JP3349612B2 - Dielectric capacitor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric capacitor, and more particularly to an improvement in ferroelectricity.

FIG. 13 shows a conventional ferroelectric capacitor. A silicon oxide layer 4 is formed on a silicon substrate 2. A lower electrode 6 made of platinum is provided thereon. On the lower electrode 6, a ferroelectric layer of PZ
A T (PbZr _X Ti _1-X O3) film 8 is provided, and further thereon,
An upper electrode 10 made of platinum is provided. Thus, a ferroelectric capacitor is formed by the lower electrode 6, the PZT film 8, and the upper electrode 10.

The reason why platinum is used as the lower electrode 6 is as follows. PZ
The T film 8 must be formed on the alignment film. If formed on an amorphous film, ferroelectricity is impaired because the film is not oriented. On the other hand, the lower electrode 6
It must be formed in a state insulated from the silicon substrate 2. Therefore, the silicon oxide layer 4 is formed on the silicon substrate 2.
Is formed. This silicon oxide layer 4 is amorphous. Generally, a film formed on an amorphous film is a non-oriented film, but platinum has a property of being an oriented film even on an amorphous film. For this reason, platinum is used as the lower electrode.

[0004]

However, the above-mentioned conventional ferroelectric capacitors have the following problems.

First, depending on the type and composition of the ferroelectric,
The mismatch between the lattice constant of platinum and the lower electrode was increased, and ferroelectricity was likely to deteriorate.

[0006] Second, since platinum is easily permeable to oxygen,
There has been a problem that the ferroelectricity is reduced due to the escape of oxygen in the ferroelectric (PZT), repeated aging, and repetition of polarization inversion. That is, as shown in FIG. 14, oxygen in the ferroelectric material might escape from between the platinum columnar crystals.

[0007] Such a problem also occurs in a capacitor using a dielectric having a high dielectric constant.

The present invention solves the above-mentioned problems and has excellent ferroelectricity and high dielectricity, and has a ferroelectric capacitor or a high dielectric constant with little deterioration due to aging and repetition of polarization reversal. It is an object to provide a dielectric capacitor.

[0009]

In the present invention, the term "capacitor" refers to a structure in which electrodes are provided on both sides of an insulator, irrespective of whether it is used for accumulating electricity. , Including those having this structure.

[0010]

A ferroelectric capacitor according to claim 1 and a dielectric capacitor having a high dielectric constant according to claim 9 are matched with the lattice constant of the ferroelectric layer or the dielectric layer having a high dielectric constant. A lower electrode having an alloy layer of platinum and iridium having a mixing ratio selected to be, a dielectric layer formed on the lower electrode in contact with the alloy layer of the lower electrode, An upper electrode formed thereon.

[0011]

In the ferroelectric capacitor according to a third aspect and the dielectric capacitor having a high dielectric constant according to the thirteenth aspect, the lower electrode is formed on a silicon oxide layer formed on a substrate. The lower electrode has a bonding layer in contact with the silicon oxide layer below the alloy layer or the iridium layer.

The ferroelectric capacitor according to claim 4 uses PbZrTiO ₃ as the ferroelectric layer, uses Pt _Y Ir _1-Y as a lower electrode layer in contact with the ferroelectric layer, and sets Y to 0 to 0.
It is characterized by being between 0.5.

According to a fifth aspect of the present invention, there is provided a ferroelectric capacitor according to the fourth aspect, wherein the Y is set between 0.2 and 0.3.

In the ferroelectric capacitor of the present invention, Bi ₄ Ti ₃ O ₁₂ is used as a ferroelectric layer, Pt _Y Ir _1-Y is used as a lower electrode layer in contact with the ferroelectric layer, and Y is 0. .8.

The ferroelectric capacitor according to claim 6 and the dielectric capacitor having high dielectric constant according to claim 12 are selected to match the lattice constant of the ferroelectric layer or the dielectric layer having high dielectric constant. A lower electrode having an alloy layer of two or more conductors having a mixture ratio and different lattice constants; a ferroelectric layer or a dielectric layer formed on the lower electrode so as to be in contact with the alloy layer of the lower electrode; A dielectric layer or an upper electrode formed on the dielectric layer.

