JP2003218227A - High-dielectric thin-film capacitor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor using a dielectric thin film of a high dielectric constant and having a small leakage current and a high dielectric breakdown voltage. <P>SOLUTION: This high-dielectric thin-film capacitor is manufactured in such a way that an upper electrode and a lower electrode are respectively formed on the upper and the lower faces of the high-dielectric thin film, wherein the high-dielectric thin film having a perovskite structure is predominantly oriented to the (111) plane, the upper and the lower electrodes on the high-dielectric thin film have a face-centered cubic structure, the electrode thin films are predominantly oriented to the (111) plane, and the high-dielectric thin film is formed at a temperature of 300°C or lower. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film capacitor using a high dielectric thin film, and more particularly, it can be applied to an electronic device such as a mobile phone or a personal digital assistant using a small and lightweight capacitor called a chip capacitor. is there.

[0002]

2. Description of the Related Art In recent years, miniaturization of electronic devices such as mobile phones,
Thinning is required. The electronic device is composed of a circuit board or the like on which electronic parts such as an IC and a capacitor are mounted,
Electronic components and circuit boards used are also required to be thin. In order to realize a small and thin capacitor, it is composed of a laminated structure of electrode thin film and high dielectric thin film on a small, lightweight, low cost substrate such as glass, ceramic, metal foil, or organic polymer film. Small and lightweight capacitors are offered.

[0003]

When the high dielectric thin film is formed on the electrode thin film, the high dielectric thin film is oriented in random directions depending on the film forming conditions and is mainly affected by the substrate. The (110) plane, the (111) plane, and the (200) plane are preferentially oriented. However, as a result of the high dielectric thin film oriented other than the (111) plane having a smaller dielectric polarization than the high dielectric thin film oriented in the (111) plane, the dielectric constant becomes low. Furthermore, if the orientation is other than the (111) plane, the unevenness of the surface becomes large, and a film with rough crystal grain boundaries is formed.

Such surface irregularities and rough crystal grain boundaries deteriorate the contact state with the electrode thin film, and recombination of carriers at the crystal grain boundaries and the interface with the electrode becomes dominant, resulting in leakage. The current increases, resulting in a capacitor having a low withstand voltage.

According to the present invention, a high dielectric thin film having a perovskite structure is preferentially oriented in the (111) plane to have a large dielectric constant, and a flat surface form is obtained.
By providing a high-dielectric thin film with dense grain boundaries,
It is an object of the present invention to provide a high-dielectric-constant thin film capacitor having a high dielectric constant, a high dielectric strength, and high quality and high reliability.

[0006]

In order to achieve the above-mentioned object, the present invention is a method for manufacturing a high dielectric thin film capacitor in which an upper electrode and a lower electrode are formed on the upper and lower surfaces of a high dielectric thin film, which is a perovskite structure. The orientation of the high-k dielectric thin film having is preferentially oriented to the (111) plane, and the upper and lower electrodes of the high-dielectric thin film have a face-centered cubic structure, and the orientation of the electrode thin film is the (111) plane. The high dielectric thin film is formed so as to be preferentially oriented, and the formation temperature of the high dielectric thin film is set to 300 ° C. as an upper limit. As a result, the dielectric polarization of the high-dielectric thin film increases, resulting in an increase in the dielectric constant. Furthermore, it becomes possible to provide a high-dielectric thin film having a flat surface morphology and dense crystal grain boundaries, and it is possible to provide a capacitor with a small leak current and an excellent withstand voltage.

Further, since the lower electrode of the high dielectric thin film has a face-centered cubic structure and the orientation of the electrode thin film is preferentially oriented to the (111) plane, the high dielectric thin film formed on the lower electrode is Lattice matching becomes possible, and a high dielectric thin film having a low density of defect states at the bonding interface and an electrode thin film can be bonded.

As a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

In the above capacitor, the upper electrode of the high dielectric thin film has a face-centered cubic structure, and the orientation of the electrode thin film is preferentially oriented to the (111) plane. The dielectric thin film can be lattice-matched, and the high dielectric thin film having a low density of defect states at the bonding interface can be bonded to the electrode thin film. As a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to an embodiment of the present invention, there is provided a high dielectric thin film capacitor in which an upper electrode and a lower electrode are formed on the upper and lower surfaces of a high dielectric thin film, the orientation of the high dielectric thin film having a perovskite structure. Is preferentially oriented to the (111) plane,
Moreover, the upper electrode and the lower electrode of the high dielectric thin film have a face-centered cubic structure, and the orientation of the electrode thin film is preferentially oriented to the (111) plane. As the dielectric polarization of the thin film increases, the dielectric constant increases. Furthermore, it becomes possible to provide a high-dielectric thin film having a flat surface morphology and dense crystal grain boundaries, and it is possible to provide a capacitor with a small leak current and an excellent withstand voltage.

