WO2020246363A1 - Dielectric film, capacitor using same, and dielectric film production method - Google Patents

Abstract

Provided is a dielectric film capable of stably maintaining a high dielectric constant across a wide temperature range (e.g., 20–150°C). The dielectric film has a pyrochlore or layered perovskite crystalline structure having a composition indicated by general formula A₂B₂O₇ (in the formula, A indicates at least two elements (mutually different A¹ and A²) selected from the group consisting of Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu and B includes at least one element (B¹) selected from the group consisting of Ti, Zr, Hf, V, Nb, and Ta.) A¹ ₂B¹ ₂O₇, which is the main component of the crystalline structure of the dielectric film, has at least one orientation plane in addition to (h00), (0k0), (00l), (h0l), and (0kl) planes (h, k, and l are integers other than 0).

Description

Dielectric film and method for manufacturing capacitors and dielectric film using it

The present invention relates to a dielectric film, a capacitor using the same, and a method for manufacturing such a dielectric film.

Previously, a single crystal having a composition represented by the general formula A ₂ B ₂ O ₇ grown by the floating zone method (for example, Sr ₂ Ta ₂ O ₇ , Sr ₂ Nb ₂ O ₇ etc.) (this is distinguished from a thin film). (Also referred to as "bulk single crystal") has been reported to exhibit dielectric properties (see Non-Patent Document 1). In connection with this report, there is also a report that the crystal structure of Sr ₂ Ta ₂ O ₇ obtained by the floating zone method is a perovskite type slab structure similar to the crystal structure of Sr ₂ Nb ₂ O ₇ (non-patent). Reference 2).

Further, a dielectric film having a pyrochlore-type crystal structure and a composition represented by the general formula A ₂ B ₂ O ₇ (for example, Sr ₂ Ta ₂ O ₇ or the like) was arranged between the two electrodes. Capacitors (thin film capacitors) are known (see Patent Document 1). Patent Document 1 describes that a dielectric film made of Sr ₂ Ta ₂ O ₇ , which is a pyrochlore-type compound, was formed by a CVD method at a substrate temperature of 400 ° C. and exhibited a relative permittivity of 600.

Further, a layered perovskite material having a composition represented by (Sr ₂ Ta ₂ O ₇ ) _100-x (La ₂ Ti ₂ O ₇ ) _x (in the formula, 0 ≦ x ≦ 5), and corresponding metal oxidation. A material prepared in the form of pellets (diameter 12 or 18 mm, thickness 0.5 mm) by a two-step solid phase reaction using a material powder raw material is also known (see Non-Patent Document 3). It has been reported that the relative permittivity of this material changes significantly in the temperature range of 20 to 300 ° C. (see FIG. 7 of Non-Patent Document 3).

Japanese Unexamined Patent Publication No. 10-178153

Capacitors used for electronic components, etc. have stable electrical characteristics over a wide temperature range, for example, room temperature of about 20 ° C. or relatively high temperature of about normal temperature to about 150 ° C., preferably high temperature of about 300 ° C. It is required to show, and above all, it is desirable to stably maintain a high relative permittivity over such a temperature range. However, it has been found by the studies of the present inventors that the above-mentioned conventional capacitors and materials cannot stably maintain a high relative permittivity over such a temperature range.

The present invention provides a dielectric film capable of stably maintaining a high relative permittivity over a wide temperature range (for example, 20 to 150 ° C.), a capacitor using the same, and a method for producing such a dielectric film. The purpose is.

The present inventors have obtained an original idea of controlling the orientation plane of a dielectric film having a composition represented by the general formula A ₂ B ₂ O ₇ , and have completed the present invention as a result of further diligent research. I arrived.

According to one gist of the present invention, a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure.
General formula A ₂ B ₂ O ₇ (In the formula, A is Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb. Two or more elements selected from the group consisting of and Lu, each containing A ¹ and A ² different from each other, where B is from Ti, Zr, Hf, V, Nb and Ta. and one or more elements selected from the group consisting having a composition represented by the among containing B ¹ as one element),
Of all the combinations of A ₂ B ₂ O ₇ obtained stoichiometrically by selecting one of each of the elements A and B existing in the dielectric film, the main component of the crystal structure of the dielectric film. With respect to A ¹ ₂ B ¹ ₂ O ₇ forming the above, in addition to the faces (h00), (0k0), (00l), (h0l) and (0kl) (h, k and l are integers excluding 0). A dielectric film having at least one orientation plane is provided.

According to another gist of the present invention, a capacitor including an electrode and the dielectric film of the present invention arranged on the electrode is provided.

According to yet another gist of the present invention, it is a method for producing a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure.
(A) On the surface of the substrate heated to a temperature of 350 to 600 ° C., the general formula A ₂ B ₂ O ₇ (in the formula, A is Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm. , Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, two or more elements selected from the group, each of which is different from each other, A ¹ and A ^2. B is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta, and B ¹ is included as one of the elements). The precursor film to have is formed by vapor phase deposition, and (b) the substrate on which the precursor film is formed is heat-treated at a temperature of 850 to 1050 ° C. in an atmosphere containing oxygen to form the precursor film. To provide a production method comprising obtaining a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure and having the above composition.

According to the present invention, in a dielectric film having a pyrochloroa type or layered perovskite type crystal structure, at least two elements of A site having a composition represented by the general formula A ₂ B ₂ O ₇ are present, and further. With respect to A ¹ ₂ B ¹ ₂ O ₇ which is the main component of the crystal structure of the dielectric film, the planes (h, k and l) of (h00), (0k0), (00l), (h0l) and (0kl) are 0. By having at least one orientation plane in addition to (an integer excluding), a dielectric film capable of stably maintaining a high relative permittivity over a wide temperature range (for example, 20 to 150 ° C.) is provided. To. Further, according to the present invention, a capacitor using such a dielectric film and a method for producing such a dielectric film are also provided.

FIG. 5 is a schematic cross-sectional view showing an exemplary embodiment of a capacitor in one embodiment of the present invention. The two-dimensional X-ray diffraction image of the dielectric film of Example 1 is shown. (A) schematically shows the integration direction (χ direction) when converting the two-dimensional X-ray diffraction image of the dielectric film of Example 1 into an X-ray diffraction pattern (one-dimensional profile), and (b) is. , The X-ray diffraction pattern (one-dimensional profile) obtained thereby is shown. The measurement data of the X-ray diffraction pattern (one-dimensional profile) of the dielectric film of Example 1 and the data which fitted this by the Gaussian function are shown. (A) schematically shows the integration direction (2θ direction) when the two-dimensional X-ray diffraction image of the dielectric film of Example 1 is converted into a one-dimensional profile with respect to the spot of the orientation plane, and (b) is. The measurement data of the one-dimensional profile about the spot of the orientation plane of the dielectric film of Example 1 and the data which fitted this with the Gauss function are shown. It is a graph which evaluated the electrical property of the dielectric film of Example 1. A two-dimensional X-ray diffraction image of the dielectric film of Example 2 is shown. It is a graph which evaluated the electrical property of the dielectric film of Example 2. A two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 1 is shown. A two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 2 is shown. A two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 3 is shown. It is a graph which evaluated the electrical property at room temperature of the dielectric film in Comparative Examples 1 to 3 and the modified example thereof. (A) shows a two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 4, and (b) shows an X-ray diffraction pattern (1) of Comparative Example 4 (shown at "900 ° C.") and its modified example. Dimensional profile) is shown. It is a graph which evaluated the electrical property of the dielectric film of the comparative example 4. (A) shows a two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 5, and (b) shows an X-ray diffraction pattern (1) of Comparative Example 5 (shown at "900 ° C.") and its modified example. Dimensional profile) is shown. It is a graph which evaluated the electrical property of the dielectric film of the comparative example 5. (A) shows a two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 6, and (b) shows an X-ray diffraction pattern (1) of Comparative Example 6 (shown at "900 ° C.") and its modified example. Dimensional profile) is shown. (A) shows a two-dimensional X-ray diffraction image of the dielectric film of Comparative Example 7, and (b) shows an X-ray diffraction pattern (1) of Comparative Example 7 (shown at "900 ° C.") and its modified example. Dimensional profile) is shown. The X-ray diffraction pattern (one-dimensional profile) of the dielectric film of Comparative Example 8 is shown. The X-ray diffraction pattern (one-dimensional profile) of the dielectric film of Comparative Example 9 is shown.

(Embodiment 1: Dielectric film and its manufacturing method)
According to one embodiment of the present invention, a dielectric film and a method for producing the same are provided.

The dielectric film of this embodiment is
It has a pyrochlore-type or layered perovskite-type crystal structure.
General formula A ₂ B ₂ O ₇ (In the formula, A is Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb. Two or more elements selected from the group consisting of and Lu, each containing A ¹ and A ² different from each other, where B is from Ti, Zr, Hf, V, Nb and Ta. and one or more elements selected from the group consisting having a composition represented by the among containing B ¹ as one element),
Of all the combinations of A ₂ B ₂ O ₇ obtained stoichiometrically by selecting one of each of the elements A and B existing in the dielectric film, the main constituent of the crystal structure of the dielectric film. With respect to A ¹ ₂ B ¹ ₂ O ₇ forming, other than the faces (h00), (0k0), (00l), (h0l) and (0kl) (h, k and l are integers excluding 0). It has at least one orientation plane.

