JPH11273989A - Dielectric thin film and ceramic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric thin film in which lead is not contained, a dielectric constant is high, a loss is low, the temperature change rate of an electrostatic capacity is small, and a relative dielectric constant is large even in a high frequency region, and provide also a ceramic capacitor. SOLUTION: In a dielectric thin film having thickness of 2 μm or less comprising a tungsten bronze type crystal phase containing K, Sr, and Nb as metallic elements, when a composition formula by the mol rate of a metallic element oxide is shown or (1-y)K(Sr1-x Bax )2 Nb5 O15 .5y/2(Sr1-x Bax )Nb2 O6 , (x) and (y) satisfy a relational expression of y=0 and 0<=x<=0.20, or a relational expression 0<y<=0.10 and 0.05<=x<=0.25.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric thin film and a ceramic capacitor using the dielectric thin film.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and thinner, there has been a demand for smaller and thinner electronic components. In particular, miniaturization and thinning of capacitors, which are passive components, are essential. Electronic devices using high-speed digital circuits, such as computers, are in the trend of higher frequencies, and the operating frequency band from several tens of MHz to several hundreds of MHz is becoming important. Along with this, it has become essential that passive components such as capacitors also exhibit excellent characteristics with respect to high-frequency or high-speed digital pulses.

BaTiO ₃ , which is a Ti compound having a perovskite structure, is known to be useful as a capacitor material because it has a large relative dielectric constant and good temperature characteristics. In addition, a composite perovskite oxide composed of two or more metals, particularly Pb (Mg _1/3 Nb _2/3 ) O ₃ (hereinafter, also referred to as PMN) has a large relative dielectric constant at room temperature, and therefore, a capacitor material. It is known to be useful as

In recent years, it has been attempted to reduce the thickness of a high dielectric constant material such as BaTiO ₃ or PMN and apply it to a thin film capacitor. However, in the conventional solid phase sintering method, the film thickness is at most 10 μm.
It was about. In the case of PMN, a stable pyrochlore phase is easily formed at a low temperature similarly to a sintered body obtained by a solid phase sintering method even in a thin film, and it is difficult to obtain a film composed of a single perovskite single phase, which is unsuitable as a capacitor material. Often. In particular, when the film is made thinner, it is said that there is a problem that a pyrochlore phase is easily generated due to lattice mismatch with the lower electrode and a difference in chemical bond (see, for example, JP-A-6-57437). It was difficult to obtain a perovskite single-phase PMN thin film having few phases.

[0005] As a method of solving the problem of the formation of the pyrochlore phase, a PMN thin film produced by a sol-gel method is subjected to a rapid heating calcination (see JP-A-2-177521) or a seeding method (see JP-A-6-177521). Various methods have been proposed, and a PMN thin film close to a perovskite single phase has been obtained.

In recent years, lead-containing high-capacity capacitors have been demanded because of the large influence of lead compounds on the environment. For example, in recent years, a functional material obtained by thinning a material having a tungsten bronze structure has been reported (Japan).
ese Journal of Applied Ph
ysics, Vol. 36, pp. 5930-593
4, (1997). ).

Conventionally, it has been considered that a tungsten bronze structure has a large anisotropy and it is difficult to produce a dense film. ) Discloses that a dense film was obtained by forming an alignment film on a Pt / MgO substrate;
K (Sr _0.75 Ba _0.25 ) ₂ Nb ₅ O ₁₅
It is disclosed that a high dielectric constant film can be obtained by thinning the film on a Pt / MgO substrate.

[0008]

However, BaTiO _3, which is a typical capacitor material, shows a large relative dielectric constant of about 3000 at a low frequency of about 1 KHz, and is an excellent material as a capacitor material. Due to the large dispersion, the relative dielectric constant in the high frequency region is greatly reduced, and it has been considered that the material cannot be used as a high dielectric constant material in the high frequency region (see JP-A-6-77083).

Further, BaTiO ₃ greatly differs in physical properties depending on the particle size, and exhibits a high dielectric constant at a particle size of about 1 μm. However, when the particle size is smaller than 1 μm, the relative dielectric constant monotonously decreases with the particle size.
Since the particle size of the thin film is smaller than 1 μm, there is a problem that a thin film having a relative dielectric constant as high as that of the bulk body cannot be obtained.