Further, since the lower electrode of the high dielectric thin film has a face-centered cubic structure and the orientation of the electrode thin film is preferentially oriented to the (111) plane, the high dielectric thin film formed on the lower electrode is Lattice matching becomes possible, and a high dielectric thin film having a low density of defect states at the bonding interface and an electrode thin film can be bonded.

As a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

In the above capacitor, the upper electrode of the high dielectric thin film has a face-centered cubic structure, and the orientation of the electrode thin film is preferentially oriented to the (111) plane. The dielectric thin film can be lattice-matched, and the high dielectric thin film having a low density of defect states at the bonding interface can be bonded to the electrode thin film. As a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

Further, in the above capacitor, the lattice mismatch between the high dielectric thin film and the electrode thin film is limited to 5%. As a result, the lattice mismatch between the upper and lower electrodes and the high dielectric thin film becomes small, and the high dielectric thin film having a low defect level density at the bonding interface and the electrode thin film can be bonded. As a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

In the capacitor, the lattice constant of the high dielectric thin film is larger than that of the electrode thin film. As a result, a compressive in-plane stress is applied to the high-dielectric thin film, and a large dielectric polarization is generated to generate a large dielectric constant, and it is possible to provide a capacitor with a small leak current and excellent withstand voltage. is there.

Further, the capacitor is characterized in that the substrate has an amorphous structure or a crystalline structure and does not affect the orientation of the high dielectric thin film and the electrode thin film.
As a result, the electrode thin film formed on the substrate has the (111) plane, which is a close-packed facet of face-centered cubic crystal, oriented parallel to the substrate, and the lattice matching between the upper and lower electrodes and the high dielectric thin film becomes possible. A high dielectric thin film having a low density of defect states at the bonding interface and an electrode thin film can be bonded. As a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

Further, in the above-mentioned capacitor, it is preferable that the substrate is at least one substance selected from the group consisting of glass, ceramics, metal foil, organic polymer, and semiconductor substrate. As a result, the electrode thin film formed on the substrate is preferentially oriented to the (111) plane, and it is possible to provide a capacitor having a large dielectric constant and a small leak current and excellent in withstand voltage.

In the capacitor, the high dielectric thin film is preferably at least one substance selected from the group consisting of SrTiO ₃ , BaTiO ₃ and PbTiO ₃ . As a result, it is possible to provide a capacitor having a large dielectric constant and a small leakage current and an excellent withstand voltage.

In the capacitor, the electrode thin film is preferably at least one substance selected from the group consisting of Pt, Ag, Au, Cu, Ni, Al, Pd, Ru and Ir. As a result, the lattice mismatch with the high dielectric thin film is reduced, and as a result, it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

Next, in the method of manufacturing a high dielectric thin film capacitor according to the embodiment of the present invention, a high dielectric thin film having a perovskite structure is preferentially oriented to the (111) plane. Is a method of manufacturing a high dielectric thin film capacitor.

In the above method, it is preferable to use means selected from the group consisting of RF magnetron sputtering method and ECR magnetron sputtering method as the method for forming the high dielectric thin film. As a result, it is possible to form a high-dielectric thin film having a high relative permittivity, and it is possible to provide a capacitor having a large permittivity and a small leak current and an excellent withstand voltage.

Further, in the above method, it is preferable that the upper limit of the film formation pressure in the RF magnetron sputtering method or the ECR magnetron sputtering method is 3 × 10 ⁻³ Torr. As a result, it is possible to form a high-dielectric thin film that is preferentially oriented on the (111) plane, and it is possible to provide a capacitor having a large dielectric constant and a small leak current and an excellent withstand voltage.

In the above method, it is preferable that the upper limit of the temperature for forming the high dielectric thin film is 300 ° C. This makes it possible to apply Al, Cu, or Ni, which easily oxidizes, as an electrode material, and it is possible to provide a capacitor that has a low cost, a large dielectric constant, and a small leak current and an excellent withstand voltage.

In the above method, it is preferable that the lower limit of the deposition rate of the high dielectric thin film is 10 nm / min.
As a result, the high dielectric thin film formation time is shortened,
The manufacturing throughput can be improved, and it is possible to provide a capacitor that has a low cost, a large dielectric constant, a small leak current, and an excellent withstand voltage.

In the above method, the lower limit of the deposition rate of the electrode thin film is preferably 10 nm / min. As a result, the time for forming the electrode thin film can be shortened, and as a result, the manufacturing throughput can be improved, and it is possible to provide a capacitor that is low in cost, has a large dielectric constant, and has a small leak current and an excellent withstand voltage.

Next, in the method for manufacturing a high dielectric thin film capacitor according to the embodiment of the present invention, the lower and upper electrodes of the high dielectric thin film have a face-centered cubic structure, and the orientation of the electrode thin film is (1
11) A method for manufacturing a high dielectric thin film capacitor for forming a preferentially oriented electrode thin film on a surface.