The crystal structure of the oxide having the composition represented by the general formula A ₂ B ₂ O ₇ can usually be a pyrochlore type or a layered perovskite type (also referred to as a perovskite type slab) (these polymorphs can be adopted). Including cases). However, what kind of crystal structure the oxide has may differ depending on its specific composition, production method, etc., and further changes depending on conditions such as temperature and pressure to which the oxide is exposed (for example, phase). Can change and / or transfer between polymorphs). Therefore, in the present invention, the "pyrochlore-type or layered perovskite-type crystal structure" means a crystal structure that may be either one or both of them, and is not construed as being limited to only one of them.

The dielectric film of the present embodiment has a composition represented by the general formula A ₂ B ₂ O ₇ . A and B are symbols that mean (or generically) the elements that occupy the A site and the B site, respectively, in the pyrochlore type or layered perovskite type crystal structure.

A is two or more selected from the group consisting of Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. Contains the elements of. Preferably, A comprises two or more elements selected from the group consisting of Sr, Ba, La and Nd. There are two or more specific elements that correspond to A, and these are referred to as A ¹ and A ² (these are different from each other).

B comprises one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta. Preferably, B comprises one or more elements selected from the group consisting of Ti, Nb and Ta. There is one or more specific elements corresponding to B, and this is referred to as B ¹ (Note that B ² described later is also a specific element corresponding to B, but B ² is the same as B ¹ . It may or may not be different).

Stoichiometrically, A ₂ B ₂ O ₇ is, for example, when A is an element having a trivalent valence and B is an element having a tetravalent valence (that is, A (III) ₂ ). B (IV) ₂ O ₇ type), when A is an element having a divalent valence and B is an element having a pentavalent valence (that is, A (II) ₂ B (V) ₂ O ₇ ) Type), and when these are mixed, etc.

Of all the combinations of A ₂ B ₂ O ₇ obtained (or conceivable) stoichiometrically by selecting one of each of the elements A and B present in the dielectric film, the dielectric film A ¹ ₂ B ¹ ₂ O ₇ which is the main component of the crystal structure is identified, and each element of A ¹ and B ¹ is specifically determined by this. That is, in the dielectric film of the present embodiment, it can be understood that A ¹ ₂ B ¹ ₂ O ₇ forms the main body of the crystal structure, and A ² and other elements that may exist are dissolved therein. ..

In the present invention, A ¹ ₂ B ¹ ₂ O ₇ "forms the main body of the crystal structure" of the dielectric film means that A ¹ ₂ B ¹ ₂ O ₇ mainly bears the crystal structure of the dielectric film. means. Which of all the combinations of A ₂ B ₂ O ₇ is "mainly responsible for the crystal structure" A ¹ ₂ B ¹ ₂ O ₇ is determined based on the X-ray diffraction pattern obtained from the dielectric film. It is determined to show the crystal structure closest to the crystal structure of the dielectric film.

For example, in the case of a dielectric film in which A ₂ B ₂ O ₇ is (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ (in the formula, 0 <x <1), it corresponds to A. All combinations obtained stoichiometrically by selecting one each of Sr and La corresponding to B and Ta and Ti corresponding to B are Sr ₂ Ta ₂ O ₇ and La ₂ Ti ₂ O ₇ ( Note that these elements (valences) are Sr (II), La (III), Ta (V), Ti (IV)). Which of these Sr ₂ Ta ₂ O ₇ and La ₂ Ti ₂ O ₇ "forms the main body of the crystal structure" depends on the X-ray diffraction pattern obtained from the dielectric film and Sr ₂ Ta ₂ O ₇ and La ₂ By comparing the known powder X-ray diffraction data for each of Ti ₂ O ₇ , the one corresponding to the powder X-ray diffraction data closest to the X-ray diffraction pattern of the dielectric film (for example, Sr ₂ Ta ₂ O ₇ ) is obtained. , A ¹ ₂ B ¹ ₂ O ₇ (for example, A ¹ is Sr and B ¹ is Ta) which form the main body of the crystal structure.

Known powder X-ray diffraction data can be obtained and used from a database provided by, for example, ICDD (International Center for Diffraction Data). The X-ray diffraction pattern of the dielectric film is obtained by converting a two-dimensional X-ray diffraction image obtained by using a two-dimensional detector into a one-dimensional profile (arc integration in the χ direction in a region of a detection angle χ = 38 °). In the identification, a substance other than the dielectric film (for example, a substance forming the base of the dielectric film, specifically, a substrate or a conductive member for an electrode if present) may be used. ), It is necessary to ignore the peak, and it is preferable to consider the orientation plane described later. These explanations also apply to the following explanations in the same manner unless otherwise specified.

In the present invention, the "alignment plane" of the dielectric film means a plane parallel to the surface of the dielectric film, which is highly oriented, that is, highly crystalline, and more specifically, two-dimensional X-ray diffraction. It is a surface observed in a spot shape in an image, and its surface index (Miller index) is determined with respect to A ¹ ₂ B ¹ ₂ O ₇ which is the main component of the crystal structure. The dielectric film of the present embodiment, such alignment surface may have one or more, but with respect to A ¹ ₂ B ¹ ₂ O ₇ constituting the main body of the crystal structure of the dielectric film, (h00), In addition to the planes (0k0), (00l), (h0l) and (0kl) (h, k and l are integers excluding 0), it has at least one orientation plane.

For example, when A ¹ ₂ B ¹ ₂ O ₇ which forms the main body of the crystal structure is Sr ₂ Ta ₂ O _7, it is one or more observed in the two-dimensional X-ray diffraction image of the dielectric film. The diffraction angle (2θ) of a good spot is measured, and on which surface in the powder X-ray diffraction data known for Sr ₂ Ta ₂ O ₇ that the diffraction angle (2θ) of the spot is A ¹ ₂ B ¹ ₂ O _7. By examining the coincidence, the plane index of one or more oriented planes observed as the spot is determined. The plane index of at least one orientation plane thus determined is (h00), (0k0), (00l), (h0l) and (h0l) of Sr ₂ Ta ₂ O ₇ of A ¹ ₂ B ¹ ₂ O _7. Any surface other than the plane (0 kl) (h, k and l are integers excluding 0) may be used. The diffraction angle (2θ) of the spot uses a one-dimensional profile obtained by converting a two-dimensional X-ray diffraction image (preferably, the region of the detection angle χ = 38 ° is converted by arc integration in the χ direction). The measurement may be performed based on the peak corresponding to the spot.

The dielectric film of the present embodiment has (h,), (0k0), (00l), (h0l) and (0kl) planes (h,) with respect to A ¹ ₂ B ¹ ₂ O ₇ which is the main component of the crystal structure. In addition to (k and l are integers excluding 0), it has at least one orientation plane. This means that the b-axis direction of the crystals forming the dielectric film is not orthogonal to the surface of the dielectric film and is tilted.

By having the orientation plane as described above, the dielectric film of the present embodiment stably maintains a high relative permittivity over a wide temperature range (for example, 20 to 150 ° C., preferably 20 to 300 ° C.). That is, it can be maintained at a small rate of change. The present invention is not bound by any theory, the reason for which can be considered as follows. A dielectric film having a pyrochlore-type or layered perovskite-type crystal structure is provided in the a-axis direction, the b-axis direction, and the c-axis direction in a temperature range of 20 to 150 ° C., more broadly, in a temperature range of 20 to 300 ° C. The magnitude of the relative permittivity and the temperature dependence are different. More specifically, although it depends on the composition of the dielectric film, in such a temperature range, the relative permittivity in the a-axis direction and the c-axis direction is higher than the permittivity in the b-axis direction, and a stable slight increase tendency is exhibited. Although shown, the Curie temperature in the a-axis direction and the c-axis direction (the temperature at which the non-dielectric constant rises sharply and shows a peak) is in a high temperature region considerably distant from such a temperature range, while in the b-axis direction. Curie temperature is in a low temperature range, not close to such a temperature range. From this, by tilting the b-axis direction of the crystal with respect to the surface of the dielectric film, the relative permittivity of the a-axis direction and the c-axis direction is utilized while utilizing the increase in the relative permittivity due to the contribution in the b-axis direction. It is thought that the stability of can be combined. It is considered that the effect of such a combination can be remarkably generated when two or more elements of A site are used. Therefore, the number of elements at the A site is two or more, and A ² and other elements that may exist are dissolved in A ¹ ₂ B ¹ ₂ O ₇ which is the main component of the crystal structure, and the surface of the dielectric film is By tilting the b-axis direction of the crystal, it is considered possible to obtain a higher and stable relative permittivity in the temperature range of 20 to 150 ° C., preferably 20 to 300 ° C.

The at least one orientation plane of the dielectric film of the present embodiment is (h00), (0k0), (00l), (h0l) as described above with respect to A ¹ ₂ B ¹ ₂ O ₇ which is the main body of the crystal structure. ) And (0 kl) planes. Such at least one orientation plane is, for example, (111), (131), (151), (115 1), (192), (153), (157), (110), (150), (212). , (172) and (1 130), and the like, but not limited to any one or more. In the present specification, when h, k and l are all one-digit integers, they are shown according to the notation of (hkl), but when at least one of them is an integer of two or more digits, between integers. Is shown with a space.

