JPH0964300A - Ferroelectric memory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of crystallinity of a ferroelectric film caused by a lower electrode in a ferroelectric memory. SOLUTION: A silicon oxide film 12 is formed on a silicon substrate 10, a lower electrode 18 made up of a platinum film 14 and an electrically- conductive oxide film 16 is formed on the film 12, and a ferroelectric film 20 and an upper electrode 22 are formed on the conductive oxide film 16 in this order.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferroelectric memory, and more particularly to an electrode provided in contact with a ferroelectric film forming the ferroelectric memory.

[0002]

2. Description of the Related Art A ferroelectric memory is usually formed as a structure in which an upper electrode and a lower electrode sandwich a ferroelectric film above and below. The upper electrode and the lower electrode apply a voltage to the ferroelectric film to control the polarization (spontaneous polarization) formed in the ferroelectric film. As the ferroelectric film, PLZ is generally used.
T, PZT, PTO or the like is used. As the lower electrode or the upper electrode, platinum (Pt) is used, for example.

For details of the ferroelectric film and the ferroelectric memory, see, for example, the document “Ceramics, Vol. 30, N.
o. 6, pp. 499-507 (1995) ".

[0004]

However, in the conventional ferroelectric memory, the following problems occur when platinum is used as the lower electrode and the upper electrode.

First, there are problems in that it is not preferable in terms of cost and workability is poor. Furthermore, since a ferroelectric film, which is an oxide, is formed on platinum, which is a metal, the interface is heterogeneous and not stable. As a result, a layer having poor crystallinity is formed near the interface between the ferroelectric layer and the platinum electrode, and the performance of the ferroelectric memory is deteriorated.

Therefore, conventionally, there has been a demand for an electrode which does not cause deterioration of the performance of the ferroelectric memory.

[0007]

According to the ferroelectric memory of the present invention, in a ferroelectric memory having an upper electrode, a lower electrode, and a ferroelectric film sandwiched between the upper electrode and the lower electrode, The lower electrode is characterized by including at least a conductive oxide film having a perovskite structure in the surface region on the ferroelectric film side.

As described above, since the ferroelectric film is grown on the conductive oxide film having the perovskite structure, it is possible to prevent the growth of the initial layer having poor crystallinity.

Further, according to the ferroelectric memory of the present invention, in the above-described ferroelectric memory, the lower electrode is in contact with the conductive oxide film, and the conductive oxide film is in contact with the conductive oxide film on the side opposite to the ferroelectric film. And a platinum film that is formed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that FIGS. 1 and 2 merely schematically show the shapes, sizes, and positional relationships of constituent elements (components) to the extent that the present invention can be understood, and the numerical values and other conditions described below. It is to be understood that is only a preferred example, and the present invention is not limited to the embodiments of the present invention.

FIG. 1 is a sectional view of the structure of a ferroelectric memory for explaining the structure of the embodiment of the present invention.

As shown in FIG. 1, the ferroelectric memory of the present invention has an upper electrode 22, a lower electrode 18, and a ferroelectric film 20 sandwiched between the upper electrode 22 and the lower electrode 18. It is a dielectric memory and has a structure in which the lower electrode 18 includes at least the conductive oxide film 16 having a perovskite structure in the surface region on the ferroelectric film 20 side. Further, in this ferroelectric memory, the lower electrode 18
Are formed of the conductive oxide film 16 and the platinum film 14 which is in contact with the conductive oxide film 16 on the side opposite to the ferroelectric film 20.

In the embodiment of the present invention, a base on which a ferroelectric memory is formed is composed of a substrate and an oxide film covering the surface thereof, and a silicon (Si) wafer, that is, a silicon substrate 10 is used as the substrate. Therefore, a silicon oxide (SiO ₂ ) film 12 is used as an oxide film covering the silicon substrate 10. In addition, the lower electrode 18
Is composed of a platinum (Pt) film 14 and a conductive oxide film 16, and the conductive oxide film 16 is Sr _0.3 as an example.
La _0.7 CoO ₃ is used. The ferroelectric film 20 is formed of, for example, PLZT (Pb _1.1 La _0.03 Zr _0.5 Ti _0.5 O
₃ ), the upper electrode 22 is formed by using platinum. It has been confirmed by X-ray diffraction that the conductive oxide film 16 and the ferroelectric film 20 have a perovskite structure.