In the above method, it is preferable to use a means selected from the group consisting of a DC magnetron sputtering method, an RF magnetron sputtering method, an ECR magnetron sputtering method, a vacuum deposition method and a CVD method as a method for forming the electrode thin film. This makes it possible to easily form an electrode thin film in which the orientation of the electrode thin film is preferentially oriented on the (111) plane, and it is possible to provide a capacitor having a large dielectric constant and a small leak current and excellent withstand voltage. Is.

In the above method, it is preferable that the lower limit of the deposition rate of the electrode thin film is 10 nm / min. As a result, the time for forming the electrode thin film can be shortened, and as a result, the manufacturing throughput can be improved, and it is possible to provide a capacitor that is low in cost, has a large dielectric constant, and has a small leak current and an excellent withstand voltage.

The high dielectric thin film capacitor manufactured according to the present invention has a high dielectric thin film having a perovskite structure preferentially oriented to the (111) plane, resulting in a large dielectric polarization and a flat surface morphology. It is a high-dielectric thin-film capacitor having a high-dielectric thin film with a dense field, a large dielectric constant, and an excellent withstand voltage and high quality and high reliability. In other words, by using this high dielectric thin film capacitor, it can be mounted as a chip capacitor in small and lightweight electronic devices, and is a flexible low-capacity chip for smoothing, tuning, decoupling, etc. It can be used as a capacitor.

Hereinafter, the present invention will be described in more detail with reference to the drawings using embodiments.

(First Embodiment) FIG. 1 shows the structure of a high dielectric thin film capacitor according to the first embodiment.

In FIG. 1, 1 is a substrate, 2 is an electrode thin film,
3 is a high dielectric thin film. Borosilicate glass was used as the substrate, Pt was used as the electrode thin film, and SrTiO ₃ was used as the high dielectric thin film.

After the Pt thin film of the electrode was formed on the glass substrate by the DC magnetron sputtering method, the SrTiO ₃ thin film was formed by the RF magnetron sputtering method. Subsequently, a Pt thin film as an electrode was formed by a DC magnetron sputtering method to obtain a high dielectric thin film capacitor. The capacitor characteristics could be confirmed in the above sample.

As the high dielectric thin film, SrTiO ₃ , BaTiO ₃ , and PbTi which can obtain a high relative dielectric constant are used.
It is preferably at least one substance selected from the group consisting of O ₃ and solid solutions thereof.

As the method for forming the high dielectric thin film, it is preferable to use the RF magnetron sputtering method or the ECR magnetron sputtering method.

The deposition rate of the high dielectric thin film is 1 per minute.
The lower limit is preferably 0 nm.

As the electrode thin film, Pt, Ag, Au, C
It is preferably at least one substance selected from the group consisting of u, Ni, Al, Pd, Ru and Ir.

The formation temperature of the high dielectric thin film is 300 ° C.
The following is preferable.

The electrode thin film is formed by DC magnetron sputtering, RF magnetron sputtering, ECR.
It is preferable to use a magnetron sputtering method, a vacuum evaporation method, or a CVD method.

The deposition rate of the electrode thin film is 10 n / min.
It is preferable that m is the lower limit.

[0041]

EXAMPLES Specific examples of the present invention will be described below.

(Example 1) As a first example, in the high dielectric thin film capacitor of FIG. 1, a glass substrate having a thickness of 0.5 mm was formed on the glass substrate by DC magnetron sputtering.
A lower electrode was formed. The sputtering condition of the electrode thin film is 10
^-6 Torr high vacuum chamber in Ar atmosphere, DC power 200W, film forming pressure 8 × 10 ^-3 Torr,
It was carried out under the condition that the substrate temperature was 25 ° C. The film thickness is about 1000Å,
The vapor deposition rate was about 100Å / min. The electrode shape is formed in a size of 5 mm square using a metal mask. After forming the lower electrode, a high dielectric thin film of SrTiO ₃ was formed. The sputtering conditions for the SrTiO ₃ thin film were Ar / in a high vacuum chamber on the order of 10 ⁻⁶ Torr.
RF power 800 in a mixed atmosphere of O ₂ = 2/1
It was performed under the conditions of W and a substrate temperature of 300 ° C. Deposition pressure is 2 ×
It was formed under two conditions of 10 ⁻³ Torr and 8 × 10 ⁻³ Torr. The thickness of the SrTiO ₃ thin film was about 3000Å and the film deposition rate was about 300Å / min. The surface area of the SrTiO ₃ thin film on the Pt lower electrode was 4 × 4 mm. S
After forming the rTiO ₃ thin film, a Pt electrode was formed again as an upper electrode. The conditions for forming the upper electrode are the same as those for the lower electrode. The surface area of the SrTiO ₃ thin film sandwiched between the electrodes was 3 × 3 mm.