Furthermore, the at least one orientation face of the dielectric film of the present embodiment, for ^A ₁ 2 ^B ₁ 2 _{O 7} constituting the main body of the crystal structure, other than the above-mentioned surface, and the surface of the (hk0) (h, It is preferable that k and l are planes other than 0). As a result, the b-axis direction of the crystal can be more appropriately tilted with respect to the surface of the dielectric film. Such at least one orientation plane is, for example, any one of (111), (131), (151), (115 1), (192), (153), (157), (212) and (172). It may be one or more, but is not limited to this.

The degree of orientation of at least one of the orientation planes is preferably 0.5 or more and 1 or less, and more preferably 0.8 or more and 1 or less. This makes it possible to orient the dielectric film on this orientation plane at a high rate.

In the present invention, the "degree of orientation" of a predetermined orientation plane is defined by the Lotgering factor f (-). The lotgering factor f is calculated by the following equation (1) using the intensity of X-rays diffracted from a predetermined orientation plane (conveniently referred to as (xyz)).
f = (pp ₀ ) / (1-p ₀ ) ... (1)
In formula (1), p ₀ is a value based on known powder X-ray diffraction data for A ¹ ₂ B ¹ ₂ O ₇ identified as being the main component of the crystal structure, and p is the X-ray of the dielectric film. It is a value based on the diffraction pattern, and is obtained by the following equations (2) and (3), respectively.
p ₀ = I ₀ (xyz) / ΣI ₀ (hkl) ・ ・ ・ (2)
p = I (xyz) / ΣI (hkl) ・ ・ ・ (3)
In equations (2) and (3), h, k, and l are integers including 0.
In formula (2), ΣI ₀ (hkl) is the diffraction intensity of the peaks of all surfaces obtained from the known powder X-ray diffraction data for A ¹ ₂ B ¹ ₂ O ₇ (usually, the maximum intensity is 100). Relative intensity) means the sum of I ₀ (xyz) of the diffraction intensity (ibid.) Of the peak of the predetermined orientation plane (xyz) obtained from the known powder X-ray diffraction data for A ¹ ₂ B ¹ ₂ O ₇ . Means a value.
In the formula (3), ΣI (hkl) means the sum of the diffraction intensities of the peaks of all the surfaces obtained from the X-ray diffraction pattern of the dielectric film, and I (xyz) is the X-ray diffraction pattern of the dielectric film. It means the value of the diffraction intensity of the peak of the predetermined orientation plane (xyz) obtained from. The X-ray diffraction pattern of the dielectric film used in the formula (3) converts a two-dimensional X-ray diffraction image obtained by using a two-dimensional detector into a one-dimensional profile (for a region of a detection angle χ = 38 °). It is preferable to perform arc integration in the χ direction for conversion), and use the Gaussian function fitting of each peak of the obtained one-dimensional profile (however, peaks caused by substances other than the dielectric film are excluded). , The sum of the diffraction intensity areas of all the peaks after fitting is applied as the sum of the diffraction intensities of the peaks of all the surfaces, and the value of the diffraction intensity of the peaks of the predetermined orientation plane (xyz) is a predetermined value after fitting. The value of the diffraction intensity area of the peak of the orientation plane (xyz) is applied.

Further, in the at least one orientation plane, the variation in the inclination of the crystal axis is preferably 10 ° or less, and more preferably 1 ° or less. As a result, the dielectric film can be oriented with high crystallinity on this orientation plane.

In the present invention, the "variation in the inclination of the crystal axis" of the predetermined alignment plane is the half width (°) of the peak of the orientation plane (conveniently referred to as (xyz)) obtained from the X-ray diffraction pattern of the dielectric film. ). In the X-ray diffraction pattern of the dielectric film used here, the portion of the two-dimensional X-ray diffraction image obtained by using the two-dimensional detector that corresponds to the predetermined orientation plane (xyz) is converted into a one-dimensional profile. (It is preferable to integrate and convert the arc region including the spot of the predetermined orientation plane (xyz) in the 2θ direction), and the peak of the predetermined orientation plane (xyz) of the obtained one-dimensional profile was fitted by a Gaussian function. The half-value width (°) of the peak of a predetermined orientation plane (xyz) after fitting is measured by using a device.

In the dielectric film of the present embodiment, the content ratio of A ^{1 to} the total amount of A can be less than 50 atomic%. Although A ¹ is an element that forms the main component of the crystal structure, the upper limit of its content ratio can be less than 50 atomic%, preferably 40 atomic% or less, more preferably 30 atomic% or less, still more preferably. It was found by the research of the present inventors that it was 20 atomic% or less. The lower limit of the content ratio of A ¹ can be 5 atomic% or more, preferably 10 atomic% or more in order to form the main body of the crystal structure.

In the dielectric film of the present embodiment, the content ratio of A ^{2 to} the total amount of A can be 50 atomic% or more. Although A ² is an element that does not form the main component of the crystal structure and is solid-solved in A ¹ ₂ B ¹ ₂ O ₇ , the lower limit of its content ratio can be 50 atomic% or more, which is preferable. Was found to be 60 atomic% or more, more preferably 70 atomic% or more, still more preferably 80 atomic% or more, according to the research by the present inventors. The upper limit of the content ratio of A ² can be 95 atomic% or less, preferably 90 atomic% or less so that it can be dissolved in A ¹ ₂ B ¹ ₂ O ₇ .

The content ratio of each element in the dielectric film can be measured by fluorescent X-ray analysis and / or photoelectron spectroscopy.

According to the research by the present inventors, it has been found that it is important that two or more elements of the A site of A ₂ B ₂ O ₇ are present in order to control the orientation plane of the dielectric film. On the other hand, the number of elements at the B site has less or substantially no effect on the control of the orientation plane of the dielectric film.

The two elements of the A site, A ¹ and A ² , preferably have different valences from each other. It is considered that the orientation plane of the dielectric film can be remarkably controlled by the presence of two elements having different valences.

For example, A ¹ may be a divalent element, typically Sr, and A ² may be a trivalent element, typically La, but is not limited to such combinations.

The dielectric film of the present embodiment can maintain a high relative permittivity stably, that is, with a small rate of change over a wide temperature range (for example, 20 to 150 ° C., preferably 20 to 300 ° C.). The relative permittivity of the dielectric film of the present embodiment ranges from 20 to 150 ° C., preferably 20 to 300 ° C., and the relative permittivity of the bulk single crystal having the same composition (more specifically, the bulk single crystal having the same composition). (Relative permittivity in the a, b, and c axis directions), for example, 70 or more, more preferably 80 or more, particularly preferably 100 or more, and the upper limit is not particularly limited, but for example, 400. It can be: The rate of change of the relative permittivity of the dielectric film of the present embodiment is preferably 20 to 150 ° C., preferably 20 to 300 ° C., and may be, for example, 10% or less based on the relative permittivity at 20 ° C. Can be less than or equal to 5%.

The dielectric film of the present embodiment may have an arbitrary appropriate thickness, but may be a thin film. The thickness of the dielectric film of the present embodiment can be, for example, 3 nm or more and 1 μm or less. The lower limit is preferably 10 nm or more, and more preferably 50 nm or more from the viewpoint of ensuring insulation (for example, effectively preventing the occurrence of pinholes). The upper limit may be 10 μm or less, but in practice it can be 1 μm or less, preferably 500 nm or less.

The dielectric film of the present embodiment may be produced by any suitable method, and can be produced by, for example, the following method.

The method for producing a dielectric film of the present embodiment is a method for producing a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure.
(A) On the surface of the substrate heated to a temperature of 350 to 600 ° C., the general formula A ₂ B ₂ O ₇ (in the formula, A is Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm. , Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, two or more elements selected from the group, each of which is different from each other, A ¹ and A ^2. B is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta, and B ¹ is included as one of the elements). The precursor film to have is formed by vapor phase deposition, and (b) the substrate on which the precursor film is formed is heat-treated at a temperature of 850 to 1050 ° C. in an atmosphere containing oxygen, and the precursor film is formed. The present invention comprises obtaining a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure and having the above composition.

According to the research by the present inventors, in order to bring a crystal structure to the dielectric film and control the orientation plane thereof, the temperature at which the substrate is heated in the above step (a) (hereinafter, also simply referred to as “substrate temperature”). , And the temperature at which the substrate on which the precursor was formed is heat-treated in the above step (b) (hereinafter, also simply referred to as “PDA temperature” (PDA: Post Deposition Annealing)) was found to be important (of the dielectric film). Crystallization is considered to proceed not only in step (a) but also in step (b)). According to the method for producing a dielectric film of the present embodiment, the substrate is heated at a temperature of 350 to 600 ° C., preferably 400 to 500 ° C. in the above step (a), and a precursor is formed in the above step (b). By heat-treating the obtained substrate at 850 to 1050 ° C., preferably 850 to 950 ° C., the dielectric film of the present embodiment having the orientation plane as described above can be obtained.

In the step (a) of the method for producing a dielectric film of the present embodiment, the material and structure of the substrate are not particularly limited, and can be appropriately selected depending on the use of the dielectric film and the like. For example, the substrate may consist of a single material. Further, for example, even if the substrate has a conductive member (which can be used as an electrode, but is not limited to) in advance on the surface thereof, and a precursor film is formed on the conductive member of the substrate by vapor deposition. Good. When the substrate and / or the conductive member in contact with the dielectric film is made of a crystalline material, the surface thereof is preferably the surface (111) or (001). As a result, the relative permittivity of the dielectric film can be maintained high and stable.

