material into a microdevice.

Amorphous thin films, like single crystal thin films,
Since there is no crystal grain boundary, it is expected to be put to practical use in order to solve various problems occurring in the above-mentioned ferroelectric polycrystalline material. However, there is no conventional example in which an amorphous ferroelectric thin film is produced using a LiNbO ₃ type dielectric.

[0004]

The object of the present invention is that the material according to the present invention has an amorphous structure, and for this reason there is no grain boundary or pores found in a sintered body, a capacitor with small loss and a ferroelectric memory with high information retention. , Or a material applicable to an electro-optical device or the like.

[0005]

SUMMARY OF THE INVENTION The present invention is a transition metal oxide (M ₂ O ₃ ) -silicon oxide (SiO ₂ ) -LiN.
A ternary oxide containing a bO ₃ type compound (ABO ₃ ) as a main component is formed on a substrate by using an amorphous film forming means such as a vacuum deposition method or a sputtering method, while keeping the substrate temperature at 300 ° C. or lower. The above problem is solved by adopting a method in which a ferroelectric thin film is produced as it is without being subjected to heat treatment or the like, which is produced as a crystalline thin film. That is, the present invention provides a transition metal oxide (M ₂ O ₃ ) -silicon oxide (SiO ₂ ) -LiNb.
An amorphous ferroelectric material comprising a ternary oxide containing an O ₃ type compound (ABO ₃ ) as a main component, and the ternary oxide having an amorphous structure (however,
M ₂ O ₃ is Sc, Ti, V, Cr, Mn, Fe, Co,
Ni, Y, Zr, Nb, Mo, Pd, Hf, Ta, W,
It is at least one selected from the group consisting of oxides of In and lanthanum series elements, and is a LiNbO ₃ type compound exhibiting ABO ₃ ferroelectricity. ) Is provided. Further, according to the present invention, the above ternary oxide is formed as an amorphous thin film on a substrate by using a film forming means while keeping the substrate temperature at 300 ° C. or lower, and the ferroelectric film is produced as it is. The present invention provides a method for producing an amorphous ferroelectric oxide material, which is characterized by obtaining an oxide material.

The amorphous ferroelectric oxide material of the present invention is a transition metal oxide (M ₂ O ₃ ) -silicon oxide (Si
O ₂ ) -LiNbO ₃ type compound (ABO ₃ ) as a main component. Here, M ₂ O ₃ is Sc, T
i, V, Cr, Mn, Fe, Co, Ni, Y, Zr, N
b, Mo, Pd, Hf, Ta, W, In, and La, C
e, Pr, Nd, Sm, Eu, Gd, Tb, Dy, H
at least one selected from the group consisting of oxides of lanthanum series elements of o, Er, Tm, Yb and Lu, and A
BO ₃ is a LiNbO ₃ type compound exhibiting ferroelectricity.
The amorphous ferroelectric oxide material of the present invention is formed by forming the ternary oxide in the form of an amorphous structure. FIG. 1 shows a composition showing ferroelectricity while the thin film has an amorphous structure. The composition range is α, β,
It is a region surrounded by γ, δ, ε, and φ. Here,
The straight line αβ is a straight line represented by aM ₂ O ₃ − (1-a) SiO ₂ , and the straight line βγ is 0.90SiO ₂ −0.10.
A straight line represented by (bM ₂ O _3- (1-b) ABO ₃ ), a straight line γδ is a straight line represented by cSiO _2- (1-c) ABO ₃ , and a straight line δε is 0.20 ( dSiO ₂ −
A straight line represented by (1-d) M ₂ O ₃ ) −0.80ABO ₃ , and the straight line εφ is eABO ₃ − (1-e) M ₂ O ₃
The straight line φα is 0.90 M ₂ O ₃ −
0.10 (fABO _3- (1-f) SiO ₂ ), which is a straight line, and 0.10 ≦ a ≦ in each composition line.
0.90 and 0.00 ≦ b ≦ 1.00 and 0.20 ≦ c
≤ 0.90 and 0.00 ≤ d ≤ 1.00 and 0.20 ≤
The composition line is defined in the range of e ≦ 0.90 and 0.00 ≦ f ≦ 1.00. In the figure, ABO ₃ is Li
Various NbO ₃ type dielectric materials (LiTaO ₃ , LiNbO
₃ etc. ferroelectric material). In Fig. 1 and in the triangular composition diagram below, the division of three sides is 0.1 (mol)
Ratio). As can be seen from this figure, an amorphous film cannot be formed in a region where the concentration of the LiNbO ₃ type dielectric material is high. However, M ₂ O ₃ or S
The excessive addition of iO ₂ makes the material amorphous and exhibits ferroelectricity.