The above two types of Pt / SrTiO ₃ / Pt
The crystal orientation of the structural laminated film analyzed by X-ray diffraction (XRD) is shown in FIG. From the X-ray diffraction pattern, the SrTiO ₃ thin film formed at a film formation pressure of 2 × 10 ⁻³ Torr was preferentially oriented to the (111) plane, and the peak formed at 8 × 10 ⁻³ Torr was (110) for the SrTiO ₃ thin film. It can be seen that the plane is preferentially oriented.

The above two kinds of Pt / SrTiO ₃ / Pt
The surface morphology of the SrTiO ₃ thin film surface of the structural laminated film analyzed by using a scanning electron microscope (SEM) is shown in FIG. X
Combined with the RD results, it can be seen that the SrTiO ₃ thin film preferentially oriented to the (111) plane has small surface irregularities and dense crystal grain boundaries. On the other hand, it can be seen that the SrTiO ₃ thin film preferentially oriented to the (110) plane has large surface irregularities and rough crystal grain boundaries.

Table 1 shows the results of evaluating the capacitor characteristics using the above two types of high dielectric thin film capacitors. The measurement frequency is 1 kHz. Further, the voltage at the time of measuring the leak current is + 5V applied to the lower electrode.

[0046]

[Table 1]

As can be seen from Table 1, 2 × 10 ⁻³ T
The SrTiO ₃ thin film formed by orr has a dielectric constant of 80,
While the current density was 2.6 × 10 ⁻⁷ mA / cm ² , the SrTiO ₃ thin film formed at 8 × 10 ⁻³ Torr had a dielectric constant of 60 and 5.3 × 10 ⁻⁵ mA / cm _3. The current density was cm ² .

These differences in permittivity reflect the fact that SrTiO ₃ is preferentially oriented in the (111) plane and thus the dielectric polarization is increased, thereby increasing the permittivity. Pt addition, the difference in current density is a result of reflecting the orientation of the difference in the SrTiO ₃ thin film, SrTiO ₃ thin film oriented in the (110) plane due to irregularities and coarse grain boundaries of the surface observed by SEM The joint condition with
This is because the defect level at the SrTiO ₃ / Pt junction interface was increased and the leak current was increased. tan
The same phenomenon has been confirmed for δ. Further, regarding the dielectric constant, the result shows that the higher the film forming pressure is, the higher the vacuum becomes. This is because the high-dielectric thin film is preferentially oriented by the (111) plane due to the high-vacuum film formation to increase the dielectric polarization, and the dielectric constant is improved accordingly. In addition,
The film forming pressure shows preferential orientation to the (111) plane 6
It is preferable to form the film at a pressure lower than × 10 ^-3 Torr.

Therefore, the high dielectric thin film of the perovskite structure is preferentially oriented in (111), so that the dielectric constant is large, the surface irregularities are small, and the crystal grain boundaries are dense.
As a result of good bonding with the electrode thin film, it is possible to provide a capacitor having a small leak current and an excellent withstand voltage.

(Example 2) As a second example, SrTiO ₃ preferentially oriented to the (111) plane used in Example 1 was used.
A similar experiment was performed using a thin film and using Cr having a body-centered cubic crystal structure as an electrode material. Otherwise, the conditions are the same as in Example 1.

The above two types of Pt / SrTiO ₃ / Pt
FIG. 4 shows the crystal orientations of the structural laminated film and the Cr / SrTiO ₃ / Cr structural laminated film analyzed by X-ray diffraction (XRD). From the X-ray diffraction pattern, since Pt has a face-centered cubic crystal structure, it is preferentially oriented to the (111) plane, which is a close-packed plane. On the other hand, since Cr has a body-centered cubic structure, it is understood that it is preferentially oriented to the (110) plane, which is a close-packed surface.

Table 2 shows the characteristics of each high dielectric thin film capacitor.

[0053]

[Table 2]

As a result of the experiment, both SrTiO ₃ thin films (1
Since the 11) plane was preferentially oriented, there was no significant difference in the dielectric constant. However, P having a face-centered cubic crystal structure
The t electrode had a current density of 2.6 × 10 ⁻⁷ mA / cm ² , whereas the Cr electrode having a body-centered cubic crystal structure had a current density of 8.2 × 10 ⁻⁵ mA / cm ² . Met.
Since the SrTiO ₃ thin film is preferentially oriented in the (111) plane and therefore has small irregularities and dense crystal grain boundaries, the difference in the current densities is due to the crystal structure and orientation of the electrode material. The result reflects the difference. Figure 5 shows SrTiO
₃ shows the crystal structure of Pt and Cr. SrTiO ₃ is S
O in the face-centered position and Ti in the body-centered position in the cubic crystal lattice of r.
Are occupied by. When the SrTiO ₃ thin film is oriented in the (111) plane, the (111) plane surrounded by Sr is oriented in parallel with the substrate. On the other hand, in the electrode material, Pt has a face-centered cubic crystal structure and is oriented so that the (111) plane, which is a close-packed plane, is parallel to the substrate.
On the other hand, Cr has a body-centered cubic crystal structure and is oriented so that the (110) plane, which is a close-packed plane, is parallel to the substrate.