In step (a) above, vapor deposition is more specifically physical vapor deposition including sputtering (eg, high frequency (RF) sputtering, pulsed DC sputtering), electron beam deposition, ion plating, and / or metalorganic vapor phase. It can be carried out by applying a growth method (so-called MOCVD, including, for example, atomic layer volumetric method (ALD)), but is not limited thereto.

In the above step (a), A ₂ B ₂ O ₇ is A ¹ ₂ B ¹ ₂ O ₇ and A ² ₂ B ² ₂ O ₇ (in the formula, A ¹ , A ² and B ¹ are as described above. , ^{B 2} is, Ti, Zr, Hf, V , a single element of Nb and Ta, are the same or different elements as ^{B 1,} comprises a preferably ^{B 1} to be different elements), ^{a 1} It is preferred that ₂ B ¹ ₂ O ₇ have a lower crystallization temperature than A ² ₂ B ² ₂ O ₇ . In the dielectric film obtained by lowering the crystallization temperature of A ¹ ₂ B ¹ ₂ O ₇ than the crystallization temperature of A ² ₂ B ² ₂ O ₇ , A ¹ ₂ B ¹ ₂ O ₇ is the main component of the crystal structure. Can be made.

In the present invention, the "crystallization temperature" of an oxide represented by the general formula A ₂ B ₂ O ₇ and having a predetermined composition is (1) of a conductive substrate made of a crystalline material heated to a certain temperature T. 111) A precursor film having the predetermined composition is formed on the surface by vapor phase deposition, and a substrate on which the precursor film is formed is subjected to an oxygen gas flow rate of 0.5 L / min under atmospheric pressure. A dielectric film is obtained from the precursor film by heat treatment at a temperature of 900 ° C. for 5 minutes, and the dielectric film is subjected to two-dimensional X-ray diffraction analysis. It shall refer to the lowest temperature T at which at least one spot or ring is observed in the X-ray diffraction image. Spots observed in the two-dimensional X-ray diffraction image indicate the presence of a single crystal or a highly oriented crystal structure, and rings observed in the two-dimensional X-ray diffraction image indicate a polycrystalline state. It shows that it has become.

As a result of investigating each crystallization temperature of a typical oxide represented by the general formula A ₂ B ₂ O ₇ and having one element each of A site and B site in the research of the present inventors according to the above. Is shown in Table 1.

Since the dielectric films of La ₂ Zr ₂ O ₇ and Sr ₂ Nb ₂ O ₇ shown in Table 1 were crystallized when the precursor film was formed by vapor phase deposition, they are subjected to heat treatment at 900 ° C. The crystallization temperature was investigated, omitting the above.

In the above step (a), the precursor film may be formed by using one or more raw materials (or may be referred to as a vapor deposition source, a target, etc., the same applies hereinafter). When two or more raw materials are used, the material composition of each raw material may be the same or different from each other.

For example, for the vapor phase deposition in the above step (a), a first raw material having a composition of A ¹ ₂ B ¹ ₂ O ₇ and a second raw material having a composition of A ² ₂ B ² ₂ O ₇ are used. It may be carried out. In this case, different vapor phase deposition conditions can be applied to the first and second raw materials. Thereby, for example, the abundance ratio of A ¹ and A ² in the dielectric film, the content ratio of A ^{1 to} the total amount of A, and the content ratio of A ^{2 to} the total amount of A can be controlled. In this case, an additional raw material having a composition of A ₂ B ₂ O ₇ may or may not be present.

Preferably, the vapor phase deposition is carried out under the condition that the growth rate of A ² ₂ B ² ₂ O ₇ from the second raw material is larger than the growth rate of A ¹ ₂ B ¹ ₂ O ₇ from the first raw material. be able to. Thereby, for example, the abundance ratio of A ¹ / A ² in the dielectric film can be made small, the content ratio of A ^{1 to} the total amount of A can be made small, and the content ratio of A ^{2 to} the total amount of A can be greatly controlled.

More specifically, when the vapor phase deposition is carried out by high-frequency sputtering, A from the first raw material is applied by applying a condition in which the output applied to the second raw material is larger than the output applied to the first raw material. The growth rate of A ² ₂ B ² ₂ O ₇ from the second raw material can be made larger than the growth rate of ¹ ₂ B ¹ ₂ O ₇ .

The output (power) ratio applied to the first raw material of A ¹ ₂ B ¹ ₂ O ₇ and the ^second raw material of A ² ₂ B ² ₂ O ₇ can be appropriately selected depending on the raw material composition.

When two or more raw materials having different raw material compositions are used in the above step (a), vapor phase deposition of the raw materials from these raw materials on the surface of the substrate can be carried out in any appropriate manner. For example, the raw materials may be simultaneously vapor-phase-deposited on the surface of the substrate from these raw materials to form the precursor film in the form of a simultaneous mixed film. Further, for example, the raw materials are applied to the surface of the substrate from these raw materials non-simultaneously (the vapor phase deposition period from each raw material may or may not partially overlap, and is repeated regularly or irregularly. The precursor may be formed in the form of a fusion film in which these raw materials are fused with each other by vapor-phase deposition (for example, laminating). Fusion can occur spontaneously without the addition of further external energy, as crystal growth and element diffusion are brought about by the thermal energy transferred from the substrate and the kinetic energy applied to the raw material during vapor phase deposition.

In step (b) of the method for producing a dielectric film of the present embodiment, it is considered that crystallization further progresses in the film by heat-treating the precursor film (crystallization in step (b) It is understood as "additional crystallization").

In the above step (b), the heat treatment is preferably carried out in a gas atmosphere containing oxygen. The gas containing oxygen is not particularly limited, and air may be conveniently used under atmospheric pressure, or oxygen gas substantially composed of oxygen (for example, an oxygen concentration of 99% or more) may be used. .. The gas containing oxygen does not have to be flowed during the heat treatment, but it is more preferable to flow it, and in the latter case, the flow rate can be 0.1 to 1 L / min. The heat treatment time can be appropriately selected, and can be, for example, 2 minutes or more and 60 minutes or less.

Although the method for producing the dielectric film of the present embodiment has been described in detail above, the dielectric film of the present embodiment is not limited to that obtained by such a manufacturing method, and can be obtained by any other suitable manufacturing method. It may be a product. For example, as a method for forming a precursor film, for example, a sol-gel method may be used instead of the vapor phase deposition method.

(Embodiment 2: Capacitor and manufacturing method thereof)
According to another embodiment of the present invention, a capacitor and a method for manufacturing the capacitor are provided.

The capacitor of the present embodiment includes an electrode and a dielectric film described in detail in the first embodiment arranged on the electrode. Such a capacitor can be a so-called thin film capacitor.

The capacitor of the present embodiment may have any suitable configuration as long as it includes an electrode and a dielectric film arranged on the electrode, and is not particularly limited. For example, as shown in FIG. 1, the capacitor 10 may be configured by sandwiching the dielectric film 5 between the two electrodes 3 and 7 (in the embodiment (parallel plate type) shown in FIG. 1, the electrodes 3 and 7 are , Can be individually connected to leader wires at appropriate locations in the depth direction (not shown). Further, for example, a capacitor may be formed by providing a dielectric film straddling two electrodes existing apart from each other.

The capacitor manufacturing method of the present embodiment may be manufactured by any suitable method, but can be typically carried out including the dielectric film manufacturing method described in detail in the first embodiment. For example, in the embodiment shown in FIG. 1, the lower electrode 3, the dielectric film 5, and the upper electrode 7 may be sequentially laminated and formed on the surface of the substrate 1 to manufacture the capacitor 10. Further, for example, two electrodes may be formed on the surface of the substrate so as to be separated from each other, and a dielectric film may be formed so as to straddle them to manufacture a capacitor. The method for forming the dielectric film corresponds to the manufacturing method detailed in the first embodiment, and the method for forming the electrode may be any known suitable method.

The conductive materials constituting the electrodes are, for example, Pt, Ti, W, Al, Ni, Ag, Au, Pd, Ir, Rh, TiC, TaC, TiN, Ag ₂ O, Ru, Ru ₂ O, SrRuO ₃ , Nb. It may be added SrTiO _3, or the like, and may be, for example, one layer or a laminate of two or more layers. The material constituting the substrate is not particularly limited, for example Si, or and the like oxide single crystals such as SrTiO _3. Any suitable material layer, such as the SiO ₂ layer, may be present between the substrate and the electrodes.

The capacitor of the present embodiment has the same effect as the dielectric film described in detail in the first embodiment.

In the capacitor of the present embodiment, the surface of the electrode in contact with the dielectric film is preferably the surface of (111) or (001), for example. More specifically, when the electrode is made of a crystalline material, the preferred orientation exhibited by the surface of the electrode may differ depending on the crystal structure of the crystalline material. For example, at least according crystallinity material, cubic material (e.g. Pt, W, Al, Ni, Ag, Au, Pd, Ir, Rh, TiC, TaC, is selected from the group consisting of TiN and Ag ₂ O, etc. If it is one), if a tetragonal materials (e.g. Ru ₂ O, etc.), or is a perovskite oxide (cubic) (e.g. SrRuO _3, Nb added SrTiO _3, etc.), surface ( 111) Orientation is preferable, and in the case of a hexagonal material (for example, Ti, Ru), the surface is preferably (001) orientation. As a result, the relative permittivity of the dielectric film can be maintained high and stable.