FIG. 2 is a view for explaining the manufacturing process of the embodiment of the present invention, and each drawing is a cross section of the structure obtained at each process step.

In the embodiment of the present invention, a silicon substrate 10 is used as a substrate, and this is subjected to, for example, thermal oxidation treatment to form a silicon oxide film 12 as an insulating film on the surface of the substrate ((A) of FIG. 2). . The thickness of the silicon oxide film 12 may be such that the silicon substrate 10 and the ferroelectric memory formed on the silicon substrate 10 can be sufficiently electrically insulated.

Next, a platinum film is formed on the silicon oxide film 12 by, for example, a sputtering method to form a platinum film 14 (FIG. 2B).

Then, a conductive oxide film 16 is formed on the upper surface of the platinum film 14 ((C) of FIG. 2). Lower electrode 18
Is composed of the platinum film 14 and the conductive oxide film 16. The formation of the conductive oxide film 16 will be described below.

[Formation of Conductive Oxide Film] (1) A Sr _0.3 La _0.7 CoO ₃ film forming solution is spin-coated on a platinum film to form a coating film. (2) The coating film is dried at 150 ° C. for 30 minutes. (3) The dried coating film is pre-baked at 460 ° C. for 30 minutes. (4) The pre-baked coating film is baked at 650 ° C. for 60 minutes.

Here, in the spin coating in the step (1), Sr _0.3 L is applied to the platinum film 14 formed on the upper side of the substrate 10.
The a _0.7 CoO ₃ film forming liquid is dropped, and immediately the substrate is rotated on an axis perpendicular to the surface and blown off by the centrifugal acceleration.

Sr _0.3 L as a coating film used here
a _0.7 CoO ₃ film forming liquid is Sr (OC ₂ H ₄ OC ₂ H
₅ ) ₂ , La (OC ₂ H ₄ OC ₂ H ₅ ) ₃ , and Co
0.2 mol using (OC ₂ H ₄ OC ₂ H ₅ ) ₃ as a solvent
/ L alcohol solution (ethanol, ethoxypropanol).

In the embodiment of the present invention, the rotation speed of the substrate is 500 rotations / minute for 5 seconds and 2000 rotations / minute for 30 seconds. As described above, first, the Sr _0.3 La _0.7 CoO ₃ forming liquid is made to spread on the wafer by low-speed rotation, and then the excess forming liquid is blown off by high-speed rotation to form a coating film.

Next, by the process of (2), Sr _0.3 La
The solvent in the _0.7 CoO ₃ coating film is evaporated and the organic functional groups are burned. Then, by the process of (3), dried S
The organic functional groups remaining in the r _0.3 La _0.7 CoO ₃ film are burned and calcination is performed. After that, main baking is performed to crystallize the film.

After forming the conductive oxide film 16, a ferroelectric film 20 is formed on the conductive oxide film 16 (FIG. 2).
(D)).

The ferroelectric film 20 is formed by the same method as the conductive oxide film 16. That is, in the aforementioned [Formation of the conductive oxide film, instead of Sr _0.3 La _0.7 CoO _{3-forming liquid, PLZT (Pb 1.1 La 0.03 Zr} 0.5 T
This may be performed using a i _0.5 O ₃ ) forming liquid (trade name “metal polymer solution” manufactured by Epoxy Technology Co., Ltd.).

Finally, a platinum film is formed as the upper electrode 22 by, for example, the sputtering method ((E) in FIG. 2).

Although each heat treatment in the above-described embodiment of the invention is performed in the air, it may be performed in an oxygen atmosphere.

In the embodiment of the present invention, the film thickness of each layer is as shown below. Silicon oxide film 12: 0.3 μm Platinum film 14: 0.06 μm Conductive oxide film 16: 0.08 μm Ferroelectric film 20: 0.38 μm Upper electrode 22: 0.3 μm Further, the upper electrode 22 has a cylindrical shape. , Its diameter is 0.2m
m.