According to the method for producing an amorphous ferroelectric thin film of the present invention, the above ternary oxide is formed as an amorphous thin film on a substrate using a film forming means while maintaining the substrate temperature at 300 ° C. or lower. By manufacturing, a ferroelectric oxide material can be obtained as it is. As the film forming means, a generally used thin film forming process such as a vacuum vapor deposition method and a sputtering method is used. During film formation, the substrate temperature was set to the crystallization temperature (500 to 6) of the amorphous composite oxide.
By forming a film in an oxygen atmosphere at a substrate temperature of 00 ° C.) or lower, preferably 300 ° C. or lower, an amorphous oxide thin film having ferroelectricity can be obtained. According to the present invention, a thin film exhibiting ferroelectric properties can be easily obtained without performing heat treatment for crystallizing a thin film after epitaxial growth or film formation using a single crystal substrate or the like at the time of film formation. For this reason, it is possible to significantly reduce the time and effort required to produce a ferroelectric thin film, and to produce a film with very good surface properties and without grain boundaries. It is expected to be applied to micro devices such as capacitors and electro-optical devices.

[0008]

【Example】

Example 1 An RF magnetron sputtering apparatus was used to prepare a thin film, and a stainless petri dish having a diameter of 76 mm and a depth of 4 mm was placed on a cathode plate, and SiO ₂ and Fe ₂ O were placed therein.
_3, it was used filled with mixed powder of LiTaO ₃ as a target. SiO ₂ , Fe ₂ O ₃ , LiTaO ₃
Prior to filling each of the powders in a stainless petri dish, a mixture of powders of each oxide material was subjected to wet mixing with ethanol as a solvent for 30 minutes using a paint shaker. Thereafter, the solvent was removed and dried, and then the stainless dish was filled and used as a sputtering target. The sputtering gas is a mixed gas of Ar: O ₂ = 7: 3, and the purity of each gas of Ar and O ₂ is 99.9.
95% or more was used. A (111) oriented Si wafer was used as the substrate. The Si wafer was an n-type and had a resistivity of about 1 (Ωcm). Si
An SiO ₂ layer having a film thickness of 200 nm is previously provided on the wafer by oxidation. The purpose of providing this layer is mainly to secure electrical insulation at the time of evaluation of dielectric properties. Prior to film formation, raise the substrate temperature to 200 ℃,
The desorption treatment of the water adsorbed on the substrate surface was mainly performed. Furthermore, pre-sputtering was performed for about 30 minutes before film formation to clean the target surface and stabilize the film quality and thin film composition during sputtering film formation.
The degree of vacuum is 2 × 10 ^-7 Tor before introducing the sputtering gas.
It was confirmed that the value was below r. During the sputtering film formation, the total gas pressure was kept constant at 25 mTorr. During sputtering, the copper anode fixing the substrate was water-cooled and the substrate temperature during film formation was maintained at 20 to 25 ° C. The high frequency input power was 110 W, and the sputtering film formation was performed for 30 to 60 minutes. The thin films obtained in this manner showed a change in film thickness due to a change in the sputtering rate depending on the composition of the target, but each thin film showed a film thickness of 500 to 1000 nm.

By the thin film forming process as described above, S
A sputtered thin film containing ternary elements of iO ₂ , Fe ₂ O ₃ , and LiTaO ₃ was prepared. No. 2 in FIG. The compositions shown by the numbers 1 to 25 were prepared, and the film structure was evaluated and the dielectric properties were measured for each composition. When the correspondence between the target composition and the thin film composition of the obtained thin film was examined by the inductive plasma emission analysis method, it was found that the two compositions corresponded with an error of about 3%. Therefore, in the following description, the composition of the target is used as the composition of the thin film. The dielectric properties were evaluated by a soya tower circuit commonly used in the characterization. Using this circuit, the electric field dependence of the electric flux density (D) was evaluated and the value of spontaneous polarization (Ps) was obtained. In the evaluation of the dielectric property, the electrode configuration as shown in FIG. 3 was used, and the electrode 4 for applying an electric field to the thin film 1 was taken out from the oxide thin film 2 side so that two capacitors C ₁ could be equivalently formed. , C ₂ are connected in series to prevent the Schottky characteristic generated at the interface between the metal electrode and Si when the metal electrode is taken out from the Si 3 side, and an accurate dielectric evaluation is performed. As the metal electrode, an Au electrode having a thickness of about 100 nm and a diameter of 4 mm was formed on the surface of the thin film by a sputtering method.