The ferroelectric capacitor of claim 8 and the dielectric capacitor having a high dielectric constant of claim 15 are characterized in that the alloy layer is an alloy layer containing at least iridium.

The ferroelectric capacitor according to the eighth aspect and the dielectric capacitor having a high dielectric constant according to the fourteenth aspect include a lower electrode, a ferroelectric layer or a dielectric layer formed on the lower electrode, and a ferroelectric layer. Or an upper electrode having an alloy layer of platinum and iridium formed on the dielectric layer and having a mixing ratio selected to match the lattice constant of the ferroelectric layer or the dielectric layer. Features.

[0019]

According to a fourteenth aspect of the present invention, there is provided a method of manufacturing a ferroelectric capacitor having a high dielectric constant, comprising the steps of: forming a ferroelectric layer or a dielectric having a high dielectric constant on a substrate by sputtering; Forming an alloy layer of platinum and iridium as a lower electrode having a mixing ratio selected to match the lattice constant of the body layer ; a ferroelectric layer or a dielectric layer so as to be in contact with the alloy layer And forming an upper electrode on the ferroelectric layer or the dielectric layer.

According to a fifteenth aspect of the present invention, there is provided a method of manufacturing a ferroelectric capacitor having a high dielectric constant, comprising the steps of: forming a silicon oxide layer on a substrate; Forming a bonding layer , a platinum-iridium alloy layer or an iridium layer having a mixing ratio selected to match a lattice constant of the ferroelectric layer or the dielectric layer on the bonding layer. Forming a lower electrode, forming a ferroelectric layer or a dielectric layer on the lower electrode, and forming an upper electrode on the ferroelectric layer or the dielectric layer. ing.

A method of manufacturing a ferroelectric capacitor according to claim 20 and a method of manufacturing a dielectric capacitor having a high dielectric constant according to claim 25 include a step of heat-treating the lower electrode at 400 ° C. or higher. I have.

In the method for manufacturing a ferroelectric capacitor according to claim 21 and the method for manufacturing a dielectric capacitor having a high dielectric constant according to claim 26, the heat treatment step also serves as a heat treatment for forming a dielectric layer. It is characterized by.

In the method for manufacturing a ferroelectric capacitor according to claim 22 and the method for manufacturing a dielectric capacitor having a high dielectric constant according to claim 27, the lower electrode is made of an alloy of two or more kinds of metals having different lattice constants. By changing the composition ratio, the lattice constant of the alloy is changed to match the lattice constant of the dielectric layer.

[0025]

The ferroelectric capacitor according to claim 1 and the dielectric capacitor having a high dielectric constant according to claim 11 are characterized by using a lower electrode having an alloy layer of platinum and iridium. Therefore, the lattice constant can be matched by changing the mixture ratio of platinum and iridium according to the type and composition of the ferroelectric or the dielectric having a high dielectric constant. Further, iridium contained in the alloy is more easily oxidized than platinum, and the oxidized iridium can prevent the escape of oxygen in the ferroelectric.

[0026]

The ferroelectric capacitor according to the third aspect and the dielectric capacitor having a high dielectric constant according to the thirteenth aspect are characterized in that a bonding layer in contact with the silicon oxide layer is provided below the lower electrode. Therefore, the adhesion between the ferroelectric layer and the dielectric layer having a high dielectric constant can be improved.

The ferroelectric capacitor according to claim 4 uses PbZrTiO ₃ as the ferroelectric layer, uses Pt _Y Ir _1-Y as a lower electrode layer in contact with the ferroelectric layer, and sets Y to 0 to 0.5.
And between. Therefore, both lattice constants are matched, and excellent ferroelectricity can be obtained.

In the ferroelectric capacitor according to the fifth aspect, Y is set between 0.2 and 0.3. Therefore, the lattice constants of the two can be more closely matched, and more excellent ferroelectricity can be obtained.