Next, the characteristics of the prepared ferroelectric memory will be described. FIG. 3 is a diagram schematically showing the relationship between the applied voltage V and the polarization amount P formed in the ferroelectric film.
The voltage value V of the upper electrode 22 with the lower electrode 18 as a reference is plotted on the horizontal axis, and the polarization amount P for each voltage value V is plotted on the vertical axis. Coordinates of point F from point A in the figure, respectively _{A (V max, P max)} B (0, P r) C (-V c, 0) D (-V max, -P max) E (0, −P _r ) F (V _c , 0). The arrow in the figure indicates that the polarization state of the ferroelectric film changes in the direction of the arrow. For example, starting from point A, A → B → C → D → E → F → A. It shows that it is a changing PV hysteresis curve. In the figure,
The maximum value of the applied voltage in the positive direction is V _max, and the polarization amount corresponding to V _max is the maximum polarization amount P _max . The maximum value of the applied voltage in the negative direction is −V _max, and the polarization amount corresponding to −V _max is −P _max . Further, the values of the polarization amount when the applied voltage is zero are the residual polarization amounts P _r and −P _r . Further, the polarization amount is coercive electric field V _c the value of the applied voltage when the zero and -V _c. When the value of the maximum applied voltage V _max is different when measuring the hysteresis curve, the size and shape of the hysteresis curve, that is, the maximum polarization amount P depending on the value of the V _max.
The values of _max , the residual polarization amount P _r , and the coercive electric field V _c change. In the data of the following figures, hysteresis curves are measured by changing the value of the maximum applied voltage value V _max , and the physical quantities such as the residual polarization amount and the coercive electric field are measured from the respective hysteresis curves, and these are plotted vertically. the axis, in which took V _max on the horizontal axis.

FIG. 4 shows the polarization amount P _max (unit: μC / cm ² ) formed in the ferroelectric film with respect to the maximum voltage value V _max (unit: volt (V)) applied to the ferroelectric film. It is a figure which shows a relationship. As described in FIG. 3, the polarization amount P _max is read from each PV hysteresis curve measured by changing the value of the maximum applied voltage V _max , and the horizontal axis represents V _max and the vertical axis represents P _max. Is.

In the figure, the data points represented by ◯ indicate the case where the lower electrode 18 is composed of only the platinum film 14, and the data points represented by ⋄ indicate that the lower electrode 18 and the platinum film 14 are conductive. This is the case where the oxide film 16 is formed (this symbol is used in FIGS. 4 to 8). As shown in the figure, in both curves, the value of P _max increases with the increase of V _max , but the case where the conductive oxide film is used (curve indicated by ⋄) is not used ( Curve)
The rate of increase is large. Therefore, the maximum polarization amount increases by using the conductive oxide film as the electrode.

FIG. 5 is a diagram showing the relationship between the maximum applied voltage V _max (unit: volt (V)) and the residual polarization amount P _r (unit: μC / cm ² ).

In FIG. 5A, the value of the amount of polarization when the applied voltage is gradually reduced from the maximum voltage value V _max to zero is defined as P _r . That is, in FIG. 3, the state of the point A is changed to the state of the point B, and the value of the polarization amount at the point B is set to P _r . On the other hand, FIG. 5B shows -V _max.
The value of the polarization amount when the voltage is changed from (state at point D in FIG. 3) toward zero and the applied voltage becomes zero (state at point E in FIG. 3) is −P _r . Similar to FIG. 4, the residual polarization amount is read from the PV hysteresis curve measured by changing the value of the maximum applied voltage V _max , V _max is plotted on the horizontal axis, and P _r corresponding to each is plotted on the vertical axis. I took it.

In both (A) and (B) of FIG. 5, the case where the conductive oxide film is used (curve indicated by ⋄) is larger than the case where it is not used (curve indicated by ∘). It can be seen that the amount of polarization is large. Further, comparing (A) and (B) of FIG. 5, the difference in the value when the oxide electrode is used is smaller than that when the oxide electrode is not used.