Further, each lattice constant is SrTiO 3.
₃Is a = 3.91Å, Pt is 3.924Å, and Cr is 2.
It is 885Å. Therefore, SrT on the Pt (111) plane
iO ₃When the (111) plane grows, the lattice mismatch is 0.4%
And grow with a small lattice mismatch. On the other hand, Cr (1
10) SrTiO on the surface₃When the (111) plane grows
Child mismatch becomes 9.6, and grows with a large lattice mismatch
It will be. As a result, Pt / Sr with a small lattice mismatch
TiO₃In bonding, the interface state is good and the defect level is low.
As a result, the leakage current becomes smaller. On the other hand, lattice irregularity
Larger Cr / SrTiO 3₃Poor interface condition in joining
As a result, the defect level increases and the leak current increases.
Become.

A SrTiO ₃ thin film was formed on the Cr electrode.
Sr by forming at a film forming pressure of × 10 ^-3 Torr
A laminated film of TiO ₃ (110) plane preferred orientation / Cr (110) plane orientation was formed. In this case, the lattice mismatch was 26.
As a result, the interface state became worse and the defect level increased, resulting in a large leakage current of 5.4 × 10 ⁻³ mA / cm ² . Furthermore, the large irregularities and the rough crystal grain boundaries of the (110) -oriented SrTiO ₃ thin film confirmed in Example 1 also affect the large leak current.

Further, it has been confirmed that tan δ has the same tendency as the current density.

Therefore, the lower and upper electrode thin films of the high dielectric thin film preferentially oriented to the (111) plane have a face-centered cubic crystal structure, and the orientation of the electrode thin film is preferentially oriented to the (111) face. As a result, lattice matching of the high dielectric thin film formed between the lower electrode and the upper electrode becomes possible, and the high dielectric thin film having a low defect level density at the bonding interface and the electrode thin film can be bonded. As a result, it is possible to provide a capacitor having a large dielectric constant and a small leakage current and an excellent withstand voltage.

The lattice mismatch between the high dielectric thin film and the electrode thin film is preferably set to 5% as an upper limit. If the lattice mismatch exceeds 5%, the leak current increases and the dielectric strength characteristics deteriorate.

(Example 3) As a third example, SrTiO ₃ used in Example 1 and preferentially oriented to the (111) plane was used.
A similar experiment was performed using a thin film and using Pt having a small lattice mismatch and an AlNi alloy electrode having a slightly larger lattice mismatch as the electrode material. Otherwise, the conditions are the same as in Example 1. The AlNi alloy is Al: Ni = 5.
As a result of precise lattice constant measurement by XRD at 5:45, the lattice constant was a = 3.85Å. It has been confirmed by XRD analysis that the SrTiO ₃ thin film is oriented in the (111) plane.

Table 3 shows the characteristics of each high dielectric thin film capacitor.

[0062]

[Table 3]

As a result of the experiment, both tan δ and current density were not significantly changed in both Pt and AlNi electrodes, and the result was that the dielectric constant was improved. This reflects the result of dielectric polarization is increased by took plane compressive stress to the SrTiO ₃ thin film by the lattice constant of the AlNi electrode material than SrTiO ₃ thin film was reduced. The experimental results show that even in the SrTiO ₃ thin film oriented in the (111) plane, the dielectric constant is improved when the in-plane compressive stress is applied.

Therefore, since the lattice constant of the high dielectric thin film is larger than that of the electrode thin film, compressive in-plane stress is applied to the high dielectric thin film, and a large dielectric polarization is generated, so that the dielectric constant is increased. It is possible to provide a capacitor that is large and has a small leakage current and an excellent withstand voltage.

The lattice mismatch between the high dielectric thin film and the electrode thin film is preferably 5% as an upper limit. If the lattice mismatch exceeds 5%, the leak current increases and the dielectric strength characteristics deteriorate.

(Example 4) As a fourth example, SrTiO ₃ used in Example 1 and preferentially oriented to the (111) plane was used.
The same experiment was conducted using a thin film and using a 100 μm thick stainless steel foil instead of the glass substrate used in Example 1. Otherwise, the conditions are the same as in Example 1. Since the stainless steel foil is electrically conductive, it causes a short circuit between the upper and lower electrodes, so the Ti (OC ₂
H ₅ ) ₄ hydrolysis reaction using sol-gel method to produce Ti
O ₂ was formed. The thickness of TiO ₂ is about 500Å. As a result of analysis using XRD, both laminated films showed similar diffraction patterns.