In the ferroelectric capacitor of the present invention, Bi ₄ Ti ₃ O ₁₂ is used as the ferroelectric layer, Pt _Y Ir _1-Y is used as the lower electrode layer in contact with the ferroelectric layer, and Y is 0. .8. Therefore, both lattice constants are matched, and excellent ferroelectricity can be obtained.

The ferroelectric capacitor according to claim 7 and the dielectric capacitor having high dielectric constant according to claim 14 have an alloy layer of two or more conductors having different lattice constants on the lower electrode. Therefore, it is easy to match the lattice constant with the dielectric layer by changing the ratio of the alloy.

The ferroelectric capacitor according to claim 8 and the dielectric capacitor having high dielectric constant according to claim 15 further include iridium in the alloy layer. Therefore, the escape of oxygen from the dielectric layer can be prevented by the oxidized iridium.

The ferroelectric capacitors according to the ninth and tenth aspects and the dielectric capacitors having a high dielectric constant according to the sixteenth and seventeenth aspects have an upper electrode provided with an alloy layer or an iridium layer of platinum and iridium. Therefore, it is possible to prevent oxygen in the ferroelectric from being released from the upper electrode by the oxidized iridium.

The method for manufacturing a ferroelectric capacitor according to claim 18 and the method for manufacturing a dielectric capacitor having a high dielectric constant according to claim 23 include a step of forming a bonding layer in contact with a silicon oxide layer below a lower electrode. are doing. Therefore, the adhesion between the ferroelectric layer and the dielectric layer having a high dielectric constant can be improved.

According to a nineteenth aspect of the present invention, there is provided a method of manufacturing a ferroelectric capacitor having a high dielectric constant, wherein an alloy layer of platinum and iridium or an iridium layer is formed as a lower electrode. A step of performing heat treatment at 700 or more. Therefore, iridium in the iridium layer or the alloy layer is oxidized, and escape of oxygen can be prevented.

In the method of manufacturing a ferroelectric capacitor according to a twentieth aspect and the method of manufacturing a dielectric capacitor having a high dielectric constant according to a twenty-fifth aspect, the heat treatment for forming the dielectric layer is performed together with the heat treatment of the lower electrode. It is characterized by: Therefore, the process can be simplified and the production can be performed efficiently.

That is, a dielectric capacitor having good ferroelectricity and high dielectric properties can be provided.

[0038]

FIG. 1 shows the structure of a ferroelectric capacitor according to an embodiment of the present invention. On a silicon substrate 2, a silicon oxide layer 4, a lower electrode 12, a ferroelectric layer 8, and an upper electrode 10 are provided. The lower electrode 12 is formed of an alloy layer of platinum and iridium.

FIG. 2 compares the physical properties of platinum and iridium. As is clear from this table, the physical properties of iridium are almost equal to those of platinum. Iridium has a lower resistivity than platinum and is a preferred material for electrodes. The lattice constant of platinum is 3.923 angstroms, while the lattice constant of iridium is 3.839.
Angstrom. Therefore, by changing the mixing ratio, the lattice constant of the alloy of platinum and iridium is
It can be set between 3.923 angstroms and 3.839 angstroms. That is, an appropriate lattice constant can be set according to the type and composition of the ferroelectric.

For example, a case where bismuth titanate Bi ₄ Ti ₃ O ₁₂ (hereinafter referred to as BIT) is used as the ferroelectric layer 8 will be described. The lattice constant of BIT is a = 5.45,
b = 5.41 and c = 32.815. On the other hand, platinum or iridium as the lower electrode 12 is oriented in the (111) direction as shown in FIG. Therefore, in order to obtain a c-axis oriented film of BIT, the interatomic distance L of the (111) plane of the lower electrode 12 is set to a = 5.45 or b = 5.41.
Must be equal to In this embodiment, the composition ratio of the alloy of platinum and iridium is expressed as x = Pt _X Ir _1- x
By setting it to 0.8, the interatomic distance L of the (111) plane is obtained.
Can be set to 5.43. That is, a BIT film having high ferroelectricity can be formed by matching with the lattice constant of BIT.