(Example 1)
This embodiment relates to a dielectric film having a composition represented by (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ and a capacitor including such a dielectric film.

-Manufacturing procedure Formation of lower electrode A Si (100) substrate having a SiO ₂ film with a thickness of about 300 nm on its surface is prepared, and a Ti layer with a thickness of about 10 nm and a thickness of about 100 nm are formed on the surface by DC sputtering. The Pt layers were sequentially laminated to form a lower electrode composed of these layers. During DC sputtering, the temperature of the substrate was set to room temperature (about 20 ° C.). The Ti layer was provided as a relatively thin layer in order to improve the adhesion between the SiO ₂ film and the Pt layer. The Pt layer is the main body portion of the lower electrode, whereby the electrode surface of the (111) plane is formed.

Step (a): Formation of precursor film The substrate on which the lower electrode is formed as described above is heated to 400 ° C. (that is, the substrate temperature is 400 ° C.), and then RF sputtering is performed on the substrate (Sr _x La _{1-). x} ) ₂ (Ta _x Ti _1-x ) A precursor film having a composition represented by ₂ O ₇ was formed (note that a part (end) of the lower electrode did not form a precursor on it. I left it exposed). RF sputtering uses the target of the Sr ₂ Ta ₂ O ₇ raw material and the target of the La ₂ Ti ₂ O ₇ raw material as the vapor deposition source, and determines the RF power ratio of the Sr ₂ Ta ₂ O ₇ raw material: La ₂ Ti ₂ O ₇ raw material. It was vapor-deposited at the same time as 20W: 60W. The oxygen concentration in the ambient atmosphere of the substrate was 5%.

Step (b): Formation of a dielectric film by heat treatment The substrate on which the precursor film was formed as described above is subjected to heat treatment at 900 ° C. for 5 minutes while oxygen gas is allowed to flow at 0.5 L / min. (I.e., PDA temperature 900 ° C.), a dielectric film having a composition represented by (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ is formed from the precursor film. did. The thickness of the obtained dielectric film was about 200 nm.

Formation of Upper Electrode On the dielectric film formed as described above, a Pt layer having a thickness of about 150 nm was formed as an upper electrode in a substantially circular shape having a diameter of about 110 nm by DC sputtering. During DC sputtering, the temperature of the substrate was set to room temperature (about 20 ° C.). As a result, a capacitor in which the dielectric film was arranged between the lower electrode and the upper electrode was obtained.

-Analysis and evaluation Composition The content ratio of each element in the dielectric film was investigated by photoelectron spectroscopy. As a result, it was found that the dielectric film had a composition of (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ , and x = 0.35 in the formula.

A two-dimensional X-ray diffraction image of this dielectric film was obtained using a two-dimensional detector for the main body and orientation plane of the crystal structure (characteristic X-ray: CuKα = 1.5418 Å, the same applies hereinafter). The results are shown in FIG. 2 (Note that FIG. 2 illustrates a case where 2θ has a low angle of about 50 ° or less, but a case where 2θ (not shown) has a high angle of about 50 ° to 80 was also obtained. The same applies below). Further, this two-dimensional X-ray diffraction image is arc-integrated in the χ direction in the region of the detection angle χ = 38 ° in the dotted line region schematically shown in FIG. 3A, and converted into a one-dimensional profile. An X-ray diffraction pattern of the dielectric film was obtained. The results are shown in FIG. 3 (b). In FIG. 3B, the symbol “*” indicates a peak caused by a substance other than the dielectric film (Pt, Ti, SiO ₂ and Si) and is ignored because it does not constitute the dielectric film (described later). The same applies to FIGS. 13 (b), 15 (b), 17 (b), 19 (b), 21, and 22), and the peak near 2θ = 40 ° is due to Pt). From these results, the dielectric film of this example was compared with the known powder X-ray diffraction data (ICDD) of Sr ₂ Ta ₂ O ₇ and La ₂ Ti ₂ O ₇ (the following examples and comparative examples). The known data used in the above are appropriately selected depending on the raw materials used as the deposition source), and it was identified that Sr ₂ Ta ₂ O ₇ is the main component of the crystal structure. Furthermore, since spots were observed near 2θ = 28 ° in the two-dimensional X-ray diffraction image shown in FIG. 2, it was found that the dielectric film of this example had the orientation plane of (111). (In FIG. 2, the spot near 2θ = 40 ° is due to Pt).

Orientation degree of orientation plane Each peak (however, peaks caused by substances other than the dielectric film are excluded) was fitted by a Gaussian function from the X-ray diffraction pattern (one-dimensional profile) of the dielectric film obtained above. The results are shown in FIG. 4 (in the figure, the measurement data of the one-dimensional profile is shown by a solid line, and the data fitted by the Gaussian function is shown by a dotted line). From this fitting, p was calculated by calculating the ratio of the diffraction intensity area of the peak of the orientation plane (111) to the sum of the diffraction intensity areas of all the peaks. Further, from the known powder X-ray diffraction data (ICDD) of Sr ₂ Ta ₂ O ₇ (the known data used in the following examples and comparative examples are appropriately selected according to the composition that forms the main component of the crystal structure. that), the diffraction intensity of the peak of all faces (usually to the sum of the relative intensities) that the largest intensity as 100, was calculated p ₀ seeking the ratio of the diffraction intensity of the peak of the surface (111) (same as above) .. From these p and p ₀ , the lotgering factor f was calculated as the degree of orientation of the orientation plane (111) of the dielectric film. The results of these calculations were as follows.
p = 0.519
p ₀ = 0.028
f = 0.506

Variations in the inclination of the crystal axis of the alignment plane Next, the arc region including the spot of the orientation plane (111) of the two-dimensional X-ray diffraction image is set in the 2θ direction, in the dotted line region schematically shown in FIG. 5 (a). The integration was performed to obtain a one-dimensional profile, and the peak of the orientation plane (111) was fitted by a Gaussian function. The results are shown in FIG. 5 (b) (in the figure, the measurement data of the one-dimensional profile is shown by a solid line, and the data (including the background) fitted by the Gaussian function is shown by a dotted line). From this fitting, the half width (°) of the peak of the orientation plane (111) was measured and found to be 6.42 °.

Evaluation of electrical characteristics The electrical characteristics of the dielectric film of this example were evaluated. More specifically, a DC voltage of 3 V is applied between the upper electrode and the lower electrode of the capacitor manufactured as described above, and the relative permittivity (-), the dielectric loss (-) and the dielectric loss (-) are applied at a measurement frequency of 1 MHz. The current density (A / cm ² ) was measured. The results are shown in FIG. As can be understood from FIG. 6, the dielectric film of this embodiment exhibits a high relative permittivity exceeding 100 over 20 to 300 ° C., and the rate of change thereof is based on the relative permittivity at 20 ° C. It was less than 5%. Further, the dielectric film of this example showed a double-digit increase rate of the current density over 20 to 300 ° C., but showed a dielectric loss of less than 0.1 and functioned as a dielectric.

(Example 2)
The present embodiment relates to a dielectric film having a composition represented by (Sr _x La _1-x ) ₂ (Nb _x Ti _1-x ) ₂ O ₇ and a capacitor having such a dielectric film. Unless otherwise specified, the same description as in Example 1 applies (the same applies to the examples and comparative examples described in the present specification).

-Manufacturing procedure In step (a), the substrate was heated to 500 ° C. (that is, the substrate temperature was 500 ° C.), and RF sputtering used the target of the Sr ₂ Nb ₂ O ₇ raw material and the La ₂ Ti ₂ O ₇ raw material as the vapor deposition source. Using a target, the RF power ratio of the Sr ₂ Nb ₂ O ₇ raw material: La ₂ Ti ₂ O ₇ raw material was set to 50 W: 60 W, and the film was simultaneously vapor-deposited to (Sr _x La _1-x ) ₂ (Nb _x Ti _{1-). x} ) (Sr _x La _1-x ) ₂ (Nb _x Ti _1-x ) ₂ O _{7 in the same} manner as in Example 1 except that a precursor film having a composition represented by ₂ O ₇ was formed. A dielectric film having a composition represented by (1) was formed to obtain a capacitor (the PDA temperature was set to 900 ° C. as in Example 1). The thickness of the obtained dielectric film was about 200 nm.

-Analysis and Evaluation Composition The dielectric film of this example has a composition of (Sr _x La _1-x ) ₂ (Nb _x Ti _1-x ) ₂ O ₇ , and x = 5.0 in the formula. It has been found.

Main body and orientation plane of crystal structure A two-dimensional X-ray diffraction image of this dielectric film is shown in FIG. In the dielectric film of this example, it was identified that Sr ₂ Nb ₂ O ₇ mainly forms the crystal structure of the X-ray diffraction pattern. Further, in the dielectric film of this embodiment, a spot was observed near 2θ = 28 ° in the two-dimensional X-ray diffraction image shown in FIG. 7, and the X-ray diffraction pattern (one-dimensional profile) (not shown). Since the peak was present near 2θ = 28 °, it was found that the peak had the orientation plane of (150).