Table 4 shows the characteristics of each high dielectric thin film capacitor.

[0068]

[Table 4]

As a result of the experiment, the same characteristics were obtained in both the glass and stainless steel substrates without any significant change in dielectric constant, tan δ and current density. The same tendency could be obtained by using ceramic, metal foil, organic polymer, silicon (100) substrate, or GaAs (100) substrate as the substrate material other than glass.

Therefore, since the substrate has an amorphous structure or a crystalline structure and does not affect the orientation of the high dielectric thin film and the electrode thin film, the electrode thin film formed on the substrate has a face-centered cubic crystal closely packed surface. The (111) plane is oriented parallel to the substrate, and the high dielectric thin film formed thereon is oriented to the (111) plane, which enables lattice matching between the upper and lower electrodes and the high dielectric thin film. It is possible to bond a high dielectric thin film having a low density of defect states at the bonding interface and an electrode thin film. As a result, it is possible to provide a capacitor having a large dielectric constant and a small leakage current and an excellent withstand voltage.

Example 5 As a fifth example, B was used in place of the high dielectric thin film of SrTiO ₃ used in Example 1.
aTiO ₃ , PbTiO ₃ , and (Ba _0.2 S of solid solution)
The same experiment as in Example 1 was performed using r _0.8 ) TiO ₃ and (Pb _0.1 Sr _0.9 ) TiO ₃ and BiTiO ₃ as a comparative example. BaTiO ₃ , PbTiO ₃ , (Ba _0.2 Sr _0.8 ) T
The conditions for forming iO ₃ , (Pb _0.1 Sr _0.9 ) TiO ₃ , and BiTiO ₃ are the same as in Example 1.

As a result of analysis using XRD, when each high dielectric thin film was formed at a film forming pressure of 2 × 10 ⁻³ Torr, all were preferentially oriented to the (111) plane.

Table 5 shows the dielectric constants of the flexible thin film capacitors manufactured by using the respective dielectric thin films.

[0074]

[Table 5]

As a result of the experiment, a high dielectric constant, a low tan δ, and a current density could be obtained in all the dielectric thin films except BiTiO ₃ . Further, in each high dielectric material, the film forming pressure is set to 8 × 10 ⁻³ Torr (11
Pt electrode capacitors were prepared by forming a preferentially oriented high-dielectric thin film on the (0) plane, but all capacitors showed a higher dielectric constant when the high-dielectric thin film was oriented on the (111) plane.

Therefore, the high dielectric thin film is made of SrTiO ₃ , B.
It is at least one substance selected from the group consisting of aTiO ₃ and PbTiO ₃ , and it is possible to provide a capacitor having a large dielectric constant and a small leakage current and an excellent withstand voltage by being preferentially oriented to the (111) plane. It is possible.

Example 6 As a sixth example, SrTiO ₃ preferentially oriented to the (111) plane used in Example 1 was used.
Using a thin film, instead of Pt used in Example 1, A
A similar experiment was performed using l. Otherwise, the conditions are the same as in Example 1.

Table 6 shows the characteristics of each high dielectric thin film capacitor.

[0079]

[Table 6]

As a result of the experiment, even if Al was used, it was possible to obtain characteristics almost equivalent to those of Pt. In addition to Pt, Ag, Au, Cu, Ni, Al, Pd, Ru is used as the electrode material.
A similar tendency could be obtained using Ir and Ir and these alloys. The use of these electrode materials reduces the lattice mismatch with the high dielectric thin film, and as a result, it is possible to provide a capacitor having a small leak current and an excellent withstand voltage.

(Embodiment 7) As a seventh embodiment, SrT
The ECR magnetron sputtering method was used as the method for forming the iO ₃ thin film. As a condition of ECR sputtering, 10 ^-6 T
Ar / O ₂ = 2 in high vacuum chamber of orr level
In a mixed atmosphere of / 1, the RF power was 600 W, the microwave power was 400 W, and the substrate temperature was 300 ° C. The film forming pressure was 2 × 10 ⁻³ Torr. SrT
The thickness of the iO ₃ thin film is about 3000Å and the film deposition rate is about 30.
There was 0Å / min. Otherwise, the conditions are the same as in Example 1.

As a result of the experiment, it was possible to obtain a tendency similar to that of Example 1 as the capacitor characteristic.

Therefore, RF is used as a method for forming a high dielectric thin film.
By using means selected from the group consisting of magnetron sputtering method and ECR magnetron sputtering method, it is possible to provide a capacitor exhibiting a high dielectric constant and having a small leak current and an excellent withstand voltage.