Further, in order to increase the particle size, high-temperature baking exceeding 1000 ° C. is necessary, and a reaction with the substrate and the electrode occurs, and a low dielectric constant phase is generated at the interface.
There is a problem that a high dielectric constant cannot be obtained even if the particle size is increased.

[0011] On the other hand, PMN is an excellent capacitor material that exhibits a large relative dielectric constant even in a thin film, but has a problem that it has a large environmental impact because it is mainly composed of lead.

Further, K (Sr _0.75
The Ba _0.25 ) ₂ Nb ₅ O ₁₅ material has a dielectric constant at a measurement frequency of 10 KHz at room temperature of about 2,000 and shows a high dielectric constant, but has a problem that the dielectric loss is as large as about 12% under the above measurement conditions. . Further, in this material, since the peak temperature of the relative dielectric constant is around 70 ° C., a thin film capacitor material having a large temperature change rate and excellent temperature characteristics has been desired.

[0013]

According to the present invention, there is provided a dielectric thin film comprising:
A dielectric thin film made of a tungsten bronze type crystal phase containing K, Sr and Nb as metal elements and having a thickness of 2 μm or less, wherein the composition formula based on the molar ratio of the metal element oxide is (1-y) K (Sr _{1 -x Ba x) 2 Nb 5 O} 15 · 5y /
2 (Sr _1-x Ba _x ) Nb ₂ O ₆ ,
y satisfies the relational expression of y = 0 and 0 ≦ x ≦ 0.20, or the relational expression of 0 <y ≦ 0.10 and 0.05 ≦ x ≦ 0.25.

Here, it is preferable that the [001] axis is mainly composed of a tungsten bronze type crystal phase oriented in the thickness direction. The average crystal grain size is 0.05 to 0.15 μm
It is desirable that Furthermore, a measurement frequency of 1 kHz
It is desirable that the relative permittivity at (room temperature) is 1000 or more and the relative permittivity at a measurement frequency of 100 MHz (room temperature) is 1000 or more.

A ceramic capacitor according to the present invention comprises a pair of electrodes formed on both surfaces of the dielectric thin film so as to face each other. Here, the electrode is desirably Pt or Au with the [111] axis oriented in the thickness direction.

[0016]

According to the dielectric thin film of the present invention, K (Sr _1-x B
a _x ) ₂ Nb ₅ O ₁₅ (hereinafter, may be referred to as KSBN).
By satisfying the relational expression of 0.20, a dielectric thin film having a high dielectric constant, low loss, and excellent temperature characteristics can be obtained.

Further, (1-y) K (Sr _1-x Ba _x ) ₂
In _{Nb 5 O 15 · 5y / 2} (Sr 1-x Ba x) composition formula by molar ratio represented by _{Nb 2 O 6, 0 <y} ≦ 0.1
By satisfying the relational expression of 0 and 0.05 ≦ x ≦ 0.25, KS having a relative dielectric constant peak at a temperature higher than room temperature
By dissolving (Sr _1-x Ba _x ) Nb ₂ O ₆ (hereinafter also referred to as SBN) having a relative permittivity peak at a lower temperature than KSBN in BN, the relative permittivity itself is slightly lowered. However, the temperature at which the relative dielectric constant of KSBN becomes maximum can be controlled to around room temperature, the relative dielectric constant at room temperature can be improved, and the temperature characteristics of the relative dielectric constant and the DC bias characteristics can be improved.

Further, by forming the thin film having a thickness of 2 μm or less, the average crystal grain size of the tungsten bronze type composite oxide is reduced to the order of submicron, and the paraelectric property becomes more dominant. Temperature characteristics of capacitance and D
C bias characteristics can be improved. Also, 10
Even at a high frequency such as 0 MHz, since the macro spontaneous polarization, which is the origin of ferroelectricity, is reduced by thinning, the frequency dispersion of the dielectric constant caused by the spontaneous polarization is small, and a large relative permittivity is exhibited even at a high frequency. For example, the relative dielectric constant at a measurement frequency of 1 kHz (room temperature) is 1000 or more, and the relative dielectric constant at a measurement frequency of 100 MHz (room temperature) is 1000 or more.

Furthermore, the relative dielectric constant can be drastically improved by mainly using a tungsten bronze type crystal phase whose [001] axis is oriented in the thickness direction (perpendicular to the substrate). On the electrode whose [111] axis is oriented in the thickness direction,
By precipitating the tungsten bronze type crystal phase, the tungsten bronze type crystal phase whose [001] axis is oriented in the thickness direction becomes the main component.