FIG. 6 shows the coercive electric field V _c (unit: volt (V)) with respect to the maximum applied voltage V _max (unit: volt (V)).
It is a figure which shows the relationship of.

FIG. 6A shows -V _max (point D in FIG. 3).
Was changed toward zero from 0 to 0, and the value of the applied voltage when the polarization amount became zero (point F in FIG. 3) was defined as V _c .
On the other hand, in FIG. 6B, the applied voltage is lowered from the state of V _max (point A in FIG. 3) and the polarization amount is zero (C in FIG. 3).
The value of the applied voltage when it is the point) was -V _c. V
By changing the value of _max and measuring the hysteresis curve, V _max
Are plotted on the horizontal axis and V _c for each is plotted on the vertical axis.

From both FIGS. 6A and 6B, it can be seen that the continuity (linearity) is better when the conductive oxide film is used than when it is not used. . That is,
When the conductive oxide electrode is not used (curve shown by a circle), there is a large jump in the data, and the variation in the data extends over a wide range. On the other hand, when the conductive oxide film is used (curve indicated by ⋄), variation in data is smaller. Also, comparing (A) and (B) of FIG. 6,
It can be seen that the difference in the magnitude of the applied voltage for canceling the polarization having the same magnitude but different direction is smaller in the case of using the conductive oxide film than in the case of not using the conductive oxide film.

FIG. 7A shows the electric capacitance C of the ferroelectric film with respect to the maximum applied voltage V _max (unit: volt (V)).
It is a figure which shows the relationship of (unit is nF), (B) of FIG.
FIG. 4 is a diagram showing a relationship of a relative dielectric constant K _ef of a ferroelectric film with respect to a maximum applied voltage V _max (unit is Volt (V)).

According to each drawing of FIG. 7, the case where the conductive oxide film is used (curve indicated by ⋄) is not used (circle).
It can be seen that the values of the electric capacity and the relative dielectric constant are larger than those of the curve indicated by the mark). This is because the conductive oxide film is used as an electrode and the ferroelectric film is formed thereon, so that a layer having poor crystallinity is not formed.

When a ferroelectric film, which is an oxide, is grown on a platinum film, the crystalline state at the initial stage of growth is not a good state, and a film in a good crystalline state, that is, a perovskite structure is formed on this layer. A film having is formed. Therefore, the ferroelectric film has a two-layer structure including an initial layer and an upper layer having a perovskite structure. The electric capacity of the initial layer is smaller than that of the upper layer, and the electric resistance of the initial layer is larger than that of the upper layer. Therefore, the electric capacity of the entire ferroelectric film becomes smaller than that of the case where the entire ferroelectric film is a perovskite layer, and conversely the electric resistance becomes large.

On the other hand, when a conductive oxide film is formed on a platinum film and then a ferroelectric film is formed on the oxide film, a perovskite structure is formed on the surface layer of the conductive oxide film. Are generated, the ferroelectric film formed thereon has a perovskite structure, and thus no initial layer is formed.

FIG. 8A shows the relationship between the maximum applied voltage V _max (unit: volt (V)) and the leak current I of the ferroelectric film (unit: ampere (A)). In the figure, each curve represented by ◯ and Δ is the case where the conductive oxide film is not used as an electrode, and the curve represented by ◯ is the case where the applied voltage V _max is positive. , The curve indicated by Δ marks is the case where the applied voltage V _max is negative. Also,
The curves indicated by ⋄ and □ are when the conductive oxide film is used as an electrode, and the curves indicated by ⋄ are when the applied voltage V _max is positive, and are indicated by □. The curve shown is for a negative applied voltage V _max .

Further, FIG. 8B shows the maximum applied voltage V
The relationship is the thin-film resistance value R (unit: ohm (Ω)) of the ferroelectric film with respect to _max (unit: volt (V)). The meanings of the marks ◯, Δ, ◇, and □ in the figure are the same as those in FIG.

As shown in FIG. 8, when the conductive oxide film is used as the electrode, the leak current is increased and the thin film resistance value is decreased as compared with the case where the conductive oxide film is not used. It can be seen that the initial layer is not formed.