Iridium is more easily oxidized than platinum. As shown in the table of FIG. 2, platinum does not easily react with oxygen, whereas iridium oxidizes at high temperatures. When this alloy of platinum and iridium is heat-treated, iridium is slightly oxidized. Since this iridium oxide 20 is formed between the columnar crystals of platinum and blocks the passage through which oxygen in the ferroelectric 8 escapes, oxygen deficiency can be prevented (see FIG. 4).

The ferroelectric capacitor as described above can be used as a nonvolatile memory in combination with a transistor 24, for example, as shown in FIG.

FIG. 6 shows a process of manufacturing a ferroelectric capacitor according to one embodiment of the present invention. The surface of the silicon substrate 2 is thermally oxidized to form a silicon oxide layer 4 (FIG. 6A).
Here, the thickness of the silicon oxide layer 4 was set to 600 nm. Next, using platinum and iridium as targets, an alloy of platinum and iridium is formed on the silicon oxide layer 4 (FIG. 6B). This is the lower electrode 12. Here, it was formed to a thickness of 200 nm.

Next, a PZT film is formed as a ferroelectric layer 8 on the lower electrode 12 by a sol-gel method (FIG. 6C). As starting _{materials, Pb (CH 3 COO) 2} · 3H 2 O, Zr (t chromatography
A mixed solution of OC ₄ H ₉ ) 4 and Ti (i-OC ₃ H ₇ ) ₄ was used. After spin-coating this mixed solution, 150 degrees (Celsius, the same applies hereinafter)
And dry at 400 degrees in a dry air atmosphere.
Preliminary baking for 0 seconds was performed. After repeating this five times, O ₂
A heat treatment of 700 ° C. or more was performed in an atmosphere. Thus, a ferroelectric layer 8 of 250 nm was formed. In addition,
Here, in PbZr _X Ti _{1 -X} O ₃ , x is set to 0.52 (hereinafter referred to as PZT (52 · 48)) to form a PZT film.

Further, an upper electrode 10 is formed on the ferroelectric layer 8 by sputtering using platinum.
D). Thus, a ferroelectric capacitor can be obtained.

In the above embodiment, By the heat treatment for forming the ferroelectric layer 8 (700 degrees or more), the lower electrode 12 is also heat-treated to oxidize iridium. However, this heat treatment may be performed when the lower electrode 12 is formed. It has been found that the improvement of the high-dielectric property, which will be described later, appears significantly when a heat treatment of 400 ° C. or more is performed. Of course, a predetermined effect can be obtained even at a lower temperature. In addition, even without special heat treatment, oxidization of iridium gradually progresses with aging to obtain an effect.

FIG. 7 shows a PZT (52) as the ferroelectric layer 8.
/ 48), using Pt _X Ir _1-X as the lower electrode 12 and changing the composition ratio x of platinum and iridium.
Changes in the remanent polarization Pr and the coercive electric field Ec are shown in a graph. As is clear from this figure, the remanent polarization Pr is higher when the alloy with iridium is used as the lower electrode 12 than when only platinum is used (x = 1.0). It is clear that the value is shown. That is, it can be said that ferroelectricity is improved. A remarkable improvement in characteristics is obtained in the range of 0% to 50% of platinum, and particularly excellent characteristics are obtained at a mixing ratio of 20% to 30% with a peak of about 25% of platinum.

FIG. 8 shows the hysteresis characteristics of the ferroelectric capacitor when only platinum is used as the lower electrode 12. FIG. 8B shows that platinum 25 is used as the lower electrode 12.
2 shows the hysteresis characteristics of a ferroelectric capacitor when an alloy containing 75% iridium and 75% iridium is used. Here, the silicon oxide layer is 600 nm, and the lower electrode 12 is 20 nm.
0 nm and PZT were 250 nm. As is clear from a comparison between the two graphs, the case using the alloy (FIG. 8B) shows more excellent characteristics in remanent polarization Pr.