Further, the average crystal grain size is set to 0.05 to
By setting the thickness to 0.15 μm, it is possible to reduce the thickness to submicron or less.

In the ceramic capacitor of the present invention, for example, platinum (Pt) or gold (A) having a thickness of 0.05 μm or more is formed on both surfaces of the dielectric thin film having the excellent characteristics as described above.
u), by forming a pair of electrodes, which are palladium (Pd) thin films, facing each other, a thin film capacitor excellent in high dielectric constant even at high frequencies can be obtained.

Further, the electrode is made of Pt or Au whose [111] axis is oriented in the thickness direction (perpendicular to the substrate).
By doing so, a tungsten bronze-type crystal phase in which the [001] axis is oriented in the direction perpendicular to the substrate is easily deposited, and the relative dielectric constant of the dielectric thin film can be improved, thereby improving the capacitance.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The dielectric thin film of the present invention has a thickness of 2 μm.
m or less. Here, the reason why the dielectric thin film having a film thickness of 2 μm or less is that when the thickness is larger than this, the number of steps increases, and when a capacitor is formed, the capacitance decreases. The thickness of the dielectric thin film is easy to manufacture,
The thickness is preferably 1 μm or less from the viewpoint of film quality deterioration, and particularly preferably 0.3 to 1 μm in consideration of the insulating property of the film.
Further, the composition formula by molar ratio (1-y) K (Sr 1-x Ba x) 2 Nb 5 O 15 · 5y
/ 2 (Sr _1-x Ba _x ) Nb ₂ O ₆ , x, y
Satisfy the relational expression of y = 0 and 0 ≦ x ≦ 0.20, or the relational expression of 0 <y ≦ 0.10 and 0.05 ≦ x ≦ 0.25.

Here, in the above composition formula, when y = 0, that is, when K (Sr _1-x Ba _x ) ₂ Nb ₅ O ₁₅ , 0 ≦
The reason for setting x ≦ 0.20 is that when the substitution amount x of Ba is larger than 0.2, the dielectric loss of the obtained dielectric thin film increases, and the temperature change rate of the relative dielectric constant increases. It is. When y = 0, x preferably satisfies 0.05 ≦ x ≦ 0.15.

When 0 <y ≦ 0.10.
The reason for satisfying x ≦ 0.25 is that when y is larger than 0.10, a phase having a SrNb ₂ O ₆ structure having a low dielectric constant structure is generated, and the relative dielectric constant is reduced. is there. To improve the relative dielectric constant, the range of y is 0.05 ≦ y ≦
0.10 is desirable.

The reason for satisfying 0.05 ≦ x ≦ 0.25 is that when x is larger than 0.25, the relative dielectric constant at room temperature rapidly decreases and the film becomes porous. It is. On the other hand, when x is smaller than 0.05, a phase having a SrNb ₂ O ₆ structure, which is a low dielectric constant phase, is generated and the dielectric constant becomes low. To improve the relative dielectric constant, the range of x is desirably 0.15 ≦ x ≦ 0.25.

In the dielectric thin film of the present invention, it is preferable that the [001] axis is mainly composed of a tungsten bronze type crystal phase oriented in the thickness direction. Here, a tungsten bronze-type crystal phase whose [001] axis is oriented in the thickness direction is mainly used, for example, when the X-ray diffraction measurement is performed with reference to a reciprocal lattice of a sapphire substrate, and the (0)
02) When the rocking curve is obtained by rotating only the crystal at the peak, the half width is 10 degrees or less, especially 5
It means the case where the mosaic degree is less than or equal to the degree. The relative dielectric constant can be greatly improved by mainly using the tungsten bronze type crystal phase in which the [001] axis is oriented in the thickness direction in the thickness direction.

The average crystal grain size is 0.05 to 0.15.
By setting it to μm, thinning can be further promoted. The tungsten bronze-type crystal particles have a substantially columnar shape, and the average crystal particle size of the dielectric thin film is a particle size calculated by intercepting the thin film surface.

The dielectric thin film of the present invention has a measurement frequency of 1 kHz.
The dielectric constant at z (room temperature) is 1000 or more, and the dielectric constant at a measurement frequency of 100 MHz (room temperature) is 1000 or more.