Example 8 As an eighth example, SrTiO ₃ used in Example 1 and preferentially oriented to the (111) plane was used.
Using a thin film, the formation temperature of the high dielectric thin film is 300 ° C.
And an experiment was conducted under two conditions of 400 ° C. Al was used as the electrode material, and the other conditions were the same as in Example 1.

Table 7 shows the characteristics of each high dielectric thin film capacitor.

[0086]

[Table 7]

When the substrate temperature reaches 400 ° C., all the capacitor characteristics are deteriorated. When the substrate temperature rises, the surface of Al of the electrode material is oxidized to form an Al oxide film of a low dielectric constant layer, the dielectric constant decreases, and tan δ also increases. In addition, the interface current between the Al oxide film and the SrTiO ₃ thin film becomes poor, and the leak current is also increased.

Therefore, the formation temperature of the high dielectric thin film is 300.
Al and C that are apt to oxidize when the upper limit is ℃
Since u and Ni can be applied as electrode materials, it is possible to provide a capacitor that is low in cost and has a small leak current and an excellent withstand voltage.

(Example 9) As a ninth example, the SrTiO ₃ preferentially oriented to the (111) plane used in Example 1 was used.
Using the thin film, the deposition rate of the high dielectric thin film when the RF power was increased was investigated. Otherwise, the conditions are the same as in Example 1.

As a result of the experiment, the deposition rate increased linearly as the RF power increased. SrTi with increasing deposition rate
No change in the orientation of the O ₃ thin film was confirmed. Further, the dielectric constant of the capacitor did not extremely deteriorate even when the RF power was increased to increase the deposition rate. Also, the leak current did not increase extremely. The improvement of vapor deposition rate leads to the improvement of throughput, and the cost reduction of high dielectric thin film capacitors can be realized. If the characteristics do not deteriorate, a higher deposition rate is preferable, and in this example, an extreme decrease in dielectric constant and an increase in leak current were not observed.

Therefore, as the lower limit of the formation rate of the substantial high dielectric thin film is set to 10 nm, the time required for forming the high dielectric thin film is shortened. As a result, the manufacturing throughput can be improved, the cost is low and the dielectric constant is low. It is possible to provide a capacitor that is large and has a small leak current and an excellent withstand voltage.

(Example 10) As a tenth example, the same experiment was performed by using EB vapor deposition as the method of forming the Pt electrode used in Example 2. EB deposition is 10 ^-6 Torr
The substrate temperature was 25 ° C. in the high vacuum chamber of the table. The conditions are the same as those in the second embodiment except that the metal electrode is formed.

As a result of XRD analysis, Pt was (111)
It was confirmed that the plane was preferentially oriented. Further, the capacitor characteristics were similar to those of the capacitor using the Pt electrode of Example 2. As a method of forming the metal electrode, D
Almost the same effect can be obtained by using C magnetron sputtering method, ECR magnetron sputtering method, vacuum deposition method, and CVD method, but from the viewpoint of automation and continuity of the vacuum device, DC magnetron sputtering method or RF magnetron sputtering method. It is preferable to use the method.

Therefore, as a method of forming the electrode thin film, a DC magnetron sputtering method, an RF magnetron sputtering method, E
By using a means selected from the group consisting of CR magnetron sputtering method, vacuum deposition method and CVD method, it becomes possible to easily form an electrode thin film in which the orientation of the electrode thin film is preferentially oriented to the (111) plane, Has a high dielectric constant,
It is possible to provide a capacitor having a small leak current and an excellent withstand voltage.

(Example 11) As an eleventh example, SrTi preferentially oriented to the (111) plane used in Example 1 was used.
Using the O ₃ thin film, the deposition rate of the electrode thin film when the DC power was increased was examined. Otherwise, the conditions are the same as in Example 1.

As a result of the experiment, the deposition rate increased linearly with the increase of DC power. No change in the orientation of the Pt thin film with the increase in the deposition rate was confirmed. Further, the dielectric constant of the capacitor did not extremely deteriorate even if the DC power was increased to increase the deposition rate. The leak current also did not increase extremely. The improvement of the deposition rate leads to the improvement of the throughput and the cost reduction of the high dielectric thin film capacitor can be realized. If the characteristics do not deteriorate, a higher deposition rate is preferable, and in this example, neither extreme decrease in dielectric constant nor increase in leak current was observed.

Therefore, as the lower limit of the substantial electrode thin film formation rate is 10 nm, the time required for forming the electrode thin film is shortened. As a result, the manufacturing throughput can be improved, the cost is low, the dielectric constant is large, and the leakage current is large. It is possible to provide a capacitor having a small dielectric strength and excellent withstand voltage.