FIG. 9 shows the hysteresis characteristics of the ferroelectric capacitor when only iridium is used as the lower electrode 12. Thus, even when only iridium is used, the remanent polarization Pr and the coercive electric field Ec are improved. This is presumably because iridium is a columnar crystal like platinum, but its surface or between the crystals is oxidized to change into iridium oxide which is not a columnar crystal.

The use of an alloy of platinum and iridium or iridium for the lower electrode and the upper electrode does not necessarily improve the properties of the dielectric material, but the reasons described above have a complex effect. Seems to be.

FIG. 10 shows a structure of a ferroelectric capacitor according to another embodiment of the present invention. In this embodiment, a titanium layer is provided as a bonding layer 30 between the lower electrode 12 and the silicon oxide layer 4. Adhesion between iridium and silicon oxide layer 4 is not very good. For this reason, the alloy layer may be partially peeled off, and the ferroelectric properties may be degraded.
This is particularly noticeable as the ratio of iridium in the alloy increases. Therefore, in this embodiment, a titanium layer having good adhesion to the silicon oxide layer 4 is provided as the bonding layer 30. Thereby, the ferroelectric characteristics are improved. Note that the titanium layer may be formed by sputtering.

FIG. 11 shows a lower electrode 12 made of iridium.
Below shows the hysteresis characteristics when a titanium layer is provided as the bonding layer 30 below. Here, the silicon oxide layer is 6
000 angstroms, bonding layer 5 nm, lower electrode 1
2 was 200 nm, and PZT was 250 nm. As is clear from the figure, the remanent polarization Pr,
Both the coercive electric field Ec are improved.

In the above embodiment, a titanium layer was used as the bonding layer 30, but any material that can improve the bonding property may be used.
Anything is fine. For example, a platinum layer may be used. FIG. 11B shows hysteresis characteristics when a platinum layer (100 nm) is used as a bonding layer. Again,
As is apparent from comparison with FIG. 9, the remanent polarization Pr and the coercive electric field Ec are improved.

In the above embodiment, matching of lattice constants was achieved by using an alloy of platinum and iridium. However, by using conductors having different lattice constants, the lattice constants can be similarly matched.

In each of the above embodiments, the lower electrode 12 is formed of one layer of alloy or the like, but may be formed of two or more layers. In this case, if an alloy layer of platinum and iridium or an iridium layer is used as a layer in contact with the ferroelectric layer 8, a good ferroelectric layer 8 can be obtained by matching lattice constants. Also, by oxidation of iridium,
The effect of preventing the escape of oxygen from the ferroelectric layer 8 can be obtained if any of the layers is the above alloy layer or iridium layer. However, a higher effect can be obtained by providing an alloy layer or an iridium layer so as to be in contact with the ferroelectric layer 8.

Further, the effect of the escape of oxygen due to the oxidation of iridium can be obtained even when the upper electrode 10 is made of the above-mentioned alloy layer or iridium layer. If both the upper and lower electrodes 10 and 12 are made of an alloy layer or an iridium layer, a greater effect can be obtained.

FIG. 12 shows a capacitor according to another embodiment of the present invention. In this embodiment, a dielectric layer 90 having a high dielectric constant is used instead of the ferroelectric layer 8. On the silicon oxide layer 4, a lower electrode 12 made of an alloy of platinum and iridium (only iridium may be used as described above)
Was formed thereon, and a high dielectric constant thin film having a perovskite structure of SrTiO ₃ and (Sr, Ba) TiO ₃ was formed thereon as the dielectric layer 90. In this case, as in the case of the ferroelectric, the dielectric property was improved. That is, it has been clarified that what has been described about the ferroelectric layer can be applied to a dielectric layer having a high dielectric constant.

[Brief description of the drawings]

FIG. 1 is a diagram showing a composition of a ferroelectric capacitor according to one embodiment of the present invention.

FIG. 2 is a diagram showing physical properties of platinum and iridium.

FIG. 3 is a diagram showing crystal planes of platinum and iridium.