Further, in the dielectric thin film of the present invention, the composition formula based on the molar ratio is (1-y) K (Sr _{1 -x} Ba _x ) ₂ Nb.
_{5 O 15 · 5y / 2 (} Sr 1-x Ba x) Nb 2 O 6, in other _{words, K 1-y (Sr 1} -x Ba x) 2 + y / 2 Nb 5 O 15
And tungsten bronze type crystal particles represented by

Further, the ceramic capacitor of the present invention
An electrode is formed on a substrate, the above-described dielectric thin film is formed on the electrode, and the electrode is formed on the dielectric thin film. It is needless to say that a laminated ceramic capacitor in which dielectric thin films and electrodes are alternately laminated may be used.

The thickness of the capacitor electrode is 0.05
[111] oriented platinum (Pt), gold (A
u), palladium (Pd) thin film and the like, and among these, a platinum (Pt) and gold (Au) thin film whose [111] axis is oriented in a direction perpendicular to the substrate (thickness direction) is optimal. This is because Pt and Au have low reactivity with the dielectric thin film and are not easily oxidized, so that a low dielectric constant phase is hardly formed at the interface with the film.

The reason why the Pt and Au having the [111] axis oriented in the direction perpendicular to the substrate is optimal is that these electrodes can be realized even if the underlying substrate is glass, and the crystallinity of the substrate is not selected. Excellent in point. Also, on Pt or Au whose [111] axis is oriented perpendicular to the substrate,
This is because the [001] axis of the tungsten bronze type crystal phase of the KSBN thin film is easily oriented in the thickness direction (c-axis orientation). Such orientation maximizes the dielectric properties of KSBN.

The thickness of the electrode is desirably 0.05 μm or more. If the thickness is less than 0.05 μm, the equivalent series resistance becomes large and the flow of current in the high frequency region is hindered. [111] The Pt thin film in which the axis is oriented perpendicular to the substrate is an oriented or single-crystal platinum (Pt) thin film, and the oriented Pt thin film is one in which the crystal axis is one of the crystal axes. The film is aligned in a direction approximately perpendicular to the film surface, and a single-crystal Pt thin film is a film in which all three crystal axes are aligned. Such an electrode whose [111] axis is oriented perpendicular to the substrate has a substrate temperature of 450 when the electrode is formed by physical vapor deposition such as sputter deposition or laser vapor deposition.
C. or higher. Of these, sputter deposition with a substrate temperature of 450 ° C. or higher is desirable.

The substrate on which the electrodes are deposited may be alumina, sapphire, MgO single crystal, SrTiO ₃ single crystal, titanium-coated silicon, or copper (Cu), nickel (Ni), titanium (Ti), tin (Sn). A stainless steel (SUS) thin film or thin plate is desirable. In particular, alumina and sapphire are desirable in that they have low reactivity with the thin film, are inexpensive, have high hardness, and have crystallinity of the metal thin film.

The thin-film capacitor of the present invention can
The lower electrode is formed by depositing t, Au, Pd, or the like on the substrate by a method such as sputtering, vapor deposition, or gravure printing, and the dielectric thin film is formed on the surface of the lower electrode by the above method. Then, an upper electrode is formed on the surface of the dielectric thin film in the same manner as the lower electrode. Also,
A multilayer capacitor is obtained by alternately stacking dielectric thin films and electrodes.

The dielectric thin film of the present invention is produced, for example, as follows. First, K, Sr,
A precursor solution in which the organometallic compounds of Ba and Nb are uniformly dissolved is prepared.

At least one Sr compound selected from organic acid salts, inorganic salts and alkoxides of Sr and Ba;
Ba compound was prepared by acetic acid (CH ₃ COOH) or R ₁ OH or R ₂ OC ₂ H ₄ at a molar ratio of Sr: Ba = 1-x: x.
OH and R ₃ COOH (R ₁ , R ₂ , R ₃ : an alkyl group having 1 or more carbon atoms) are mixed in a solvent. After mixing, a predetermined operation is performed to synthesize a stable Sr—Ba solution even in the presence of another nucleophilic organometallic compound.

Next, at least one K compound selected from organic acid salts, inorganic salts and alkoxides of K is converted to acetic acid (C
H ₃ COOH) or R ₁ OH, R ₂ OC ₂ H ₄ O
H and R ₃ COOH (R ₁ , R ₂ , R ₃ : an alkyl group having 1 or more carbon atoms) are mixed in a solvent.