[0098]

According to the above-described method of the present invention, there is provided a method of manufacturing a high dielectric thin film capacitor in which an upper electrode and a lower electrode are formed on the upper and lower surfaces of a high dielectric thin film, the high dielectric thin film having a perovskite structure. Is preferentially oriented to the (111) plane, the upper electrode and the lower electrode of the high dielectric thin film have a face-centered cubic structure, and the orientation of the electrode thin film is (111).
A capacitor having a high dielectric constant, a small dielectric constant, a small leak current, and an excellent withstand voltage is provided by forming the high dielectric thin film so as to have a preferred orientation on the surface and by setting the formation temperature of the high dielectric thin film to an upper limit of 300 degrees. be able to.

The manufacturing method of the present invention can efficiently and rationally manufacture the high dielectric thin film capacitor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a high dielectric thin film capacitor of Embodiment 1 and Examples 1 to 11 of the present invention.

FIG. 2 Pt / SrTiO ₃ / Pt of Example 1 of the present invention
The figure which shows the X-ray diffraction pattern of a structural laminated film.

FIG. 3 is a diagram showing the surface morphology of a SrTiO ₃ thin film of Example 1 of the present invention.

FIG. 4 Pt / SrTiO ₃ / Pt of Example 2 of the present invention
Shows the X-ray diffraction pattern of the structural laminate film and Cr / SrTiO ₃ / Cr structure laminated film

FIG. 5: SrTiO ₃ and Pt of Example 2 of the present invention,
Diagram showing the crystal structure of Cr

[Explanation of symbols]

1 base 2 electrode thin film 3 High dielectric thin film

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masatoshi Kitagawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Uenoyama             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5F038 AC05 AC15 AC18 AC19 EZ20                 5F058 BA11 BC03 BF12 BJ04                 5F083 FR01 GA06 GA24 GA27 JA14                       JA15 JA36 JA37 JA38 PR21                       PR22

Claims (9)

[Claims] 1. A method of manufacturing a high dielectric thin film capacitor, wherein an upper electrode and a lower electrode are formed on upper and lower surfaces of a high dielectric thin film, wherein the orientation of the high dielectric thin film having a perovskite structure is (111) plane. The high dielectric thin film is preferentially oriented, and the upper electrode and the lower electrode of the high dielectric thin film have a face-centered cubic structure, and the orientation of the electrode thin film is preferentially oriented to the (111) plane. A method of manufacturing a high dielectric thin film capacitor, wherein the formation temperature is set to 300 degrees as an upper limit. 2. The orientation of the high dielectric thin film having a perovskite structure is preferentially oriented to the (111) plane, and the upper electrode and the lower electrode of the high dielectric thin film have a face-centered cubic structure.
The lower electrode, the high dielectric thin film, and the upper electrode are sequentially layered on the substrate so that the orientation of the electrode thin film is preferentially oriented to the (111) plane, and the formation temperature of the high dielectric thin film is A method for manufacturing a high dielectric thin film capacitor set so that the upper limit is 300 degrees. 3. A high dielectric thin film capacitor having an upper electrode and a lower electrode formed on the upper and lower surfaces of a high dielectric thin film, wherein the orientation of the high dielectric thin film having a perovskite structure is (1).
11) plane preferentially oriented, and the upper and lower electrodes of the high dielectric thin film have a face-centered cubic structure, and the orientation of the electrode thin film preferentially oriented to the (111) plane and the lower electrode of the high dielectric capacitor Are formed on a substrate, the formation temperature of the high dielectric thin film is set to 300 ° C. as an upper limit, the substrate has an amorphous structure or a crystalline structure, and the high dielectric thin film and the electrode thin film are oriented. High-dielectric thin-film capacitor characterized by not affecting performance. 4. The high dielectric thin film capacitor according to claim 3, wherein the lattice mismatch between the high dielectric thin film and the electrode thin film has an upper limit of 5%. 5. The high dielectric thin film capacitor according to claim 3, wherein the lattice constant of the high dielectric thin film is larger than the lattice constant of the electrode thin film. 6. The lower electrode of the high dielectric capacitor is formed on a substrate, and the substrate has an amorphous structure or a crystalline structure, and does not affect the orientation of the high dielectric thin film and the electrode thin film. The high dielectric thin film capacitor according to claim 3, which is characterized in that. 7. The high dielectric thin film capacitor according to claim 3, wherein the substrate is at least one substance selected from the group consisting of glass, ceramics, metal foils, organic polymers, and semiconductor crystals. . 8. The high-k dielectric thin film is SrTiO ₃ or BaTi.
The high dielectric thin film capacitor according to claim 3, which is at least one substance selected from the group consisting of O ₃ and PbTiO ₃ . 9. The electrode thin film is Pt, Ag, Au, Cu, N
The high dielectric thin film capacitor according to claim 3, which is at least one substance selected from the group consisting of i, Al, Pd, Ru, and Ir.