FIG. 4 is a diagram showing a structure in which iridium oxide prevents escape of oxygen in an alloy of platinum and iridium.

FIG. 5 is a diagram showing a nonvolatile memory using a ferroelectric capacitor 22.

FIG. 6 is a diagram showing a manufacturing process of the ferroelectric capacitor.

FIG. 7 is a diagram showing changes in residual polarization Pr and coercive electric field Ec when the mixing ratio of platinum and iridium of the lower electrode 12 is changed.

FIG. 8 is a diagram comparing hysteresis characteristics when using only platinum as the lower electrode and when using an alloy of platinum and iridium as the lower electrode.

FIG. 9 is a diagram showing a hysteresis characteristic when only iridium is used as a lower electrode.

FIG. 10 shows that between a lower electrode 12 and a silicon oxide layer 4
FIG. 4 is a diagram illustrating an example in which a bonding layer 30 is provided.

FIG. 11 is a diagram showing hysteresis characteristics when an iridium layer and a platinum layer are used as the bonding layer 30.

FIG. 12 is a diagram showing an embodiment of a dielectric capacitor having a high dielectric constant.

FIG. 13 is a diagram showing a structure of a conventional ferroelectric capacitor.

FIG. 14 is a diagram showing a state in which oxygen escapes from a lower electrode 6 made of platinum.

[Explanation of symbols]

 2. . . Silicon substrate 4. . . 7. silicon oxide layer . . Ferroelectric layer 10. . . Upper electrode 12. . . Lower electrode 90. . . Dielectric layer having high dielectric constant

Claims (23)