As-deposited state (As-de) of the sputtering thin film produced by the above-mentioned thin film forming method.
The structure and dielectric properties of the (position state) were evaluated.
First, the results of evaluating the structure of the thin film will be described. FIG. 4 shows the XRD diffraction results of the films formed on the dotted line A in FIG. 2 after the sputter deposition of various compositions. No. shown in FIG. 10, No. 15, No. 18 is shown in FIG.
It corresponds to the number inside and represents the composition of the thin film sample. XR
A Cu target was used as the radiation source of D, and a monochromator was attached. In the XRD result shown in FIG. 4, the diffraction line corresponding to the (111) plane of Si used as the substrate is also seen to be superimposed on the diffraction result of the thin film. LiTaO
₃ Thin film No. In No. 7, the thin film was crystallized in the As-deposit state, but SiO ₂ and Fe ₂ O ₃
Is excessive (No. 10, No. 15, No. 1)
In 8), no X-ray diffraction line due to crystallization of the thin film was observed, which shows that the thin film is in an amorphous state. Further, FIG. 5 shows the XRD diffraction result of the film after the sputter film formation of various compositions produced on the dotted line B of FIG. No. shown in FIG. 3, No. 16, No. 22 corresponds to the number in FIG. 2 and represents the composition of the thin film sample. As is clear from FIG. 5, XRD results show that Si (111)
There is no clear diffraction line other than the diffraction line corresponding to the surface, and it can be seen that the thin films having these compositions all have an amorphous structure. Further, No. 2 shown in FIG. 1-No. Two
As a result of performing XRD analysis on all the films of No. 5 in the thin film indicated by black circles in FIG.
1) There is no clear diffraction line other than the diffraction line corresponding to the plane,
In FIG. 2, it was found that the region surrounded by α, β, γ, δ, ε, and φ has an amorphous structure when the thin film is manufactured (As-deposit state).

Then, in order to observe the fine structure of the amorphous structure, No. 1 in FIG. High-resolution TEM observation was performed on the film having the composition of 15. In TEM observation, etching is performed from the surface side and the substrate side of the thin film, and the structure near the midpoint in the thickness direction of the thin film is observed. According to this, the lattice image could not be recognized even at the resolution of 0.3 nm. The thin film sample was subjected to selected area electron diffraction in a region with a diameter of about 200 nm, and the observed diffraction ring showed a very wide halo pattern, indicating that the thin film has a very high amorphous property.

Next, the dielectric characteristics will be described. First,
FIG. 6 shows the change in the dielectric hysteresis loop on the dotted line A in FIG. No. on the same line. In the film of No. 7, the thin film became conductive, and the dielectric characteristics could not be evaluated. The number on the left shoulder of the hysteresis loop in FIG. 6 is
It corresponds to the number indicating the composition in FIG. As is clear from this result and the result of the structural analysis of FIG.
o. 10, No. 15, No. It was found that the thin film of 18 exhibits ferroelectricity while having an amorphous structure. In addition, the thin film composition on the straight line A in FIG.
(0.5Fe ₂ O ₃ -0.5SiO ₂ )-(1-y) L
When expressed as iTaO ₃ , the dependency of the saturation charge density (Ps) of the thin film on y was shown. From the hysteresis loop of the dielectric characteristics shown in FIG.
The electric field dependency of the electric flux density (D) at 500 kV / cm was extrapolated to the E = 0 axis, and the electric flux density at the point intersecting with the coaxial was defined as the saturated charge density. It can be seen that Ps is present over a wider composition range than in FIG. 7 and the thin film exhibits ferroelectricity, but on the same line, the ferroelectricity disappears in a composition region close to LiTaO ₃ . Understand. It is considered that the phase precipitated in this composition region is not the ferroelectric phase but the paraelectric phase. Also, FIG. 2, line B
The composition dependence of the hysteresis loop was also shown for each composition (Fig. 8). The numbers on the left shoulder of the hysteresis loop in FIG. 8 correspond to the numbers indicating the composition in FIG. As is clear from this, it is clear that ferroelectricity is observed in the thin films in all compositions. The saturation charge density (Ps) was obtained by the method described above from this hysteresis loop. The composition change of the straight line B is 0.80 (xS
_{iO 2 - (1-x)} Fe 2 O 3) -0.20LiTaO
It is expressed by the notation ₃ . The dependence of Ps on x is shown in FIG.
It was shown to. As can be seen from the figure, it can be seen that Ps exists for all x values and exhibits ferroelectricity. Further, the dielectric characteristics and the structure by X-ray were evaluated for the compositions of all the thin films shown in FIG. The results are shown together in the figure. That is, in the figure, the black circles represent the composition of the thin film showing amorphous ferroelectricity,
The shaded circles indicate a composition that has an amorphous structure and exhibits paraelectric properties. Further, the white circles are crystalline thin films, and the thin films showed conductivity. The structure and dielectric properties of the thin films of various compositions examined on the same composition diagram are summarized. As is clear from this figure, the composition of the thin-film material that has an amorphous structure and exhibits ferroelectricity is widely distributed in the figure, and in the figure, α, β, γ,
The region surrounded by δ, ε, and φ (portion marked with thin ink) can be defined as a composition region in which ferroelectricity is exhibited while having an amorphous structure. Table 1 shows the correspondence between the thin film composition and the saturation charge density Ps for all the compositions shown in FIG. About 43 (n
It has a saturated charge density of C / cm ² ) or more, and it is found that this charge density reaches a maximum of about 132 (nC / cm ² ), and it has sufficient practical characteristics as a ferroelectric. Conceivable.