Orientation degree of orientation plane The orientation degree of the orientation plane (150) of this dielectric film was 0.68.

Variation of inclination of crystal axis of orientation plane The half width of the peak of the orientation plane (150) was 3.8 °.

Evaluation of Electrical Characteristics Figure 8 shows the results of evaluation of the electrical characteristics of the dielectric film of this example. As can be understood from FIG. 8, the dielectric film of this embodiment exhibits a high relative permittivity exceeding 100 over 20 to 150 ° C., and the rate of change thereof is based on the relative permittivity at 20 ° C. It was less than 5%. Further, the dielectric film of this example showed high insulating properties having a current density of 1 × 10 ^-7 A / cm ² or less and a dielectric loss of 0.05 or less. The dielectric film of this example had a large leakage current at a temperature exceeding 160 ° C., and its electrical characteristics were not evaluated.

(Comparative Examples 1 to 3)
This comparative example relates to a dielectric film having a composition represented by (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ and a capacitor having such a dielectric film.

-Manufacturing procedure Tables show the heating temperature of the substrate in step (a), the RF power ratio of the Sr ₂ Ta ₂ O ₇ raw material: La ₂ Ti ₂ O ₇ raw material, and the heat treatment temperature (PDA temperature) in step (b). A dielectric film having a composition represented by (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ in the same manner as in Example 1 except that they are different as shown in 2. Was formed to obtain a capacitor. The thickness of the obtained dielectric film is also shown in Table 2.

-Analysis and Evaluation Composition The dielectric film of this comparative example has a composition of (Sr _x La _1-x ) ₂ (Nb _x Ti _1-x ) ₂ O ₇ , and in the formula, comparative example 1 has x = 0. It was found that .66, Comparative Example 2 had x = 0.56, and Comparative Example 3 had x = 0.36.

Main body and orientation plane of crystal structure Two-dimensional X-ray diffraction images of the dielectric films of Comparative Examples 1 to 3 are shown in FIGS. 9 to 11, respectively. In the dielectric films of Comparative Examples 1 to 3, it was identified that Sr ₂ Ta ₂ O ₇ mainly forms the crystal structure. Further, in the dielectric film of Comparative Example 1, spots were observed near 2θ = 20 ° in the two-dimensional X-ray diffraction image shown in FIG. 9, and the X-ray diffraction pattern (one-dimensional profile) (not shown). Since the peak was present near 2θ = 20 °, it was found that the peak had the orientation plane of (041). In the dielectric film of Comparative Example 2, a plurality of peaks were observed in the X-ray diffraction pattern (one-dimensional profile) (not shown), and among them, the peak intensity was (for example, 2θ) on the (080) plane near 2θ = 26 °. It was larger (compared to the (0100) plane near = 33 °). However, since no spot was observed in the two-dimensional X-ray diffraction image shown in FIG. 10, the dielectric film of Comparative Example 2 does not have an orientation plane (in other words, the (080) plane is not an orientation plane). .. In the dielectric film of Comparative Example 3, a plurality of peaks were observed in the X-ray diffraction pattern (one-dimensional profile) (not shown), and the peak intensity was particularly large on the (111) plane near 2θ = 28 °. However, since no spot was observed in the two-dimensional X-ray diffraction image shown in FIG. 11, the dielectric film of Comparative Example 2 does not have an orientation plane (in other words, the (111) plane is not an orientation plane). .. Therefore, the dielectric film of this comparative example has orientation planes other than the planes of (h00), (0k0), (00l), (h0l) and (0kl) with respect to Sr ₂ Ta ₂ O ₇ which is the main component of the crystal structure. Does not have.

Orientation degree of orientation plane The orientation degree of the orientation plane (041) of the dielectric film of Comparative Example 1 was 0.66. Although the dielectric film of Comparative Example 2 was not an orientation plane, the degree of orientation of (080) was 0.065, and the degree of orientation of (010) was 0.22. The dielectric film of Comparative Example 3 was not an alignment plane, but the degree of orientation of (111) was 0.30.

Variation of Inclination of Crystal Axis of Orientation Plane The half width of the peak of the alignment plane (041) of the dielectric film of Comparative Example 1 was 3.1 °. The dielectric film of Comparative Example 2 was not an orientation plane, but the half width of the peak at (080) was 9.3 °. The dielectric film of Comparative Example 3 was not an orientation plane, but the half width of the peak of (111) was 15.9 °.

Evaluation of Electrical Characteristics The dielectric film of Comparative Example 1 exhibited a relative permittivity of about 45 and a dielectric loss of about 0.05 at room temperature (about 20 ° C.). The dielectric film of Comparative Example 2 exhibited a relative permittivity of about 30 and a dielectric loss of about 0.05 at room temperature (about 20 ° C.). The dielectric film of Comparative Example 3 exhibited a relative permittivity of about 600 and a dielectric loss of about 0.05 at room temperature (about 20 ° C.). For reference, Comparative Examples 1 to 3 were modified (each distance from the two vapor deposition sources was made different, etc.), and (Sr _x La _1-x ) ₂ (Ta _x Ti _1-x ) ₂ O ₇ . With respect to the dielectric film having the composition represented, the dielectric films and capacitors having different x in the formula were obtained, and the results of evaluating the electrical characteristics at room temperature (about 20 ° C.) are shown in FIG. 12 (in FIG. 12). indicating _{"xSr 2 Ta 2 O 7 - (} 1-x) La 2 Ti 2 O 7 " is a representation of the raw material _{base, (Sr x La 1-x} ) 2 (Ta x Ti 1-x) 2 O ₇ as synonymous). In each case, the relative permittivity was as low as less than 70.

(Comparative Example 4)
This comparative example relates to a dielectric film having a composition represented by Sr ₂ Ta ₂ O ₇ and a capacitor including such a dielectric film.

· In the manufacturing procedure step (a), the the RF sputtering, using a _Sr 2 _Ta 2 _{O 7} raw material target as evaporation _source, and an RF power of Sr 2 _Ta 2 _{O 7} raw material is deposited as _50W, Sr 2 _Ta 2 O _A capacitor was obtained by forming a dielectric film having a composition represented by Sr ₂ Ta ₂ O ₇ in the same manner as in Example 1 except that a precursor film having a composition represented by ₇ was formed. (Similar to Example 1, the substrate temperature was 500 ° C. and the PDA temperature was 900 ° C.). The thickness of the obtained dielectric film was about 200 nm.

-Analysis and evaluation composition The dielectric film of this comparative example has a composition of Sr ₂ Ta ₂ O ₇ , and the element of A is only Sr.

Main body and orientation plane of crystal structure The two-dimensional X-ray diffraction image and X-ray diffraction pattern of this dielectric film are shown in FIGS. 13 (a) and 13 (b), respectively (in FIG. 13 (b), "900 ° C." is shown. It is a pattern). In the dielectric film of this comparative example, Sr ₂ Ta ₂ O ₇ is the main component of the crystal structure. In the dielectric film of this comparative example, spots were observed near 2θ = 23 ° and 46 ° in the two-dimensional X-ray diffraction image shown in FIG. 13 (a), and at “900 ° C” in FIG. 13 (b). In the X-ray diffraction pattern (one-dimensional profile) shown in the above, peaks were present near 2θ = 23 ° and 46 °, and thus it was found that the X-ray diffraction patterns (110) and (200) had orientation planes. (However, it was found that the spots in (200) were slightly extended in a ring shape as compared with (110)). For reference, the X-ray diffraction pattern of the film obtained by modifying this comparative example is also shown in FIG. 13 (b), and “after film formation” indicates the precursor film of step (a). It is an X-ray diffraction pattern of the film after forming and before subjecting to step (b), and "700 ° C." and "800 ° C." set the heat treatment (PDA temperature) in step (b) to 700 ° C. It is an X-ray diffraction pattern of the obtained dielectric film. From FIG. 13B, it can be understood that a PDA temperature of 900 ° C. is required to bring about the orientation planes (110) and (200) by crystallization in this dielectric film.

Orientation degree of alignment plane The orientation degree of the orientation plane (110) of the dielectric film of this comparative example was 0.81, and the orientation degree of the orientation plane (200) was 0.08.

Variation of Inclination of Crystal Axis of Orientation Plane The half width of the peak of the alignment plane (110) of the dielectric film of Comparative Example 1 is 2.1 °, and the half width of the peak of the alignment plane (200) is 1.9 °. Met.

Evaluation of Electrical Characteristics FIG. 14 shows the results of evaluation of the electrical characteristics of the dielectric film of this comparative example. As can be seen from FIG. 14, the dielectric film of this comparative example exhibited a low relative permittivity of about 45 to 55 over 20 to 300 ° C.

(Comparative Example 5)
This comparative example relates to a dielectric film having a composition represented by Sr ₂ Nb ₂ O ₇ and a capacitor including such a dielectric film.

· In the manufacturing procedure step (a), the the RF sputtering, using a _Sr 2 _Nb 2 _{O 7} raw material target as evaporation _source, and an RF power of Sr 2 _Nb 2 _{O 7} raw material is deposited as _50W, Sr 2 _Nb 2 O A dielectric film having a composition represented by Sr ₂ Nb ₂ O ₇ was formed in the same manner as in Example 1 except that a precursor film having a composition represented by ₇ was formed to obtain a capacitor. (Similar to Example 1, the substrate temperature was 500 ° C. and the PDA temperature was 900 ° C.). The thickness of the obtained dielectric film was about 200 nm.