Numerical values of the data shown in FIGS. 4 to 8 are shown in Tables 1 to 11. Table 1 (a) shows the data when the oxide film electrode of FIG. 4 is not used (indicated by a circle).
It is a table showing the numerical value of. Table 1 (b) is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 4 is used.

Table 2 (a) is a table showing numerical values of data (indicated by ◯) when the oxide film electrode of FIG. 5 (A) is not used. Table 2 (b) is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 5 (A) is used.

Table 3 (a) is a table showing numerical values of data (indicated by ◯) when the oxide film electrode of FIG. 5 (B) is not used. Table 3 (b) is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 5B is used.

Table 4 (a) is a table showing numerical values of data (indicated by a circle) when the oxide film electrode of FIG. 6 (A) is not used. Table 4 (b) is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 6 (A) is used.

Table (A) is a table showing numerical values of data (indicated by ◯) when the oxide film electrode of FIG. 6B is not used. (B) of Table 5 is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of (B) of FIG. 6 is used.

Table 6 (a) is a table showing numerical values of data (indicated by a circle) when the oxide film electrode of FIG. 7 (A) is not used. (B) of Table 6 is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of (A) of FIG. 7 is used.

Table 7 (a) is a table showing numerical values of data (indicated by a circle) when the oxide film electrode of FIG. 7 (B) is not used. Table 7 (b) is a table showing numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 7 (B) is used.

Table (a) shows the numerical value of data (indicated by a circle) when the oxide film electrode of FIG. 8 (A) is not used and a voltage is applied in the positive direction. It is a table.
8B is a table showing numerical values of data (indicated by Δ) when the oxide film electrode of FIG. 8A is not used and a voltage is applied in the negative direction. .

Table 9A shows the numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 8A is used and a voltage is applied in the positive direction. It is a table. (B) of Table 9 is a case where the oxide film electrode of (A) of FIG. 8 is used, and is a table showing numerical values of data (indicated by □) when a voltage is applied in the negative direction. .

Table 10A shows the numerical values of data (indicated by a circle) when the oxide film electrode of FIG. 8B is not used and a voltage is applied in the positive direction. It is a table. 8B is a table showing the numerical values of data (indicated by Δ) when the oxide film electrode of FIG. 8B is not used and a voltage is applied in the negative direction. .

Table 11 (a) shows the numerical values of data (indicated by ⋄) when the oxide film electrode of FIG. 8 (B) is used and a voltage is applied in the positive direction. It is a table.
(B) of Table 11 is a case where the oxide film electrode of (B) of FIG. 8 is used, and is a table showing numerical values of data (indicated by □) when a voltage is applied in the negative direction. .

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

[Table 5]

[0060]

[Table 6]

[0061]

[Table 7]

[0062]

[Table 8]

[0063]

[Table 9]

[0064]

[Table 10]

[0065]

[Table 11]

From the above description, the lower electrode 18 of the ferroelectric memory includes the conductive oxide film 16 having at least the perovskite structure in the surface region on the ferroelectric film 20 side,
The lower electrode 18 is in contact with the conductive oxide film 16 and the platinum film 1 in contact with the conductive oxide film 16 on the side opposite to the ferroelectric film 20.
It is understood that the performance of the ferroelectric memory is improved as a result of the structure formed by 4 and 4. This is because an initial layer having poor crystallinity, which is generated when the ferroelectric film is directly grown on the upper surface of the platinum film, is not formed.

Further, the origin of the ferroelectric characteristics of the ferroelectric substance is that it has a perovskite structure. According to the measurement results of FIG. 4 to FIG. 8, each characteristic is improved as a result of using the conductive oxide film 16 having the perovskite structure as the lower electrode and growing the ferroelectric film 20 thereon. I understand. It is judged that this is because the initial layer is not formed as described above.
Furthermore, as described above, it has been confirmed by X-ray diffraction that the ferroelectric film and the oxide electrode of the ferroelectric memory produced have a perovskite structure.

Next, as the conductive oxide film 16, Sr
_A case where a conductive oxide other than _0.3 La _0.7 CoO ₃ is used will be described.