Next, one kind of Nb compound selected from Nb organic acid salts, alkoxides and the like is converted to acetic acid (CH ₃ COO).
H) or R ₁ OH, R ₂ OC ₂ H ₄ OH, R ₃ CO
OH (R ₁ , R ₂ , R ₃ : alkyl group having 1 or more carbon atoms)
To prepare a Nb solution.

The K solution and the Sr—Ba solution thus prepared were combined with K: S
Mix at a molar ratio of r-Ba = 1-y: 2 + y / 2, add a chelating agent such as acetylacetone to the K-Sr-Ba solution in an amount of 0 to 3 times the metal amount, and mix.

The prepared K-Sr-Ba solution and Nb solution are mixed at a molar ratio of K-Sr-Ba: Nb = 3-y / 2: 5 to obtain a K-Sr-Ba-Nb precursor solution. The prepared coating solution is formed on a substrate by a method such as spin coating, dip coating, or spraying.

After the film formation, at a temperature of 300 to 600.degree.
Heat treatment is performed for up to 5 minutes to burn the organic substances remaining in the film to form a gel film. Then, at 700-1000 ° C, 1-3
A crystallization heat treatment is performed for 0 minutes. The thickness of each film is preferably 0.2 μm or less.

The film formation and heat treatment are repeated until the film thickness reaches a predetermined value. Finally, baking is performed at 700 ° C. to 1000 ° C. for 0 to 1 hour. The thickness of the obtained dielectric thin film is 2 μm or less. If the thickness is larger than this, the number of steps increases, and if a capacitor is formed, the capacitance decreases.

[0045]

EXAMPLE Sr acetate 0.5 hydrate and Ba acetate 0.8 were added.
The mixture was weighed at a molar ratio of 0: 0.20 and refluxed in acetic acid (1.
(1 hour at 18 ° C.) to synthesize an Sr—Ba solution having a concentration of 0.5 M (mol / l). Next, K ethoxide was mixed with acetic acid at room temperature to prepare a 0.5 M K solution. Next, Nb ethoxide was dissolved in acetic acid at room temperature to prepare a 0.5 M Nb solution.

The K solution and the Sr-Ba solution were combined with K: Sr-
After mixing at a ratio of Ba = 1: 2, acetylacetone was added to the K-Sr-Ba solution in an amount of 1 times the total amount of metals, followed by stirring at room temperature for 10 minutes to stabilize.

The K-Sr-Ba solution and the Nb solution are mixed with K-Sr
-Ba: Nb = 3: 5, and the mixture was stirred at room temperature for 10 minutes to obtain 0.5M K (Sr _0.80
A Ba _0.20 ) ₂ Nb ₅ O ₁₅ precursor solution was synthesized.

Pt serving as an electrode was sputter-deposited on a sapphire single-crystal substrate at 650 ° C., and oriented so that the [111] axis was perpendicular to the sapphire single-crystal substrate.

The coating solution was applied to the surface of the Pt electrode by a spin coater, dried, and then heat-treated at 420 ° C. for 1 minute, followed by crystallization heat treatment at 750 ° C. for 4 minutes. The operation of coating and heat treatment of the coating solution was repeated 12 times, and K (Sr _0.80 Ba _0.20 ) having a thickness of 0.96 μm was formed.
To obtain a ₂ Nb ₅ O ₁₅ thin film.

When the X-ray diffraction measurement was performed with reference to the reciprocal lattice of the sapphire substrate, the rocking curve obtained by rotating only the crystal at the (002) peak showed a mosaic degree of about 5 degrees in half width. [0] of the obtained thin film.
01] It was confirmed that the thin film was mainly composed of a tungsten bronze type crystal phase whose axis was oriented perpendicular to the substrate surface.

A gold electrode having a diameter of 0.2 mm was formed on the surface of the prepared thin film having a thickness of 0.96 μm by sputter deposition to prepare a thin film capacitor, which was then heat-treated at 500 ° C. for 10 minutes. LCR meter (42 made by Hewlett-Packard)
84A) at 25 ° C., 1 kHz (AC 100 m
Under the condition V), the relative dielectric constant and the dielectric loss were determined.

Further, the DC bias characteristics are defined as a relative dielectric constant K ₀ when no voltage is applied at room temperature, a DC electric field of 3 V
When the relative dielectric constant at the time of applying a voltage of / μm is K ₁ , the relative dielectric constant was determined by (K ₀ −K ₁ ) / K ₀ × 100, and is shown in Table 1.