-Analysis and evaluation composition The dielectric film of this comparative example has a composition of Sr ₂ Nb ₂ O ₇ , and the element A is only Sr.

Main body and orientation plane of crystal structure The two-dimensional X-ray diffraction image and X-ray diffraction pattern of this dielectric film are shown in FIGS. 15 (a) and 15 (b), respectively (in FIG. 15 (b), "900 ° C." is shown. It is a pattern). In the dielectric film of this comparative example, Sr ₂ Nb ₂ O ₇ is the main component of the crystal structure. The dielectric film of this comparative example has a plurality of peaks in the X-ray diffraction pattern (one-dimensional profile) shown at “900 ° C.” in FIG. 15 (b), and among them, (131) near 2θ = 29 °. A relatively large peak was observed on the plane and the (150) plane near 2θ = 28 °. However, since no spots were observed in the two-dimensional X-ray diffraction image shown in FIG. 15 (a), the dielectric film of this comparative example has no orientation plane (in other words, the (131) plane and (in other words, the (131) plane) and ( 150) The plane is not an oriented plane). For reference, the X-ray diffraction pattern of the film obtained by modifying this comparative example is also shown in FIG. 15 (b), and “after film formation” indicates the precursor film of step (a). It is an X-ray diffraction pattern of the film after forming and before subjecting to step (b), and "700 ° C." and "800 ° C." set the heat treatment (PDA temperature) in step (b) to 700 ° C. and 800 ° C., respectively. It is an X-ray diffraction pattern of the obtained dielectric film.

Orientation degree of orientation plane Although the dielectric film of this comparative example is not an orientation plane, the orientation degree of (131) was 0.52 and the orientation degree of (150) was 0.30.

Variation of inclination of crystal axis of alignment plane Although the dielectric film of this comparative example is not an orientation plane, the half width of the peak of (131) is 21.4 ° and the half width of the peak of (150) is 20. It was 8.8 °.

Evaluation of Electrical Characteristics Figure 16 shows the results of evaluation of the electrical characteristics of the dielectric film of this comparative example. As can be understood from FIG. 16, the dielectric film of this comparative example exhibited a low relative permittivity of about 40 to 60 over 20 to 300 ° C.

(Comparative Example 6)
This comparative example relates to a dielectric film having a composition represented by La ₂ Ti ₂ O ₇ and a capacitor including such a dielectric film.

· In the manufacturing procedure step (a), the the RF sputtering, using _La 2 _Ti 2 _{O 7} raw material target as evaporation _source, and the La 2 _Ti 2 _{O 7} raw RF power deposited as _50W, La 2 _Ti 2 O _A capacitor was obtained by forming a dielectric film having a composition represented by La ₂ Ti ₂ O ₇ in the same manner as in Example 1 except that a precursor film having a composition represented by ₇ was formed. (Similar to Example 1, the substrate temperature was 500 ° C. and the PDA temperature was 900 ° C.). The thickness of the obtained dielectric film was about 80 nm.

-Analysis and evaluation composition The dielectric film of this comparative example has a composition of La ₂ Ti ₂ O ₇ , and the element A is only La.

Main body and orientation plane of crystal structure The two-dimensional X-ray diffraction image and X-ray diffraction pattern of this dielectric film are shown in FIGS. 17 (a) and 17 (b), respectively (in FIG. 17 (b), “900 ° C.” is shown. It is a pattern). In the dielectric film of this comparative example, La ₂ Ti ₂ O ₇ mainly forms the crystal structure. The dielectric film of this comparative example has a plurality of peaks in the X-ray diffraction pattern (one-dimensional profile) shown at “900 ° C.” in FIG. 17 (b), and among them, (400) near 2θ = 28 °. A relatively large peak was observed on the surface. However, since no spots were observed in the two-dimensional X-ray diffraction image shown in FIG. 17A, the dielectric film of this comparative example does not have an orientation plane (in other words, the (400) plane is orientation. Not a face). For reference, the X-ray diffraction pattern of the film obtained by modifying this comparative example is also shown in FIG. 17 (b), and “after film formation” indicates the precursor film of step (a). It is an X-ray diffraction pattern of the film after forming and before subjecting to step (b), and "700 ° C." and "800 ° C." set the heat treatment (PDA temperature) in step (b) to 700 ° C. It is an X-ray diffraction pattern of the obtained dielectric film.

Orientation degree of orientation plane Although the dielectric film of this comparative example is not an orientation plane, the orientation degree of (400) was 0.534.

Variations in the inclination of the crystal axis of the alignment plane Although the dielectric film of this comparative example is not the orientation plane, the half width of the peak at (400) was 23.8 °.

Evaluation of Electrical Characteristics When the electrical characteristics of the dielectric film of this comparative example were evaluated, the relative permittivity of about 43, the dielectric loss of about 0.05, and about 3 × 10 ^-7 A / at room temperature (about 20 ° C.). The current density of cm ² is shown. In a system in which the element A is only La as in this comparative example, the leakage current tends to be large, and in the dielectric film of this comparative example, the leakage current exceeds 1 mA at 50 ° C. or higher, and the electrical characteristics are evaluated. I couldn't.

(Comparative Example 7)
This comparative example relates to a dielectric film having a composition represented by La ₂ Zr ₂ O ₇ and a capacitor including such a dielectric film.

· In the manufacturing procedure step (a), the the RF sputtering, using a _La 2 _Zr 2 _{O 7} raw material target as evaporation _source, and the La 2 _Zr 2 _{O 7} raw RF power deposited as _50W, La 2 _Zr 2 O _A capacitor was obtained by forming a dielectric film having a composition represented by La ₂ Zr ₂ O ₇ in the same manner as in Example 1 except that a precursor film having a composition represented by ₇ was formed. (Similar to Example 1, the substrate temperature was 500 ° C. and the PDA temperature was 900 ° C.). The thickness of the obtained dielectric film was about 60 nm.

-Analysis and evaluation composition The dielectric film of this comparative example has a composition of La ₂ Zr ₂ O ₇ , and the element A is only La.

Main body and orientation plane of crystal structure The two-dimensional X-ray diffraction image and X-ray diffraction pattern of this dielectric film are shown in FIGS. 18 (a) and 18 (b), respectively (in FIG. 18 (b), "900 ° C." is shown. It is a pattern). In the dielectric film of this comparative example, La ₂ Zr ₂ O ₇ mainly forms the crystal structure. The dielectric film of this comparative example has a plurality of peaks in the X-ray diffraction pattern (one-dimensional profile) shown at “900 ° C.” in FIG. 18 (b), and among them, (222) near 2θ = 29 °. A relatively large peak was observed on the plane and the (444) plane near 2θ = 59 °. However, in the two-dimensional X-ray diffraction image shown in FIG. 17A, spots were observed near 2θ = 29 °, and no spots were observed elsewhere. Therefore, the dielectric film of this comparative example was ( It was found to have an orientation plane of 222) (in other words, the (444) plane is not an orientation plane). For reference, the X-ray diffraction pattern of the film obtained by modifying this comparative example is also shown in FIG. 18 (b), and “after film formation” indicates the precursor film of step (a). It is an X-ray diffraction pattern of the film after forming and before subjecting to step (b), and "700 ° C." and "800 ° C." set the heat treatment (PDA temperature) in step (b) to 700 ° C. It is an X-ray diffraction pattern of the obtained dielectric film.

Orientation degree of orientation plane In the dielectric film of this comparative example, the orientation degree of the orientation plane (222) was 0.97.

Variations in the inclination of the crystal axis of the oriented plane In the dielectric film of this comparative example, the half width of the peak of the oriented plane (222) was 4.3 °.

Evaluation of electrical characteristics When the electrical characteristics of the dielectric film of this comparative example were evaluated, at room temperature (about 20 ° C), a relative permittivity of about 45, a dielectric loss of about 0.1, and about 2 × 10 ^-2 A / The current density of cm ² is shown. In a system in which the element A is only La as in this comparative example, the leakage current tends to be large, and in the dielectric film of this comparative example, the leakage current exceeds 1 mA at 50 ° C. or higher, and the electrical characteristics are evaluated. I couldn't.

(Comparative Example 8)
This comparative example relates to a dielectric film having a composition represented by Sr ₂ (Ta _x Nb _1-x ) ₂ O ₇ and a capacitor including such a dielectric film.

-Manufacturing procedure In step (a), RF sputtering uses a target of Sr ₂ Ta ₂ O ₇ raw material and a target of Sr ₂ Nb ₂ O ₇ raw material as a vapor deposition source, and Sr ₂ Ta ₂ O ₇ raw material: Sr ₂ Nb. The RF power ratio of the ₂ O ₇ raw material is 50 W: 50 W, and the opening area is alternately vapor-deposited via a controllable shutter mechanism to obtain a composition represented by Sr ₂ (Ta _x Nb _1-x ) ₂ O _7. A capacitor was obtained by forming a dielectric film having a composition represented by Sr ₂ (Ta _x Nb _1-x ) ₂ O ₇ in the same manner as in Example 1 except that the precursor film having the precursor film was formed. (Similar to Example 1, the substrate temperature was 500 ° C. and the PDA temperature was 900 ° C.). The thickness of the obtained dielectric film was about 70 nm.