[0013]

[Table 1]

Example 2 A thin film was formed by changing the substrate to a glass substrate by the film forming method described in Example 1. No. of Corning on the glass substrate. 7059 was used. No. 2 shown in FIG. 1
5 and No. 5 A thin film having a composition of 20 was prepared. The film thickness of the sputtered thin film was about 200 nm.
The prepared thin film had an amber color. In each of the thin films, an antireflection film was applied in the near infrared region, and the light transmittance was measured. FIG. 10 shows the light wavelength dependence of the transmittance. As can be seen from this result, it is understood that the amorphous ferroelectric thin film has a light transmittance of 90% or more in the near infrared region, and that the thin film can be applied to an electro-optical element.

Example 3 A thin film was prepared by using LiNbO ₃ instead of ferroelectric LiTaO ₃ as the LiNbO ₃ dielectric material by the same film forming method as in Example 1. The composition of the produced thin film is shown in the triangular composition diagram of FIG. 1 and No. 1 25-No. Four
The numbers up to 8 are shown as points with additional notes. As-dep
The osit thin film was subjected to structural analysis by dielectric properties and X-rays. The results are shown together in FIG. In the figure, the black circles indicate the composition of the thin film showing amorphous ferroelectricity, and the shaded circles indicate the composition of the thin film exhibiting paraelectricity while having an amorphous structure. Further, the white circles are crystalline thin films, which indicate the composition of the thin films having conductivity. From this result, in the triangular composition diagram, α,
It was found that the region surrounded by β, γ, δ, ε, φ (portion applied with thin ink) expresses amorphous ferroelectricity in the composition region applied with thin ink. Here, it has been found that even a LiNbO ₃ material which exhibits antiferroelectricity by itself shows remarkable ferroelectricity by adding Fe ₂ O ₃ or SiO ₂ in excess. Table 2 shows a list of saturated charge densities for each composition shown in FIG. According to the table, in the SiO ₂ —Fe ₂ O ₃ —LiNbO ₃ system amorphous ferroelectric thin film, the maximum is 175 (nC / cm ² ).
Saturation charge densities on the order of were observed.

[0016]

[Table 2]

Example 4 In the M ₂ O ₃ —SiO ₂ —LiTaO ₃ system, each thin film was prepared by using the elements shown in Table 3. The thin film was manufactured by the method described in Example 1. Further, the structure evaluation of the thin film was carried out by the X-ray diffraction method under the conditions of Example 1.
Was as described in. Furthermore, the method of evaluating the dielectric properties of the thin film is the same as in Example 1. However, in the sputtering film formation, M is Zr, Mo, Pd, Hf, Ta,
In the case of W, instead of M ₂ O ₃ as a target,
Fine metal powder of each element was used. Other Sc, Ti,
V, Cr, Mn, Co, Ni, Y, Nb, In, La,
Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, H
For o, Er, Tm, Yb, and Lu, M ₂ O ₃ type oxide materials were used as targets. In addition, since Ni ₂ O ₃ contains water of crystallization, it was heated to about 200 ° C. before being used as a target, and the water of crystallization was skipped to make it anhydrous. Films having compositions indicated by circles in FIG. 12 were prepared for all M elements, and the structure and dielectric properties of the films were evaluated in the As-deposit state. In the figure, the black circles indicate the composition of the thin film showing amorphous ferroelectricity, and the shaded circles indicate the composition of the thin film exhibiting paraelectricity while having an amorphous structure. Further, the white circles are crystalline thin films, indicating the composition of the thin films that became conductive. From this result, in the triangular composition diagram, α, β, γ,
It was found that the region surrounded by δ, ε, and φ (portion with thin ink) expresses amorphous ferroelectricity in the composition region with thin ink. No. in the composition diagram Table 3 shows the saturated charge densities (Ps) measured at various M values for the film having the composition noted 49. From this, it can be understood that Ps is observed in all the thin films shown in the table and that the ferroelectric properties are exhibited in each thin film.