Next, a gold electrode having a diameter of 0.05 mm was formed on the surface of the formed film having a thickness of 0.96 μm by sputter deposition to prepare a thin film capacitor, and then heat-treated at 500 ° C. for 10 minutes. For this thin film capacitor, use an impedance analyzer (HP4 manufactured by Hewlett-Packard Company).
291A, fixture HP16092A) and a microprobe were used to evaluate the characteristics at 1 MHz to 1.8 GHz. By measuring the impedance-frequency characteristics, the equivalent series capacitance at 100 MHz was evaluated, and the relative permittivity was determined.

The rate of change of capacitance at -25 ° C. (%)
Is the capacitance of -25 ° C. and C _-25, when the electrostatic capacitance of 25 ° C. was C _25, obtained in _{(C -25 -C 25) × 100} / C 25, the capacitance of 85 ° C. When the capacitance at 85 ° C. is C ₈₅ and the capacitance at 25 ° C. is C ₂₅ ,
Obtained in _{(C 85 -C 25) × 100} / C 25. These results are shown in Sample No. 14 of Table 1.

Similarly, the composition formula (1-
_{y) K (Sr 1-x} Ba x) 2 Nb 5 O 15 · 5y / 2 (S
Samples were prepared as shown in Table 1 by changing x and y of r _1-x Ba _x ) Nb ₂ O ₆ , and the characteristics were evaluated. It was confirmed that the obtained thin film of the present invention had a mosaic degree of 5 degrees and a thin film having a tungsten bronze structure in which the [001] axis was oriented perpendicular to the substrate surface. Table 1 shows the results.

[0056]

[Table 1]

As can be seen from Table 1, the dielectric thin film of the present invention has a high dielectric constant of 1000 or more at 100 MHz, a capacitance temperature change rate of less than ± 10%, and a dielectric loss of 2%. %, The relative dielectric constants at 1 kHz and 100 MHz are 10
It can be seen that it is lower than 00, the dielectric loss is 2% or more, or the temperature change rate of the capacitance is ± 10% or more.

In the case of a thin film (y> 0) in which (Sr _{1 -x} Ba _x ) Nb ₂ O ₆ is further dissolved, the relative dielectric constant is slightly lowered, but the DC bias characteristic and the temperature change of the capacitance are obtained. It turns out that rate TCC improves.

The sample No. 26 in Table 1 describes K (Sr _0.75 Ba _0.25 ) ₂ Nb ₅ O ₁₅ disclosed in the above-mentioned document. The measurement frequency is 10 kHz.

[0060]

As described in detail above, the dielectric thin film of the present invention does not contain lead and therefore has a small environmental effect, has excellent temperature characteristics of capacitance, has a small dielectric loss, and has a low dielectric loss.
Even at high frequencies such as MHz, the relative dielectric constant is large,
The element can be reduced in size, and can be widely applied as a capacitor used at a high frequency such as a decoupling capacitor around an IC.

Claims (5)

[Claims] 1. A dielectric thin film having a thickness of 2 μm or less and comprising a tungsten bronze type crystal phase containing K, Sr and Nb as metal elements, wherein the composition formula based on the molar ratio of the metal element oxide is (1-y _{) K (Sr 1-x Ba} x) 2 Nb 5 O 15 · 5y /
2 (Sr _1-x Ba _x ) Nb ₂ O ₆ , where x and y are y = 0 and 0 ≦ x ≦ 0.
20 or 0 <y ≦ 0.10 and 0.
A dielectric thin film that satisfies a relational expression of 05 ≦ x ≦ 0.25. 2. The dielectric thin film according to claim 1, wherein the [001] axis is mainly composed of a tungsten bronze type crystal phase oriented in the thickness direction. 3. A dielectric constant of 1000 or more at a measurement frequency of 1 kHz (room temperature) and a measurement frequency of 100 M
3. The dielectric thin film according to claim 1, wherein a relative dielectric constant at Hz (room temperature) is 1000 or more. 4. A ceramic capacitor comprising a pair of electrodes formed on both surfaces of the dielectric thin film according to claim 1. 5. The ceramic capacitor according to claim 4, wherein the electrode is Pt or Au whose [111] axis is oriented in the thickness direction.