-Analysis and evaluation composition The dielectric film of this comparative example has a composition represented by Sr ₂ (Ta _x Nb _1-x ) ₂ O ₇ , and x = in the formula depending on the position on the dielectric film. It turned out to be 0, 0.2, 0.4, 0.6, 0.8 and 1.0. By alternately vapor-depositing from two thin-film deposition sources while controlling the opening area of the shutter, the composition can be inclined in the dielectric film, which is generally close to the Sr ₂ Ta ₂ O ₇ raw material. The region became Sr ₂ Ta ₂ O ₇ rich, and the region close to the Sr ₂ Nb ₂ O ₇ raw material became Sr ₂ Nb ₂ O ₇ rich.

The X-ray diffraction pattern (one-dimensional profile) of each region in which x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0 in this dielectric film is shown in FIG. 19 (FIG. 19). shown in 19 _{"xSr 2 Ta 2 O 7 - (} 1-x) Sr 2 Nb 2 O 7 " is a representation of the raw material _base, synonymous with _{Sr 2 (Ta x Nb 1-} x) 2 O 7 Is). When x = 0, there was no orientation plane as in the dielectric film of Comparative Example 5. When x = 1.0, the dielectric film of Comparative Example 4 had an orientation plane (110). In any case of x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0, the relative permittivity at room temperature (25 ° C.) is 60 or less, which is a high relative permittivity. Was not obtained.

(Comparative Example 9)
This comparative example relates to a dielectric film having a composition represented by La ₂ (Zr _x Ti _1-x ) ₂ O ₇ and a capacitor including such a dielectric film.

-Manufacturing procedure In step (a), the substrate was heated to 550 ° C (that is, the substrate temperature was 550 ° C), and RF sputtering was performed as a vapor deposition source for the target of the La ₂ Zr ₂ O ₇ raw material and the La ₂ Ti ₂ O ₇ raw material. using a _target, La 2 _Zr 2 _{O 7} raw _material: La 2 _Ti 2 _{O 7} raw RF power ratio of the 50 W: as 50 W, by depositing alternately via a controllable shutter mechanism opening area, _La 2 ( Zr _x Ti _1-x ) La ₂ (Zr _x Ti _1-x ) ₂ O ₇ in the same manner as in Example 1 except that a precursor film having a composition represented by ₂ O ₇ was formed. A dielectric film having the composition to be obtained was formed to obtain a capacitor (the PDA temperature was set to 900 ° C. as in Example 1). The thickness of the obtained dielectric film was about 70 nm.

-Analysis and Evaluation Composition The dielectric film of this comparative example has a composition represented by La ₂ (Zr _x Ti _1-x ) ₂ O ₇ , and x = in the formula depending on the position on the dielectric film. It turned out to be 0, 0.2, 0.4, 0.6, 0.8 and 1.0. By alternately vapor-depositing from two thin-film deposition sources while controlling the opening area of the shutter, the composition gradient can be generated in the dielectric film, and is generally close to the La ₂ Zr ₂ O ₇ raw material. The region became La ₂ Zr ₂ O ₇ rich, and the region close to the La ₂ Ti ₂ O ₇ raw material became La ₂ Ti ₂ O ₇ rich.

The X-ray diffraction pattern (one-dimensional profile) of each region in which x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0 in this dielectric film is shown in FIG. 20 (FIG. 20). shown in 20 _{"xLa 2 Zr 2 O 7 - (} 1-x) La 2 Ti 2 O 7 " is a representation of the raw material _{base, La 2 (Zr x Ti 1} -x) 2 O 7 as defined Is). When x = 0, there was no orientation plane as in the dielectric film of Comparative Example 6. When x = 1.0, the dielectric film of Comparative Example 7 had an orientation plane (222). (Note that Comparative Examples 6 and 7 have a substrate temperature of 500 ° C., unlike this Comparative Example.) X = 0, 0.2, 0.4, 0.6, 0.8 and 1 In any case of .0, the relative permittivity at room temperature (25 ° C.) was 50 or less, and a high relative permittivity could not be obtained. Further, in any of these cases, the leakage current exceeded 1 mA at 50 ° C. or higher, and the electrical characteristics could not be evaluated.

The dielectric film of the present invention is suitably used as a dielectric film in a capacitor (particularly a thin film capacitor), and such a capacitor can be used for various electronic components, but the dielectric film of the present invention is not limited to such applications. ..

The present application claims priority based on Japanese Patent Application No. 2019-105680 filed in Japan on June 5, 2019, and all the contents thereof are incorporated herein by reference.

1 Substrate 3 Electrodes (lower electrode)
5 Dielectric film 7 Electrode (upper electrode)
10 Capacitor

Claims (17)

1. A dielectric film having a pyrochlore-type or layered perovskite-type crystal structure.
   General formula A ₂ B ₂ O ₇ (In the formula, A is Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb. Two or more elements selected from the group consisting of and Lu, each containing A ¹ and A ² different from each other, where B is from Ti, Zr, Hf, V, Nb and Ta. and one or more elements selected from the group consisting having a composition represented by the among containing B ¹ as one element),
   Of all the combinations of A ₂ B ₂ O ₇ obtained stoichiometrically by selecting one of each of the elements A and B existing in the dielectric film, the main component of the crystal structure of the dielectric film. With respect to A ¹ ₂ B ¹ ₂ O ₇ forming the above, in addition to the faces (h00), (0k0), (00l), (h0l) and (0kl) (h, k and l are integers excluding 0). A dielectric film having at least one orientation plane.
2. The dielectric film according to claim 1, wherein the at least one orientation plane is a plane other than the plane (hk0) with respect to the A ¹ ₂ B ¹ ₂ O ₇ .
3. The dielectric film according to claim 1 or 2, wherein the at least one orientation plane has an orientation degree of 0.5 or more and 1 or less.
4. The dielectric film according to any one of claims 1 to 3, wherein the variation in the inclination of the crystal axis of at least one orientation plane is 10 ° or less.
5. Any of claims 1 to 4, wherein the content ratio of A ¹ is less than 50 atomic% and the content ratio of A ² is 50 atomic% or more with respect to the total amount of A in the dielectric film. Dielectric film described in Crab.
6. The dielectric film according to any one of claims 1 to 5, wherein A ¹ and A ² have different valences from each other.
7. The dielectric film according to any one of claims 1 to 6, wherein A ¹ is Sr and A ² is La.
8. The dielectric according to any one of claims 1 to 7, which has a thickness of 3 nm or more and 1 μm or less.
9. A capacitor including an electrode and the dielectric film according to any one of claims 1 to 8 arranged on the electrode.
10. The capacitor according to claim 9, wherein the surface of the electrode in contact with the dielectric film is the surface of (111) or (001).
11. A method for producing a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure.
    (A) On the surface of the substrate heated to a temperature of 350 to 600 ° C., the general formula A ₂ B ₂ O ₇ (in the formula, A is Mg, Ca, Sr, Ba, La, Ce, Pr, Nd, Pm. , Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, two or more elements selected from the group, each of which is different from each other, A ¹ and A ^2. B is one or more elements selected from the group consisting of Ti, Zr, Hf, V, Nb and Ta, and B ¹ is included as one of the elements). The precursor film to have is formed by vapor phase deposition, and (b) the substrate on which the precursor film is formed is heat-treated at a temperature of 850 to 1050 ° C. in an atmosphere containing oxygen to form the precursor film. A production method comprising obtaining a dielectric film having a pyrochlore-type or layered perovskite-type crystal structure and having the above composition from the above.
12. The A ₂ B ₂ O ₇ is A ¹ ₂ B ¹ ₂ O ₇ and A ² ₂ B ² ₂ O ₇ (A ¹ , A ² and B ^{1 in the} formula are as described above, and B ² is Ti. , Zr, Hf, V, Nb and Ta, which are the same or different elements as B ¹ ), and the A ¹ ₂ B ¹ ₂ O ₇ is the A ² ₂ B ² ₂ having a lower crystallization temperature than O _7, method for producing a dielectric film according to claim 11.
13. In (a), the gas phase deposition uses a first raw material having the composition of A ¹ ₂ B ¹ ₂ O ₇ and a second raw material having the composition of A ² ₂ B ² ₂ O _7. 12. The method for producing a dielectric film according to claim 12.
14. Claimed that the gas phase deposition is carried out under the condition that the growth rate of A ² ₂ B ² ₂ O ₇ from the second raw material is larger than the growth rate of A ¹ ₂ B ¹ ₂ O ₇ from the first raw material. Item 13. The method for producing a dielectric film according to Item 13.
15. The method for producing a dielectric film according to claim 14, wherein the vapor phase deposition is carried out under a condition that the output applied to the second raw material is larger than the output applied to the first raw material by high frequency sputtering.
16. The method for producing a dielectric film according to any one of claims 11 to 15, wherein the heat treatment is carried out in a gas atmosphere containing oxygen in the above (b).
17. The 11th to 16th claims, wherein the substrate has a conductive member in advance on the surface thereof, and the precursor film is formed on the conductive member of the substrate by vapor deposition. The method for producing a dielectric film according to any one.

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