(57) [Claims] 1. A lower electrode having an alloy layer of platinum and iridium having a mixing ratio selected to match a lattice constant of a ferroelectric layer. A ferroelectric capacitor comprising: a ferroelectric layer formed to be in contact with; and an upper electrode formed on the ferroelectric layer. 2. The ferroelectric capacitor according to claim 1, wherein said lower electrode is formed on a silicon oxide layer formed on a substrate, and said lower electrode is in contact with said silicon oxide layer. Having a layer below said alloy or iridium layer. 3. The ferroelectric capacitor according to claim 1, wherein PbZrTiO ₃ is used as said ferroelectric layer, Pt _Y Ir _1-Y is used as a lower electrode layer in contact with said ferroelectric layer, and Y is 0 to 3. 0.5. 4. The ferroelectric capacitor according to claim 3, wherein Y is between 0.2 and 0.3. 5. The ferroelectric capacitor according to claim 1, wherein Bi ₄ Ti ₃ O ₁₂ is used as the ferroelectric layer, and Pt _Y Ir _1-Y is used as a lower electrode layer in contact with the ferroelectric layer. Y those characterized by being 0.8. 6. A lower electrode having an alloy layer of two or more conductors having different lattice constants and having a mixing ratio selected to match the lattice constant of a ferroelectric layer. A ferroelectric capacitor, comprising: a ferroelectric layer formed so as to be in contact with an alloy layer of: and an upper electrode formed on the ferroelectric layer. 7. The ferroelectric capacitor according to claim 6, wherein said alloy layer is an alloy layer containing at least iridium. 8. A lower electrode, a ferroelectric layer formed on the lower electrode, and a mixing ratio formed on the ferroelectric layer and selected to match a lattice constant of the ferroelectric layer. And a top electrode having an alloy layer of platinum and iridium. 9. A lower electrode having an alloy layer of platinum and iridium having a mixing ratio selected so as to match a lattice constant of a dielectric layer having a high dielectric constant. A dielectric capacitor having a high dielectric constant, comprising: a dielectric layer having a high dielectric constant formed in contact with the alloy layer; and an upper electrode formed on the dielectric layer having a high dielectric constant. 10. A dielectric capacitor having a high dielectric constant according to claim 9 or 10, wherein said lower electrode is formed on a silicon oxide layer formed on a substrate. A bonding layer in contact with the silicon oxide layer is provided below the alloy layer or the iridium layer. 11. A lower electrode having an alloy layer of two or more conductors having different lattice constants, formed so as to have a mixture ratio selected to match the lattice constant of a dielectric layer having a high dielectric constant. A dielectric layer having a high dielectric constant formed on the lower electrode so as to be in contact with an alloy layer of the lower electrode; and an upper electrode formed on the dielectric layer having a high dielectric constant. A dielectric capacitor having a ratio. 12. A dielectric capacitor having a high dielectric constant according to claim 11, wherein said alloy layer is an alloy layer containing at least iridium. 13. A lower electrode, a dielectric layer having a high dielectric constant formed on the lower electrode, and a dielectric layer formed on the dielectric layer having a high dielectric constant.
A dielectric capacitor having a high dielectric constant, comprising: an upper electrode having an alloy layer of platinum and iridium, the upper electrode having a mixing ratio selected to match the lattice constant of the dielectric layer . 14. forming, as a lower electrode, an alloy layer of platinum and iridium on a substrate by sputtering, the alloy layer having a mixing ratio selected to match the lattice constant of the ferroelectric layer; Forming a ferroelectric layer so as to be in contact with the ferroelectric layer; and forming an upper electrode on the ferroelectric layer. 15. A step of forming a silicon oxide layer on a substrate, forming a bonding layer on the silicon oxide layer, and matching a lattice constant of a ferroelectric layer on the bonding layer. Forming an alloy layer of platinum and iridium or an iridium layer having a mixing ratio selected to form a lower electrode, forming a ferroelectric layer on the lower electrode, Forming an upper electrode on the ferroelectric capacitor. 16. The method for manufacturing a ferroelectric capacitor according to claim 14, further comprising a step of heat-treating the lower electrode at 400 ° C. or more. 17. The method for manufacturing a ferroelectric capacitor according to claim 16, wherein the heat treatment step also serves as a heat treatment for forming a ferroelectric layer. 18. A method of manufacturing a ferroelectric capacitor having a lower electrode and an upper electrode at both ends of a ferroelectric layer, wherein the lower electrode is an alloy of two or more types of metals having different lattice constants, and the composition ratio of the alloy Wherein the lattice constant of the alloy is changed to match the lattice constant of the ferroelectric layer. 19. forming, as a lower electrode, an alloy layer of platinum and iridium on a substrate by sputtering, the alloy layer having a mixing ratio selected to match the lattice constant of the ferroelectric layer; Forming a dielectric layer having a high dielectric constant so as to be in contact with the upper layer, forming an upper electrode on the dielectric layer having a high dielectric constant, and manufacturing a dielectric capacitor having a high dielectric constant. Method. 20. A step of forming a silicon oxide layer on a substrate, a step of forming a bonding layer on the silicon oxide layer, and a lattice constant of a dielectric layer having a high dielectric constant on the bonding layer. Forming an alloy layer (or iridium layer) of platinum and iridium so as to have a mixing ratio selected to match with, and forming a lower electrode; a dielectric having a high dielectric constant on the lower electrode; Forming a body layer; and forming an upper electrode on the dielectric layer having a high dielectric constant. A method for manufacturing a dielectric capacitor having a high dielectric constant, comprising: 21. The method for manufacturing a dielectric capacitor having a high dielectric constant according to claim 19 or 20, further comprising a step of heat-treating the lower electrode at a temperature of 400 degrees Celsius or more. 22. A method of manufacturing a dielectric capacitor having a high dielectric constant, wherein the heat treatment step also serves as a heat treatment for forming a dielectric layer having a high dielectric constant. 23. A method of manufacturing a dielectric capacitor having a high dielectric constant having a lower electrode and an upper electrode at both ends of a dielectric layer having a high dielectric constant, wherein the lower electrode is formed of two or more kinds of metals having different lattice constants A high dielectric constant dielectric material characterized by changing the composition ratio of the alloy to change the lattice constant of the alloy to match the lattice constant of the dielectric layer having the high dielectric constant. Method for manufacturing a body capacitor.