As the conductive oxide film 16 having the perovskite structure, ABO ₃ (A: alkaline earth metal, B:
Transition metal, oxide of O: oxygen), specifically, Sr _x La _1-x CoO ₃ Ca _x La _1-x CoO ₃ LaCrO ₃ Ca _x La _1-x CrO ₃ Sr _x La _1-x CrO ₃ Etc. are used. Here, the value of the composition ratio x is 0 <x <1, but its preferable value differs depending on each substance. For example, in Ca _x La _1-x CrO ₃ , x is preferably 0.1, and in Sr _x La _1-x CoO ₃ , x is preferably 0.3.

The embodiments of the present invention have been described above. According to the embodiment of the present invention, conductive oxide film 16 is formed on platinum film 14 of lower electrode 18, and ferroelectric film 20 is formed on the upper surface of conductive oxide film 16. Since a perovskite layer is formed on the surface region of the conductive oxide film 16 on the side opposite to the platinum film 14, the ferroelectric film 20 formed on this layer also has a perovskite structure.

As described above, the entire ferroelectric film can be made into a good crystal state, a large-capacity ferroelectric film that is uniform in the depth direction can be obtained, and each characteristic of the ferroelectric film ( The maximum polarization amount, the residual polarization amount, the coercive electric field, the dielectric constant, etc.) are improved, and the performance of the ferroelectric memory is improved, which is a remarkable effect.

[0072]

As is apparent from the above description, according to the ferroelectric memory of the present invention, the ferroelectric memory having the upper electrode and the lower electrode and the ferroelectric film sandwiched between the upper electrode and the lower electrode is provided. In the dielectric memory, the lower electrode includes a conductive oxide film having at least a perovskite structure in the surface region on the ferroelectric film side, or the lower electrode has a conductive oxide film and a conductive oxide film. A ferroelectric memory characterized in that it is formed by a platinum film that is in contact with the ferroelectric film on the opposite side to the ferroelectric film, and as a result, the ferroelectric memory formed on the conductive oxide film. Since the body film has a uniform perovskite structure, the characteristics of the ferroelectric film are improved, and the performance of the ferroelectric memory is improved, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining a configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view for explaining the manufacturing process according to the embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between an applied voltage and a polarization amount.

FIG. 4 is a diagram showing a relationship between a maximum applied voltage and a maximum polarization amount.

5A is a maximum applied voltage and a residual polarization amount (B in FIG. 3).
Is a diagram showing the relationship with the residual polarization amount at the point),
FIG. 4B is a diagram showing the relationship between the maximum applied voltage and the residual polarization amount (the residual polarization amount at point E in FIG. 3).

6A is a diagram showing the relationship between the coercive electric field (coercive electric field at point F in FIG. 3) with respect to the maximum applied voltage, and FIG. 6B is the coercive electric field with respect to the maximum applied voltage (resistive field at point C in FIG. 3). It is a figure which shows the relationship of (electric field).

FIG. 7A is a diagram showing the relationship of the electric capacity with respect to the maximum applied voltage, and FIG. 7B is a diagram showing the relationship of the relative dielectric constant with respect to the maximum applied voltage.

FIG. 8A is a diagram showing the relationship between the maximum applied voltage and the magnitude of the leakage current, and FIG. 8B is a view showing the relationship between the maximum applied voltage and the thin film resistance.

[Explanation of symbols]

 10: Silicon substrate 12: Silicon oxide film 14: Platinum film 16: Conductive oxide film 18: Lower electrode 20: Ferroelectric film 22: Upper electrode

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 29/788 29/792

Claims (2)

[Claims] 1. A ferroelectric memory having an upper electrode, a lower electrode, and a ferroelectric film sandwiched between the upper electrode and the lower electrode, wherein the lower electrode has a surface on the ferroelectric film side. A ferroelectric memory comprising a conductive oxide film having at least a perovskite structure in a region. 2. The ferroelectric memory according to claim 1, wherein the lower electrode is in contact with the conductive oxide film, and platinum that is in contact with the conductive oxide film on the side opposite to the ferroelectric film. A ferroelectric memory comprising a film and a film.