[0018]

[Table 3]

[0019]

As described above, M ₂ O ₃ --SiO ₂ --AB
O ₃ (ABO ₃ is LiNbO ₃ type dielectric) based thin film
Low substrate temperature, such as 2 by F sputtering method
By thinning the film at a substrate temperature of about 5 ° C., a highly translucent ferroelectric thin film having an amorphous structure can be obtained, which can be applied to a sensor, a memory, and an electro-optical element using ferroelectricity.

[Brief description of drawings]

FIG. 1 is a composition system diagram for explaining the present invention.

FIG. 2 is a composition system diagram for explaining an example of the present invention, and an explanatory diagram of dielectric properties and a thin film structure.

FIG. 3 is a structural diagram of a thin film for explaining the dielectric property evaluation method of the present invention.

FIG. 4 is an X diagram for explaining an embodiment of the present invention.
It is a line diffraction pattern.

FIG. 5 is an X-ray diffraction pattern for explaining the same example.

FIG. 6 is a diagram showing the electric field dependence of dielectric properties for explaining the same example.

FIG. 7 is a graph showing composition dependence of saturated charge density for explaining the same embodiment.

FIG. 8 is a diagram showing the electric field dependence of dielectric properties for explaining the same example.

FIG. 9 is a diagram showing composition dependence of saturated charge density for explaining the same example.

FIG. 10 is a diagram showing wavelength-independent characteristics of light transmittance for explaining the embodiment.

FIG. 11 is a composition system diagram for explaining another embodiment of the present invention, and an explanatory diagram of dielectric characteristics and a thin film structure.

FIG. 12 is a composition system diagram for explaining another embodiment of the present invention, and an explanatory diagram of dielectric characteristics and a thin film structure.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyuki Nii             5 Ube, 1978, Kogushi, Obu, Ube City, Yamaguchi Prefecture             Usan Laboratory, Kosan Co., Ltd.

Claims (4)

[Claims] 1. A transition metal oxide (M ₂ O ₃ ) -silicon oxide (SiO ₂ ) -LiNbO ₃ type compound (ABO ₃ ).
An amorphous ferroelectric oxide material comprising a ternary oxide containing as a main component, and the ternary oxide having an amorphous structure. (However, M ₂ O ₃ is S
c, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Z
At least one selected from the group consisting of oxides of r, Nb, Mo, Pd, Hf, Ta, W, In and lanthanum series elements, and ABO ₃ is LiNbO ₃ exhibiting ferroelectricity.
It is a type compound. ) 2. The ternary oxide is M ₂ O ₃ , SiO ₂ , AB.
In the composition diagram of the three components of _{O 3, aM 2 O 3 -} (1-
a) SiO _2, as well as, 0.90SiO ₂ -0.10
(BM ₂ O _3- (1-b) ABO ₃ ) and cSi
_{O 2 - (1-c)} ABO 3 and, 0.20 (dSi
_{O 2 - (1-d)} M 2 O 3) -0.80ABO 3 _{and, eABO 3 - (1-e} ) M 2 O 3 and 0.9
0M ₂ O ₃ -0.10 (fABO _3- (1-f) SiO
₂ ) In each composition line represented by 0.10 ≦ a ≦
0.90 and 0.00 ≦ b ≦ 1.00 and 0.20 ≦ c
≤ 0.90 and 0.00 ≤ d ≤ 1.00 and 0.20 ≤
The amorphous ferroelectric oxide material according to claim 1, which has a composition surrounded by six composition lines defined in a range of e ≦ 0.90 and 0.00 ≦ f ≦ 1.00. 3. The amorphous ferroelectric oxide material according to claim 1 or 2, wherein the ternary oxide is formed in the form of a thin film. 4. A ternary oxide is formed as an amorphous thin film on a substrate using a film forming means while maintaining the substrate temperature at 300 ° C. or lower, and the ferroelectric oxide is produced as it is. The method for producing an amorphous ferroelectric oxide material according to claim 3, wherein a material is obtained.